Microbial Numbers Research Articles

Development and early testing of a simple, low cost, fast sensor for maternal and neonatal group B Streptococcus

Streptococcus agalactiae, (Group B Streptococcus (GBS)), is a common colonizer of the female vagina. In women giving birth it can be transmitted to the baby and cause serious illness and even death to the child. We have developed a biosensor comprising of phospholipids and fatty acids vesicles encapsulating high concentration, self-quenched carboxyfluorescein, which is released by the lysis of the vesicle by virulence factors expressed by GBS, becoming diluted and fluorescent. The microbial specificity of the sensor was tested against a number of GBS strains and other microbes including Candida albicans, Enterococcus faecalis and Staphylococcus epidermidis and a statistically significant response to GBS measured over these other microbes. To test the invivo efficacy of the biosensor, a pilot study using donated lower vaginal swabs from non-pregnant women was conducted, where 58 female adults were recruited. Participants donated two swabs, one which was used for the vesicle test and one for the ‘gold standard’, enriched culture media (ECM) test. An overall GBS carriage rate of 17.2% was measured using the ECM test. The vesicle biosensor test took 45 min to obtain a result, and showed a sensitivity of 83.3%, specificity of 85.7% and accuracy of 85.3%. The test accuracy is in line with current novel GBS identification tests, with the advantage of being rapid, easy to use, low-cost and able to be conducted by bedside during start of labour.

ANALISIS CEMARAN MIKROBIOLOGI BEBERAPA ASPEK PRODUKSI PADA PEDAGANG PENYEDIA MAKANAN DI SEKITAR KAMPUS UNIVERSITAS BUMIGORA MATARAM

Most health problems by food are caused by contamination of microorganisms. This contamination can due because cleanliness or improper implementation of sanitation and hygiene. The aim of this research is to identify microorganism contamination in the production aspects of food traders around the Campus of Bumigora University Mataram. Total microbial testing was carried out using the Total Plate Count (TPC) method for air, table, floor, equipment and water samples. Another method for testing coliforms in water use the principle of the Most Probably Number (MPN) method. The observation results show that the environmental quality as seen from the total microbes in the air is below the threshold, namely <700 col/m3, so it is said to be still safe. Meanwhile, table, floor and equipment samples showed that the total number of microbes was high enough to exceed the required threshold, especially those related to eating utensils such as plates, glasses and spoons. The total microbial test in the water sources used by the three traders showed that the two water sources used contained microbial colonies which were tested via TPC with colony numbers ranging from 87.7 – 99 x 10-5 CFU/ml. The results of the coliform estimation test using the MPN method principle showed that there was no suspicion of any coliform bacteria contamination in the two water samples, which indicated that both water sources also met the clean water requirements according to Minister of Health Regulation No. 492 of 2010.

Monitoring of microbial, water quality, and production performance of Litopenaeus vannamei on intensive pond in Bulukumba, South Sulawesi, Indonesia

The aim of the research is to monitor the dynamics of microbial number, water quality, and production performance in Pacific white shrimp (Litopenaeus vannamei) cultivation in Bulukumba, South Sulawesi Province, Indonesia, utilizing an intensive system. This research was carried out on seven Pacific white shrimp ponds over the duration of one maintenance cycle (84 days), from November 2019 to February 2020. Interestingly, the results showed that the highest total bacterial counts (TBC) were obtained in pond P3, namely in the range of 0.12-98.0×105 CFU/mL, the highest total Vibrio counts (TVC) were obtained in pond P5, namely in the range of 0.09-2.8×105 CFU/mL, luminous bacterial counts (LBC) were only found in ponds P1, P4, and P5 with the same range values, namely 0-100×103 CFU. The best performance of Pacific white shrimp production was found in pond P2, with a percentage of survival rate (SR) and productivity of 65 percent and 4074.5kg/ha, respectively, and the worst was found in pond P5, with a percentage of survival rate (SR) and productivity of 35 percent and 2583.66 kg/ha, respectively. Finally, the intense culture system used for Pacific white shrimp accumulates dynamics that may alter microbiology, water quality, and production performance.

