Breakdown Of Fibers Research Articles

Rhabdomyolysis secondary to COVID-19 infection and vaccination: a review of literature.

Rhabdomyolysis (RML), characterized by the breakdown of skeletal muscle fibers and the release of muscle contents into the bloodstream, has emerged as a notable complication associated with Coronavirus disease 2019 (COVID-19) infection and vaccination. Studies have reported an increased incidence of RML in individuals with severe COVID-19 infection. However, the exact mechanisms remain unclear and are believed to involve the host's immune response to the virus. Furthermore, RML has been documented as a rare adverse event following COVID-19 vaccination, particularly with mRNA vaccines. Proposed mechanisms include immune responses triggered by the vaccine and T-cell activation against viral spike proteins. This study aims to review the current literature on the incidence, pathophysiology, clinical presentation, and outcomes of RML secondary to COVID-19 infection and vaccination. We identify common risk factors and mechanisms underlying this condition by analyzing case reports, clinical studies, and pharmacovigilance data. Our findings suggest that while RML is a relatively rare adverse event, it warrants attention due to its potential severity and the widespread prevalence of COVID-19 and its vaccines. This review underscores the need for heightened clinical awareness and further research to optimize management strategies and improve patient outcomes in this context.

Sustainable innovations and future prospects in construction material: a review on natural fiber-reinforced cement composites.

There is a growing trend in the construction industry to adopt environmentally friendly practices, and innovative materials are becoming increasingly popular. Within the scope of this paper, the potential of natural fiber-reinforced cement composites (NFRCs) as an environmentally friendly building material is examined. This work introduces plant fiber aspects such as micromorphology, primary components, physical and mechanical properties, chemical components, thermal properties, and degradation mechanisms in cement composites. It explores how plant fibers affect concrete's mechanical performance, durability, and thermal qualities. It is responsible for increasing permeability and decreasing durability in concrete material because plant fibers have porosity and a weak interface. The purpose of this in-depth investigation is to investigate the features, sustainability (social, environmental, and economical) performance, and applications of NFRCs, with a particular focus on environmentally responsible innovation and potential future applications. The exhaustive study also addresses the difficulties associated with attaining the highest possible level of compatibility between fibers and matrixes. The physical and chemical treatments of natural fibers in cement components give more resistance to aging by reducing water absorption and increasing roughness at the surface. It is also possible to reduce the effect of alkalinity of the cement mixture through optimization of the binder component and curing regimes, which retard the breakdown of natural fibers. The purpose of this study is to present a summary of existing research, with a particular emphasis on the benefits, drawbacks, and prospective ways in which NFRCs could potentially improve throughout the construction industry in the future.

Effects of Prebiotic Dietary Fibers on the Stimulation of the Mucin Secretion in Host Cells by In Vitro Gut Microbiome Consortia.

The gastrointestinal microbiota are important for human health. Dietary intake may modulate the composition and metabolic function of the gut microbiome. We examined how the breakdown of prebiotic dietary fibers by the gut microbiome affects mucin secretion by intestinal epithelial cells. Metagenomic analyses of in vitro gut microbiome consortia revealed taxonomic profiles and genetic diversity of carbohydrate-active enzymes that digest polysaccharides. Two independent consortia exhibited different abilities to produce acetic acid, propionic acid, and butyric acid via the fermentation of polysaccharides derived from dietary fibers of grains and mushrooms. Although acetic acid generally had the highest concentration, the ratios of butyric acid and propionic acid to acetic acid varied depending on the polysaccharide source. These short-chain fatty acids affected morphological differentiation and mucin secretion in HT-29 human intestinal epithelial cells. These results suggest that prebiotic dietary fibers can be digested and metabolized by the gut microbiome to short-chain fatty acids, which can affect gut epithelial cells both directly and indirectly via the modulation of the gut microbiota and their enzymes.

