Learning lifespan brain anatomical correspondence via cortical developmental continuity transfer.

Identifying anatomical correspondences in the human brain throughout the lifespan is an essential prerequisite for studying brain development and aging. But given the tremendous individual variability in cortical folding patterns, the heterogeneity of different neurodevelopmental stages, and the scarce of neuroimaging data, it is difficult to infer reliable lifespan anatomical correspondence at finer scales. To solve this problem, in this work, we take the advantage of the developmental continuity of the cerebral cortex and propose a novel transfer learning strategy: the model is trained from scratch using the age group with the largest sample size, and then is transferred and adapted to the other groups following the cortical developmental trajectory. A novel loss function is designed to ensure that during the transfer process the common patterns will be extracted and preserved, while the group-specific new patterns will be captured. The proposed framework was evaluated using multiple datasets covering four lifespan age groups with 1,000+ brains (from 34 gestational weeks to young adult). Our experimental results show that: 1) the proposed transfer strategy can dramatically improve the model performance on populations (e.g., early neurodevelopment) with very limited number of training samples; and 2) with the transfer learning we are able to robustly infer the complicated many-to-many anatomical correspondences among different brains at different neurodevelopmental stages. (Code will be released soon: https://github.com/qidianzl/CDC-transfer).

Attitudes and preferences towards erectile dysfunction treatment among men with fertility needs: insights from a clinical study.

Erectile dysfunction (ED) is prevalent among males experiencing fertility challenges, yet attitudes towards actively treating ED in this group are under-researched. From a cohort of 1256 men with reproductive needs, 303 were identified with ED. The survey encompassed 296 respondents who correctly completed the second questionnaire, revealing that 50.3% sought ED treatment, with higher ED severity increasing the likelihood of seeking treatment. Infertile men were more likely to seek treatment than those with pregnancy loss (OR 3.18, 95% CI 1.74-5.83). Men with normal semen parameters were more open to ED therapy (OR 3.02, 95% CI 1.69-5.36), whereas those undergoing Assisted Reproduction Treatment were less inclined (OR 0.32, 95% CI 0.18-0.58). PDE-5 inhibitors (PDE-5Is) were preferred by 51.0% of those seeking treatment, with 29.7% of men with pregnancy loss and 60.1% of infertile men choosing PDE-5Is as their first option. Concerns included potential adverse effects of PDE-5Is on fetal health (78.7% of men with pregnancy loss) and on sperm quality (44.2% of infertile men). In conclusion, the different fertility requirements, semen parameters, and whether received ART are significant factors influencing the acceptance of treatment, PDE-5Is utilization among individuals in men with couple pregnancy loss is notably limited.

Efficient CRISPR-mediated C-to-T base editing in Komagataella phaffii.

The nonconventional methylotrophic yeast Komagataella phaffii is widely applied in the production of industrial enzymes, pharmaceutical proteins, and various high-value chemicals. The development of robust and versatile genome editing tools for K. phaffii is crucial for the design of increasingly advanced cell factories. Here, we first developed a base editing method for K. phaffii based on the CRISPR-nCas9 system. We engineered 24 different base editor constructs, using a variety of promoters and cytidine deaminases (CDAs). The optimal base editor (PAOX2*-KpA3A-nCas9-KpUGI-DAS1TT) comprised a truncated AOX2 promoter (PAOX2*), a K. phaffii codon-optimized human APOBEC3A CDA (KpA3A), human codon-optimized nCas9 (D10A), and a K. phaffii codon-optimized uracil glycosylase inhibitor (KpUGI). This optimal base editor efficiently performed C-to-T editing in K. phaffii, with single-, double-, and triple-locus editing efficiencies of up to 96.0%, 65.0%, and 5.0%, respectively, within a 7-nucleotide window from C-18 to C-12. To expand the targetable genomic region, we also replaced nCas9 in the optimal base editor with nSpG and nSpRy, and achieved 50.0%-60.0% C-to-T editing efficiency for NGN-protospacer adjacent motif (PAM) sites and 20.0%-93.2% C-to-T editing efficiency for NRN-PAM sites, respectively. Therefore, these constructed base editors have emerged as powerful tools for gene function research, metabolic engineering, genetic improvement, and functional genomics research in K. phaffii.

