Bacillus Firmus Research Articles

Identification of Multi-Potent Protein Subtilisin A from halophilic bacterium Bacillus firmus VE2

Screening of halophiles with antimicrobial activity in saltpan soil samples from Nagapattinam district, Tamil Nadu, revealed isolate VE-2 as the most potent, identified as Bacillus firmus strain VE-2 through 16s rRNA gene sequencing. It had an optimum growth condition (OD 3.1) and antimicrobial protein (AMP) production (450 μg/mL) at 37 °C, pH 8, 25% NaCl, and 36 h incubation. SDS-PAGE analysis of the purified AMP showed the molecular weight of 36 kDa. HPLC analysis of the purified AMP showed different amino acids, such as asparagines, alanine, lysine, proline, threonine, glycine, cysteine, serine, aspartic acid leucine, and valine. Further characterization and identification using FT-IR, 2D-PAGE, MALDI-TOF, and in-silico analysis showed that the isolated AMP had the highest similarity to Subtilisin-A. It showed antibacterial activity against clinical bacterial pathogens like S. aureus, S. pyogenes, C. diphtheria, E. coli, and P. aeruginosa with the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration of 2.5 μg/mL and 20 μg/mL and also against various fungal pathogens such as A. niger, A. flavus, C. albicans, C. tropicalis and C. parapsilosis with the MIC and minimum fungicidal concentrations of 1.25–80 μg/mL. The purified AMP had excellent antioxidant potential, showed a scavenging effect against DPPH and Nitric oxide radicals, and displayed anticancer activity against HeLa cell lines with the IC50 values 53 μg/mL. Hence, the purified bioactive antimicrobial peptides (AMP) could also be used in anticancer therapies.

Efficient biological pretreatment and bioconversion of corn cob by the sequential application of a Bacillus firmus K-1 cellulase-free xylanolytic enzyme and commercial cellulases.

We used agricultural residue, corn cob, with biorefinery and bioeconomy concepts. At short-time cultivation in corn cob (12 h), Bacillus firmus K-1 produced cellulase-free xylanolytic enzyme, with xylooligosaccharides (XOSs), X5 and X6, as the main products, which can be used in a variety of applications. The xylanolytic enzyme produced from B. firmus K-1 effectively degraded xylan in corn cob, which was examined by chemical composition, scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR). After cultivation, the xylan contained in the corn cob residue was decreased (as biological pretreatment), causing morphological and structural changes, including creating porosity and increasing the surface area and the exposure of cellulose of pretreated corn cob. These results lead to an improvement of cellulose access by cellulases. Commercially available cellulases, Accellerase® 1500 and Cellic® CTec2, yielded significantly higher glucose concentrations from pretreated corn cob compared to untreated corn cob. After saccharification, the lignin-rich corn cob residue can be used as a raw material for other purposes. Moreover, the B. firmus cells, with a low risk to human health, can be used in some applications. This study presents an efficient method for producing high-value-added products from agricultural residue (corn cob) through biological processes which are environmentally friendly and economically viable. KEY POINTS: • High-value-added products were efficiently produced from corn cob byB. firmusK-1. • After biological pretreatment byB. firmusK-1, cellulase can better reach cellulose. • XOSs and cellulose-derived glucose were the main products from corn cob.

Alleviation of Salinity Stress in Peanut by Application of Endophytic Bacteria.