Fiber Alignment's Effect on the Properties of Hybrid Glass/Flax Fiber‐Reinforced Epoxy Composite Laminates

ABSTRACTIn this study, glass fiber and flax fiber reinforced with epoxy and ZnO nanofiller were used to create composites utilizing the hand layup method. The purpose of this study is to develop a novel hybrid polymer‐matrix composite that can be employed in various application areas such as aerospace, sports, medical equipment, railways, etc. The fabricated composite was made with epoxy as a matrix material reinforced with nano‐ZnO, glass fiber, and flax fiber. Six fiber layers with varying fiber orientations were inserted into the matrix in a specific stacking order. The results show the maximum tensile, flexural, impact, and ILSS as the values of 264.74 MPa, 492.12 MPa, 595.72 J/m, and 50.05, respectively. Along with the mechanical properties, Physical characterization such as density, void content, thickness swelling, moisture content, and water absorption tests were conducted. FE‐SEM test was conducted to check the uniformity of nanoparticles in the matrix material and the breakdown of fibers.

Adding rumen microorganisms to improve fermentation quality, enzymatic efficiency, and microbial communities of hybrid Pennisetum silage

Hybrid Pennisetum, a top biomass energy source, faces usage limitations because of its scarce lactic acid bacteria and high fiber content. This study assessed the influence of rumen fluid pretreatment on hybrid Pennisetum’s silage, with focus on silage duration and rumen fluid effects on quality and fiber decomposition. Advanced third-generation sequencing was used to track microbial diversity changes and revealed that rumen fluid considerably enhanced dry matter, crude protein, and water-soluble carbohydrates, thus improving fermentation quality to satisfactory pH levels (3.40–3.67). Ideal results, including the highest fiber breakdown and enzymatic efficiency (47.23 %), were obtained with 5 % rumen fluid in 60 days. The addition of rumen fluid changed the dominant species, including Paucilactobacillus vaccinostercus (0.00 % vs. 18.21 %) and Lactiplantibacillus plantarum (21.03 % vs. 47.02 %), and no Enterobacter was detected in the high-concentration treatments. Moreover, strong correlations were found between specific lactic acid bacteria and fermentation indicators, revealing the potential of achieving efficient and economically beneficial hybrid Pennisetum production.

The Postbiotic Properties of Butyrate in the Modulation of the Gut Microbiota: The Potential of Its Combination with Polyphenols and Dietary Fibers.

The gut microbiota is a diverse bacterial community consisting of approximately 2000 species, predominantly from five phyla: Firmicutes, Bacteroidetes, Actinobacteria, Proteobacteria, and Verrucomicrobia. The microbiota's bacterial species create distinct compounds that impact the host's health, including well-known short-chain fatty acids. These are produced through the breakdown of dietary fibers and fermentation of undigested carbohydrates by the intestinal microbiota. The main short-chain fatty acids consist of acetate, propionate, and butyrate. The concentration of butyrate in mammalian intestines varies depending on the diet. Its main functions are use as an energy source, cell differentiation, reduction in the inflammatory process in the intestine, and defense against oxidative stress. It also plays an epigenetic role in histone deacetylases, thus helping to reduce the risk of colon cancer. Finally, butyrate affects the gut-brain axis by crossing the brain-blood barrier, making it crucial to determine the right concentrations for both local and peripheral effects. In recent years, there has been a significant amount of attention given to the role of dietary polyphenols and fibers in promoting human health. Polyphenols and dietary fibers both play crucial roles in protecting human health and can produce butyrate through gut microbiota fermentation. This paper aims to summarize information on the key summits related to the negative correlation between intestinal microbiota diversity and chronic diseases to guide future research on determining the specific activity of butyrate from polyphenols and dietary fibers that can carry out these vital functions.

A mechanistic modelling approach of the host-microbiota interactions to investigate beneficial symbiotic resilience in the human gut.

