Name: size matters: measurement of capsule diameter in cryptococcus neoformans
Uploaded: 2018-02-27T15:00:00
Description: Watch this Scientific Journal Video about Size Matters: Measurement of Capsule Diameter in Cryptococcus neoformans at JoVE.com

Wij danken de moleculaire Biosciences (MOBI) doctorale programma en de biologie-afdeling op Middle Tennessee State University (MTSU) voor het verstrekken van de financiering voor deze studie. Het project werd ook gedeeltelijk gefinancierd door een speciale projecten subsidie toegekend aan D.E.N. door de MTSU Foundation.

Opmerking: C. neoformans is een ziekteverwekker Biosafety Level 2 (BSL-2) en onderzoekers die werken met het juiste voorzorgsmaatregelen moeten nemen. Gedetailleerde procedures over hoe te veilig werken met BSL-2 ziekteverwekkers kan worden gevonden op het Center for Disease Control (CDC) website, maar het is belangrijk op te merken dat alle personen die in contact C. neoformans komen goed moeten worden opgeleid in behandeling ziekteverwekkers en altijd passende persoonlijke beschermingsmiddelen (PBM), ...

<ol>
	<li>Park, B. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimation+of+the+current+global+burden+of+cryptococcal+meningitis+among+persons+living+with+HIV/AIDS.">Estimation of the current global burden of cryptococcal meningitis among persons living with HIV/AIDS.</a> AIDS. 23 (4), 525-530 (2009).</li><li>Coelho, C., Bocca, A. L., Casadevall, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+intracellular+life+of+Cryptococcus+neoformans.">The intracellular life of Cryptococcus neoformans.</a> Annu Rev Pathol. 9, 219-238 (2014).</li><li>Rajasingham, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Global+burden+of+disease+of+HIV-associated+cryptococcal+meningitis:+an+updated+analysis.">Global burden of disease of HIV-associated cryptococcal meningitis: an updated analysis.</a> Lancet Infect Dis. 17 (8), 873-881 (2017).</li><li>Limper, A. H., Adenis, A., Le, T., Harrison, T. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fungal+infections+in+HIV/AIDS.">Fungal infections in HIV/AIDS.</a> Lancet Infect Dis. 17 (11), e334-e343 (2017).</li><li>Casadevall, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Crisis+in+Infectious+Diseases:+2+Decades+Later.">Crisis in Infectious Diseases: 2 Decades Later.</a> Clin Infect Dis. 64 (7), 823-828 (2017).</li><li>McClelland, E. E. C., Eisenmann, A., H, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ch+6.">Ch 6.</a> New Insights in Medical Mycology. , 131-157 (2007).</li><li>Leopold Wager, C. M., Wormley, F. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Classical+versus+alternative+macrophage+activation:+the+Ying+and+the+Yang+in+host+defense+against+pulmonary+fungal+infections.">Classical versus alternative macrophage activation: the Ying and the Yang in host defense against pulmonary fungal infections.</a> Mucosal Immunol. 7 (5), 1023-1035 (2014).</li><li>Kwon-Chung, K. J., Rhodes, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Encapsulation+and+melanin+formation+as+indicators+of+virulence+in+Cryptococcus+neoformans.">Encapsulation and melanin formation as indicators of virulence in Cryptococcus neoformans.</a> Infect Immun. 51 (1), 218-223 (1986).</li><li>Vecchiarelli, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Elucidating+the+immunological+function+of+the+Cryptococcus+neoformans+capsule.">Elucidating the immunological function of the Cryptococcus neoformans capsule.</a> Future Microbiol. 8 (9), 1107-1116 (2013).</li><li>Murphy, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+cryptococcal+antigens+on+cell-mediated+immunity.">Influence of cryptococcal antigens on cell-mediated immunity.</a> Rev Infect Dis. 10 Suppl 2, S432-S435 (1988).</li><li>Cherniak, R., Morris, L. C., Belay, T., Spitzer, E. D., Casadevall, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Variation+in+the+structure+of+glucuronoxylomannan+in+isolates+from+patients+with+recurrent+cryptococcal+meningitis.">Variation in the structure of glucuronoxylomannan in isolates from patients with recurrent cryptococcal meningitis.</a> Infect Immun. 63 (5), 1899-1905 (1995).</li><li>Collins, H. L., Bancroft, G. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Encapsulation+of+Cryptococcus+neoformans+impairs+antigen-specific+T-cell+responses.">Encapsulation of Cryptococcus neoformans impairs antigen-specific T-cell responses.</a> Infect Immun. 59 (11), 3883-3888 (1991).</li><li>Yasuoka, A., Kohno, S., Yamada, H., Kaku, M., Koga, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+molecular+sizes+of+Cryptococcus+neoformans+capsular+polysaccharide+on+phagocytosis.">Influence of molecular sizes of Cryptococcus neoformans capsular polysaccharide on phagocytosis.</a> Microbiol Immunol. 38 (11), 851-856 (1994).</li><li>Robertson, E. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cryptococcus+neoformans+ex+vivo+capsule+size+is+associated+with+intracranial+pressure+and+host+immune+response+in+HIV-associated+cryptococcal+meningitis.">Cryptococcus neoformans ex vivo capsule size is associated with intracranial pressure and host immune response in HIV-associated cryptococcal meningitis.</a> J Infect Dis. 209 (1), 74-82 (2014).</li><li>Cordero, R. J., Bergman, A., Casadevall, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temporal+behavior+of+capsule+enlargement+by+Cryptococcus+neoformans.">Temporal behavior of capsule enlargement by Cryptococcus neoformans.