Sp Strain Research Articles

Selective removal of the non-herbicidal (S)-enantiomer of dichlorprop from agricultural soil by an in-situ enriched consortium

Rac-dichlorprop [(R,S)-2-(2,4-dichlorophenoxy)propanoic acid], a commonly used chiral phenoxyalkanoic acid herbicide, is frequently detected in various environments, posing threats to human health and environmental safety. The (S)-enantiomer of dichlorprop shows a lower herbicidal activity but a higher toxicity as compared to the (R)-enantiomer of dichlorprop. It is of great importance to enantioselectively remove the non-herbicidal (S)-dichlorprop from the rac-dichlorprop in the application sites. In this study, the dissipation of (R)- and (S)-dichlorprop in an agricultural soil was investigated. We found that the dissipation rate of (S)-dichlorprop was higher than that of (R)-dichlorprop in an agricultural soil. Although the influences of different enantiomers of dichlorprop on soil bacterial community were not different, Sphingobium was significantly enriched in the (S)-dichlorprop-treated soil as compared to (R)-dichlorprop, indicating that Sphingobium species played important roles in the dissipation of (S)-dichlorprop. Furthermore, a bacterial consortium containing Sphingobium sp. strain SP-2 (enantioselectively transforming (S)-dichlorprop to 2,4-dichlorophenol) and Sphingopyxis sp. strain DP-21 (mineralizing 2,4-dichlorophenol), which synergistically mineralized the (S)-enantiomer of dichlorprop, was isolated from the agricultural soil. Bioaugmentation with the in-situ isolated consortium (strains SP-2 and DP-21) resulted in the enhanced removal of the non-herbicidal (S)-dichlorprop from the soil and in the adaptation of the inoculated degrading strains. This study offers new insights into the enhanced bioremediation of the non-herbicidal (S)-dichlorprop contaminated soils while simultaneously ensuring environmental safety and crop yield.

Molecular characterization of algerian strains of Blastocysts sp

RésuméIntroductionBlastocystis sp. est un protozoaire colonisant le tube digestif de l’Homme et de nombreux animaux et il est à ce jour le parasite le plus fréquemment retrouvé dans les selles humaines. Dans certains pays en développement, sa prévalence dans les populations étudiées peut dépasser 50 %. Sur le plan morphologique, les isolats de Blastocystis sp. trouvés chez différents hôtes sont très similaires. Cependant, ces mêmes isolats présentent entre eux une très grande diversité génétique et pas moins de 17 sous-types (ou génotypes) ont déjà été identifiés à partir de données moléculaires. Des études de génotypage ont été réalisées dans de nombreux pays à travers le monde et en particulier dans certains pays du pourtour méditerranéen comme la France, l’Espagne, l’Italie, la Turquie ou l’Égypte. En revanche, très peu de données de génotypage sont disponibles en Algérie. À cet effet, nous avons réalisé la présente étude dont le but était d’identifier et de génotyper Blastocystis dans des échantillons de selles humaines et animales.Patients et méthodesMille huit cent soixante-neuf (1 869) prélèvements de selles appartenant à un personnel de cuisine dans le cadre du contrôle médical périodique, à des sujets pour la fourniture d’un certificat médical requis pour le traitement d’un dossier de visa et à des patients atteints de troubles gastro-intestinaux ont été examinés. À côté des selles humaines, des échantillons d’animaux, dont 10 volailles, 2 bovins et 2 murins ont été examinés. Toutes les selles ont été soumises à un examen microscopique direct complété par des techniques de concentration et une coloration de Ziehl Neelsen modifiée. La caractérisation moléculaire de 39 isolats humains et 14 d’origine animale a été réalisée par le séquençage et les séquences obtenues comparées à celles disponibles auprès de GenBank. Le séquençage n’a été contributif que pour 30 souches humaines et 9 souches animales.RésultatsSur l’ensemble des échantillons humain examinés, 284 étaient positifs (15,19 %) avec une prévalence de 7,38 % pour le Blastocystis. Parmi les 30 souches ayant fait l’objet d’une caractérisation moléculaire, le ST3 était prédominant (15/30, 50 %) suivi de ST1 (10/30, 33,33 %) et en troisième position le ST2 (4/30, 13,33 %). Le ST4 n’a été identifié que chez un seul patient (1/30, 3,33 %). La corrélation entre le statut clinique et le sous-type de Blastocystis identifié a montré que le nombre de ST3 était élevé chez les sujets asymptomatiques (11/15, 73 %) comparativement aux sujets symptomatiques (4/15, 26,66 %), de même pour le sous-type ST1 (7/10, 70 % versus 3/10, 30 %). À l’inverse, le nombre de ST2 était plus élevé chez les sujets présentant des troubles gastro-intestinaux (3/4, 75 %). À côté des souches humaines nous avons génotypé 7 souches aviaires, 2 souches murines et 2 souches bovines. La caractérisation des souches aviaires a révélé 5 ST6 (71,42 %) et 2 ST7 (28, 57 %). Les souches murines et bovines sont identifiées en tant que ST7 et ST6 respectivement.

