Endurance Training in Humans Modulates the Bacterial DNA Signature of Skeletal Muscle

Accumulating evidence supports the existence of a tissue microbiota, which may regulate the physiological function of tissues in normal and pathological states. To gain insight into the regulation of tissue-borne bacteria in physiological conditions, we quantified and sequenced the 16S rRNA gene in aseptically collected skeletal muscle and blood samples from eight healthy male individuals subjected to six weeks of endurance training. Potential contamination bias was evaluated and the taxa profiles of each tissue were established. We detected bacterial DNA in skeletal muscle and blood, with background noise levels of detected bacterial DNA considerably lower in control versus tissue samples. In both muscle and blood, Proteobacteria, Actinobacteria, Firmicutes and Bacteroidetes were the most prominent phyla. Endurance training changed the content of resident bacterial DNA in skeletal muscle but not in blood, with Pseudomonas being less abundant, and both Staphylococcus and Acinetobacter being more abundant in muscle after exercise. Our results provide evidence that endurance training specifically remodels the bacterial DNA profile of skeletal muscle in healthy young men. Future investigations may shed light on the physiological impact, if any, of training-induced changes in bacterial DNA in skeletal muscle.

Efficient DNA Sampling in Burglary Investigations

In terms of crime scene investigations by means of forensic DNA-analyses, burglaries are the number one mass crime in Switzerland. Around one third of the DNA trace profiles registered in the Swiss DNA database are related to burglaries. However, during the collection of potential DNA traces within someone’s residence after a burglary, it is not known whether the sampled DNA originated from the perpetrator or from an inhabitant of said home. Because of the high incidence of burglaries, crime scene investigators usually do not collect reference samples from all the residents for economical and administrative reasons. Therefore, the presumably high probability that a DNA profile belonging to a person authorized to be at the crime scene ends up being sent to a DNA database for comparison, has to be taken into account. To our knowledge, no investigation has been made to evaluate the percentage of these non-perpetrator profiles straying into DNA databases. To shed light on this question, we collected reference samples from residents who had been victims of recent burglaries in their private homes. By comparing the profiles established from these reference samples with the profiles generated from trace DNA, we can show that the majority of the DNA samples collected in burglary investigations belong to the residents. Despite the limited number of cases included in the study, presumably due to a crime decline caused by the pandemic, we further show that trace DNA collection in the vicinity of the break and entry area, in particular window and door glasses, is most promising for sampling perpetrator instead of inhabitant DNA.

Finding Needle in the Haystack: “Kasur’s Bogeyman” Brought to Justice by Geographic Profiling and Mass DNA Screening

This article describes the application of the concept of geographic profiling in hunting a serial child rapist in Kasur, Pakistan. It also discusses, how DNA became the prime witness against the serial rapist in the court of law. In January 2018, the blind rape and murder case of Zainab Amin hit the headlines. Following autopsy and the subsequent forensic examination, the only piece of evidence, the agencies had, was the DNA profile of the perpetrator and the information that the source of DNA profile is a serial child rapist, involved in at least seven more cases. The analysis of all crime sites and the distance between them strongly suggested that the offender most likely was a local resident. Mass DNA screening in the target region was conducted by CSI teams of Punjab forensic science agency. The DNA matched with suspect number 814 who later confessed all his crimes. In Polygraph examination, the offender revealed his modus operandi which was in line with the hypotheses made during the geographic profiling of the crime scenes. Thus, geographic profiling proved to be a very useful investigative tool in predicting the probable location of the criminal involved in a series of crimes.

The assessment of the efficacy of STRs panels recommended by the ISAG for canine pedigrees analysis for forensic casework

Canine DNA is widely used in forensic investigations, particularly in dog attacks cases on humans. Nowadays, STR markers are employed worldwide in forensic laboratories to test human and animal genotypes. In the study we analysed the effectiveness of panel – 18 STR as previously recommended by ISAG and the same panel with three additional markers – 21 STR, which has been recommended by ISAG as the core panel for dog identification since 2016. We calculated the PD, PID for these sets of panels and estimated RMP based on the DNA profile obtained during an investigation of a woman bitten by a dog. The high combined CPD value for 18 and 21 STRs showed values close to 1.0. The CPID value for theses panels was 5.2 × 10−10 to 6.4 × 10−14. Statistical analysis estimated the random DNA match, in the case of the woman bitten by a dog, with a probability of 4.3×1019 and 2.8×1022, using 18 and 21 STR panels respectively, and that the canine DNA profile from the crime scene originated from the suspected dog and not from another random dog. Our results show that both STR panels can be used effectively for individual identification and forensic casework.

Proliferation Pattern of Pediatric Tumor-Derived Mesenchymal Stromal Cells and Role in Cancer Dormancy: A Perspective of Study for Surgical Strategy

The explanation for cancer recurrence still remains to be fully elucidated. Moreover, tumor dormancy, which is a process whereby cells enter reversible G0 cell cycle arrest, appears to be a critical step in this phenomenon. We evaluated the cell cycle proliferation pattern in pediatric tumor-derived mesenchymal stromal cells (MSCs), in order to provide a better understanding of the complex mechanisms underlying cancer dormancy. Specimens were obtained from 14 pediatric patients diagnosed with solid tumors and submitted to surgery. Morphology, phenotype, differentiation, immunological capacity, and proliferative growth of tumor MSCs were studied. Flow cytometric analysis was performed to evaluate the cell percentage of each cell cycle phase. Healthy donor bone marrow-derived mesenchymal stromal cells (BM-MSCs) were employed as controls. It was noted that the DNA profile of proliferating BM-MSC was different from that of tumor MSCs. All BM-MSCs expressed the typical DNA profile of proliferating cells, while in all tumor MSC samples, ≥70% of the cells were detected in the G0/G1 phase. In particular, seven tumor MSC samples displayed intermediate cell cycle behavior, and the other seven tumor MSC samples exhibited a slow cell cycle. The increased number of tumor MSCs in the G0–G1 phase compared with BM-MSCs supports a role for quiescent MSCs in tumor dormancy regulation. Understanding the mechanisms that promote dormant cell cycle arrest is essential in identifying predictive markers of recurrence and to promote a dedicated surgical planning.