</a> Eukaryot Cell. 12 (10), 1383-1388 (2013).</li><li>O'Meara, T. R., Alspaugh, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Cryptococcus+neoformans+capsule:+a+sword+and+a+shield.">The Cryptococcus neoformans capsule: a sword and a shield.</a> Clin Microbiol Rev. 25 (3), 387-408 (2012).</li><li>McClelland, E. E., Smith, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gender+specific+differences+in+the+immune+response+to+infection.">Gender specific differences in the immune response to infection.</a> Archivum Immunologiae et Therapiae Experimentalis. 59 (3), (2011).</li><li>McClelland, E. E., Perrine, W. T., Potts, W. K., Casadevall, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Relationship+of+virulence+factor+expression+to+evolved+virulence+in+mouse-passaged+Cryptococcus+neoformans+lines.">Relationship of virulence factor expression to evolved virulence in mouse-passaged Cryptococcus neoformans lines.</a> Infect Immun. 73 (10), 7047-7050 (2005).</li><li>Zaragoza, O., Fries, B. C., Casadevall, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induction+of+capsule+growth+in+Cryptococcus+neoformans+by+mammalian+serum+and+CO(2).">Induction of capsule growth in Cryptococcus neoformans by mammalian serum and CO(2).</a> Infect Immun. 71 (1), 6155-6164 (2003).</li><li>Vartivarian, S. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+cryptococcal+capsular+polysaccharide+by+iron.">Regulation of cryptococcal capsular polysaccharide by iron.</a> J Infect Dis. 167 (1), 186-190 (1993).</li><li>McFadden, D. C., Fries, B. C., Wang, F., Casadevall, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Capsule+structural+heterogeneity+and+antigenic+variation+in+Cryptococcus+neoformans.">Capsule structural heterogeneity and antigenic variation in Cryptococcus neoformans.</a> Eukaryot Cell. 6 (8), 1464-1473 (2007).</li><li>Garcia-Hermoso, D., Dromer, F., Janbon, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cryptococcus+neoformans+capsule+structure+evolution+in+vitro+and+during+murine+infection.">Cryptococcus neoformans capsule structure evolution in vitro and during murine infection.</a> Infect Immun. 72 (6), 3359-3365 (2004).</li><li>Gates, M. A., Thorkildson, P., Kozel, T. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+architecture+of+the+Cryptococcus+neoformans+capsule.">Molecular architecture of the Cryptococcus neoformans capsule.</a> Mol Microbiol. 52 (1), 13-24 (2004).</li><li>Pontes, B., Frases, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Cryptococcus+neoformans+capsule:+lessons+from+the+use+of+optical+tweezers+and+other+biophysical+tools.">The Cryptococcus neoformans capsule: lessons from the use of optical tweezers and other biophysical tools.</a> Front Microbiol. 6, 640 (2015).</li><li>Shen, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automated+tracking+of+gene+expression+in+individual+cells+and+cell+compartments.">Automated tracking of gene expression in individual cells and cell compartments.</a> J R Soc Interface. 3 (11), 787-794 (2006).</li><li>Dorn, J. F., Danuser, G., Yang, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Computational+processing+and+analysis+of+dynamic+fluorescence+image+data.">Computational processing and analysis of dynamic fluorescence image data.</a> Methods Cell Biol. 85, 497-538 (2008).</li><li>Nketia, T. A., Sailem, H., Rohde, G., Machiraju, R., Rittscher, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+live+cell+images:+Methods,+tools+and+opportunities.">Analysis of live cell images: Methods, tools and opportunities.</a> Methods. , 65-79 (2017).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Biosafety in Microbiological and Biomedical Laboratories. , 33-38 (2015).</li><li>Kwon, O., Kang, S. T., Kim, S. H., Kim, Y. H., Shin, Y. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Maximum+intensity+projection+using+bidirectional+compositing+with+block+skipping.">Maximum intensity projection using bidirectional compositing with block skipping.</a> J Xray Sci Technol. 23 (1), 33-44 (2015).</li><li>Janbon, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+the+genome+and+transcriptome+of+Cryptococcus+neoformans+var.+grubii+reveals+complex+RNA+expression+and+microevolution+leading+to+virulence+attenuation.">Analysis of the genome and transcriptome of Cryptococcus neoformans var. grubii reveals complex RNA expression and microevolution leading to virulence attenuation.</a> PLoS Genet. 10 (4), e1004261 (2014).</li><li>Bisson, G. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+use+of+HAART+is+associated+with+decreased+risk+of+death+during+initial+treatment+of+cryptococcal+meningitis+in+adults+in+Botswana.">The use of HAART is associated with decreased risk of death during initial treatment of cryptococcal meningitis in adults in Botswana.</a> J Acquir Immune Defic Syndr. 49 (2), 227-229 (2008).</li><li>van Teeffelen, S., Shaevitz, J. W., Gitai, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Image+analysis+in+fluorescence+microscopy:+bacterial+dynamics+as+a+case+study.">Image analysis in fluorescence microscopy: bacterial dynamics as a case study.</a> Bioessays. 34 (5), 427-436 (2012).</li><li>Granger, D. L., Perfect, J. R., Durack, D. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Virulence+of+Cryptococcus+neoformans.+Regulation+of+capsule+synthesis+by+carbon+dioxide.">Virulence of Cryptococcus neoformans. Regulation of capsule synthesis by carbon dioxide.</a> J Clin Invest. 76 (2), 508-516 (1985).</li></ol>