Exploration of anti-chromium mechanism of marine Penicillium janthinellum P1 through combinatorial transcriptomic analysis and WGCNA

Fungi have a promising application prospect in the remediation of heavy-metal wastewater pollution which is a sticky global problem. New marine-derived strain Penicillium janthinellum P1 is of high chromium resistance. However, a comprehensive study of the transcriptomics in Penicillium janthinellum P1 strains is lacking. Firstly, the changing trends of a series of physiological and biochemical indices of P1 strain at 0 M and 1 M Cr concentration were investigated to track the ROS variation. Secondly, transcriptome sequencing of P1 was performed by RNA-Seq sequencing technology. The transcriptome data indicated that 12,352 coding protein regions were predicted, and 6655 differentially expressed genes were identified by DESeq2, of which 4234 genes were up-regulated, and 2421 genes down-regulated. Through further co-expression network of WGCNA analysis, the filtered unigenes were clustered into 19 modules. Combined with the physiological and biochemical findings, the three modules with the highest correlation with the six traits were selected to construct the network, and 52 hub genes were obtained. Furthermore, 10 speculative hub genes related to chromium resistance were selected and verified by real-time PCR. The results were in line with the expected experimental assumption. These results improve our understanding of the transcriptomic dimensions of the high chromium resistance of Penicillium janthinellum P1 strains.

Comprehensive pan-genomic, resistome and virulome analysis of clinical OXA-48 producing carbapenem-resistant Serratia marcescens strains

BackgroundCarbapenem-resistant Enterobacteriaceae (CRE) have been thoroughly studied as the pathogens associated with hospital acquired infections. However, data on Serratia marcescens are not enough. S. marcescens is now becoming a propensity for its highly antimicrobial-resistant clinical infections. MethodsFour carbapenem-resistant S. marcescens (CR-SM) isolates were obtained from hospitalized patients through routine microbiological experiments. We assembled the isolates genomes using whole genome sequencing (WGS) and compared their resistome and virulome patterns. ResultsThe average length and CG content of chromosomes was 5.33 Mbp and 59.8%, respectively. The number of coding sequences (CDSs) ranged from 4,959 to 4,989. All strains had one single putative conjugative plasmid with IncL incompatibility (Inc) group. The strains harbored blaCTX-M-15, blaTEM-1 and blaSHV-134. All plamsids were positive for blaOXA-48. No blaNDM-1, blaKPC, blaVIM and blaIMP were identified. The blaSRT-2 and aac(6′)-Ic genes were chromosomally-encoded. Class 1 integron was detected in strains P8, P11 and P14. The Escher_RCS47 and Salmon_SJ46 prophages played major role in plasmid-mediated carraige of extended spectrum β-lactamases (ESBLs). The CR-SM strains were equipt with typical virulence factors of oppotunistic pathogens including biofilm formation, adhesins, secretory systems and siderophores. The strains did not have ability to produce prodigiosin but were positive for chitinase and EstA. ConclusionThe presence of conjugative plasmids harboring major β-lactamases within prophage and class 1 integron structures highlights the role of different mobile genetic elements (MGEs) in distribution of AMR factors and more specifically carbapenemases. More molecular studies are required to determine the status of carbapenem resistance in clinical starins. However, appropriate strategies to control the global dissemination of CR-SM are urgent.

