A mild traumatic brain injury (mTBI) can increase the risk of neurodegenerative-related disease, and serious long-term outcomes are often overlooked. In forensic science, the accurate identification of mTBIs can directly affect the application of evidence in practice cases. Recent research has revealed that the oral cavity and fecal microbiota play a fundamental role in deeply interconnecting the gut and brain injury. Therefore, we investigated the relationship between the temporal changes of the oral cavity and fecal bacterial communities with damage identification and post-injury time estimation after mTBI. In this study, we analyzed the oral cavity and fecal bacterial communities in mTBI rats under 12 different post-injury times (sham, 0 h, 2 h, 6 h, 12 h, 24 h, 2 d, 3 d, 5 d, 7 d, 10 d, and 14 d post-injury) using 16S rRNA sequencing technology. The sequence results revealed bacteria belonging to 36 phyla, 82 classes, 211 orders, 360 families, 751 genera, and 1398 species. Compared to the sham group, the relative abundance of the bacterial communities varied markedly in the post-injury groups. Importantly, our data demonstrated that Fusobacteria, Prevotellaceae, Ruminococcaceae, and Lactobacillaceae might be the potential candidates for mTBI identification, and 2 h post-injury was a critical time point to explore the temporal changes of mTBI injury-time estimation. The results also provide new ideas for mTBI treatment in the clinic.

Background Mild traumatic brain injury (mTBI) could increase the risk of neurodegenerative-related diseases, and the serious long-term outcomes were often overlooked. The accurate identification of mTBI became fully urgent for the diagnosis and prevention of the long-term outcomes. In forensic science, the accurate identification of mTBI will directly affect the application of evidences in practice case. Recent researches have revealed that oral cavity and fecal microbiota played a fundamental role in deeply interconnecting gut and brain injury prevention and recovery by regulating immune homeostasis and neuroinflammation. Therefore, we investigated the relationship between the temporal changes of oral cavity and fecal bacterial communities and damage identification and post-injury time estimation after mTBI. Results In this study, we analyzed the oral cavity and fecal bacterial communities in mTBI rats under the 12 different post-injury times (sham, 0 h, 2 h, 6 h, 12 h, 24 h, 2 d, 3 d, 5 d, 7 d, 10 d, 14 d post-injury) using 16s rRNA sequencing technology. The sequence results revealed bacteria belonging to 36 phyla, 82 classes, 211 orders, 360 families, 751 genera, and 1398 species. Compared to the sham group, the relative abundance of the bacterial communities varied markedly in the post-injury groups. Conclusions Importantly, our data demonstrated that Fusobacteria, Prevotellaceae, Ruminococcaceae, and Lactobacillaceae might be the potential candidates for mTBI identification and the 2 h post-injury was a critical time point to explore the temporal changes of mTBI injury-time estimation. And the results could also provide new ideas for mTBI treatment in the clinic.

Sarcophaga caerulescens (Zetterstedt 1838) (Diptera: Sarcophagidae) belongs to Sarcophagidae, which is closely associated with human life in ecological habits and has a clear environmental preference. Sarcophaga caerulescens can be better correlated with migration and postmortem interval (PMI) inference in forensic practice. In this study, we reported the complete mitochondrial genome (mitogenome) of S. caerulescens . The length of this mitogenome was 15,720 bp in total (GenBank accession No. MW551788), containing 13 protein-coding genes (PCGs), 2 ribosomal RNAs (rRNAs), 22 transfer RNAs (tRNAs), and a non-coding control region. Its nucleotide composition was A (39.7%), C (14.1%), G (9.4%), and T (36.9%). The phylogenetic relationships indicated that the species of S. caerulescens was closely related to S. similis . This study provides the mitochondrial data of S. caerulescens for further study of mitochondrial genome and enriches our understanding of the phylogenetic relationship of sarcophagid flies.

Necrodes littoralis (Linnaeus, 1758) (Coleoptera: Silphidae) is recognized as an important forensically beetle species. In this study, we report the mitogenome of N. littoralis. The total length of the mitogenome was 17,830bp (GenBank accession no. MW415274). Two ribosomal RNAs, 13 protein-coding genes, 22 transfer RNAs and a non-coding control region were identified. The base composition of N. littoralis was A (39.27%), G (9.49%), T (37.03%), and C (14.21%), respectively. Phylogenetic analysis indicated that N. littoralis is closely related to Diamesus osculans.

Neomyia cornicina (Fabricius, 1781) (Diptera: Muscidae) is considered to be an important dung-degrading species in Japan. In this study, we report the first mitochondrial genome (mitogenome) of N. cornicina . The complete mitogenome of N. cornicina was 17,254 bp in length (GenBank accession No. MW592695), containing 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, 2 ribosomal RNA (rRNA) genes, and a non-coding AT-rich region. Its nucleotide composition was A (41.0%), G (8.4%), C (11.8%), and T (38.8%). Phylogenetic analysis indicated that N. cornicina is closely related to the species of Eudasyphora canadiana . This mitogenome contributes useful information for further understanding of the phylogenetic relationship and species identification within Muscidae species.