Complex Microflora Research Articles

Application of novel dual-ligand co metal-organic framework/graphene oxide for electrocatalytic oxidative degradation of bisphenol A in marine wastewater

The adjustment of the electron distribution of 2D metal-organic frameworks (2D-MOFs), as a hot anode candidate for electrocatalytic oxidation, is crucial for its application. In this work, a new electron distribution was achieved with dual-ligand connection and graphene oxide (GO) loading and the complex of dual-ligand 2D-MOF/GO (Co-IH/GO) exhibit faster electron transfer efficiency (Rct = 62.5) and more active sites (ID/IG = 1.01). Co-IH/GO demonstrated excellent electrocatalytic performance and achieved 100 % electrocatalytic degradation of bisphenol A (BPA) within 10 min. In addition, superior properties of stability, temperature tolerance, and pH tolerance were achieved, after 5 cycles of degradation, the catalyst was able to maintain 100 % degradation efficiency, Capable of maintaining good degradation performance over a temperature range of 25 °C–45 °C and a wide pH range of pH = 5–11. Both experimental and electron paramagnetic resonance analysis results indicated that 1O2 acted as the dominant active substrate. With the involvement of Cl− in marine wastewater, activated chlorine was also generated during the reaction, which contributed to fast BPA degradation. Furthermore, the established dual-ligand 2D-MOF/GO electrocatalytic system exhibited superior activity for the degradation of dyes and complex microflora, while the solar-driven degradation experiment shed light on the independence of fossil and stationary sources of energy.

Microbiological, Functional, and Chemico-Physical Characterization of Artisanal Kombucha: An Interesting Reservoir of Microbial Diversity.

Kombucha is a trending tea fermented via a complex microflora of yeasts and acetic acid bacteria. It can be a valid low-calorie substitute for soft drinks due to its sour, naturally carbonated, and sweet taste. Despite increased interest, the microflora and functional properties of kombucha have not yet been fully understood. The aim of this work was to characterize, from a microbiological, chemico-physical, and functional point of view, three types of artisanal kombucha obtained by fermenting green tea containing sugar by means of different starter cultures. Metagenomic analysis revealed a predominance of yeasts compared to bacteria, regardless of the sample. In particular, Brettanomyces spp. was found to be the dominant yeast. Moreover, the different types of kombucha had different microbial patterns in terms of acetic acid bacteria and yeasts. Ethanol and acetic acid were the dominant volatile molecules of the kombucha volatilome; the samples differed from each other in terms of their content of alcohols, esters, and acids. All the samples showed a high antioxidant potential linked to the high content of phenols. This study confirmed the positive chemico-physical and functional properties of kombucha and indicated that the microflora responsible for the fermentation process can significantly affect the characteristics of the final product.

Plant Growth Promoting Rhizobacteria for Sustainable Production of Sugarcane and Rice

Sugarcane (Sacchraum officinarum L.) and rice (Oryza sativa L.) are important cash and staple crop in the world respectively. In today’s population explosion the lots of pressure on cropping land to mitigate the feed need of consumers with judicious use of chemical fertilizers without considering the health of soil and its sustainability. The rhizobacteria live region around roots (2-80 mm) of crop with divers, dynamic and complex microflora having capacity with direct and indirect beneficial effects on crop health by availability of different nutrient, siderophores, rhizo deposits, auxins and role with bioremediation. There are different types of bacteria is isolated from rhizosphere of sugarcane and rice having Bacillus, Rhizobium, comamonas, cyanaobacteria, Nodosilinea, Levinella and Pseudomonas genera with most efficient nitrogen producer, solubilizers of inorganic phosphate, potash and other macro and micronutrient. In rice microbiome as Levinella, Psudomonas Anaeromyxobacter, Arenimonas, Arthrobacter, Bacillus, Bellilinea Proteobacteria, Chloroflexi, Actinobacteria, Acidobacteria and cyanobacteria with strains of Nitrosomonas and Nitrobacter are further divided in vegetative and reproductive growth stage of rice crop. The article give brief idea about the large arena of them.

Woman’s microbiome and obstetrical and perinatal risks: what do they have in common?

