Major Bacterial Genera Research Articles

Comparative analysis of bacterial communities associated with healthy and diseased corals in the Indonesian sea.

Coral reef ecosystems are impacted by climate change and human activities, such as increasing coastal development, overfishing, sewage and other pollutant discharge, and consequent eutrophication, which triggers increasing incidents of diseases and deterioration of corals worldwide. In this study, bacterial communities associated with four species of corals: Acropora aspera, Acropora formosa, Cyphastrea sp., and Isopora sp. in the healthy and disease stages with different diseases were compared using tagged 16S rRNA sequencing. In total, 59 bacterial phyla, 190 orders, and 307 genera were assigned in coral metagenomes where Proteobacteria and Firmicutes were pre-dominated followed by Bacteroidetes together with Actinobacteria, Fusobacteria, and Lentisphaerae as minor taxa. Principal Coordinates Analysis (PCoA) showed separated clustering of bacterial diversity in healthy and infected groups for individual coral species. Fusibacter was found as the major bacterial genus across all corals. The lower number of Fusibacter was found in A. aspera infected with white band disease and Isopora sp. with white plaque disease, but marked increases of Vibrio and Acrobacter, respectively, were observed. This was in contrast to A. formosa infected by a black band and Cyphastrea sp. infected by yellow blotch diseases which showed an increasing abundance of Fusibacter but a decrease in WH1-8 bacteria. Overall, infection was shown to result in disturbance in the complexity and structure of the associated bacterial microbiomes which can be relevant to the pathogenicity of the microbes associated with infected corals.

Does dysbiotic endometrium affect blastocyst implantation in IVF patients?

PurposeTo analyze the pregnancy outcomes of IVF patients presenting eubiotic or dysbiotic endometrium at the time of embryo transfer and to analyze what bacterial profiles are suitable for embryo implantation.MethodsNinety-nine IVF patients under 40 years old undergoing vitrified-warmed blastocyst transfer in HRT cycle had concurrent endometrial microbiome analysis. Samples from the endometrium were taken from the participants at the time of mock transfer; the bacterial profiles at genus level and percentage of lactobacilli in the endometrium of the patients were analyzed.ResultsThirty-one cases (31.3%) had dysbiotic endometrium. The background profiles, pregnancy rates per transfer (52.9% vs 54.8%), and miscarriage rates (11.1% vs 5.9%) were comparable between patients with eubiotic or dysbiotic endometrium. Major bacterial genera other than Lactobacillus detected in the dysbiotic endometrium were Atopobium, Gardnerella, and Streptococcus. Some patients achieved ongoing pregnancies with 0% Lactobacillus in the endometrium. The endometrial bacterial profiles of pregnant cases with dysbiotic endometrium were comparable with those of non-pregnant cases.ConclusionAnalyzing microbiota at the species-level resolution may be necessary for identifying the true pathogenic bacteria of the endometrium and avoiding over-intervention against non-Lactobacillus microbiota. Further studies are necessary for analyzing the mechanism of how the pathogenic bacteria affect embryo implantation.

Relationship between enantioselective transformation of racemic quizalofop-ethyl and soil bacterial diversity: A destructive approach.

This study investigated the resilience of bacterial diversity in soils restored after autoclaving, in terms of richness, evenness and community structure, and its feedback on the enantioselective transformation of racemic quizalofop-ethyl (rac-QE). Microbial biomass carbon (MBC) and bacterial richness (indexed by operational taxonomic units [OTUs]) in restored soil recovered to approximately 50% and 29%, respectively, of the native soil within 43days. Bacterial evenness was much lower in restored soil than in native soil. The relative proportions of dominant bacterial genera differed significantly (P<.05) between restored and native soils. Importantly, two major bacterial genera that recolonized restored soil were not detected in native soil. Highly enantioselective transformation of rac-QE was observed in restored soils, whereas QE enantiomers exhibited comparable transformation rates in native soils. The second-round enantioselective transformation of rac-QE was altered by the first-round transformation of enantiopure quizalofop-P-ethyl (R-P-QE) in restored and native soils through selective effects of R-P-QE on the bacterial community. The transformation rate of rac-QE was predominantly determined by bacterial abundance and richness, while the enantioselectivity was correlated more with bacterial structure.