De capsule is al decennia een belangrijk aandachtspunt van het onderzoek voor zowel mycologen en clinici geïnteresseerd in C. neoformans en cryptococcosis vanwege zijn rol als een belangrijke virulentiefactor voor het pathogene agens oplevert. Met behulp van microscopie te meten van verschillen in capsule grootte tussen stammen en onder verschillende groei kunnen voorwaarden bieden belangrijke informatie over het pathogene agens en de reacties op verschillende stimuli (d.w.z., verschillende milieu-omst...

Invloed zijn op een kwart miljoen mensen per jaar, wat resulteert in meer dan 180.000 doden jaarlijks is Cryptococcus neoformans een pathogene, intracellulaire gist en de verwekker van cryptococcosis1,2, 3. zwaarst getroffen zijn HIV-positieve patiënten in arme landen die niet hebben klaar toegang tot antiretrovirale therapie, waardoor ze zeer gevoelig voor de ziekte4,5,6. Gegevens van de CDC blijkt dat in sub-Saharisch Afrika, C. neoformans meer mensen dan tuberculose jaarlijks en meer elke maand dan een Ebola-uitbraak op record1 doodt. De meest voorkomende route van blootstelling treedt op tegen het inademen van gedroogde sporen die gemeengoed in de omgeving-7 zijn. Bij binnenkomst van de longen, zijn er verschillende Virulentiefactoren die aan het succes van C. neoformans binnen besmette personen bijdragen. De polysaccharide capsule wordt beschouwd als de microbe van primaire virulentiefactor, aangezien acapsular stammen niet virulente8.
De cryptococcal capsule bestaat uit drie onderdelen van het principe: glucuronoxylomannan (GXM), galactoxylomannan (GalXM), en mannoproteins (MPs)9. Terwijl MPs een relatief kleine celwand-geassocieerde onderdeel van de capsule zijn, ze zijn immunogeen en een meestal pro-inflammatoire respons9,10kunnen bevorderen. In tegenstelling, GXM en GalXM maken het grootste deel van de capsule (> 90% van het gewicht) en immunosuppressieve effecten11hebben. Naast de immunomodulerende gevolgen ervan creëert de snelle uitbreiding van de capsule in vivo een mechanische barrière naar inname door gastheer fagocytische cellen (dat wil zeggen, neutrofielen en macrofagen)12. De capsule C. neoformans en de synthese zijn complex, maar overall, verhoogde capsule diameter is gecorreleerd met verhoogde virulentie6,13,14. Gezien dit, is het belangrijk voor C. neoformans onderzoekers om snel en nauwkeurig kwantificeren capsule metingen te kunnen.
Zowel de cel C. neoformans en haar polysaccharide capsule zijn dynamische structuren en wijzigingen weergeven over tijd15. De capsule kunt wijzigen in dichtheid, de grootte en vergadering in reactie op veranderingen in het ontvangende milieu16,17,18. Laag ijzer of nutriëntengehalten, blootstelling aan serum, de menselijke fysiologische pH en verhoogde CO2 zijn bekend tot capsule groei16,18,19,20. Verder, onderzoekers hebben aangetoond structurele veranderingen ten gevolge aanzienlijke verschillen in de immunoreactivity tijdens een infectie, leningen een voordeel aan C. neoformans over de Heerscharen21,22. Dit is bekend omdat de architectuur van de capsule C. neoformans heeft geanalyseerd in een verscheidenheid van manieren. Elektronenmicroscopie, bijvoorbeeld, is gebleken dat de capsule een heterogene matrix met een elektron-dichte binnenlaag onder een buitenste, meer doorlatende laag23 heeft. Lichtverstrooiing en het gebruik van optisch pincet hebben onderzoekers verder het ophelderen van de macromoleculaire eigenschappen24toegestaan. Het analyseren van de resultaten uit beide metingen van statische en dynamische lichtverstrooiing, weten we dat de polysacharide capsule een complexe vertakkende structuur23 heeft. Optisch pincet zijn gebruikt om de test van de stijfheid van de structuur, alsmede het evalueren van de antistof reactiviteit24. Maar is verreweg het vaakst werkzaam analyse van de capsule C. neoformans de meting van de grootte.
Om te kwantificeren capsule grootte, onderzoekers gebruiken wat moet een eenvoudige meting: de lineaire diameter van de capsule. Digitale microscopen worden gebruikt om beelden van meerdere C. neoformans cellen (in het algemeen honderden) gekleurd met Oost-Indische inkt of fluorescente kleurstoffen te vangen. De grootte van elke cel lichaam en omliggende capsule wordt gemeten. De gegevens zijn samengesteld, en de gemiddelde diameter van de capsule wordt berekend door de diameter van de cel lichaam van de diameter van de gehele cel (cel lichaam + capsule) af te trekken. Tot dit punt, zijn deze metingen gedaan handmatig. Terwijl in het algemeen nauwkeurig, heeft deze methode nadelen voor onderzoekers. Grote gegevenssets kunnen nemen dagen of zelfs weken te analyseren met de hand. En omdat deze metingen zijn handmatig gedaan, subjectiviteit en menselijke fouten het resultaat kunnen beïnvloeden.
Geautomatiseerde computationele beeldanalyse is een onmisbaar hulpmiddel geworden voor onderzoekers op vele terreinen van moleculaire celbiologie, waardoor snellere en meer betrouwbare analyse van biologische beelden 25,26,27. Nauwkeurige beeld analysetechnieken zijn nodig om de kwantitatieve gegevens uit wat vaak complexe en enorme gegevenssets zijn. Echter, sommige metingen, met name het meten van C. neoformans capsule, moeilijk geweest te automatiseren. De interface tussen de celwand en capsule, die over het algemeen wordt weergegeven als een donkere ring wanneer beeld door fase contrast microscopie, nauwkeurig te identificeren kan worden lastig op te lossen met behulp van een eenvoudige drempel. Verder, C. neoformans cellen in cultuur de neiging om het groepje samen en nauwkeurige segmentatie van de cellen is noodzakelijk voor nauwkeurige metingen.
Het doel van dit project was om (i) illustreren een van de standaard protocollen voor capsule inductie in C. neoformans, (ii) vergelijken en contrast Oost-Indische inkt en fluorescentie kleuring als ze betrekking hebben om de capsule van de diameter van de metingen, (iii) de ontwikkeling van eenvoudige, computationele methoden voor het meten van de diameter van de capsule met behulp van beelden van de Oost-Indische inkt gekleurd cellen met behulp van de software van de analyse van een afbeelding, en (iv) beoordeling van de voordelen en beperkingen van het meten van de diameter van de capsule handmatig en met behulp van de software automation. Wij vinden dat de kleuring gemakkelijkst, fluorescerende etikettering van de celwand en capsule, terwijl meer tijd in beslag, de meest consistente resultaten tussen experimenten opgeleverd. Echter beide methoden ingeschakeld ons succesvol onderscheiden tussen lab en klinische C. neoformans capsule spanningen vertonen verschillende maten. Verder konden we automatiseren de meting van de diameter van de capsule van de Oost-Indische inkt gekleurde beelden en vond dat dit een levensvatbaar alternatief voor handmatige meting van de capsule.