The health and well-being of a host are deeply influenced by the interactions with its gut microbiota. Contrasted environmental conditions, such as diseases or dietary habits, play a pivotal role in modulating these interactions, impacting microbiota composition and functionality. Such conditions can also lead to transitions from beneficial to detrimental symbiosis, viewed as alternative stable states of the host-microbiota dialogue. This article introduces a novel mathematical model exploring host-microbiota interactions, integrating dynamics of the colonic epithelial crypt, microbial metabolic functions, inflammation sensitivity and colon flows in a transverse section. The model considers metabolic shifts in epithelial cells based on butyrate and hydrogen sulfide concentrations, innate immune pattern recognition receptor activation, microbial oxygen tolerance and the impact of antimicrobial peptides on the microbiota. Using the model, we demonstrated that a high-protein, low-fibre diet exacerbates detrimental interactions and compromises beneficial symbiotic resilience, underscoring a destabilizing effect towards an unhealthy state. Moreover, the proposed model provides essential insights into oxygen levels, fibre and protein breakdown, and basic mechanisms of innate immunity in the colon and offers a crucial understanding of factors influencing the colon environment.

PSI-17 Effect of timing of high dietary zinc supplementation on the microbiome of gestating sows and their piglets

Abstract The objective of this study was to assess if high dietary zinc (Zn) fed to gestating sows modulates the microbiome of the sow and that of their offspring. Sows were fed 1 of 3 dietary treatments: 1) Control: a corn-soybean meal-based diet containing 125 ppm total supplemental zinc, 2) Breed-to-Farrow: as Control + 141 ppm supplemental Zn as ZnSO4 fed from 5 d post-breeding to farrowing; and 3) Day 110-to-Farrow: as Control + 2,715 ppm supplemental Zn as ZnSO4 starting on d 110 of gestation until farrowing. A subset of third parity sows (n = 30; 10 per treatment) were selected to assess the microbiome of colostrum, milk, and rectal and vaginal surfaces of sows. At farrowing, 4 pigs per litter (n = 120) were selected based on birthweight (BiW; 2 average BiW pigs and 2 pigs with BiW below the litter average) were selected to assess the piglet gut microbiome on the day of birth (d 0) and d5 of age. 16S rRNA sequencing was implemented for colostrum and milk samples while all other sample types were sequenced using shotgun metagenomics to determine taxonomic and functional profiles. Measures of alpha and beta diversity were conducted along with determination of differentially abundant taxa and pathways in tandem with generalized linear mixed models. Greater dietary concentrations of Zn fed to gestating sows minimally affected their colostrum, milk, and vaginal microbiome. However, fecal samples of Breed-to-Farrow sows showed decreased abundance of potentially pathogenic bacteria such as Salmonella enterica and Shigella flexneri and greater abundance of bacteria typically involved in fiber fermentation compared with Control sows (Figure 1a). Piglets born to Day 110-to-Farrow sows also showed greater abundance of some taxa typically involved in fiber breakdown and short chain fatty acid (SCFA) generation on d 5 compared with Control pigs (Figure 1b). At d 0, Breed-to-Farrow piglets showed less abundance of methanogenic archaea and differential abundance of taxa with potentially pathogenic roles, compared with Control pigs (Figure 1c). Gene families and pathways playing roles in central metabolic functions (starch, pyruvate, sucrose, amino acid metabolism) were more abundant in Breed-to-Farrow piglets compared with pigs born to Control sows on d 0 and 5 of age. In conclusion, greater Zn fed to gestating sows impacted the abundance of gut taxa with potential roles in SCFA-production and pathogenicity in both sow and piglet, despite overall minor effects. However, the physiological significance of these findings for the sow and piglet remains unclear.

Resident gut microbiota community determines the efficacy of soluble fiber in reducing adiposity.

Consumption of dietary fiber has been linked to several health benefits. Among these, dietary fiber breakdown through the process of anaerobic fermentation by the colonic microbiota leads to the production of beneficial metabolites, mainly short-chain fatty acids (acetate, propionate, and butyrate), which have been implicated in reduced calorie intake. Nevertheless, the link between gut microbiota and obesity remains unclear. We investigated the effects of dietary fibers on food intake and body weight gain in two independent but similarly designed studies in rats. In the first study, the inclusion of 10% w/w pectin, fructooligosaccharides or beta-glucan (n = 10/group) in the diets each significantly reduced body weight gain ('responders') compared to the cellulose control whereas, in a closely matched, but not fully identical study (n = 8/group), no effect of dietary fiber on body weight ('non-responders') was observed. The aim of this work was to explore the basis of this differential response between the two similarly designed and comparable studies, with a focus on the potential role of the gut microbiota in the control of food intake and body weight.