Antibacterial activities of bacteria associated with marine sponges of Axinella sp. on Carbapenem-Resistant Acinetobacter Baumannii (CRAB)

Carbapenem-resistant Acinetobacter baumannii (CRAB) is a gram-negative bacillus that commonly causes nosocomial infection found in Indonesia. CRAB infection caused by Acinetobacter baumannii that is resistant to Carbapenem. Resistance occurred because bacteria that cause infections easily treated with antibiotics become difficult to treat due to the uncontrolled use of antibiotics. A. baumannii has been resistant against the carbapenem class of antibiotics; and therefore, antibiotics are required to be obtained from natural ingredients with optimal working power, such as from the marine sponges of Axinella sp. The purpose of this study was to determine the antibacterial activities of bacteria associated with marine sponges of Axinella sp. against CRAB. Bacteria associated with Axinella sp. were isolated by differential dilution and cultures on Zobell 2216E media. An antibacterial activity test was performed using the overlay method. The antibacterial activity test was carried out to determine the presence of inhibition zones. The test results showed the bacteria associated with a marine sponge of Axinella sp strain 3 KD had antibacterial activity against CRAB growth with the formation of an inhibition zone of 16 mm. The results of the catalase test and oxidase test depicted that the isolates belong to the family of Staphylococcaceae. Isolates bacteria associated with a marine sponge of Axinella sp. were potential antibacterial agents against CRAB growth.

Assembly of D1/D2 complexes of photosystem II: Binding of pigments and a network of auxiliary proteins.

Photosystem II (PSII) is the multi-subunit light-driven oxidoreductase that drives photosynthetic electron transport using electrons extracted from water. To investigate the initial steps of PSII assembly, we used strains of the cyanobacterium Synechocystis sp. PCC 6803 arrested at early stages of PSII biogenesis and expressing affinity-tagged PSII subunits to isolate PSII reaction center assembly (RCII) complexes and their precursor D1 and D2 modules (D1mod and D2mod). RCII preparations isolated using either a His-tagged D2 or a FLAG-tagged PsbI subunit contained the previously described RCIIa and RCII* complexes that differ with respect to the presence of the Ycf39 assembly factor and high light-inducible proteins (Hlips) and a larger complex consisting of RCIIa bound to monomeric PSI. All RCII complexes contained the PSII subunits D1, D2, PsbI, PsbE, and PsbF and the assembly factors rubredoxin A and Ycf48, but we also detected PsbN, Slr1470, and the Slr0575 proteins, which all have plant homologs. The RCII preparations also contained prohibitins/stomatins (Phbs) of unknown function and FtsH protease subunits. RCII complexes were active in light-induced primary charge separation and bound chlorophylls (Chls), pheophytins, beta-carotenes, and heme. The isolated D1mod consisted of D1/PsbI/Ycf48 with some Ycf39 and Phb3, while D2mod contained D2/cytochrome b559 with co-purifying PsbY, Phb1, Phb3, FtsH2/FtsH3, CyanoP, and Slr1470. As stably bound, Chl was detected in D1mod but not D2mod, formation of RCII appears to be important for stable binding of most of the Chls and both pheophytins. We suggest that Chl can be delivered to RCII from either monomeric Photosystem I or Ycf39/Hlips complexes.

