Strain M1 Research Articles

Epidemiology of Serratia marcescens infections in NICU of a Teaching and Research Hospital in Northern Italy.

Serratia marcescens (Sm) is a known cause of infection and colonization in neonates receiving intensive care. The aim of this study was to identify the risk factors for colonization and infection with Sm in Neonatal Intensive Care Unit (NICU) of a tertiary care Hospital. A case-control study was conducted from January to December 2011 in neonates admitted to the NICU. Cases are patients with a microbiologically confirmed infection or colonization, controls were randomly chosen among patients admitted to the same NICU. Globally, 39 acquired infections or colonizations were identified. Among factors related to pregnancy, only premature delivery was independently associated to the risk of infection; as well as mechanical ventilation and catheterization for parenteral nutrition, considering indwelling devices. Prolonged administration with antibiotics were also related to the risk of infection. Among Sm strains which have been tested to antibiotics, all have been resistant to amoxicillin/clavulanic acid and to colistin. This study confirms the association between Sm infection or colonization and low gestational age. Invasive medical devices and medications, strictly necessary in care-support of preterm neonates, are likely related to Sm infection too. Preventive control strategies are expected to be effective in the control of Sm spread in NICUs.

Identification of Molecular Markers for Early Detection of Sluggish Fermentation Associated with Heat Shock during Alcoholic Fermentation

Problematic fermentations frequently drive economic losses and logistic problems in the winemaking industry. Previous studies have determined thermal conditions leading to problematic fermentations, selecting two contrasting yeast strains for further transcriptomic analysis. Saccharomyces cerevisiae SBB11 showed strong thermosensitivity towards heat shock, while S. cerevisiae PDM was found to be thermotolerant. The aim of this study was to select genes with significantly upregulated expression to be later used as biomarkers for early detection of sluggish fermentation associated with heat shock. Candidate genes were selected from previously obtained RNA-seq data. Alcoholic fermentations were conducted with 4 S. cerevisiae strains SBB11, PDM, M2 and ICV D21. Heat shocks on day 3 of alcoholic fermentation were applied at 36 and 40 °C for 16 h. S. cerevisiae cells were collected at different times after heat shock onset for qPCR analysis of candidate gene expression over time. Three genes showed promising results; SSA1, MGA1 and OPI10 significantly increased expression with respect to the control. The selected genes showed increased expression during the first 9 h post heat shock and are proposed for early detection of sluggish fermentations associated with heat shock.

Biocontrol Using Pythium oligandrum during Malting of Fusarium-Contaminated Barley

This study investigates the potential of Pythium oligandrum (strains M1 and 00X48) as a biocontrol agent in suppressing the growth of Fusarium culmorum and the production of mycotoxins during the malting of naturally contaminated barley (Hordeum vulgare). The effects of the biocontrol agent on F. culmorum-infected barley malt (BM) were evaluated through real-time PCR and its impact on mycotoxin production was determined by quantitative analysis of deoxynivalenol (DON) and deoxynivalenol-3-glucoside (D3G). The effect of treatment on BM and beer quality were also determined through European Brewery Convention (EBC) standard methods. Optimal treatment with P. oligandrum strains M1 and 00X48 yielded a 59% and 48% reduction in F. culmorum contamination, by 37% and 17% lower DON, and 27% and 32% lower D3G, respectively. BM treated with both P. oligandrum strains exhibited quality enhancement; beer produced from the BM treated with P. oligandrum strain M1 resulted in no quality deterioration and with 26% and 18% less DON and D3G, respectively, transferred to the final product.

The transcriptomic response of Hyphantria cunea (Drury) to the infection of Serratia marcescens Bizio based on full-length SMRT transcriptome sequencing.

Hyphantria cunea (Drury) is a globally important forest pest. We found that the Serratia marcescens Bizio strain SM1 had insecticidal activity against H. cunea, but the transcriptomic response of H. cunea to SM1 were not clear. Therefore, we performed full-length sequencing of the transcriptomes of H. cunea larvae infected with SM1 and the control group. A total of 1,183 differentially expressed genes (DEGs) were identified by comparing the group infected with SM1 and the control group, including 554 downregulated genes and 629 upregulated genes. We found many downregulated genes in metabolic pathways. Furthermore, some of these downregulated genes were involved in cellular immunity, melanization, and detoxification enzymes, which showed that SM1 weakened H. cunea immunity. In addition, genes in the juvenile hormone synthesis pathway were upregulated, which was detrimental to the survival of H. cunea. This research analyzed the transcriptomic response of H. cunea to SM1 by high-throughput full-length transcriptome sequencing. The results provide useful information to explore the relationship between S. marcescens and H. cunea, and theoretical support for the application of S. marcescens and the control of H. cunea in the future.

