S1 Isolates Research Articles

Characterization of Priestia megaterium S1, a polymer degrading gut microbe isolated from the gut of Tenebrio molitor larvae fed on Styrofoam.

This study reveals that Tenebrio molitor larvae are fed with two different feeds i.e., barley bran along with Styrofoam, and barley bran without Styrofoam, the survival percentage of mealworms shows 86 and 89%, respectively. Five isolates namely S1, S2, S3, S4, and S5 were isolated from the gut of Styrofoam-feeding Tenebrio molitor larvae and tested for Hydrophobicity percentage, clear zone assay and turbidity measurement. S1 isolate showed best (turbidity percentage of 19.65%, 13.54% hydrophobicity percentage, and 37% zone of clearance) when compared to other isolates, respectively. 16S rRNA characterization of S1 isolate revealed that the isolate belongs to Priestia megaterium S1(ON024787). Biodegradation of PE and PS beads by Priestia megaterium S1 makes physical and structural changes over 180days, after microbial adhesion to the beads. Growth parameters have shown that the Priestia megaterium S1 thrives more effectively in the pH (6.5), temperature (28°C) and at 1.5% LDPE/HDPE/PS concentration there is maximum utilization of carbon and a high percentage survival rate. Significant colonization of the isolate after 30 days over beads of LDPE (52.47%), HDPE (49.26%), and PS (48.11%), respectively. Experimental data revealed that Priestia megaterium S1 have PE and PS beads degradation capacity, proven by weight loss studies, at 6th-month percentage weight loss of LDPE (36.1%), HDPE (31.9%), and PS (28.6%), the percentage loss of carbon and hydrogen shows higher when compared to control. One month Biological Oxygen Demand (BOD) showed that LDPE (7.4mg/l), HDPE (7.2mg/l), PS (6.7mg/l), and simultaneous studies on CO2 evolution over LDPE treatment is 5.05g/l, HDPE (4.26g/l), and PS (3.91g/l), respectively. Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM) prove the occurrence of biodegradation on the surface of beads. This work highlights that Priestia megaterium S1 plays a vital role in effectively degrading PE and PS beads.

Molecular Characterization, Statistical analysis of protease and its application

Proteolytic enzymes are currently attracting enormous attention because of their biotechnological potential. Currently, bacterial proteases are in great demand because of potential industrial applications that are found in soil or mud. This research was conducted to find the proteolytic bacteria isolation from PKC (Palm Kernel Cake) sample collected from Oil Palm India Limited, Kollam, Kerala and it was screened for a novel protease producing bacteria in Skim milk agar medium. Among the isolates, the S1 isolate exhibited high proteolytic activity and was selected as a novel protease-producing bacteria, which was identified by morphological and biochemical characteristics as Pseudomonas aeruginosa. The optimization study was carried out for pH, carbon, substrate, surfactants, nitrogen, metal ions, and inoculum size for determining the maximum production of protease. The results are stated thereby.

ISOLATION AND IDENTIFICATION OF EGYPTIAN STRAINS OF Serratia marcescens PRODUCING ANTIBACTERIAL AND ANTIOXIDANT PRODIGIOSIN PIGMENT

Prodigiosin is a natural red pigment, it is an alkaloid secondary metabolite with a unique tripyrrole structure produced by Serratia marcescens, it’s motile, short-rod shaped, G- bacteria, classified in the large family of Enterobacteriaceae. 13 isolates were isolated from 32 soil samples, which showed clear red pigmented colonies. The Egyptian Serratia marcescens isolates were identified based on morphological, biochemical and then only the two best isolates for pigment production (M1, S1) were identified by MALDI-TOF mass spectrometry technique. The two selected species gave a score value between 2.565 to 2.668 (100%) were correctly identified by MALDI-TOF- MS to the genus and species levels. The average daily rate of pigment production by M1 and S1 isolates estimated by 421.6 and 326.1 unit/cell, respectively. Antibacterial activity of prodigiosin was determined by disc diffusion assay against 7 types of G- and 4 types of G+ pathogenic bacteria. Minimum inhibitory concentration (MIC) and the concentration inducing 50% inhibition of the bacterial growth (IC50)against the mentioned bacteria were determined and prodigiosin was proved to be effective in inhibiting bacterial growth. Prodigiosin possess antioxidant activity assayed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) reduction method and this activity increased gradually with increasing concentrations.