A Microbiome Study Reveals Seasonal Variation in Endophytic Bacteria Among different Mulberry Cultivars

Knowledge of seasonal shifts in the bacterial community composition among different mulberry (Morus L.) cultivars will facilitate to develop the biocontrol phytopathogens strategy using endophytic bacteria. The present study investigated the endophytic bacterial communities of four mulberry cultivars that have different resistance to mulberry fruit sclerotiniosis using Illumina-based sequencing of the 16S rRNA gene fragment in spring and autumn. The results indicated that spring samples harbor higher bacterial operational taxonomic units (OTUs), α-diversity, and bacterial community complexity in comparison with autumn samples. The taxonomic composition analysis showed that the majority of endophytes were composed of Proteobacteria (genus level: Methylobaterium) and Actinobacteria in spring, while sequences classified as Proteobacteria (genus level: Pantoea and Pseudomonas) were abundant in autumn. Analysis of β-diversity also revealed endophytic bacteria were divided into two main groups by season. By comparison among different mulberry cultivars, we found that Pantoea, Methylobaterium, and Pseudomonas were the three major bacterial genera in all cultivars, while their relative abundances varied with cultivars and appeared no obvious relationship with resistance level of mulberry fruit sclerotiniosis. The complex correlation of the endophytic communities in susceptible mulberry cultivars was higher than that of the resistant cultivars. Overall, the findings suggested that season plays a key role in determining the mulberry endophytic bacterial communities, followed by host cultivar, and Proteobacteria was the predominant phylum in both seasons and different mulberry cultivars.

Changes in microbial communities during the removal of natural and synthetic glucocorticoids in three types of river-based aquifer media.

Glucocorticoids in sewage treatment plant effluent discharged into rivers could influence microbial community structure in river-based aquifer media and affect groundwater quality. The effect of representative natural and synthetic glucocorticoids, namely, hydrocortisone (CRL) and dexamethasone (DEX), on the microbial communities in three types of river-based aquifer media was evaluated. The aquifer media was taken from the Beijing Chaobai River (BJ), Hebei Hutuo River (HB), and Tianjin Duliujian River (TJ) and they exhibited different physicochemical and biological properties. The attenuation rates of CRL were 0.175, 0.119, and 0.096day-1 and for DEX were 0.222, 0.151, and 0.113day-1 in the media from BJ, HB, and TJ, respectively. All the attenuation rates followed first-order kinetics. The biodiversity decreased significantly with CRL and DEX amendment. The microbial community composition differed in relation to the type of aquifer media and glucocorticoids, especially for BJ at the phylum level. In BJ, the major bacterial genus was Bacillus and in HB it was Rhodobacter. However, in TJ, three bacterial genera (Methylophilus, Methylobacillus, and Methylotenera) and Candidatus_Nitrososphaera were predominant in the microflora. All these genera were able to degrade both CRL and DEX. Distance-based redundancy analysis revealed that total organic carbon (TOC), the type of glucocorticoid, and the pH were the main factors explaining the variations in microbial community composition.

Hydrocortisone biotransformation pathway in three types of river-based aquifers media and changes in microbial community

The biodegradation characteristics and primary metabolic pathway of hydrocortisone were investigated in different aquifer media-water systems. The aquifer media from Beijing Chaobai river (BJ), Hebei Hutuo river (HB), and Tianjin Duliujian river (TJ), having different properties were used. The results showed that the attenuation rates of hydrocortisone were 0.175, 0.119 and 0.096 d−1 in BJ, HB, TJ respectively and all of them followed the first-order rate kinetics. The main metabolic pathway of hydrocortisone in the BJ system began with the hydration of C-4 and C-5 double bond on ring A, and the A-ring was subsequently cleaved. In the case of the HB system, the primary biotransformation pathway started from the side chain degradation and oxidation of C-12 on ring D to form a ketone group, and the D-ring was subsequently carboxylated and cleaved. The differences in attenuation rates and metabolic pathways were associated with community structures of bacteria and archaea in different systems. The biodegradation of A-ring had a greater influence on the decay rate than D-ring. The results from microbial community structure analysis using 454 pyrosequencing of 16s rRNA genes showed that the microbial community structure transformed to microflora with good degrading capacity towards hydrocortisone by hydrocortisone amendment. The potential bio-transformers were seven major bacterial genera (Methylophilus, Sphingopyxis, Arenimonas, hgcI_clade, Methylobacillus, Methylotenera and Fluviicola) and two major archaeal genera (Candidatus_Nitrososphaera and Woesearchaeota_DHVEG-6), respectively.

