Postmortem Interval Estimation and Validation Through a Comparative Study of South American Flies Reared in the Field Versus Laboratory Conditions

Abstract Studies under constant temperatures are the most common to estimate the Postmortem Interval (PMI). It is imperative that forensic sciences have data from studies carried out in the field. Therefore, this work aims to: (1) evaluate the parameters (weight, length, development time) associated with the life cycles of Lucilia ochricornis (Wiedemann) (Diptera: Calliphoridae) and Lucilia purpurascens (Walker) under experimental conditions in the field considering fluctuating temperatures, and (2) compare these results with those known and published by the same authors for cultures realized in the laboratory under constant temperatures; which will permit us to contrast the most widely used existing methodologies for forensic application in estimating the minimum postmortem interval (PMImin). For each season of the year, cultures of both species were made in the field, collecting information on temperature, humidity, and photoperiod to perform laboratory cultures, later comparing: development time, length, weight, and Accumulated Degree-Hours (ADH) in both types of cultures. Methods for estimating the PMI were obtained and validated with the information of the cultures grown in the field. The two types of cultures showed differences between each other for both species. The forensic use methods to estimate PMI were enhanced and their precision increased when maximum larval length data were used, and it was also concluded that feeding larval stages are the most accurate to be used in making estimates because the larva is growing. The estimation of the PMI through the use of necrophagous flies development remains reliable for obtaining the PMImin.

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Estimation of the Postmortem Interval Through the Use of Development Time of Two South American Species of Forensic Importance of the Genus Lucilia (Diptera: Calliphoridae)

Journal of Medical Entomology ◽

10.1093/jme/tjab001 ◽

2021 ◽

Author(s):

Ximena Acosta ◽

Andrea X González-Reyes ◽

José A Corronca ◽

Néstor D Centeno

Keyword(s):

Development Time ◽

Relevant Information ◽

Postmortem Interval ◽

The Other ◽

South American ◽

South American Species ◽

Brood Chamber ◽

Development Stages ◽

Forensic Expertise ◽

Long Time

Abstract Obtaining the specific development time of each species of forensic interest is crucial for the estimation of an accurate and reliable Minimum Postmortem Interval (PMImin). In Argentina, Lucilia ochricornis (Wiedemann) and Lucilia purpurascens (Walker) (Diptera: Calliphoridae) were masked under the name Lucilia cluvia (Walker) for a long time still in forensic expertise. For this reason, the objective of this work is to deepen the study of the development time of these species and utilize this relevant information in the generation of different associated methods that can be used in forensics to estimate the PMI. Immature stages of L. ochricornis and L. purpurascens were reared in a brood chamber according to the following temperature treatments: 13.4, 15.1, 22.3, and 23.6°C. The development time of each stage/state of these flies was recorded as well as the resulting accumulated degree-hours (ADH), to build isomorphen diagrams and thermal summation models for each species. The development time and ADH were different between both species and their development stages. On the other hand, the methods provided for estimating PMImin provide the forensic entomologist more tools to reach accurate and reliable estimates.

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PP2A-C may be a promising candidate for postmortem interval estimation

International Journal of Legal Medicine ◽

10.1007/s00414-020-02466-y ◽

2021 ◽

Author(s):

Jing Wang ◽

Gang Chen ◽

Hongyan Qian ◽

Qing Shang ◽

Jing Xiao ◽

...

Keyword(s):

Interval Estimation ◽

Postmortem Interval ◽

Promising Candidate

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Impact of the Human Microbiome in Forensic Sciences: a Systematic Review

Applied and Environmental Microbiology ◽

10.1128/aem.01451-20 ◽

2020 ◽

Vol 86 (22) ◽

Author(s):

Manuel G. García ◽

María D. Pérez-Cárceles ◽

Eduardo Osuna ◽

Isabel Legaz

Keyword(s):

Systematic Review ◽

Forensic Science ◽

Human Microbiome ◽

Geographical Location ◽

Postmortem Interval ◽

Forensic Sciences ◽

Content Type ◽

Microbiome Analysis ◽

Location Of Death ◽

Microbiome Research

ABSTRACT Numerous studies relate differences in microbial communities to human health and disease; however, little is known about microbial changes that occur postmortem or the possible applications of microbiome analysis in the field of forensic science. The aim of this review was to study the microbiome and its applications in forensic sciences and to determine the main lines of investigation that are emerging, as well as its possible contributions to the forensic field. A systematic review of the human microbiome in relation to forensic science was carried out by following PRISMA guidelines. This study sheds light on the role of microbiome research in the postmortem interval during the process of decomposition, identifying death caused by drowning or sudden death, locating the geographical location of death, establishing a connection between the human microbiome and personal items, sexual contact, and the identification of individuals. Actinomycetaceae, Bacteroidaceae, Alcaligenaceae, and Bacilli play an important role in determining the postmortem interval. Aeromonas can be used to determine the cause of death, and Corynebacterium or Helicobacter pylori can be used to ascertain personal identity or geographical location. Several studies point to a promising future for microbiome analysis in the different fields of forensic science, opening up an important new area of research.

