Genera Of Bacteria Research Articles

Diversity and characteristics of plant immunity–activating bacteria from Brassicaceae plants

BackgroundMicroorganisms that activate plant immune responses are useful for application as biocontrol agents in agriculture to minimize crop losses. The present study was conducted to identify and characterize plant immunity–activating microorganisms in Brassicaceae plants.ResultsA total of 25 bacterial strains were isolated from the interior of a Brassicaceae plant, Raphanus sativus var. hortensis. Ten different genera of bacteria were identified: Pseudomonas, Leclercia, Enterobacter, Xanthomonas, Rhizobium, Agrobacterium, Pantoea, Rhodococcus, Microbacterium, and Plantibacter. The isolated strains were analyzed using a method to detect plant immunity–activating microorganisms that involves incubation of the microorganism with tobacco BY-2 cells, followed by treatment with cryptogein, a proteinaceous elicitor of tobacco immune responses. In this method, cryptogein-induced production of reactive oxygen species (ROS) in BY-2 cells serves as a marker of immune activation. Among the 25 strains examined, 6 strains markedly enhanced cryptogein-induced ROS production in BY-2 cells. These 6 strains colonized the interior of Arabidopsis plants, and Pseudomonas sp. RS3R-1 and Rhodococcus sp. RS1R-6 selectively enhanced plant resistance to the bacterial pathogens Pseudomonas syringae pv. tomato DC3000 and Pectobacterium carotovorum subsp. carotovorum NBRC 14082, respectively. In addition, Pseudomonas sp. RS1P-1 effectively enhanced resistance to both pathogens. We also comprehensively investigated the localization (i.e., cellular or extracellular) of the plant immunity–activating components produced by the bacteria derived from R. sativus var. hortensis and the components produced by previously isolated bacteria derived from another Brassicaceae plant species, Brassica rapa var. perviridis. Most gram-negative strains enhanced cryptogein-induced ROS production in BY-2 cells via the presence of cells themselves rather than via extracellular components, whereas many gram-positive strains enhanced ROS production via extracellular components. Comparative genomic analyses supported the hypothesis that the structure of lipopolysaccharides in the outer cell envelope plays an important role in the ROS-enhancing activity of gram-negative Pseudomonas strains.ConclusionsThe assay method described here based on elicitor-induced ROS production in cultured plant cells enabled the discovery of novel plant immunity–activating bacteria from R. sativus var. hortensis. The results in this study also suggest that components involved in the ROS-enhancing activity of the bacteria may differ depending largely on genus and species.

Infection patterns of ‘Candidatus Liberibacter europaeus’ in Cacopsylla oluanpiensis, a psyllid pest of Pittosporum pentandrum

‘Candidatus Liberibacter’ is a genus of plant-associated bacteria that can be transmitted by insects of the superfamily Psylloidea. Since many members of this genus are putative causal agents of plant diseases, it is crucial in studying their interactions with the psyllid vectors. However, previous studies have mainly focused on few species associated with diseases of economic significance, and this may potentially hinder the development of a more comprehensive understanding of the ecology of ‘Ca. Liberibacter’. The present study showed that an endemic psyllid species in Taiwan, Cacopsylla oluanpiensis, is infected with a species of ‘Ca. Liberibacter’. The bacterium was present in geographically distant populations of the psyllid and was identified as ‘Ca. Liberibacter europaeus’ (CLeu), a species which generally does not induce plant symptoms. Analysis of CLeu infection densities in male and female C. oluanpiensis with different abdominal colors using quantitative polymerase chain reaction revealed that CLeu infection was not significantly associated with psyllid gender and body color. Instead, CLeu infection had a negative effect on the body sizes of both male and female psyllids, which is influenced by bacterial titer. Investigation on CLeu’s distribution patterns in C. oluanpiensis’s host plant Pittosporum pentandrum indicated that CLeu does not behave as a plant pathogen. Also, results showed that nymph-infested twigs had a greater chance of carrying high loads of CLeu, suggesting that ovipositing females and the nymphs are the main source of the bacterium in the plants. This study is not only the first to formally report the presence of CLeu in C. oluanpiensis and plants in the family Pittosporaceae, but also represents the first record of the bacterium in Taiwan. Overall, the findings in this work broaden the understanding of associations between psyllids and ‘Ca. Liberibacter’ in the field.

