This work is supported by the National Natural Science Foundation of China (82060341,81560304) and by the Academician Innovation Platform Scientific Research Project of Hainan Province (YSPTZX202134).

This study was approved by the Ethics Committee of Hainan Medical University. The tissue samples used in this study are not considered to be studies involving human subjects. These specimens were obtained for the purpose of forensic pathological diagnosis, and the rest were used for the extraction of diatom DNA in this experiment. Researchers cannot readily identify individuals to obtain informed consent from relevant stakeholders.
NOTE: To ensure the general applicability of the research meth...

Economical Diatom DNA Extraction Using a Modified Kit

<ol>
	<li>Liu, C., Cong, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Review+and+prospect+of+diagnosis+of+drowning+deaths+in+water.">Review and prospect of diagnosis of drowning deaths in water.</a> Fa Yi Xue Za Zhi. 38 (1), 3-13 (2022).</li><li>Frisoni, 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=Forensic+diagnosis+of+freshwater+or+saltwater+drowning+using+the+marker+aquaporin+5:+An+immunohistochemical+study.">Forensic diagnosis of freshwater or saltwater drowning using the marker aquaporin 5: An immunohistochemical study.</a> Medicina (Kaunas). 58 (10), 1458 (2022).</li><li>Mann, D. G., Vanormelingen, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+inordinate+fondness?+The+number,+distributions,+and+origins+of+diatom+species.">An inordinate fondness? The number, distributions, and origins of diatom species.</a> J Eukaryot Microbiol. 60 (4), 414-420 (2013).</li><li>Pfister, L., 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=Terrestrial+diatoms+as+tracers+in+catchment+hydrology:+a+review.">Terrestrial diatoms as tracers in catchment hydrology: a review.</a> WIREs Water. 4, 1241 (2017).</li><li>Yu, W., 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=An+improved+automated+diatom+detection+method+based+on+YOLOv5+framework+and+its+preliminary+study+for+taxonomy+recognition+in+the+forensic+diatom+test.">An improved automated diatom detection method based on YOLOv5 framework and its preliminary study for taxonomy recognition in the forensic diatom test.</a> Front Microbiol. 13, 963059 (2022).</li><li>Zhang, 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+length+and+width+of+diatoms+in+drowning+cases+as+the+evidence+of+diatoms+penetrating+the+alveoli-capillary+barrier.">The length and width of diatoms in drowning cases as the evidence of diatoms penetrating the alveoli-capillary barrier.</a> Int J Legal Med. 134 (3), 1037-1042 (2020).</li><li>Kihara, Y., 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=Experimental+water+injection+into+lungs+using+an+animal+model:+Verification+of+the+diatom+concentration+test+to+diagnose+drowning.">Experimental water injection into lungs using an animal model: Verification of the diatom concentration test to diagnose drowning.</a> Forensic Sci Int. 327, 110983 (2021).</li><li>Shen, X., 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+false-positive+results+of+diatom+test+in+the+diagnosis+of+drowning-would+not+be+an+impediment.">Analysis of false-positive results of diatom test in the diagnosis of drowning-would not be an impediment.</a> Int J Legal Med. 133 (6), 1819-1824 (2019).</li><li>Manoylov, K. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Taxonomic+identification+of+algae+(morphological+and+molecular):+species+concepts,+methodologies,+and+their+implications+for+ecological+bioassessment.">Taxonomic identification of algae (morphological and molecular): species concepts, methodologies, and their implications for ecological bioassessment.</a> J Phycol. 50 (3), 409-424 (2014).</li><li>Uchiyama, T., 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=A+new+molecular+approach+to+help+conclude+drowning+as+a+cause+of+death:+simultaneous+detection+of+eight+bacterioplankton+species+using+real-time+PCR+assays+with+TaqMan+probes.">A new molecular approach to help conclude drowning as a cause of death: simultaneous detection of eight bacterioplankton species using real-time PCR assays with TaqMan probes.