Microbial Influence Research Articles

Effect of Sterilization on the Change of Available Phosphorus During the Wetting and Drying Process

Wetting and drying are typical natural events in arid and semiarid areas. In order to explore the contribution of microorganisms to the change in soil phosphorus components during wetting and drying processes, soil incubation experiments were conducted on calcareous soil from Inner Mongolia grasslands. By comparing the change in various phosphorus fractions between sterilized and unsterilized soils, the microbial effect on the change in available phosphorus with soil moisture changes was studied. The results indicated that there was no significant difference in APi (NaHCO3-extractable inorganic phosphate) content between the two treatments. Sterilization caused the content of APo (NaHCO3-extractable inorganic phosphate) to significantly increase. These results suggested that soil microorganisms have a negligible influence on changes of soil available inorganic phosphorus (APi) in the present soil sample during the wetting and drying process. The change in APo may be related to the high-temperature and high-pressure sterilization processes. These results enrich our knowledge about the microbial influence on dynamics of soil available phosphorus during wetting and drying events.

Study of Antimicrobial Quality of Tobacco Leaves Extract (Nicotiana tabacum) on Aeromonas hydrophila and Escherichia coli.

ABSTRACT: Tobacco is a perennial herb and its belong to family Solanaceae. Tobacco leaves have some antimicrobial substance such as alkaloids, phenol and some essential oils. The leaves extract of this plant show some microbial Quality and influence on both gram positive and gram negative bacteria. The aim of this work to determine the effectiveness of tobacco (Nicotiana tabacum) leaves extract in inhibiting on Aeromonas hydrophila and Escherichia coli. The antibacterial test performed on Mueller Hinton Agar (MHA) media. Test result indicate the leaves extract of tobacco showed positive result in Aeromonas hyrdophilla. Tobacco extract can inhibit Aeromonas hyrdophilla growth and a clear zone are found, in case of E. coli it showed negative result in both the cases. Tobacco extract cannot inhibit E. coli growth and the diameter of the inhibitory zone is not clear. The result shown that tobacco leaf extract can be source of an active antimicrobial substance.

Stoichiometric characteristics drive the soil aggregate stability after 5 years of vegetation restoration in China

Soil stoichiometric characteristics and aggregate stability are affected by vegetation restoration in degraded land. Yet, it is not known that how the aggregate stability is related to soil stoichiometric characteristics under different vegetation restorations. A 5-year in situ experiment was conducted to investigate the effects of vegetation restoration on the composition, stability and stoichiometric properties of soil aggregates. In the northwest part of Beijing, Bromus inermis Leyss. and Medicago sativa L. were planted in a typical area of desertification, and natural restoration was used as control. Boosted regression trees (BRTs) were applied to partition the factors that control aggregate stability. The results showed that the mean weight diameter (MWD) of soil water-stable aggregates under natural restoration (CK) and Medicago sativa L. sowing treatments (AF) was significantly higher than that under the restoration of the Bromus inermis Leyss. sowing treatments (SB). Compared with CK, AF significantly increased the geometric mean diameter (GMD) water stable aggregates, while SB showed the opposite result. AF significantly increased the proportion of soil aggregates >2 mm compared with CK. AF could improve the stability of soil aggregates by increasing the proportion of large aggregates. For the stoichiometric characteristics of the aggregates, AF increased significantly the value of C/P in 0.053−0.125 mm particle size aggregates in all soil layers. The MBC/MBN ratio aggregates at depths of 0–10 cm and 10–20 cm was also significantly increased in the treatment of AF. The BRTs indicated that stoichiometric ratio is the main factor driving the stability of soil aggregates rather than microbial community characteristics and soil nutrients. The C/P is the main driving factor affecting the MWD, in which the overall stoichiometric influence accounts for 46%, followed by the microbial influence of 36%. For the GMD, MBC/MBN is the main driving factor, and the stoichiometric influence accounts for 94%. Our findings indicate that AF is beneficial to the stability of deep soil aggregates, and their stoichiometric characteristics of soil are the key factors affecting the stability of soil aggregates.