The Prevalence of blaCTX-M, blaTEM Genes in Bacteria Isolated From Bladder Cancer Patients with Urinary Tract Infections

Urinary tract infections (UTIs) are among the most prevalent infections in cancer patients . Two hundred urine samples were taken from patients with bladder cancer between the dates of 1 April 2021 and 15 October 2021 while they were enrolled in third floor Ghazi Al- Hariri Hospital, Medical City, Baghdad Province, and private clinics in Nasiriyah Province (100 from patients treated with MMC and 100 from patients treated with BCG). Forty urine samples were taken from patients with UTI without Bladder Ca (control). The most commonly pathogens were Escherichia coli , followed by Klebsiella pneumoniae , Pseudomonas aeruginosa and Staphyllococcus aureus and other genera of UTI bacterium. The total ESBLs Producers in the current study from 40 isolates was (27)72.5%.The highest ESBLs Producer in all Groups was E.coli followed by K.pneumoniae and P.aeruginosae . According to PCR out of 38 Clinical specimen from all groups , results of the bla CTX-M gene indicated its presence in 21 isolate(55.2%),while the presence of bla TEM gene was 26(68.4%) of total isolates.

Identification of Wolbachia pipientis and phylogenetic studies of plodia interpuntella populations in different cities of Pakistan

Wolbachiapipientis is genus of gram-negative bacteria which infect the members of phylum arthropoda, mainly affects the class insecta and some nematodes. Wolbachiapipientis are the common bacterial symbionts of the insects. About 25 to 70% of insect species are estimated to be the host of Wolbachiapipientis. Infection of these bacteria can alter the reproduction and biology of the host. Even some host species can not reproduce without Wolbachiapipientis infection. Due to thisreason, Wolbachiapipientis are used to control the population of pest species. A major reseach objective is the detection of Wolbachiapipientis in the Plodiainterpuntella populations of different cities of Pakistan leading towards its phylogenetic descriptions through molecular markers. Plodia interpuntella commonly called Indian meal moth. This insect is the major and most destructive pest of food grains such as, rice, maize and other cereals. The presence of this pest is relating with occurrence of such grains in homes and grocery stores. Indian meal moth feeding reduces the dry weight of stored grains. This study was done to estimates the economic and yield losses of food gains due to Plodia interpuntella in the different cities of Pakistain such as (Faisalabad, Jhang and Layyah) from Punjab, (Peshawar) from KPK and (Hyderabad) from Sindh. Firstly, the Collection of Plodiainterpunctella was completed from mention areas, and the pest was identified through morphologically, molecular analysis, eggs and larval instar. The results of our study showed that, the pest infection rate was ot similar in all the citites. Its majorly attack was identified in Faisalabd, Jhang, Layyah, Peshwar and Hyderabad gradually. During the study, pest infection rate was calculated in four months, July, August, September and October. The attack of pest was maximum in the start of July and minimum at the end of Octobor in stored grains. The results were calculated by using DNA extraction. The statistical analysis was performed through SPSS.

Isolation and Characterization of Local Microorganisms (MOL) of Bamboo Shoots (Dendrocalamus asper) and Its Effect on the Growth of Pakcoy Plants (Brassica rapa L.)

MOL is an organic fertilizer made from fermented natural materials that contain carbohydrates and many macro and micro nutrients. This type of fertilizer also contains microorganisms that its contribute towards role as biofertilizer. One potential organic material for MOL that is easily available is bamboo shoots. Bamboo shoots contain important nutrients which can improve plant growth and development. The purpose of this study was to determine what bacteria are contained in bamboo shoot MOL and to determine its effect on growth in pakcoy plants (Brassica rapa L). This research is an experimental study using RAL (Complete Randomized Design), including: isolation and characterization of bamboo shoot MOL, application of MOL to pakcoy plants (Brassica rapa L) containing bacterial isolates from bamboo shoot MOL. The observed parameters include plant height, root length, number of leaves and wet weight of pakcoy plants followed by statistical analysis using analysis of variance (ANOVA) and characterization results on isolates obtained based on Bergey's Manual of Determinative Bacteriology. From the research results obtained that the prediction of the genus of bacteria contained in bamboo shoots is Lactobacillus, Streptococcus Sp, Saccharococcus, Veillonella sp, Azotobacter, and Rhizobacter which play a role in accelerating decomposition so as to produce the best quality fertilizer and MOL contained in bamboo shoots has a significant effect on the growth of pakcoy (Brassica rapa L). The best result for MOL bamboo shoots that are good for pakcoy plant growth is obtained at a concentration of 150ml / L so that MOL bamboo shoots have the potential for pakcoy plant growth.