</a> Forensic Sci Int. 222 (1-3), 11-26 (2012).</li><li>Kakizaki, 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=Detection+of+diverse+aquatic+microbes+in+blood+and+organs+of+drowning+victims:+first+metagenomic+approach+using+high-throughput+454-pyrosequencing.">Detection of diverse aquatic microbes in blood and organs of drowning victims: first metagenomic approach using high-throughput 454-pyrosequencing.</a> Forensic Sci Int. 220 (1-3), 135-146 (2012).</li><li>Cai, J., Wang, B., Chen, J. H., Deng, J. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+Progress+of+High-Throughput+Sequencing+Technology+in+Forensic+Diatom+Detection.">Application Progress of High-Throughput Sequencing Technology in Forensic Diatom Detection.</a> Fa Yi Xue Za Zhi. 38 (1), 20-30 (2022).</li><li>Xiao, 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=Development+and+application+of+a+multiplex+PCR+system+for+drowning+diagnosis.">Development and application of a multiplex PCR system for drowning diagnosis.</a> Electrophoresis. 42 (11), 1270-1278 (2021).</li><li>Yarimizu, K., 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=Development+of+an+absolute+quantification+method+for+ribosomal+RNA+gene+copy+numbers+per+eukaryotic+single+cell+by+digital+PCR.">Development of an absolute quantification method for ribosomal RNA gene copy numbers per eukaryotic single cell by digital PCR.</a> Harmful Algae. 103, 102008 (2021).</li><li>Dalgic, A. D., Atila, D., Karatas, A., Tezcaner, A., Keskin, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diatom+shell+incorporated+PHBV/PCL-pullulan+co-electrospun+scaffold+for+bone+tissue+engineering.">Diatom shell incorporated PHBV/PCL-pullulan co-electrospun scaffold for bone tissue engineering.</a> Mater Sci Eng C Mater Biol Appl. 100, 735-746 (2019).</li><li>Malviya, S., 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=Insights+into+global+diatom+distribution+and+diversity+in+the+world's+ocean.">Insights into global diatom distribution and diversity in the world's ocean.</a> Proc Natl Acad Sci U S A. 113 (11), 1516-1525 (2016).</li><li>Brunner, 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=Analytical+studies+of+silica+biomineralization:+towards+an+understanding+of+silica+processing+by+diatoms.">Analytical studies of silica biomineralization: towards an understanding of silica processing by diatoms.</a> Appl Microbiol Biotechnol. 84 (4), 607-616 (2009).</li><li>Annunziata, 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=An+optimised+method+for+intact+nuclei+isolation+from+diatoms.">An optimised method for intact nuclei isolation from diatoms.</a> Sci Rep. 11 (1), 1681 (2021).</li><li>Zhao, 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=The+diagnostic+value+of+quantitative+assessment+of+diatom+test+for+drowning:+An+analysis+of+128+water-related+death+cases+using+microwave+digestion-vacuum+filtration-automated+scanning+electron+microscopy.">The diagnostic value of quantitative assessment of diatom test for drowning: An analysis of 128 water-related death cases using microwave digestion-vacuum filtration-automated scanning electron microscopy.</a> J Forensic Sci. 62 (6), 1638-1642 (2017).</li><li>Zhao, J., Liu, C., Hu, S., He, S., Lu, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microwave+digestion-vacuum+filtration-automated+scanning+electron+microscopy+as+a+sensitive+method+for+forensic+diatom+test.">Microwave digestion-vacuum filtration-automated scanning electron microscopy as a sensitive method for forensic diatom test.</a> Int J Legal Med. 127 (2), 459-463 (2013).</li><li>Cai, 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=Improved+glass+bead-vortex+oscillation+method+for+DNA+extraction+from+diatom.">Improved glass bead-vortex oscillation method for DNA extraction from diatom.</a> Fa Yi Xue Za Zhi. 38 (1), 119-126 (2022).