The development of salinity affects 7% of the world’s land surface, acting as a major constraint to crop productivity. This study attempted to use the co-evolving endophytes of peanut to alleviate salinity stress and enhance the yield of peanut. Diverse and different tissue colonizing endophytes were isolated from peanut and screened in vitro by seed germination bioassay imposing gradients of salinity, with two cultivars TG37A (susceptible) and GG2 (moderately resistant), in potted conditions using saline irrigation water. Finally, nine endophytes capable of producing IAA and ACC-deaminase, promoting root growth and yield in potted conditions were selected for further evaluation in field conditions. They were evaluated with saline water (1.5–2.0 dS/m) in saline soil with susceptible cultivar TG37A. Simultaneously, three endophytes (Bacillus firmus J22N; Bacillus tequilensis SEN15N; and Bacillus sp. REN51N) were evaluated with two cultivars, GG2 and TG37A, during rainy and post-rainy seasons with elevated salinity. The application of endophytes like Bacillus firmus J22N and Bacillus sp. REN51N enhanced the pod and haulm yield of peanuts by 14–19% across cultivars, salinity, and seasons. In addition, there was significant modulation in parameters like relative water content; production of enzymes like superoxide dismutase (SOD), glutathione reductase (GR), catalase (CAT), ascorbate peroxidase (APX), lipid peroxidase (POD), and H2O2 content in leaf; and uptake of potassium. The activities of the enzymes involved in scavenging reactive oxygen species (ROS) increased with salinity, and further increased with endophytes like Bacillus firmus J22N, Bacillus tequilensis SEN15N, and Bacillus sp. REN51N. There was an enhanced accumulation of proline, reduced level of phenol and H2O2, and enhanced uptake of potassium with the inoculation of endophytes. This improved scavenging capacity of plants by endophytic modulation of ROS scavengers, uptake of K, production of ACC deaminase and IAA, root and biomass growth, modulation in relative water content, and enhanced accumulation of osmoprotectant might be the reasons of alleviation of salinity stress. Endophytes could have alleviated salinity stress in peanuts, indicating the mechanisms and potential of peanuts at the field level. These endophytes could be applied to bring agricultural sustainability to salinity-affected areas in the future. Furthermore, few genera viz. Kocuria, Brevundimonas, Agrococcus, Dietzia, and Kytococcus were observed in peanut tissue for the first time.

Performance of Phosphate Solubilizing Bacteria in Tea (Camellia sinensis L.) Rhizosphere

A pot experiment was conducted to assess the effect of phosphate solubilizing bacteria (PSB) on the availability of applied P in acid soil using tea (Camellia sinensis L. var. CP-1) as test crop. Six strains of PSB (Bacillus firmus strain TPB-1, Burkholderia sp. strain TPB-33, Bacillus firmus strain TPB-38, Burkholderia sp. strain TPB-40, Burkholderia cepacia strain TPB-52 and Burkholderia sp. strain TPB-57) were used for inoculation using liquid and charcoal-based delivery system. To assess the effect of PSBs on P solubilization, bacterial inocula were used with and without rock phosphate (RP) application. Results indicated that maximum P-uptake (15.6 mg/pot) in tea shoot was recorded in case of inoculation with Burkholderia sp. strain TPB-57 using charcoal-based delivery system (T12-TPB 57C). As far as the crop response is concerned, the highest biomass yield of test crop (10.5 g/pot) was also recorded with T12-TPB 57C in the presence of RP. The study indicates that as far as P solubilization by PSB in tea rhizosphere is concerned, Burkholderia sp. strain TPB-57 is an efficient microbial genus.

Isolation and Characterization of Phosphate Solubilizing Microbes from Rock Phosphate Mines and Their Potential Effect for Sustainable Agriculture

Continuous application of phosphate (P) mineral to soil renders apatite addition during each crop growing season which is of great concern from a sustainable agriculture viewpoint. Use of efficient phosphate solubilizing microbes (PSB) is one of the most effective ways to solubilize this apatite mineral in the soil. The current study targeted hydroxyapatite mines to explore, isolate and characterize efficient P solubilizers to solubilize apatite in the soil. Efficiency of isolated microbes to solubilize rock phosphate (hydroxyapatite) and tri-calcium phosphate (TCP) as well as indole-3-acetic acid (IAA) and 1-aminocyclopropane-1-carboxylate deaminase (ACC) activity were tested. Identification and phylogenetic analysis of bacterial and fungal isolates were carried out by 16S rRNA and internal transcribed spacer (ITS) rDNA sequence analyses, respectively. The isolated bacterial strains were identified as Staphylococcus sp., Bacillus firmus, Bacillus safensis, and Bacillus licheniformis whereas fungal isolates were identified as Penicillium sp. and Penicillium oxalicum. Results showed that the impact of identified strains in combination with three phosphate fertilizers sources (compost, rock phosphate and diammonium phosphate (DAP)) was conspicuous on maize crop grown in pot. Both bacterial and fungal strains increased the P uptake by plants as well as recorded with higher available P in post-harvested soil. Penicillium sp. in combination with compost resulted in maximum P-uptake by plants and post-harvest soil P contents, compared to other combinations of P sources and bio-inoculants. Screening and application of efficient P solubilizers can be a better option to utilize the indigenous phosphate reserves of soil as well as organic amendments for sustainable agriculture.