Degradation Characteristics and Remediation Ability of Contaminated Soils by Using β-HCH Degrading Bacteria.

Three degradation strains that can utilize β-Hexachlorocyclohexanes (β-HCH) as the sole carbon source were isolated from the soil substrate of constructed wetland under long-term β-HCH stress, and they were named A1, J1, and M1. Strains A1 and M1 were identified as Ochrobactrum sp. and strain J1 was identified as Microbacterium oxydans sp. by 16S rRNA gene sequence analysis. The optimum conditions for degradation with these three strains, A1, J1, and M1, were pH = 7, 30 °C, and 5% inoculum amount, and the degradation rates of 50 μg/L β-HCH under these conditions were 58.33%, 51.96%, and 50.28%, respectively. Degradation characteristics experiments showed that root exudates could increase the degradation effects of A1 and M1 on β-HCH by 6.95% and 5.82%, respectively. In addition, the degradation bacteria A1 and J1 mixed in a ratio of 1:1 had the highest degradation rate of β-HCH, which was 69.57%. An experiment on simulated soil remediation showed that the compound bacteria AJ had the best effect on promoting the degradation of β-HCH in soil within 98 d, and the degradation rate of β-HCH in soil without root exudates was 60.22%, whereas it reached 75.02% in the presence of root exudates. The addition of degradation bacteria or degradation bacteria-root exudates during soil remediation led to dramatic changes in the community structure of the soil microorganisms, as well as a significant increase in the proportion of aerobic and Gram-negative bacterial groups. This study can enrich the resources of β-HCH degrading strains and provided a theoretical basis for the on-site engineering treatment of β-HCH contamination.

Improving radish phosphorus utilization efficiency and inhibiting Cd and Pb uptake by using heavy metal-immobilizing and phosphate-solubilizing bacteria

Phosphate-solubilizing bacteria play a key role in increasing plant growth as potential suppliers of soluble phosphorus and have great potential for the remediation of heavy metal-polluted soils. However, the soil and microbiological mechanisms by which phosphate-solubilizing bacteria prevent heavy metal absorption in radish have not been adequately studied. Here, the mechanisms of phosphorus solubilization, Cd and Pb immobilization, and the inhibition of heavy metal absorption by phosphate-solubilizing bacteria were studied in radish through solution adsorption and pot experiments. Two phosphate-solubilizing bacteria with high Cd and Pb removal rates (46.9–97.12 %), Klebsiella sp. M2 and Kluyvera sp. M8, were isolated. The soluble phosphorus content released by strains M2 and M8 was 265–277 mg L−1, achieved by secreting oxalic acid, ascorbic acid, citric acid, and succinic acid in an inorganic phosphorus medium containing 3 mg L−1 Cd and 5 mg L−1 Pb. Furthermore, these two functional strains induced the formation of Pb2(PO4)2, Cd(PO3)2, Fe2Pb3(PO4)2, CdS, and PbS precipitates that immobilized Cd and Pb in the solution. In general, strains M2 and M8 inhibited the absorption of Cd and Pb by radish by the following mechanisms: i) bacterial cell wall adsorption, ii) induction of Pb2(PO4)2, Cd(PO3)2, Fe2Pb3(PO4)2, CdS, and PbS precipitation in the solution/soil, iii) increases in the Ca2P and FeP contents in the radish rhizosphere, and iv) the promotion of bacterial community enrichment toward phosphorus-solubilizing and plant growth-promoting properties (Ramlibacter, Enterobacter, Bacillus, Gemmatimonas, and Lysinibacillusin) in the radish rhizosphere. These results provide bacterial resources and technical approaches to heavy metal pollution amelioration and efficient phosphorus fertilizer use in farmland.

