This work was financed by Fundo Europeu de Desenvolvimento Regional (FEDER) funds through the COMPETE 2020 - Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020, and by Portuguese funds through FCT - Funda&#231;&#227;o para a Ci&#234;ncia e a Tecnologia/Minist&#233;rio da Ci&#234;ncia, Tecnologia e Ensino Superior in the framework of the project POCI-01-0145-FEDER-028779 and the grant SFRH/BD/99715/2014 (CF).

1. Cyanobacterial released carbohydrate polymer isolation
<ol>
	<li>Polymer isolation and removal of contaminants 
	<ol>
		<li>Cultivate the cyanobacterial strain under standard conditions [e.g., 30 &#176;C under a 12 h light (50 &#956;E m&#8722;2s&#8722;1)/12 h dark regimen, with orbital shaking at 150 rpm]. Measure growth using standard protocols [e.g., optical density at 730 nm (OD730nm), chlorophyll a, dry-weight, etc.], then measure the production of released polysaccharides according to the phenol-sulfuric acid method16.</li>
		<li>Transfer the culture into dialysis membranes (12-14 kDa of molecular weight cut-off) and dialyze against a minimum of 10 volumes of deionized water for 24 h with continuous stirring. 
		NOTE: Depending on the volume of culture to dialyze and medium composition, it may be necessary to change the dialysis water.</li>
		<li>Centrifuge the culture at 15,000 x g for 15 min at 4 &#176;C. Transfer the supernatant to a new vial and discard the pellet (cells).</li>
		<li>Centrifuge again at 20,000 x g for 15 min at 4 &#176;C to remove contaminants such as cell wall debris or lipopolysaccharides (LPS).</li>
		<li>Transfer the supernatant to a glass beaker and discard the pellet.</li>
	</ol>
	</li>
	<li>Precipitation of the polymer
	<ol>
		<li>Add 2 volumes of 96% ethanol to the supernatant.</li>
		<li>Incubate the suspension at 4 &#176;C, at least overnight.</li>
		<li>Polymer recovery
		<ol>
			<li>For small or not visible amounts of precipitated polymer: centrifuge the suspension at 13,000 x g for 25 min at 4 &#176;C. Discard the supernatant and resuspend the pellet in 1 mL or 2 mL of autoclaved deionized water. Transfer the aqueous suspension to a vial. 
			CAUTION: The supernatant should be discarded gently, as it can become easily resuspended.</li>
			<li>For visible/large amounts of precipitated polymer: collect the precipitated polymer with sterile metal forceps to a vial. Squeeze the polymer and discard the excess ethanol.</li>
		</ol>
		</li>
		<li>Optional: depending on the degree of polymer purification required, repeat the precipitation step with 96% ethanol after resuspension of the polymers in deionized water.</li>
	</ol>
	</li>
	<li>Lyophilization of the polymer 
	<ol>
		<li>Keep the vials with the precipitated polymer at -80 &#176;C, at least overnight.</li>
		<li>Freeze-dry (lyophilize) the polymer for at least 48 h (do not let the suspension defrost before freeze-drying).</li>
		<li>Store the dried polymer at room temperature (RT) until further use. 
		NOTE: Storing the polymer in a desiccator is advisable, as it can absorb water over time.</li>
	</ol>
	</li>
</ol>
2. Cyanobacterial exoproteome isolation
<ol>
	<li>Medium concentration
	<ol>
		<li>Cultivate cyanobacteria under standard conditions [e.g., 30 &#176;C under a 12 h light (50 &#956;E m&#8722;2s&#8722;1)/12 h dark regimen, with orbital shaking at 150 rpm]. Monitor the cyanobacterium growth using standard procedures (e.g., OD730nm, chlorophyll a, dry-weight, etc.).</li>
		<li>Centrifuge the cultures at 4,000 x g, for 10 min at RT.</li>
		<li>Transfer the supernatant to a flask and discard the cell pellet.</li>
		<li>Filter the decanted medium through a 0.2 &#956;m pore size filter. 
		NOTE: The protocol can be paused here for a short time period, if the medium is kept at 4 &#176;C.</li>
		<li>Concentrate the medium approximately 500x (considering the initial volume of filtered medium), using centrifugal concentrators with a nominal molecular weight cut-off of 3 kDa. Centrifugation should be operated at 4,000 x g (maximum 1 h per centrifugation round) at 15 &#176;C. 
		CAUTION: For the majority of concentrator brands, the filter device needs to be rinsed by centrifugation with ultrapure water before use. Once the filter is wet, do not let it dry out. Leave enough fluid on the reservoir when the device is not being used. 
		NOTE: Reducing the centrifugation temperature to 4 &#176;C may be helpful if the aim is to study protein activity, though it will increase the time necessary for sample concentration. The protocol can be paused between centrifugation steps for short time periods if the medium is kept at 4 &#176;C.</li>
		<li>Rinse the walls of the filter device sample reservoir with the concentrated sample and transfer the content to a microcentrifuge tube.</li>
		<li>Perform an additional washing step of the filter device sample reservoir with autoclaved culture medium to ensure maximal exoproteome recovery. 
		NOTE: To quantify the percentage of recovery, follow the specific manufacturer&#8217;s instructions.</li>
		<li>Store the exoproteome samples at -20 &#176;C until further use. 
		NOTE: Addition of protease inhibitors is recommended for long-term storage.</li>
	</ol>
	</li>
	<li>Analysis of the exoproteome
	<ol>
		<li>Quantify the protein content by BCA protein assay in 96-well plate according to the manufacturer&#8217;s instructions.</li>
		<li>Separate the proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), using standard staining protocols (e.g., Coomassie blue, silver staining).</li>
		<li>Cut out the bands/gel regions of interest and collect them in different microcentrifuge tubes containing appropriate volumes of ultra-pure water.</li>
		<li>Proceed with identification and analysis of the proteins by mass spectrometry.</li>
	</ol>
	</li>
</ol>