Molecular and biological characterization of a novel mild strain of citrus tristeza virus in California.

Strain differentiating marker profiles of citrus tristeza virus (CTV) isolates from California have shown the presence of multiple genotypes. To better define the genetic diversity involved, full-length genome sequences from four California CTV isolates were determined by small-interfering RNA sequencing. Phylogenetic analysis and nucleotide sequence comparisons differentiated these isolates into the genotypes VT (CA-VT-AT39), T30 (CA-T30-AT4), and a new strain called S1 (CA-S1-L and CA-S1-L65). S1 isolates had three common recombination events within portions of genes from VT, T36 and RB strains and were transmissible by Aphis gossypii. Virus indexing showed that CA-VT-AT39 could be classified as a severe strain, whereas CA-T30-AT4, CA-S1-L and CA-S1-L65 were mild. CA-VT-AT39, CA-S1-L, and CA-S1-L65 reacted with monoclonal antibody MCA13, whereas CA-T30-AT4 did not. RT-PCR and RT-qPCR detection assays for the S1 strain were developed and used to screen MCA13-reactive isolates in a CTV collection from central California collected from 1968 to 2011. Forty-two isolates were found to contain the S1 strain, alone or in combinations with other genotypes. BLAST and phylogenetic analysis of the S1 p25 gene region with other extant CTV sequences from the NCBI database suggested that putative S1-like isolates might occur elsewhere (e.g., China, South Korea, Turkey, Bosnia and Croatia). This information is important for CTV evolution, detection of specific strains, and cross-protection.

Isolation and identification of a cellulolytic Enterobacter from rumen of Aceh cattle.

Aims:The aim of this study was to isolate and identify a cellulolytic bacterium from the rumen fluid of Aceh’s cattle. Biodegradation by cellulolytic rumen bacteria can be used as a source of cellulolytic bacteria that act to degrade feed fibrous material so as to improve the quality of nutrients and digestibility of feed ingredients at a cheaper price than the use of commercial cellulase enzymes.Materials and Methods:Samples were collected from rumen fluid of Aceh’s cattle in Abattoirs (RPH) of Banda Aceh city, Indonesia, isolation, and screening of cellulolytic bacteria were done in Microbiology Laboratory, Faculty of Veterinary Medicine, Syiah Kuala University, Banda Aceh, Indonesia.Results:The S1 isolates showed ±2.5 cm of clear zone diameter. Microscopically, this strain was found to be a Gram-negative, Bacillus. Homology and phylogenetic tree analysis of 16S rRNA showed that S1 isolate has 91% of sequence similarity with that of Enterobacter cloacae. 91% sequence homology shown in this study proved that the S1 isolate is probably either a new species or another genus of Enterobacteriaceae.Conclusion:Current study suggests that cellulose hydrolytic bacteria isolated from rumen fluid of Aceh cattle on Bushnell Haas medium-carboxymethylcellulose agar, and some potent cellulose degrading bacteria have been identified.

Effects of Glucose and Starch on Lactate Production by Newly Isolated Streptococcus bovis S1 from Saanen Goats.