Comparative resistome and virulome analysis of clinical NDM-1–producing carbapenem-resistant Enterobacter cloacae complex

The Enterobacter cloacae complex (ECC) are causatives of hospital-acquired infections. The antimicrobial resistance (AMR) and virulence profiling of ECC promotes our knowledge for their elimination in clinical settings. We assembled the whole genome of four clinical carbapenem-resistant ECCs and characterized their AMR and virulence profiles using whole genome sequencing. The chromosomes length scaled from minimum 3 949 952 bp (for P2) to maximum 4 976 575 bp (for P3). Strains P1 and P2 belonged to sequence type (ST)182. P3 and P4 belonged to ST477 and ST134, respectively. The blaCTX-M-15 gene was detected in P1 plasmid. P1 and P4 harboured the blaTEM-1 and blaOXA-1 genes. blaNDM-1 was found in P1, P3, and P4. No blaOXA-48, blaKPC, blaVIM, or blaIMP were identified. The plasmids were nontransferable and had IncFIB, IncFII, Col, and IncC incompatibility (Inc) groups . Class 1 integron was detected in all strains. Virulence genes related to biofilms, adhesins, siderophores (aerobactin, enterobactin, and salmochelin), intrinsic antimicrobial efflux pumps, secretory systems type I to VI, environmental and antibiotic stress response , outer membrane proteins, and heavy metal (copper, tellurite, arsenic, and zinc) resistance were found. The number of positive virulence factors was higher for P1 compared with other strains. The accumulation of AMR genes in Enterobacter spp. and their high endurance in hostile environments is a serious health problem. More genomic investigations are required to determine their AMR and virulence genetic reservoirs at the global level.

A novel L‐asparaginase from the symbiotic Enterobacter aerogenes isolated from Eucheuma sp.

This study was aimed to purify and characterize the enzyme L-asparaginase from endophytic microorganisms of Eucheuma sp. in Puntondo Island, South Sulawesi, Indonesia. Research stages were ammonium sulfate precipitation, dialysis, and Sephadex G-75 gel filtration chromatography and Sephadex CMC-50 ion-exchange chromatography matrices. The result of test activities of ammonium sulfate fraction showed the highest range of 40%–60% the activity value of 6.71 IU/ml. The highest protein content was obtained on a 0%–20% fraction of 2.76 mg/ml. Temperature and pH assessments indicated that L-asparaginase had optimum activity at 37°C and pH 8, respectively. At the stage of dialysis, the highest protein content was 5.17 IU/ml in a 0%–20% fraction, and the highest enzyme activity was 1.23 IU/ml in a 20%–40% fraction. The results of gel filtration chromatography fractions G-75 were F5–F10, with a specific activity of 0.60 U/mg, 2.05 times higher purity level than the crude extract enzyme. The results of CMC-50 ion-exchange chromatography showed that F54 and F55 fractions had a specific activity of 106.97 and 295.38 U/mg, respectively, with a purity level of 366.34 and 1,011.57 times higher than the crude extract enzyme. Novelty impact statement Enterobacter aerogenes strain P5, an endophytic bacterium from Eucheuma sp., can produce pure L-asparaginase enzyme with a high specific activity applied in pharmaceuticals nutraceutical applications.

Co-culture of microalga Chlorella sorokiniana with syntrophic Streptomyces thermocarboxydus in cassava wastewater for wastewater treatment and biodiesel production

This study aimed to conduct a co-culture of a microalga and syntrophic actinomycetes to treat cassava a biogas effluent wastewater and enhance biodiesel production. Streptomyces thermocarboxydus strain BMI 10 produced the greatest effect on biomass production by Chlorella sorokiniana strain P21. Maximal algal biomass production and total lipid yield were increased when strain BMI 10 was co-cultured (by 21 and 25 %, respectively). Furthermore, the nutrient removal efficiency of P21 was not significantly different under sterilized and unsterilized conditions. Harvestability of the strain was also increased under both conditions. Analysis of the amount and composition of fatty acids from this co-culture biomass revealed that it was quite satisfactory for biodiesel production (54.11–61.52% saturated fatty acids with a 0.59–0.82 degree of unsaturation). Overall, the results showed the co-culture of the alga and bacterium is a holistic enhancement that couples wastewater treatment with biodiesel production.