The article is devoted to the review of modern scientific publications about the microbiome of a woman and its importance in obstetric and perinatal practice. The composition of the microbiome is changed both in the process of human evolution and personally and in different periods of a person’s life. However, on the other hand, the microbiome is influenced by the specific environment in which a person lives. It consists of a certain collection of genomes of all microorganisms. Complications during pregnancy occur frequently, according to statistics – in every sixth pregnant woman, and pose a danger to the health of the mother and child.During pregnancy, the richness and diversity of the vaginal microbiome decreases, and different species of Lactobacillus play a dominant role. The microbiome stability is hypothesized to be associated with higher levels of estrogen concentration, absence of menstruation, and modification of cervical and vaginal fluids. During an uncomplicated pregnancy, the taxonomic composition of the vaginal microbiota remains stable with the exception of the period before labor, when there is an increase in microbial diversity. This makes the vaginal microbiome similar to that of a non-pregnant woman and is believed to be a trigger for the labor process to begin.The recent studies have determined a relationship between changes in the microbiome during pregnancy and the occurrence of complications in these women. Any change or disturbance in the microbiome balance can be involved in inflammatory processes, which can potentially have adverse effects on the course of pregnancy. A major interaction between the oral microbiome and preeclampsia involves the production of nitrogen derivatives, especially nitric oxide (NO). NO is produced from L-arginine via NO synthases (NOS), and is involved in vascular processes, especially vasodilation and tissue protection. Also, NO is indirectly involved in the processes that occur in the presence of chronic cardiovascular diseases, including hypertension and preeclampsia.In recent years, scientists have begun actively to study a correlation between changes in the gut microbiome and various nosologies regarding gestational diabetes. There is not much of this data at the moment. The gut microbiome is known to modulate insulin resistance and the inflammatory response, and changes in the microbiome may be associated with metabolic diseases. It is hypothesized that changes in the gut microbiome may lead to metabolic diseases through several mechanisms: abnormal intestinal permeability, increased absorption of lipopolysaccharide, abnormal production of short-chain fatty acids, altered conversion of primary bile acids, and enhanced production of bacterial toxins (e.g., trimethylamine-N-oxide).During full-term pregnancy, the “dynamic stability” of the vaginal microbiome is described as a higher concentration of Lactobacillus species starting at 20 weeks of gestation due to increased glycogen availability and a less complex and diverse microflora. This condition may be due to the lack of cyclical hormonal changes during pregnancy. Lactobacillus and small bacterial diversity are thought to be critical factors for the initiation of labor at the end of the pregnancy.Future therapeutic strategies are likely to be applied to modulate the composition of the microbiome, including the use of pro- and prebiotics and dietary modification. However, further research is needed to identify specific tools that can be used to develop personalized therapeutic approaches for individualized prevention and treatment.

16S rRNAメタゲノム解析を利用した<i>Staphylococcus aureus</i>のバイオフィルム形成に菌種間相互作用を示す菌種の特定

Staphylococcus aureus biofilm is a major contamination concern in the food processing environment. S. aureus constructs complex biofilms with environmental species, but its inter-species interactions are not well. In this study, 16S rRNA metagenomic analysis was used to identify interactors for S. aureus biofilm formation. Fifty-six microbiota samples extracted from retail foods were employed to construct biofilms with S. aureus ATCC12600 on stainless steel. Then, the composition of the microbiota was analyzed by 16S rRNA metagenomic analysis and compared with the number of S. aureus cells in the biofilm. As a result, 22 genera, especially Serratia sp. and Enterobacter sp., were suggested to be remarkably effective inhibitors of S. aureus biofilm formation. Furthermore, Serratia sp. 19-SA-0058-001 was isolated, and its inhibitory effect was confirmed. The present study demonstrated efficient strategy to identify an interactor from complex microflora.