Detection and Genomic Characterization of Torque Teno Virus in Pneumoconiosis Patients in China.

Pneumoconiosis is a common occupational disease that can worsen with accompanying infection. Torque teno virus (TTV) is a prevalent human virus with multiple genotypes that can chronically and persistently infect individuals. However, the prevalence of TTV in pneumoconiosis patients is still unclear. This research aims to detect the presence and prevalence of TTV in the alveolar lavage fluid of pneumoconiosis patients in the Hunan Province of China using PCR. As a result, a 65.5% positive rate (19 out of 29) of TTV was detected. The TTV detection rate varies among different stages of silicosis and different pneumoconiosis patient ages. Nine novel TTV genomes ranging in size from 3719 to 3908 nt, named TTV HNPP1, HNPP2, HNPP3, HNPP4, HNPP5, HNPP6-1, HNPP6-2, HNPP7-1 and HNPP7-2, were identified. A genomic comparison and phylogenetic analysis indicated that these nine TTVs represent five different species with high genetic diversity which belong to the genus Alphatorquevirus. HNPP6-1 and HNPP6-2 belong to TTV3, HNPP5 belongs to TTV13, HNPP1 belongs to TTV24, HNPP4 belongs to TTV20, and the others belong to TTV19. The genomes of TTV HNPP1, HNPP6-1, and HNPP6-2 contain three putative open reading frames (ORFs) coding for proteins, ORF1, ORF2, and ORF3, while the other six TTV genomes contain two ORFs coding for proteins, ORF1 and ORF2. These results provide the first description of TTV epidemiology in pneumoconiosis patients in China. The newly identified TTV genome sequences reveal the high genetic diversity of TTV in pneumoconiosis patients and could contribute to a deeper understanding of TTV retention and infection in humans.

Nanophthalmos-Associated MYRF gene mutation facilitates intraocular inflammation in mice.

PURPOSE: Patients with nanophthalmos might be prone to developing intraocular inflammation following an acute glaucoma attack. Here, we aimed to investigate the role of MYRF in intraocular inflammation by modeling the mutation in mice. METHODS: Nanophthalmos frameshift mutation of Myrf was introduced into the mouse genome with the CRISPR-Cas9 system. Signaling pathways in eye tissues were delineated using RNA sequencing and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Intraocular inflammation was induced by a lipopolysaccharide (LPS) intravitreal injection. Dexamethasone (DEX) was administered systemically and locally a week before the LPS injection. The anterior segment clinical scores of the mice were examined 24 h after the LPS injection. Infiltrating inflammatory cells were evaluated with histopathology and immunofluorescence. The mRNA levels of inflammatory cytokines were quantified with reverse transcription-quantitative PCR (RT-qPCR) and the corresponding protein concentrations using enzyme-linked immunosorbent assay (ELISA). RESULTS: Many inflammation-associated signaling pathways were enriched in Myrf mut/+ mice ocular tissues. Clinical scores of Myrf mut/+ mice were significantly higher than those of Myrf +/+ mice 24 h after LPS administration. Histological examination demonstrated high inflammatory cell infiltration in the anterior and vitreous chambers in Myrf mut/+ mice, with numerous CD45+ and CD11b+ inflammatory cells. Moreover, enhanced expression of inflammatory cytokines MCP-1, TGF-ß, and IL-1ß in eyes and aqueous humor of Myrf mut/+ mice was detected. Remarkably, pretreating Myrf mut/+ mice with DEX relieved the intraocular inflammation. CONCLUSION: Nanophthalmos-associated MYRF mutation renders mouse eyes more susceptible to inflammation. Dexamethasone treatment ameliorates the inflammatory response.

