A comparative in situ decomposition study using still born piglets and leaf litter from a deciduous forest

A cadaver and dead plant organic matter, or litter, are rich energy sources that undergo a complex decomposition process, which impact the surrounding environmental microbiota. Advances in molecular microbiology techniques, with study of the 16S RNA genes, in particular, have highlighted the application of forensic ecogenomics in addressing key knowledge gaps. To investigate subsurface microbiome shifts as a novel tool to establish “postmortem microbial clock” and augment postmortem interval (PMI) and time-since-burial estimations, an in situ study with triplicate underground burials of piglets as human taphonomic proxies and Quercus robur leaf litter was monitored for 270 days. Changes in microbial community structure and composition were related directly to changes in seasonal temperature, with microbial shifts more pronounced during the summer. For example, Methylococcaceae could be used as seasonal bacterial indicators, from winter to summer, in establishing postmortem microbial clock for this site. Furthermore, Methylophilaceae (Methylophilales order) and Anaerolineaceae would differentiate for the piglet and leaf litter soils, respectively, 180 days after internment

Soil metabarcoding identifies season indicators and differentiators of pig and Agrostis/Festuca spp decomposition

To gain a better understanding of how environmental microbiota respond to cadaver decomposition, a forensic ecogenomic study was made with soil only control and 4 g each of S. scrofa domesticus and plant litter (Agrostis/Festuca spp) buried individually in a sandy clay loam (80 g) in sealed but perforated triplicate microcosms. The next-generation sequencing (Illumina Miseq) of the soil bacteria (16S rRNA gene) clade revealed seasonal taxomonic shifts at genus-level for the pig and plant litter microcosms compared to the non-burial controls. In particular, numerical abundances of Sphingobacterium (5.9%) and Pedobacter (24.1%) for the pig microcosms, and Rhodanobacter (18.1%) and Shinella (4.6%) for the plant litter microcosms, identified bacterial genera that could be tracked to establish a (seasonal) subsurface postmortem microbial clock. Also, family-level resolution revealed members that were unique to the control, grass and pig soils after 365 days

Shifts in soil biodiversity-A forensic comparison between Sus scrofa domesticus and vegetation decomposition

In a forensic context, microbial-mediated cadaver decomposition and nutrient recycling cannot be overlooked. As a result, forensic ecogenomics research has intensified to gain a better understanding of cadaver/soil ecology interactions as a powerful potential tool for forensic practitioners. For this study, domestic pig (Sus scrofa domesticus) (4 g) and grass (Agrostis/Festuca spp) cuttings (4 g) were buried (July 2013 to July 2014) in sandy clay loam (80 g) triplicates in sealed microcosms (127 ml; 50 × 70 cm) with parallel soil only controls. The effects of the two carbon sources were determined by monitoring key environmental factors and changes in soil bacterial (16S rRNA gene) and fungal (18S rRNA gene) biodiversity. Soil pH changes showed statistically significant differences (p 0.05) was observed between the treatments

Assessment of knowledge and practice of oxygen therapy among doctors and nurses: A survey from Ondo State, Southwest Nigeria

Objectives: Oxygen is among the commonly used drugs in acute emergencies. Prescription and administration of oxygen in emergencies by healthcare providers are reported to be inappropriate in most settings. There is a huge gap in the knowledge of health-care providers on various aspects of oxygen therapy. The purpose of this study was to assess the knowledge and practice of oxygen therapy among doctors and nurses working in Ondo State, South-West Nigeria and see how it compares with standard practice with a view to improving the quality care in this regard.Materials and Methods: A descriptive cross-sectional study was employed. The data were collected electronically using the Monkey survey application from consenting doctors and nurses through a self-administered validated and structured questionnaire. The questionnaire included the professional characteristics, educational background, awareness and use of oxygen therapy guidelines, knowledge of oxygen, indication for acute oxygen, and oxygen delivery practices. Data were analyzed using descriptive statistics and association between variables explored with Chi-square test at P < 0.05.Results: One hundred and seventy-six health workers participated in the study with mean age of 37.30 ± 8.88 years. One hundred and twelve (63.60%) of the respondents were doctors while 64 (36.40%) of the respondents were nurses. Sixty-eight (60.70%) of the doctors and 19 (29.70%) of nurses had a high level of knowledge of oxygen therapy (p<0.001). About half of both doctors and nurses had a poor practice level of oxygen therapy. The duration of oxygen administration (how long ago the respondent was involved in oxygen use and previous to formal training on oxygen therapy) were significantly associated with level of knowledge of oxygen therapy (p<0.001, 0.017).Conclusion: Results from this study suggest that the level of knowledge was high in about half of the respondents and about the same percentage had poor oxygen therapy practice in hospitals in Ondo State, South West Nigeria. Therefore, regular training of healthcare workers should be encouraged to update their knowledge and practice of oxygen therapy

Soil fungal community shift evaluation as a potential cadaver decomposition indicator