<ol>
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J., Liu, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+of+polysaccharides+from+cyanobacteria+Nostoc+commune+and+their+antioxidant+activities.">Preparation of polysaccharides from cyanobacteria Nostoc commune and their antioxidant activities.</a> Carbohydrate Polymers. 99, 553-555 (2014).</li><li>Ozturk, S., Aslim, B., Suludere, Z., Tan, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metal+removal+of+cyanobacterial+exopolysaccharides+by+uronic+acid+content+and+monosaccharide+composition.">Metal removal of cyanobacterial exopolysaccharides by uronic acid content and monosaccharide composition.</a> Carbohydrate Polymers. 101, 265-271 (2014).</li><li>Han, P. 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=Emulsifying,+flocculating,+and+physicochemical+properties+of+exopolysaccharide+produced+by+cyanobacterium+Nostoc+flagelliforme.">Emulsifying, flocculating, and physicochemical properties of exopolysaccharide produced by cyanobacterium Nostoc flagelliforme.</a> Applied Biochemistry and Biotechnology. 172 (1), 36-49 (2014).</li><li>Leite, J. 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=Cyanobacterium&#8208;Derived+Extracellular+Carbohydrate+Polymer+for+the+Controlled+Delivery+of+Functional+Proteins.">Cyanobacterium&#8208;Derived Extracellular Carbohydrate Polymer for the Controlled Delivery of Functional Proteins.</a> Macromolecular Bioscience. 17 (2), 1600206 (2017).</li><li>Estevinho, B. N., 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=Application+of+a+cyanobacterial+extracellular+polymeric+substance+in+the+microencapsulation+of+vitamin+B12.">Application of a cyanobacterial extracellular polymeric substance in the microencapsulation of vitamin B12.</a> Powder Technology. 343, 644-651 (2019).</li><li>Klock, J. H., Wieland, A., Seifert, R., Michaelis, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extracellular+polymeric+substances+(EPS)+from+cyanobacterial+mats:+characterisation+and+isolation+method+optimisation.">Extracellular polymeric substances (EPS) from cyanobacterial mats: characterisation and isolation method optimisation.</a> Marine Biology. 152 (5), 1077-1085 (2007).</li><li>Delattre, C., Pierre, G., Laroche, C., Michaud, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production,+extraction+and+characterization+of+microalgal+and+cyanobacterial+exopolysaccharides.">Production, extraction and characterization of microalgal and cyanobacterial exopolysaccharides.</a> Biotechnology Advances. 34 (7), 1159-1179 (2016).</li><li>Costa, T. 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=Secretion+systems+in+gram-negative+bacteria:+structural+and+mechanistic+insights.">Secretion systems in gram-negative bacteria: structural and mechanistic insights.</a> Nature Reviews Microbiology. 13 (6), 343-359 (2015).</li><li>Roier, S., Zingl, F. G., Cakar, F., Schild, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacterial+outer+membrane+vesicle+biogenesis:+a+new+mechanism+and+its+implications.">Bacterial outer membrane vesicle biogenesis: a new mechanism and its implications.</a> Microbial Cell. 3 (6), 257-259 (2016).</li><li>Sergeyenko, T. V., Los, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+secreted+proteins+of+the+cyanobacterium+Synechocystis+sp.+strain+PCC+6803.">Identification of secreted proteins of the cyanobacterium Synechocystis sp. strain PCC 6803.</a> FEMS Microbiology Letters. 193 (2), 213-216 (2000).</li><li>Oliveira, 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+versatile+TolC-like+Slr1270+in+the+cyanobacterium+Synechocystis+sp.+PCC+6803.">The versatile TolC-like Slr1270 in the cyanobacterium Synechocystis sp. PCC 6803.</a> Environmental Microbiology. 18 (2), 486-502 (2016).</li><li>Flores, C., 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+alternative+sigma+factor+SigF+is+a+key+player+in+the+control+of+secretion+mechanisms+in+Synechocystis+sp.+PCC+6803.">The alternative sigma factor SigF is a key player in the control of secretion mechanisms in Synechocystis sp. PCC 6803.</a> Environmental Microbiology. 21 (1), 343-359 (2018).</li><li>Dubois, M., Gilles, K. A., Hamilton, J. K., Rebers, P. 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S., Kannaujiya, V. K., Sinha, R. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cyanobacterial+extracellular+polysaccharide+sheath+pigment,+scytonemin:+A+novel+multipurpose+pharmacophore.">Cyanobacterial extracellular polysaccharide sheath pigment, scytonemin: A novel multipurpose pharmacophore.</a> Marine Glycobiology. , 343-358 (2016).</li><li>Nguyen, A. T. B., 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=Performances+of+different+protocols+for+exocellular+polysaccharides+extraction+from+milk+acid+gels:+Application+to+yogurt.">Performances of different protocols for exocellular polysaccharides extraction from milk acid gels: Application to yogurt.</a> Food Chemistry. 239, 742-750 (2018).</li><li>Jamshidian, H., Shojaosadati, S. A., Mousavi, S. M., Soudi, M. R., Vilaplana, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Implications+of+recovery+procedures+on+structural+and+rheological+properties+of+schizophyllan+produced+from+date+syrup.">Implications of recovery procedures on structural and rheological properties of schizophyllan produced from date syrup.</a> International Journal of Biological Macromolecules. 105, 36-44 (2017).</li><li>Couto, N., Schooling, S. R., Dutcher, J. R., Barber, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proteome+profiles+of+outer+membrane+vesicles+and+extracellular+matrix+of+Pseudomonas+aeruginosa+biofilms.">Proteome profiles of outer membrane vesicles and extracellular matrix of Pseudomonas aeruginosa biofilms.</a> Journal of Proteome Research. 14 (10), 4207-4222 (2015).</li></ol>