CHARACTERIZATION OF ZINC TOLERANT BACTERIAL STRAINS FROM THE ELECTROPLATING EFFLUENT CONTAMINATED SOIL

Toxic heavy metal pollution is expanding throughout the world as a result of industrial progress. This work focuses on the characterization of zinc tolerant bacterial strains from an electroplating effluent polluted soil sample in order to minimize/control metal pollution. pH, Temperature, Electrical Conductivity, Total Solids, Total Dissolved Solids, Total Suspended Solids, Chloride, Sodium, Calcium, Potassium, Biological Oxygen Demand, and Chemical Oxygen Demand were all measured and evaluated in the zinc-containing electroplating effluent sample. The sixteen bacterial strains were isolated from a polluted soil sample with electroplating effluent and identified using morphological and biochemical features. Using nutritional agar medium enriched with zinc metal, all of the chosen strains were evaluated for metal tolerance. Only six bacterial strains were chosen as potential metal tolerant strains based on the screening study, and these strains were characterized under various environmental conditions such as different pH (pH 5, pH 7, and pH 9), different temperatures (5°C, 28°C, 37°C, and 45°C), and different metal concentrations (100ppm, 200ppm, 300ppm and 400ppm). Pseudomonas sp strain 1 was shown to be a better zinc resistant organism, according to the findings

Isolation, characterization and S2−-oxidation metabolic pathway of a sulfur-oxidizing strain from a black-odor river in Beijing

Abstract A single strain capable of efficient S2−-oxidizing was isolated from a black-odor river in Beijing. The single strain was identified as Stenotrophomonas through the physiology and biochemical characteristics as well as the 16S rRNA sequencing experiment. This strain was named as Stenotrophomonas sp.sp3 (strain sp3). The experimental results showed that for the strain sp3 growth and S2− oxidization, the optimal conditions were as follows: 25 °C of temperature, initial pH 7, 2.5 g/L of initial glucose concentration and 1.00 g/L of initial cell concentration. It was found that there were 31 kinds of sulfur oxidation-related genes in the strain sp3 through the whole genomic analysis. The results of the transcriptome analysis suggested that the main metabolic pathway of S2− to SO42− was the paracoccus sulfur oxidation process. The bioconversion processes of S2− to S0, S2− to SO32−, S2O32− to S0 and SO32−, and SO32− to SO42− were controlled by hdrA, cysIJ, tst and sox gene, respectively.

Isolation and Characterization of Bacillus velezensis Strain P2-1 for Biocontrol of Apple Postharvest Decay Caused by Botryosphaeria dothidea.

Botryosphaeria dothidea causes apple ring rot, which is among the most prevalent postharvest diseases of apples and causes significant economic loss during storage. In this study, we investigated the biocontrol activity and possible mechanism of Bacillus velezensis strain P2-1 isolated from apple branches against B. dothidea in postharvest apple fruit. The results showed strain P2-1, one of the 80 different endophytic bacterial strains from apple branches, exhibited strong inhibitory effects against B. dothidea growth and resulted in hyphal deformity. B. velezensis P2-1 treatment significantly reduced the ring rot caused by B. dothidea. Additionally, the supernatant of strain P2-1 exhibited antifungal activity against B. dothidea. Re-isolation assay indicated the capability of strain P2-1 to colonize and survive in apple fruit. PCR and qRT-PCR assays revealed that strain P2-1 harbored the gene clusters required for biosynthesis of antifungal lipopeptides and polyketides. Strain P2-1 treatment significantly enhanced the expression levels of pathogenesis-related genes (MdPR1 and MdPR5) but did not significantly affect apple fruit qualities (measured in fruit firmness, titratable acid, ascorbic acid, and soluble sugar). Thus, our results suggest that B. velezensis strain P2-1 is a biocontrol agent against B. dothidea-induced apple postharvest decay. It acts partially by inhibiting mycelial growth of B. dothidea, secreting antifungal substances, and inducing apple defense responses.

