The structure and antimicrobial potential of wasp and hornet (Vespidae) mastoparans: A review

Wasp venom is a complex mixture of biologically active components, including high molecular weight proteins, small peptides, bioactive amines, and amino acids. Peptides comprise up to 70% of dried venom. In social wasp venoms, three of the major peptide types are mastoparans, which cause mast cell degranulation, chemotactic peptides, which promote chemotaxis of polymorphonucleated leukocytes, and kinin‐related peptides, which are known to produce pain and increase vascular permeability. Among these, the bioactive tridecapeptide mastoparan is the most common and may even have antimicrobial activity. Herein we summarize the results of studies on vespid mastoparans, focusing on hornets (Vespa spp.) identified following a systematic literature search for mastoparans of hornets in the genus Vespa, the most active mastoparan research taxon. The common features of hornet mastoparans are C‐terminal amidation, amphipathic helical structure, and multiple functions such as mast cell degranulation and hemolysis, as well as membrane permeabilization. Most interestingly, all tested hornet mastoparans have strong antimicrobial activities, suggesting that they can provide useful insights into and opportunities for development of novel antibacterial peptides.     

DNA barcoding of the South Korean Tettigoniidae (Orthoptera) using collection specimens reveals three potential species complexes

We carried out DNA barcoding on 24 Korean tettigonid species of 19 genera deposited in the National Institute of Biological Resources to reevaluate the preliminary identification of each specimen. Sequence divergence of DNA barcodes obtained from 113 samples of the 24 species ranged from 0 to 30.4%, the intraspecific variation was 0–7.3%, and the interspecific divergence was 1.1–30.4%; we could not examine the barcoding gap. In the neighbor‐joining tree, the branch length among individuals of Tettigonia ussuriana, Paratlanticus ussuriensis, and Hexacentrus japonicus were relatively longer than those in other species. The detailed analysis of the morphological characters and DNA barcodes of the above three species revealed that these three species represent species complexes. The T. ussuriana complex comprised T. jungi, T. uvarovi, and T. ussuriana. Paratlanticus ussuriensis cluster contained four species; one cluster was identified as P. palgongensis based on morphological characteristics, but the other three clusters, including the P. ussuriensis cluster, require further detailed taxonomic analysis. Lastly, two species clusters were identified within the Hexacentrus japonicus clade. Based on the 99% sequence similarity obtained by blast search of the NCBI GenBank database, one of the clusters was identified as H. unicolor. Thus, the DNA barcoding revealed the presence of at least three cryptic species in Korean Tettigoniidae, although more detailed taxonomic analyses are required to establish their status. Therefore, we suggest that DNA barcoding is a very useful tool for increasing the identification accuracy of insect collections.     

Repellent efficacy of essential oils and plant extracts against Tribolium castaneum and Plodia interpunctella

This study was conducted to investigate the repellent efficacy of essential oils (Origanum vulgare, Pimpinella anisum, and Tanacetum cinerariifolium) and four plant extracts (Agastache rugosa, Capsicum annuum, Citrus reticulata, and Ginkgo biloba) against Tribolium castaneum (adults and larvae) and Plodia interpunctella (larvae). Gas chromatography/mass spectrometry analysis revealed the presence of carvacrol, anethole, and jasmolin I as the predominant constituent in O. vulgare, P. anisum, and T. cinerariifolium, respectively. Furthermore, ethyl hexopyranoside, 9,12‐octadecadienoic acid, cyclopentanol, and 2‐cresol were identified in A. rugosa, C. annuum, C. reticulata, and G. biloba, respectively. The repellent efficacy of each essential oil, plant extract, and the combination of oils was evaluated using a specially designed cylinder trap for 120 h. Among the three oils, O. vulgare and T. cinerariifolium had greatest repellent efficacy against P. interpunctella larvae. T. cinerariifolium exhibited effective repellence against the adults and larvae of T. castaneum. Therefore, O. vulgare (O) and T. cinerariifolium (T) were selected for further investigation of combined effects. Two essential oils were mixed in three different ratios of OT1 (1:3), OT2 (1:1), and OT3 (3:1). The repellent efficacies of OT1 and OT2 against the adults of T. castaneum were significantly greater than that of OT3. OT1 was effective against the larvae of T. castaneum, whereas OT2 was effective against the larvae of P. interpunctella. OT1 enhanced the repellent efficacy by approximately five times against larvae of T. castaneum, compared with that of T. cinerariifolium. Overall, OT1 was selected as the best repellent substance against all the tested insects.     

Insight into the bovine milk peptide LPcin‐YK3 selection in the proteolytic system of Lactobacillus species

Antimicrobial peptides are class of small, positively charged peptides known for their broad‐spectrum antimicrobial activity. Antimicrobial activities for most antimicrobial peptides have largely remained elusive, particularly in the lactic acid bacteria. However, recently our investigation using LPcin‐YK3, an antimicrobial peptide from bovine milk, suggests that in vitro antimicrobial activity was reduced over 100‐fold compared with pathogenic bacteria. Additionally, for the structural study of how antimicrobial peptide undergoes its reaction at the proteolytic pathway of lactic acid bacteria based on degradation assay and propidium iodide staining, we performed molecular docking for interaction between oligopeptide‐binding protein A and LPcin‐YK3 peptide. Given that degradation related to the LPcin‐YK3 peptide in lactic acid bacteria proteolytic system, the inhibitory inactivity of LPcin‐YK3 against beneficial lactic acid bacteria strains may be one of the primary pharmacological properties of recombinant peptide discovered in bovine milk. These results provide structural and functional insights into the proteolytic mechanism and possibility as a putative substrate of oligopeptide‐binding protein A in respect of LPcin‐YK3 peptide.     

