Composition Of Microorganisms Research Articles

The antimicrobial peptide Abaecin alleviates colitis in mice by regulating inflammatory signaling pathways and intestinal microbial composition

Abaecin is a natural antimicrobial peptide (AMP) rich in proline from bees. It is an important part of the innate humoral immunity of bees and has broad-spectrum antibacterial ability. This study aimed to determine the effect of Abaecin on dextran sulfate sodium (DSS) -induced ulcerative colitis (UC) in mice and to explore its related mechanisms. Twenty-four mice with similar body weight were randomly divided into 4 groups. 2.5% DSS was added to drinking water to induce colitis in mice. Abaecin and PBS were administered rectally on the third, fifth, and seventh days of the experimental period. The results showed that Abaecin significantly alleviated histological damage and intestinal mucosal barrier damage caused by colitis in mice, reduced the concentration of pro-inflammatory cytokines IL-1β, IL-6, TNF-α, IFN-γ, and the phosphorylation of NF-κB / MAPK inflammatory signaling pathway proteins, and improved the composition of intestinal microorganisms. These findings suggest that Abaecin may have potential prospects for the treatment of UC.

The Microbial Diversity on the Surface of Smear-Ripened Cheeses and Its Impact on Cheese Quality and Safety.

Smear-ripened cheeses are characterized by a viscous, red-orange surface smear on their rind. It is the complex surface microbiota on the cheese rind that is responsible for the characteristic appearance of this cheese type, but also for the wide range of flavors and textures of the many varieties of smear-ripened cheeses. The surface smear microbiota also represents an important line of defense against the colonization with undesirable microorganisms through various types of interaction, such as competitive exclusion or production of antimicrobial substances. Predominant members of the surface smear microbiota are salt-tolerant yeast and bacteria of the phyla Actinobacteria, Firmicutes, and Proteobacteria. In the past, classical culture-based approaches already shed light on the composition and succession of microorganisms and their individual contribution to the typicity of this cheese type. However, during the last decade, the introduction and application of novel molecular approaches with high-resolution power provided further in-depth analysis and, thus, a much more detailed view of the composition, structure, and diversity of the cheese smear microbiota. This led to abundant novel knowledge, such as the identification of so far unknown community members. Hence, this review is summarizing the current knowledge of the diversity of the surface smear microbiota and its contribution to the quality and safety of smear-ripened cheese. If the succession or composition of the surface-smear microbiota is disturbed, cheese smear defects might occur, which may promote food safety issues. Hence, the discussion of cheese smear defects in the context of an increased understanding of the intricate surface smear ecosystem in this review may not only help in troubleshooting and quality control but also paves the way for innovations that can lead to safer, more consistent, and higher-quality smear-ripened cheeses.

Identification and structural characterization of key prebiotic fraction of soluble dietary fiber from grapefruit peel sponge layer and its regulation effect on gut microbiota

In this study, the key prebiotic fraction of grapefruit peel sponge layer soluble dietary fiber (GSLSDF) was identified, and its structure characteristics and modulatory effect on intestinal microorganisms were investigated. Firstly, two fractions (GSLSDF-1 and GSLSDF-2) were isolated from GSLSDF, and the GSLSDF-1 showed a better prebiotic activity. Subsequently, GSLSDF-1 was found to have a low molecular weight and crystallinity, a loose and porous microstructure, and a high glucose content. Meanwhile, GSLSDF-1 was a dextran with a main chain linked by β-1, 4 glycosidic bonds and branched by a β-1, 6 glycosidic bonds. These structural characteristics were responsible for the favorable prebiotic activity of GSLSDF-1. Finally, the regulation effect of GSLSDF-1 on gut microbiota was analyzed in vitro fecal fermentation. Compared with the blank and GSLSDF groups, GSLSDF-1 could increase the relative abundances of Lactobacillus, Bacteroides, Bifidobacterium and Faecalibacterium coupled with decrease the relative abundances of Clostridium and Clostridioides. Furthermore, GSLSDF-1 promoted the production of short-chain fatty acids (SCFAs) by modulating the SCFAs synthesis pathway of intestinal microorganisms, while the NH3-N synthesis of intestinal microorganisms was inhibited by GSLSDF-1. Above results indicated that GSLSDF-1 was the key prebiotic fraction of GSLSDF, which could effectively optimize the intestinal microorganism composition.