</li><li>Zimmermann, J., Jahn, R., Gemeinholzer, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Barcoding+diatoms:+evaluation+of+the+V4+subregion+on+the+18S+rRNA+gene,+including+new+primers+and+protocols.">Barcoding diatoms: evaluation of the V4 subregion on the 18S rRNA gene, including new primers and protocols.</a> Org Divers Evol. 11 (3), 173-192 (2011).</li><li>Vinayak, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chloroplast+gene+markers+detect+diatom+DNA+in+a+drowned+mice+establishing+drowning+as+a+cause+of+death.">Chloroplast gene markers detect diatom DNA in a drowned mice establishing drowning as a cause of death.</a> Electrophoresis. , (2020).</li><li>Plante, C. J., Hill-Spanik, K., Cook, M., Graham, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Environmental+and+Spatial+Influences+on+Biogeography+and+Community+Structure+of+Saltmarsh+Benthic+Diatoms.">Environmental and Spatial Influences on Biogeography and Community Structure of Saltmarsh Benthic Diatoms.</a> Estuaries and Coasts. 44, 147-161 (2021).</li><li>Heid, C. A., Stevens, J., Livak, K. J., Williams, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Real+time+quantitative+PCR.">Real time quantitative PCR.</a> Genome Res. 6 (10), 986-994 (1996).</li><li>Ben Amor, F., 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=Development+of+a+novel+TaqMan+qPCR+assay+for+rapid+detection+and+quantification+of+Gymnodinium+catenatum+for+application+to+harmful+algal+bloom+monitoring+in+coastal+areas+of+Tunisia.">Development of a novel TaqMan qPCR assay for rapid detection and quantification of Gymnodinium catenatum for application to harmful algal bloom monitoring in coastal areas of Tunisia.</a> Environ Sci Pollut Res Int. 29 (42), 63953-63963 (2022).</li><li>Doddaraju, 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=Reliable+and+early+diagnosis+of+bacterial+blight+in+pomegranate+caused+by+Xanthomonas+axonopodis+pv.+punicae+using+sensitive+PCR+techniques.">Reliable and early diagnosis of bacterial blight in pomegranate caused by Xanthomonas axonopodis pv. punicae using sensitive PCR techniques.</a> Sci Rep. 9 (1), 10097 (2019).</li><li>Lunetta, P., Miettinen, A., Spilling, K., Sajantila, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=False-positive+diatom+test:+a+real+challenge?+A+post-mortem+study+using+standardized+protocols.">False-positive diatom test: a real challenge? A post-mortem study using standardized protocols.</a> Leg Med (Tokyo). 15 (5), 229-234 (2013).</li><li>Marquesda Silva, J., Cruz, S., Cartaxana, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inorganic+carbon+availability+in+benthic+diatom+communities:+photosynthesis+and+migration.">Inorganic carbon availability in benthic diatom communities: photosynthesis and migration.</a> Philos Trans R Soc Lond B Biol Sci. 372 (1728), 20160398 (2017).</li><li>Yu, Z., 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+effect+of+enzyme+digestion+time+on+the+detection+of+diatom+species.">The effect of enzyme digestion time on the detection of diatom species.</a> Pak J Pharm Sci. 27 (3 Suppl), 691-694 (2014).</li><li>Liu, M., 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=Diatom+DNA+barcodes+for+forensic+discrimination+of+drowning+incidents.">Diatom DNA barcodes for forensic discrimination of drowning incidents.</a> FEMS Microbiol Lett. 367 (17), 145 (2020).</li><li>Mizushima, W., 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+novel+heart-specific+RING+finger+protein+207+is+involved+in+energy+metabolism+in+cardiomyocytes.">The novel heart-specific RING finger protein 207 is involved in energy metabolism in cardiomyocytes.</a> J Mol Cell Cardiol. 100, 43-53 (2016).</li><li>Zimmermann, 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=Taxonomic+reference+libraries+for+environmental+barcoding:+a+best+practice+example+from+diatom+research.">Taxonomic reference libraries for environmental barcoding: a best practice example from diatom research.</a> PLoS One. 9 (9), 108793 (2014).</li></ol>

