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Bisphenol A (BPA) is an endocrine-disrupting compound, and the binding mechanism of BPA with carrier proteins has drawn widespread attention. Halogen substitutions can significantly impact the properties of BPA, resulting in various effects for human health. Here, we selected tetrabromobisphenol A (TBBPA) and tetrachlorobisphenol A (TCBPA) to investigate the interaction between different halogen-substituted BPAs and human serum albumin (HSA). TBBPA/TCBPA spontaneously occupied site I and formed stable binary complexes with HSA. Compared to TCBPA, TBBPA has higher binding affinity to HSA. The effect of different halogen substituents on the negatively charged surface area of BPA was an important reason for the higher binding affinity of TBBPA to HSA compared to TCBPA. Hydrogen bonds and van der Waals forces were crucial in the TCBPA–HSA complex, while the main driving factor for the formation of the TBBPA–HSA complex was hydrophobic interactions. Moreover, the presence of TBBPA/TCBPA changed the secondary structure of HSA. Amino acid residues such as Lys199, Lys195, Phe211, Arg218, His242, Leu481, and Trp214 were found to play crucial roles in the binding process between BPA compounds and HSA. Furthermore, the presence of halogen substituents facilitated the binding of BPA compounds with HSA. [ABSTRACT FROM AUTHOR]

Simple Summary: The bark beetle is the most well-known pest in coniferous trees worldwide. These insects only leave the host pine bark when they disperse to locate a new host. Determining how Dendroctonus armandi overcome the trees' terpene-based defense systems has been the key problem in the study of bark beetles. Therefore, the aim of this study was to discover the molecular mechanism of insect detoxification enzymes' ability to confer resistance to terpenes. For this purpose, the genes of cytochrome P450s, glutathione S-transferases, and carboxylesterases were studied in beetles given diets containing terpenes. The results suggest that beetles express different genes in response to terpenoids, and the responses of multiple detoxifying enzymes indicate these insects' adaption to their chemical environment. Bark beetles overcome the toxic terpenoids produced by pine trees by both detoxifying and converting them into a pheromone system. Detoxification enzymes such as cytochrome P450s, glutathione S-transferases, and carboxylesterases are involved in the ability of Dendroctonus armandi to adapt to its chemical environment. Ten genes from these three major classes of detoxification enzymes were selected to study how these enzymes help D. armandi to respond to the host defenses. The expression profile of these detoxification enzyme genes was observed in adult beetles after feeding on different types of diet. Significant differences were observed between two types of seminatural diet containing the phloem of pines, and a purely artificial diet containing five monoterpenes ((−)-α-pinene, (−)-β-pinene, (+)-3-carene, (±)-limonene, and turpentine oil) also caused differential transcript levels in the detoxification enzyme genes. The results suggest that monoterpenes enter the beetles through different routes (i.e., respiratory and digestive systems) and cause the expression of different genes in response, which might be involved in pheromone metabolism. In addition, the xenobiotic metabolism in bark beetles should be considered as a system comprising multiple detoxifying enzymes. [ABSTRACT FROM AUTHOR]

In order to prevent any further spread of Dendroctonus armandi (Coleoptera: Curculionidae: Scolytidae), it is important to clarify its geographic distribution in China. Species Distribution Models were used to identify the variables influencing the distribution of D. armandi in China, and to create maps of its distribution. D. armandi almost exclusively attacked Pinus armandi Franch (IP (frequency of its incidence) = 98.2%), and its distribution is focused on the Qinling Mountains and the Ta-pa Mountains. The current distribution of P. armandi does not limit the distribution of D. armandi, despite the host occurring in in northern and southwestern China. Temperature and precipitation limit the current distribution of this beetle. The mean temperature of coldest quarter (−5 °C) does not guarantee that D. armandi larvae can overwinter in northern China, and the precipitation of wettest quarter plays an important role in the dispersal and colonization of D. armandi adults in southwestern China. Therefore, the ecological niche of this beetle is relatively narrow when it comes to these environmental variables. The climatic conditions where this beetle inhabit are different from the prevalent climate in the Qinling Mountains and the Ta-pa Mountains. At the meso- and micro-scale levels, terrain variables create habitat selection preferences for D. armandi. D. armandi predominately colonizes trees on the southern slopes of valleys and canyons with elevations between 1300 m a.s.l and 2400 m a.s.l. [ABSTRACT FROM AUTHOR]

We comprehensively investigated the biodiversity of fungal communities in different developmental stages of Trypophloeus klimeschi and the difference between sexes and two generations by high throughput sequencing. The predominant species found in the intestinal fungal communities mainly belong to the phyla Ascomycota and Basidiomycota. Fungal community structure varies with life stage. The genera Nakazawaea, Trichothecium, Aspergillus, Didymella, Villophora, and Auricularia are most prevalent in the larvae samples. Adults harbored high proportions of Graphium. The fungal community structures found in different sexes are similar. Fusarium is the most abundant genus and conserved in all development stages. Gut fungal communities showed notable variation in relative abundance during the overwintering stage. Fusarium and Nectriaceae were significantly increased in overwintering mature larvae. The data indicates that Fusarium might play important roles in the survival of T. klimeschi especially in the overwintering stage. The authors speculated that Graphium plays an important role in the invasion and colonization of T. klimeschi. The study will contribute to the understanding of the biological role of the intestinal fungi in T. klimeschi, which might provide an opportunity and theoretical basis to promote integrated pest management (IPM) of T. klimeschi. [ABSTRACT FROM AUTHOR]

Leptographium qinlingensis is a fungal associate of the Chinese white pine beetle (Dendroctonus armandi) and a pathogen of the Chinese white pine (Pinus armandi) that must overcome the terpenoid oleoresin defenses of host trees. L. qinlingensis responds to monoterpene flow with abundant mechanisms that include export and the use of these compounds as a carbon source. As one of the fungal cytochrome P450 proteins (CYPs), which play important roles in general metabolism, CYP51 (lanosterol 14-α demethylase) can catalyze the biosynthesis of ergosterol and is a target for antifungal drug. We have identified an L. qinlingensis CYP51F1 gene, and the phylogenetic analysis shows the highest homology with the 14-α-demethylase sequence from Grosmannia clavigera (a fungal associate of Dendroctonus ponderosae). The transcription level of CYP51F1 following treatment with terpenes and pine phloem extracts was upregulated, while using monoterpenes as the only carbon source led to the downregulation of CYP5F1 expression. The homology modeling structure of CYP51F1 is similar to the structure of the lanosterol 14-α demethylase protein of Saccharomyces cerevisiae YJM789, which has an N-terminal membrane helix 1 (MH1) and transmembrane helix 1 (TMH1). The minimal inhibitory concentrations (MIC) of terpenoid and azole fungicides (itraconazole (ITC)) and the docking of terpenoid molecules, lanosterol and ITC in the protein structure suggested that CYP51F1 may be inhibited by terpenoid molecules by competitive binding with azole fungicides.