Halitosis: etiology, prevention, and the role of microbiota.

This study aims to review halitosis research, discuss its various causes, and propose effective interventions based on the underlying etiologies and mechanisms. The main research question is to identify the primary factors contributing to halitosis and appropriate strategies to address them. A comprehensive literature review was conducted on halitosis and its associated causes, including oral pathological factors, oral microbial influences, microbial metabolic pathways, gastrointestinal diseases, and gut microbiota dysbiosis. Unhealthy eating habits and an imbalance of microorganisms in the oral cavity and gastrointestinal tract were identified as primary causes of halitosis. Dental caries, periodontal disease, xerostomia, and digestive disorders like gastritis and irritable bowel syndrome were also found to be related to the development of halitosis. Due to poor oral hygiene or antibiotic use, disruption of microbial communities can result in dysbiosis, inflammation, and halitosis. Halitosis is a multifactorial condition with various underlying causes, including oral and systemic diseases. Effective interventions should be tailored based on the specific etiologies and mechanisms involved. Understanding the factors contributing to halitosis is crucial for developing appropriate treatment strategies. Enhancing oral hygiene habits, using antimicrobial drugs, or administering probiotics may help regulate oral or intestinal flora, thereby improving halitosis and overall oral health.

Exploring the Microbiome in Gastric Cancer: Assessing Potential Implications and Contextualizing Microorganisms beyond H. pylori and Epstein-Barr Virus.

While previous research has primarily focused on the impact of H. pylori and Epstein-Barr virus (EBV), emerging evidence suggests that other microbial influences, including viral and fungal infections, may also contribute to gastric cancer (GC) development. The intricate interactions between these microbes and the host's immune response provide a more comprehensive understanding of gastric cancer pathogenesis, diagnosis, and treatment. The review highlights the roles of established players such as H. pylori and EBV and the potential impacts of gut bacteria, mainly Lactobacillus, Streptococcus, hepatitis B virus, hepatitis C virus, and fungi such as Candida albicans. Advanced sequencing technologies offer unprecedented insights into the complexities of the gastric microbiome, from microbial diversity to potential diagnostic applications. Furthermore, the review highlights the potential for advanced GC diagnosis and therapies through a better understanding of the gut microbiome.

Impact of Potassium Inoculants and Biotite on Soil Microbial Population and Enzymatic Activity under Maize (Zea mays L.) Cultivation in Gangetic Plains

The study explores the impact of potassium inoculants and black mica on soil microbial populations and enzymatic activity in maize cultivated soils. Microbial communities fueled by root exudates play essential roles in nutrient cycling, plant health, and soil structure. This study investigates the effects of potassium-solubilizing bacteria (KSB) and mineral potassium on microbial populations and enzymatic activity across different growth stages of maize. The experiment was conducted in randomized block design with 14 treatments, including combinations of KSB isolates, mineral potassium, and inorganic potassium. Microbial populations (bacteria, fungi, actinomycetes, and KSB) were quantified using serial dilution and plating techniques. Enzymatic activities (dehydrogenase, phosphatase, and urease) were assessed to understand nutrient interactions and microbial influences. The findings indicate that all treatments exhibited increased microbial populations compared to the control. Notably, treatment 75% recommended potassium dose + 25% potassium from Biotite + OVPS 05 consistently demonstrated the highest microbial growth. The presence of KSB appeared crucial in enhancing bacterial and fungal populations. Additionally, enzymatic activities were significantly influenced by treatments, with 75% recommended potassium dose + 25% potassium from Biotite + OVPS 05 showing the highest dehydrogenase, alkaline phosphatase, and urease activities. These results suggest that the combination of KSB isolates and mineral potassium contributes to enhanced microbial populations and soil enzymatic activities, offering insights into sustainable agriculture practices that balance productivity and soil health. The study sheds light on the intricate relationships between microorganisms, nutrients, and soil biochemical processes, providing valuable guidance for future agricultural strategies.