Methods for Electroporation and Transformation Confirmation in <em>Limosilactobacillus reuteri</em> DSM20016

Lactobacillus were an incredibly large, diverse genus of bacteria comprising 261 species, several of which were commensal strains with the potential for use as a chassis for synthetic biological endeavors within the gastrointestinal tract. The wide phenotypic and genotypic variation observed within the genus led to a recent reclassification and the introduction of 23 novel genera. Due to the breadth of variations within the old genera, protocols demonstrated in one member may not work as advertised with other members. A lack of centralized information on how exactly to manipulate specific strains has led to a range of ad hoc approaches, often adapted from other bacterial families. This can complicate matters for researchers starting in the field, who may not know which information does or does not apply to their chosen strain. In this paper, we aim to centralize a set of protocols with demonstrated success, specifically in the Limosilactobacillus reuteri strain designation F275 (other collection numbers: DSM20016, ATCC23272, CIP109823), along with troubleshooting advice and common issues one may encounter. These protocols should enable a researcher with little to no experience working with L. reuteri DSM20016 to transform a plasmid, confirm transformation, and measure system feedback in a plate reader via a reporter protein.

The pathogenicity of Cronobacter in the light of bacterial genomics

Cronobacter spp. is a genus of Gram-negative bacteria belonging to the family Enterobacteriaceae. Species of the genus Cronobacter, particularly C. sakazakii, are implicated in the development of severe disease in newborns, which occurs with necrotizing enterocolitis, sepsis and meningitis. The disease has been frequently associated with powdered infant formula (PIF) and can therefore occur in the form of outbreaks. The genus Cronobacter has undergone extensive diversification in the course of its evolution, with some species being clearly pathogenic to humans while the impact of other species on human health is uncertain or unknown. Whole genome sequencing is used both in population genetic studies to identify the limited number of genotypes associated with the disease and to detect genes associated with antibiotic resistance or virulence, ultimately allowing more precise epidemiological links to be established between pediatric disease and infant foods.

Analysis on driving factors of microbial community succession in Jiuyao of Shaoxing Huangjiu (Chinese yellow rice wine)

The microbial ecosystem of fermented food is greatly disturbed by human activities.Jiuyao is important saccharification starter for brewing huangjiu. The interaction between environmental factors and microorganisms significantly affected the microbial community structure at different stages of Jiuyao manufacturing. This study combined environmental factor analysis and high-throughput sequencing technology to comprehensively analyze the specific changes of microbial community and environmental factors in each fermentation stage of Jiuyao production and their correlation. The results showed that the activities of liquefaction enzyme, glycosylation enzyme and acid protease reached the highest value on the 8 th day (192 h) after the beginning of fermentation, and the cellulase activity reached the highest value at the end of fermentation. Pediococcus（37.5 %-58.2 %）, Weissella（9.2 %-27.0 %） and Pelomonas（0.1 %-12.1 %） were the main microbial genera in the genus bacteria, and Saccharomycopsis（37.1 %-52.0 %）, Rhizopus（12.5 %-31.0 %） and Saccharomyces（4.0 %-20.5 %） were the main microbial genera in the genus fungi. The results of correlation analysis showed that the microbial communities in Jiuyao were closely related to environmental factors. Most microbial communities were positively correlated with temperature, but negatively correlated with ambient humidity, CO2 concentration, acidity and water content of Jiuyao. In addition, the transcription levels of enzymes related to microbial glucose metabolism in Jiuyao were higher in the late stage of Jiuyao fermentation. Interestingly, these enzymes had high transcription levels in fungi such as Saccharomycopsis, Rhizopus and Saccharomyces, as well as in bacteria such as Pediococcus and Lactobacillus. This study provides a reference for revealing the succession rule of microbial community structure caused by environmental factors during the preparation of Jiuyao in Shaoxing Huangjiu.