Diatom cells are protected by hard siliceous cell walls17, and this structure must be destroyed to extract diatom DNA. Ordinary kits do not easily destroy the siliceous shell of diatoms; thus it is difficult to successfully extract diatom DNA21. Our laboratory improved the most commonly used blood DNA extraction kit, adding glass beads of different diameters and different mass ratio in the process of diatom extraction. Vortex oscillation is carried out at the same time, whi...

In forensic practice, determining whether a corpse found in the water drowning or was thrown into the water after death is essential for the proper resolution of the case1. It is also one of the difficult issues that need to be solved urgently in forensic practice2. Diatoms are abundant in the natural environment (especially in water)3,4. In the process of drowning, due to hypoxia and stress response, people will have intense breathing movements and inhale a large amount of drowning liquid. Therefore, the diatoms in the water enter the lung with the drowning liquid, and some diatoms can enter the blood circulation through the alveolar-capillary barrier and spread to internal organs with the blood flow5,6. The detection of diatoms in internal tissues and organs such as lung, liver, and bone marrow is a strong evidence of drowning before death7,8. Currently, forensic diatom testing is mainly based on morphological testing methods. After a series of pre-digestion of the tissue, the morphological qualitative and quantitative estimations of undigested diatoms are carried out under the microscope. During this period, dangerous and environmentally unfriendly reagents such as nitric acid need to be used. This process is time-consuming and requires researchers to have solid taxonomic expertise and extensive experience. These all bring certain challenges to the forensic staff9. Diatom DNA testing technology is a new technology for diatom testing developed in recent years10,11,12. This technology realizes the species identification of diatoms by analyzing the specific DNA sequence composition of diatoms13,14. PCR technology and sequencing technology are commonly used technical methods, but their basis is the successful extraction of DNA from diatoms. However, diatoms have a special structure different from other organisms, making their DNA extraction techniques also different.
The cell wall of diatom has a high degree of silicification, and its main component is silicon dioxide15,16,17. The siliceous cell wall is very hard, and it must be destroyed before extract the DNA. Ordinary DNA extraction kits are often difficult to use directly for the extraction of diatom DNA because they cannot destroy the siliceous shell of diatoms18. Therefore, destroying the siliceous shell of diatoms is one of the key technical problems to be solved in extracting diatom DNA.
At the same time, since the number of diatoms contained in forensic research samples, whether water samples or organs and tissues of drowned bodies, is often limited, it is necessary to enrich diatoms. The essence of enrichment is the separation of substances. While trying to gather diatoms together, minimize the content of other material components (interfering components). In forensic work, laboratories often use centrifugation or membrane filtration enrichment methods to separate diatom cells19. However, since vacuum pumping equipment is not widely used, the membrane enrichment method is not often used in ordinary primary forensic laboratories. So, the centrifugation method is still commonly diatom enrichment in forensic laboratories20.
DNA extraction from diatoms is currently used primarily in forensic practice, and there are significant limitations to its application. At present, there are few diatom DNA extraction kits used in forensic science on the market and they are generally expensive21. This article provides an improved diatom DNA extraction method, making diatom DNA extraction simple, convenient and cost effective. This increases the application of subsequent molecular biology testing of diatoms and can better solve problems related to drowning in forensic medicine through diatom testing. This method breaks the siliceous cell walls of diatoms by adding glass beads and setting an appropriate time for vortex. In this way, the proteinase K and the binding solution rapidly lyse the cells and inactivate various enzymes in the cells. The genomic DNA is absorbed in the matrix membrane in the adsorption column and finally eluted by the elution buffer. Such an improved whole blood gene extraction kit improves the diatom DNA extraction effect of the blood kit in forensic examination materials, reduces the cost of diatom DNA extraction in forensic practice, and can be better applied to grassroot forensic research.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Binding Buffer</td>
			<td>BioTeke</td>
			<td>B010006022</td>
			<td>rapidly lysing cells</td>
		</tr>
		<tr>
			<td>ChemoHS qPCR Mix</td>
			<td>Monad</td>
			<td>00007547-120506</td>
			<td>qPCR Mix</td>
		</tr>
		<tr>
			<td>D2000 DNA ladder</td>
			<td>Real-Times(Beijing) Biotechnology</td>
			<td>RTM415</td>
			<td>Measure the position of electrophoretic bands</td>
		</tr>
		<tr>
			<td>D512</td>
			<td>Taihe Biotechnology</td>
			<td>TW21109196</td>
			<td>forword primer</td>
		</tr>
		<tr>
			<td>D978</td>
			<td>Taihe Biotechnology</td>
			<td>TW21109197</td>
			<td>reverse primer</td>
		</tr>
		<tr>
			<td>Elution buffer</td>
			<td>BioTeke</td>
			<td>B010006022</td>
			<td>A low-salt elution buffer washes off the DNA</td>
		</tr>
		<tr>
			<td>Glass bead</td>
			<td>Yingxu Chemical Machinery(Shanghai)&#160;</td>
			<td>70181000</td>
			<td>Special glass beads for dispersing and grinding</td>
		</tr>
		<tr>
			<td>Import adsorption column</td>
			<td>BioTeke</td>
			<td>B2008006022</td>
			<td>Adsorption column with silica matrix membrane</td>
		</tr>
		<tr>
			<td>Inhibitor Removal Buffer</td>
			<td>BioTeke</td>
			<td>B010006022</td>
			<td>Removal of Inhibitors in DNA Extraction</td>
		</tr>
		<tr>
			<td>Isopropanol</td>
			<td>BioTeke</td>
			<td>B010006022</td>
			<td>Precipitate or isolate DNA</td>
		</tr>
		<tr>
			<td>MIX-30S Mini Mixer</td>
			<td>Miulab</td>
			<td>MUC881206</td>
			<td>oscillatory action</td>
		</tr>
		<tr>
			<td>Proteinase K</td>
			<td>BioTeke</td>
			<td>B010006022</td>
			<td>Inactivation of intracellular nucleases and other proteins</td>
		</tr>
		<tr>
			<td>Rotor-Gene Q 5plex HRM</td>
			<td>Qiagen</td>
			<td>R1116175</td>
			<td>real-time fluorescence quantification PCR</td>
		</tr>
		<tr>
			<td>Speed Micro-Centrifuge</td>
			<td>Scilogex</td>
			<td>9013001121</td>
			<td>centrifuge</td>
		</tr>
		<tr>
			<td>Tanon 3500R Gel Imager</td>
			<td>Tanon</td>
			<td>16T5553R-455</td>
			<td>gel imaging</td>
		</tr>
		<tr>
			<td>Taq Mix Pro</td>
			<td>Monad</td>
			<td>00007808-140534</td>
			<td>PCR Mix</td>
		</tr>
		<tr>
			<td>Thermo Cycler</td>
			<td>Zhuhai Hema</td>
			<td>VRB020A</td>
			<td>ordinary PCR</td>
		</tr>
		<tr>
			<td>Wash Buffer</td>
			<td>BioTeke</td>
			<td>B010006022</td>
			<td>Remove impurities such as cell metabolites</td>
		</tr>
	</tbody>
</table>