When ruminants are fed high-concentrate diets, Streptococcus bovis proliferates rapidly and produces lactate, potentially causing rumen acidosis. Understanding the regulatory mechanisms of the metabolism of this species might help in developing dietary strategies to alleviate rumen acidosis. S. bovis strain S1 was newly isolated from the ruminal fluid of Saanen dairy goats and then used to examine the effects of glucose and starch on bacterial metabolism and gene regulation of the organic acid-producing pathway in cultures at a pH of 6.5. Glucose or starch was added to the culture medium at 1 g/liter, 3 g/liter (close to a normal range in the rumen fluid), or 9 g/liter (excessive level). Lactate was the dominant acid produced during the fermentation, and levels increased with the amount of glucose or starch in a dose-dependent manner (P < 0.001). The production of formate and acetate in the fermentation media fluctuated slightly with the dose but accounted for small fractions of the total acids. The activities of lactate dehydrogenase (LDH) and α-amylase (α-AMY) increased with the starch dose (P < 0.05), but the α-AMY activity did not change with the glucose dose. The relative expression levels of the genes ldh, pfl (encoding pyruvate formate lyase), ccpA (encoding catabolite control protein A), and α-amy were higher at a dose of 9 g/liter than at 1 g/liter (P < 0.05). Expression levels of pfl and α-amy genes were higher at 3 g/liter than at 1 g/liter (P < 0.05). The fructose 1,6-diphosphate (FDP) concentration tended to increase with the glucose and starch concentrations. In addition, the S. bovis S1 isolate fermented glucose much faster than starch. We conclude that the quantities of glucose and soluble starch had a major effect on lactate production due to the transcriptional regulation of metabolic genes. This work used a newly isolated S. bovis strain S1 from the rumen fluid of Saanen goats and examined the effects of glucose and soluble starch on organic acid patterns, enzyme activity, and expression of genes for in vitro fermentation. It was found that lactate was the dominant product from S. bovis strain S1, and the quantities of both glucose and starch in the medium were highly correlated with lactate production and with the corresponding changes in associated enzymes and genes. Therefore, manipulating the metabolic pathway of S. bovis to alter the dietary level of readily fermentable sugar and carbohydrates may be a strategy to alleviate rumen acidosis.

MERCURY REDUCTASE ACTIVITY OF AN INDIGENOUS MERCURY RESISTANT BACTERIAL ISOLATE (Bacillus sp. S1) FROM KALIMAS-SURABAYA AS A POTENTIAL REDUCING AGENT FOR MERCURIAL ION (HG2+)

&lt;p&gt;Mercury reductase activity and Hg2+ lowering capacity of a Mercury Resistant Bacteria (MRB) (Bacillus sp. S1) which was isolated from Kalimas River of Surabaya, Indonesia were studied. The activity was determined by Mercury Reductase Assay System (MRAS) in a solution mixture contained 50 mM PBS (pH ± 7.0), 0.5 mM EDTA, 200 µM MgSO4, 0.1% (v/v) ß-merchaptoethanol, 200 µM NADH2 and 25 mg/L HgCl2 and one volume of crude extract incubated at room temperature for various interval period of time. Mercury reductase activity was measured spectrophotometrically at 340 nm. One unit of reductase activity was defined as one molar of oxidized NADH2 produced per total cell per minute. Results of study showed that, the isolate could resist the concentration of HgCl2 up to 11 mg/L. At 30 minute incubation period at room temperature, the highest mercury reductase activity and the Hg2+ lowering capacity was found to be 0.006 unit/109cell and &lt;br /&gt;1.48 mg/L/109cell/minute, respectively with the reduction efficiency of Hg2+ to Hg0 of 0.18% per minute. Therefore, it can be concluded that the Bacillus sp. S1 isolate could be assumed to be exellent mercury bioremediation agent since it was found to be highly mercury resistant and very efficient to reduce cationic mercury (Hg2+) to elemental mercury (Hg0). &lt;/p&gt;&lt;p&gt;&lt;strong&gt;Keywords&lt;/strong&gt;: Kalimas-Surabaya, Bacillus sp. S1, Mercury resistant, Mercury reductase&lt;/p&gt;

Cryptic species of Paracoccidioides brasiliensis: impact on paracoccidioidomycosis immunodiagnosis.

We aimed to evaluate whether the occurrence of cryptic species of Paracoccidioides brasiliensis, S1, PS2, PS3 and Paracoccidioides lutzii, has implications in the immunodiagnosis of paracoccidioidomycosis (PCM). Small quantities of the antigen gp43 were found in culture filtrates of P. lutzii strains and this molecule appeared to be more variable within P. lutzii because the synonymous-nonsynonymous mutation rate was lower, indicating an evolutionary process different from that of the remaining genotypes. The production of gp43 also varied between isolates belonging to the same species, indicating that speciation events are important, but not sufficient to fully explain the diversity in the production of this antigen. The culture filtrate antigen AgEpm83, which was obtained from a PS3 isolate, showed large quantities of gp43 and reactivity by immunodiffusion assays, similar to the standard antigen (AgB-339) from an S1 isolate. Furthermore, AgEpm83 was capable of serologically differentiating five serum samples from patients from the Botucatu and Jundiaí regions. These patients had confirmed PCM but, were non-reactive to the standard antigen, thus demonstrating an alternative for serological diagnosis in regions in which S1 and PS2 occur. We also emphasise that it is not advisable to use a single antigen preparation to diagnose PCM, a disease that is caused by highly diverse pathogens.