Penaeus vannamei challenged with a Vibrio parahaemolyticus AHPND strain shows hepatopancreatic microbiota imbalance

White shrimp, Penaeus vannamei, farming represents one of the most important aquaculture activities in the world with a high growth rate. However, intensification processes induce negative side effects on the health of the organism, associated with a dysbiosis phenomenon. Consequently, illnesses, mainly attributable to Vibrio genus bacteria, have been reported in shrimp ponds. Studying the diversity and ecology of the associated bacteria in aquaculture systems is essential to prevent and control diseases. Therefore, the present study analyzes the bacterial load and microbial population variation in P. vannamei hepatopancreases infected with a pathogenic Vibrio parahaemolyticus strain (so-called CVP2) associated with acute hepatopancreatic necrosis disease (AHPND) under controlled conditions. The results showed an important change in the microbial community structure of the P. vannamei hepatopancreas. Furthermore, the presence of the Vibrio genus considerably increased and clearly dominated compared with the control. Dysbiosis of the hepatopancreatic microbiota and constrictions in the hepatopancreatic tubules (characteristic signs of in the early stage of AHPND) could be observed before the visible manifestation of the disease.

Gut Microbiota Signatures Are Associated With Psychopathological Profiles in Patients With Ulcerative Colitis: Results From an Italian Tertiary IBD Center.

Several patients with ulcerative colitis (UC) suffer from psychiatric disorders, such as major depressive disorder, anxiety, or bipolar disorder, and show specific personality traits. Despite this, there are few data about personality profiles' characterization in UC patients and about correlation of their psychopathological profile with their intestinal microbiota.The aim of our study is to analyze the psychopathological and personality profile of UC patients and correlate it with specific signatures of their gut microbiota. This is a prospective interventional longitudinal cohort study. We enrolled consecutive patients affected by UC attending to the IBD Unit of Center for Digestive Disease of "A. Gemelli" IRCCS Hospital in Rome and a group of healthy subjects, matched for specific characteristics. Each patient was evaluated by a gastroenterologist and a psychiatrist. Moreover, all participants underwent psychological tests and a collection of stool samples. We recruited 39 UC patients and 37 healthy subjects. Most patients showed high level of alexithymia, anxiety symptoms, depressive symptoms, as well as neuroticism and hypochondria, with obsessive-compulsive features at the behavioral level, which significantly impaired their quality of life and abilities at work. Gut microbiota analysis in UC patients demonstrated an increase in actinobacteria, Proteobacteria and Saccharibacteria (TM7), with a reduction in verrucomicrobia, euryarchaeota and tenericutes. Our study confirmed the presence of high levels of psycho-emotional distress in UC patients, alongside alterations of the intestinal microbiota, and highlighted some families and genera of bacteria (Enterobacteriaceae, Streptococcus, Veillonella, Klebsiella, and Clostridiaceae) as potential markers of an altered gut-brain axis in these patients.

Genome Sequences of Rhodoplanes serenus and Two Thermotolerant Strains, Rhodoplanes tepidamans and "Rhodoplanes cryptolactis," Further Refine the Genus.

Rhodoplanes is a small genus of anoxygenic purple nonsulfur bacteria belonging to the family Nitrobacteraceae in the class Alphaproteobacteria. We sequenced the genomes of one mesophilic and two thermotolerant strains, and whole-genome-based comparisons confirmed suspected close similarities and synonyms between different species in the genus.

Probiotic and technological characterization of selected Lactobacillus strains isolated from different egyptian cheeses

BackgroundFresh milk and natural environmental conditions are used to produce traditional cheeses. Such cheeses are produced by dozens of different types of microbes. Non-starter lactobacilli are the most responsible genus of lactic acid bacteria exhibiting key technological and health promoting traits. The purpose of this study is to isolate Lactobacillus bacteria from conventional Egyptian cheeses and analyse their probiotic potential and technological properties.ResultsLactobacillus isolates (33 isolates) were isolated from different Egyptian cheeses. Our results revealed that 18.18% of the isolates were fast-acidifying, 30.3% were medium-acidifying and 51.5% were slow-acidifying isolates. The results of autolytic activity showed that 24.3% of the isolates were good autolysis, 33.3% were fair autolysis, while 42.4% were poor autolysis. Fifteen isolates produced exopolysaccharides, while 9 isolates exhibited antimicrobial activities against Lactobacillus bulgaricus 340. All the isolates were resistant to pH 3 for 3 h except isolate No. 15 (MR4). The growth rate of the isolates ranged from 42.25 to 85.25% at 0.3% bile salts after 3 h of incubation. The surviving percentage of the Lactobacillus isolates decreased with increasing incubation time or the percentage of bile salts greater than 0.3%. All the isolates grew after incubation in artificial gastric and intestinal fluids. The auto-aggregation of 15 isolates ranged from 43.13 to 72.77%. Lacticaseibacillus paracasei BD3, Lactiplantibacillus plantarum BR4 and Limosilactobacillus fermentum MR2 were sensitive to the majority of the tested antibiotics and showed good bile salt hydrolase activity.ConclusionL. paracasei BD3, L. plantarum BR4 and L. fermentum MR2 were isolated from Egyptian cheeses and showed probiotic and technological characterization, which are valuable for their practical application as starters, adjunct and protective cultures in cheese making.