Nitrogen enrichment stimulates rhizosphere multi-element cycling genes via mediating plant biomass and root exudates

Global nitrogen (N) deposition has a significant impact on the structure and function of above-ground plant communities; however, the impact of N enrichment on below-ground microbial communities remains insufficiently elucidated, especially regarding the functional gene structure. An 18-month pot experiment was conducted to examine the effects of N addition rate (0, 5, 10, and 15 g N m−2 yr−1) on the functional gene composition of rhizosphere microorganisms of Bothriochloa ischaemum, a native grass species of the semiarid area, and to evaluate the soil and plant variables connected with the observed variation. Using microarray GeoChip analysis, 2676, 744, 308, and 515 gene probes involved in carbon (C), N, phosphorus (P) and sulfur (S) cycling, respectively, were detected. Compared with the weak response of genes in the bulk soil, N addition significantly increased the abundance of genes involved in C fixation (tkta, rubisco, TIM), C degradation (amyA, ara, chitinase), methanogenesis (mcra), N2-fixation (nifH), denitrification (narG, nirK/S, nosZ), polyphosphate degradation (ppx), and sulfite reduction (dsrA, dsrB, cysJ) in the rhizosphere. The abundance of genes responsible for C-, N-, P-, and S-cycling increased with the N addition rate and was mainly regulated by variations in plant biomass and root exudates. The quantity of soil dissolved organic C played a crucial role in determining the abundance of genes related to the cycling of C, N, P, and S. Plant biomass indirectly affected gene abundance by increasing organic acids in root exudates and dissolved organic C. These findings facilitate our understanding of microbial function to elevated N levels and highlight the key role of root exudates and plant biomass in regulating microbial functions under future N-enrichment scenarios.

Research Progress for Probiotics Regulating Intestinal Flora to Improve Functional Dyspepsia: A Review.

Functional dyspepsia (FD) is a common functional gastrointestinal disorder. The pathophysiology remains poorly understood; however, alterations in the small intestinal microbiome have been observed. Current treatments for FD with drugs are limited, and there are certain safety problems. A class of active probiotic bacteria can control gastrointestinal homeostasis, nutritional digestion and absorption, and the energy balance when taken in certain dosages. Probiotics play many roles in maintaining intestinal microecological balance, improving the intestinal barrier function, and regulating the immune response. The presence and composition of intestinal microorganisms play a vital role in the onset and progression of FD and serve as a critical factor for both regulation and potential intervention regarding the management of this condition. Thus, there are potential advantages to alleviating FD by regulating the intestinal flora using probiotics, targeting intestinal microorganisms. This review summarizes the research progress of probiotics regarding improving FD by regulating intestinal flora and provides a reference basis for probiotics to improve FD.

Effect of the Combination of Clostridium butyricum and Mycelium of Phellinus igniarius on Intestinal Microbiota and Serum Metabolites in DSS-Induced Colitis.

Clostridium butyricum (CB) and Phellinus igniarius (PI) have anti-inflammatory, immune regulation, anti-tumor, and other functions. This study aimed to explore the therapeutic effect of CB and mycelium of PI (MPI) alone and in combination on colitis mice induced by dextran sodium sulfate (DSS). Mice were randomly assigned to five groups: (1) control (CTRL), (2) DSS, (3) CB, (4) MPI, and (5) CB + MPI (CON). The weight of the mice was recorded daily during the experiment, and the length of the colon was measured on the last day of the experiment. The colons were collected for hematoxylin and eosin staining, colon contents were collected for intestinal flora analysis, and serum was collected for metabolite analysis. The results showed that compared with the DSS group, CB, MPI, and CON treatments inhibited the weight loss and colon length shortening caused by DSS, significantly increased the concentrations of interleukin (IL)-4, IL-10, and superoxide dismutase, and significantly decreased the concentrations of IL-6, tumor necrosis factor-α, and myeloperoxidase. Gene sequence analysis of 16S rRNA showed that CB, MPI, and CON treatments changed the composition and structure of intestinal microorganisms. Metabolome results showed that CB, MPI, and CON treatments changed serum metabolites in DSS-treated mice, including dodecenoylcarnitine, L-urobilinogen, and citric acid. In conclusion, CB, MPI, and CON treatments alleviated DSS-induced colitis in mice by regulating intestinal flora and metabolites, with the CON group having the best effect.