Microbial Communities and Sludge Specific Resistance in Two SBRs Treating Leachate

The relationship between microbial populations and sludge filtration performance was studied when active sludge was used to treat the leachate from municipal solid waste incineration plants. Two SBRs (SBR1 and SBR2) were operated at the same conditions, except that SBR1 was exposed to the sunlight and SBR2 was in the dark. To identify the difference in microbial populations in two reactors, high-throughput sequencing method was used. On the 50th day, the fungi abundance in SBR2 was higher than in SBR1. Phylum Rozellomycota became the dominant fungi in SBR1, whose relative abundance was 83.71%. Phylum Basidiomycota and Genus Trichosporon became only dominant fungi in SBR2, whose relative abundances were 99.84% and 99.78%, respectively. Bacterial abundance in SBR1 was higher than in SBR2. In SBR1, Thauera was the major bacterial genus, whose relative abundance was 39.35%. In SBR2, Planktosalinus, Thauera, and Ottowia were the major bacterial genera, whose relative abundances were 16.84%, 16.23%, and 12.55%. Rotifers and other predatory metazoan were detected on the 30th-50th days in SBR1 and sludge specific resistance began to decline on the 35th day. Filamentous fungi bulking caused by Trichosporon resulted in a continuous increase in sludge specific resistance of SBR2. The dominant microbial communities (especially fungi) and sludge specific resistances in SBR1 and SBR2 were very different because of the effect of sunlight. Therefore, sunlight plays an important role on microbial communities and sludge characteristics.

Rethinking anaerobic As(III) oxidation in filters: Effect of indigenous nitrate respirers

Microorganisms play a key role in the redox transformation of arsenic (As) in aquifers. In this study, the impact of indigenous bacteria, especially the prevailing nitrate respirers, on arsenite (As(III)) oxidation was explored during groundwater filtration using granular TiO2 and subsequent spent TiO2 anaerobic landfill. X-ray absorption near edge structure spectroscopy analysis showed As(III) oxidation (46% in 10 days) in the presence of nitrate in the simulated anaerobic landfills. Meanwhile, iron (Fe) species on the spent TiO2 were dominated by amorphous ferric arsenate, ferrihydrite and goethite. The Fe phase showed no change during the anaerobic landfill incubation. Batch incubation experiments implied that the indigenous bacteria completely oxidized As(III) to arsenate (As(V)) in 10 days using nitrate as the terminal electron acceptor under anaerobic conditions. The bacterial community analysis indicated that various kinds of microbial species exist in groundwater matrix. Phylogenetic tree analysis revealed that Proteobacteria was the dominant phylum, with Hydrogenophaga (34%), Limnohabitans (16%), and Simplicispira (7%) as the major bacterial genera. The nitrate respirers especially from the Hydrogenophaga genus anaerobically oxidized As(III) using nitrate as an electron acceptor instead of oxygen. Our study implied that microbes can facilitate the groundwater As oxidation using nitrate on the adsorptive media.

Helicobacter pylori-derived extracellular vesicles increased in the gastric juices of gastric adenocarcinoma patients and induced inflammation mainly via specific targeting of gastric epithelial cells

Evidence indicates that Helicobacter pylori is the causative agent of chronic gastritis and perhaps gastric malignancy. Extracellular vesicles (EVs) play an important role in the evolutional process of malignancy due to their genetic material cargo. We aimed to evaluate the clinical significance and biological mechanism of H. pylori EVs on the pathogenesis of gastric malignancy. We performed 16S rDNA-based metagenomic analysis of gastric juices either from endoscopic or surgical patients. From each sample of gastric juices, the bacteria and EVs were isolated. We evaluated the role of H. pylori EVs on the development of gastric inflammation in vitro and in vivo. IVIS spectrum and confocal microscopy were used to examine the distribution of EVs. The metagenomic analyses of the bacteria and EVs showed that Helicobacter and Streptococcus are the two major bacterial genera, and they were significantly increased in abundance in gastric cancer (GC) patients. H. pylori EVs are spherical and contain CagA and VacA. They can induce the production of tumor necrosis factor-α, interleukin (IL)-6 and IL-1β by macrophages, and IL-8 by gastric epithelial cells. Also, EVs induce the expression of interferon gamma, IL-17 and EV-specific immunoglobulin Gs in vivo in mice. EVs were shown to infiltrate and remain in the mouse stomach for an extended time. H. pylori EVs, which are abundant in the gastric juices of GC patients, can induce inflammation and possibly cancer in the stomach, mainly via the production of inflammatory mediators from gastric epithelial cells after selective uptake by the cells.