Microbiota transfer following liver surgery involves microbial extracellular vesicle migration that affects liver immunity.

Short-term perioperative administration of probiotics was shown to alleviate postoperative complications and promote liver recovery among patients undergoing resection for liver malignancy. The mechanisms by which probiotic bacteria effectively influence the gut microbiome composition during the perioperative time are controversial. Here, we aim to elucidate the short-term direct biological effect of probiotic microbiota-derived vesicles on host liver cells during the perioperative period. Probiotic-derived vesicles (pbMVs) were administered postoperatively. pbMVs were isolated and characterized from probiotics, mainly from the bacteria genus Lactobacillus, Bifidobacterium, and Lactococcus. Mice underwent bile duct ligation, sham laparotomy (SHAM), or 70% partial hepatectomy (70%PH). pbMVs were tracked in vivo, and intrahepatic cellular and molecular aspects were analyzed by flow cytometry and qRT-PCR techniques. Liver sinusoidal endothelial cells (LSECs) analysis for Vascular Cell Adhesion Molecule-1(VCAM-1) expression following pbMV stimulation of cultured liver non-parenchymal cells which had been activated by LPS. The administered pbMV rapidly translocated to the liver after surgery. pbMV administrations following surgeries enhanced neutrophil clearance; there was a dramatic decline in the liver neutrophil-to-lymphocyte ratio Ly6G+/CD3+ and an increase in IL6 levels. pbMVs reduced intrahepatic VCAM1 and ICAM2 expression compared with control following SHAM and decrease in IL10 levels following 70%PH. The administration of pbMV improved liver regeneration 72 hours following surgical liver resection with a significant decrease in IL17 expression. pbMVs modulated VCAM-1 on liver sinusoidal endothelial cells in liver cell culture. Our study findings provide mechanistic insights into the liver-gut axis following surgery and illustrate how probiotic vesicles can reduce adhesion molecule expression and affect immune cell invasion and liver immunity, resulting in improved liver recovery following hepatic surgery.

Natural emulsifiers lecithins preserve gut microbiota diversity in relation with specific faecal lipids in high fat-fed mice

Synthetic emulsifiers promote metabolic syndrome and considerably alter gut microbiota. Data is lacking regarding natural emulsifiers like plant lecithins, a polar lipid-rich source of 18:3n-3 PUFA (ALA). For 13 weeks, male Swiss mice were fed ALA-replete semi-synthetic high-fat diet (HFD) including lecithin from rapeseed (RL) or soy, vs 2 HFD-controls devoid of lecithin (ALA-replete; low-ALA), vs Chow. Lecithins did not enhance HFD-induced adiposity nor increased inflammation, did not alter gut barrier markers and caecal bile acids, and contributed to n-3 PUFA status. Lecithins improved gut microbiota diversity. RL (10% in fat) even restored α-diversity similar to Chow, increased Lachnospiraceae NK4A136, Lactobacillus and Ruminococcaceae UCG-014 groups, and decreased Blautia genus bacteria. The abundance of most beneficial lecithin-enhanced bacteria was positively correlated to the amount of faecal polar lipid-bound ALA. These findings show that lecithins can beneficially affect the gut microbiota in association with changes in lipid residues in the distal gut.

Bovine Airway Models: Approaches for Investigating Bovine Respiratory Disease.