The occurrence of rhizobacteria from Paspalum genotypes and their effects on plant growth

This work aimed to isolate and characterize plant growth promoting rhizobacteria (PGPR) from 10 Paspalum genotypes and evaluate the effect of their inoculation on P. regnellii, P. atratum, and P. malacophyllum genotypes. The bacterial population ranged from undetectable to 107 bacterial cells per gram of fresh matter in the Paspalum genotypes. Initially, we isolated 164 bacteria from rhizospheric soil and roots of the Paspalum genotypes using media N-free LG agar plate, semi-solid NFb, and LGI. The isolates were characterized genetically and physiologically. The sequencing of 16S rRNA showed the presence of many genera, and some are new in association with Paspalum. The most common was Bacillus followed by Rhizobium, Paraburkholderia, Enterobacter, Cupriavidus, Pseudomonas, Dyadobacter and Acinetobacter. Thirty-eight per cent of isolates produced siderophores, 25 % produced solubilized phosphate, and only 9 % produced indolic compounds. Three greenhouse experiments were performed in randomized blocks with six replicates using representative bacterial strains isolated from P. regnellii, P. malacophyllum and P. atratum cv. Pojuca. We also included strain Sp245 (Azospirillum baldaniorum), uninoculated control, and nitrogen control (150 kg N ha−1). There was an increase of up to 53 % in shoot dry matter in P. regnellii inoculated with strain Sp245 and the shoots accumulated more N. In contrast, only small effects were observed for the other Paspalum genotypes inoculated with PGPR from the host genotypes. This study shows a high diversity of diazotrophic rhizosphere bacteria and suggests no strain specificity between the bacterial isolates and the Paspalum genotypes.

Dose-Dependent and Time-Dependent Antitumor Activity of <i>Pleurotus ostreatus</i> Polysaccharides in Vitro

Elucidation of the<i> in vitro</i> antitumor effects of <i>Pleurotus ostreatus</i> polysaccharides is very important for their future clinical application. In this paper, we use Sarcoma-180 (S180) cells to test the antitumor activity of the mushroom polysaccharides. The S180 cells in freshly prepared mouse ascites were directly treated by water-soluble polysaccharides from mycelium of <i>Pleurotus ostreatus</i> and immediately detected by MTT [3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di- phenytetrazoliumromide] method. The results can be directly visualized with naked eyes through the color changes. The<i> in vitro</i> antitumor activity of <i>P. ostreatus</i> polysaccharides on S180 cells are dose-dependently and time-dependently. <i>P. ostreatus</i> strains p11, p23, P44, p105 and p176 showed significant inhibition to S180 cell activity under high polysaccharides concentration (1000μg/ml ~ 1250μg/ml), and there are non-significant effects under the middle concentration (750μg/ml). On the contrary, the S180 cell activity were significantly enhanced under low concentration (250μg/mL-500μg/ml). The effects of polysaccharides generally increased during 4-8 treat hours, but remained stable more than 7 hours. However, the strains P23, P44 and P105 enhanced the S180 cell activity for short time processing (4-5h), but inhibited the cell activity for long time processing (6-8h). Among the tested mushroom strains, P44 exhibited the highest inhibition rate (68.4%) under high concentration of 1250µg/ml and treat time of 7-8 hours, P23 had the highest enhancement (119.5%) under low concentration of 250µg/ml and treat time of 8 hours. The antitumor activity of <i>P. ostreatus</i> polysaccharides was dependent on its concentration and treat time, indicating the complicated antitumor mechanism of mushroom polysaccharides and the strict study should be conducted before their clinical application.