Interaction between type of plant growth promoting rhizobacteria and patchouli varieties on growth and yield of patchouli (Pogostemon cablin Benth.)

A group of bacteria living in the rhizosphere area and capable to actively colonize the plant's root system called Plant Growth Promoting Rhizobacteria (PGPR). These bacteria can improve plant growth and yield. We determine the interaction between types of PGPR and patchouli varieties on growth and yield. This research was conducted at the Laboratory of Seed Science and Technology and Experimental Farm, Faculty of Agriculture, Syiah Kuala University, between January to June 2020. The collecting data from experiment were analyzed by factorial randomized block design with three replications. Seven type of rhizobacteria consist used without rhizobacteria, Necercia sp., Pseudomonas capacia, Bacillus firmus, Bacillus bodius, Bacillus alvei, Bacillus stearothermophillus. The varieties consist of three levels Tapak Tuan, Lhokseumawe, and Sidikalang. There was very significant interaction between rhizobacteria and varieties on the parameters of fresh weight and dry weight and significant interactions on plant height at 60 and 120 DAP, number of branches at 90 and 120 DAP, and leaf area. Variety of Sidikalang combination with P. capacia have very high wet weight (73.43 g), dry weight (18.05 g), and leaf area (84.00 cm2).

Assessing the efficacy of climate resilient microbial inoculants for enhanced phytochemical production from Indian licorice (Abrus precatorius L.)

Chemical fertilizers adversely affect beneficial micro-organism of the soil with high residual contamination in the plants which subsequently raises questions on the quality of useful metabolites of medicinal plants. The study investigates the efficacy of plant growth-promoting microbes, i.e., Bacillus pseudomycoides RS6B, Bacillus firmus RS7B, Aspergillus luchuensis RS6F, and Aspergillus tamarii RS8F, individually as well as in consortium on growth and glycyrrhizic acid content of Indian licorice (Abrus precatorius L). The maximum increase in biomass of root, stem, and leaves was obtained as 2.48 folds, 2.40 folds, and 2.41 folds along with 4.95, 4.63 and 2.61 folds in glycyrrhizic acid content, respectively on the rhizo-engineering of the consortium of all the 4 microbes. The microbial inoculants also increased soil organic carbon (1.44 times), available phosphorus (3.06 times), and microbial biomass carbon (3.01 times) in the soil after 120 DAS over non inoculated control. It appears that the microbial consortium of these 4 PGPMs is a highly efficient growth promoter over no microbes and individual PGPM for Indian licorice. It can be developed as a potential bioinoculant for the ecological cultivation of this important and commercial medicinal plant.

Screening of anti-Candida albicans metabolites produced by marine sponge-associated bacteria