The authors have nothing to disclose.

To better understand bacterial secretion mechanisms and study the released products, it is of extreme importance to demonstrate the efficient isolation and analysis of the biomolecules present in the extracellular bacterial environment (such as released carbohydrate polymers and proteins).
Cyanobacterial extracellular carbohydrate polymers are extremely complex, mainly due to the number and proportion of different monosaccharides that constitute their composition1. The ...

Cyanobacteria are widely recognized as prolific sources of natural products with promising biotechnological/biomedical applications. Therefore, understanding cyanobacterial secretion mechanisms and optimization of the extraction/recovery methods are essential to implement cyanobacteria as efficient microbial cell factories.
Many cyanobacterial strains are able to produce extracellular polymeric substances (EPS), mainly formed by heteropolysaccharides, that remain associated to the cell surface or are released into the medium1. These released carbohydrate polymers have distinct features compared to those from other bacteria, which make them suitable for a wide range of applications (e.g., antivirals2, immunostimulatory3, antioxidant4, metal-chelating5, emulsifying6, and drug delivery agents7,8). Methodology for the isolation of these polymers largely contributes&#160;not only to improved yield but also to increased purity and the specific physical properties of the polymer obtained9. A vast majority of these methods for isolation of the polymers rely on precipitation strategies from the culture medium that are easily accomplished due to the polymer&#8217;s strong anionic nature9,10. In addition, removal of the solvents used in the precipitation step can be rapidly achieved by evaporation and/or lyophilization. Depending on the foreseen application, different steps can be coupled either after or before polymer precipitation in order to tailor the final product, which include trichloroacetic acid (TCA) treatment, filtration, or size exclusion chromatography (SEC) column purification10.
Cyanobacteria are also able to secrete a wide range of proteins through pathways dependent on membrane transporters (classical)11 or mediated by vesicles (non-classical)12. Therefore, analysis of the cyanobacterial exoproteome constitutes an essential tool, both to understand/manipulate cyanobacterial protein secretion mechanisms and understand the specific extracellular function of these proteins. Reliable isolation and analysis of exoproteomes require the concentration of the extracellular milieu, since the abundance of secreted proteins is relatively low. In addition, other physical or chemical steps (e.g., centrifugation, filtration, or protein precipitation) may optimize the quality of the exoproteome obtained, enriching the protein content13, and avoiding the presence of contaminants (e.g., pigments, carbohydrates, etc.)14,15 or the predominance of intracellular proteins in the samples. However, some of these steps may also restrict the set of proteins that can be detected, leading to a biased analysis.
This work describes efficient protocols for the isolation of released carbohydrate polymers and exoproteomes from cyanobacteria culture media. These protocols can be easily adapted to the study&#8217;s specific objectives and user needs, while maintaining the basic steps presented here.