Bactericidal effect of lascufloxacin on HEp-2 cell-internalized group A Streptococcus

IntroductionAlthough amoxicillin (AMPC) is recommended as first-line therapy for acute pharyngotonsillitis caused by group A streptococci (GAS), it often fails to eradicate infections. Internalization and subsequent intracellular survival of GAS are considered major mechanisms for penicillin therapeutic failure. It is, therefore, desirable to administer drugs that exert bactericidal effects on extracellular and intracellular GAS. In this study, we aim to investigate the bactericidal effects of lascufloxacin (LSFX) on internalized GAS in HEp-2 cells. Materials and methodsThe GAS strain M1 and clinical isolate strain #2 were used in this study. Following treatment of GAS-infected human pharyngeal carcinoma epithelial HEp-2 cells with LSFX or AMPC, internalized GAS cells were recovered. The concentrations of LSFX and AMPC were equivalent to 1 × and 2 × MIC for strain M1. Culture medium was used as a control. Time-lapse and fluorescence images of GAS invading HEp-2 cell were obtained. LIVE/DEAD fluorescence staining was used to confirm the viability of internalized GAS. ResultsLSFX significantly reduced the number of cell-internalized M1 and #2 GAS strains compared to the control (p < 0.01) in a dose-dependent manner. However, AMPC did not reduce this in both strains. Both live and dead intracellular GAS were confirmed in HEp-2 cells exposed to LSFX. In contrast, intracellular GAS survived in HEp-2 cells exposed to AMPC and in the control. ConclusionLSFX elicits significant bactericidal effects on cell-internalized GAS, hence it may represent a potent therapeutic option for patients with acute pharyngotonsillitis in whom AMPC treatment has failed.

Impacts of a bacterial algicide on metabolic pathways in Chlorella vulgaris

Chlorella is a dominant species during harmful algal blooms (HABs) worldwide, which bring about great environmental problems and are also a serious threat to drinking water safety. Application of bacterial algicides is a promising way to control HABs. However, the identified bacterial algicides against Chlorella and the understanding of their effects on algal metabolism are very limited. Here, we isolated a novel bacterium Microbacterium paraoxydans strain M1 that has significant algicidal activities against Chlorella vulgaris (algicidal rate 64.38 %, at 120 h). Atrazine-desethyl (AD) was then identified from strain M1 as an effective bacterial algicide, with inhibition or algae-lysing concentration values (EC50) of 1.64 μg/mL and 1.38 μg/mL, at 72 h and 120 h, respectively. LAD (2 μg/mL AD) or HAD (20 μg/mL AD) causes morphology alteration and ultrastructure damage, chlorophyll a reduction, gene expression regulation (for example, psbA, 0.05 fold at 24 h, 2.97 fold at 72 h, and 0.23 fold of the control in HAD), oxidative stress, lipid oxidation (MDA, 2.09 and 3.08 fold of the control in LAD and HAD, respectively, at 120 h) and DNA damage (average percentage of tail DNA 6.23 % at 120 h in HAD, slight damage: 5∼20 %) in the algal cells. The impacts of AD on algal metabolites and metabolic pathways, as well as the algal response to the adverse effects were investigated. The results revealed that amino acids, amines, glycosides and urea decreased significantly compared to the control after 24 h exposure to AD (p < 0.05). The main up-regulated metabolic pathways implied metabonomic resistance and defense against osmotic pressure, oxidative stress, photosynthesis inhibition or partial cellular structure damage, such as phenylalanine metabolism, arginine biosynthesis. The down-regulated glycine, serine and threonine metabolism is a major lead in the algicidal mechanism according to the value of pathway impact. The down-regulated glycine, and serine are responsible for the downregulation of glyoxylate and dicarboxylate metabolism, aminoacyl-tRNA biosynthesis, glutathione metabolism, and sulfur metabolism, which strengthen the algae-lysing effect. It is the first time to highlight the pivotal role of glycine, serine and threonine metabolism in algicidal activities, which provided a new perspective for understanding the mechanism of bacterial algicides exerting on algal cells at the metabolic level.

In Vivo Pathogenicity of Methicillin-Susceptible Staphylococcus aureus Strains Carrying Panton-Valentine Leukocidin Gene.

