Effects of octylphenol exposure on the lipid metabolism and microbiome of the intestinal tract of Rana chensinensis tadpole by RNAseq and 16s amplicon sequencing

Gut microbiota perturbations during larval stages in Bufo gargarizans tadpoles after Cu exposure with or without the presence of Pb

Cu and Pb are ubiquitous environmental contaminants, but there is limited information on their potential impacts on gut microbiota profile in anuran amphibians at different developmental stages during metamorphosis. In this study, Bufo gargarizans tadpoles were chronically exposed to Cu alone or Cu combined with Pb from Gs26 throughout metamorphosis. Morphology of tadpoles, histological characteristic and bacterial community of intestines were evaluated at three developmental stages: Gs33, Gs36, and Gs42. Results showed that Cu and Cu + Pb exposure caused various degrees of morphological and histological changes in guts at tested three stages. In addition, bacterial richness and diversity in tadpoles especially at Gs33 and Gs42 were disturbed by Cu and Cu + Pb. Beta diversity demonstrated that the bacterial community structures were influenced by both heavy metals exposure and developmental stages. Alterations in taxonomic composition were characterized by increased abundance of Proteobacteria and Firmicutes, reduction of Fusobacteriota, as well as decreased Cetobacterium and increased C39 at all three stages. Overall, response of gut bacterial diversity and composition to Cu stress depends on the developmental stage, while the altered patterns of bacterial community at Cu stress could be modified further by the presence of Pb. Moreover, predicted metabolic disorders were associated with shifts in bacterial community, but needs integrated information from metagenomic and metatranscriptomic analyses. These results contribute to the growing body of research about potential ecotoxicological effects of heavy metals on amphibian gut microbiota during metamorphosis.

Effects of perchlorate and exogenous T4 on growth, development and tail resorption of Rana chensinensis

Endocrine disruptors have been demonstrated to exert adverse effects on growth and development of amphibians by disrupting hormone levels. Tail resorption, which is one of the most remarkable events during amphibian metamorphosis, is closely associated with thyroid hormones levels. However, limited research has been conducted on the effects of endocrine disruptors on tail resorption in amphibians. This study explored the effects of NaClO4 and T4 on the growth, development and tail resorption during the metamorphosis of Rana Chensinensis. The results demonstrated that exposure to NaClO4 led to an increase in body size and a delay in metamorphosis of R. Chensinensis tadpoles. Histological analysis revealed that both NaClO4 and exogenous T4 exposure resulted in thyroid gland injury, and NaClO4 treatment delayed the degradation of notochord and muscles, thereby delaying tail resorption. Moreover, transcriptome sequencing results showed that apoptosis-related genes (APAF1, BAX and CASP6) and cell component degradation-related genes (MMP9 and MMP13) were highly expressed in the T4 exposure group, and the expression of oxidative stress-related genes (SOD and CAT) was higher in the NaClO4 exposure group. Taken together, both NaClO4 and exogenous T4 affect tail resorption in R. Chensinensis, thereby affecting their adaptation to terrestrial life. The present study will not only provide a reference for future experimental research on the effects of other endocrine disruptors on the growth, development and tail resorption of amphibians but will also provide insights into environmental protection and ecological risk assessment.

The Association between 4-Tertiary-Octylphenol, Apoptotic Microparticles, and Carotid Intima-Media Thickness in a Young Taiwanese Population

As one of the most common alkylphenols, 4-tertiary-octylphenol (4-tOP) is commonly used in many consumer products. Our previous epidemiological study revealed a negative correlation between serum 4-tOP levels and carotid intima-media thickness (CIMT), which serves as a biomarker of arteriosclerosis. We aimed to explore the role of apoptotic microparticles, markers of vascular endothelial cell function, in the 4-tOP and CIMT connection. To investigate this, we enrolled 886 Taiwanese adolescents and young adults (aged 12-30 years) and examined the relationships among serum 4-tOP levels, apoptotic microparticles (CD31+/CD42a-, CD31+/CD42a+), and CIMT. Our results showed negative associations among serum 4-tOP levels, both apoptotic microparticles, and CIMT in multiple linear regression analysis. The odds ratios for CIMT (≥75th percentile) and the natural logarithm of 4-tOP were highest when both CD31+/CD42a- and CD31+/CD42a+ were greater than the 50th percentile. Conversely, the odds ratios were lowest when both CD31+/CD42a- and CD31+/CD42a+ were less than the 50th percentile. In the structural equation model, we demonstrated that serum 4-tOP levels were negatively correlated with CIMT and indirectly and negatively correlated with CIMT through both apoptotic microparticles. In conclusion, our study reported the inverse association between 4-tOP apoptotic microparticles and CIMT in a young Taiwanese population. Further experimental studies are needed to clarify these associations.