Fungi metabolise organic matter in situ and so alter both the bio-/physico-chemical properties and microbial community structure of the ecosystem. In particular, they are responsible reportedly for specific stages of decomposition. Therefore, this study aimed to extend previous bacteria-based forensic ecogenomics research by investigating soil fungal community and cadaver decomposition interactions in microcosms with garden soil (20 kg, fresh weight) and domestic pig (Sus scrofa domesticus) carcass (5 kg, leg). Soil samples were collected at depths of 0–10 cm, 10–20 cm and 20–30 cm on days 3, 28 and 77 in the absence (control −Pg) and presence (experimental +Pg) of Sus scrofa domesticus and used for total DNA extraction and nested polymerase chain reaction and denaturing gradient gel electrophoresis (PCR–DGGE) profiling of the 18S rRNA gene. The Shannon–Wiener (H′) community diversity indices were 1.25 ± 0.21 and 1.49 ± 0.30 for the control and experimental microcosms, respectively, while comparable Simpson species dominance (S) values were 0.65 ± 0.109 and 0.75 ± 0.015. Generally, and in contrast to parallel studies of the bacterial 16S rRNA and 16S rDNA profiles, statistical analysis (t-test) of the 18S dynamics showed no mathematically significant shifts in fungal community diversity (H′; p = 0.142) and dominance (S; p = 0.392) during carcass decomposition, necessitating further investigations

Changes to soil bacterial profiles as a result of Sus scrofa domesticus decomposition

The importance of cadaver decomposition knowledge for clandestine grave location cannot be over emphasised. Notwithstanding this, only a limited understanding is available on the resulting soil microbial community dynamics. To address this paucity, a pig leg (Sus scrofa domesticus; 5 kg) was buried in freshly weighed (20 kg) sandy loamy soil in a sealed microcosm (40 cm height) in parallel with a soil only control. Both microcosms were perforated nine times at equal distances and maintained outside. Soil samples were collected through these perforations from the top (0–10 cm), middle (10–20 cm) and bottom (20–30 cm) segments every three days for the first two weeks, and then weekly up to 14 weeks. PCR-DGGE gels quantified by 1D Phoretix showed increases in the cumulative soil community richness values of 43, 66 and 106 for the top, middle and bottom segments, respectively, in the presence of Sus scrofa domesticus. Shannon–Wiener's (H′) and Simpon's (D) indices confirmed corresponding species diversity increases in the middle (H′ = 1.58–2.33; D = 0.79–0.91) and bottom (H′ = 2.48–3.16; D = 0.85–0.95) depths between days 10 and 71 compared with the control. In contrast, similar evenness was recorded for all segments in both the Sus scrofa domesticus and control soils

2016 Research & Innovation Day Program

A one day showcase of applied research, social innovation, scholarship projects and activities.https://first.fanshawec.ca/cri_cripublications/1003/thumbnail.jp

Profiling of Successional Microbial Community Structure and Composition to Identify Exhumed Gravesoil—A Preliminary Study

Advancements in molecular microbial ecology techniques have enabled researchers to study the complex interactions of epinecrobiome, necrobiome, and thanatomicrobiome communities during cadaver decomposition within novel forensic disciplines. This preliminary study tracks shifts in subsurface soil necrobiome as indicators of time-since-exhumation where whole juvenile Sus scrofa domesticus was used as the human cadaver proxy. Principal component analysis of DGGE-based diversity index (Shannon-Weiner, HꞋ; Simpson (D)) measurements showed more consistent delineation of pre- and post-exhumation periods of the fungal 18S gene with further clustering for days 270 and 300. More importantly, high-resolution metabarcoding of the 16S rRNA gene recorded temporal bacterial clock indicators at order and family levels. Specifically, Xanthomonadales (11.29%) and Xanthomonadaceae (4.27%), and Verrucomicrobiaceae (4.00%) were abundance-based season (spring–summer) and microbial clock indicators for post-burial interval (PBI) ≥ 150 days. Hydrogenophilales (7.13%) and Hydrogenophilaceae (7.56%), Clostridiales (4.57%) and Clostridiaceae_1 (3.13%), and Bacteroidales (3.33%) defined the impacts of 120 days since exhumation of Sus scrofa domesticus. They could, therefore, be tracked to identify grave emptying for the current soil type

Profiling of successional microbial community structure and composition to identify exhumed gravesoil – A preliminary study

Advancements in molecular microbial ecology techniques have enabled researchers to study the complex interactions of epinecrobiome, necrobiome, and thanatomicrobiome communities during cadaver decomposition within novel forensic disciplines. This preliminary study tracks shifts in subsurface soil necrobiome as indicators of time-since-exhumation where whole juvenile Sus scrofa domesticus was used as the human cadaver proxy. Principal component analysis of DGGE-based diversity index (Shannon-Weiner, H0; Simpson (D)) measurements showed more consistent delineation of pre- and post-exhumation periods of the fungal 18S gene with further clustering for days 270 and 300. More importantly, high-resolution metabarcoding of the 16S rRNA gene recorded temporal bacterial clock indicators at order and family levels. Specifically, Xanthomonadales (11.29%) and Xanthomonadaceae (4.27%), and Verrucomicrobiaceae (4.00%) were abundance-based season (spring–summer) and microbial clock indicators for post-burial interval (PBI) ≥ 150 days. Hydrogenophilales (7.13%) and Hydrogenophilaceae (7.56%), Clostridiales (4.57%) and Clostridiaceae_1 (3.13%), and Bacteroidales (3.33%) defined the impacts of 120 days since exhumation of Sus scrofa domesticus. They could, therefore, be tracked to identify grave emptying for the current soil type