Toxin-producing Staphylococcus aureus strains posing a potential risk for public health have long been a topic of scientific research. Effects of Panton-Valentine leukocidin (PVL) on tissue destruction mechanisms and activities of inflammatory cells were presented in animal models of pneumonia and skin infections induced by PVL-producing S. aureus strains. This study aimed to demonstrate the in vivo pathogenicity of PVL-producing S. aureus strains isolated from some foodstuffs, which can be a potential risk to public health. PVL-positive methicillin-susceptible S. aureus (MSSA) strains M1 and YF1B-b isolated from different foodstuffs and a PVL-positive MSSA strain HT480 (positive control) were administered to New Zealand rabbits. Blood samples were harvested three and six hours after the intratracheal inoculation. Lung tissue samples were collected for gross and microscopic exams and immunohistochemical (IHC) demonstration of IL-6, IL8, IL-10, and TNF-α expressions. Serum cytokine levels were also measured by ELISA. The strains isolated from lung tissue samples were confirmed by pulsed-field gel electrophoresis. The development of acute necrotising pneumonia and a significant elevation in IL-6, IL-8, IL-10, and TNF-α expressions demonstrated the significance of foodborne PVL-positive MSSA strains in public health for the first time.

Biodefluorination of Perfluorooctanesulphonate by Ensifer adhaerens M1

A strain of bacteria M1, defluorinating perfluorooctanesulfonic acid (PFOS), was isolated from soil taken from the territory for testing fire extinguishing agents. The analysis of cultural, morphological, physiological and biochemical characters, the 16S rRNA gene sequencing allowed us to identify strain M1 as Ensifer adhaerens. The uniquely skill of the isolated strain to utilize PFOS in a mineral liquid medium for 5 days of cultivation was shown. It was found that E. adhaerens M1 transforms perfluorooctanesulfonic acid into perfluoroheptanoic acid, releasing 152 mg/L of free fluoride ions from 1,000 mg/L of PFOS. The data obtained allow us to recommend E. adhaerens M1 as potential treatment agent of the environment from organofluorine compounds.

Differences in adsorption, transmembrane transport and degradation of pyrene and benzo[a]pyrene by Bacillus sp. strain M1

In a previous study our group identified Bacillus sp. strain M1 as an efficient decomposer of high molecular weight-polycyclic aromatic hydrocarbons (HMW-PAHs). Interestingly, its removal efficiency for benzo[a]pyrene (BaP) was nearly double that of pyrene (Pyr), which was the reverse of what is reported for most other species. Here we compared the differential steps of biosorption, transmembrane transport and biodegradation of Pyr and BaP by strain M1 in order to assist in targeted selection of dominant strains and their degradation efficiency in the remediation of these two HMW-PAHs. The overall biosorption efficiency for BaP was 19% higher than that for Pyr, and the time needed to reach BaP peak adsorption efficiency was 4 days shorter than for Pyr. Transmembrane transport of the PAHs was compared in presence of sodium azide which inhibits ATP synthesis and metabolism. This indicated that both Pyr and BaP entered the cells by the same means of passive transport. Biodegradation of Pyr and BaP did not differ in the early stage of culture, but around days 5–7, the biodegradation efficiency of BaP was significantly (30–61%) higher than that of Pyr. Key enzymes involved in these processes were identified and their activity differed, with intracellular gentisate 1,2-dioxygenase and extracellular polyphenol oxidase as likely candidates to be involved in BaP degradation, while intracellular catechol-1,2- dioxygenase and salicylate hydroxylase are more likely involved in Pyr degradation. These results provide new insights for sustainable environmental remediation of pyrene and benzo(a)pyrene by these bacteria.

Enhancement of Wheat Growth by UV-Mutagenesis of Potential Chromium Tolerant Bacillus sp. Strain SR-2-1/1