<table><tbody><tr><td>Dialysis membranes</td><td>Medicell Membranes Ltd&amp;nbsp;</td><td>DTV.12000.07</td><td>Visking Tubing Size 7, Dia 23.8 mm, Width 39-41 mm 30m Roll&amp;nbsp;</td></tr><tr><td>Ethanol 96%</td><td>AGA - &amp;Aacute;lcool e G&amp;eacute;neros Alimentares, S.A.</td><td>4.000.02.02.00</td><td>Fermentation ethyl alcohol 96% AGA</td></tr><tr><td>PES Filter 0.2 &amp;mu;m</td><td>Fisher Scientific, Lda</td><td>15206869</td><td>Syringe filter polystyrene 33MM 0.2&amp;micro;M STR&amp;nbsp;</td></tr><tr><td>Amicon Ultra-15, Ultracel-3K</td><td>Merck Millipore Ltd.</td><td>UFC900324</td><td>Centrifugal filters with a nominal molecular weight cut-off of 3 kDa</td></tr><tr><td>Thermo Scientific&amp;nbsp;Pierce BCA Protein Assay</td><td>Fisher Scientific, Lda</td><td>10741395</td><td>Green-to-blue, precise, detergent-compatible assay reagent to measure total protein concentration</td></tr><tr><td>Brillant Blue G Colloidal Concentrate&amp;nbsp;</td><td>Sigma Aldrich Qu&amp;iacute;mica SL</td><td>B2025-1EA</td><td>Coomassie blue&amp;nbsp;</td></tr></tbody></table>

looking outwards: isolation of cyanobacterial released carbohydrate polymers and proteins

Cyanobacteria can actively secrete a wide range of biomolecules into the extracellular environment, such as heteropolysaccharides and proteins. The identification and characterization of these biomolecules can improve knowledge about their secretion pathways and help to manipulate them. Furthermore, some of these biomolecules are also interesting in terms of biotechnological applications. Described here are two protocols for easy and rapid isolation of cyanobacterial released carbohydrate polymers and proteins. The method for isolation of released carbohydrate polymers is based on conventional precipitation techniques of polysaccharides in aqueous solutions using organic solvents. This method preserves the characteristics of the polymer and simultaneously avoids the presence of contaminants from cell debris and culture medium. At the end of the process, the lyophilized polymer is ready to be used or characterized or can be subjected to further rounds of purification, depending on the final intended use. Regarding the isolation of the cyanobacterial exoproteome, the technique is based on the concentration of the cell-free medium after removal of the major contaminants by centrifugation and filtration. This strategy allows for reliable isolation of proteins that reach the extracellular milieu via membrane transporters or outer membrane vesicles. These proteins can be subsequently identified using standard mass spectrometry techniques. The protocols presented here can be applied not only to a wide range of cyanobacteria, but also to other bacterial strains. Furthermore, these procedures can be easily tailored according to the final use of the products, purity degree required, and bacterial strain.

A schematic representation of the method described to extract released carbohydrate polymers from cyanobacterial cultures is depicted in Figure 1. Precipitated polymers from the moderate EPS producer cyanobacterium Synechocystis sp. PCC 6803 and the efficient EPS producer Cyanothece sp. CCY 0110 are shown in Figure 2. In Figure 3, lyophilized polymers with different degrees of contamination are shown, highlighting ...

Watch this Scientific Journal Video about Looking Outwards: Isolation of Cyanobacterial Released Carbohydrate Polymers and Proteins at JoVE.com

Looking Outwards: Isolation of Cyanobacterial Released Carbohydrate Polymers and Proteins

Here, protocols for the isolation of cyanobacterial released carbohydrate polymers and isolation of their exoproteomes are described. Both procedures embody key steps to obtain polymers or proteins with high purity degrees that can be used for further analysis or applications. They can also be easily adapted according to specific user needs.