This study selected bacteria with high anti-Candida albicans (CA) activity among ten bacteria isolated from marine sponges. Bacteria were cultivated using the basal medium to produce the extract. Minimum Inhibitory Concentration (MIC) microdilution broth was used as an anti-CA assay followed by TLC-direct bioautography to characterize their active compound with spray reagents. The bacteria determination was done by molecular approaches using Repetitive-Element Sequences-based-PCR (rep-PCR) and amplification of 16S rDNA partial gene sequences, continued with BLAST analysis. The four out of ten tested bacteria had high anti-CA compounds and were potentially to be produced on a larger scale using the basal medium, which was BYT5C4, BYT5C5, BYT1A, and BYT7, with MIC of 1 mg/mL against 7.5×106 CFU/mL CA. TLC-bioautography test results showed that all metabolites from each isolate had different Rf and types of metabolites. Rep-PCR test showed that four bacteria had a low similarity index, indicating that they were different species. Based on molecular identification results, the BYT5C4, BYT5C5, BYT1A, and BYT7 isolates are strictly related to Brevibacterium casei, Exiguobacterium profundum, Micrococcus lylae, and Bacillus firmus, respectively. The active metabolites identified in this study can be isolated to determine the active molecules and their inhibitory routes to fungal growth. It is worth noting that additional research might be conducted to compare the activity of each antifungal metabolite to the synergistic activity of numerous antifungal metabolites detected in plant extracts.

Hydrogen production by sequential dark and photofermentation using wet biomass hydrolysate of Spirulina platensis: Response surface methodological approach

Microalgae and cyanobacteria can be used as a potential biomass to produce hydrogen from stored glycogen and starch through fermentation and photofermentation. In this study, the potential of algal biomass i.e. Spirulina platensis hydrolysate as a substrate for sequential fermentative (I-stage) and photo-fermentative (II-stage) biohydrogen production was evaluated. Response Surface Methodology (RSM) was employed to find the optimum photofermentation conditions. From the preliminary optimization experiments, it was found that the significantly affecting factors for H2 production were pH, dilution fold (D.F.) of fermentate and Fe(II) sulfate concentration during photofermentation (second stage). In the present study, 1% (w/v) Spirulina platensis hydrolyzate produced 23.06 ± 3.63 mmol of H2 with yield of 1.92 ± 0.20 mmol H2/g COD reduced. In the second stage experiment 1510 ± 35 mL/l hydrogen was produced using inoculum volume-20.0% (v/v) and inoculum age-48 h of co-culture of Rhodobacter sphaeroides NMBL-01 and Bacillus firmus NMBL-03 under conditions pH-5.95, D.F. of dark fermentate-20.30 folds, Fe(II) sulfate concentration-0.412 μM, temperature-32±2 °C and light intensity-2.5 klux.

Assessing the Risk of Transfer of Microorganisms at the International Space Station Due to Cargo Delivery by Commercial Resupply Vehicles.

BackgroundWith increasing numbers of interplanetary missions, there is a need to establish robust protocols to ensure the protection of extraterrestrial planets being visited from contamination by terrestrial life forms. The current study is the first report comparing the commercial resupply vehicle (CRV) microbiome with the International Space Station (ISS) microbiome to understand the risks of contamination, thus serving as a model system for future planetary missions.ResultsSamples obtained from the internal surfaces and ground support equipment of three CRV missions were subjected to various molecular techniques for microbial diversity analysis. In total, 25 samples were collected with eight defined locations from each CRV mission prior to launch. In general, the internal surfaces of vehicles were clean, with an order of magnitude fewer microbes compared to ground support equipment. The first CRV mission had a larger microbial population than subsequent CRV missions, which were clean as compared to the initial CRV locations sampled. Cultivation assays showed the presence of Actinobacteria, Proteobacteria, Firmicutes, and Bacteroidetes and members of Ascomycota and Basidiomycota. As expected, shotgun metagenome analyses revealed the presence of more microbial taxa compared to cultivation-based assays. The internal locations of the CRV microbiome reportedly showed the presence of microorganisms capable of tolerating ultraviolet radiation (e.g., Bacillus firmus) and clustered separately from the ISS microbiome.ConclusionsThe metagenome sequence comparison of the CRV microbiome with the ISS microbiome revealed significant differences showing that CRV microbiomes were a negligible part of the ISS environmental microbiome. These findings suggest that the maintenance protocols in cleaning CRV surfaces are highly effective in controlling the contaminating microbial population during cargo transfer to the ISS via the CRV route.