17α-Ethynylestradiol biodegradation in different river-based groundwater recharge modes with reclaimed water and degradation-associated community structure of bacteria and archaea

This study investigated 17α-ethynylestradiol (EE2) biodegradation process and primary metabolic pathways associated with community structures of microorganism during groundwater recharge using reclaimed water. The attenuation rate is 1.58 times higher in wetting and drying alternative recharge (WDAR) than in continual recharge (CR). The primary biotransformation pathways of EE2 in WDAR system began with the oxidation of C-17 on ring D to form a ketone group, and D-ring was subsequently hydroxylated and cleaved. In the CR system, the metabolic pathway changed from the oxidation of C-17 on ring D to hydroxylation of C-4 on ring A, and ring A or B subsequently cleaved; this transition was related to DO, and the microbial community structure. Four hundred fifty four pyrosequencing of 16s rRNA genes indicated that the bacterial communities in the upper layer of the WDAR system were more diverse than those found in the bottom layer of the CR system; this result was reversed for archaea. Unweighted UniFrac and taxonomic analyses were conducted to relate the change in bacterial community structure to the metabolic pathway. Microorganism community diversity and structure were related to the concentrations of dissolved oxygen, EE2 and its intermediates in the system. Five known bacterial classes and one known archaeal class, five major bacterial genera and one major archaeal genus might be involved in EE2 degradation. The findings of this study provide an understanding of EE2 biodegradation in groundwater recharge areas under different recharging modes and can facilitate the prediction of the fate of EE2 in underground aquifers.

Buried straw layer and plastic mulching increase microflora diversity in salinized soil

Salt stress has been increasingly constraining crop productivity in arid lands of the world. In our recent study, salt stress was alleviated and crop productivity was improved remarkably by straw layer burial plus plastic film mulching in a saline soil. However, its impact on the microflora diversity is not well documented. Field micro-plot experiments were conducted from 2010 to 2011 using four tillage methods: (i) deep tillage with plastic film mulching (CK), (ii) straw layer burial at 40 cm (S), (iii) straw layer burial plus surface soil mulching with straw material (S+S), and (iv) plastic film mulching plus buried straw layer (P+S). Culturable microbes and predominant bacterial communities were studied; based on 16S rDNA, bacterial community structure and abundance were characterized using denaturing gradient gel electrophoresis (DGGE) and polymerase chain reaction (PCR). Results showed that P+S was the most favorable for culturable bacteria, actinomyces and fungi and induced the most diverse genera of bacteria compared to other tillage methods. Soil temperature had significant positive correlations with the number of bacteria, actinomyces and fungi (P<0.01). However, soil water was poorly correlated with any of the microbes. Salt content had a significant negative correlation with the number of microbers, especially for bacteria and fungi (P<0.01). DGGE analysis showed that the P+S exhibited the highest diversity of bacteria with 20 visible bands followed by S+S, S and CK. Moreover, P+S had the highest similarity (68%) of bacterial communities with CK. The major bacterial genera in all soil samples were Firmicutes, Proteobacteria and Actinobacteria. Given the considerable increase in microbial growth, the combined use of straw layer burial and plastic film mulching could be a practical option for alleviating salt stress effects on soil microbial community and thereby improving crop production in arid saline soils.

Seasonal monitoring of bacteria and archaea in a full-scale thermophilic anaerobic digester treating food waste-recycling wastewater: Correlations between microbial community characteristics and process variables

Microbial population size, community structure, and diversity, and the correlations of these characteristics with process variables were investigated in samples taken seasonally over two years from a full-scale thermophilic anaerobic digester treating food waste-recycling wastewater (FRW). The organic component of the FRW consisted of carbohydrate (35% of volatile solids), protein (34%) and lipid (30%). The chemical oxygen demand (COD) removal efficiency of the anaerobic digestion (AD) system negatively correlated with Na+ (2.9–7.7g/L) and lipid (3.3–22.8g/L) concentrations, which varied significantly over the two years. Tepidanaerobacter, Anaerobaculum, Defluviitoga, Keratinibaculum, Gelria, Tepidimicrobium, Caldicoprobacter, Bacillus, and Syntrophaceticus were the major bacterial genera, and Methanoculleus and Methanobacterium were the major archaeal genera. Concentrations of Na+ and lipid in the digester were negatively correlated with total bacterial and archaeal populations determined by real-time quantitative PCR. These concentrations could also significantly affect the bacterial community structure (e.g., negative correlations with Gelria), but not archaeal community structure. Lipid concentration was negatively correlated with bacterial diversity, but was not correlated with archaeal diversity. Ammonia concentration in the digester (2.0–4.3gN/L) had no significant correlation with COD removal or total bacterial/archaeal populations, but could significantly affect both bacterial and archaeal community structures, including syntrophic acetate-oxidizing bacteria and hydrogenotrophic methanogens. These results indicate that Na+, lipid and ammonia are among the key parameters that affect the process performance of a thermophilic AD system treating FRW and/or the microbial communities in it.