Exposure to Roundup and Antibiotics Alters Gut Microbial Communities, Growth, and Behavior in Rana berlandieri Tadpoles

The gut microbiome is important for digestion, host fitness, and defense against pathogens, which provides a tool for host health assessment. Amphibians and their microbiomes are highly susceptible to pollutants including antibiotics. We explored the role of an unmanipulated gut microbiome on tadpole fitness and phenotype by comparing tadpoles of Rana berlandieri in a control group (1) with tadpoles exposed to: (2) Roundup® (glyphosate active ingredient), (3) antibiotic cocktail (enrofloxacin, sulfamethazine, trimethoprim, streptomycin, and penicillin), and (4) a combination of Roundup and antibiotics. Tadpoles in the antibiotic and combination treatments had the smallest dorsal body area and were the least active compared to control and Roundup-exposed tadpoles, which were less active than control tadpoles. The gut microbial community significantly changed across treatments at the alpha, beta, and core bacterial levels. However, we did not find significant differences between the antibiotic- and combination-exposed tadpoles, suggesting that antibiotic alone was enough to suppress growth, change behavior, and alter the gut microbiome composition. Here, we demonstrate that the gut microbial communities of tadpoles are sensitive to environmental pollutants, namely Roundup and antibiotics, which may have consequences for host phenotype and fitness via altered behavior and growth.

Gut microbial response to host metabolic phenotypes

A large number of studies have proved that biological metabolic phenotypes exist objectively and are gradually recognized by humans. Gut microbes affect the host's metabolic phenotype. They directly or indirectly participate in host metabolism, physiology and immunity through changes in population structure, metabolite differences, signal transduction and gene expression. Obtaining comprehensive information and specific identification factors associated with gut microbiota and host metabolic phenotypes has become the focus of research in the field of gut microbes, and it has become possible to find new and effective ways to prevent or treat host metabolic diseases. In the future, precise treatment of gut microbes will become one of the new therapeutic strategies. This article reviews the content of gut microbes and carbohydrate, amino acid, lipid and nucleic acid metabolic phenotypes, including metabolic intermediates, mechanisms of action, latest research findings and treatment strategies, which will help to understand the relationship between gut microbes and host metabolic phenotypes and the current research status.

Morphology and molecular mechanisms of tail resorption during metamorphosis in Rana chensinensis tadpole (Anura: Ranidae)

The tail resorption process was an inevitable and pivotal transformation during amphibian metamorphosis. The present study investigated the mechanisms of tail resorption through histological and transcriptome analysis in Rana chensinensis. The results showed that tail resorption was initiated before the onset of metamorphic climax, and dramatically regressed after metamorphic climax by external-morphology measurement. The drastic disintegration of tail muscle and notochord occurred at Gs42-44, which were consistent with the trend of thyroid follicular cell height. Besides, expression level analysis and functional annotation of DEGs (differentially expressed genes) were conducted through RNA-seq analysis of the tail. Our study also analyzed the expression of genes related to oxidative stress, autophagy, apoptosis and degradation of cellular components in the tail of R. chensinensis. This study enriched the R. chensinensis transcriptome database and laid the foundation of further analysis of tail resorption.