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Molecular data reshape our understanding of the life cycles of three digeneans (Monorchiidae and Gymnophallidae) infecting the bivalve, Donax variabilis: it’s just a facultative host!

Parasite ◽

10.1051/parasite/2021027 ◽

2021 ◽

Vol 28 ◽

pp. 34

Author(s):

Kristina M. Hill-Spanik ◽

Claudia Sams ◽

Vincent A. Connors ◽

Tessa Bricker ◽

Isaure de Buron

Keyword(s):

Gulf Of Mexico ◽

Intermediate Host ◽

Atlantic Coast ◽

The United States ◽

Life Cycles ◽

Intermediate Hosts ◽

Larval Stages ◽

Complete Life Cycle ◽

Morphological Criteria ◽

Donax Variabilis

The coquina, Donax variabilis, is a known intermediate host of monorchiid and gymnophallid digeneans. Limited morphological criteria for the host and the digeneans’ larval stages have caused confusion in records. Herein, identities of coquinas from the United States (US) Atlantic coast were verified molecularly. We demonstrate that the current GenBank sequences for D. variabilis are erroneous, with the US sequence referring to D. fossor. Two cercariae and three metacercariae previously described in the Gulf of Mexico and one new cercaria were identified morphologically and molecularly, with only metacercariae occurring in both hosts. On the Southeast Atlantic coast, D. variabilis’ role is limited to being a facultative second intermediate host, and D. fossor, an older species, acts as both first and second intermediate hosts. Sequencing demonstrated 100% similarities between larval stages for each of the three digeneans. Sporocysts, single tail cercariae, and metacercariae in the incurrent siphon had sequences identical to those of monorchiid Lasiotocus trachinoti, for which we provide the complete life cycle. Adults are not known for the other two digeneans, and sequences from their larval stages were not identical to any in GenBank. Large sporocysts, cercariae (Cercaria choanura), and metacercariae in the coquinas’ foot were identified as Lasiotocus choanura (Hopkins, 1958) n. comb. Small sporocysts, furcocercous cercariae, and metacercariae in the mantle were identified as gymnophallid Parvatrema cf. donacis. We clarify records wherein authors recognized the three digenean species but confused their life stages, and probably the hosts, as D. variabilis is sympatric with cryptic D. texasianus in the Gulf of Mexico.

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Human postmortem interval estimation from vitreous potassium: an analysis of original data from six different studies

Journal of Clinical Forensic Medicine ◽

10.1016/1353-1131(95)90094-2 ◽

1995 ◽

Vol 2 (3) ◽

pp. 168

Author(s):

N Lange ◽

S Swearer ◽

W.Q Sturner

Keyword(s):

Interval Estimation ◽

Original Data ◽

Postmortem Interval

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Molecular characterization and structure of intestinal micro flora for postmortem interval estimation in SD rats

10.21203/rs.2.13736/v1 ◽

2019 ◽

Author(s):

Huan Li ◽

Lu Yuan ◽

Ruina Liu ◽

Siruo Zhang ◽

E Yang ◽

...

Keyword(s):

Bacterial Community ◽

High Throughput Sequencing ◽

Interval Estimation ◽

Pcr Amplification ◽

Postmortem Interval ◽

The Body ◽

Rrna Gene ◽

Variable Regions ◽

Time Points ◽

Almost All

Abstract Background The human rectum flora consists of a huge variety of bacteria and the association between individuals and their rectum bacterial community begins presently after birth and continues the whole lifetime. Once the body dies, the inherent microbes begin to break down from the inside and play a key role thereafter. Results The aim of this study was to investigate the probable shift of the rectum flora at different time intervals up to 15 days after death and to characterize the contribution for of this shift to estimate the time of death. The rectum of rats was wiped with a sterile cotton swab and the samples were proceeded for DNA extraction, PCR amplification of the 16S rRNA gene with the V3+V4 variable regions, and high throughput sequencing carried out on IonS5TMXL platform. The results were analyzed for intra-group and inter-group diversity, similarity and difference at different time points. At phylum level, Proteobacteria and Firmicutes showed major shifts, checked at 11 different intervals and emerged in the most of postmortem intervals. At the genus level, Enterococcus appeared in all groups except alive samples, Lactobacillus and Proteus appeared in most time points, and the latter showed an increasing trend after 3 days postmortem samples. At the species level, Enterococcus_faecalis and Proteus_mirabilis existed in most postmortem intervals, and the former had a downward trend after day 5 postmortem, while the latter had an upward trend. Corynebacterium_amycolatum , Entero_isolate_group_2 , Bacteroides_uniformis , Enterococcus_faecalis , Streptococcus_gallolyticus_subsp_macedonics , Clostridium_sporogenes were more abundant in 0-hour, day 1, 3, 5, 7, 13 postmortem intervals, respectively, while Proteus_mirabilis and Vagococcus_lutrae were abundant in day 15 postmortem. In addition, functional capacity analysis of Membrane_Transport, Amino_Acid_Metabolism, Nucleotide_Metabolism and Energy_Metabolism showed significant differences between alive and almost all other time points after death ( P <0.05). Conclusions All in all, bacteria at different levels (phylum, genera, species) showed different characteristic during the process of decomposition and possessed entirely different relative abundance and the structure of bacterial community in each time point shifted obviously, which suggested that the specific bacteria might imply the specific postmortem interval during decomposition.