Comparison of the Bacterial Microbiota in a Bale of Collected Cardboard Determined by 454 Pyrosequencing and Clone Library

Biofouling, the accumulation of microorganisms, is a major problem in paper mills processing paper and cardboard. This leads to the production of lower quality recycled products. Several studies have focused on the microbial content in the paper mill and the final products. Our aim was to determine the microbial biota in a bale of collected cardboard prior to entering the paper mill. Total genomic DNA was isolated and analyzed using two different methods for comparison purposes: 454 pyrosequencing and clone library. A total of 3268 V6-V8 454 pyrosequencing reads and 322 cloned V6-V8 16S rRNA nucleotide sequences were obtained. Both methods showed the presence of three major bacterial genera: Bacillus, Solibacillus and Paenibacillus, all members of the spore-forming phylum Firmicutes. Pyrosequencing, however, revealed a richer and more diverse bacterial community than clone library. It showed the presence of additional minor Firmicute genera and of a small number of Proteobacteria. The sorting at the recycling plant, the storing, and the processing at the paper mill, the end uses, will all contribute to the bacterial microbiota present in a bale of collected cardboard as revealed here.

Sequence-based analysis of the bacterial and fungal compositions of multiple kombucha (tea fungus) samples

Kombucha is a sweetened tea beverage that, as a consequence of fermentation, contains ethanol, carbon dioxide, a high concentration of acid (gluconic, acetic and lactic) as well as a number of other metabolites and is thought to contain a number of health-promoting components. The sucrose–tea solution is fermented by a symbiosis of bacteria and yeast embedded within a cellulosic pellicle, which forms a floating mat in the tea, and generates a new layer with each successful fermentation. The specific identity of the microbial populations present has been the focus of attention but, to date, the majority of studies have relied on culture-based analyses. To gain a more comprehensive insight into the kombucha microbiota we have carried out the first culture-independent, high-throughput sequencing analysis of the bacterial and fungal populations of 5 distinct pellicles as well as the resultant fermented kombucha at two time points. Following the analysis it was established that the major bacterial genus present was Gluconacetobacter, present at >85% in most samples, with only trace populations of Acetobacter detected (<2%). A prominent Lactobacillus population was also identified (up to 30%), with a number of sub-dominant genera, not previously associated with kombucha, also being revealed. The yeast populations were found to be dominated by Zygosaccharomyces at >95% in the fermented beverage, with a greater fungal diversity present in the cellulosic pellicle, including numerous species not identified in kombucha previously. Ultimately, this study represents the most accurate description of the microbiology of kombucha to date.

Human milk oligosaccharide consumption by intestinal microbiota

Human milk oligosaccharides (HMO) constitute the third most abundant class of molecules in breast milk. Since infants lack the enzymes required for milk glycan digestion, this group of carbohydrates passes undigested to the lower part of the intestinal tract, where they can be consumed by specific members of the infant gut microbiota. We review proposed mechanisms for the depletion and metabolism of HMO by two major bacterial genera within the infant intestinal microbiota, Bifidobacterium and Bacteroides.

Differences between the normal vaginal bacterial community of baboons and that of humans

Humans and baboons (Papio spp.) share considerable anatomical and physiological similarities in their reproductive tracts. Given the similarities, it is reasonable to expect that the normal vaginal microbial composition (microbiota) of baboons would be similar to that of humans. We have used a 16S rRNA phylogenetic approach to assess the composition of the baboon vaginal microbiota in a set of nine animals from a captive facility and six from the wild. Results show that although Gram-positive bacteria dominate in baboons as they do in humans, there are major differences between the vaginal microbiota of baboons and that of humans. In contrast to humans, the species of Gram-positive bacteria (Firmicutes) were taxa other than Lactobacillus species. In addition, some groups of Gram-negative bacteria that are not normally abundant in humans were found in the baboon samples. A further level of difference was also seen even within the same bacterial phylogenetic group, as baboon strains tended to be more phylogenetically distinct from human strains than human strains were with each other. Finally, results of our analysis suggests that co-evolution of microbes and their hosts cannot account for the major differences between the microbiota of baboons and that of humans because divergences between the major bacterial genera were too ancient to have occurred since primates evolved. Instead, the primate vaginal tracts appear to have acquired discrete subsets of bacteria from the vast diversity of bacteria available in the environment and established a community responsive to and compatible with host species physiology.