Effect of Edible Coating Made from Arrowroot Flour and Kaffir Lime Leaf Essential Oil on the Quality Changes of Pork Sausage under Prolonged Refrigerated Storage.

Edible coatings are pivotal in enhancing the quality of processed meat products, acting as barriers to environmental and microbial influences by adhering directly to the food surface. Arrowroot flour, a widely produced edible tuber in Thailand, is uncharted in terms of its capability and effectiveness as an edible coating on food materials. This study aims to elucidate the composition and spectral properties of arrowroot tuber flour (ATF) to discern its viability as an edible coating for pork sausages. ATF exhibited a composition predominantly featuring carbohydrates (74.78%), moisture (9.59%), and protein (8.89%), underlining its appropriateness as an edible coating. Rapid visco amylograph revealed ATF's significant pasting capability. This study incorporated kaffir lime leaves essential oil (KEO) into the ATF coating in diverse concentrations (0-3%). Fourier-transform Infrared spectroscopy illuminated characteristic peaks and bands, showing observable shifts with the integration of KEO, yet the majority of peak placements remained essentially unchanged. The microstructure of the coatings maintained its homogeneity at heightened KEO concentrations, reflecting compatibility with ATF. The efficacy of the ATF-KEO coatings was evaluated on pork sausages, using uncoated samples as controls. While color modifications were evident, coated sausages maintained consistent moisture content, water activity, and pH levels throughout the storage duration. The coated samples also manifested enhanced textural attributes and a decline in lipid oxidation, as evidenced by reduced TBARS levels compared to controls. A subsequent microbial examination corroborated the inhibitory capacity of the ATF-KEO coatings on the microbial proliferation in pork sausages, encapsulating Total Viable Count (TVC), psychrotrophic bacteria, and lactic acid bacteria. In conclusion, the findings substantiate the promising application of ATF, especially in synergy with KEO, as a proficient edible coating for meat products. This combination aids in preserving color and texture, impeding microbial advancement, and moderating lipid oxidation, thereby contributing to the overall quality and safety of the products.

Effect of ultrasound‐assisted thin bed drying for retaining the quality of red bell pepper and compare the predictive ability of the mathematical model with artificial neural network

AbstractRed bell peppers (Capsicum annuum L.) are low in calories and high in nutrients, including vitamins A and C. Various factors such as weight loss, senescence, and microbial influence affect their quality during storage. To address this, the present study aims to preserve and retain the quality of red bell peppers using ultrasound‐assisted thin‐bed drying. The results were analyzed using an Artificial Neural Network (ANN) for more accurate prediction of variables involved in the process. Variations in moisture ratio and moisture content during drying were calculated and predicted. The Midilli model provided satisfactory curve fitting at an air velocity of 1.5 m/s, with R2 = 0.9993, χ2 = 0.0002, and RMSE = 0.0134. The two‐term and modified page models fit better with drying curves at air velocities of 2 and 2.5 m/s, with R2 = 0.9995, χ2 = 0.002, RMSE = 0.0016 and R2 = 0.9996, χ2 = 0.00003, RMSE = 0.00003, respectively. However, the trained standard backpropagation ANN algorithm demonstrated excellent predictive ability, outperforming the mathematical models with R2 = 0.9989 (training), MSE = 0.0001 (training), and R2 = 0.9996 (testing), MSE = 0.0002 (testing). Most importantly, the ultrasound‐assisted drying process retains the essential nutrients in red bell peppers, including vitamin C, carotenoids, polyphenols, and flavonoids, across various conditions. The antioxidant potential, as measured by DPPH and FRAP assays, remains largely unchanged compared to untreated samples. However, ABTS activity shows a significant difference at an air velocity of 1.5 m/s and temperatures of 60 and 70°C compared to the control sample.Practical applicationsIn terms of vitamins and antioxidants, red bell peppers are a great provider. Interestingly, capsaicin, the substance responsible for spiciness, is found in very little to no quantity in red bell peppers making it appealable to consumers. To achieve a certain level of processing, the quality of the dried product needs to be monitored while fulfilling the needs of consumers. Particularly, the quality‐determining parameters were vitamin C, total carotenoids, total polyphenols, total flavonoid content, DPPH, ABTS, and FRAP activity. These qualities were retained after drying with the potential novel combination of ultrasound with thin bed drying at low temperatures and air velocity. This means that the bioactive compounds responsible for improving the health of humans are readily available in dried form all year round. The drying kinetics were modeled, predicted, and compared with mathematical and ANN models.