Diel modifications in the oral and anal microflora of the Pygoscelis papua Penguins

ABSTRACT The mouths and anuses of Penguins house complex microflora, which play important roles in growth and development. In this study, 6,391,065 sequences were detected from the oral and anal microflora of gentoo (Pygoscelis papua) penguins, with Firmicutes and Proteobacteria dominating the oral and anus samples from female gentoo penguins, respectively, while in males, Proteobacteria dominated the oral samples and Firmicutes dominated the anus samples. In addition, we provide the first demonstration that the dominant oral and anal microflora of P. papua (notably Firmicutes, Proteobacteria, Actinobacteria, and Bacteriodetes) exhibit a diel rhythm. Given that the status of penguin populations remains an issue of environmental and conservation concern, our work provides important insight into the health of this penguin species by focusing on the diversity, diel rhythms, and dynamics of dominant intestinal microflora, further offering useful reference materials for future studies on the diel interactions between microflora and the penguin host.

Gut-on-a-Chip for the Analysis of Bacteria–Bacteria Interactions in Gut Microbial Community: What Would Be Needed for Bacterial Co-Culture Study to Explore the Diet–Microbiota Relationship?

Bacterial co-culture studies using synthetic gut microbiomes have reported novel research designs to understand the underlying role of bacterial interaction in the metabolism of dietary resources and community assembly of complex microflora. Since lab-on-a-chip mimicking the gut (hereafter "gut-on-a-chip") is one of the most advanced platforms for the simulative research regarding the correlation between host health and microbiota, the co-culture of the synthetic bacterial community in gut-on-a-chip is expected to reveal the diet-microbiota relationship. This critical review analyzed recent research on bacterial co-culture with perspectives on the ecological niche of commensals, probiotics, and pathogens to categorize the experimental approaches for diet-mediated management of gut health as the compositional and/or metabolic modulation of the microbiota and the control of pathogens. Meanwhile, the aim of previous research on bacterial culture in gut-on-a-chip has been mainly limited to the maintenance of the viability of host cells. Thus, the integration of study designs established for the co-culture of synthetic gut consortia with various nutritional resources into gut-on-a-chip is expected to reveal bacterial interspecies interactions related to specific dietary patterns. This critical review suggests novel research topics for co-culturing bacterial communities in gut-on-a-chip to realize an ideal experimental platform mimicking a complex intestinal environment.

Inflammatory Response: A Crucial Way for Gut Microbes to Regulate Cardiovascular Diseases.

Gut microbiota is the largest and most complex microflora in the human body, which plays a crucial role in human health and disease. Over the past 20 years, the bidirectional communication between gut microbiota and extra-intestinal organs has been extensively studied. A better comprehension of the alternative mechanisms for physiological and pathophysiological processes could pave the way for health. Cardiovascular disease (CVD) is one of the most common diseases that seriously threatens human health. Although previous studies have shown that cardiovascular diseases, such as heart failure, hypertension, and coronary atherosclerosis, are closely related to gut microbiota, limited understanding of the complex pathogenesis leads to poor effectiveness of clinical treatment. Dysregulation of inflammation always accounts for the damaged gastrointestinal function and deranged interaction with the cardiovascular system. This review focuses on the characteristics of gut microbiota in CVD and the significance of inflammation regulation during the whole process. In addition, strategies to prevent and treat CVD through proper regulation of gut microbiota and its metabolites are also discussed.

Metagenomic insights into bacterial communities and functional genes associated with texture characteristics of Kazakh artisanal fermented milk Ayran in Xinjiang, China

The complex microflora of traditional fermented milk is crucial to milk coagulation mainly through acid and protease production; however, it is still unclear which microbes and proteases significantly influence the texture of Ayran, a Kazakh artisanal fermented milk in Xinjiang, China. In this study, fifty-nine samples of Ayran were collected and investigated on texture properties. Finally, six Ayran samples with different texture features were screened out, and the taxonomic and functional attributes of their microbiota were characterized by metagenomics. The results showed that the hardness of the fermented milk in Yili Kazakh Autonomous Prefecture was significantly higher than that in other pasture areas. Lactobacillus and Lactococcus were the core genera that affected the coagulation quality of milk. Furthermore, we found that the proline iminopeptidase pip (EC 3.4.11.5) gene of Lactobacillus helveticus and Limosilactobacillus fermentum and the dipeptidase E pepE (EC 3.4.13.21) gene of Lactococcus lactis were most associated with the coagulation quality of fermented milk. Furthermore, positive correlations were observed among the hardness of fermented milk, the activity of the proteases, and the corresponding functional gene expressions.