Source Level Attribution: DNA Profiling from the ABAcard® HemaTrace® Kit

ABAcard® HemaTrace® kits have been used for crime scene stains for confirmation of human blood for many years. However, when the stain is too small to allow for separate testing, confirmatory testing may be forgone to preference DNA analysis. This can lead to court challenges as to the biological source and therefore probative value of the DNA profile. This research aimed to develop a protocol for DNA analysis of a minute blood stain subsequent to HemaTrace® testing. Stains were collected and subjected to HemaTrace® testing. Swabs were then removed from the HemaTrace® buffer solution and processed. DNA yields and STR DNA profiles were analysed for both quantity and quality. Full profiles were reliably obtained from stains with diameters of 0.6 mm–0.7 mm, reflecting DNA concentrations between 0.0036 ng/μL and 0.007 ng/μL, varying according to substrate characteristics. However, stains below a diameter of 0.6 mm should proceed directly for DNA profiling. This protocol was also successfully performed on blood stains which had undergone UV irradiation, although use of the reporting peak height threshold (lower than the routine analytical threshold) was required to obtain useable profiles. We have been able to demonstrate a protocol which, with minor adjustments to crime scene procedures, allows for both the confirmation of the presence of human blood, together with the generation of useful DNA profiles.

Genome-wide autosomal, mtDNA, and Y chromosome analysis of King Bela III of the Hungarian Arpad dynasty

The ancient Hungarians, “Madzsars”, established their control of the Carpathian Basin in the late ninth century and founded the Hungarian Kingdom around 1000AD. The origin of the Magyars as a tribal federation has been much debated in the past. From the time of the conquest to the early fourteenth century they were ruled by descendants of the Arpad family. In order to learn more about the genetic origin of this family, we here analyzed the genome of Bela III one of the most prominent members of the early Hungarian dynasty that ruled the Hungarian Kingdom from 1172 to 1196. The Y-Chromosome of Bela III belongs to haplogroup R1a-Z2123 that is today found in highest frequency in Central Asia, supporting a Central Asian origin for the ruling lineage of the Hungarian kingdom. The autosomal DNA profile of Bela III, however, falls within the genetic variation of present-day east European populations. This is further supported through his mtDNA genome that belongs to haplogroup H, the most common European maternal lineage, but also found in Central Asia. However, we didn’t find an exact haplotype match for Bela III. The typical autosomal and maternal Central Eastern European ancestry among Bela III autosomes might be best explained by consecutive intermarriage with local European ruling families.

The Application of The Skin Virome for Human Identification

The use of skin virome for human identification purposes offers a unique approach to instances where a viable and statistically relevant human DNA profile is unavailable. The human skin virome may act as an alternative DNA profile and/or an additional form of probative genetic material. To date, no study has attempted to investigate the human virome over a time series across various physical locations of the body to identify its potential as a tool for human identification. For this study, we set out to evaluate the stability, diversity, and individualization of the human skin virome. An additional goal was to identify viral signatures that can be used in conjunction with traditional forensic STR loci. In order to accomplish this, human virome metagenomes were collected and sequenced from 42 individuals at three anatomical locations (left hand, right hand, and scalp) across multiple collections periods over a 6-month window of time. Assembly dependent and independent bioinformatic approaches were employed, along with a database-based assessment, which resulted in three sets of stable putative viral markers. In total, with the three sets combined, 59 viral species and uncharacterized viral genome assemblies were identified as being significantly stable (P=5.3×10-15). Viral diversity, based on presence or absence, is significantly different across subjects (P<0.001). Here we demonstrate that not only is the human virome applicable to be used for human identification, but we have identified many viral signatures that can be used for forensic applications, thus providing a foundation to the novel field of forensic virology.HighlightsHere we provide the largest human skin virome study, to date. Our study revealed novel diversity findings of high abundance for certain viral taxa, for example, the Cress-like DNA phages, that have not previously been characterized in human skin viral ecology studies.There were 59 putative human skin viral biomarkers suitable for human identification from the core stable human skin virome of 42 subjects.The putative markers we identified were significantly stable over a 6-month period of time within individuals and across three autosomal locations of left hand, right hand, and scalp.Diversity of profiles, based on the presence and absence of our putative marker data set, were significantly different across test subjects.

The human intervertebral disc as a source of DNA for molecular identification

Genetic analyses such as STR-typing are routinely used for identification purposes in forensic casework. Although genotyping techniques only require a minimum amount of DNA to provide a genetic profile, DNA quality differs not only between but also within tissues during ongoing decomposition. Initiated by a recent case where, due to the constitution of the body, preferred tissue was not available or only resulted in a partial and not usable DNA profile, the analysis of intervertebral discs as a source of DNA was considered. As the analysis of this tissue resulted in a high quality DNA profile a further study was performed in which thirty intervertebral discs dissected from bodies in different stages of decay were analyzed. All samples yielded good quality DNA in quantities suitable for STR-based amplification with no or only low degradation indices, resulting in complete genetic profiles. These results demonstrate the robustness of human intervertebral disc tissue as a source of DNA for molecular identification purposes.