<table border="0" cellpadding="0" cellspacing="0" width="983">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:451px;">Capsule Induction</td>
			<td style="width:204px;"></td>
			<td style="width:117px;"></td>
			<td style="width:211px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">C. neoformans cells</td>
			<td></td>
			<td></td>
			<td>The clinical lab strain, H99S, was a kind gift from Dr. John Perfect (Duke University).&#160; The clinical strains, B18 and B52, were kind gifts from Dr. Greg Bisson (University of Pennsylania).&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Yeast Peptone Dextrose Broth (YPD)</td>
			<td>Fisher Scientific</td>
			<td>DF0428-17-5</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Phosphate Buffered Saline (PBS)</td>
			<td></td>
			<td></td>
			<td>This is made in the lab using standard recipe (137mM NaCl, 2.7 mM KCl, 10mM Na2HPO4O, 2 mM Kh2PO4O)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">DMEM/high-glucose with L-glutamine, without sodium pyruvate</td>
			<td>GE Life Sciences</td>
			<td>SH30022.01</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">6-well plates</td>
			<td>Falcon</td>
			<td>CL5335-5EA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Shaking incubator</td>
			<td>Thermo Scientific&#160;</td>
			<td></td>
			<td>MaxQ6000</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">CO2 incubator</td>
			<td>Fisher Scientific</td>
			<td></td>
			<td>Isotemp</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Centrifuge</td>
			<td>Thermo Scientific</td>
			<td></td>
			<td>Legend XTR</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Staining</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Microcentrifuge</td>
			<td>Thermo Scientific</td>
			<td></td>
			<td>Legend Micro 21R</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">India ink</td>
			<td>Fisher Scientific</td>
			<td>14-910-56</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Calcofluor white</td>
			<td>Sigma-Aldrich</td>
			<td>18909-100ML-F</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">18B7 mouse anti-GXM antibody conjugated to Alexafluor 488</td>
			<td></td>
			<td></td>
			<td>A kind gift from Dr. Arturo Casadevall (Johns Hopkins University)&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">PBS with 1% Bovine Serum Albumin (BSA)</td>
			<td></td>
			<td></td>
			<td>PBS is the same recipe listed above (line 4) with 1% BSA added and filter sterilized.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Bovine Serum Albumin</td>
			<td>Sigma-Aldrich</td>
			<td>A9418</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Superfrost microscope slides</td>
			<td>Fisher Scientific</td>
			<td>12-550-143</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Glass coverslips</td>
			<td>Corning</td>
			<td>2855-18</td>
			<td>#1.5 thickness</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Clear nail polish or other non-toxic sealant</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Image Acquisition&#160;</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Immersion oil</td>
			<td>Cargille&#160;</td>
			<td>16484</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Light microscope with immersion oil objective</td>
			<td>Zeiss</td>
			<td></td>
			<td>Zeiss Axio A1 with a Plan - NEOFLUAR 100x oil immersion NA 1.30 objective</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Light microscope camera</td>
			<td>Zeiss</td>
			<td></td>
			<td>Zeiss Axiocam ErCD camera</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Confocal microscope with oil immersion objective</td>
			<td>Zeiss</td>
			<td></td>
			<td>LSM 700 laser scanning confocal equipped with a Plan-Apochromat 63X NA 1.4 oil immersion DIC M27 objective.&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Confocal microscope software</td>
			<td>Zen 2009</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Confocal microscope camera</td>
			<td>Nikon</td>
			<td></td>
			<td>Nikon Ti-Eclipse with a Intensilight epifluorescence illuminator (Nikon), CoolSNAP MYO microscope camera (Photometrics), Plan Apo 60x NA 1.40 oil immersion objective (Nikon) and 1.5x magnification changer.&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Widefield imaging software</td>
			<td>Nikon Elements (Nikon)</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Capsule Measurement</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Image editing software</td>
			<td>Photoshop (Adobe)</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Microscope software for manual measurement</td>
			<td>Axiovision (Carl Zeiss)</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Image analysis software for automated meesurement</td>
			<td>Aivia (DRVision Technologies)</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Spreadsheet software</td>
			<td>Excel (Microsoft)</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

size matters: measurement of capsule diameter in cryptococcus neoformans

De polysaccharide capsule van Cryptococcus neoformans is de primaire virulentiefactor en een van de meest algemeen studeerde aspecten van deze pathogene gist. Capsule grootte sterk kan verschillen tussen stammen, heeft de mogelijkheid om snel te groeien wanneer ingevoerd om stressvolle of lage nutriënten voorwaarden en heeft al positief gecorreleerd met de virulentie van de stam. Om deze redenen is de grootte van de capsule van groot belang voor C. neoformans onderzoekers. De groei van de C. neoformans capsule wordt veroorzaakt tijdens de fenotypische test om te helpen begrijpen van de effecten van verschillende behandelingen op de gist of grootte verschillen tussen stammen. Hier beschrijven we een van de standaardmethoden voor capsule inductie en Vergelijk twee aanvaarde methoden van kleuring en het meten van de diameter van de capsule: (i) Oost-Indische inkt, een negatieve vlek, gebruikt in combinatie met de lichte microscopie van conventionele en (ii) mede kleuring met fluorescente kleurstoffen van zowel de celwand en de capsule gevolgd door confocale microscopie. Tot slot laten we zien hoe de meting van de diameter van de capsule van de Oost-Indische inkt gebeitste monsters kan worden geautomatiseerd met behulp van computationele beeldanalyse.

Ter illustratie van de capsule inductie, cel kleuring, imaging en meettechnieken, gebruikten we drie stammen van C. neoformans: het gemeenschappelijk, goed gekarakteriseerd laboratorium stam, H99S30, en twee klinisch geïsoleerde stammen van eerder onbekende capsule diameter, B18 en B5231.
De workflow van de capsule inductie, kleuring en beeldacquisitie met Oost-Indische i...

Watch this Scientific Journal Video about Size Matters: Measurement of Capsule Diameter in Cryptococcus neoformans at JoVE.com

Size Matters: Measurement of Capsule Diameter in Cryptococcus neoformans

Size Matters: Meting van de Diameter van de Capsule in Cryptococcus neoformans

De polysaccharide capsule is de primaire virulentiefactor in Cryptococcus neoformans, en haar grootte correleert met de virulentie van de stam. De diameter van de capsule metingen worden gebruikt bij het testen van de fenotypische en te meten van de therapeutische werking. Hier een standaardmethode van capsule inductie wordt gepresenteerd, en twee methoden van kleuring en het meten van de diameter worden vergeleken.

The polysaccharide capsule of Cryptococcus neoformans is the primary virulence factor and one of the most commonly studied aspects of this pathogenic ...