Effects of Mixing Garlic Skin on Fermentation Quality, Microbial Community of High-Moisture Pennisetum hydridum Silage

Garlic skin, a by-product of garlic processing, was supposed to improve the fermentation quality of high-moisture silages because of its low moisture content and active compounds. Thus, fermentation and microbial characteristics of high-moisture Pennisetum hydridum ensiled with the addition of 0, 10, 20, and 30 wt% garlic skin (on a fresh matter basis) were analyzed during a 60-days fermentation. Results showed that the addition of garlic skin increased the dry matter content and lactic acid production, and decreased the pH and ammonia-N content of the silage. Adding garlic skin changed the relative abundance of bacterial communities with an increase in Lactobacillus and a decrease in Clostridium relative abundance. In conclusion, co-ensiling of high-moisture Pennisetum hydridum with garlic skin could be a simple approach to improve the silage quality and nutrients preservation.

Xenoestrogen Effects on the Gut Microbiome

Endocrine disrupting chemicals (EDCs) that act as xenoestrogens are natural and synthetic chemicals widely present in food products, industrial products, and the environment. Such compounds can activate or inhibit normal hormonal pathways by binding to steroid and non-steroid receptors. It is becomingly apparent that resident bacteria in the gut and elsewhere in the body can dramatically influence host responses. As such, increasing number of studies have examined how EDCs affect the gut microbiome in a range of animal species. This review article will examine what is known about how various xenoestrogens, including bisphenol A (BPA), phthalates, and phytoestrogens, affect the gut microbiome in vertebrate species, any known secondary host effects, such as through alteration of gut metabolites, and future directions in the field.

Binding mechanism of 4-octylphenol with human serum albumin: Spectroscopic investigations, molecular docking and dynamics simulation

4-Octylphenol (OP) is an environmental estrogen that can enter organisms through the food chain and cause various toxic effects. Here, the interaction between OP and human serum albumin (HSA) was explored through multipectral, molecular docking and dynamics simulation. The results showed that OP and HSA formed a ground state complex through a static quenching mechanism, and the interaction was spontaneously driven by hydrogen bonds and hydrophobic interaction forces. The binding constant at different temperatures was measured to be on the order of 10⁵ L mol^-1. Site competition experiments suggested that OP interacted with amino acid residues Lys195, Cy245 and Cys246 located at the Sudlow site I of HSA, resulting in a more stretched protein peptide. The presence of OP increased the surface hydrophobicity of HSA, and reduced the content of α-helix in HSA by 3.4%. FT-IR spectra showed that OP interacted with the C=O and C-H groups of the polypeptide backbone. Molecular docking demonstrated that OP mainly bound to Site I of HSA and hydrogen bonds participated in the interaction. In addition, molecular dynamics simulations further explored the stability and dynamic behavior of the OP-HSA complex through RMSD, RMSF, SASA and Rg.

Seasonal Variation in Gut Microbiota Related to Diet in Fejervarya limnocharis

Organisms adapt to environmental fluctuations by varying their morphology and structural, physiological, and biochemical characteristics. Gut microbiome, varying rapidly in response to environmental shifts, has been proposed as a strategy for adapting to the fluctuating environment (e.g., new dietary niches). Here, we explored the adaptive mechanism of frog intestinal microbes in response to environmental changes. We collected 170 Fejervarya limnocharis during different seasons (spring, summer, autumn, and pre-hibernation) to study the compositional and functional divergence of gut microbiota and analysed the effects of seasonal feeding habits and body condition on intestinal microorganisms using 16S rRNA high-throughput sequencing, Tax4Fun function prediction analysis, and bioinformatics analysis. The results showed no significant dietary difference in various seasons and between males and females. However, a significantly positive correlation was detected between dietary diversity and food niche width. Host condition (body size, body mass, and body condition) also revealed seasonal changes. The frogs were colonised by 71 bacterial phyla and dominated by Proteobacteria, Firmicutes, and Bacteroidetes. Stenotrophomonas was the most abundant genus in the Proteobacteria. The composition, diversity, and function of intestinal microorganisms in different seasons were significantly different. Significant differences were observed in composition and function but not in the microbial diversity between sexes. Furthermore, seasonal foods and body mass were significantly correlated with gut microbial composition. Our results suggest that gut microbiomes of F. limnocharis vary seasonally in response to diet under fluctuating environments.