Maillard reaction intermediates in Chinese Baijiu and their effects on Maillard reaction related flavor compounds during aging.

This study investigated the Maillard reaction in Baijiu and the effects of extended aging in the presence of Maillard reaction intermediates (MRIs) on aromatic compounds, particularly focusing on heterocyclic changes. MRIs with different aroma types in Baijiu aged 1-18 years and force-aged for 6 weeks were determined. Results revealed that MRIs in soy sauce aroma-type Baijiu were significantly more abundant than those in other types of Baijiu. Changes in MRIs were observed and compared in aging and forced-aging Baijiu. Additionally, the distribution and variation of heterocycles in Baijiu were examined, which revealed an increase in N-heterocycle levels but a decrease in S- and O-heterocycle levels to a certain extent. The results of this study demonstrate that the Maillard reaction during the aging of Baijiu influences heterocycle concentrations, thereby improving flavor of aged Baijiu. Research into heterocycles and the Maillard reaction may help elucidate the aromatic evolution of Baijiu with aging and provide guidance for Baijiu storage.

Zonular instability-associated morphologic features in eyes with primary angle closure disease using the swept-source anterior segment - optical coherence tomography system.

BACKGROUND: This study aims to investigate the morphologic features of the crystalline lens in Primary Angle Closure Disease (PACD) patients with zonular instability during cataract surgery using the swept-source CASIA 2 Anterior Segment-Optical Coherence Tomography (AS-OCT) system. METHODS: A total of 398 eyes (125 PACD eyes with zonular instability, 133 PACD eyes with zonular stability, and 140 cataract patient controls) of 398 patients who underwent cataract surgery combined or not glaucoma surgery between January 2021 and January 2023 were enrolled. The crystalline lens parameters were measured by CASIA2 AS-OCT. Then, logistic regression was performed to evaluate the risk factors associated with zonular instability. RESULTS: The results revealed that PACD eyes had a more anterior lens equator position, a steeper anterior curvature of lens, shorter Axial Length (AL), shallower Anterior Chamber Distance (ACD), higher Lens Vault (LV) and thicker Lens Thickness (LT), when compared to eyes in the cataract control group. Furthermore, PACD eyes in the zonular instability group had steeper front R, front Rs and Front Rf, flatter back Rf, thicker lens anterior part thickness, higher lens anterior-to-posterior part thickness ratios, shallower ACD, and greater LV, when compared to PACD eyes with zonular stability. The logistic regression analysis, which was adjusted for age and gender, revealed that zonular instability was positively correlated with anterior part thickness, lens anterior-to-posterior part thickness ratio, and LV, but was negatively correlated with lens anterior radius and ACD. CONCLUSION: Steeper anterior curvature, increased lens anterior part thickness, higher anterior-to-posterior part thickness ratio, shallower ACD, and greater LV are the anatomic features of PACD eyes associated with zonular instability.

Novel diagnostic indicators for acute angle closure secondary to lens subluxation based on anterior segment and lens parameters.

Purpose: To explore stable and sensitive indicators for clinical diagnosis of acute angle closure (AAC) secondary to lens subluxation (LS) through quantitative analysis of CASIA 2 imaging.Design: A prospective cross-sectional study. Methods: Setting: Clinical practice.Participants: 23 patients with unilateral acute angle closure secondary to lens subluxation and 23 cataract patients without lens subluxation were recruited. Lens subluxation was confirmed by ultrasound biomicroscope diagnosis. The contralateral eyes without LS served as fellow control group. The cataract eyes without LS were enrolled in blank control group.Intervention: Participants underwent ophthalmologic examinations including slit-lamp biomicroscope, best corrected visual acuity, intraocular pressure, central corneal thickness measurement, axial length, gonioscopy, ultrasound biomicroscope and 360-degree anterior chamber and crystalline lens scan protocols of CASIA 2 system.Main outcome measures: Automated circumferential anterior segment and lens morphological parameters under anterior segment optical coherence tomography were analyzed via three-dimensional analysis. Results: Significant differences were found in the front and back radius of the lens, the front and back radius of steep curvature of the lens, lens thickness, lens decentration, lens diameter, iris-trabecular contact (ITC) index, ITC area, anterior chamber depth (ACD), lens vault (LV), and iris volume between LS and controls. Among these parameters, LV, the anterior radius of steep curvature of the lens and ACD demonstrated the highest prediction power (AUC = 0.87, 0.89, and 0.86, respectively). The prediction power of tilt/axis was much higher in the Gaussian Naive Bayes model (AUCs = 0.90) than in the logistic model (AUCs = 0.74). Combination of LV_mean, LV_std, tilt and tilt axis in Gaussian Naive Bayes model presented as most stable and excellent diagnostic markers for AAC secondary to LS (AUCs = 0.98). Conclusions: The combination of markers including lens tilt and lens vault in the mathematic model facilitate clinical work as it not only provides novel diagnostic indications and possible prompt treatment for AAC secondary to lens subluxations, but also enhances our understanding of the pathogenic role of zonulopathy in angle closure glaucoma.