Core gut microbes Cloacibacterium and Aeromonas associated with different gastropod species could be persistently transmitted across multiple generations

BackgroundStudies on the gut microbiota of animals have largely focused on vertebrates. The transmission modes of commensal intestinal bacteria in mammals have been well studied. However, in gastropods, the relationship between gut microbiota and hosts is still poorly understood. To gain a better understanding of the composition of gut microbes and their transmission routes in gastropods, a large-scale and long-term experiment on the dynamics and transmission modes of gut microbiota was conducted on freshwater snails.ResultsWe analyzed 244 microbial samples from the digestive tracts of freshwater gastropods and identified Proteobacteria and Bacteroidetes as dominant gut microbes. Aeromonas, Cloacibacterium, and Cetobacterium were identified as core microbes in the guts, accounting for over 50% of the total sequences. Furthermore, both core bacteria Aeromonas and Cloacibacterium, were shared among 7 gastropod species and played an important role in determining the gut microbial community types of both wild and cultured gastropods. Analysis of the gut microbiota at the population level, including wild gastropods and their offspring, indicated that a proportion of gut microbes could be consistently vertically transmitted inheritance, while the majority of the gut microbes resulted from horizontal transmission. Comparing cultured snails to their wild counterparts, we observed an increasing trend in the proportion of shared microbes and a decreasing trend in the number of unique microbes among wild gastropods and their offspring reared in a cultured environment. Core gut microbes, Aeromonas and Cloacibacterium, remained persistent and dispersed from wild snails to their offspring across multiple generations. Interestingly, under cultured environments, the gut microbiota in wild gastropods could only be maintained for up to 2 generations before converging with that of cultured snails. The difference observed in gut bacterial metabolism functions was associated with this transition. Our study also demonstrated that the gut microbial compositions in gastropods are influenced by developmental stages and revealed the presence of Aeromonas and Cloacibacterium throughout the life cycle in gastropods. Based on the dynamics of core gut microbes, it may be possible to predict the health status of gastropods during their adaptation to new environments. Additionally, gut microbial metabolic functions were found to be associated with the adaptive evolution of gastropods from wild to cultured environments.ConclusionsOur findings provide novel insights into the dynamic processes of gut microbiota colonization in gastropod mollusks and unveil the modes of microbial transmission within their guts.1dB18pPYxP-ygVgUJj2q9BVideo

Alternative Starter Fertilization Strategies in Maize (Zea mays L.) Cultivation: Agronomic Potential of Microgranular Fertilizer and Plant Growth-Promoting Microorganisms and Their Impact on the Soil Native Microbial Community

Phosphorous (P) starter fertilization can increase maize (Zea mays L.) yield. Widespread application in soils with sufficient P availability leads to environmental risks. Subsequently, alternative strategies to support the maize plant’s early development are needed to lower P surpluses. Here, we conducted field experiments comparing standard starter fertilizer diammonium phosphate (DAP) (20.1 kg P ha−1) to microgranular fertilizer (MG) (2.4 kg P ha−1) and combined in-furrow inoculation with Bacillus atrophaeus and mycorrhizal fungi (Rhizoglomus irregulare, Funneliformis mosseae, and Funneliformis caledonium), alone and in combination. The soil microbial community inside and between the maize rows was monitored by quantitative PCR (qPCR)-based quantification of eight fungal and bacterial groups. The yield did not vary between fertilization with DAP or MG and no fertilizer control. The combined microorganism inoculum (MO), however, enhanced the yield by 4.2%. The soil microbial community composition was not affected by the MO application. However, on one field site and inside the rows, it leads to a significant increase in overall microbial gene copy numbers by 9.3% and a significant decrease in the relative abundance of the bacterial phylum of Bacillota (Firmicutes) by 18%. The in-furrow MO application is thus a promising option for starter fertilizer replacement.