Safety of oil from Schizochytrium sp. (strain ATCC 20889) for use in infant and follow-on formula as a novel food pursuant to Regulation (EU) 2015/2283.

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on the safety of Schizochytrium sp. oil as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The NF which is the subject of the application is an oil rich in docosahexaenoic acid (DHA) that is produced by the microalgae Schizochytrium sp. (strain ATCC‐20889). The applicant proposed to add the NF in infant formulae (IF) and follow‐on formulae (FOF) at use levels in accordance with Regulation (EU) No 609/2013. The evidence provided by the applicant does not demonstrate to which species the strain Schizochytrium sp. ATCC 20889 belongs. As the source organism of the NF is not characterised at species level, no assessment for inclusion in the Qualified Presumption of Safety (QPS) list can be performed by EFSA. Marine biotoxins (including cyanotoxins) in the NF were below their limits of quantification. However, since it is unknown to which species the strain Schizochytrium sp. ATCC 20889 belongs, the concern that this strain has the potential to produce other toxins remains. No toxicological studies with the NF were provided by the applicant. Toxicological studies are available with DHA‐rich algal oils produced from other strains of Schizochytrium sp. However, the Panel considers that those toxicological studies cannot be used to establish the safety of the oil produced by the strain which is under assessment in this application (Schizochytrium sp. ATCC 20889). Therefore, based on the information provided by the applicant, the Panel concludes that the safety of the NF has not been established.

Effects of Azospirillum lectin on wheat seedling growth under salt stress

Azospirillum brasilense, which has the potential to stimulate plant growth, belongs to plant-growth-promoting bacteria. The positive effect of Azospirillum on plants may be due to different mechanisms. Azospirilla can assist in mitigation of many kinds of abiotic stress. Lectins are glycoproteins with different molecular masses and carbohydrate specificities. Azospirillum lectins are polyfunctional molecules. They promote plant growth and enzyme activity, they also can alter the plant cell content of stress metabolites, which attests that they can induce adaptation processes in wheat seedling roots. We investigated the dose-dependent effects of the lectin from A. brasilense strain Sp7 on the roots of 4-day-old wheat seedlings (Triticum aestivum L. cv. Saratovskaya 29) grown under salt stress. A low lectin concentration (0.3 mM L-1) improved seedling growth and alleviated the stress-induced growth inhibition. However, higher concentrations of lectin (1.2 mM L-1) did not affect the growth of the stressed seedling roots. In the roots of 4-day-old wheat seedlings under salt stress, the Sp7 lectin decreased total protein content and lipid peroxidation, which causes membrane damage, but increased the content of secondary metabolites such as total phenolics and total flavonoids. We conclude that the Azospirillum lectins are involved in adaptational changes in wheat seedling roots, due to which the relationship between bacteria and their hosts can be regulated under changing soil and climatic factors.

Effects of Temperature and pH on the Stability of Protease Produced by Alcaligenes faecalis P2

Background: Bacterial proteases represent a group of very important industrial enzymes. They are involved in the hydrolysis of peptide bond found in protein. Industrial application of bacterial proteases has been limited by low yield and instability at biotechnological process conditions. This study was design to investigate the effect of temperature and pH on the stability of protease produced by Alcaligene faecalis strain P2.&#x0D; Methodology: Protease-producing bacteria were isolated from beans effluent-impacted soil and screened for protease production on Casein agar plate. Protease assay was carried out following standard method for protease determination and the stability of the protease produced was investigated over temperature range of 20 to 90 oC and pH range of 3 to 12. The protease-producing bacterium was identified using its molecular characteristics.&#x0D; Results: Protease assay result showed that the amount of tyrosine released by one unit of the crude enzyme was 0.176 µmol/mL resulting in 0.19 U/mL protease activity. Stability studies showed that the protease had wide spectrum of pH and temperature stability. The protease was most stable at pH 9 and temperature of 40 oC after 30 min. Maximum protease activity of 1.259 U/mL was recorded with pH 9 after 30 min. The protease-producing bacterium was classified as Alcaligene faecalis P2 based on phylogenetic analysis of its 16S gene analysis. The sequences have been submitted to GenBank under the accession number MZ477004.&#x0D; Conclusion: This study therefore has demonstrated that beans effluent-impacted soil harbours protease producing bacteria with high industrial potentials. In addition, the study revealed that the protease produced in this study can retain its activity over wide temperature and pH.