Influence of cropping sequences on soil suppressive/conduciveness against Sclerotium rolfsii in different agro-climatic zones of West Bengal, India

Aim: To study the influence of different cropping sequences (CSs) on soil suppressive or conduciveness towards Sclerotium rolfsii in different agro-climatic zones (ACZs) of West Bengal, India. Methodology: Farmer’s field surveys were conducted to explore the suppressive activity of various crop rhizosphere during each winter, October to January (2016-2019). The survey was done in 14 districts of five ACZs in West Bengal (India), and the total surveyed sample size was 511. The S. rolfsii disease incidence (DI%) data of Rabi crop in surveyed areas and sclerotial population, soil suppressive index, FDA hydrolysis, dehydrogenase activity and culturable microbial assay were performed. Results: In this data set (n=511), the foremost soils belonged to no suppressive category (74.47%), followed by slight suppressive category (20.74%). Negligible number of soils belonged to moderate (0.39%) and strong suppressive (0.39%) category. The population of Pseudomonads was higher in both strong and moderate suppressive soil rather than slight and no suppressive soils. Culturable population of soil Pseudomonads, Bacillus and Actinomycetes varied in five different ACZs. Interpretation: Paddy-brassica vegetables, paddy-maize and paddy-cucurbits vegetable-based CSs exhibited relatively high soil uppressiveness whereas paddy-legumes, jute-paddy-legume vegetables and pulses based CSs showed high soil conduciveness towards S. rolfsii. Soil microbial influences on crop rhizosphere along with “crop rotation effect” was the key reason for the disease suppressive activity. Key words: Agro-climatic zones, Crop rotation, FDA hydrolysis, Rhizosphere, S. rolfsii, Suppressive soil

Etiopathogenesis of primary acquired nasolacrimal duct obstruction (PANDO).

Primary acquired nasolacrimal duct obstruction, or PANDO, is a common adult lacrimal drainage disorder. The current treatment modality of dacryocystorhinostomy to bypass the obstructed nasolacrimal duct has excellent outcomes. However, the understanding of the disease etiopathogenesis needs to be revisited. There are not many studies that specifically assessed any hypothesis or ones that convincingly put forth the presumed or confirmed interpretations regarding the PANDO pathogenesis or the mechanisms or pathways involved therein. Histopathological evidence points to recurrent inflammation of the nasolacrimal duct, subsequent fibrosis, and the resultant obstruction. The disease etiopathogenesis is considered multifactorial. Several implicated suspects include anatomical narrowing of the bony nasolacrimal duct, vascular factors, local hormonal imbalance, microbial influence, nasal abnormalities, autonomic dysregulation, surfactants, lysosomal dysfunction, gastroesophageal reflux, tear proteins, and deranged local host defenses. The present work reviewed the literature on the etiopathogenesis of primary acquired nasolacrimal duct obstruction (PANDO) to gain insights into the present state of the understanding and the high-value translational implications of precisely decoding the disease etiology.