The overall goal of this procedure is to stain the polysaccharide capsule of C.neoformans strains for the visualization and measurement of the capsule diameter. These methods can help researchers with the induction, imaging, and measurement of capsule size in Cryptococcus neoformans. The main advantage of the staining and imaging techniques is that they are simple, fast, and allow for an accurate measurement of capsule diameter.Visual demonstration of this method is critical as the software steps may be confusing the first time it is used. Diameter of the Cryptococcus neoformans'capsule is often used as a measure of virulence. The ability to automate this process can save significant analysis time.To induce capsule production, first incubate a C.neoformans colony in yeast peptone dextrose broth at 37 degrees Celsius with shaking for 18-36 hours until the culture is in log phase. At the end of the culture, pellet the yeast by centrifugation and wash the yeast three times in PBS. After the last wash, resuspend the yeast at two times 10 to the fifth cells per two milliliters of DMEM concentration and incubate the culture at 37 degrees Celsius and 5%carbon dioxide for 18 hours.The next day, collect the cells by centrifugation and remove all but the last 10 microliters of the supernatant. To stain the yeast with India ink, resuspend the pellet in the remaining supernatant and transfer four microliters of the cell suspension and four microliters of India ink onto a glass microscope slide. Gently mix the resulting solution without creating bubbles.Then place a number 1.5 thickness 13 millimeter glass coverslip over the cell sample and seal the edges with a nontoxic sealant. To stain the yeast with a fluorescent dye, resuspend the overnight culture pellet in 50 microliters of PBS supplemented with 1%bovine serum and incubate the cells in 55-60 microliters of calcofluor-white and Alexa Fluor 488 conjugated capsule monoclonal 18B7 antibody for 30 minutes at 37 degrees Celsius. At the end of the incubation, collect the cells by centrifugation and resuspend the pellet in 10 microliters of PBS plus bovine serum albumin.Then transfer eight microliters of cells onto a glass microscope slide, cover the cell sample with a number 1.5 thickness 13 millimeter glass coverslip and seal the edges with a nontoxic sealant. To stain the yeast with both dyes, first incubate the cells with a fluorescent capsule and cell wall stain as just demonstrated. Then add four microliters of fluorescently-stained cells and four microliters of India ink onto a glass slide and place a sealed coverslip over the fungal cell sample as demonstrated.To image the cells by light microscopy, select the 100X objective and image at least 50 non-overlapping cells per condition with exposure times optimized to maximize the image contrast while minimizing the blur caused by small cell movements. To image the cells by fluorescence microscopy, open the microscope imaging software and select the appropriate excitation and emission wavelengths for the fluorophores used. In the Z stack control panel, select the first last option.Using the fine focus control on the microscope, first focus below the widest point of the cell body of a single yeast cell and the capsules for all of the cells within the current field of view and click set first. Next, use the fine focus control to focus above the widest point of the cell body of the same cell and of the capsule for all of the cells within the current field of view and click set last. Then open the acquisition tab and click start experiment to acquire the Z stack for the current position.To manually measure the capsule and cell diameters, open an appropriate cell measurement program and select the image to be measured. Select measure and use the cursor to draw a straight line through the widest point of the whole cell to measure the total cell diameter. Click measure again and draw a straight line through the cell body to measure the cell body diameter and open the next cell.When all of the cells have been measured, save the images. For automated measurement of the capsule and cell diameters, first open an appropriate image editing program and invert all of the India ink stained cell images. Next, to import both the original and inverted images into the cell measurement software, open the file menu in the measurement program and select import sequence, load image, define sequence manually, dimensions channel, import, and apply.To detect and mask the cell body, select the colony analyzer fluorescence protocol for the first inverted image of interest and click apply. Select the colony analyzer fluorescence protocol again to segment the inverted C.neoformans cell body images from their capsules and click apply again to create a count mask. Right click to rename the count mask cell body and use the cell proliferation protocol on the original image to detect and mask the capsule.Click apply to create a count mask for the original image and rename the count mask capsule. To create a new mask over the original image to partition the adjacent capsules from one another, select capsule partition and capsule for the capsule region. To export the data, click on spreadsheet then click on the export to spreadsheet icon.Select the measurements that you wish to export and then finally save the data. A capsule size increase is apparent in most strains post-induction, although some strains exhibit naturally small capsules. In this representative experiment, a significant difference in capsule size was consistently observed between the largest strain and the two smaller strains.Differences in capsule size can also be detected using fluorescent dyes. Z stack image capture ensures that the maximum capsule and cell body diameter is acquired for each cell. The stacks can then be processed to produce maximum intensity projections for the manual measurement of the yeast cell capsule and cell diameter.There is no significant intra-experiment difference between capsule measurements using either staining method, although a greater inter-experiment variability is observed when using India ink to measure capsule diameters compared to fluorescent dye staining. Significant differences in capsule diameter measurements between different researchers are not typically observed regardless of the method used while small but significant differences in the capsule size can be detected using the automated measurement method. For successful automated measuring, the cells must be in focus, have a medium to large capsule, and not be overly clustered.After watching this video, you should have a good understanding of how to induce the capsule in Cryptococcus neoformans, stain it using either India ink or fluorescent staining, image the capsule, and measure it via automated software.

size-matters-measurement-capsule-diameter-cryptococcus

Research

JoVE Journal

Immunology and Infection

Size Matters: Measurement of Capsule Diameter in Cryptococcus neoformans

Measurement of Cytosolic Ca2+ in Isolated Contractile Lymphatics

Lymphatic vessels comprise a multifunctional transport system that maintains fluid homeostasis, delivers lipids to the central circulation, and acts as a surveillance system for potentially harmful antigens, optimizing mucosal immunity and adaptive immune responses1. Lymph is formed from interstitial fluid that enters blind-ended initial lymphatics, and then is transported against a pressure gradient in larger collecting lymphatics. Each collecting lymphatic is made up of a series of segments called lymphangions, separated by bicuspid valves that prevent backflow. Each lymphangion possesses a contractile cycle that propels lymph against a pressure gradient toward the central circulation2. This phasic contractile pattern is analogous to the cardiac cycle, with systolic and diastolic phases, and with a lower contraction frequency4. In addition, lymphatic smooth muscle generates tone and displays myogenic constriction and dilation in response to increases and decreases in luminal pressure, respectively5. A hybrid of molecular mechanisms that support both the phasic and tonic contractility of lymphatics are thus proposed.
Contraction of smooth muscle is generally regulated by the cytosolic Ca2+ concentration ([Ca2+]i) plus sensitivity to Ca2+, of the contractile elements in response to changes in the environment surrounding the cell6. [Ca2+]i is determined by the combination of the movement of Ca2+ through plasma membrane ligand or voltage gated Ca2+ channels and the release and uptake of Ca2+ from internal stores. Cytosolic Ca2+ binds to calmodulin and activates enzymes such as myosin light chain (MLC) kinase (MLCK), which in turn phosphorylates MLC leading to actin-myosin-mediated contraction8. However, the sensitivity of this pathway to Ca2+ can be regulated by the MLC phosphatase (MLCP)9. MLCP activity is regulated by Rho kinase (ROCK) and the myosin phosphatase inhibitor protein CPI-17.
Here, we present a method to evaluate changes in [Ca2+]i over time in isolated, perfused lymphatics in order to study Ca2+-dependent and Ca2+-sensitizing mechanisms of lymphatic smooth muscle contraction. Using isolated rat mesenteric collecting lymphatics we studied stretch-induced changes in [Ca2+]i and contractile activity. The isolated lymphatic model offers the advantage that pressure, flow, and the chemical composition of the bath solution can be tightly controlled. [Ca2+]i was determined by loading lymphatics with the ratiometric, Ca2+-binding dye Fura-2. These studies will provide a new approach to the broader problem of studying the different molecular mechanisms that regulate phasic contractions versus tonic constriction in lymphatic smooth muscle.