МІКРОФЛОРА БОРОШНА ЯК СТАРТЕР ПРОЦЕСІВ БРОДІННЯ У ХАРЧОВИХ ТЕХНОЛОГІЯХ

The study of microorganisms used in the food industry is necessary to improve the quality of food products. The complex nature of the relationships between members of associations of these microorganisms and the influence of endogenous factors on them should be taken into account in the production of appropriate food products.The impact of endogenous factors on microorganisms used in the food industry determines the composition of their as-sociations, which in turn determines the quality of the resulting product. Therefore, analysis of the formation of such associa-tions is a necessary element of food technology.An analysis of studies andpublications has shown that today the issues related to the formation of microorganism associa-tions used to ensure fermentation processes in food technology have been given insufficient attention in the scientific literature.The purpose of the article isto study the formation of the component composition of lactic acid bacteria and yeasts of different starter cultures depending on the endogenous factors for the differentiation of fermentation products.The formation of microorganism associations in different starter cultures has been studied. In order to conduct research, different types of starter cultures were used to prepare rye-wheat bread, beer, and fermented milk products. The taxonomic com-position of the associations of the studied starter cultureswas analyzed. Endogenous factors that are the main cause of differences in the composition of microorganism associations in different starter cultures have been studied. The significance of the synergism between lactic acid bacteria and yeast for the inhibition of bacteria harmful in food production has been determined.It has been shown that the formation of the composition of microorganisms, first of all, depends on the technology of the starter preparation, its type and the chemical composition of the fermentation substrate. The organoleptic characteristics of the resulting food products were corresponded to the composition of the association of microorganisms of the starter culture thatwas used. The results obtained show that flour starters can be usedto start the fermentation process of sugar-rich substrates

Comparison of Community Composition and Function of Particle-associated Microorganisms and Free-living Microorganisms in the Mariana Trench

Comparison of Community Composition and Function of Particle-associated Microorganisms and Free-living Microorganisms in the Mariana Trench

Celiac disease and human gut microbiota – how can we study the composition of microorganisms?

Celiac disease and human gut microbiota – how can we study the composition of microorganisms?

Analysis of the quantitative composition of the dental biofilm depending on the state of the hard dental tissues

The microflora of the oral cavity affects not only the development and course of the pathology of the hard dental tissues but also the effectiveness of its treatment and prevention. Therefore, it is equally important for a dentist to determine the species composition of microorganisms and their quantitative characteristics. The aim of the work was to study the quantitative composition of the planktonic form of the dental biofilm of the vestibular surface of the cervical teeth in young patients; its analysis in patients with a wedge-shaped defect, cervical caries and clinically intact teeth. A microbiological study of the dental biofilm of intact premolars of 33 caries-resistant patients (average age [23.90±5.34] years) was conducted. All patients were divided into three groups depending on the condition of the hard dental tissues. The dental biofilm removed from the lesion was additionally examined in patients with wedge-shaped defects. Microorganisms were identified by morphological, tinctorial and biochemical characteristics. A quantitative study of the population level was carried out by counting colony-forming units (CFU) in one gram of biomaterial which was expressed as a decimal logarithm (lg CFU/g). An imbalance between representatives of pathological and normal microflora was determined. Patients with cervical caries had a significantly higher chance of having Str. mutans and Lactobacterium in the dental biofilm, and a lower chance Str. γ-haemolyticus (p<0.05). It confirms the role of Str. mutans and Lactobacterium in the etiology of cervical dental caries. There were no significant differences between the quantitative composition of the dental biofilm of patients of different groups that is probably related to the study of its planktonic component, the criteria for forming groups and the high level of caries resistance of the examined enamel. The obtained results can be useful in prescribing treatment and preventive measures for patients with cervical pathology of the teeth as well as in evaluating their effectiveness. In our opinion, it will contribute to a significant reduction in its prevalence and intensity among young people. Keywords: microorganisms, оral cavity, wedge-shaped defect, cervical caries.

