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Vavilov AY, Khalikov AA, Rykunov IA, Kuznetsov KO, Sagidullin RH. [Determination of the corpse's stay in the water duration according to maceration degree of its skin]. Sud Med Ekspert 2023; 66:64-68. [PMID: 37192463 DOI: 10.17116/sudmed20236603164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
A serious problem during the postmortem examination of a corpse extracted from the water can be a significant determination of its stay in the water duration. First of all, the signs indicating the presence of a corpse in the water include maceration, according to the severity of which forensic experts often determine how long the corpse stayed in the water. The aim of the study is to summarize the available literature data and propose ways to objectify the determination of a corpse's stay in water duration by the severity of skin maceration. In this article, based on the analysis of literature, the process of skin maceration is described, as well as the timing and speed of its development according to various authors. The presence of quite a large number of external and internal factors affecting the process of skin maceration and the subjectivity of its severity assessment is indicated. This article provides examples of the biophysical methods usage for the study of biological objects in forensic medical examination, allowing to objectively record changes in the researcher's parameter of interest. The use of skin impedancemetry to objectify the severity of skin maceration.
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Affiliation(s)
| | | | - I A Rykunov
- Izhevsk State Medical Academy, Izhevsk, Russia
| | - K O Kuznetsov
- Bashkir State Medical University, Ufa, Russia
- N.I. Pirogov Russian National Research Medical University, Moscow, Russia
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Cui C, Song Y, Mao D, Cao Y, Qiu B, Gui P, Wang H, Zhao X, Huang Z, Sun L, Zhong Z. Predicting the Postmortem Interval Based on Gravesoil Microbiome Data and a Random Forest Model. Microorganisms 2022; 11:microorganisms11010056. [PMID: 36677348 PMCID: PMC9860995 DOI: 10.3390/microorganisms11010056] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/11/2022] [Accepted: 12/20/2022] [Indexed: 12/28/2022] Open
Abstract
The estimation of a postmortem interval (PMI) is particularly important for forensic investigations. The aim of this study was to assess the succession of bacterial communities associated with the decomposition of mouse cadavers and determine the most important biomarker taxa for estimating PMIs. High-throughput sequencing was used to investigate the bacterial communities of gravesoil samples with different PMIs, and a random forest model was used to identify biomarker taxa. Redundancy analysis was used to determine the significance of environmental factors that were related to bacterial communities. Our data showed that the relative abundance of Proteobacteria, Bacteroidetes and Firmicutes showed an increasing trend during decomposition, but that of Acidobacteria, Actinobacteria and Chloroflexi decreased. At the genus level, Pseudomonas was the most abundant bacterial group, showing a trend similar to that of Proteobacteria. Soil temperature, total nitrogen, NH4+-N and NO3--N levels were significantly related to the relative abundance of bacterial communities. Random forest models could predict PMIs with a mean absolute error of 1.27 days within 36 days of decomposition and identified 18 important biomarker taxa, such as Sphingobacterium, Solirubrobacter and Pseudomonas. Our results highlighted that microbiome data combined with machine learning algorithms could provide accurate models for predicting PMIs in forensic science and provide a better understanding of decomposition processes.
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Affiliation(s)
- Chunhong Cui
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
- College of Resource and Environment, Nanjing Agricultural University, Nanjing 210095, China
| | - Yang Song
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Dongmei Mao
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Yajun Cao
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Bowen Qiu
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Peng Gui
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Hui Wang
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Xingchun Zhao
- Institute of Forensic Science, Ministry of Public Security, Beijing 100038, China
- Key Laboratory of Forensic Genetics of Ministry of Public Security, Beijing 100038, China
- Correspondence: (X.Z.); (Z.H.); (L.S.)
| | - Zhi Huang
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
- Correspondence: (X.Z.); (Z.H.); (L.S.)
| | - Liqiong Sun
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
- Correspondence: (X.Z.); (Z.H.); (L.S.)