An Assessment of Human Opportunistic Pathogenic Bacteria on Daily Necessities in Nanjing City during Plum Rain Season.

The plum rain season is a special climatic phenomenon in east Asia, which is characterized by persistent rainfall, a high temperature, and humidity, providing suitable environmental conditions for certain pathogenic bacteria, thus increasing the incidence of respiratory, gastrointestinal, and urinary diseases. However, studies on human opportunistic pathogenic bacteria communities during the plum rain season are still limited. In this study, the characteristics of human opportunistic pathogenic bacterial communities on daily necessities during the non-plum and plum rain seasons were investigated using high-throughput sequencing technology. The results revealed that the relative abundance of human opportunistic pathogenic bacteria was higher in the plum rain season (cotton cloth: 2.469%, electric bicycles: 0.724%, rice: 3.737%, and washbasins: 5.005%) than in the non-plum rain season (cotton cloth: 1.425%, electric bicycles: 0.601%, rice: 2.426%, and washbasins: 4.801%). Both temperature and relative humidity affected human opportunistic pathogenic bacterial communities. Stochastic processes dominated the assembly process of human opportunistic pathogenic bacterial communities, and undominated processes prevailed. The stability of the co-occurrence network was higher in the non-plum rain season than that in the plum rain season. In addition, the proportion of deterministic processes showed the same trend as the complexity of the co-occurrence network.

Scd-1 deficiency promotes the differentiation of CD8+ T effector.

The impact of various fatty acid types on adaptive immunity remains uncertain, and their roles remain unelucidated. Stearoyl-CoA desaturase (Scd) is a Δ-9 desaturase, which is a key rate-limiting enzyme for the conversion of saturated fatty acids (SFA) to monounsaturated fatty acids (MUFA) in the fatty acid de novo synthesis. Scd-1 converts stearic acid (SA) and palmitic acid (PA) to oleic acid (OA) and palmitoleic acid (PO), respectively. In this study, through a series of experiments, we showed that Scd-1 and its resulting compound, OA, have a substantial impact on the transformation of CD8+ naïve T cells into effector T cells. Inactivation of Scd-1 triggers the specialization of CD8+ T cells into the Teff subset, enhancing the effector function and mitochondrial metabolism of Teff cells, and OA can partially counteract this. A deeper understanding of lipid metabolism in immune cells and its impact on cell function can lead to new therapeutic approaches for controlling the immune response and improving prognosis.

Technical note: Generalizable and promptable artificial intelligence model to augment clinical delineation in radiation oncology.