Traceability of Geographic Origin Using Human Skin and Oral Microbiota.

To explore the possibility of using human skin and oral microorganisms to estimate the geographic origin of an individual through the sequencing analysis of bacterial 16S rRNA gene. Microbial DNA was extracted from the palm and oral microorganisms of the Han population in Shanghai and Chifeng, Inner Mongolia, and the composition and diversity of the microbiota were analyzed by full-length 16S rRNA gene sequencing. Then, differential species were screened and a geographic location prediction model was constructed. The compositions of palm and oral microorganisms between Shanghai and Chifeng samples were both different. The abundance and uniformity of palm side skin microorganisms were higher in Chifeng samples than in Shanghai samples, while there was no significant difference in oral microorganisms. Permutational multivariate analysis of variance (PERMANOVA) confirmed that the β-diversity between the samples from the two places were statistically significant, and the coefficients of determination (R2) for skin and oral samples were 0.129 and 0.102, respectively. Through principal co-ordinates analysis (PCoA), the samples from the two places could be preliminarily distinguished. The predictive model had the accuracies of 0.90 and 0.83 for the geographic origin using the skin and oral samples, respectively. There are differences in the compositions of palm and oral microbiota between Han populations in Shanghai and Chifeng. The prediction model constructed by the random forest algorithm can trace the unknown individuals from the above two places.

Effects of Alpinia officinarum stems and leaves extract on growth performance, non-specific immunity, and intestinal microflora of Litopenaeus vannamei

This study was to investigate the effects of Alpinia officinarum Hance stems and leaves extract (AOE) on the growth, non-specific immunity, intestinal microflora of shrimp (Litopenaeus vannamei). A total of 540 juvenile L. vannamei (2.69 ± 0.03 g) were randomly divided into six groups, and feed experiment with diet supplement of 0 g/kg (CG), 0.1 g/kg (AO-1), 0.2 g/kg (AO-2), 0.3 g/kg (AO-3), 0.5 g/kg (AO-4) and 0.7 g/kg(AO-5) AOE was carried out for 8 weeks, respectively. Compared with the control group (CG), the WGR and SGR of the AO-1, AO-3, and AO-4 groups were significantly increased. Crude protein content in the muscle of L. vannamei in AO-2 was significantly increased, while the water content was significantly decreased. The crude lipid content of each extract group was significantly decreased. Compared with the control group, activities of GSH-Px, SOD, and T-AOC in the cell-free hemolymph of AO-3 group were significantly enhanced, and the MDA content of each extract group was significantly decreased. Activities of CAT, SOD, and T-AOC in the hepatopancreas of AO-2 group were significantly increased. Gene expression levels of lvcat, lvgsh-px, and lvmn-sod in AO-3 group were obviously higher than those in the control group, while lvpropo expression was dramatically higher in AO-2 and AO-3 groups. Moreover, AOE addition in feed changed the composition and species abundance of intestinal microflora of L. vannamei at phylum and genus levels. Through α diversity analysis, the biodiversity of the flora was improved, while β diversity analysis changed the similarity of the flora between the control and addition groups. Therefore, addition of 0.2–0.3 g/kg AOE could improve the growth, immunity and optimize the composition of intestinal microorganisms of L. vannamei.

Distinct microbial communities degrade cellulose diacetate bioplastics in the coastal ocean.