Effects of the outer-cleft aromatic ring deletion on the resistivity of a GH11 xylanase to the lignin-like monolignol aggregates

The effects of outer-cleft aromatic ring mutations Y5A and F124A on the resistivity of a GH11 xylanase (xyn11A) from Bacillus Firmus K1 to the inhibition by highly-concentrated coniferyl alcohols were investigated both in vitro and an in silico, in which coniferyl alcohols tended to aggregate into clusters and induced the inhibition. The mutants displayed a lower inhibition percentage despite the decrease in enzymatic activities due to the mutation-induced conformational changes of xyn11A. The mutants' ability to resist coniferyl alcohols could be explained by the disruption of the coniferyl clusters formed within the binding cleft due to aromatic ring deletions.

<p>Production of xylanase under submerged fermentation from <em>Bacillus firmus</em> HS11 isolated from Sikkim Himalayan region</p>

Xylanase producing microorganisms isolated from high altitude soil show activity at broad window of temperature, and can have variety of industrial applications. Here, we explored production of xylanase under submerged fermentation from Bacillus firmus HS11 isolated from Sikkim Himalayan region. We isolated 472 bacterial strains high altitude soil samples (1120-4272 m) from Sikkim and screened for xylanase production. Among them five strains that showed higher xylanase activity were identified by 16s rRNA gene sequence analysis. comparatively, Bacillus firmus HS11 showed highest activity at 10, 37 and 50°C, and was chosen for optimization experiment. B. firmus HS11 showed xylanase activity of 3.35 U/mg of protein at 37°C and retained 32.43% activity at 10°C and had 79.82% higher activity at 50°C. Optimization of nutrient composition for submerged fermentation of B. firmus HS11 was carried out by combination of Plackett-Burman design and response surface methodology. The optimized media component for xylanase production by submerged fermentation by B. firmus HS11 is beechwood xylan 0.8% (w/v), MgSO4 0.04% (w/v), CaCl20.04% (w/v), peptone 0.1% (w/v), NaCl 0.3% (w/v) and yeast extracts 0.01% (w/v), resulting in enhancement of xylanase production by 7.4 folds. Xylanase having activity at broad range of temperature including lower temperature can have application in food industry.

Evaluación del efecto de Bacillus firmus C101 en el crecimiento de poslarvas de Litopenaeus vannamei Boone (camarón blanco) y Brachionus plicatilis s.s. Müller (rotífero)

La creciente demanda de proteína acuícola sugiere buscar alternativas biotecnológicas que mejoren el cultivo de especies de interés comercial. En este estudio se evaluó Bacillus firmus C101 como promotor del crecimiento y potencial probiótico, el cual fue caracterizado y posteriormente administrado (106 UFC mL-1 * día) en poslarvas de camarón blanco (Litopenaeus vannamei) y en rotíferos (Brachionus plicatilis sensu stricto). Se observó que B. firmus C101 tiene tolerancia a sales biliares, fuerte actividad fosfatasa y actividad antimicrobiana frente a patógenos como Vibrio alginolyticus y Aeromonas hydrophila, entre otros. Por otro lado, tras su administración por tres semanas a poslarvas de camarón causó un aumento significativo (p < 0,05) en la tasa específica de crecimiento (TEC = 3,8 ± 0,7 % día-1), el incremento de peso diario (ADG = 1,5 ± 0,1 mg día-1) y en la tasa de conversión alimenticia (TCA = 1,5 ± 0,1 %) en comparación con los controles sin adición de esta bacteria (PBS estéril). Así mismo, la administración de B. firmus C101 (106 UFC mL-1 * día) a rotíferos causó un aumento en la tasa de crecimiento poblacional (TC = 20,2 ± 1,5 % día-1), fecundidad (F = 0,4 ± 0,03 huevos individuos-1) y productividad (R = 16,0 ± 0,7 individuos mL-1 * día), después de 48 h de cultivo. Con base en lo anterior y en comparación con otros estudios, se sugiere a B. firmus C101 como potencial probiótico y promotor del crecimiento en poslarvas de camarón, y como primer reporte del efecto de su administración en rotíferos. No obstante, se precisan estudios sobre los posibles mecanismos de acción, y pruebas a escala piloto y comercial para validar estos resultados y su posible transferencia al sector productivo.