BACKGROUND: Efficient and accurate delineation of organs at risk (OARs) is a critical procedure for treatment planning and dose evaluation. Deep learning-based auto-segmentation of OARs has shown promising results and is increasingly being used in radiation therapy. However, existing deep learning-based auto-segmentation approaches face two challenges in clinical practice: generalizability and human-AI interaction. A generalizable and promptable auto-segmentation model, which segments OARs of multiple disease sites simultaneously and supports on-the-fly human-AI interaction, can significantly enhance the efficiency of radiation therapy treatment planning. PURPOSE: Meta's segment anything model (SAM) was proposed as a generalizable and promptable model for next-generation natural image segmentation. We further evaluated the performance of SAM in radiotherapy segmentation. METHODS: Computed tomography (CT) images of clinical cases from four disease sites at our institute were collected: prostate, lung, gastrointestinal, and head & neck. For each case, we selected the OARs important in radiotherapy treatment planning. We then compared both the Dice coefficients and Jaccard indices derived from three distinct methods: manual delineation (ground truth), automatic segmentation using SAM's 'segment anything' mode, and automatic segmentation using SAM's 'box prompt' mode that implements manual interaction via live prompts during segmentation. RESULTS: Our results indicate that SAM's segment anything mode can achieve clinically acceptable segmentation results in most OARs with Dice scores higher than 0.7. SAM's box prompt mode further improves Dice scores by 0.1∼0.5. Similar results were observed for Jaccard indices. The results show that SAM performs better for prostate and lung, but worse for gastrointestinal and head & neck. When considering the size of organs and the distinctiveness of their boundaries, SAM shows better performance for large organs with distinct boundaries, such as lung and liver, and worse for smaller organs with less distinct boundaries, like parotid and cochlea. CONCLUSIONS: Our results demonstrate SAM's robust generalizability with consistent accuracy in automatic segmentation for radiotherapy. Furthermore, the advanced box-prompt method enables the users to augment auto-segmentation interactively and dynamically, leading to patient-specific auto-segmentation in radiation therapy. SAM's generalizability across different disease sites and different modalities makes it feasible to develop a generic auto-segmentation model in radiotherapy.

Sex, health status and habitat alter the community composition and assembly processes of symbiotic bacteria in captive frogs.

BACKGROUND: Frogs are critical economic animals essential to agricultural ecosystem equilibrium. However, Meningitis-like Infectious Disease (MID) often affects them in agricultural settings. While frog-associated microbiota contribute to elemental cycling and immunity, the effects of frog sex and health on gut bacteria remain understudied, and the relationship between frog habitat and soil microbes is unclear. We aimed to determine how frog sex, health status and habitat influence symbiotic bacteria and community assembly mechanism to provide guidance for sustainable frog farming and conservation. RESULTS: We employed 16S rRNA sequencing to investigate gut microbiota differences in relation to frog sex and health status. We also compared symbiotic communities in frog-aggregation, native and soybean soil on the farm. Results showed that gut bacterial ß-diversity and taxonomy were markedly influenced by frog sex and health. Healthy frogs had more robust gut bacterial metabolism than frogs infected with MID. Cooccurrence network analysis revealed that healthy female frogs had more complex microbial network structure than males; however, diseased males showed the greatest network complexity. The assembly mechanism of gut bacteria in male frogs was dominated by deterministic processes, whereas in female frogs it was dominated by stochastic processes. Among symbiotic bacteria in frog habitat soils, deterministic processes predominantly shaped the community assembly of soybean soil. In particular, soybean soil was enriched in pathogens and nitrogen functions, whereas frog-aggregation soil was markedly increased in sulphur respiration and hydrocarbon degradation. CONCLUSION: Our study reveals that sex mainly alters the interaction network and assembly mechanism of frog intestinal bacteria; MID infection significantly inhibits the metabolic functions of intestinal bacteria. Furthermore, diverse frog habitat soils could shape more symbiotic bacteria to benefit frog farming. Our findings provide new horizons for symbiotic bacteria among frogs, which could contribute to sustainable agriculture and ecological balance.

The insights into the phage communities of fermented foods in the age of viral metagenomics.