Cellulose diacetate (CDA) is a promising alternative to conventional plastics due to its versatility in manufacturing and low environmental persistence. Previously, our group demonstrated that CDA is susceptible to biodegradation in the ocean on timescales of months. In this study, we report the composition of microorganisms driving CDA degradation in the coastal ocean. We found that the coastal ocean harbors distinct bacterial taxa implicated in CDA degradation and these taxa have not been previously identified in prior CDA degradation studies, indicating an unexplored diversity of CDA-degrading bacteria in the ocean. Moreover, the shape of the plastic article (e.g., a fabric, film, or foam) and plasticizer in the plastic matrix selected for different microbial communities. Our findings pave the way for future studies to identify the specific species and enzymes that drive CDA degradation in the marine environment, ultimately yielding a more predictive understanding of CDA biodegradation across space and time.

Metagenomic Sequencing Revealed Differences in the Composition of Cecal Microbes in Different Breeds of Chickens.

Intestinal microorganisms are closely related to the health, development, and production performance of animals and can also provide basic information for us to fully understand and explore the germplasm characteristics and traits of local chicken breeds. In this experiment, we used five local Chinese chicken breeds as research materials; metagenomic sequencing technology was used to explore the differences in the composition of intestinal microorganisms in different breeds, and it was found that each local chicken breed had unique unigenes, of which Silkies had the most, with a total of 12,948. GO and KEGG analyses found that the biological processes most enriched by differential functional genes include genetic coding, macromolecular transport, protein synthesis, and molecular functions such as glycoprotein binding, protein hydrolysis, etc. Each breed is enriched with specific pathways, such as Anyi tile-like gray chickens, which are enriched with pathways related to disease resistance, while Gamecocks' enrichment is related to amino acid metabolism. Random Forest and LEfSe analyses revealed specific species of intestinal microorganisms in the cecum of different breeds, such as Exiguobacterium, which is associated with melanin deposition in Silkies. Therefore, we infer that gut microorganisms are closely related to the formation of chicken breed characteristics, and the results of this experiment can provide a theoretical basis for the discovery of high-quality traits and the improvement of feeding conditions in the future.

Mechanisms of microbial-driven changes in soil ecological stoichiometry around gold mines

In this study, we used soils with different pollution and nutrient levels (non-polluted S1, highly polluted low-nutrient S2, and highly polluted high nutrient S3) around the gold mine tailing ponds, and combined with metabolic limitation modeling and macro-genomics approaches, aiming to investigate the relationship between soil microbial composition and soil eco-chemometrics characteristics under heavy metal stress. The results showed that heavy pollution resulted in reduced SOC, TN, microbial biomass, and with C- and P- acquisition (BG, CBH, ALP) as well as nitrogen limitation of soil microbial metabolism in soils (S2, S3). Further analysis by macrogenomics showed that heavy metal contamination led to an increase in α-microbial diversity and altered the composition of microbial communities in the soil. The cycling of C, N, and P nutrients was altered by affecting the relative abundance of Anaeromyxobacter, Steroidobacter, Bradyrhizobium, Acidobacterium, Limnochorda (predominantly in the Ascomycetes and Acidobacteria phyla), with the most pronounced effect on the composition of microorganisms synthesizing C-acquiring enzymes, and heavy metals and pH were the main influences on ecological stoichiometry. The results of this study are useful for understanding the sustainability of ecological remediation in heavy metal contaminated areas and for developing ecological restoration strategies.

Germination of pecan seeds changes the microbial community.

Endophytes are core of the plant-associated microbiome, and seed endophytes are closely related to the plant growth and development. Seed germination is an important part of pecan's life activities, but the composition and changes of microbes during different germination processes have not yet been revealed in pecan seeds. In order to deeply explore the characteristics of endophytes during the germination process of pecan, high-throughput sequencing was performed on seeds at four different germination stages. Findings of present study was found that the diversity and composition of microorganisms were different in different germination stages, and the microbial richness and diversity were highest in the seed endocarp break stage. It was speculated that the change of endophytes in pecan seeds was related to the germination stage. By evaluating the relationship between microbial communities, the core microbiota Cyanobacteria, Proteobacteria and Actinobacteria (bacterial) and Anthophyta and Ascomycota (fungal) core microbiota were identified in germinating pecan seeds. Finally, biomarkers in different germination processes of pecan seeds were identified by LEfSe analysis, among which Proteobacteria, Gamma proteobacteria and, Cyanobacteria and Ascomycota and Sordariomycetes were most abundant. Thus, this study will help to explore the interaction mechanism between pecan seeds and endophytes in different germination processes, and provide materials for the research and development of pecan seed endophytes.