UV mutagenesis has long been known to improve bacterial strains in their physiological capacity. In the current study, we used the UV mutagenesis approach to increase the PGPR characteristics of a pre-characterized metal-tolerant PGPR strain Bacillus sp. strain SR-2-1/1 (KY315919), with the objective of increasing the physiological outcome of its PGPR traits in vitro and post inoculation on wheat plants. After UV irradiation, the results implied a substantial in vitro increase in the phosphate solubilization and ammonia production of two selected mutant strains (M1 and M2) as compared to the wild-type strain SR-2-1/1; however, the ACC deaminase enzyme activity was completely lost in the mutant strains, which were originally present in the wild-type strains. However, the UV mutagenesis did not affect the taxonomy of these mutant strains. Moreover, the mutant strains M1 and M2 survived in the rhizosphere of wheat plants up to 30 days at an optimum (approximately 7–7.5 Log CFU/mL of rhizosphere soil) population density. The fresh and dry biomass, as well as root and shoot length, of wheat plants inoculated with one of the mutant strains M2 were significantly higher than in the wheat plants inoculated with wild-type strain SR-2-1/1. The overall results imply that the resulted mutant M2 was a physiologically competent PGPR strain, which could be tested in field experiments as an inoculum.

Effect of Lacticaseibacillus rhamnosus and Lactiplantibacillus plantarum isolated from food and human origin on reduction of IgE-dependent hypersensitivity in Balb/c mice

Capacity and ability of Lactiplantibacillus plantarum and Lacticaseibacillus rhamnosus probiotic strains isolated from some human and food sources were evaluated for modulating and regulating the immune system against hypersensitivity type 1 (dependent on IgE). In this study, given the probiotic properties of the strains and the use of mouse models, the strains were orally administered (1×109 cfu/ml) during 45 days with gavage needles. Levels of total IgE antibodies, cytokines TGF-β, INF-ɤ, and IL-4 were measured by ELISA and compared with control groups. In addition, the nasopharyngeal lavage (total and differential count) was evaluated. Among the strains, Lactiplantibacillus plantarum a7 and Lacticaseibacillus rhamnosus M1 had the highest suppression of IL-4 cytokine production in splenocytes from ovalbumin-sensitized mice in vitro. Also, a7 and M1 had a significant (P < 0.0001) effect on reducing total IgE levels compared to the control group (OVA). Further, Lactiplantibacillus plantarum M8, a7 and M1 enhanced the production of INF-ɤ and TGF-β cytokines. Examination of nasal lavage results revealed that the total cell count in the a7, M1 and Lacticaseibacillus rhamnosus RHM groups and eosinophil cells in Lactiplantibacillus plantarum LF57, a7, and M1 significantly decreased compared to the control group. It was observed oral feeding of the isolated strains had a beneficial effect on reducing the total count on Plate Count Agar (PCA) and Mac Conkey Agar in mice feces during 7 days. M1 and a7 showed the highest level of Lactic Acid Bacteria at 7.28 and 6.9 Log cfu/g on day14, respectively. In conclusion, the animals that received the strains M1 and a7 (isolated from cow's milk and infant's small intestine) had the highest count of lactic acid bacteria in the mice gastrointestinal tract on day 14 (7.28 and 6.9 Log cfu/g), respectively. In addition, the mentioned strains can modulate immune system of mice by suppressing IL-4 production, increasing INF-ɤ and TGF-β cytokines, and reducing total IgE levels.

ANTIBIOTIC SENSITIVITY OF LACTOBACILLI ISOLATED FROM DIFFERENT SOURCES IN THE ODESA REGION

Recently, possible co-application of probiotics and antibiotics has been widely discussed. This form of combined therapy, because of its commonly recognised advantage, is widely used to prevent antibiotic-associated diarrhoea and induced dysbiosis. Due to the increased application of lactobacilli as probiotics, EFSA has developed a number of requirements concerning their safety and functionality. Every commercial probiotic should be able to obtain the Qualified Presumption of Safety status (QPS). Though QPS is a status attributed to species, individual species differ greatly in their genome content, including those belonging to the genus Lactobacillus. Infectious bacteria and strains that may possess genes responsible for virulence or antibiotic resistance should not be used lest pathogenic genes be passed on to other species. The human gastrointestinal tract, due to the immense amount of bacteria and the close contact between them, is a possible place for gene transfer. The main hazard is the transfer of antibiotic resistance determinants from commensal bacteria and the emergence of resistance to common microbial infections, which can prevent successful antibiotic treatment. A condition of using bacterial strains as probiotics is their safety, in particular, the absence of antibiotic resistance determinants. The purpose of the work was to determine the antibiotic sensitivity/resistance of lactobacilli isolated from different sources in the Odesa region. By the disc diffusion method, it has been determined how sensitive the 13 lactobacilli strains isolated from auto-fermented vegetables, raw meat, and newborn children’s gastrointestinal tract are to 15 antibiotics with different mechanisms of action. It has been established that the sensitivity/resistance depended on the strain and specific antibiotic. An obvious feature of the strains under study was their higher sensitivity to antibiotics that inhibited the synthesis of protein and nucleic acids, as opposed to antibiotics that affected the synthesis of the cell wall and cytoplasmic membrane. The results of the comprehensive research have allowed selecting the Lactobacillus spp. strains O1, B4, 175, M2, and M3 as the most promising for the creation of probiotic preparations.