Cyanobacteria can actively secrete a wide range of biomolecules into the extracellular environment, such as heteropolysaccharides and proteins. The ...

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6.5K Views.  Universidade do Porto. Deze protocollen die we ontwikkelden zijn belangrijk om de afscheidingsmechanismen in cyanobacteriën en hun vrijgekomen producten te bestuderen, namelijk de extracellulaire koolhydraatpolymeren en eiwitten. De geproduceerde kennis stelt ons in staat om deze producten aan te passen voor verschillende toepassingen, namelijk biotechnologische en biomedische toepassingen. Deze protocollen zijn zeer eenvoudig.Ze kunnen worden afgestemd op het producerende organisme, de behoeften van de geb...

Video: Looking Outwards: Isolation of Cyanobacterial Released Carbohydrate Polymers and Proteins

Determination of the Glycogen Content in Cyanobacteria

Cyanobacteria accumulate glycogen as a major intracellular carbon and energy storage&#160;during photosynthesis. Recent developments in research have highlighted complex mechanisms of glycogen metabolism, including the diel cycle of biosynthesis and catabolism, redox regulation, and the involvement of non-coding RNA. At the same time, efforts are being made to redirect carbon from glycogen to desirable products in genetically engineered cyanobacteria to enhance product yields. Several methods are used to determine the glycogen contents in cyanobacteria, with variable accuracies and technical complexities. Here, we provide a detailed protocol for the reliable determination of the glycogen content in cyanobacteria that can be performed in a standard life science laboratory. The protocol entails the selective precipitation of glycogen from the cell lysate and the enzymatic depolymerization of glycogen to generate glucose monomers, which are detected by a glucose oxidase-peroxidase (GOD-POD) enzyme coupled assay. The method has been applied to Synechocystis sp. PCC 6803 and Synechococcus sp. PCC 7002, two model cyanobacterial species that are widely used in metabolic engineering. Moreover, the method successfully showed differences in the glycogen contents between the wildtype and mutants defective in regulatory elements or glycogen biosynthetic genes.

Here, we present a reliable and easy assay to measure the glycogen content in cyanobacterial cells. The procedure entails precipitation, selectable depolymerization, and the detection of glucose residues. This method is suitable for both wildtype and genetically engineered strains and can facilitate the metabolic engineering of cyanobacteria.

Cyanobacteria accumulate glycogen as a major intracellular carbon and energy storage&#160;during photosynthesis. Recent developments in research have ...

Au-Interaction of Slp1 Polymers and Monolayer from Lysinibacillus sphaericus JG-B53 - QCM-D, ICP-MS and AFM as Tools for Biomolecule-metal Studies

In this publication the gold sorption behavior of surface layer (S-layer) proteins (Slp1) of Lysinibacillus sphaericus JG-B53 is described. These biomolecules arrange in paracrystalline two-dimensional arrays on surfaces, bind metals, and are thus interesting for several biotechnical applications, such as biosorptive materials for the removal or recovery of different elements from the environment and industrial processes. The deposition of Au(0) nanoparticles on S-layers, either by S-layer directed synthesis 1 or adsorption of nanoparticles, opens new possibilities for diverse sensory applications. Although numerous studies have described the biosorptive properties of S-layers 2-5, a deeper understanding of protein-protein and protein-metal interaction still remains challenging. In the following study, inductively coupled mass spectrometry (ICP-MS) was used for the detection of metal sorption by suspended S-layers. This was correlated to measurements of quartz crystal microbalance with dissipation monitoring (QCM-D), which allows the online detection of proteinaceous monolayer formation and metal deposition, and thus, a more detailed understanding on metal binding.
The ICP-MS results indicated that the binding of Au(III) to the suspended S-layer polymers is pH dependent. The maximum binding of Au(III) was obtained at pH 4.0. The QCM-D investigations enabled the detection of Au(III) sorption as well as the deposition of Au(0)-NPs in real-time during the in situ experiments. Further, this method allowed studying the influence of metal binding on the protein lattice stability of Slp1. Structural properties and protein layer stability could be visualized directly after QCM-D experiment using atomic force microscopy (AFM). In conclusion, the combination of these different methods provides a deeper understanding of metal binding by bacterial S-layer proteins in suspension or as monolayers on either bacterial cells or recrystallized surfaces.