Ethyl acetate extract of Terminalia chebula alleviates DSS-induced ulcerative colitis in C57BL/6 mice.

Background: The Chinese pharmacopeia records Terminalia chebula as effective in treating prolonged diarrhea and dysentery, blood in the stool, and prolapse. Modern pharmacological research proves it has multiple pharmacological benefits, including antioxidant, anti-inflammatory, analgesic, hepatoprotective, neuroprotective, and other properties. Objectives: This study aims to clarify the role of Terminalia chebula's ethyl acetate extract (TCEA) on ulcerative colitis (UC) induced by dextran sodium sulfate (DSS) in mice, as well as explore the potential mechanism of action. Materials and methods: The variation of different extracts of T. chebula was detected using the HPLC technique, and the main components in TCEA were identified. DSS was used to establish a mouse model to mimic the physiological state of UC in humans; the alleviating effect of TCEA and positive control 5-ASA on UC mice were evaluated by gavage treatment. Disease progression was assessed by monitoring the mouse's weight change and disease activity index (DAI). The changes in colon tissue were estimated by measuring colon length, HE, and AB-PAS staining and detecting oxidative stress parameters. The results draw from Western blot and real-time PCR showed the TLR4/MyD88/NF-κB pathway may involve in the anti-inflammatory activity of TCEA. Furthermore, the gut flora sequencing technique was employed to monitor the differentiation of intestinal microbiota of mice induced by DSS and TCEA treatment. Results: TCEA significantly lowered DAI scores and inhibited the weight loss and colonic shortening induced by DSS. The colon histomorphology and oxidative stress levels were enhanced after TCEA treatment compared with DSS induced UC group. TCEA attenuated the inflammatory response by regulating TLR4/MyD88/NF-κB pathway activation. Intestinal flora sequencing showed that DSS and TCEA greatly impacted mice's composition and diversity of intestinal microorganisms. But TCEA increased the abundance of Bacteroidetes and decreased the abundance of Firmicutes and Proteobacteria compared with the DSS group, which contributed a lot to returning the intestinal flora to a balanced state. Conclusion: This study confirms the alleviating effect of TCEA on UC and provides new ideas for developing TCEA into a new drug to treat UC.

PVDF Nanofiber Modified with ZnO Nanowires/Polydopamine for the Treatment of Sewage Containing Heavy Metals, Organic Dyes, and Bacteria.

In various countries worldwide, the issue of wastewater contamination poses a significant threat due to its intricate composition of heavy metals, organic dyes, and microorganisms, thereby complicating the purification process. Consequently, researchers have expressed considerable interest in materials capable of eliminating organic, heavy metal, and microbial pollutants. This study focuses on the fabrication of a water purification membrane (PDA/ZnO-NWs/PVDF) with a hierarchical structure and the ability to remove multiple pollutants. The membrane was created by modifying poly(vinylidene fluoride) (PVDF) nanofiber with zinc oxide nanowires (ZnO-NWs) and reinforcing it with polydopamine (PDA). The experimental results demonstrate that the PDA/ZnO-NWs/PVDF membrane exhibits a range of functionalities, including long-lasting superhydrophilicity, Cu(II) adsorption, photocatalytic degradation, and antibacterial ability. The manipulation of the DA synthesis procedure allows for the adjustment of the wettability, adsorption, and photocatalytic and antibacterial activities of the PDA/ZnO-NWs/PVDF composite. According to the Langmuir isotherm, the maximum Cu(II) adsorption capacity of the PDA/ZnO-NWs/PVDF membrane is determined to be 65.75 mg/g, which is significantly higher (27.26 mg/g) than that of the ZnO-NWs/PVDF membrane (38.49 mg/g). The PDA/ZnO-NWs/PVDF composite exhibited a notable degradation capacity toward rhodamine B under natural sunlight, reaching a maximum of 5.97 mg/g. Additionally, the degradation rate achieved during daylight hours was as high as 90.42%. Furthermore, the antibacterial efficacy of the PDA/ZnO-NWs/PVDF composite against both Gram-positive and Gram-negative bacteria approached 100%. This work presents a promising approach for the treatment of wastewater containing various coexisting contaminants.