Bovine respiratory disease (BRD) is a multifactorial condition where different genera of bacteria, such as Mannheimia haemolytica, Histophilus somni, Pasteurella multocida, and Mycoplasma bovis, and viruses, like bovine respiratory syncytial virus, bovine viral diarrhea virus, and bovine herpes virus-1, infect the lower respiratory tract of cattle. These pathogens can co-infect cells in the respiratory system, thereby making specific treatment very difficult. Currently, the most common models for studying BRD include a submerged tissue culture (STC), where monolayers of epithelial cells are typically covered either in cellular or spent biofilm culture medium. Another model is an air-liquid interface (ALI), where epithelial cells are exposed on their apical side and allowed to differentiate. However, limited work has been reported on the study of three-dimensional (3D) bovine models that incorporate multiple cell types to represent the architecture of the respiratory tract. The roles of different defense mechanisms in an infected bovine respiratory system, such as mucin production, tight junction barriers, and the production of antimicrobial peptides in in vitro cultures require further investigation in order to provide a comprehensive understanding of the disease pathogenesis. In this report, we describe the different aspects of BRD, including the most implicated pathogens and the respiratory tract, which are important to incorporate in disease models assembled in vitro. Although current advancements of bovine respiratory cultures have led to knowledge of the disease, 3D multicellular organoids that better recapitulate the in vivo environment exhibit potential for future investigations.

Exploring major variable factors influencing flavor and microbial characteristics of upper jiupei

The flavor quality of jiupei gradually decreased with the increase of cellar height. In this study, high-throughput sequencing, metabolomics and HS-SPME-GC-MS techniques were used to explore the mechanism of flavor quality decline in upper jiupei in mud sealed cellars. The results showed the total content of flavor compounds increased from 1947.48 mg/L in top-site to 3855.51 mg/L in bottom of the cellar, and 19 differential flavor compounds were identified based on OPLS-DA, mainly including 12 esters such as ethyl hexanoate, ethyl butyrate, propyl hexanoate, hexyl caproate and 5 other substances such as caprylic acid, decanal and nonaldehyde. Lactobacillus, Prevotella and Methanobacterium were dominant genus of bacteria in all of cellars, while Thermomyces, Aspergillus, Pichia, Trichosporon and Rhizopus were the dominant genera of fungi. Oxygen was the key factor causing the quality heterogeneity of flavor substances and microbial communities in jiupei at different depths. Anaerobic micro-pressure sealed cellars (AMSC) method was developed and applied to jiupei fermentation, the difference in oxygen content between top site (5.90 ± 0.62 %) and bottom of the cellar (4.17 ± 0.75 %) in AMSC was smaller than that in mud sealed cellars, there were no significant differences in flavor substances content between top site and bottom of the cellar, and microbial communities showed no significant differences of the four-layer jiupei. This study provides a theoretical support for improving the flavor quality of upper jiupei.

Effects of SMOF on soil properties, root-zone microbial community structure, metabolites, and maize (Zea mays L.) response on a reclaimed barren mountainous land.

Maize is the largest crop produced in China. With the growing population and the rapid development of urbanization and industrialization, maize has been recently cultivated in reclaimed barren mountainous lands in Zhejiang Province, China. However, the soil is usually not suitable for cultivation because of its low pH and poor nutrient conditions. To improve soil quality for crop growth, various fertilizers, including inorganic, organic, and microbial fertilizers, were used in the field. Among them, organic fertilizer-based sheep manure greatly improved the soil quality and has been widely adopted in reclaimed barren mountainous lands. But the mechanism of action was not well clear. The field experiment (SMOF, COF, CCF and the control) was carried out on a reclaimed barren mountainous land in Dayang Village, Hangzhou City, Zhejiang Province, China. To systematically evaluate the effect of SMOF on reclaimed barren mountainous lands, soil properties, the root-zone microbial community structure, metabolites, and maize response were investigated. Compared with the control, SMOF could not significantly affect the soil pH but caused 46.10%, 28.28%, 101.94%, 56.35%, 79.07%, and 76.07% increases in the OMC, total N, available P, available K, MBC, and MBN, respectively. Based on 16S amplicon sequencing of soil bacteria, compared with the control, SMOF caused a 11.06-334.85% increase in the RA of Ohtaekwangia, Sphingomonas, unclassified_Sphingomonadaceae, and Saccharibacteria and a 11.91-38.60% reduction in the RA of Spartobacteria, Gemmatimonas, Gp4, Flavisolibacter, Subdivision3, Gp6, and unclassified_Betaproteobacteria, respectively. Moreover, based on ITS amplicon sequencing of soil fungi, SMOF also caused a 42.52-330.86% increase in the RA of Podospora, Clitopilus, Ascobolus, Mortierella, and Sordaria and a 20.98-64.46% reduction in the RA of Knufia, Fusarium, Verticillium, and Gibberella, respectively, compared with the control. RDA of microbial communities and soil properties revealed that the main variables of bacterial and fungal communities included available K, OMC, available P, MBN, and available K, pH, and MBC, respectively. In addition, LC-MS analysis indicated that 15 significant DEMs belonged to benzenoids, lipids, organoheterocyclic compounds, organic acids, phenylpropanoids, polyketides, and organic nitrogen compounds in SMOF and the control group, among which four DEMs were significantly correlated with two genera of bacteria and 10 DEMs were significantly correlated with five genera of fungi. The results revealed complicated interactions between microbes and DEMs in the soil of the maize root zone. Furthermore, the results of field experiments demonstrated that SMOF could cause a significant increase in maize ears and plant biomass. Overall, the results of this study showed that the application of SMOF not only significantly modified the physical, chemical, and biological properties of reclaimed barren mountainous land but also promoted maize growth. SMOF can be used as a good amendment for maize production in reclaimed barren mountainous lands.