STUDY OF MICROBIOLOGICAL INDICATORS AND TAXONOMICAL COMPOSITION OF MICROBIAL ASSOCIATION OF MILK WHEY

Interest in bioethanol has grown significantly in recent decades, not only as a solvent, antifreeze or feedstock for the production of a wide range of different organic compounds, but also, to some extent, as a biofuel. Bioethanol has the following advantages over gasoline: it is less polluting, decomposes easily, has a high octane number, and can use renewable raw materials for its production. The ever-growing demand for bioethanol requires the search for new substrates that are cheaper than grain or potatoes. As one of these substrates, it is recommended to use whey, the main carbohydrate of which is lactose. The purpose of the study: to study the microbiological indicators and taxonomic composition of the microbial community of whey. In the course of the study, the microbiological indicators and taxonomic composition of the microbial community of whey of Merke Cheese Factory LLP, Amiran LLP (whey), Stella Alpina LLP (cheese whey) were studied. From the serum samples, 3 strains of yeast and 1 strain of lactic acid bacteria were isolated. As a result of prespecies identification of cultures of yeasts and lactic acid bacteria, strains of GB and GT were identified as Kluyveromyces marxianus, strain M1 - Lactococcus lactis, A1 - Candida inconspicua. Key words: whey, bioethanol, yeast cultures, lactic acid bacteria, strain.

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.

Subspecies Classification and Comparative Genomic Analysis of Lactobacillus kefiranofaciens HL1 and M1 for Potential Niche-Specific Genes and Pathways.

(1) Background: Strains HL1 and M1, isolated from kefir grains, have been tentatively identified, based on their partial 16S rRNA gene sequences, as Lactobacillus kefiranofaciens. The two strains demonstrated different health benefits. Therefore, not only the genetic factors exerting diverse functionalities in different L. kefiranofaciens strains, but also the potential niche-specific genes and pathways among the L. kefiranofaciens strains, should be identified. (2) Methods: Phenotypic and genotypic approaches were employed to identify strains HL1 and M1 at the subspecies level. For the further characterization of the probiotic properties of both strains, comparative genomic analyses were used. (3) Results: Both strains were identified as L. kefiranofaciens subsp. kefirgranum. According to the COG function category, dTDP-rhamnose and rhamnose-containing glycans were specifically detected in the L. kefiranofaciens subsp. Kefirgranum genomes. Three unique genes (epsI, epsJ, and epsK) encoding glycosyltransferase in the EPS gene cluster, and the ImpB/MucB/SamB family protein encoding gene were found in HL1 and M1. The specific ability to degrade arginine via the ADI pathway was found in HL1. The presence of the complete glycogen metabolism (glg) operon in the L. kefiranofaciens strains suggested the importance of glycogen synthesis to enable colonization in kefir grains and extend survival under environmental stresses. (4) Conclusions: The obtained novel information on the potential genes and pathways for polysaccharide synthesis and other functionalities in our HL1 and M1 strains could be applied for further functionality predictions for potential probiotic screening.

Mechanism and kinetics of chlorpyrifos co-metabolism by using environment restoring microbes isolated from rhizosphere of horticultural crops under subtropics.