Bioplastic films from cassava peels: Enzymatic transformation and film properties

Annually, millions of tons of cassava peels are generated as agro-waste. This research repurposed entire cassava peels into biodegradable films as a sustainable alternative to single-use plastics. Enzymes (cellulase, xylanase, and glucanase) were employed to catalyze the process, and cassava peels were effectively converted into films, which exhibited comparable or even better mechanical properties and water resistance to commercial packaging materials. The films also presented high water solubility of 44–50% and good light barrier properties, with 15–23% transmittance values for visible light and less than 3% for UV light. Extended enzymatic treatment time resulted in films characterized by increased elasticity, solubility, water resistance, transparency, and smoother surfaces, which can be attributed to the enzymatic breakdown of cassava peel fibers into smaller saccharide units. The optimal enzymatic treatment time was found to be 4 h which produced films with favorable mechanical characteristics, barrier properties, and solubility. A sustainable and ecologically-friendly approach is provided to fully harness cassava peels in fabricating packaging films, particularly suited for food items necessitating dissolution in water.

Cardiovascular disease in Alpha 1 antitrypsin deficiency: an observational study assessing the role of neutrophil proteinase activity and the suitability of validated screening tools

BackgroundAlpha 1 Antitrypsin Deficiency (AATD) is a rare, inherited lung disease which shares features with Chronic Obstructive Pulmonary Disease (COPD) but has a greater burden of proteinase related tissue damage. These proteinases are associated with cardiovascular disease (CVD) in the general population. It is unclear whether patients with AATD have a greater risk of CVD compared to usual COPD, how best to screen for this, and whether neutrophil proteinases are implicated in AATD-associated CVD. This study had three aims. To compare CVD risk in never-augmented AATD patients to non-AATD COPD and healthy controls (HC). To assess relationships between CVD risk and lung physiology. To determine if neutrophil proteinase activity was associated with CVD risk in AATD. Cardiovascular risk was assessed by QRISK2® score and aortic stiffness measurements using carotid-femoral (aortic) pulse wave velocity (aPWV). Medical history, computed tomography scans and post-bronchodilator lung function parameters were reviewed. Systemic proteinase 3 activity was measured. Patients were followed for 4 years, to assess CVD development.Results228 patients with AATD, 50 with non-AATD COPD and 51 healthy controls were recruited. In all COPD and HC participants, QRISK2® and aPWV gave concordant results (with both measures either high or in the normal range). This was not the case in AATD. Once aPWV was adjusted for age and smoking history, aPWV was highest and QRISK2® lowest in AATD patients compared to the COPD or HC participants. Higher aPWV was associated with impairments in lung physiology, the presence of emphysema on CT scan and proteinase 3 activity following adjustment for age, smoking status and traditional CVD risk factors (using QRISK2® scores) in AATD. There were no such relationships with QRISK2® in AATD. AATD patients with confirmed CVD at four-year follow up had a higher aPWV but not QRISK2® at baseline assessment.ConclusionaPWV measured CVD risk is elevated in AATD. This risk is not captured by QRISK2®. There is a relationship between aPWV, lung disease and proteinase-3 activity. Proteinase-driven breakdown of elastin fibres in large arteries and lungs is a putative mechanism and forms a potential therapeutic target for CVD in AATD.

Bioavailability and health effects of some carotenoids by different cooking methods

Humans lack the inherent capability to synthesize carotenoids, necessitating their acquisition through dietary sources or supplementation. Among the carotenoids prevalent in our daily nutritional intake are beta-carotene, lycopene, lutein, beta-cryptoxanthin, alpha-carotene, and zeaxanthin. They have antioxidant features thanks to their ability to capture ROS (reactive oxygen species) and free radicals. Particularly beta-carotene, lycopene and lutein are carotenoids with high antioxidant capacity. However, with the effects of factors, such as oxygen, high temperature, light exposure, and pH, they are oxidatively degraded and their bioavailability in the body changes. Among food processing methods, reducing food size and dietary fiber inhibits the absorption of carotenoids by micellization and inactivating pancreatic lipase, while monounsaturated fatty acids have been shown to increase bioavailability and absorption. In vitro studies on various vegetables and fruits with the effect of exogenous factors showed that the addition of oil, increase in lycopene processing, decrease in food particle size, increase in micellization with the breakdown of dietary fibers, and increase in bioavailability as a result of the destruction of cell walls with heat treatment. The addition of olive oil with heat treatment and the factors of decreasing food particle size have positive effects on health by transforming carotenoids into forms with high bioavailability in the body. This review endeavors to investigate the bioavailability of select carotenoids, namely lycopene, beta-carotene, and lutein, in light of various cooking methods and processes, as well as to elucidate their implications for health resulting from heat treatments.