Polyphasic Taxonomy of Novel Actinobacteria Showing Macromolecule Degradation Potentials in Bigeum Island, Korea

Aerobic, alkaliphilic to alkalitolerant and mesophilic bacteria were isolated and characterized from soil and sediment samples collected from Bigeum Island, South Korea. The total numbers of microorganisms in the soil and sediment samples were found to be 10(3)-10(5) cfu/g and 10(2)-10(7) cfu/g, respectively. A total of 163 isolates were isolated and subjected to further characterization on the basis of pH, temperature and salt tolerance. Among the 163 isolates, 54 were selected based on their tolerance attributes to temperature, pH and NaCl. Out of the 54 isolates, 27 were further selected based on their multiple tolerance ability and enzyme profile and were subjected to 16S rRNA gene sequencing and phylogenetic analysis. The latter indicated that most of the Bigeum Island isolates were related to the phylum Actinobacteria. The phylogenetic tree based on 16S rRNA gene sequences placed the 27 isolates into 9 different major bacterial genera, each genus comprising pure cultures that shared < or =97% sequence identity and 18 putative novel species. Most of the strains were alkalitolerant and mesophilic, and produced biotechnologically important enzymes at alkaline pH.

Selection of psychrotrophic Leuconostoc spp. producing highly active dextransucrase from lactate fermented vegetables

Leuconostoc is the major bacterial genus in the initial phase of the lactate fermentation of vegetables. The dextransucrase elaborated from this bacterium is used to synthesize dextran polymers or prebiotic oligosaccharides. To use Leuconostoc as a starter culture in the manufacture of the kimchi-like fermented foods at low temperature, we isolated microbial flora that showed fast growth rates and high enzyme activity under the test conditions. Nine hundred colonies of Leuconostoc were collected from kimchi, sauerkraut, and pickled cucumber using three consecutive selection media; after batch culture and enzyme activity assays, four strains were selected. Sequencing of 16S rRNA genes of the strains revealed that HJ-S7 and HJ-S13 were Leuconostoc ( Ln.) mesenteroides and HJ-P4 and HJ-P5 were Ln. citreum. When compared to the type strain, Ln. mesenteroides B-512F, HJ-P4 showed a more than twofold faster growth rate and 20-fold higher enzyme activity during cultivation at 8 °C. These strains are suitable as oligosaccharide-synthesizing starters for the fermentation of not only kimchi but also sauerkraut and pickled cucumbers.

Interrelation between taxis and sporulation systems

There are several hypotheses concerning the mechanism initiating sporulation and germination in bacteria. Here an account of current knowledge on the subject is given and a hypothesis is suggested, according to which chemotaxis and initiation of both sporulation and germination are governed by a common system. Chemotaxis and sporulation are two distinct behavioral systems of the Baciflus genera. Chemotaxis directs migration of cells to a favorable environment or away from harmful substances. Sporulation as a behavioral system is initiated in response to a deterioration of the external conditions and allows bacteria to survive during the unfavorable period. In the terms of chemotaxis, sporulation is a response to an increase in repellent concentrations or a decrease in attractant concentrations. The set of chemoeffectors for taxis and sporulation are very similar, the most common being amino acids and sugars. I suggest that the information concerning the outer medium (changes in chemoeffector concentrations) which is sensed by specific receptors, summed up and processed by the taxis system is transmitted not only to flagella, but to the sporulation system as well. Ordinarily, only the taxis system operates, but a certain critical increase in repellent concentration (or a decrease in attractant concentration) would trigger the sporulation system; accordingly, increase in attractant concentration would initiate germination. In analyzing the interrelationship between taxis and sporulation, we shall consider data obtained not only for Bacillus subtilis chemotaxis but also in studies of Escherichia coli chemotaxis, supposing that the mechanism of chemotaxis is basically similar in different bacterial species. Indeed, the main steps of information processing during taxis: reception, methylation of MCP proteins (methylaccepting chemotaxis proteins), Ca2+-regulated flagellar reversals were found to be alike in all major bacterial genera [3,14,28,30,35].