The mechanism effects of root exudate on microbial community of rhizosphere soil of tree, shrub, and grass in forest ecosystem under N deposition

Forests are composed of various plant species, and rhizosphere soil microbes are driven by root exudates. However, the interplay between root exudates, microbial communities in the rhizosphere soil of canopy trees, understory shrubs, grasses, and their responses to nitrogen (N) deposition remains unclear. Pinus tabulaeformis, Rosa xanthina, and Carex lancifolia were used to investigate root exudates, rhizosphere soil microbial communities, and their responses to N application in forest ecosystem. Root exudate abundances of P. tabulaeformis were significantly higher than that of R. xanthina and C. lancifolia, with carbohydrates dominating P. tabulaeformis and R. xanthina root exudates, fatty acids prevailing in C. lancifolia root exudates. Following N application, root exudate abundances of P. tabulaeformis and R. xanthina initially increased before decreasing, whereas those of C. lancifolia decreased. Microbial number of rhizosphere soil of C. lancifolia was higher than that of P. tabulaeformis and R. xanthina, but there was insignificant variation of rhizosphere soil microbial diversity among plant species. N application exerted promotional and inhibitory impacts on bacterial and fungal numbers, respectively, while bacterial and fungal diversities were increased by N application. Overall, N application had negative effects on root exudates of P. tabulaeformis, inhibiting rhizosphere soil microbial populations. N application suppressed rhizosphere soil microbial populations by increasing root exudates of R. xanthina. Conversely, N application elevated nutrient content in the rhizosphere soil of C. lancifolia, reducing root exudates and minimally promoting microbial populations. This study highlights the importance of understory vegetation in shaping soil microbial communities within forests under N deposition.

Bioactive ZnO Nanoparticles: Biosynthesis, Characterization and Potential Antimicrobial Applications.

In recent years, biosynthesized zinc oxide nanoparticles (ZnONPs) have gained tremendous attention because of their safe and non-toxic nature and distinctive biomedical applications. A diverse range of microbes (bacteria, fungi and yeast) and various parts (leaf, root, fruit, flower, peel, stem, etc.) of plants have been exploited for the facile, rapid, cost-effective and non-toxic synthesis of ZnONPs. Plant extracts, microbial biomass or culture supernatant contain various biomolecules including enzymes, amino acids, proteins, vitamins, alkaloids, flavonoids, etc., which serve as reducing, capping and stabilizing agents during the biosynthesis of ZnONPs. The biosynthesized ZnONPs are generally characterized using UV-VIS spectroscopy, TEM, SEM, EDX, XRD, FTIR, etc. Antibiotic resistance is a serious problem for global public health. Due to mutation, shifting environmental circumstances and excessive drug use, the number of multidrug-resistant pathogenic microbes is continuously rising. To solve this issue, novel, safe and effective antimicrobial agents are needed urgently. Biosynthesized ZnONPs could be novel and effective antimicrobial agents because of their safe and non-toxic nature and powerful antimicrobial characteristics. It is proven that biosynthesized ZnONPs have strong antimicrobial activity against various pathogenic microorganisms including multidrug-resistant bacteria. The possible antimicrobial mechanisms of ZnONPs are the generation of reactive oxygen species, physical interactions, disruption of the cell walls and cell membranes, damage to DNA, enzyme inactivation, protein denaturation, ribosomal destabilization and mitochondrial dysfunction. In this review, the biosynthesis of ZnONPs using microbes and plants and their characterization have been reviewed comprehensively. Also, the antimicrobial applications and mechanisms of biosynthesized ZnONPs against various pathogenic microorganisms have been highlighted.

N, P and C removal simultaneously and microbial population numbers in a cyclic activated sludge system treating village and township domestic wastewater by altering the cycle times.

It was necessary to research an efficient treatment process suitable for township domestic wastewater. In this paper, the performance of the cyclic activated sludge system (CASS) system for simultaneous carbon (C), nitrogen (N) and phosphorus (P) removal was investigated by changing the operation cycle of the CASS reactor. Four operating conditions were set up, T1, T2, T3 and T4, with cycle times of 6, 8, 12 and 8 h (with carbon source), respectively. The results showed that the CASS system had good simultaneous removal of C, N and P. The highest removal rates of COD, TN, NH4+ -N and TP were 87.69, 72.99, 98.60 and 98.38%, respectively, at a cycle time of 8 h. The TN removal rate could be increased to 82.51% after the addition of carbon source. Microbial community analysis showed that Proteobacteria, Bacteroidetes and Candidatus Saccharibacteria were the main phylum-level bacteria. Their presence facilitated the effectiveness of the CASS process for nitrogen removal and phosphorus removal. Functional analysis of genes revealed that the abundance values of genes associated with C, N and P metabolism were higher when the treatment was effective.