Au-Interaction of Slp1 Polymers and Monolayer from Lysinibacillus sphaericus JG-B53 - QCM-D, ICP-MS and AFM as Tools for Biomolecule-metal Studies

To obtain basic information on the sorption and recycling of gold from aqueous systems the interaction of Au(III) and Au(0) nanoparticles on S-layer proteins were investigated. The sorption of protein polymers was investigated by ICP-MS and that of proteinaceous monolayers by QCM-D. Subsequent AFM enables the imaging of the nanostructures.

In this publication the gold sorption behavior of surface layer (S-layer) proteins (Slp1) of Lysinibacillus sphaericus JG-B53 is described. These ...

Chemistry

Spectrophotometric Determination of Phycobiliprotein Content in Cyanobacterium Synechocystis

This is a simple protocol for the quantitative determination of phycobiliprotein content in the model cyanobacterium Synechocystis. Phycobiliproteins are the most important components of phycobilisomes, the major light-harvesting antennae in cyanobacteria and several algae taxa. The phycobilisomes of Synechocystis contain two phycobiliproteins: phycocyanin and allophycocyanin. This protocol describes a simple, efficient, and reliable method for the quantitative determination of both phycocyanin and allophycocyanin in this model cyanobacterium. We compared several methods of phycobiliprotein extraction and spectrophotometric quantification. The extraction procedure as described in this protocol was also successfully applied to other cyanobacteria strains such as Cyanothece sp., Synechococcuselongatus, Spirulina sp., Arthrospira sp., and Nostoc sp., as well as to red algae Porphyridium cruentum. However, the extinction coefficients of specific phycobiliproteins from various taxa can differ and it is, therefore, recommended to validate the spectrophotometric quantification method for every single strain individually. The protocol requires little time and can be performed in any standard life science laboratory since it requires only standard equipment.

Spectrophotometric Determination of Phycobiliprotein Content in Cyanobacterium Synechocystis

Here, we present a protocol to quantitatively determine phycobiliprotein content in the cyanobacterium Synechocystis using a spectrophotometric method. The extraction procedure was also successfully applied to other cyanobacteria and algae strains; however, due to variations in pigment absorption spectra, it is necessary to test the spectrophotometric equations for each strain individually.

This is a simple protocol for the quantitative determination of phycobiliprotein content in the model cyanobacterium Synechocystis. Phycobiliproteins are ...

Isolation, Propagation, and Identification of Bacterial Species with Hydrocarbon Metabolizing Properties from Aquatic Habitats

Hydrocarbon pollutants are recalcitrant to degradation and their accumulation in the environment is toxic to all life forms. Bacteria encode numerous catalytic enzymes and are naturally capable of metabolizing hydrocarbons. Scientists harness biodiversity in aquatic ecosystems to isolate bacteria with biodegradation and bioremediation potential. Such isolates from the environment provide a rich set of metabolic pathways and enzymes, which can be further utilized to scale up the degradation process at an industrial scale. In this article, we outline the general process of isolation, propagation, and identification of bacterial species from aquatic habitats and screen their ability to utilize hydrocarbons as the sole carbon source in vitro using simple techniques. The present protocol describes the isolation of various bacterial species and their subsequent identification using the 16S rRNA analysis. The protocol also presents steps for characterizing the hydrocarbon degrading potential of bacterial isolates. This protocol will be useful for researchers trying to isolate bacterial species from environmental habitats for their biotechnological applications.

We present the process of isolating, propagating, and characterizing hydrocarbon-degrading bacteria from aquatic habitats. The protocol outlines bacterial isolation, identification by the 16S rRNA method, and testing of their hydrocarbon-degrading potential. This article would help researchers in characterizing microbial biodiversity in environmental samples, and specifically screen for microbes with bioremediation potential.

Hydrocarbon pollutants are recalcitrant to degradation and their accumulation in the environment is toxic to all life forms. Bacteria encode numerous ...

Environment

Extraction of Non-Protein Amino Acids from Cyanobacteria for Liquid Chromatography-Tandem Mass Spectrometry Analysis

Non-protein amino acids (NPAAs) are a large class of amino acids (AAs) that are not genetically encoded for translation into proteins. The analysis of NPAAs can provide crucial information about cellular uptake and/or function, metabolic pathways, and potential toxicity. &#946;-methylamino-L-alanine (BMAA) is a neurotoxic NPAA produced by various algae species and is associated with an increased risk for neurodegenerative diseases, which has led to significant research interest. There are numerous ways to extract AAs for analysis, with liquid chromatography-tandem mass spectrometry being the most common, requiring protein precipitation followed by acid hydrolysis of the protein pellet. Studies on the presence of BMAA in algal species provide contradictory results, with the use of unvalidated sample preparation/extraction and analysis a primary cause. Like most NPAAs, protein precipitation in 10% aqueous TCA and hydrolysis with fuming HCl is the most appropriate form of extraction for BMAA and its isomers aminoethylglycine (AEG) and 2,4-diaminobutyric acid (2,4-DAB). The present protocol describes the steps in a validated NPAA extraction method commonly used in research and teaching laboratories.