Phages play a critical role in the assembly and regulation of fermented food microbiome through lysis and lysogenic lifestyle, which in turn affects the yield and quality of fermented foods. Therefore, it is important to investigate and characterize the diversity and function of phages under complex microbial communities and nutrient substrate conditions to provide novel insights into the regulation of traditional spontaneous fermentation. Viral metagenomics has gradually garnered increasing attention in fermented food research to elucidate phage functions and characterize the interactions between phages and the microbial community. Advances in this technology have uncovered a wide range of phages associated with the production of traditional fermented foods and beverages. This paper reviews the common methods of viral metagenomics applied in fermented food research, and summarizes the ecological functions of phages in traditional fermented foods. In the future, combining viral metagenomics with culturable methods and metagenomics will broaden the scope of research on fermented food systems, revealing the complex role of phages and intricate phage-bacterium interactions.

Aptamer-functionalized gold nanoparticles for mercury ion detection in a colorimetric assay based on color change time as signal readout.

A universal strategy for a rapid colorimetric method for Hg2+ in an aqueous solution is described. The specific binding of Hg2+ (thymine-Hg2+-thymine) with thiolated DNA-functionalized gold nanoparticles (AuNPs) via Au-S bonds increases the spatial hindrance of the AuNP surface, resulting in a weakened catalytic ability of AuNPs to catalyze the reaction between p-nitrophenol and NaBH4. Therefore, the color change time (CCT) of the solution from yellow to colorless becomes longer. Based on the kinetic curve of absorbance over time measured by a UV spectrometer, the level of Hg2+ in aqueous solutions can be easily quantified. A linear relationship between CCT and Hg2+ concentration was obtained in the 10-600-nM range with a detection limit of 0.20 nM, which is much lower than the limit value (10 nM) defined by the US Environmental Protection Agency for Hg2+ in drinking water. The excellent sensitivity comes from CCT as the signal output of the probe, rather than the absorbance or wavelength change used in traditional colorimetric probes as the signal output.

Finite element analyses of three minimally invasive fixation techniques for treating Sanders type II intra-articular calcaneal fractures.

BACKGROUND AND OBJECTIVE: Calcaneal Sanders type II or III fractures are highly disabling with significant burden. Surgical treatment modalities include open reduction and internal fixation (ORIF) techniques and a variety of minimally invasive surgical (MIS) approaches. ORIF techniques are associated with complications and traditional MIS techniques need extensive intraoperative fluoroscopic procedures. The present study aims to investigate the effects of three different minimally invasive internal fixation (MIIF) techniques used to treat Sanders type II intra-articular calcaneal fractures using finite element analyses. METHODS: A 64-row spiral computed tomography scan was used to observe the calcaneus of a healthy adult. The scanning data were imported into Mimics in a DICOM format. Using a new model of a Sanders type II-B intra-articular calcaneal fracture, three minimally invasive techniques were simulated. Technique A involved fixation using an isolated minimally invasive locking plate; Technique B used a minimally invasive locking plate with one medial support screw; and Technique C simulated a screw fixation technique using four 4.0-mm screws. After simulating a 640-N load on the subtalar facet, the maximum displacement and von Mises stress of fragments and implants were recorded to evaluate the biomechanical stability of different fixation techniques using finite element analyses. RESULTS: After stress loading, the maximum displacements of the fragments and implants were located at the sustentaculum tali and the tip of sustentaculum tali screw, respectively, in the three techniques; however, among the three techniques, Technique B had better results for displacement of both. The maximum von Mises stress on the fragments was < 56 Mpa, and stress on the implants using the three techniques was less than the yield strength, with Technique C having the least stress. CONCLUSION: All three techniques were successful in providing a stable fixation for Sanders type II intra-articular calcaneal fractures, while the minimally invasive calcaneal locking plate with medial support screw fixation approach exhibited greater stability, leading to improved enhancement for the facet fragment; however, screw fixation dispersed the stress more effectively than the other two techniques.

Correction: Orexin-A Promotes Cell Migration in Cultured Rat Astrocytes via Ca2+-Dependent PKCα and ERK1/2 Signals.

[This corrects the article DOI: 10.1371/journal.pone.0095259.].