Plant growth promoting rhizobacteria as agents in the biocontrol of eucalyptus mini-cutting rot

The effectiveness of ten plant growth-promoting rhizobacteria (PGPR) was evaluated for the control of mini-cutting rot of eucalyptus caused by Cylindrocladium candelabrum and Rhizoctonia solani. Inhibition of the in vitro mycelial growth of each pathogen differed with PGPR isolate and culture medium evaluated. The most effective group of isolates was FL2 (Pseudomonas sp.), 3918, S1 and S2 (Bacillus subtilis). Under nursery conditions, isolate Ca (Pseudomonas fulva) reduced the incidence of mini-cutting rot caused by C. candelabrum by 33% compared to the control, and by 27% compared to a fungicide treatment (epoxiconazole + pyraclostrobin: 0.4 g.L-1). Inoculum density of C. candelabrum in the eucalyptus rooting medium decreased significantly beginning at 10 days after the medium was treated with the PGPR isolates. Isolate Ca was the most efficient in reducing the C. candelabrum inoculum at 15 days and in promoting rooting and growth of eucalyptus. For R. solani, no differences in disease incidence were found among treatments. Sensitivity of the PGPR isolates to ten fungicides differed widely. Tebuconazole completely inhibited 80% of the isolates, but epoxiconazole + pyraclostrobin only inhibited the S1 isolate. Isolate S1 was the most sensitive and isolates 3918 and MF2 the most resistant to the majority of active ingredients tested. Isolate Ca was selected for biological control studies in eucalyptus nursery conditions.

Distribution, Pathogenicity, and Interactions of Two Strains of Rice yellow mottle virus in Forested and Savanna Zones of West Africa.

In Côte d'Ivoire, the S2 strain of Rice yellow mottle virus (RYMV) predominated in the forested zones, including the "rice belt" to the west, in each of the cropping systems where rice was grown. The S1 strain occurred more frequently in the northern Guinean savanna, and only S1 isolates were found further north in the Sahelo-Soudanian zones. In mixed infection, S2 dominated over S1 both in viral capsid and RNA contents under temperature regimes encompassing those observed in savanna and forested zones of Côte d'Ivoire. There was no evidence of interactions in virus accumulation between the West African strains S1 or S2 with the more distantly related East African strain S4. Field trials emphasized the impact of RYMV, which induced yield losses of 40 to 60% in several widely grown cultivars of Oryza sativa indica and O. sativa japonica. We report the high resistance of the O. indica cv. Gigante under field conditions which was apparent with all the S1 and S2 isolates tested. Responses to RYMV infection of several cultivars were isolate dependent. With most differential cultivars, responses were not strain specific, with the exception of the O. japonica cv. Idsa6, in which the S2 isolates always induced higher yield losses than the S1 isolates.

Evidence of the Presence of Two Serotypes of Rice Yellow Mottle Sobemovirus in Côte d'Ivoire

Serological variability of isolates of rice yellow mottle virus (RYMV) collected in Cote d'Ivoire was assessed by immunological tests with polyclonal and monoclonal antibodies (MAbs). Two serotypes (named S1 and S2) were distinguished. The S1 isolates had common epitopes which were absent in S2 isolates, whereas they lacked epitopes shared by S2 isolates. There was no evidence of S1 and S2 mixtures, although S1 and S2 isolates were sometimes found in nearby sites. Serotype S2 was more prevalent in Cote d'Ivoire than S1, and was in a large majority in the centre and the south of the country. By contrast, S1 occurred more widely in the north. S1 isolates were also found in neighbouring countries at the north of Cote d'Ivoire. In tests with monoclonal antibodies, three additional serotypes were found, one in West-Africa and two in East-Africa. Using the primers developed against an S2 isolate from Cote d'Ivoire, all S2 but not the S1 isolates were transcribed and amplified by RT-PCR, and another set of primers was developed to amplify S1 isolates. S1 and S2 have different biological properties, and competition between isolates of the two strains was apparent resulting in S2 dominance over S1. This was assessed using S1 and S2 strain specific MAbs, and it occurred whatever the pattern of inoculation or the rice variety tested. Differences in pathogenicity and virus titre did not account for strain competition, as there was no relation between symptom severity, virus content and serotype of the isolates in Oryza sativa indica cultivars.