Characterization of the core microflora and nutrient composition in packaged pasteurized milk products during storage

Pasteurized milk contains complex microbial communities affected by sterilization and storage conditions. This complex microflora may be the possible reason that pasteurized dairy products are highly prone to spoilage. In this study, packaged pasteurized milk products collected from dairy processing factories in China were stored at 0, 4, 10, 15, and 25 ºC for 0−15 days and subjected to microbial identification using high-throughput sequencing. Accordingly, 6 phyla and 44 genera were identified as the dominant microbiota. Moreover, the changes in nutritional composition of the pasteurized milk, including in 16 free amino acids, 7 taste values, and 8 chemical constituents, were analyzed using principal component and multi-factor analyses. The Pearson correlation analysis identified Pseudomonas, Aeromonas, Paenibacillus, and Serratia genera as the core functional microbiota that significantly affects the nutritional composition of pasteurized milk. Hence, the results provide a comprehensive understanding of the safety and shelf-life of stored pasteurized milk.

A novel approach for accelerating smear development on bacterial smear-ripened cheeses reduces ripening time and inhibits the growth of Listeria and other unwanted microorganisms on the rind

Bacterial smear-ripened cheeses are commonly contaminated with fungi and the potentially dangerous pathogen Listeria monocytogenes, which compromises food safety and quality. Here, we present new approach for accelerating smear development on these cheeses, while reducing growth of unwanted microorganisms. We grew the smear microorganism Brevibacterium linens in acid whey (AW) supplemented with a by-product of whey protein hydrolysate production (FCH). B. linens grew to a high cell density (10.27 log 10 CFU/mL), and alkalized the AW-FCH medium. We found that the fermented AW-FCH, with its high pH, rapidly killed L. monocytogenes and yeasts. When culture medium was smeared on the cheese surface, the surface pH was rapidly neutralized, and in just 7 days, the cheeses developed a dense orange color and growth of spoilage fungi was inhibited. Summing up, by growing B. linens to high cell density on low-value dairy byproducts, and applying dense suspensions onto cheeses, we can reduce the time needed for establishing the smear. Added benefits are increased food safety and less spoilage, as quick smear development inhibits growth of unwanted microorganisms on the rind. Preliminary tests at a dairy show that flavor development is comparable to traditional bacterial surface-ripened cheeses with far more complex surface microflora.

Exploring AI-2-mediated interspecies communications within rumen microbial communities

BackgroundThe rumen is an ecosystem with a complex microbial microflora in which microbes initiate biofilm formation by attaching to plant surfaces for plant degradation and are capable of converting feed to nutrients and energy via microbial processes. Quorum sensing (QS) is a cell-to-cell communication mechanism that allows microbes to synchronize the expression of multiple genes in the group to perform social behaviors such as chemotaxis and biofilm formation using self-synthesized QS signaling molecules. Whereas QS has been extensively studied in model microorganisms under pure culture conditions, QS mechanisms are poorly understood in complex bacterial communities, such as the rumen microflora, in which cell-to-cell communication may be common.ResultsHere, we analyzed 981 rumens bacterial and archaeal genomes from the Joint Genome Institute (JGI) and GenBank databases and identified 15 types of known QS signaling molecule-related genes. The analysis of the prevalence and abundance of genes involved in QS showed that 767 microbial genomes appeared to possess QS-related genes, including 680 bacterial genomes containing autoinducer-2 (AI-2) synthase- or receptor-encoding genes. Prevotella, Butyivibrio, Ruminococcus, Oribacterium, Selenomonas, and Treponema, known abundant bacterial genera in the rumen, possessed the greatest numbers of AI-2-related genes; these genes were highly expressed within the metatranscriptome dataset, suggesting that intra- and interspecies communication mediated by AI-2 among rumen microbes was universal in the rumen. The QS processes mediated by the dCache_1-containing AI-2 receptors (CahRs) with various functional modules may be essential for degrading plants, digesting food, and providing energy and nutrients to the host. Additionally, a universal natural network based on QS revealed how rumen microbes coordinate social behaviors via the AI-2-mediated QS system, most of which may potentially function via AI-2 binding to the extracellular sensor dCache_1 domain to activate corresponding receptors involved in different signal transduction pathways, such as methyl-accepting chemotaxis proteins, histidine kinases, serine phosphatases, c-di-GMP synthases and phosphodiesterases, and serine/threonine kinases in the rumen.ConclusionsThe exploration of AI-2-related genes, especially CahR-type AI-2 receptors, greatly increased our insight into AI-2 as a potentially “universal” signal mediating social behaviors and will help us better understand microbial communication networks and the function of QS in plant-microbe interactions in complex microecosystems.DGdc6xosz2q-6EKgKy6aZ-Video

