Antimicrobial peptides (AMPs) are a class of templates with application potential for drug development. Amphibians are important sources of AMPs. Duttaphrynus melanostictus is the main source of traditional Chinese medicine “Chansu”, which has anti-infection effect while without a clear mechanism. This study aimed to find the cathelicidin peptide in D. melanostictus and then investigate the activity in vivo and in vitro, and an AMP-encoding gene (cathelicidin-DM, GenBank: KJ820824.1) was obtained from the constructed cDNA library of D. melanostictus. The MIC test and SYTOX Green uptake were used for the evaluation of the bactericidal capacity and mechanisms. The serum stability tests were used for the evaluation of the application potential. The skin wound infection model and in vivo imaging were used for in vitro application of possibility evaluation. The results showed that cathelicidin-DM was a 37 amino acid AMP with good bactericidal ability, which was similar to melittin: both can kill bacteria within 15 min. Moreover, cathelicidin-DM exhibits good therapeutic potential in the mouse wound infection model, and it can be enriched to the site of infection for treatment. Thus, cathelicidin-DM could be a new template for antimicrobial drug development given its good antibacterial activity in vivo and in vitro.

Background: Archaeological studies have revealed a series of cultural changes around the Last Glacial Maximum in East Asia; whether these changes left any signatures in the gene pool of East Asians remains poorly indicated. To achieve deeper insights into the demographic history of modern humans in East Asia around the Last Glacial Maximum, we extensively analyzed mitochondrial DNA haplogroup M9a'b, a specific haplogroup that was suggested to have some potential for tracing the migration around the Last Glacial Maximum in East Eurasia.Results: A total of 837 M9a'b mitochondrial DNAs (583 from the literature, while the remaining 254 were newly collected in this study) pinpointed from over 28,000 subjects residing across East Eurasia were studied here. Fifty-nine representative samples were further selected for total mitochondrial DNA sequencing so we could better understand the phylogeny within M9a'b. Based on the updated phylogeny, an extensive phylogeographic analysis was carried out to reveal the differentiation of haplogroup M9a'b and to reconstruct the dispersal histories.Conclusions: Our results indicated that southern China and/or Southeast Asia likely served as the source of some post-Last Glacial Maximum dispersal(s). The detailed dissection of haplogroup M9a'b revealed the existence of an inland dispersal in mainland East Asia during the post-glacial period. It was this dispersal that expanded not only to western China but also to northeast India and the south Himalaya region. A similar phylogeographic distribution pattern was also observed for haplogroup F1c, thus substantiating our proposition. This inland post-glacial dispersal was in agreement with the spread of the Mesolithic culture originating in South China and northern Vietnam.

Drug-resistant tuberculosis (DR-TB), especially multidrug-resistant tuberculosis (MDR-TB), is a serious medical and societal problem in China. The purpose of this study was to evaluate the mutation characteristics of drug-resistant Mycobacterium tuberculosis (M. tuberculosis) isolates in Yunnan, China. Drug susceptibility testing (DST) was performed in 523 clinical M. tuberculosis isolates. Six drug resistance genes (katG, inhA, rpoB, rpsL, embB, and pncA) were selected to screen for mutations. In total, 54 clinical M. tuberculosis strains were identified as drug-resistant by DST, including 18 single drug-resistant (SDR) strains and 36 multidrug-resistant (MDR) strains. Twenty-four types of mutations in five genes (excluding the inhA gene) were screened in forty-one strains. Six novel mutations were identified in this study, including three missense mutations (p.S302R in katG, p.D78G in embB, and p.M1I in pncA), two frameshift mutations (408 ins A and 538-580 del in pncA), and one mutation in a control region (-6 C>T located upstream of rpsL). The mutation frequencies in the hotspot mutation regions in the katG, rpoB, rpsL, embB, and pncA genes were 92.5%, 44.4%, 54.2%, 52.6%, and 37.5%, respectively. The mutation spectra and frequencies seemed somewhat unique in the Yunnan DR-TB strains.

Pseudomonas aeruginosa is one of the three most pathogenic bacteria that frequently cause life‑threatening opportunistic human infections, pneumonia, and lower respiratory tract infections in immunocompromised hosts, particularly in the burns ward. The present study aimed to establish a loop‑mediated isothermal amplification (LAMP) method for the rapid and sensitive detection of P. aeruginosa‑specific gene hypothetical protein (GenBank ID: 882161). The gene was obtained through local and online BLAST, and specific primers were designed for this gene. Reaction conditions were optimized at 65˚C for 30 min and 80˚C for 2 min, whereas the reaction system contained 5.2 mM Mg2+, 8 U Bst 2.0 DNA polymerase, 1.4 mM deoxyribonucleotide and 0.2 and 1.6 µM of the outer and inner primers, respectively. The LAMP method was evaluated using 150 P. aeruginosa and 170 non‑P. aeruginosa strains. Positive reactions were observed on 150 P. aeruginosa strains, whereas all non‑P. aeruginosa strains exhibited negative results. Plasmids with the specific gene and mouse blood with P. aeruginosa were used for sensitivity assay. The detection limit of LAMP was 1 bacterium/reaction. Results indicated that the LAMP method targeted to hypothetical protein is a fast, specific, sensitive, inexpensive and suitable method for detection of P. aeruginosa.

Leber hereditary optic neuropathy (LHON) is a mitochondrial disorder with gender biased and incomplete penetrance. The majority of LHON patients are caused by one of the three primary mutations (m.3460G > A, m.11778G > A and m.14484T > C). Rare pathogenic mutations have been occasionally reported in LHON patients.