extraction of diatom dna from water samples and tissues

Diatom testing is an essential auxiliary means in forensic practice to determine whether the corpse drowned in water and to infer the drowning location. Diatom testing is also an important research content in the field of the environment and plankton. The diatom molecular biology testing technology, which focuses on diatom DNA as the primary research object, is a new method of diatom testing. Diatom DNA extraction is the basis of diatom molecular testing. At present, the kits commonly used for diatom DNA extraction are expensive, which increases the cost of carrying out related research. Our laboratory improved the general whole blood genomic DNA rapid extraction kit and obtained a satisfactory diatom DNA extraction effect, thus providing an alternative economical and affordable DNA extraction solution based on glass beads for related research. The diatom DNA extracted using this protocol could satisfy many downstream applications, such as PCR and sequencing.

Author Spotlight: Diatom Testing for Forensic Drowning Examination 

Extraction of Diatom DNA from Water Samples and Tissues

Our research mainly focus on the topic of drowning. We wanted to answer the question of whether the body found in the water died from drowning, as well to answer another question of where the person fell into the water. That means to know the location of the drowning.Compared with other technologies, we provide a simple, convenient, and economical diatom DNA extraction protocol that we can use better in forensic research, especially in basic forensic practice. Our laboratory will further focus on the drowning related problems based on the pattern in the water, such as reason of death, post mortem interval and so on. What's more, we also carry on the research through the forensic entomology and a some special phenomenons in the tropical forensic medicines.

Since the DNA solution extracted by the currently used DNA extraction method contains all DNA components from different sources in the sample, the DNA obtained by this protocol was no exception. So, the DNA solution was not just a solution of diatom genomic DNA. The primers that can specifically amplify diatom 18S rDNA fragments were selected by consulting the literature22,23,24. The primers were verified by NCBI-Blast Primer, a...

Watch this Scientific Journal Video about Diatom Testing for Forensic Drowning Examination at JoVE.com

This article describes a protocol for diatom DNA extraction using a modified common DNA extraction kit.

Diatom testing is an essential auxiliary means in forensic practice to determine whether the corpse drowned in water and to infer the drowning location. ...

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1.2K visualizações.  Hainan Medical University, Hainan Provincial Academician Workstation (tropical forensic medicine). Nossa pesquisa se concentra principalmente no tema do afogamento. Queríamos responder à pergunta se o corpo encontrado na água morreu por afogamento, bem como responder a outra pergunta de onde a pessoa caiu na água. Isso significa saber o local do afogamento.Em comparação com outras tecnologias, fornecemos um protocolo de extração de DNA de diatomáceas simples, conveniente e econômico que podemos usar melhor em pesquisas forenses, especialmente na prática forense básica. N...