Cross-reactivity of antibodies to different rumen methanogens demonstrated using immunomagnetic capture technology.

Methane is produced in the rumen of ruminant livestock by methanogens, accounting for approximately 14.5% of anthropogenic greenhouse gas emissions in terms of global warming potential. The rumen contains a diversity of methanogens species, and only a few of these have been cultured. Immunomagnetic capture technology (ICT) is a simple and effective method to capture and concentrate target organisms in samples containing complex microflora. We hypothesized that antibody-coated magnetic beads could be used to demonstrate antibody specificity and cross-reactivity to methanogens in rumen samples. Sheep polyclonal antibodies raised against four isolates of rumen dwelling methanogens, Methanobrevibacter ruminantium strain M1, Methanobrevibacter sp. AbM4, Methanobrevibacter sp. D5, and Methanobrevibacter sp. SM9 or an equal mix of all four isolates, were used to coat paramagnetic beads. ICT was used together with flow cytometry and qPCR to optimize key parameters: the ratio of antibody to beads, coupling time between antibody and paramagnetic beads to produce immunomagnetic beads (IMBs), and optimal incubation time for the capture of methanogen cells by IMBs. Under optimized conditions, IMBs bound strongly to their respective isolates and showed a degree of cross-reactivity with isolates of other Methanobrevibacter spp. in buffer and in rumen fluid, and with resident methanogens in rumen content samples. The evidence provided here indicates that this method can be used to study the interaction of antibodies with antigens of rumen methanogens, to understand antigen cross-reactivity and antibody binding efficiency for the evaluation of antigens used for the development of a broad-spectrum anti-methanogen vaccine for the abatement of methane production.

Structural variability and niche differentiation of Paeonia lactiflora's root-associated microbiomes

Many microorganisms are found in the roots of plants, and are important for plant growth, nutrition uptake, and disease prevention. While the microorganisms of many crops such as soybean, rice, and maize have been studied, the root-associated microbial diversity of horticultural plants such as Paeonia lactiflora has been little studied. In this study, we investigated the composition, abundance, diversity and variability of microorganisms associated with different rhizospheric compartments (bulk soil, rhizosphere, rhizoplane, root endosphere) of different cultivars of P. lactiflora. We used the root and root-associated soil of a medicinal cultivar P. lactiflora cv ‘Hang Baishao’ (HS, 2n = 10) and an ornamental cultivar P. lactiflora cv ‘Zi Fengyu’ (ZFY, 2n = 10) as our study objectives. Based on Illumina Novaseq 6000 high-throughput sequencing, the 16S rRNA V4 amplicon of two cultivars of P. lactiflora root-associated bacterial communities and the ITS1-spanning amplicon of the fungal communities were sequenced, and the microbial communities were analyzed for relevant bioinformatics. Observed Species, Simpson, Shannon, and Chao1 indices showed that the microbial diversity of the rhizosphere was greater than that of the root, with the with the diversity decreasing from the bulk soil to the root endosphere. In addition, Cyanobacteria and Proteobacteria were the most abundant of the root-associated bacterial communities, accounting for 19.59 % and 31.23 %, respectively. On the other hand, Ascomycota (37.74 %) and Basidiomycota (11.15 %) were the most dominant fungal communities in the four root-associated compartments. Compared to ZFY, the root-associated compartments of HS were able to enrich more functional bacteria associated with bacterial inhibition, such as Kribbella, Actinophytocola and Actinoallomurus. This study explored the complex root microflora structure of P. lactiflora and provided a theoretical basis for future studies on the synthetic microbial community of soil.