The present protocol describes the extraction of non-protein amino acids from biological matrices via trichloroacetic acid (TCA) protein precipitation and acid hydrolysis before analysis using liquid chromatography-tandem mass spectrometry.

Non-protein amino acids (NPAAs) are a large class of amino acids (AAs) that are not genetically encoded for translation into proteins. The analysis of ...

Isolation of mRNAs Associated with Yeast Mitochondria to Study Mechanisms of Localized Translation

Most of mitochondrial proteins are encoded in the nucleus and need to be imported into the organelle. Import may occur while the protein is synthesized near the mitochondria. Support for this possibility is derived from recent studies, in which many mRNAs encoding mitochondrial proteins were shown to be localized to the mitochondria vicinity. Together with earlier demonstrations of ribosomes&#8217; association with the outer membrane, these results suggest a localized translation process. Such localized translation may improve import efficiency, provide unique regulation sites and minimize cases of ectopic expression. Diverse methods have been used to characterize the factors and elements that mediate localized translation. Standard among these is subcellular fractionation by differential centrifugation. This protocol has the advantage of isolation of mRNAs, ribosomes and proteins in a single procedure. These can then be characterized by various molecular and biochemical methods. Furthermore, transcriptomics and proteomics methods can be applied to the resulting material, thereby allow genome-wide insights. The utilization of yeast as a model organism for such studies has the advantages of speed, costs and simplicity. Furthermore, the advanced genetic tools and available deletion strains facilitate verification of candidate factors.

Many mRNAs encoding mitochondrial proteins are associated with the mitochondria outer membrane. We describe a subcellular fractionation procedure aimed at isolation of yeast mitochondria with its associated mRNAs and ribosomes. This protocol can be applied to cells grown under diverse conditions&#160;in order to reveal mechanisms of mRNA localization and localized translation near the mitochondria.

Most of mitochondrial proteins are encoded in the nucleus and need to be imported into the organelle. Import may occur while the protein is synthesized ...

Biology

Protocol for Co-Culturing Sucrose-Secreting Cyanobacteria with Fungal Partners

Assembly and Quantification of Co-Cultures Combining Heterotrophic Yeast with Phototrophic Sugar-Secreting Cyanobacteria

With the increasing demand for sustainable biotechnologies, mixed consortia containing a phototrophic microbe and heterotrophic partner species are being explored as a method for solar-driven bioproduction. One approach involves the use of CO2-fixing cyanobacteria that secrete organic carbon to support the metabolism of a co-cultivated heterotroph, which in turn transforms the carbon into higher-value goods or services. In this protocol, a technical description to assist the experimentalist in the establishment of a co-culture combining a sucrose-secreting cyanobacterial strain with a fungal partner(s), as represented by model yeast species, is provided. The protocol describes the key prerequisites for co-culture establishment: Defining the media composition, monitoring the growth characteristics of individual partners, and the analysis of mixed cultures with multiple species combined in the same growth vessel. Basic laboratory techniques for co-culture monitoring, including microscopy, cell counter, and single-cell flow cytometry, are summarized, and examples of nonproprietary software to use for data analysis of raw flow cytometry standard (FCS) files in line with FAIR (Findable, Accessible, Interoperable, Reusable) principles are provided. Finally, commentary on the bottlenecks and pitfalls frequently encountered when attempting to establish a co-culture with sugar-secreting cyanobacteria and a novel heterotrophic partner is included. This protocol provides a resource for researchers attempting to establish a new pair of co-cultured microbes that includes a cyanobacterium and a heterotrophic microbe.

This protocol provides a comprehensive guideline for the setup and quantitative monitoring of co-cultures, including photoautotrophic sugar-secreting cyanobacteria and heterotrophic yeasts.

With the increasing demand for sustainable biotechnologies, mixed consortia containing a phototrophic microbe and heterotrophic partner species are being ...