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Life Cycles

Evolutionary Ecology ◽

10.1093/oso/9780195131543.003.0016 ◽

2001 ◽

Author(s):

Jan A. Pechenik

Keyword(s):

Life Cycle ◽

Genetic Material ◽

Life Cycles ◽

Offspring Size ◽

Free Living ◽

Complex Life Cycles ◽

Volume Number ◽

Larval Stages ◽

Underlying Mechanisms ◽

Life Cycle Evolution

I have a Hardin cartoon on my office door. It shows a series of animals thinking about the meaning of life. In sequence, we see a lobe-finned fish, a salamander, a lizard, and a monkey, all thinking, “Eat, survive, reproduce; eat, survive, reproduce.” Then comes man: “What's it all about?” he wonders. Organisms live to reproduce. The ultimate selective pressure on any organism is to survive long enough and well enough to pass genetic material to a next generation that will also be successful in reproducing. In this sense, then, every morphological, physiological, biochemical, or behavioral adaptation contributes to reproductive success, making the field of life cycle evolution a very broad one indeed. Key components include mode of sexuality, age and size at first reproduction (Roff, this volume), number of reproductive episodes in a lifetime, offspring size (Messina and Fox, this volume), fecundity, the extent to which parents protect their offspring and how that protection is achieved, source of nutrition during development, survival to maturity, the consequences of shifts in any of these components, and the underlying mechanisms responsible for such shifts. Many of these issues are dealt with in other chapters. Here I focus exclusively on animals, and on a particularly widespread sort of life cycle that includes at least two ecologically distinct free-living stages. Such “complex life cycles” (Istock 1967) are especially common among amphibians and fishes (Hall and Wake 1999), and within most invertebrate groups, including insects (Gilbert and Frieden 1981), crustaceans, bivalves, gastropods, polychaete worms, echinoderms, bryozoans, and corals and other cnidarians (Thorson 1950). In such life cycles, the juvenile or adult stage is reached by metamorphosing from a preceding, free-living larval stage. In many species, metamorphosis involves a veritable revolution in morphology, ecology, behavior, and physiology, sometimes taking place in as little as a few minutes or a few hours. In addition to the issues already mentioned, key components of such complex life cycles include the timing of metamorphosis (i.e., when it occurs), the size at which larvae metamorphose, and the consequences of metamorphosing at particular times or at particular sizes. The potential advantages of including larval stages in the life history have been much discussed.

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Larval development of the shrimp Hippolyte sapphica d’Udekem d’Acoz, 1993 forma A and B (Decapoda: Caridea: Hippolytidae) reared in the laboratory, confirmation of the conspecific status of the two forms

Zootaxa ◽

10.11646/zootaxa.2579.1.3 ◽

2010 ◽

Vol 2579 (1) ◽

pp. 45 ◽

Cited By ~ 3

Author(s):

ALEXANDROS NTAKIS ◽

CHRYSSA ANASTASIADOU ◽

ROMAN LIASKO ◽

IOANNIS D. LEONARDOS

Keyword(s):

Related Species ◽

Morphological Characters ◽

Experimental Conditions ◽

Closely Related Species ◽

Larval Stages ◽

Laboratory Confirmation ◽

Bibliographic Data ◽

Immature Form ◽

Complete Series ◽

First Time

The complete series of larval staging of Hippolyte sapphica d’Udekem d’Acoz, 1993 forma A and B from Louros estuary was studied in the laboratory and described in detail for the first time. The reared larvae of H. sapphica passed through six zoeal stages and one megalopal stage. The larval monitoring completed when the individuals could be assigned clearly to form A and B via rostra formation. Under the experimental conditions, the average durations of the larval stages were as follows: three days for 1 st and 2 nd stages, three to four days for 3 rd , 4 th , 5 th and 6 th stages, four days for the megalopal stage and 19 to 30 days for immature form A and B individuals. Comparison of the larval morphological characters among the described material and the bibliographic data of closely related species was made and discussed. The offspring of females of the forma A includes forma A and B and the same can be said of the offspring of the forma B. This confirms that the formae A and B are indeed conspecific.

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