Evolutionary processes of melanomas from giant congenital melanocytic nevi

Melanoma can develop in a congenital melanocytic nevus (CMN). In fact, a large CMN is associated with a high risk of developing melanoma. Although melanomas arising from CMNs are thought to have a pathogenesis distinct from conventional melanomas, no studies have been conducted on the evolution or tumor heterogeneity of CMN melanomas. We applied multi‐region whole‐exome sequencing to investigate the clonal nature of driver events and evolutionary processes in CMNs and melanomas arising from CMNs. In two patients, we observed an independent subclonal evolution in cancerized fields of CMNs and chromosome 8q amplification in both melanomas arising from CMNs. The amplification of MYC, located in chromosome 8q, was correlated with the percentage of tumor cells expressing high levels of MYC protein detected in melanoma cells by immunohistochemistry. Our analysis suggests that each CMN cell may evolve sporadically and that amplification of MYC might be a key event for melanoma development in CMNs.     

Arabidopsis RING E3 ubiquitin ligase JUL1 participates in ABA‐mediated microtubule depolymerization,stomatal closure,and tolerance response to drought stress

Ubiquitination is a critical post‐translational protein modification that has been implicated in diverse cellular processes, including abiotic stress responses, in plants. In the present study, we identified and characterized a T‐DNA insertion mutant in the At5g10650 locus. Compared to wild‐type Arabidopsis plants, at5g10650 progeny were hyposensitive to ABA at the germination stage. At5g10650 possessed a single C‐terminal C3HC4‐type Really Interesting New Gene (RING) motif, which was essential for ABA‐mediated germination and E3 ligase activity in vitro. At5g10650 was closely associated with microtubules and microtubule‐associated proteins in Arabidopsis and tobacco leaf cells. Localization of At5g10650 to the nucleus was frequently observed. Unexpectedly, At5g10650 was identified as JAV1‐ASSOCIATED UBIQUITIN LIGASE1 (JUL1), which was recently reported to participate in the jasmonate signaling pathway. The jul1 knockout plants exhibited impaired ABA‐promoted stomatal closure. In addition, stomatal closure could not be induced by hydrogen peroxide and calcium in jul1 plants. jul1 guard cells accumulated wild‐type levels of H₂O₂ after ABA treatment. These findings indicated that JUL1 acts downstream of H₂O₂ and calcium in the ABA‐mediated stomatal closure pathway. Typical radial arrays of microtubules were maintained in jul1 guard cells after exposure to ABA, H₂O₂, and calcium, which in turn resulted in ABA‐hyposensitive stomatal movements. Finally, jul1 plants were markedly more susceptible to drought stress than wild‐type plants. Overall, our results suggest that the Arabidopsis RING E3 ligase JUL1 plays a critical role in ABA‐mediated microtubule disorganization, stomatal closure, and tolerance to drought stress.     

Study of the independent gametophytes found on Jeju Island in South Korea and the first record of the obligate independent gametophyte of Antrophyum obovatum Baker

Fern gametophytes have often been neglected in research; however, studies on gametophytes are crucial for a better understanding of the evolution of ferns. During their life cycle, some gametophytes produce large and long‐lived populations without producing sporophytes and reproduce independently through asexual means, such as through the formation of gemmae. In this study, we investigated independent gametophytes on the Jeju Island of Korea, which was located on the land bridge between East China and Japan during the glacial periods. Fourteen gametophyte populations were collected from seven sites, of which 13 populations were clearly identified as belonging to four fern species known to occur in Jeju Island with BLAST searches using rbcL and trnL‐F sequences. Surprisingly, the last remaining population constituted undescribed taxa in Korea. We presented the first report of the independent gametophytes of Antrophyum obovatum Baker which has not been previously recorded in Korea. It has been supposed that many ferns sought suitable habitat throughout the land bridge between China and Japan. However, Jeju Island might be unsuitable for vittarioid ferns that prefer a tropical or subtropical environment. Consequently, only two species of vittariod ferns (A. obovatum and Haplopteris flexuosa (Fée) E.H. Crane) in the form of a gametophyte and sporophyte, respectively, exist on Jeju Island. Therefore, this gametophyte population must be protected and managed from a conservation perspective. In the case of the independent gametophyte of Hymenophyllum wrightii Bosch, haplotype analysis was conducted based on the rbcL sequences and the result supported that the North American populations were migrated from Japan through land bridge during the glacial periods and Jeju populations were recently established by long‐distance dispersal of the Japanese populations.     

Evolution of ecospace occupancy by Mesozoic marine tetrapods

Ecology and morphology are different, and yet in comparative studies of fossil vertebrates the two are often conflated. The macroevolution of Mesozoic marine tetrapods has been explored in terms of morphological disparity, but less commonly using ecological‐functional categories. Here we use ecospace modelling to quantify ecological disparity across all Mesozoic marine tetrapods. We document the explosive radiation of marine tetrapod groups in the Triassic and their rapid attainment of high ecological disparity. Late Triassic extinctions led to a marked decline in ecological disparity, and the recovery of ecospace and ecological disparity was sluggish in the Early Jurassic. High levels of ecological disparity were again achieved by the Late Jurassic and maintained during the Cretaceous, when the ecospace became saturated by the Late Cretaceous. Sauropterygians, turtles and ichthyosauromorphs were the largest contributors to ecological disparity. Throughout the Mesozoic, we find that established groups remained ecologically conservative and did not explore occupied or vacant niches. Several parts of the ecospace remained vacant for long spans of time. Newly evolved, radiating taxa almost exclusively explored unoccupied ecospace, suggesting that abiotic releases are needed to empty niches and initiate diversification. In the balance of evolutionary drivers in Mesozoic marine tetrapods, abiotic factors were key to initiating diversification events, but biotic factors dominated the subsequent generation of ecological diversity.