| | - Zengtao Zhong
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
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Martlin BA, Anderson GS, Bell LS. A review of human decomposition in marine environments. CANADIAN SOCIETY OF FORENSIC SCIENCE JOURNAL 2022. [DOI: 10.1080/00085030.2022.2135741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Britny A. Martlin
- Centre for Forensic Research, School of Criminology, Simon Fraser University, Burnaby, BC, Canada
| | - Gail S. Anderson
- Centre for Forensic Research, School of Criminology, Simon Fraser University, Burnaby, BC, Canada
| | - Lynne S. Bell
- Centre for Forensic Research, School of Criminology, Simon Fraser University, Burnaby, BC, Canada
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Dmitrijs F, Guo J, Huang Y, Liu Y, Fang X, Jiang K, Zha L, Cai J, Fu X. Bacterial Succession in Microbial Biofilm as a Potential Indicator for Postmortem Submersion Interval Estimation. Front Microbiol 2022; 13:951707. [PMID: 35942315 PMCID: PMC9356301 DOI: 10.3389/fmicb.2022.951707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 06/13/2022] [Indexed: 11/18/2022] Open
Abstract
Bacteria acts as the main decomposer during the process of biodegradation by microbial communities in the ecosystem. Numerous studies have revealed the bacterial succession patterns during carcass decomposition in the terrestrial setting. The machine learning algorithm-generated models based on such temporal succession patterns have been developed for the postmortem interval (PMI) estimation. However, the bacterial succession that occurs on decomposing carcasses in the aquatic environment is poorly understood. In the forensic practice, the postmortem submersion interval (PMSI), which approximately equals to the PMI in most of the common drowning cases, has long been problematic to determine. In the present study, bacterial successions in the epinecrotic biofilm samples collected from the decomposing swine cadavers submerged in water were analyzed by sequencing the variable region 4 (V4) of 16S rDNA. The succession patterns between the repeated experimental settings were repeatable. Using the machine learning algorithm for establishing random forest (RF) models, the microbial community succession patterns in the epinecrotic biofilm samples taken during the 56-day winter trial and 21-day summer trial were determined to be used as the PMSI predictors with the mean absolute error (MAE) of 17.87 ± 2.48 ADD (≈1.3 day) and 20.59 ± 4.89 ADD (≈0.7 day), respectively. Significant differences were observed between the seasons and between the substrates. The data presented in this research suggested that the influences of the environmental factors and the aquatic bacterioplankton on succession patterns of the biofilm bacteria were of great significance. The related mechanisms of such influence need to be further studied and clarified in depth to consider epinecrotic biofilm as a reliable predictor in the forensic investigations.
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Affiliation(s)
- Finkelbergs Dmitrijs
- Department of Forensic Science, School of Basic Medical Sciences, Central South University, Changsha, China
| | - Juanjuan Guo
- Department of Forensic Science, School of Basic Medical Sciences, Central South University, Changsha, China
- Department of Vascular Surgery, Shenzhen Second People's Hospital, The First Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Yecao Huang
- Department of Forensic Medicine, School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, China
| | - Yafei Liu
- Department of Forensic Medicine, School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, China
| | - Xinyue Fang
- Department of Forensic Medicine, School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, China
| | - Kankan Jiang
- Department of Forensic Medicine, School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, China
| | - Lagabaiyila Zha
- Department of Forensic Science, School of Basic Medical Sciences, Central South University, Changsha, China
| | - Jifeng Cai
- Department of Forensic Science, School of Basic Medical Sciences, Central South University, Changsha, China
- Jifeng Cai
| | - Xiaoliang Fu
- Department of Forensic Science, School of Basic Medical Sciences, Central South University, Changsha, China
- Department of Forensic Medicine, School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, China
- *Correspondence: Xiaoliang Fu
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Kaszubinski SF, Receveur JP, Nestle ED, Pechal JL, Benbow ME. Microbial community succession of submerged bones in an aquatic habitat. J Forensic Sci 2022; 67:1565-1578. [PMID: 35349167 DOI: 10.1111/1556-4029.15036] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 02/06/2022] [Accepted: 03/08/2022] [Indexed: 01/04/2023]
Abstract
After death, microbes (including bacteria and fungi) colonize carrion from a variety of sources during the decomposition process. The predictable succession of microbes could be useful for forensics, such as postmortem submersion interval estimation (PMSI) for aquatic deaths. However, gaps exist in our understanding of microbial succession on submerged bone, particularly regarding longer-term decomposition (>1 year), fungal composition, and differences between internal and external microbial communities. To further explore this potential forensic tool, we described the postmortem microbial communities (bacteria and fungi) on and within submerged bones using targeted amplicon sequencing. We hypothesized predictable successional patterns of microbial colonization would be detected on the surface and within submerged bones, which would eventually converge to a similar microbial community. To best replicate forensic contexts, we sampled bones from replicate swine (Sus scrofa domesticus) carcasses submerged in a freshwater pond, every three months for nearly two years. Microbial bone (internal vs. external) community structure (taxa abundance and diversity) of bones differed for both bacteria and fungi, but internal and external communities did not converge to a similar structure. PMSI estimation models built with random forest regression of postmortem microbiomes were highly accurate (>80% variation explained in PMSI) and showed promise for forensic purposes. Overall, we provide further evidence that internal and external bone microbial communities submerged in an aquatic habitat are distinct and each community undergoes predictable succession, demonstrating potential utility in forensics for modeling PMSI in unattended deaths and/or cold cases.
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Affiliation(s)
- Sierra F Kaszubinski
- Department of Integrative Biology, Michigan State University, East Lansing, Michigan, USA
| | - Joseph P Receveur
- Department of Entomology, Michigan State University, East Lansing, Michigan, USA.,Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, Michigan, USA
| | - Emily D Nestle
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Jennifer L Pechal
- Department of Entomology, Michigan State University, East Lansing, Michigan, USA
| | - M Eric Benbow
- Department of Entomology, Michigan State University, East Lansing, Michigan, USA.,Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, Michigan, USA.,Department of Osteopathic Medical Specialties, Michigan State University, East Lansing, Michigan, USA
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