Cysteine and glycine-rich protein 3 (Crp3) as a critical regulator of elastolysis, inflammation, and smooth muscle cell apoptosis in abdominal aortic aneurysm development.

Abdominal aortic aneurysm (AAA) is a life-threatening vascular disease for which surgical or endovascular repair are the only currently available therapeutic strategies. The development of AAA involves the breakdown of elastic fibers (elastolysis), infiltration of inflammatory cells, and apoptosis of smooth muscle cells (SMCs). However, the specific regulators governing these responses remain unknown. We previously demonstrated that Cysteine and glycine-rich protein 3 (Crp3) sensitizes SMCs to apoptosis induced by stretching. Building upon this finding, we aimed to investigate the influence of Crp3 on elastolysis and apoptosis during AAA development. Using the elastase-CaCl2 rat model, we observed an increase in Crp3 expression, aortic diameter, and a reduction in wall thickness in wild type rats. In contrast, Crp3-/- rats exhibited a decreased incidence of AAA, with minimal or no changes in aortic diameter and thickness. Histopathological analysis revealed the absence of SMC apoptosis and degradation of elastic fibers in Crp3-/- rats, accompanied by reduced inflammation and diminished proteolytic capacity in Crp3-/- SMCs and bone marrow-derived macrophages. Collectively, our findings provide evidence that Crp3 plays a crucial role in AAA development by modulating elastolysis, inflammation, and SMC apoptosis. These results underscore the potential significance of Crp3 in the context of AAA progression and offer new insights into therapeutic targets for this disease.

Case Study of Pneumothorax in a 27-year-old Male as a Possible Post- COVID 19 Infection Complication

Spontaneous Pneumothorax is a potentially life-threatening condition that is brought on when air makes its way into the pleural spaces resulting in decreased negative pressure between the pleural membranes without trauma or injury occurring. Spontaneous pneumothorax was reported as an adverse complication of severe acute respiratory syndrome brought on by SARS-COV-2. It is thought spontaneous pneumothorax may be a consequence of the breakdown of elastic fibers within the lung tissue. This breakdown is believed to be caused by the body’s own immune response in particular by innate lymphoid cells (ILCs) which have been shown to be elevated in response to intracellular pathogens like viruses, but additional research is needed to clearly state a causal relationship between SARS-CoV-2 and the immune-mediated formation of pneumothorax. Limited studies look at the link between the pathophysiology of Pneumothorax and COVID-19, which is why the patient from this case is of interest. We present a unique case of a 27-year-old male presenting to the Emergency Department complaining of difficulty breathing, chest pain, and fatigue who had prior tested positive for COVID-19. A diagnosis of pneumothorax was made by chest x-ray. In this report, we discuss the pathophysiology, imaging, and management related to pneumothorax and its connection to COVID-19.

Assessing Efficacy of Afatinib toward Elastic Matrix Repair in Aortic Aneurysms.