Differential microbial composition in parasitic vs. questing ticks based on 16S next-generation sequencing.

As tick-borne diseases rise to become the second most prevalent arthropod-transmitted disease globally, the increasing investigations focus on ticks correspondingly. Factors contributed to this increase include anthropogenic influences, changes in vertebrate faunal composition, social-recreational shifts, and climatic variation. Employing the 16S gene sequence method in next-generation sequencing (NGS) allows comprehensive pathogen identification in samples, facilitating the development of refined approaches to tick research omnidirectionally. In our survey, we compared the microbial richness and biological diversity of ticks in Wuwei City, Gansu province, differentiating between questing ticks found in grass and parasitic ticks collected from sheep based on 16S NGS method. The results show Rickettsia, Coxiella, and Francisella were detected in all 50 Dermacentor nuttalli samples, suggesting that the co-infection may be linked to specific symbiotic bacteria in ticks. Our findings reveal significant differences in the composition and diversity of microorganisms, with the Friedmanniella and Bordetella genera existing more prevalent in parasitic ticks than in questing ticks (p < 0.05). Additionally, the network analysis demonstrates that the interactions among bacterial genera can be either promotive or inhibitive in ticks exhibiting different lifestyles with the correlation index |r| > 0.6. For instance, Francisella restrains the development of 10 other bacteria in parasitic ticks, whereas Phyllobacterium and Arthrobacter enhance colonization across all tick species. By leveraging NGS techniques, our study reveals a high degree of species and phylogenetic diversity within the tick microbiome. It further highlights the potential to investigate the interplay between bacterial genera in both parasitic and questing ticks residing in identical habitat environments.

Root-knot nematode infections and soil characteristics significantly affected microbial community composition and assembly of tobacco soil microbiota: a large-scale comparison in tobacco-growing areas.

Tobacco root-knot nematode (RKN) is a highly destructive soil-borne disease worldwide. However, there is a lack of research on the relationship between RKN and tobacco root microbial community composition under large-scale geographical conditions in China. In this study, we collected 65 samples from 28 main tobacco-growing areas across 10 provinces in China and conducted 16S rDNA sequencing to investigate the dynamic microbial changes in tobacco soil infected by RKN compared to healthy tobacco soil. Based on the analysis of rhizosphere soil bacterial communities, changes after RKN infection, and soil environmental factors. We found the 28 tobacco-growing areas could be divided into two distinct groups with different microbial compositions and varying responses to RKN infection. In group1 of the provinces of Anhui, Henan, Shanxi, and Heilongjiang, Vicinamibacteria dominated the bacterial community, while Acidobacteriae was present in low abundance. In contrast, group2 of the other six provinces (Yunnan, Guizhou, Chongqing, Guangxi, Hubei, and Shandong) exhibited an opposite pattern. After infected by RKN, the genera Chitinophaga increased significant in group 1, while the genera Rhodococcus in group 2 exhibited a substantial increase. Alpha-diversity analysis revealed that RKN-infected tobacco exhibited a richer and more diverse rhizosphere soil bacterial community compared to healthy tobacco in most growing areas. A total of 12 kinds of soil environmental factors were measured in healthy and RKN-infected tobacco soil, and based on the co-occurrence and correlation analysis between environmental factors and microbial species, the pH level, calcium (Ca), magnesium (Mg), phosphorus (P), iron (Fe), and sodium (Na) were identified as key environmental factors influencing the population composition of rhizosphere microorganisms during RKN infection. We observed that RKN infection further increased the pH in weakly alkaline group 1 soil, while weakly acidic group 2 soil experienced a further decrease in pH. Furthermore, we identified three genera as potential biocontrol or plant growth-promoting bacteria for tobacco. These findings provide valuable reference data for managing RKN disease in different tobacco-growing areas and contribute to the exploration of new and effective biological control methods.