Measurement of Cytosolic Ca2+ in Isolated Contractile Lymphatics

We introduce an approach to evaluate the cytosolic Ca2+ concentration in isolated lymphatics to study Ca2+-dependent and Ca2+-sensitizing mechanisms of lymphatic smooth muscle contraction.

Meting van cytosolische Ca 2 + In geïsoleerde contractiele lymphatische

Lymphatic vessels comprise a multifunctional transport system that maintains fluid homeostasis, delivers lipids to the central circulation, and acts as a ...

Measurement of &#947;HV68 Infection in Mice

&gamma;-Herpesviruses (&gamma;-HVs) are notable for their ability to establish latent infections of lymphoid cells1. The narrow host range of human &gamma;-HVs, such as EBV and KSHV, has severely hindered detailed pathogenic studies. Murine &gamma;-herpesvirus 68 (&gamma;HV68) shares extensive genetic and biological similarities with human &gamma;-HVs and is a natural pathogen of murid rodents2. As such, evaluation of &gamma;HV68 infection of mice inbred strains at different stages of viral infection provides an important model for understanding viral lifecycle and pathogenesis during &gamma;-HVs infection.
Upon intranasal inoculation, &gamma;HV68 infection results in acute viremia in the lung that is later resolved into a latent infection of splenocytes and other cells, which may be reactivated throughout the life of the host3,4. In this protocol, we will describe how to use the plaque assay to assess infectious virus titer in the lung homogenates on Vero cell monolayers at the early stage (5 - 7 days) of post-intranasal infection (dpi). While acute infection is largely cleared 2 - 3 weeks postinfection, a latent infection of &gamma;HV68 is established around 14 dpi and maintained later on in the spleen of the mice. Latent infection usually affects a very small population of cells in the infected tissues, whereby the virus stays dormant and shuts off most of its gene expression. Latently-infected splenocytes spontaneously reactivate virus upon explanting into tissue culture, which can be recapitulated by an infectious center (IC) assay to determine the viral latent load. To further estimate the amount of viral genome copies in the acutely and/or latently infected tissues, quantitative real-time PCR (qPCR) is used for its maximal sensitivity and accuracy. The combined analyses of the results of qPCR and plaque assay, and/or IC assay will reveal the spatiotemporal profiles of viral replication and infectivity in vivo.

&#947;-Herpesviruses (&#947;-HVs) establish life-long persistency in their host. Infection of mice with &#947;-HV68 provides a genetically tractable in vivo model for the characterization of the lifecycle/pathogenesis of &#947;HVs. This protocol describes the detection and quantitation of &#947;HV68 infection at acute and latent stages following infection by plaque-forming, infectious center, and qPCR assays.

Meting van γHV68 infectie in Muizen

&gamma;-Herpesviruses (&gamma;-HVs) are notable for their ability to establish latent infections of lymphoid cells1. The narrow host range of human ...

Quantitative Measurement of the Immune Response and Sleep in Drosophila

A complex interaction between the immune response and host behavior has been described in a wide range of species. Excess sleep, in particular, is known to occur as a response to infection in mammals 1 and has also recently been described in Drosophila melanogaster2. It is generally accepted that sleep is beneficial to the host during an infection and that it is important for the maintenance of a robust immune system3,4. However, experimental evidence that supports this hypothesis is limited4, and the function of excess sleep during an immune response remains unclear. We have used a multidisciplinary approach to address this complex problem, and have conducted studies in the simple genetic model system, the fruitfly Drosophila melanogaster. We use a standard assay for measuring locomotor behavior and sleep in flies, and demonstrate how this assay is used to measure behavior in flies infected with a pathogenic strain of bacteria. This assay is also useful for monitoring the duration of survival in individual flies during an infection. Additional measures of immune function include the ability of flies to clear an infection and the activation of NF&kappa;B, a key transcription factor that is central to the innate immune response in Drosophila. Both survival outcome and bacterial clearance during infection together are indicators of resistance and tolerance to infection. Resistance refers to the ability of flies to clear an infection, while tolerance is defined as the ability of the host to limit damage from an infection and thereby survive despite high levels of pathogen within the system5. Real-time monitoring of NF&kappa;B activity during infection provides insight into a molecular mechanism of survival during infection. The use of Drosophila in these straightforward assays facilitates the genetic and molecular analyses of sleep and the immune response and how these two complex systems are reciprocally influenced.

Quantitative Measurement of the Immune Response and Sleep in Drosophila

To understand a link between the immune response and behavior, we describe a method to measure locomotor behavior in Drosophila during bacterial infection as well as the ability of flies to mount an immune response by monitoring survival, bacterial load, and real-time activity of a key regulator of innate immunity, NF&kappa;B.

Kwantitatieve meting van de immuunrespons en Sleep in<em&gt; Drosophila</em

A complex interaction between the immune response and  host behavior has been described in a wide range of species. Excess sleep, in  particular, is known ...

Measurement of Tactile Allodynia in a Murine Model of Bacterial Prostatitis

Uropathogenic Escherichia coli (UPEC) are pathogens that play an important role in urinary tract infections and bacterial prostatitis1. We have recently shown that UPEC have an important role in the initiation of chronic pelvic pain2, a feature of Chronic prostatitis/Chronic pelvic pain syndrome (CP/CPPS)3,4. Infection of the prostate by clinically relevant UPEC can initiate and establish chronic pain through mechanisms that may involve tissue damage and the initiation of mechanisms of autoimmunity5.
A challenge to understanding the pathogenesis of UPEC in the prostate is the relative inaccessibility of the prostate gland to manipulation. We utilized a previously described intraurethral infection method6 to deliver a clinical strain of UPEC into male mice thereby establishing an ascending infection of the prostate. Here, we describe our protocols for standardizing the bacterial inoculum7 as well as the procedure for catheterizing anesthetized male mice for instillation of bacteria.
CP/CPPS is primarily characterized by the presence of tactile allodynia4. Behavior testing was based on the concept of cutaneous hyperalgesia resulting from referred visceral pain8-10. An irritable focus in visceral tissues reduces cutaneous pain thresholds allowing for an exaggerated response to normally non-painful stimuli (allodynia). Application of normal force to the skin result in abnormal responses that tend to increase with the intensity of the underlying visceral pain. We describe methodology in NOD/ShiLtJ mice that utilize von Frey fibers to quantify tactile allodynia over time in response to a single infection with UPEC bacteria.