Abdominal aortic aneurysm (AAA) is a critical, multifactorial cardiovascular disorder marked by localized dilatation of the abdominal aorta. A major challenge to countering the pathophysiology of AAAs lies in the naturally irreversible breakdown of elastic fibers in the aorta wall, which is linked to the poor elastogenicity of adult and diseased vascular smooth muscle cells (SMCs) and their impaired ability to assemble mature elastic fibers in a chronic proteolytic tissue milieu. We have previously shown that these are downstream effects of neutrophil elastase-induced activation of the epidermal growth factor receptor (EGFR) activity in aneurysmal SMCs. The novelty of this study lies in investigating the benefits of an EGFR inhibitor drug, afatinib (used to treat nonsmall cell lung cancer), for proelastogenic and antiproteolytic stimulation of aneurysmal SMCs. In in vitro cell cultures, we have shown that safe doses of 0.5 and 1 nM afatinib inhibit EGFR and p-extracellular signal-regulated kinases 1/2 protein expression by 50-70% and downstream elastolytic matrix metalloprotease 2 (MMP2) versus untreated control cultures. In addition, elastin production on a per cell basis was significantly upregulated by afatinib doses within the 0.1-1 nM dose range, which was further validated through transmission electron microscopy showing significantly increased presence of tropoelastin coacervates and maturing elastic fibers upon afatinib treatment at the above doses. Therefore, our studies for the first time demonstrate the therapeutic benefits of afatinib toward use for elastic matrix repair in small AAAs.

Rhabdomyolysis aggravates renal iron accumulation and acute kidney injury in a humanized mouse model of sickle cell disease

Individuals with sickle cell disease (SCD) are at greater risk of rhabdomyolysis, a potentially life-threatening condition resulting from the breakdown of skeletal muscle fibers. Acute kidney injury (AKI) is one of the most severe complications of rhabdomyolysis. Chronic kidney and cardiovascular disease, which account for SCD mortality, are long-term consequences of AKI. Although SCD elevates the risks of rhabdomyolysis-induced sudden death, the mechanisms that underlie rhabdomyolysis-induced AKI in SCD are unclear. In the present study, we show that, unlike their control non-sickling (AA) counterparts, transgenic homozygous SCD (SS; Townes model) mice exhibited 100% mortality 8–24 h after intramuscular glycerol injection. Five hours after glycerol injection, SS mice showed a more significant increase in myoglobinuria and plasma creatine kinase levels than AA mice. Basal plasma heme and kidney tissue iron levels were significantly higher in SS than in AA mice. In contrast to AA, glycerol-induced rhabdomyolysis aggravated these parameters in SS mice. Rhabdomyolysis also amplified oxidative stress in SS compared to AA mice. Glycerol-treated SS mice exhibited worse renal function, exemplified by a reduction in GFR with a corresponding increase in plasma and urinary biomarkers of early AKI and renal tubular damage. The free radical scavenger and Fenton chemistry inhibitor, TEMPOL, ameliorated rhabdomyolysis-induced AKI in the SS mice. These findings demonstrate that oxidative stress driven by renal iron accumulation amplifies rhabdomyolysis-induced AKI in SCD mice.

Crystal Structures of Bacterial Pectin Methylesterases Pme8A and PmeC2 from Rumen Butyrivibrio.

Pectin is a complex polysaccharide that forms a substantial proportion of the plant's middle lamella of forage ingested by grazing ruminants. Methanol in the rumen is derived mainly from methoxy groups released from pectin by the action of pectin methylesterase (PME) and is subsequently used by rumen methylotrophic methanogens that reduce methanol to produce methane (CH4). Members of the genus Butyrivibrio are key pectin-degrading rumen bacteria that contribute to methanol formation and have important roles in fibre breakdown, protein digestion, and the biohydrogenation of fatty acids. Therefore, methanol release from pectin degradation in the rumen is a potential target for CH4 mitigation technologies. Here, we present the crystal structures of PMEs belonging to the carbohydrate esterase family 8 (CE8) from Butyrivibrio proteoclasticus and Butyrivibrio fibrisolvens, determined to a resolution of 2.30 Å. These enzymes, like other PMEs, are right-handed β-helical proteins with a well-defined catalytic site and reaction mechanisms previously defined in insect, plant, and other bacterial pectin methylesterases. Potential substrate binding domains are also defined for the enzymes.

