An expanded description, natural history, and genetic variation of the recently described cobra species Naja fuxi Shi et al., 2022

The morphological variation, extended distribution, and sequence divergence of a recently described of cobra Naja fuxi Shi et al., 2022 captured from mountainous areas in Thailand are evaluated by using molecular and morphological analyses. We investigated the genetic variation and affinities of 72 specimens in the genus Naja by using mitochondrial DNA (cytochrome b and control region) and the nuclear DNA gene, C-mos. Morphological examination was conducted for 33 cobra specimens obtained from the northern, western, and north-eastern regions, and data on their natural history were gathered during field surveys. A high degree of genetic differentiation was shown to exist between the cobras collected from lowlands and those from mountainous areas. N. fuxi occurs in uplands bordering Thailand’s Central Basin, whereas the similar looking N. kaouthia Lesson, 1831 is more or less restricted to the lowlands. All phylogenetic and network analyses supported a distinct clade of N. fuxi from north, west, and, north-east regions. In addition, N. fuxi seems to exhibit a split between the north-eastern population and those from the north and west. The range of N. fuxi probably extends far into the mountainous areas of the neighbouring countries Myanmar, Laos, and Vietnam. Morphologically, N. fuxi in Thailand can be distinguished from all other cobra species in the adjacent Oriental Region. The speciation of cobras in Thailand likely reflects key events in the region’s geographical, climate and environmental history

cDNA cloning, sequencing, and expression of <img src='/image/spc_char/alpha.gif' border=0>- and <img src='/image/spc_char/beta.gif' border=0>-neurotoxins from Thai-Malayan krait

31-37 Amplification products of - and -neurotoxin from Thai-Malayan krait (Bungarus candidus) were cloned and expressed in TA expression vector. The expressed protein could not be distinguished by SDS-PAGE. Hence, immunoblotting was performed using AntiHis (C-term)-HRP antibody. The antibody could identify the histidine tags at 24 h incubation with 0.02% L-arabinose. To increase the expression level, PCR products were cloned into PCR2.1 cloning vector and pGEX2T expression vector. The optimal condition for protein expression was IPTG induction at 1 mM for 24 h. Neurotoxin fusion proteins were used as antigen to generate antibodies in mice. In vitro neutralization indicated that antibody against neurotoxin fusion proteins raised in mice was able to neutralize 2 LD50 of crude venom. This result provides basic data for the use of the neurotoxin fusion proteins as immunogens in the development of specific antivenoms against the B. candidus venom. </smarttagtype

Anticancer properties of phospholipase A2 fromDaboia siamensis venom on human skin melanoma cells

Abstract Background Phospholipase A2 (PLA2) is a major component of theDaboia siamensis venom, which is able to hydrolyse the membrane of various cells. For this reason, the activity of PLA2was investigated regarding its pharmaceutical properties. This study was conducted to explore the pharmacological properties of a PLA2from Daboia siamensis (dssPLA2) venom on human skin melanoma cell line (SK-MEL-28). Methods dssPLA2 was isolated by ion exchange and gel filtration columns. Various concentrations of dssPLA2were investigated for cytotoxic activity and inhibition of migration on SK-MEL-28 cells. Cell death analysis, mRNA expression levels of Notch I-III and BRAF V600E genes were also determined. Results dssPLA2 exhibited cytotoxicity on SK-MEL-28 for 24 and 72 h as compared with untreated cells. However, it had no toxic effects on CCD-1064sk cells under the same conditions. dssPLA2 (0.25 and 0.5 μg/mL) induced 17.16 and 30.60 % of apoptosis, while activated 6.53 and 7.05 % of necrotic cells. dssPLA2 at 0.25, 0.5, 1 and 2 μg/mL could inhibit migration on SK-MEL-28 cells for 24 h by 31.06, 41.66, 50 and 68.75 %, respectively. The action of dssPLA2 significantly reduced the levels of Notch I and BRAF V600E genes expression on SK-MEL-28 cells compared with untreated cells at 72 h. Conclusions This study indicates that dssPLA2 had potential effects of apoptosis, necrosis, cytotoxicity and inhibition of migration on SK-MEL-28 cells. dssPLA2 could possibly be a selective agent that targets cancer cells without affecting normal cells

Additional file 1: of Anticancer properties of phospholipase A2 from Daboia siamensis venom on human skin melanoma cells

Amount of SK-MEL-28 cells that could close a scratch within 24 h of incubation. (PDF 5480 kb

Interactions of PLA2-s from Vipera lebetina, Vipera berus berus and Naja naja oxiana Venom with Platelets, Bacterial and Cancer Cells

Secretory phospholipasesA2 (sPLA2s) form a large family of structurally related enzymes widespread in nature. Herein, we studied the inhibitory effects of sPLA2s from Vipera lebetina (VLPLA2), Vipera berus berus (VBBPLA2), and Naja naja oxiana (NNOPLA2) venoms on (i) human platelets, (ii) four different bacterial strains (gram-negative Escherichia coli and Vibrio fischeri; gram-positive Staphylococcus aureus and Bacillus subtilis) and (iii) five types of cancer cells (PC-3, LNCaP, MCF-7, K-562 and B16-F10) in vitro. sPLA2s inhibited collagen-induced platelet aggregation: VBBPLA2 IC50 = 0.054, VLPLA2 IC50 = 0.072, NNOPLA2 IC50 = 0.814 μM. p-Bromophenacylbromide-inhibited sPLA2 had no inhibitory action on platelets. 36.17 μM VBBPLA2 completely inhibited the growth of gram-positive Bacillus subtilis whereas no growth inhibition was observed towards gram-negative Escherichia coli. The inhibitory action of sPLA2s (~0.7 μM and ~7 μM) towards cancer cells depended on both venom and cell type. VBBPLA2 (7.2 μM) inhibited significantly the viability of K-562 cells and the cell death appeared apoptotic. The sPLA2s exhibited no inhibitory effect towards LNCaP cells and some effect (8%–20%) towards other cells. Thus, already sub-μM concentrations of sPLA2s inhibited collagen-induced platelet aggregation and from the current suite of studied svPLA2s and test cells, VBBPLA2 was the most growth inhibitory towards Bacillus subtilis and K-562 cells