Influence of Microbial Priming on Germination and Seedling Growth Traits of Compact Cotton CO17

Cotton, known as “the King of fibers”, is the predominant fiber in the Indian textile industry. Plant growth-promoting rhizobacteria (PGPR) represent a potential sustainable alternative for the enhancement and protection of crops. The germination and seedling growth of cotton can be optimized by inoculating with PGPR. An experiment was conducted to evaluate the effect of different PGPR strains on seed germination and seedling establishment characters on cotton. The highest germination percentage, maximum vigour index and leaf area was obtained with the PPFM TNAU1 strain inoculation. The maximum shoot and root length were observed with seeds treated with Azospirillum strain sp7 with an increase of 24.4 and 42.8% over the control. Underground fresh and dry matter was higher in seedlings treated with Azospirillum sp7 strain compared to control, while the PPFM TNAU1 strain treatment increased the aerial fresh and dry matter content because of its larger leaf area. Seeds inoculated with individual strain of Azospirillum sp7 and PPFM TNAU1 outperformed the combined inoculation of PGPR strains. The increase in germination traits and seedling characters by PGPR strains indicates the positive influence on improving cotton seedling establishment traits associated to higher yield.

Biocontrol of fungal plant diseases by Trichoderma sp strains. as an alternative for sustainable production. Some trials with good results in Argentina.

Biocontrol of fungal plant diseases by Trichoderma sp strains. as an alternative for sustainable production. Some trials with good results in Argentina.

Growth Promotion of Giant Duckweed Spirodela polyrhiza (Lemnaceae) by Ensifer sp. SP4 Through Enhancement of Nitrogen Metabolism and Photosynthesis.

Duckweeds (Lemnaceae) are representative producers in fresh aquatic ecosystems and also yield sustainable biomass for animal feeds, human foods, and biofuels, and contribute toward effective wastewater treatment; thus, enhancing duckweed productivity is a critical challenge. Plant-growth-promoting bacteria (PGPB) can improve the productivity of terrestrial plants; however, duckweed-PGPB interactions remain unclear and no previous study has investigated the molecular mechanisms underlying duckweed-PGPB interaction. Herein, a PGPB, Ensifer sp. strain SP4, was newly isolated from giant duckweed (Spirodela polyrhiza), and the interactions between S. polyrhiza and SP4 were investigated through physiological, biochemical, and metabolomic analyses. In S. polyrhiza and SP4 coculture, SP4 increased the nitrogen (N), chlorophyll, and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) contents and the photosynthesis rate of S. polyrhiza by 2.5-, 2.5-, 2.7-, and 2.4-fold, respectively. Elevated photosynthesis increased the relative growth rate and biomass productivity of S. polyrhiza by 1.5- and 2.7-fold, respectively. Strain SP4 significantly altered the metabolomic profile of S. polyrhiza, especially its amino acid profile. N stable isotope analysis revealed that organic N compounds were transferred from SP4 to S. polyrhiza. These N compounds, particularly glutamic acid, possibly triggered the increase in photosynthetic and growth activities. Accordingly, we propose a new model for the molecular mechanism underlying S. polyrhiza growth promotion by its associated bacteria Ensifer sp. SP4, which occurs through enhanced N compound metabolism and photosynthesis. Our findings show that Ensifer sp. SP4 is a promising PGPB for increasing biomass yield, wastewater purification activity, and CO2 capture of S. polyrhiza.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.