Complex network analysis of slaughterhouse waste anaerobic digestion: From failure to success of long-term operation

The study explored slaughterhouse waste (SHW) as prime feedstock associated with and without supplement of an external slowly degradable lignocellulosic carbon source to overcome the synergistic co-inhibitions of ammonia and fatty acids. Long-term solid-state digestion (SSD) and liquid-state digestion (LSD) were investigated using a mixture of pork liver and fat. At 2.0 g volatile solids (VS) L−1 d−1 of organic loading rate (OLR), the two reactors of SSD experienced operational instability due to ammonia inhibition and volatile fatty acid (VFA) accumulation while LSD successfully produced 0.725 CH4 L CH4 g−1VS during 197 d of working days under unfavorable condition with high total ammonia nitrogen (>4.7 g/L) and VFAs concentration (>1.9 g/L). The network analysis between complex microflora and operational parameters provided an insight for sustainable biogas production using SHW. Among all, hydrogenotrophic methanogens have shown better resistance than acetoclastic methanogens.

Exploring the Fungal Community and Its Correlation with the Physicochemical Properties of Chinese Traditional Fermented Fish (Suanyu).

Suanyu is a traditional natural fermented fish product from Southwest China that contains very complex microflora. The main purpose of this study was to explore the fungal community and its relationship with the physicochemical properties of Suanyu. The fungal community structure of Suanyu from the main provinces (Guizhou and Hunan) was studied via high-throughput sequencing. The correlation between dominant fungi and physicochemical characteristics was analyzed via Spearman’s correlation coefficient. The results showed that the pH value, total volatile base nitrogen content, and thiobarbituric acid reactive substance content ranges of Suanyu samples were 4.30–5.50, 17.11–94.70 mg/100 g, and 0.61 to 3.62 mg/kg, respectively. The average contents of total volatile base nitrogen, thiobarbituric acid reactive substance, and total BAs in Suanyu from Guizhou were lower than those from Hunan. The main BAs were phenethylamine, putrescine, cadaverine, histamine, and tyramine. Ascomycota was the dominant fungal phylum, and Kodamaea, Debaryomyces, Wallemia, Zygosaccharomyces, and unclassified Dipodascaceae were the dominant fungal genera in different samples. Moreover, high abundance levels of Kodamaea and Zygosaccharomyces were found in Suanyu from Guizhou. According to the correlation analysis, Kodamaea and Zygosaccharomyces were negatively correlated with TBARS (R2 = −0.43, −0.51) and TVBN (R2 = −0.37, −0.29), and unclassified Dipodascaceae was significant negatively correlated with tyramine (R2 = −0.56). This study expands the understanding of the fungal community and the fermentation characteristics of the dominant fungi in Suanyu.

Overview on agricultural potentials of biogas slurry (BGS): applications, challenges, and solutions.

The residual slurry obtained from the anaerobic digestion (AD) of biogas feed substrates such as livestock dung is known as BGS. BGS is a rich source of nutrients and bioactive compounds having an important role in establishing diverse microbial communities, accelerating nutrient use efficiency, and promoting overall soil and plant health management. However, challenges such as lower C/N transformation rates, ammonia volatilization, high pH, and bulkiness limit their extensive applications.Here we review the strategies of BGS valorization through microbial and organomineral amendments. Such cohesive approaches can serve dual purposes viz. green organic inputs for sustainable agriculture practices and value addition of biomass waste. The literature survey has been conducted to identify the knowledge gaps and critically analyze the latest technological interventions to upgrade the BGS for potential applications in agriculture fields.The major points are as follows: (1) Bio/nanotechnology-inspired approaches could serve as a constructive platform for integrating BGS with other organic materials to exploit microbial diversity dynamics through multi-substrate interactions. (2) Advancements in next-generation sequencing (NGS) pave an ideal pathway to study the complex microflora and translate the potential information into bioprospecting of BGS to ameliorate existing bio-fertilizer formulations. (3) Nanoparticles (NPs) have the potential to establish a link between syntrophic bacteria and methanogens through direct interspecies electron transfer and thereby contribute towards improved efficiency of AD. (4) Developments in techniques of nutrient recovery from the BGS facilities’ negative GHGs emissions and energy-efficient models for nitrogen removal. (5) Possibilities of formulating low-cost substrates for mass-multiplication of beneficial microbes, bioprospecting of such microbes to produce bioactive compounds of anti-phytopathogenic activities, and developing BGS-inspired biofertilizer formulations integrating NPs, microbial inoculants, and deoiled seed cakes have been examined.Graphical abstract