Bioengineering

Automated Modular High Throughput Exopolysaccharide Screening Platform Coupled with Highly Sensitive Carbohydrate Fingerprint Analysis

Many microorganisms are capable of producing and secreting exopolysaccharides (EPS), which have important implications in medical fields, food applications or in the replacement of petro-based chemicals. We describe an analytical platform to be automated on a liquid handling system that allows the fast and reliable analysis of the type and the amount of EPS produced by microorganisms. It enables the user to identify novel natural microbial exopolysaccharide producers and to analyze the carbohydrate fingerprint of the corresponding polymers within one day in high-throughput (HT). Using this platform, strain collections as well as libraries of strain variants that might be obtained in engineering approaches can be screened. The platform has a modular setup, which allows a separation of the protocol into two major parts. First, there is an automated screening system, which combines different polysaccharide detection modules: a semi-quantitative analysis of viscosity formation via a centrifugation step, an analysis of polymer formation via alcohol precipitation and the determination of the total carbohydrate content via a phenol-sulfuric-acid transformation. Here, it is possible to screen up to 384 strains per run. The second part provides a detailed monosaccharide analysis for all the selected EPS producers identified in the first part by combining two essential modules: the analysis of the complete monomer composition via ultra-high performance liquid chromatography coupled with ultra violet and electrospray ionization ion trap detection (UHPLC-UV-ESI-MS) and the determination of pyruvate as a polymer substituent (presence of pyruvate ketal) via enzymatic oxidation that is coupled to a color formation. All the analytical modules of this screening platform can be combined in different ways and adjusted to individual requirements. Additionally, they can all be handled manually or performed with a liquid handling system. Thereby, the screening platform enables a huge flexibility in order to identify various EPS.

We present an automated modular high-throughput-method for the identification and characterization of microbial exopolysaccharides in small scale. This method combines a fast preselection to analyze the total amount of secreted polysaccharides with a detailed carbohydrate fingerprint to enable the fast screening of newly isolated bacterial strains or entire strain collections.

Many microorganisms are capable of producing and secreting exopolysaccharides (EPS), which have important implications in medical fields, food ...

Isolation and Characterization of Intact Phycobilisome in Cyanobacteria

In cyanobacteria, phycobilisome is a vital antenna protein complex that harvests light and transfers energy to photosystem I and II for photochemistry. Studying the structure and composition of phycobilisome is of great interest to scientists because it reveals the evolution and divergence of photosynthesis in cyanobacteria. This protocol provides a detailed and optimized method to break cyanobacterial cells at low cost by a bead-beater efficiently. The intact phycobilisome can then be isolated from the cell extract by sucrose gradient ultracentrifugation. This method has demonstrated being suitable for both model and non-model cyanobacteria with different cell types. A step-by-step procedure is also provided to confirm the integrity and property of phycobiliproteins by 77K fluorescence spectroscopy and SDS-PAGE stained by zinc sulfate and Coomassie Blue. The isolated phycobilisome can also be subjected to further structural and compositional analyses. Overall, this protocol provides a helpful starting guide that allows researchers unfamiliar with cyanobacteria to quickly isolate and characterize intact phycobilisome.

The current protocol details the isolation of phycobilisomes from cyanobacteria by centrifugation through a discontinuous sucrose density gradient. The fractions of intact phycobilisomes are confirmed by 77K fluorescent emission spectrum and SDS-PAGE analysis. The resulting phycobilisome fractions are suitable for negative staining of TEM and mass spectrometry analysis.

In cyanobacteria, phycobilisome is a vital antenna protein complex that harvests light and transfers energy to photosystem I and II for photochemistry. ...

Isolation and Characterization of Cyanobacterial Extracellular Vesicles

Cyanobacteria are a diverse group of photosynthetic, Gram-negative bacteria that play critical roles in global ecosystems and serve as essential biotechnology models. Recent work has demonstrated that both marine and freshwater cyanobacteria produce extracellular vesicles -&#160;small membrane-bound structures released from the outer surface of the microbes. While vesicles likely contribute to diverse biological processes, their specific functional roles in cyanobacterial biology remain largely unknown. To encourage and advance research in this area, a detailed protocol is presented for isolating, concentrating, and purifying cyanobacterial extracellular vesicles. The current work discusses methodologies that have successfully isolated vesicles from large cultures of Prochlorococcus, Synechococcus, and Synechocystis. Methods for quantifying and characterizing vesicle samples from these strains are presented. Approaches for isolating vesicles from aquatic field samples are also described. Finally, typical challenges encountered with cyanobacterial vesicle purification, methodological considerations for different downstream applications, and the trade-offs between approaches are also discussed.

The present protocol providesdetailed descriptions for isolation, concentration,and characterization of extracellular vesicles from cyanobacterial cultures. Approaches for purifying vesicles from cultures at different scales, trade-offs among methodologies, and considerations for working with field samples are also discussed.

Looking Outwards: Isolation of Cyanobacterial Released Carbohydrate Polymers and Proteins

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