ANALYSIS OF COCOA FERMENTATION WITH THE ADDITION OF YEAST AND LACTIC ACID BACTERIA

Abstract One of the factors that affect the quality of cocoa beans is post-harvest handling such as the fermentation process. Fermentation plays an important role in determining the final quality of dried cocoa beans. Chocolate flavors can be produced from microbial fermentation from high-quality cocoa bean raw materials by utilizing microbes. This study aims to calculate the number of microbes at the beginning and end of the cocoa bean fermentation process, observing the pH value, temperature, and color of cocoa beans. The treatment carried out is a fermentation variation consisting of: (1) natural fermentation or without the addition of microorganisms; (2) controlled fermentation with the addition of microorganisms consisting of Saccharomyces cerevisiae, Lactic Acid Bacteria simultaneously added at the beginning of fermentation. The addition of microorganisms is 106 CFU / 1kg of cocoa beans each. Fermentation is carried out in a fermentation box with a capacity of 1 kg of fresh cocoa, at room temperature (33-35oC), for 4 days. The analysis carried out includes calculating the number of microbes at the beginning and end of fermentation, measuring pH, and organoleptic observations of the color of fermented cocoa beans. The results of the experiment can be concluded that there is an increase in the addition of mixed inoculum (Saccharomyces cerevisiae and Lactobacillus lactis) affecting the influence of chemical changes of the substrate during fermentation; the temperature value in cocoa fermentation ranges from 30 – 32 oC, the pH value in cocoa fermentation does not have a significant increase; and the color of cocoa beans from mixed inoculum fermentation is close to good with a dominant brown color against purple

Isolation and study of the species composition of rumen microorganisms in hybrid sheep

Relevance. It is known that genotypic features affect the activity of the functioning of regulatory systems, which is accompanied by changes in the intensity and direction of digestive and metabolic processes. The digestibility and use of nutrients, as well as the need for them in animals of different origins are not the same. Therefore, the study of the species composition and enzymatic properties of microorganisms in hybrid animals is of great interest. Scientific research in this area can expand the species diversity of cellulolytic microorganisms through the use of wild forms of sheep, in which the process of splitting and digesting raw fiber occurs more intensively.Methods. The species composition of the microflora and the main groups of microorganisms (total microbial number (OMH), lactic acid, enterococci, yeast-like fungi and cellulolytic microorganisms) were determined in the microbiology laboratory of the L.K. Ernst FITZ VIZH in 2021–2023 by seeding tenfold dilutions into accumulative and differential diagnostic media, followed by counting their number (CFU/ml) by groups of microorganisms.Results. According to the results of the study of the species composition of the scar content of hybrid sheep of different bloodlines, the largest number of microorganisms in the main groups was observed in hybrids — sheep 1/4 Argali × 3/4 Romanovskaya. The largest number of cellulolytic microorganisms with high enzymatic activity was isolated from four-breed hybrids: 1/32 Argali × 7/32 Romanovskaya × 8/32 Mouflon × 16/32 Katadin.

Peranan mikrobiologi dalam pengelolaan Lingkungan (Studi tentang mikro organisme di lingkungan alamiah)

Microbes are everywhere around us, some inhabiting the soil, water and atmosphere. The study of microbes in their natural environment is called microbial ecology. Ecology is a part of biology that is concerned with the study of the relationship of organisms or groups of organisms with their environment. Microbial ecology plays an important role in helping improve environmental quality. For example, microbes decompose waste from humans and industry that is thrown into it. A microorganism can grow well if the surrounding environmental conditions are very supportive. Microorganisms that grow are an increase in the number of microbes so that they can form a microbial population which can be called a colony and not cells that increase in size or length. The population of microorganisms can become very large in a relatively short period of time and the growth of microorganisms cannot be controlled. The presence of microorganisms in the environment can provide advantages and disadvantage

Analysis of activation energy and microbial activity on couple stress nanofluid with heat generation