Bacillus firmus Strain I-1582, a Nematode Antagonist by Itself and Through the Plant.

Bacillus firmus I-1582 is approved in Europe for the management of Meloidogyne on vegetable crops. However, little information about its modes of action and temperature requirements is available, despite the effect of these parameters in its efficacy. The cardinal temperatures for bacterial growth and biofilm formation were determined. The bacteria was transformed with GFP to study its effect on nematode eggs and root colonization of tomato (Solanum lycopersicum) and cucumber (Cucumis sativus) by laser-scanning confocal microscopy. Induction of plant resistance was determined in split-root experiments and the dynamic regulation of genes related to jasmonic acid (JA) and salicylic acid (SA) by RT-qPCR at three different times after nematode inoculation. The bacteria was able to grow and form biofilms between 15 and 45°C; it degraded egg-shells and colonized eggs; it colonized tomato roots more extensively than cucumber roots; it induced systemic resistance in tomato, but not in cucumber; SA and JA related genes were primed at different times after nematode inoculation in tomato, but only the SA-related gene was up-regulated at 7 days after nematode inoculation in cucumber. In conclusion, B. firmus I-1582 is active at a wide range of temperatures; its optimal growth temperature is 35°C; it is able to degrade Meloidogyne eggs, and to colonize plant roots, inducing systemic resistance in a plant dependent species manner.

Biological pretreatment of rice straw with cellulase-free xylanolytic enzyme-producing Bacillus firmus K-1: Structural modification and biomass digestibility

Biological pretreatment using microorganisms or enzymes offers an eco-friendly process for biomass processing. Herein, the efficiency of pretreatment of rice straw with the cellulase-free xylanolytic enzyme-producing Bacillus firmus K-1 and its enzymes was assessed. After pretreatment with strain K-1 (BRS), the xylan content in rice straw reduced significantly (21% removal), thus increasing exposure of the cellulose crystal structure (Crystallinity index (CrI) = 40.2%) and creating biomass porosity. Subsequent treatment of BRS with the in-house xylanase preparation (BRS-E) slightly increased xylan removal (30% removal). The reduction of xylan thus led to larger pore size and increased crystallinity (CrI = 42.8%). Compared to untreated rice straw (24% glucan conversion), hydrolysis of BRS and BRS-E with the commercial cellulase preparation Accellerase 1500 at 100 g/L substrate load showed comparable glucose yield, giving about 74% glucan conversion. The results indicate that the removal of xylan can enhance accessibility of cellulose to cellulases, although the lignin content was not reduced (24% for BRS and 25% for BRS-E). This work demonstrates a new insight into the improvement of pretreatment efficiency using a xylan-degrading microorganism, which is an alternative to conventional lignin removal by fungal pretreatment.

ISOLASI MIKROBA PENGHASIL ANTIBIOTIK DARI PASIR PANTAI LEMO-LEMO KABUPATEN BULUKUMBA DALAM MENGHAMBAT BEBERAPA BAKTERI PATOGEN