Rational Redesign of Chitosanase to Enhance Thermostability and Catalytic Activity to Produce Chitooligosaccharides with a Relatively High Degree of Polymerization.

Chitooligosaccharides (hdpCOS) with a high degree of polymerization (hdp, DP 4-10) generally have greater biological activities than those of low-DP (ldp, DP 2-3) COS. Chitosanase from Bacillus amyloliquefaciens KCP2 (Csn46) can degrade chitosan to more hdpCOS at high temperature (70 °C), but low thermal stability at this temperature makes it unsuitable for industrial application; the wild-type enzyme can only produce COS (DP 2-4) at lower temperatures. Several thermostable mutants were obtained by modifying chitosanase using a comprehensive strategy based on a computer-aided mutant design. A combination of four beneficial single-point mutations (A129L/T175 V/K70T/D34G) to Csn46 was selected to obtain a markedly improved mutant, Mut4, with a half-life at 60 °C extended from 34.31 to 690.80 min, and the specific activity increased from 1671.73 to 3528.77 U/mg. Mut4 produced COS with DPs of 2-4 and 2-7 at 60 and 70 °C, respectively. Therefore, Mut4 has the potential to be applied to the industrial-scale preparation of hdpCOS with high biological activity.

Patterns of bacterial distance decay and community assembly in different land-use types as influenced by tillage management and soil layers.

Land use and cover change are major factors driving global change and greatly impact terrestrial organisms, especially soil microbial diversity. Little is known, however, about bacterial diversity, distribution patterns and assembly processes across different land use types. In this study, therefore, we conducted a large-scale field survey of 48 sampling sites, encompassing different land use types in Xuancheng city, China, with different degrees of soil disturbance and different soil horizons. The distance-decay relationships (DDRs), assembly processes and the spatial patterns of soil bacterial communities were investigated based on high-throughput sequencing data. We found that the DDRs might be weakened by anthropogenic disturbances, which were not observed in tilled soils, while a decreasing trend was observed along the soil horizon in untilled soils. The relative importance of environmental factors and geographic distance varied with soil tillage. Specifically, bacterial communities in tilled soils were driven by non-spatially autocorrelated environmental factors, while untilled soils were more susceptible to geographic distance. In addition, the heterogeneity of soil properties, as well as the differences in soil bacterial niche width and niche overlap, determined the assembly processes of the bacterial community, resulting in opposite trends along the soil layers in tilled and untilled soils. These findings expand the current understanding of the biogeography of soil bacterial communities across different land use types.

Selection of initial microbial community for the alcoholic fermentation of sesame flavor-type baijiu.

The initial microbial community is critical for the production of volatile metabolites during traditional food fermentations. Selection of the initial community plays an important role in improving the quality of fermented foods. Here, we used high-throughput amplicon sequencing combined with multivariate statistical methods to explore the microbial succession in stacking and alcoholic fermentation stages in sesame flavor-type baijiu making. We proposed a selection strategy for the initial microbial community in the alcoholic fermentation stage, which determined the quality of baijiu. Results suggested that the microbial composition statistically differed between stacking and alcoholic fermentation stages (ANOSIM, Bacteria: R = 0.60, P = 0.001; Fungi: R = 0.53, P = 0.001). Microbial succession drove metabolic succession (Bacteria: r = 0.87, P < 0.05; Fungi: r = 0.56, P < 0.05) in alcoholic fermentation. The fermentation time of stacking fermentation determined the initial community for alcoholic fermentation, and it can be used as a criterion for selection of the initial microbial community for alcoholic fermentation. The succession distance of the microbial community was varied and reached the highest (Bacteria: 0.048, Fungi: 0.064) at 30 h in stacking fermentation. When we selected 30 h as stacking fermentation time, the concentration (4.58 mg/kg) and diversity (0.61) of volatile metabolites were highest at the end of alcoholic fermentation. This work developed a succession distance-guided approach to select the initial microbial community for the alcoholic fermentation of sesame flavor-type baijiu. This approach can be used to improve the quality of baijiu.