This investigation includes the performance of the Couple Stress Nanofluid with microbial activity, activation energy incorporation of thermal conductivity, heat generation, variable viscosity and other parameters. We used some suitable similarity transformations to convert the governing partial differential equations and the initial boundary conditions of our model into the coupled structure of ordinary differential equations and final boundary conditions. Furthermore, the Spectral Quasi Linearization Method (SQLM) was used to numerically solve these ordinary differential equations with boundary conditions, generating the reassuring impacts of various parameters taken in our model. The graphical representation for the flow, temperature, solute and microbial distribution was analyzed with activation energy, heat generation and other interesting parameters. The impact of variable viscosity and thermal conductivity with the Prandtl number for the local skin friction, Nusselt, Sherwood, and the microbial density numbers was included and reflects the favorable results. The comparison table is also included to validate our model. The rising values of the activation energy parameter enhances the solute and microbe profiles, while rising of bio-convection Rayleigh number and Reynolds numbers discriminates the heat profiles, but enhances the solute profile. The microbial profile of the model falls for the rising values of the microbe reaction parameter.

Changes of atrazine dissipation and microbial community under coexistence of graphene oxide in river water

The coexistence of herbicide atrazine (ATZ) and the nanomaterial graphene oxide (GO) in natural water bodies will be an inevitable scenario due to their widespread application and consequent release into aquatic ecosystems. But the dissipation of ATZ with GO and the response of the microbial community to their combination are still not clear. Here, we investigated the dissipation dynamics and transformation of ATZ with and without GO in river water after 21-d incubation. In the presence of GO, ATZ residue significantly decreased by 11%−43%; the transformation of ATZ markedly increased by 11%−17% when ATZ concentrations were not above 1.0 mg∙L–1. The direct adsorption of ATZ on GO, mainly via π–π interactions, proton transfer and hydrogen bonding, contributed 54%−68% of the total increased ATZ dissipation by GO. ATZ and ATZ+GO exerted effects of similar magnitude on microbial OTU numbers with an increase of bacterial diversity. The coexisting GO increased the relative abundance of ATZ-degradation bacteria and Chitinophagales, thus improving ATZ transformation. This work indicated that the coexistence of GO at environmentally relevant concentrations can effectively reduce ATZ residues and promote the transformation of ATZ to degradation products in river water; nevertheless, the potential risk of GO acting as an ATZ carrier should be given more prominence.

Derangement of the infant microbiome development: what a pediatrician needs to know. A review

The research on the microbiome and microbiota of different human ecological niches and their impact on human health showed a significant breakthrough in the last decade. It is known that minor microbial contamination is present even in the fetus in utero, inducing immunological resistance. Immediately after birth, the baby rapidly becomes colonized by maternal and environmental microorganisms. The mode of delivery impacts the number of microbes and species composition and subsequent changes in the infant's immune response. A high risk of early onset of atopic march has been reported in children born by cesarean section and treated with antibacterial drugs in early life. This paper reviews the results of recent studies of the effect of the probiotic based on the two most studied strains of Lactobacillus rhamnosus GG and Bifidobacterium lactis BS01 (Probielle Baby) on intestinal microbiota development and the prospects of its use for correcting disorders in children at high risk of atopy.

Microbiological assessment of the state of urban soils of the oil and gas region on the example of the territory of Kogalym

In the course of this work, the total numbers of heterotrophic microorganisms and the numbers of microbes participating in the nitrogen cycle (ammonifying, denitrifying, nitrifying and nitrogen-fixing ones) in urban and natural (background) soils of Kogalym were estimated. A relation between the obtained results with geochemical indicators was revealed. Our microbiological analysis showed the predominance of nitrogen-fixing microorganisms in urban soils (5.0×104 – 2.0×106 CFU/g of soil), which were on average 44 less than in natural soils. In the last ones the average number of denitrifying microorganisms was 7.0×104 CFU/g of soil, exceeding 1.3 times their number in urban soils. Based on the information obtained, microbial contents in the soils of Kogalym were established as a row: nitrogen fixators > ammonifiers > heterotrophs > denitrifiers; in background samples: denitrifiers > ammonifiers > heterotrophs > nitrogen fixators. According to the data of ecological and geochemical analysis, an excess of the MPC of mobile forms of heavy metals, such as Cu, Ni and Zn, was revealed in the Eastern Industrial zone of the city. A significant inverse correlation was revealed between the number of denitrifying microorganisms in the Kogalym soil microbiocenoses and the content of mobile Ni and Cu forms, which points to a possible negative effect of these metals on the development of denitrifiers. The minimum number of ammonifying, denitrifying and nitrogen-fixing microorganisms was found in the Eastern Industrial zone, especially in the soil samples that were taken near the railway. On the whole, the absence of noticeable differences in the microorganisms` content of the studied groups in urban and natural soils indicates a low level of soil pollution in Kogalym. The obtained results represent the basis for subsequent ecological monitoring of the soils in the city and adjacent oil-producing areas, forecasting the environmental consequences of anthropogenic activities in these territories.