The indiscriminate use of organophosphate insecticide chlorpyrifos in agricultural crops causes significant soil and water pollution and poses a serious threat to the global community. In this study, a microbial consortium ERM C-1 containing bacterial strains Pseudomonas putida T7, Pseudomonas aeruginosa M2, Klebsiella pneumoniae M6, and a fungal strain Aspergillus terreus TF1 was developed for the effective degradation of chlorpyrifos. Results revealed that microbial strains were not only utilizing chlorpyrifos (500 mg L–1) but also coupled with plant growth-promoting characteristics and laccase production. PGP traits, that is, IAA (35.53, 45.53, 25.19, and 25.53 μg mL–1), HCN (19.85, 17.85, 12.18, and 9.85 μg mL–1), and ammonium (14.73, 16.73, 8.05, and 10.87 μg mL–1) production, and potassium (49.53, 66.72, 46.14, and 52.72 μg mL–1), phosphate (52.37, 63.89, 33.33, and 71.89 μg mL–1), and zinc (29.75, 49.75, 49.12, and 57.75 μg mL–1) solubilization tests were positive for microbial strains T7, M2, M6, and TF1, respectively. The laccase activity by ERM C-1 was estimated as 37.53, 57.16, and 87.57 enzyme U mL–1 after 5, 10, and 15 days of incubation, respectively. Chlorpyrifos degradation was associated with ERM C-1 and laccase activity, and the degree of enzyme activity was higher in the consortium than in individual strains. The biodegradation study with developed consortium ERM C-1 showed a decreased chlorpyrifos concentration from the 7th day of incubation (65.77% degradation) followed by complete disappearance (100% degradation) after the 30th day of incubation in the MS medium. First-order degradation kinetics with a linear model revealed a high k –day value and low t1/2 value in ERM C-1. The results of HPLC and GC-MS analysis proved that consortium ERM C-1 was capable of completely removing chlorpyrifos by co-metabolism mechanism.

Bioinformatics analysis of Klebsiella pneumoniae M1, from microbial flocculation resources

The synthesis of a microbial flocculant is strictly controlled by its genetic genes, which may be the result of the expression of flocculant genes in the microbial genome. The whole genome of Klebsiella pneumoniae M1 was sequenced for obtaining the mechanism of flocculant synthesis and exploring the mechanism of flocculant production by flocculant bacteria. Therefore, it provided a basis for molecular genetics and functional genomic analysis of flocculants production bacteria. In this way, the mechanism of flocculant production by flocculating bacteria can be better explored. The whole genome sequence of flocculant strain M1 was determined using advanced second generation (Illumina) and third generation (PacBio) sequencing, which was screened from wheat alcohol wastewater. The genes related to flocculant characteristics produced by strain M1 were analyzed for combining with the analysis of flocculant structure characteristics. According to the de novo assembly, a total of 5,511,794 bp clean reads were generated and assembled into 24 contigs. The GC content was up to 58.39%. The genome contained approximately 5383 genes, but 5348 genes had obvious biological functions. A total of 437 genes were involved in carbohydrate metabolism and had coding genes of five carbohydrate-related enzymes. This result indicated that there were functional genes closely related to polysaccharide production in M1 genome. The main metabolic process of flocculant strain Klebsiella pneumoniae M1 was closely related to the potential pathway of extracellular polysaccharide biosynthesis, in which five kinds of carbohydrate synthase genes were involved.

Seed Protection of Solanum lycopersicum with Pythium oligandrum against Alternaria brassicicola and Verticillium albo-atrum.

Pythium oligandrum, strain M1, is a soil oomycete successfully used as a biological control agent (BCA), protecting plants against fungal, yeast, and oomycete pathogens through mycoparasitism and elicitor-dependent plant priming. The not yet described Pythium strains, X42 and 00X48, have shown potential as BCAs given the high activity of their secreted proteases, endoglycosidases, and tryptamine. Here, Solanum lycopersicum L. cv. Micro-Tom seeds were coated with Pythium strains, and seedlings were exposed to fungal pathogens, either Alternaria brassicicola or Verticillium albo-atrum. The effects of both infection and seed-coating on plant metabolism were assessed by determining the activity and isoforms of antioxidant enzymes and endoglycosidases and the content of tryptamine, amino acids, and heat shock proteins. Dual culture competition testing and microscopy analysis confirmed mycoparasitism in all three Pythium strains. In turn, seed treatment significantly increased the total free amino acid content, changing their abundance in both non-infected and infected plants. In response to pathogens, plant Hsp70 and Hsp90 isoform levels also varied among Pythium strains, most likely as a strategy for priming the plant against infection. Overall, our results show in vitro mycoparasitism between Pythium strains and fungal pathogens and in planta involvement of heat shock proteins in priming.