Well-hidden methanogenesis in deep, organic-rich sediments of Guaymas Basin

Deep marine sediments (>1mbsf) harbor ~26% of microbial biomass and are the largest reservoir of methane on Earth. Yet, the deep subsurface biosphere and controls on its contribution to methane production remain underexplored. Here, we use a multidisciplinary approach to examine methanogenesis in sediments (down to 295 mbsf) from sites with varying degrees of thermal alteration (none, past, current) at Guaymas Basin (Gulf of California) for the first time. Traditional (13C/12C and D/H) and multiply substituted (13CH3D and 12CH2D2) methane isotope measurements reveal significant proportions of microbial methane at all sites, with the largest signal at the site with past alteration. With depth, relative microbial methane decreases at differing rates between sites. Gibbs energy calculations confirm methanogenesis is exergonic in Guaymas sediments, with methylotrophic pathways consistently yielding more energy than the canonical hydrogenotrophic and acetoclastic pathways. Yet, metagenomic sequencing and cultivation attempts indicate that methanogens are present in low abundance. We find only one methyl-coenzyme M (mcrA) sequence within the entire sequencing dataset. Also, we identify a wide diversity of methyltransferases (mtaB, mttB), but only a few sequences phylogenetically cluster with methylotrophic methanogens. Our results suggest that the microbial methane in the Guaymas subsurface was produced over geologic time by relatively small methanogen populations, which have been variably influenced by thermal sediment alteration. Higher resolution metagenomic sampling may clarify the modern methanogen community. This study highlights the importance of using a multidisciplinary approach to capture microbial influences in dynamic, deep subsurface settings like Guaymas Basin.

Effect of Microbial Reinforcement on Polyphenols in the Acetic Acid Fermentation of Shanxi-Aged Vinegar

Polyphenols are important functional substances produced in the acetic acid fermentation (AAF) of Shanxi aged vinegar (SAV). Previous studies have shown that the metabolic activity of microorganisms is closely related to polyphenol production and accumulation. In this study, microorganisms in the AAF of SAV were analyzed to explore how to increase the polyphenol yield by changing the microorganisms and reveal the potential mechanism of the microbial influence on the polyphenol yield. Macrotranscriptome analysis showed that acetic and lactic acid bacteria dominated the AAF fermentation process and initially increased and decreased. Spearman correlation analysis and verification experiments showed that the co-addition of Acetobacter pasteurianus and Lactobacillus helveticus promoted the accumulation of polyphenols, and the total polyphenol content increased by 72% after strengthening.

Evaluating optimized volatile fatty acids production from carbon-rich wastewater during hydrolysis acidification process by Fe(Ⅱ) and Fe(Ⅲ) addition

Volatile fatty acids (VFAs), a value product of hydrolysis acidification (HA) has been grasped ample eyeballs. Fe(Ⅱ) and Fe(Ⅲ) were applied to enhance VFAs production from carbon-rich starch wastewater in this investigation. VFAs productivity was improved 6.5–15.2% than the control system when Fe(Ⅱ) and Fe(Ⅲ) were supplemented. The enrichment of key functional HA microbes identified by molecular ecological network analysis (MENA) and improved key enzymes’ activity contributed to promotion of organics hydrolysis, triggering high VFAs yields. After further analysis, it was clarified that the microbial metabolism's influence on pH and the presence of Fe2+ in the systems were key factors contributing to the improvement of the microbial community structure and the activity of key enzymes, respectively. Detailed comparison analysis was also conducted between RFe(Ⅱ) and RFe(Ⅲ) systems. Totally, from the perspective of performance and environmental, Fe(Ⅱ) and Fe(Ⅲ) have great engineering application potential on enhancing VFAs production, especially for Fe(Ⅱ).

Microbiota-produced indole metabolites disrupt mitochondrial function and inhibit Cryptosporidium parvum growth

Cryptosporidiosis is a leading cause of life-threatening diarrhea in young children in resource-poor settings. To explore microbial influences on susceptibility, we screened 85 microbiota-associated metabolites for their effects on Cryptosporidium parvum growth invitro. We identify eight inhibitory metabolites in three main classes: secondary bile salts/acids, a vitamin B6 precursor, and indoles. Growth restriction of C.parvum by indoles does not depend on the host aryl hydrocarbon receptor (AhR) pathway. Instead, treatment impairs host mitochondrial function and reduces total cellular ATP, as well as directly reducing the membrane potential in the parasite mitosome, a degenerate mitochondria. Oral administration of indoles, or reconstitution of the gut microbiota with indole-producing bacteria, delays life cycle progression of the parasite invitro and reduces the severity of C.parvum infection in mice. Collectively, these findings indicate that microbiota metabolites impair mitochondrial function and contribute to colonization resistance to Cryptosporidium infection.