Comprehensive Investigation of the Influence of High-Altitude Hypoxia on Clopidogrel Metabolism and Gut Microbiota.

The amount of metabolites converted into active metabolites is correspondingly reduced since only more than 50% of clopidogrel is absorbed. Exploring the effect of gut microbiota altered by altitude hypoxia on the pre-absorption metabolism of clopidogrel. In vitro and in vivo experiments were conducted to analyze the metabolism of clopidogrel through LCMS/ MS, while 16S rRNA analysis was used to investigate the changes in the gut microbiota of high-altitude animals. We demonstrated that the intestinal flora is involved in the metabolism of clopidogrel through in vivo and in vitro experiments. In addition, the plateau environment caused changes in the number and composition of intestinal microbes. Intriguingly, alterations in the microbial population could lead to an increase in the pre-absorption metabolism of clopidogrel after rapid entry into the plateau, the amount of absorbed blood is thus reduced, which may affect the bioavailability and therapeutic effect of clopidogrel. Our results not only as a first clinical reference for dose adjustment of clopidogrel in high-altitude environments but also would be helpful to provide a statement on the broader significance within the field of pharmacokinetics or personalized medicine.

Effect of chilled storage on the quality, in-vitro protein digestibility, and microbial growth of sous vide processed beef short ribs pre-treated with pulsed electric field (PEF)

Sous vide (60 °C/24 h) processed beef short ribs pre-treated with Pulsed Electric Field (electric field strength: 0.65–0.80 kV/cm, specific energy: 87.00–102.39 kJ/kg) were stored at 4 °C for 42 days. Cooking loss, Texture Profile Analysis (TPA) parameters, colour, lipid and protein oxidation, in vitro protein digestibility and microbial growth were assessed. Storage time significantly (p < 0.05) affected TPA hardness, cohesiveness, springiness, and gumminess, but had no effect on adhesiveness and colour parameters. Lipid and protein oxidation significantly (p < 0.05) increased during storage. In vitro protein digestibility significantly (p < 0.05) decreased after 42 days of chilled storage. Aerobic and anaerobic microbial numbers were found below detection limit (102 CFU/g meat) until 21 and 42 days, respectively. The detection of bacteria after 21 days of storage was believed to be due to the germination and growth of spore forming bacterial capable of growth at 4 °C, which if present will limit the shelf life. Industrial relevanceThis information provides practical industry evidence on the shelf life of PEF-SV processed short ribs during chilled (4 °C) storage. Three-layer plastic and aluminum laminate packaging could maintain the quality and safety of the product. No microbial growth was detected up to three weeks of chilled storage. Prolonging storage time affects the texture properties of PEF-SV processed short ribs (SR) but not the meat colour.

A lesson from polybutylene succinate plastisphere to the discovery of novel plastic degrading enzyme genes in marine vibrios.

Polybutylene succinate (PBS) is an eco-friendly green plastic. However, PBS was shown as being non-biodegradable in marine environments, and up until now, only a limited number of PBS-degrading marine microbes have been discovered. We first set up in vitro PBS- and PBSA (polybutylene succinate adipate)-plastispheres to characterize novel PBS-degrading marine microbes. Microbial growth and oxygen consumption were observed in both PBS- and PBSA-plastispheres enriched with natural seawater collected from Usujiri, Hokkaido, Japan, and Vibrionaceae and Pseudoalteromonadaceae were significantly enriched on these films. Further gene identification indicated that vibrios belonging to the Gazogenes clade possess genes related to a PBS degrading enzyme (PBSase). The PBS degradation assay for six Gazogenes clade vibrios identified Vibrio ruber, Vibrio rhizosphaerae, and Vibrio spartinae as being capable of degrading PBS. We further identified the gene responsible for PBSase from the type strain of V. ruber, and the purified recombinant vibrio PBSase was found to have low-temperature adaptation and was active under high NaCl concentrations. We also provided docking models between the vibrio PBSase and PBS and PBSA units to show how vibrio PBSase interacts with each substrate compared to the Acidovorax PBSase. These results could contribute to a more sustainable society through further utilization of PBS in marine environments and plastic recycling.