Research on the isolation of antibiotic-producing microbes from the sand of Lemo-lemo beach in Bulukumba Regency has been carried out in inhibiting several pathogenic bacteria. This study aims to obtain microbes from beach sand that can produce antibiotics. The first stage of microbial isolation was carried out by diluting 10-1 to 10-7 using the pour method on Glucose Nutrient Agar (GNA) and Potato Dextrosa Agar (PDA) medium, then fermented using Maltose Yeast Broth (MYB) medium. The activity was tested using agar diffusion in Nutrient Agar (NA) medium against the test microbes. The results obtained 7 bacterial isolates and 3 fungal isolates showing the clear zone around them. The bacterial isolate that provides the best activity is AB6 isolate which can inhibit many pathogenic microbes, namely Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Salmonella thypi, Staphylococcus aureus, Sthapylococcus epidermis and Vibrio colera. Meanwhile, all fungal isolates provided good activity against the tested microbes, namely isolates AJ1, AJ2, and AJ3. The next step was macroscopic morphological observations by looking at bacterial growth on the medium NA upright, NA slanted, NB while microscopically Gram staining was carried out, where isolates AB1 to AB7 is a gram-positive bacillus. Furthermore, the biochemical activity test was carried out which included motility test, catalase test, citrate test, and temperature variation growth test. Based on the results of the study, it was found that AB1 to AB7 isolates belonged to the genus Bacillus and had Bacillus firmus species identified using the vitek2 compact tool. Meanwhile, the fungal isolates, namely AJ1 and AJ2, were included in the penicillium fungus and AJ3 included the Apergillus fungus.

Effects of ILeVO Seed Treatment on Heterodera glycines Reproduction and Soybean Yield in Small-Plot and Strip-Trial Experiments in Iowa.

ILeVO (fluopyram) is a fungicide seed treatment for soybean sudden death syndrome (SDS) that also has nematicidal activity. ILeVO is sold with a base of insecticide Poncho (clothianidin), nematode-protectant VOTiVO (Bacillus firmus), and Acceleron fungicides (metalaxyl, fluxapyroxad, and pyraclostrobin). Yield and reproduction of the soybean cyst nematode (SCN) (Heterodera glycines) on soybean plants grown from seed treated with ILeVO plus the base were compared with those treated with only the base in 27 small-plot experiments and 12 strip-trial experiments across Iowa from 2015 to 2017. To increase the likelihood that yield results were related to effects on SCN, data were used only from 26 small-plot experiments and 12 strip trials in which symptoms of SDS were low or nonexistent. An SCN reproductive factor (RF) was calculated for each experimental unit by dividing the SCN population density at harvest by the population density at planting. ILeVO significantly reduced SCN RF by 50% in one strip-trial experiment and by 36 to 60% in four small-plot experiments but yields were not increased by ILeVO in any of those five experiments. Soybean yields were 2.8 to 3.7 bushels/acre (bu/ac) (188.3 to 248.8 kg/ha) greater with ILeVO in three small-plot experiments but SCN RF was not reduced in those experiments. Also, yield was 1.9 bu/ac (127.8 kg/ha) greater with ILeVO in one strip-trial experiment in 2016 but SCN samples were not collected at harvest from the study to assess the possible effects of ILeVO on SCN reproduction. When strip-trial data from 2015 and 2016 were combined, there was a small but significant 0.8 bu/ac (52.2 kg/ha) yield increase with ILeVO. Overall, the effects of ILeVO on SCN reproduction and soybean yield were variable in these field studies.

A STUDY ON THE COLOR REMOVAL OF DIFFERENT FORON DYES BY USING THERMOFILIC AND MESOPHILIC BACILLUS SPECIES

There is a significant increase in industrial activities due to the increasing population and demand. Textile and dye industries are also important groups of these industrial fields. In these fields, high amounts of dyes are used. After dyeing process, 10-15% of dyes are discharged into wastewaters. Existence of dyes in wastewaters is an undesired condition because they cause lots of diseases on living beings and also various problems on aquatic and terrestrial environments. Because disperse dyes do not show ionization in aquatic environments, they generally tend to bioaccumulation. Conventional biological wastewater treatment systems are not efficient for color removal of dyes. In this study, bacterial decolorization, which is an environmentally friendly and effective method, was investigated. For this aim, a thermophilic (Bacillus firmus) and a mesophilic bacterium (Bacillus subtilis) were tested in the color removal of various Foron textile dyes, a group of disperse dyes, such as Foron Brown (FB), Foron Black (FBL), Foron Turquoise (FT), Foron Violet (FV) and Foron Red (FR). The tested dyes (200 mg/L) were incubated with Bacillus species under the shaking condition for 24 h at various temperatures. Colors of all the dyes were efficiently removed by both bacterial species at the end of 24 h of incubation. The highest color removal rates of FB, FBL, FT, FV and FR treated with B. firmus were about 63, 87, 56, 77 and 74%, respectively. The maximum decolorization percentages of the same dyes incubated with B. subtilis were determined as 69, 80, 55, 73 and 59%, respectively.