Geographic distribution of vacA allelic types of Helicobacter pylori

Background & Aims: Distinct allelic types of Helicobacter pylori vacA have been defined. The geographic distribution of vacA alleles and cagA was assessed in this study. Methods: A total of 735 cultures from patients in 24 countries were analyzed by polymerase chain reaction and reverse hybridization on a line probe assay (LiPA). Results: In 124 (16.9%) of the 735 cultures, multiple vacA genotypes were detected, permitting analysis of 611 strains. In Europe, a distribution gradient of s1 subtypes was observed. In northern and eastern Europe, 89% were subtype s1a. s1a and s1b were equally present in France and Italy, whereas in Spain and Portugal 89% of strains were subtype s1b. s1a and s1b were approximately equally prevalent in North America. In Central and South America, virtually all s1 strains were subtype s1b. Subtype s1c was observed in 77% of the s1 isolates from East Asia. m1 and m2a have equal presence, except on the Iberian peninsula and in Central and South America, where m1 (86.2%) is more prevalent than m2 (13.8%). Subtype m2b was found exclusively among East Asian s1c strains. In all parts of the world, vacA s1/ cagA-positive genotypes were associated with peptic ulcer disease ( P < 0.001). Conclusions: These data indicate a geographic distribution of H. pylori genotypes and aid in understanding the relationship of H. pylori with disease. GASTROENTEROLOGY 1999;116:823-830

Comparative Movement Speed of Pathogenic and Nonpathogenic Isolates of Bursaphelenchus Nematodes

Using a newly devised simple apparatus, comparative study was made on the movement speed of three Bursaphelenchus isolates : S1, a pathogenic isolate of Bursaphelenchus xylophilus ; S0, a nonpathogenic isolate of B. xylophilus ; M, a nonpathogenic isolate of B. mucronatus. Among these isolates, the M isolate moved fastest through the interspace between glass beads in the apparatus at all nematode densities examined. The S1 isolate moved slightly slower than S0 isolate at low densities, however, the former moved more quickly at high densities. Generally, the time required for the half number of nematodes to pass through the apparatus doubled when the interspace between beads was reduced by half. The threshold low temperature for movement was lowest in the M isolate, followed by the S1 and S0 isolate. Regarding the S1 and M isolates, the threshold low temperature for movement was lower than those for development.

Satellite Nature of the Viroid-like RNA-2 of Solanum Nodiflorum Mottle Virus and the Ability of Other Plant Viruses to Support the Replication of Viroid-like RNA Molecules

SUMMARY The stock culture of solanum nodiflorum mottle virus (SNMV) was freed from RNA-2 by passage through single lesions induced in inoculated leaves of Nicotiana debneyi by dilute inocula of partially purified SNMV RNA-1. This isolate (S1) was indistinguishable serologically and in symptomatology from the stock culture of SNMV. Using a sensitive bioassay for detecting RNA-2, no SNMV RNA-2 was found in RNA from particles of the S1 isolate purified after three successive passages in Nicotiana clevelandii. Addition of SNMV RNA-2 (which is not infective alone) had little or no effect on the infectivity of S1 RNA but restored the RNA content of particles to that found in the stock culture (RNA-1 and RNA-2). However, S1 did not support the replication of the RNA-2 from lucerne transient streak virus (LTSV). The possible interaction of the RNA-2 species from LTSV and SNMV with the genomes of other plant viruses was tested by mixing the RNA-2 species with nucleic acid from 11 other viruses. The survival of RNA-2 activity on inoculated leaves for up to 15 days complicated the interpretation of the results of these tests but a small amount of LTSV RNA-2 and SNMV RNA-2 was obtained only from particles of turnip rosette virus purified from plants inoculated with the relevant RNA mixtures. These and other data suggest that these RNA-2 molecules with physicochemical properties similar to viroids found in particles of some sobemoviruses are satellite RNA species whose multiplication is assisted by some, but not all, of the viruses in this group.