Infection of the prostate may be a contributing factor in mediating pelvic pain in chronic prostatitis. We describe the procedure for preparation of standardized bacterial inoculum, instillation of bacteria into the urethra of male mice and methodology for measuring tactile allodynia in mice over time.

Meting van Tactiele allodynie in een muizenmodel van bacteriële prostatitis

Uropathogenic Escherichia coli (UPEC) are pathogens that play an important role in urinary tract infections and bacterial prostatitis1. We have recently ...

Visualizing Non-lytic Exocytosis of Cryptococcus neoformans from Macrophages Using Digital Light Microscopy

Many aspects of the infection of macrophages by Cryptococcus neoformans have been extensively studied and well defined. However, one particular interaction that is not clearly understood is non-lytic exocytosis. In this process, yeast cells are released into the extracellular space by a poorly understood mechanism that leaves both the macrophage and Cn viable. Here, we describe how to follow a large number of individually infected macrophages for a 24 hr infection period by time-lapsed microscopy. Infected macrophages are housed in a heating chamber with a CO2 atmosphere attached to a microscope that provides the same conditions as a cell-culture incubator. Live digital microscopy can provide information about the dynamic interactions between a host and pathogen that is not available from static images. Being able to visualize each infected cell can provide clues as to how macrophages handle fungal infections, and vice versa. This technique is a powerful tool in studying the dynamics that are behind a complex phenomenon.

Visualizing Non-lytic Exocytosis of Cryptococcus neoformans from Macrophages Using Digital Light Microscopy

We describe how to visualize macrophage-C. neoformans (Cn) interactions in real time, with specific emphasis on the process of non-lytic exocytosis using digital light microscopy. Using this technique individually infected macrophages can be studied to ascertain various aspects of this phenomenon.

Visualiseren Non-lytische Exocytosis van<em&gt; Cryptococcus neoformans</em&gt; Van Macrofagen behulp Digital Light Microscopy

Many aspects of the infection of macrophages by Cryptococcus neoformans have been extensively studied and well defined. However, one particular ...

Macrophage Cholesterol Depletion and Its Effect on the Phagocytosis of Cryptococcus neoformans

Cryptococcosis is a life-threatening infection caused by pathogenic fungi of the genus Cryptococcus. Infection occurs upon inhalation of spores, which are able to replicate in the deep lung. Phagocytosis of Cryptococcus by macrophages is one of the ways that the disease is able to spread into the central nervous system to cause lethal meningoencephalitis. Therefore, study of the association between Cryptococcus and macrophages is important to understanding the progression of the infection. The present study describes a step-by-step protocol to study macrophage infectivity by C. neoformansin vitro. Using this protocol, the role of host sterols on host-pathogen interactions is studied. Different concentrations of methyl--cyclodextrin (MCD) were used to deplete cholesterol from murine reticulum sarcoma macrophage-like cell line J774A.1. Cholesterol depletion was confirmed and quantified using both a commercially available cholesterol quantification kit and thin layer chromatography. Cholesterol depleted cells were activated using Lipopolysacharide (LPS) and Interferon gamma (IFN&#947;) and infected with antibody-opsonized Cryptococcus neoformans wild-type H99 cells at an effector-to-target ratio of 1:1. Infected cells were monitored after 2 hr of incubation with C. neoformans and their phagocytic index was calculated. Cholesterol depletion resulted in a significant reduction in the phagocytic index. The presented protocols offer a convenient method to mimic the initiation of the infection process in a laboratory environment and study the role of host lipid composition on infectivity.

Macrophage Cholesterol Depletion and Its Effect on the Phagocytosis of Cryptococcus neoformans

In this article, a protocol for infection of macrophages with Cryptococcus neoformans is described. Also, a method for sterol depletion from the macrophages is explained. These protocols provide a guide to study fungal infections in vitro and examine the role of sterols in such infections.

Macrofagen Cholesterol Uitputting en het effect daarvan op de Fagocytose van<em&gt; Cryptococcus neoformans</em

Cryptococcosis is a life-threatening infection caused by pathogenic fungi of the genus Cryptococcus. Infection occurs upon inhalation of spores, which are ...

Biolistic Transformation of a Fluorescent Tagged Gene into the Opportunistic Fungal Pathogen Cryptococcus neoformans

The basidiomycete Cryptococcus neoformans, an invasive opportunistic pathogen of the central nervous system, is the most frequent cause of fungal meningitis worldwide resulting in more than 625,000 deaths per year worldwide.&#160;Although electroporation has been developed for the transformation of plasmids in Cryptococcus, only&#160;biolistic&#160;delivery provides&#160;an effective means to transform&#160;linear&#160;DNA&#160;that can be integrated into the genome by homologous recombination.&#160;
Acetate has been shown to be a major fermentation product during cryptococcal infection, but the significance of this is not yet known.&#160;A bacterial pathway composed of the enzymes xylulose-5-phosphate/fructose-6-phosphate phosphoketolase (Xfp) and acetate kinase (Ack) is one of three potential pathways for acetate production in C. neoformans. Here, we demonstrate the biolistic transformation of a construct, which has the gene encoding Ack fused to the fluorescent tag mCherry, into&#160;C. neoformans. We then confirm integration of the ACK-mCherry fusion into the&#160;ACK&#160;locus.

Biolistic Transformation of a Fluorescent Tagged Gene into the Opportunistic Fungal Pathogen Cryptococcus neoformans

Biolistic transformation is a method used to generate stable integration of DNA into the genome of the opportunistic pathogen Cryptococcus neoformans through homologous recombination. We will demonstrate biolistic transformation of a construct, which has the gene encoding acetate kinase fused to the fluorescent tag mCherry into&#160;C. neoformans.