Select symbionts drive high IgA levels in the mouse intestine

Immunoglobulin A (IgA) is an important factor in maintaining homeostasis at mucosal surfaces, yet luminal IgA levels vary widely. Total IgA levels are thought to be driven by individual immune responses to specific microbes. Here, we found that the prebiotic, pectin oligosaccharide (pec-oligo), induced high IgA levels in the small intestine in a Tcell-dependent manner. Surprisingly, this IgA-high phenotype was retained after cessation of pec-oligo treatment, and microbiome transmission either horizontally or vertically was sufficient to retain high IgA levels in the absence of pec-oligo. Interestingly, the bacterial taxa enriched in the overall pec-oligo bacterial community differed from IgA-coated microbes in this same community. Rather, a group of ethanol-resistant microbes, highly enriched for Lachnospiraceae bacterium A2, drove the IgA-high phenotype. These findings support a model of intestinal adaptive immunity in which a limited number of microbes can promote durable changes in IgA directed to many symbionts.

Metagenomic characterization of the cecal microbiota community and functions in finishing pigs fed fermented Boehmeria nivea.

Ramie (Boehmeria nivea, BN) is used as livestock forage through suitable silage fermentation owing to its nutritional value. To date, relatively few studies have investigated the effects of dietary fermented BN (FBN) on gut health in finishing pigs. The aim of the present study was to investigate the effects of dietary supplementation with 20% FBN on intestinal morphology, gene expression, and the functional response of the gut microbiota in finishing pigs. We found that FBN did not significantly affect serum antioxidant enzyme activities, ileal morphology, or the expression of genes encoding antioxidant enzymes, inflammatory cytokines, or tight junction proteins in the liver of the pigs. However, the gene expression levels of aryl hydrocarbon receptor (AHR) and interleukin 6 (IL6) were significantly downregulated in the ileum. A metagenomic analysis demonstrated that, compared with that seen in the control group, the cecal microbiota of pigs in the FBN treatment group was more closely clustered and contained a greater number of unique microbes. Bacteria were the predominant kingdom in the cecal microbiota, while Firmicutes, Bacteroidetes, and Proteobacteria were the dominant phyla, and Streptococcus, Lactobacillus, and Prevotella were the dominant genera. Dietary FBN significantly increased the abundance of the probiotic bacterium Roseburia inulinivorans (p < 0.05). Functional analysis of the cecal microbiota showed that ABC transporter levels and glycolysis/gluconeogenesis-associated functions were diminished in FBN-fed pigs. Meanwhile, CAZyme analysis revealed that dietary FBN significantly downregulated the contents of carbohydrate-active enzymes, such as GT2, GH1, GH25, and GH13_31. In addition, cytochrome P450 analysis revealed that the abundance of CYP51 and CYP512 decreased with FBN treatment. An assessment of antibiotic resistance based on the Comprehensive Antibiotic Resistance Database (CARD) annotation indicated that the cecal microbes from pigs in the FBN treatment group had increased resistance to lincosamide, streptogramin, and chloramphenicol and reduced resistance to amikacin, isepamicin, neomycin, lividomycin, gentamicin, paromomycin, ribostamycin, and butirosin. Finally, virulence factor-related analysis showed that putative hemolysin-associated functions were decreased, whereas fibronectin-binding protein, flagella, and alginate-associated functions were increased. Taken together, our data showed that FBN supplementation exerted only minor effects on intestinal morphology and microbial community composition, suggesting that it is potentially safe for use as a supplement in the diets of finishing pigs. However, more studies are needed to validate its functionality.