In-vitro efficacy of different antibiotics used in the treatment of bacteria isolated from bovine mastitis in South Khartoum

Mastitis is the most important disease in dairy farms worldwide causing significant economic losses. Sixty milk samples were collected from mastitic cows and submitted to the laboratory for further bacteriological examinations, Staphylococcus spp. (45%), Bacillus spp. (22.5%), Enterobacter spp. (14.5%), Pseudomonas spp. (8%), Acinobacter spp (5%) and Micrococcus spp (5%) were found in bacteriological examination of all milk samples. Staphylococcus aureus was the most prevalent among Staphylococci isolates (45%), followed by Staphylococcus intermedius (22%), Staphylococcus warneri (11%), Staphylococcus hyicus (11%), Staphylococcus chromogenes (11%) and Staphylococcus lentus (11%) Also Bacillus spp were found to be: Bacillus alvei (40%) Bacillus thermophilus (20%), Bacillus coagulans (20%) and Bacillus firmus (20%). Sensitivity tests were conducted using 12 different antibiotics including Tetracycline and Gentamicin. The sensitivity was determined for each antibiotic by using disc diffusion technique according to Kirby–Bauer method. The isolated bacteria were highly sensitive to Ciprofloxacin, Ifovluxtsen, Linezolid, Gentamicin and they were found to be resistant to Cloxacillin, Cephalexin, followed by Tetracycline, Lincomycin. Roxithromycin. This study showed that the most causative agent of mastitis in south Khartoum is Staphylococcus aureus. Hygienic practices procedure in dairy farm must be sustainable to reduce this disease and to be aware about the suitable antibiotics to be used using antibiotic sensitivity test. The present study was designed to investigate the sensitivity of different antibiotics against bacteria isolated from suspected mastitic cows in dairy farms in south Khartoum, Sudan. Keywords: Staph. aureus, Bacillus, Antibiotics, Mastitis, Ceprofloxacin, Sensitivity.

Reducing stress by improving performance of hatchery-reared Catarina scallop (Argopecten ventricosus) spat with different genera of beneficial microorganisms: A biochemical and molecular analysis

This study investigated the probiotic effects of one lactobacillus, one marine yeast, mix of three bacilli and mix of all probiotic strains on the growth, survival, antioxidant response (superoxide dismutase = SOD, catalase = CAT, gluthatione peroxidase = GPX) and immune response (lysozyme = LYZ, heat shock protein =HSP70) of hatchery-reared Catarina scallop Argopecten ventricosus early spat. The spat was exposed every three days for 28 days to a single dose of 1 × 106 CFU mL–1 of one of five treatments used in triplicate: (1) Lactobacillus plantarum (C3); (2) Candida cretensis (S10); (3) Mix of Bacillus cereus, Bacillus flexus, and Bacillus firmus (BMix); (4) Mix of 1 + 2+3 (LLBMix); (5) Group of spat without probiotics as control. Survival was 100 % in all probiotic treatments and the control group. The spat treated with the yeast (S10) and lactobacillus (C3) significantly increased absolute growth and growth rate compared to the control. The antioxidant activity and gene expression was significantly lower in all spat treated with probiotics than in the control group, particularly with the BMix, LLBMix (SOD), C3 (CAT, GPX), and BMix (CAT) strains. The immune activity and gene expression was also significantly lower in spat treated with probiotics, particularly BMix, LLBMix (LYZ), C3, BMix, and S10 (HSP70) strains, compared to the control group. The use of a single dose of probiotic or mix of different strains reduced activation of antioxidant and immune response and improved overall performance of hatchery-reared A. ventricosus spat.