Biolistische Transformatie van een TL Tagged Gene in de Opportunistische schimmelpathogeen<em&gt; Cryptococcus neoformans</em

The basidiomycete Cryptococcus neoformans, an invasive opportunistic pathogen of the central nervous system, is the most frequent cause of fungal ...

Measurement of In Vitro Integration Activity of HIV-1 Preintegration Complexes

HIV-1 envelope proteins engage cognate receptors on the target cell surface, which leads to viral-cell membrane fusion followed by the release of the viral capsid (CA) core into the cytoplasm. Subsequently, the viral Reverse Transcriptase (RT), as part of a namesake nucleoprotein complex termed the Reverse Transcription Complex (RTC), converts the viral single-stranded RNA genome into a double-stranded DNA copy (vDNA). This leads to the biogenesis of another nucleoprotein complex, termed the pre-integration complex (PIC), composed of the vDNA and associated virus proteins and host factors. The PIC-associated viral integrase (IN) orchestrates the integration of the vDNA into the host chromosomal DNA in a temporally and spatially regulated two-step process. First, the IN processes the 3&#39; ends of the vDNA in the cytoplasm and, second, after the PIC traffics to the nucleus, it mediates integration of the processed vDNA into the chromosomal DNA. The PICs isolated from target cells acutely infected with HIV-1 are functional in vitro, as they are competent to integrate the associated vDNA into an exogenously added heterologous target DNA. Such PIC-based in vitro integration assays have significantly contributed to delineating the mechanistic details of retroviral integration and to discovering IN inhibitors. In this report, we elaborate upon an updated HIV-1 PIC assay that employs a nested real-time quantitative Polymerase Chain Reaction (qPCR)-based strategy for measuring the in vitro integration activity of isolated native PICs.

Measurement of In Vitro Integration Activity of HIV-1 Preintegration Complexes

This report describes an in vitro assay for measuring the human immunodeficiency virus type 1 (HIV-1) preintegration complex (PIC)-associated integration activity in the cytoplasmic extracts of acutely infected cells. The integration of PIC-associated HIV-1 DNA into heterologous target DNA is quantified by using a nested real-time polymerase chain reaction strategy.

Meting van<em&gt; In Vitro</em&gt; Integratie activiteit van HIV-1 Preintegration Complexen

HIV-1 envelope proteins engage cognate receptors on the target cell surface, which leads to viral-cell membrane fusion followed by the release of the ...

Automated Measurement of Cryptococcal Species Polysaccharide Capsule and Cell Body

The purpose of this technique is to provide a consistent, accurate, and manageable process for large numbers of polysaccharide capsule measurements.
First, a threshold image is generated based on intensity values uniquely calculated for each image. Then, circles are detected based on contrast between the object and background using the well-established Circle Hough Transformation (CHT) algorithm. Finally, the detected cell capsules and bodies are matched according to center coordinates and radius size, and data is exported to the user in a manageable spreadsheet.
The advantages of this technique are simple but significant. First, because these calculations are performed by an algorithm rather than a human both accuracy and reliability are increased. There is no decline in accuracy or reliability regardless of how many samples are analyzed. Second, this approach establishes a potential standard operating procedure for the Cryptococcus field instead of the current situation where capsule measurement varies by lab. Third, given that manual capsule measurements are slow and monotonous, automation allows rapid measurements on large numbers of yeast cells that in turn facilitates high throughput data analysis and increasingly powerful statistics.
The major limitations of this technique come from how the algorithm functions. First, the algorithm will only generate circles. While Cryptococcus cells and their capsules take on a circular morphology, it would be difficult to apply this technique to non-circular object detection. Second, due to how circles are detected the CHT algorithm can detect enormous pseudo-circles based on the outer edges of several clustered circles. However, any misrepresented cell bodies caught within the pseudo-circle can be easily detected and removed from the resulting data sets.
This technique is meant for measuring the circular polysaccharide capsules of Cryptococcus species based on India Ink bright field microscopy; though it could be applied to other contrast based circular object measurements.

Automated Measurement of Cryptococcal Species Polysaccharide Capsule and Cell Body

This technique describes an automated batch image processor designed to measure polysaccharide capsule and body radii. While initially designed for Cryptococcus neoformans capsule measurements the automated image processor can also be applied to other contrast based detection of circular objects.

Geautomatiseerde meting van Cryptococcal soorten Polysaccharide Capsule en cel lichaam

The purpose of this technique is to provide a consistent, accurate, and manageable process for large numbers of polysaccharide capsule measurements.
...

High-throughput Measurement of Plasma Membrane Resealing Efficiency in Mammalian Cells

In their physiological environment, mammalian cells are often subjected to mechanical and biochemical stresses that result in plasma membrane damage. In response to these damages, complex molecular machineries rapidly reseal the plasma membrane to restore its barrier function and maintain cell survival. Despite 60 years of research in this field, we still lack a thorough understanding of the cell resealing machinery. With the goal of identifying cellular components that control plasma membrane resealing or drugs that can improve resealing, we have developed a fluorescence-based high-throughput assay that measures the plasma membrane resealing efficiency in mammalian cells cultured in microplates. As a model system for plasma membrane damage, cells are exposed to the bacterial pore-forming toxin listeriolysin O (LLO), which forms large 30-50 nm diameter proteinaceous pores in cholesterol-containing membranes. The use of a temperature-controlled multi-mode microplate reader allows for rapid and sensitive spectrofluorometric measurements in combination with brightfield and fluorescence microscopy imaging of living cells. Kinetic analysis of the fluorescence intensity emitted by a membrane impermeant nucleic acid-binding fluorochrome reflects the extent of membrane wounding and resealing at the cell population level, allowing for the calculation of the cell resealing efficiency. Fluorescence microscopy imaging allows for the enumeration of cells, which constitutively express a fluorescent chimera of the nuclear protein histone 2B, in each well of the microplate to account for potential variations in their number and allows for eventual identification of distinct cell populations. This high-throughput assay is a powerful tool expected to expand our understanding of membrane repair mechanisms via screening for host genes or exogenously added compounds that control plasma membrane resealing.

Here we describe a high-throughput fluorescence-based assay that measures the plasma membrane resealing efficiency through fluorometric and imaging analyses in living cells. This assay can be used for screening drugs or target genes that regulate plasma membrane resealing in mammalian cells.

High-throughput meting van plasmamembraan opnieuw verzegelen efficiëntie bij zoogdiercellen

In their physiological environment, mammalian cells are often subjected to mechanical and biochemical stresses that result in plasma membrane damage. In ...