Nondestructive multiplex detection of foodborne pathogens with background microflora and symbiosis using a paper chromogenic array and advanced neural network

We have developed an inexpensive, standardized paper chromogenic array (PCA) integrated with a machine learning approach to accurately identify single pathogens (Listeria monocytogenes, Salmonella Enteritidis, or Escherichia coli O157:H7) or multiple pathogens (either in multiple monocultures, or in a single cocktail culture), in the presence of background microflora on food. Cantaloupe, a commodity with significant volatile organic compound (VOC) emission and large diverse populations of background microflora, was used as the model food. The PCA was fabricated from a paper microarray via photolithography and paper microfluidics, into which 22 chromogenic dye spots were infused and to which three red/green/blue color-standard dots were taped. When exposed to VOCs emitted by pathogens of interest, dye spots exhibited distinguishable color changes and pattern shifts, which were automatically segmented and digitized into a ΔR/ΔG/ΔB database. We developed an advanced deep feedforward neural network with a learning rate scheduler, L2 regularization, and shortcut connections. After training on the ΔR/ΔG/ΔB database, the network demonstrated excellent performance in identifying pathogens in single monocultures, multiple monocultures, and in cocktail culture, and in distinguishing them from the background signal on cantaloupe, providing accuracy of up to 93% and 91% under ambient and refrigerated conditions, respectively. With its combination of speed, reliability, portability, and low cost, this nondestructive approach holds great potential to significantly advance culture-free pathogen detection and identification on food, and is readily extendable to other food commodities with complex microflora.

Screening of Cellulose Degrading Bacteria and Construction of Complex Microflora

The collected samples were pre-screened with Congo red cellulose medium according to the ratio of transparent circle diameter/colony diameter, and 10 strains with strong ability to decompose cellulose were obtained. Then, these strains were inoculated into the liquid production enzyme medium to measure the CMC enzyme activity for rescreening, and finally the N05, N13, N213 strain high-efficiency cellulose degradation strains were screened. These three strains were combined and cultured, and the best combination of effects was obtained by comparing the enzyme activities.

Contemporary Microbial and Antimicrobial Considerations in Regenerative Endodontic Therapy

IntroductionRegenerative endodontic therapy (RET) has gained considerable attention and wide approval. Although it is being performed routinely, the outcomes remain unpredictable, and the optimal approaches for treatment are not established. It has been shown that bacterial persistence in root canals in these cases significantly interferes with healing and root maturation. However, few objective clinical studies have evaluated the complex microflora present in the infections or the efficacy of various clinical procedures. In addition, the extent of the infection and biofilm maturation in immature teeth with necrotic pulp has been understudied. Furthermore, most models used in preclinical evaluation of these issues do not fully elucidate the complexity or variability of the clinical situation. Results and ConclusionIn this review, the main biological and clinical problems pertaining to RET will be discussed. Contemporary analysis of complex microbial communities will be reviewed with emphasis on how these types of analyses can provide clinically useful data. In addition, current and proposed approaches for the effective disinfection of the root canal environment without interference with stem cell viability or integrity of the dentin matrix in these cases will be explored. The future of research in this field, including better and more customizable approaches in RET, in light of recent technological advances and progress in endodontics, will be outlined.