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.

Structural characterization of pectic polysaccharides from Amaranth caudatus leaves and the promotion effect on hippocampal glucagon-like peptide-1 level

In this study, decolorized pectic polysaccharides (D-ACLP) with molecular weight (Mw) distribution of 3483– 2,023,656 Da were prepared from Amaranth caudatus leaves. Purified polysaccharides (P-ACLP) with the Mw of 152,955 Da were further isolated from D-ACLP through gel filtration. The structure of P-ACLP was analyzed by 1D and 2D NMR spectra. P-ACLP were identified as rhamnogalacturonan-I (RG-I) containing dimeric arabinose side chains. The main chain of P-ACLP was composed of →4)-α-GalpA-(1→, →2)-β-Rhap-(1→, →3)-β-Galp-(1→ and →6)-β-Galp-(1→. There was a branched chain of α-Araf-(1→2)-α-Araf-(1→ connected to the O-6 position of →3)-β-Galp-(1→. The GalpA residues were partially methyl esterified at O-6 and acetylated at O-3. The 28-day consecutive gavage of D-ALCP (400 mg/kg) significantly elevated the hippocampal glucagon-like peptide-1 (GLP-1) levels in rats. The concentrations of butyric acid and total short chain fatty acids in the cecum contents also increased significantly. Moreover, D-ACLP could significantly increase the gut microbiota diversity and dramatically up-regulated the abundance of Actinobacteriota (phylum) and unclassified Oscillospiraceae (genus) in intestinal bacteria. Taking together, D-ACLP might promote the hippocampal GLP-1 level through the beneficial regulation of butyric acid-producing bacteria in gut microbiota. This study contributed to making full use of Amaranth caudatus leaves for cognitive dysfunction intervention in food industry.

Metagenomic analysis of the microbial community at the Riutort oil shale mine (NE Spain): Potential applications in bioremediation and enhanced oil recovery

Preservation of the environment of the Riutort oil shale mine for more than a century has favored the presence of a paradigmatic ecosystem of oil-degrading microorganisms. After extensive sampling and analysis by 16S rRNA sequencing, a marked prokaryotic community comprising diverse groups of bacteria (genus such as Methylobacter, Thiothrix, and Desulfobacca) and archaea (e.g., Methanobrevibacter genus) with hydrocarbon-degrading activity was found. Aerobic microorganisms were predominant in several samples but facultative microorganisms were also present, and there was an interesting transition to strict anaerobic conditions in some areas. One of the samples contained oil degrading aerobic bacteria such as Pseudomonas spp. and Brevundimonas spp. Of the microbes studied, we conducted a laboratory assessment of the capacity of this specific consortium for bioremediation of petroleum-polluted soil and microbial enhanced oil recovery processes. To this end, we used oily sludge-contaminated soil from La Libertad Refinery and cores from the Ancón Field, respectively, both sites in southwestern Ecuador. The Riutort consortium degraded 50.8% of total petroleum hydrocarbons, 64.2% of saturates, 41.3% of aromatics, and 37.4% of polar compounds after a 60-day incubation using oily sludge as the sole source of carbon. The performance of this consortium reflects its notable potential for bioremediation purposes. In turn, flooding with the natural Riutort consortium and its metabolites achieved a 7.2% (v/v) incremental recovery of crude oil through a sand-pack assay. These results are comparable to those reported using synthetic bacterial consortia, and thus reveal the great interest of the study seepages, not only for understanding microbial activities in oil degradation but also their use in biotechnological applications.