Coarsening of tufa textures through early diagenesis: Modern and fossil examples from Bonito region (Central-West, Brazil)

Diagenetic modifications in tufa are difficult to distinguish from primary processes as they occur soon after sedimentation. Active and inactive fossil, probably Pleistocene to mid-Holocene, tufas in the Bonito region (Brazilian Midwest) were investigated to characterize primary and early diagenetic changes. Textural observations, analyses of cathodoluminescence and point counting were performed to identify the main diagenetic processes in active and fossil tufa facies. Lithification, coarsening of the textures, and degradation of organic matter are the main diagenetic changes. Although in some cases microspar and some spar crystals are syn-sedimentary, most of them occur as early diagenetic products. Microbial influence, anisotropy of the porosity and dominant capillarity-controlled processes are all related to lithification. Micrite grading to microspar occurring in both modern and inactive tufa is interpreted as neomorphism. Inactive tufa presents cloudy spar crystals interpreted as neomorphic (pseudospar) and clear spar crystals formed as cements. High correlation coefficients and negative trends between contents of micrite-microspar (active tufa) and micrite-spar (inactive tufa) suggest neomorphism as the main diagenetic process, in agreement with textural observations in thin section. The lack of correlation between pores and micrite, microspar and spar in both tufas suggests that the main diagenetic processes are not pore-consuming, at the scale of the present work. Although the textural differences between active and inactive tufa from Bonito region are very subtle, all the diagenetic changes were limited to the time spanning the active depositional system.

Gut Microbiota and Microbial Metabolism in Early Risk of Cardiometabolic Disease.

Cardiometabolic disease comprises cardiovascular and metabolic dysfunction and underlies the leading causes of morbidity and mortality, both within the United States and worldwide. Commensal microbiota are implicated in the development of cardiometabolic disease. Evidence suggests that the microbiome is relatively variable during infancy and early childhood, becoming more fixed in later childhood and adulthood. Effects of microbiota, both during early development, and in later life, may induce changes in host metabolism that modulate risk mechanisms and predispose toward the development of cardiometabolic disease. In this review, we summarize the factors that influence gut microbiome composition and function during early life and explore how changes in microbiota and microbial metabolism influence host metabolism and cardiometabolic risk throughout life. We highlight limitations in current methodology and approaches and outline state-of-the-art advances, which are improving research and building toward refined diagnosis and treatment options in microbiome-targeted therapies.

Microbial Influences on Immune Checkpoint Inhibitor Response in Melanoma: The Interplay between Skin and Gut Microbiota.

Immunotherapy has revolutionized the treatment of melanoma, but its limitations due to resistance and variable patient responses have become apparent. The microbiota, which refers to the complex ecosystem of microorganisms that inhabit the human body, has emerged as a promising area of research for its potential role in melanoma development and treatment response. Recent studies have highlighted the role of microbiota in influencing the immune system and its response to melanoma, as well as its influence on the development of immune-related adverse events associated with immunotherapy. In this article, we discuss the complex multifactorial mechanisms through which skin and gut microbiota can affect the development of melanoma including microbial metabolites, intra-tumor microbes, UV light, and the immune system. In addition, we will discuss the pre-clinical and clinical studies that have demonstrated the influence of different microbial profiles on response to immunotherapy. Additionally, we will explore the role of microbiota in the development of immune-mediated adverse events.

Microbial Influence on the Mobility of +3 Actinides from a Salt-Based Nuclear Waste Repository.