Injury of the Lumbard in Degenerative Diseases of the Lumbar Spine

In this study, the pathomorphological changes that develop in the yellow ligament of the spinal canal in all types of degenerative diseases of the lumbar region of the spine were studied. As a material, fragments of corpus luteum covering the back border of the spinal canal were taken. The results show that in some degenerative diseases of the lumbar region, the yellow ligament is only hypertrophied, while in others, dystrophy, calcification develop, and ossification and deformation are observed in others. Hypertrophy and thickening of the yellow ligament of the spine develops after degenerative and inflammatory diseases and begins with the increase of histitic cells around the blood vessels and in the interstitial tissue. The hypertrophy of the yellow ligament is manifested by a sharp increase in collagen fibers, the development of the fibroelastosis process, the breakdown and destruction of elastic fibers, and a decrease in their quantity.

Gut bacterial diversity in Vespa velutina and implications for potential adaptation in South Korea.

Invasive species such as the Yellow-legged hornet (Vespa velutina), along with four other Vespa species - V. analis, V. crabro, V. ducalis, and V. mandarinia, pose significant threats to the environment, economy, and human health. This study focuses on understanding the key factors contributing to the successful invasion of these species, particularly V. velutina, in South Korea. The analysis encompasses the gut bacterial communities and stable isotopes of carbon and nitrogen of the queen hornets, aiming to identify variances in gut microbial composition and food resource utilization. The gut bacterial communities in the five Vespa species were primarily composed of Proteobacteria, with Firmicutes and Bacteroidetes present. V. velutina and V. mandarinia had higher Firmicutes abundance at the phylum level, possibly indicating an increased capacity for dietary fiber breakdown and short-chain fatty acid production, providing them with a competitive edge. No significant differences in nitrogen and carbon stable isotope values were found among the five Vespa species, suggesting that they fed on similar food sources. However, V. velutina had a higher number of unique gut bacterial operational taxonomic units (OTUs), implying adaptation through the acquisition of a distinct gut bacterial set. Significant correlations were found between the observed index and the Shannon index, and between δ15N and the observed index, suggesting that the food source diversity may influence the gut bacterial community diversity. Our study offered valuable insights regarding the adaptation of V. velutina to its new environment in South Korea. The potential role of gut microbiota in the success of invasive species was elucidated. This information is crucial for the management of invasive species, targeted control methods, and implementing preventive regulations. Further studies with larger sample sizes and comprehensive sampling are required to gain a complete understanding of the gut microbiota of Vespa species and their adaptation to new environments. This article is protected by copyright. All rights reserved.

Hydrostatic pressure drives microbe-mediated biodegradation of microplastics in surface sediments of deep reservoirs: Novel findings from hydrostatic pressure simulation experiments

Microplastics originate from the physical, chemical, or biological degradation of plastics in the environment. Once ingested by organisms at the bottom of the food chain, microplastics are passed on to organisms at higher trophic levels, posing a threat to human health. The distribution of microplastics and the metabolic pathways involved in their microbial degradation in surface sediments of drinking water reservoirs are still poorly understood. This study analyzed the occurrence patterns of microplastics and microbial community structure associated with microplastic biodegradation in surface sediments from a deep reservoir at various hydrostatic pressures. Based on the results of Fourier-transform and laser direct infrared spectroscopy, elevating the pressure resulted in altered sizes and shapes of microplastics in sediment samples with the presence of microorganisms. The influence of hydrostatic pressure on small-sized microplastics (20–500 μm) was pronounced. For instance, high pressure accelerated the breakdown of fibers, pellets, and fragments into smaller-sized microplastics. In particular, the mean size of polyethylene terephthalate microplastics decreased from 425.78 μm at atmospheric pressure to 366.62 μm at 0.7 Mpa. Metagenomic analysis revealed an increase in the relative abundances of plastic-degrading genera, such as Rhodococcus, Flavobacterium, and Aspergillus, in response to elevated pressures. Eight functional genes for biodegradation of polystyrene, polyethylene, and polyethylene terephthalate microplastics were annotated, including paaK, ladA, tphA3. Of these, tphA3 gene abundance was negatively influenced by hydrostatic pressure, providing direct evidence for the pathway by which microbial metabolism of polyethylene terephthalate led to decreased microplastic size under high pressure conditions. This study presents novel insights into hydrostatic pressure-driven microbial community structure, functional gene abundance, and key metabolic pathways associated with biodegradation of microplastics in reservoir sediments.