Biologically enhanced transport of radionuclides is one of several processes that can affect the performance of a nuclear waste repository. In this work, several microbial isolates from the Waste Isolation Pilot Plant (WIPP) were tested for their influence on the concentration of neodymium, as an analog for +3 actinides, in simple sodium chloride solutions and in anoxic WIPP brines. Batch sorption experiments were carried out over a period of 4-5 weeks. In many cases, the effect on neodymium in solution was immediate and extensive and assumed to be due to surface complexation. However, over time, the continued loss of Nd from the solution was more likely due to biologically induced precipitation and/or mineralization and possible entrapment in extracellular polymeric substances. The results showed no correlation between organism type and the extent of its influence on neodymium in solution. However, a correlation was observed between different test matrices (simple NaCl versus high-magnesium brine versus high-NaCl brine). Further experiments were conducted to test these matrix effects, and the results showed a significant effect of magnesium concentration on the ability of microorganisms to remove Nd from solution. Possible mechanisms include cation competition and the alteration of cell surface structures. This suggests that the aqueous chemistry of the WIPP environs could play a larger role in the final disposition of +3 actinides than the microbiology.

Variable characteristics of microbial communities and volatile organic compounds during post-harvest storage of wild morel mushrooms

Wild morel mushroom is one of the most popular mushrooms, but fresh morels have a short shelf life and are highly susceptible to microbial influences that can lead to spoilage and changes in volatile organic compounds. Therefore, the microbial communities (bacteria and fungi) were studied by high-throughput sequencing technology on wild morel mushrooms in a post-harvest environment at 4 ℃. The volatile organic compounds (VOCs) of wild morel mushrooms were evaluated by headspace solid-phase microextraction (HS-SPME) in combination with gas chromatography-mass spectrometry (GC-MS) during storage. The results showed that there were 41 given genera of bacteria and 48 given genera of fungi with abundance > 0.01% during the whole storage period. Among them, bacteria: Pseudomonas, Pedobacter and Flavobacterium; fungi: Cystofilobasidium, Aspergillus and Mucor had a greater impact on wild morel mushrooms during storage, especially Pseudomonas, whose abundance was consistently elevated and accounted for the largest share (47.51–73.73%). The main VOCs of wild morel mushrooms consist of aldehydes, alcohols, alkanes, ketones, phenols, esters and acids. Among them, 3-Octanone is predominant, but its content has been decreasing. The analysis showed a strong correlation between microorganisms and VOCs (P < 0.05, |r| > 0.9). Among them, Pseudomonas was correlated with 4 VOCs; Cystofilobasidium with 8 VOCs; Aspergillus with 7 VOCs; and Mucor with 7 VOCs. This suggests that microbes are crucial to the degradation and VOCs of morels during spoilage. The findings of the research provide information database for post-harvest preservation of morel mushrooms and efficient control of their spoilage.

The effects of disturbance on the microbial mediation of sediment stability

AbstractIn coastal areas, biofilms are often subject to disturbance by hydrodynamic forcing, bioturbation and human activities. These factors affect the influences biofilms have on the sediment. To reveal these effects, we studied laboratory‐incubated and field‐collected biotic sediments reworked by disturbances, and examined their stabilities and three‐dimensional microstructures using laboratory annular flume tests and a wet‐staining X‐ray microcomputed tomography method. We find that, when subject to disturbance, biofilms do not always establish mat‐like matrices that firmly armor the seabed and bio‐stabilize sediments, but instead, have a range of effects on sediment stability, including both bio‐stabilization and destabilization. Disturbance considerably alters microbial influences on sediment stability, but is not the only control. Given equal disturbance, whether or not sediments are bio‐stabilized largely depends on the state of bio‐sediment formation. At a relatively well‐developed state, an organic‐rich, adhesive polymer network tightly interconnects large amounts of sediment particles into aggregates, forms complex internal structures, and enhances sediment stability. By contrast, some bio‐sediment formations only ever reach a less well‐developed state, where scattered organic patches bind relatively few particles into aggregates and reduce sediment stability. Microbial growth likely has two opposing effects on sediment stability, by enhancing either weight/friction or lift/drag on aggregated particles. The former has the positive effect of enhancing sediment stability, whereas the latter can result in greater flow resistance and so have the opposite effect. A conceptual framework is put forward to characterize the different states of bio‐sediment formation and their distinct effects on sediment stability.