MOSP - Macao Scientific Publishers

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Kinetics and thermodynamics of high level Î²-glucosidase production by mutant derivative of Aspergillus niger under submerged growth conditions

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Abstract: Gamma rays mediated mutagenesis and subsequent selection on 2-deoxy-D-glucose developed a highly catabolite de-repressed and stable β-glucosidase (BGL) hyper-producer mutant of local Aspergillus niger NIBGE, which has high potential for industrial applications. The M6 mutant showed highest constitutive production of BGL (14,900 IU/L) on glucose as compared to control (5,900 IU/L). Wheat bran was the best carbon source and BGL production by parent and mutant strain was 16,200 and 29,500 IU/L, respectively. Effect of inoculum density, pH, temperature and wheat bran concentration on the BGL production was determined in terms of kinetic growth parameters, that is, specific growth rate (m), biomass doubling time (td), product yield coefficient with respect to cell mass (Yp/x) and specific rate of product formation (qp). Optimal conditions for BGL production by parent and mutant strain were same: inoculum level= 0.184 mg cells/mL (10% v/v); optimum temperature= 30°C and pH= 5.0; wheat bran= 3% (w/v). The apparent subunit molecular mass of BGL from both strains was also same (130 kDa). Determination of thermodynamic parameters led to consider that the hyper-production of BGL by the mutant was due to decrease in: activation energy (Ea(p)), change in enthalpy (ΔH*(p)) and Gibbs free energy (ΔG*(p)) for product (BGL) formation.[...] Read More.

Keywords: β-glucosidase, Aspergillus niger, activation energy, enthalpy, Gibbs free energy.

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Seroprevalance of Coxiellosis in cows, sheep, goats and humans in Diyarbakir region of Turkey

Neval Berrin Arserim, Simten Ye ilmen, Osman Ya ar TEL, Tuncer Özekinci, Oktay Keskin, Hüseyin Pulat and Aydin Vural

Abstract: This study aims at determining the seroprevalance of Coxiella burnetii in cows, sheep, goats and staff, working in the stock breeding sector in Diyarbakir region. Therefore, C. burnetii antibodies were investigated in sera samples of 612 sheep, 700 goats, 584 cows and 90 staff by enzyme-linked immunosorbent assays (ELISA). In the study, seropositivity was obtained as 25.4, 38.6, 20.0 and 6.6% in sheep, goats, cows and stockbreeding staff, respectively. Consequently, C. burnetii seropositivity, whether in people or in animals, had a ratio that should not be ignored in Diyarbakir region. Abort cases in ruminant should be assessed from the viewpoint of Coxiellosis. Also, people, especially those who are in risk group, should be made to be conscious of Coxiellosis infection, and measures for preventing this illness should be taken.[...] Read More.

Keywords: Cow, Coxiella burnetii, goat, human, seroprevalance, sheep.

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A study of multiple resistance and role of extended spectrum -lactamases in environmental Pseudomonas isolates

Chikwendu C. I.*, S. N. Ibe and G. C. Okpokwasili

Abstract: The activity of 13 antimicrobials was studied, to determine multiple antimicrobial resistances, against 208 Pseudomonas strains (125 Pseudomonas sp and 83 Pseudomonas aeruginosa) isolated from river and aquaculture samples. Isolates were confirmed with API 20 NE. Isolates from both sources reported high resistance rates for similar antibiotics. These were: Ampicillin (100, 100%), cefuroxime (96.8, 81.9%), streptomycin (93.6, 78.6%), cefotaxime (93.6, 77.1%), for river water and aquaculture samples respectively. While resistances were high for ofloxacin, norfloxacine, mezlocillin, ceftazidime, kanamycin and enrofloxacine (70 to 85.5%) among the river water isolates, they were moderate among the aquaculture isolates (50 to 69.4%). Ninety seven (97.2%) percent of isolates from river water and 78.9% from aquaculture were resistant to at least three or more antimicrobials and were termed multi-resistant. Results of plasmid profiling showed the presence of multiple plasmids ranging in size between 639 and 11845 bp. Preliminary tests for -lactamase detection by double-disk approximation were positive with high resistances to imipenem, aztreonam, cefpodoxime and cefotaxime. PCR of amplified genomic DNA was positive for the detection of blaSHV and blaTEM -lactamase genes. However, up to 50% of all isolates tested were found to be resistant to the -lactamase inhibitor of combination amoxicillin+clavulanic acid. The results infer the presence of multi resistant organisms as well as genes conferring -lactamase resistance in environmental samples.[...] Read More.

Keywords: blaSHV, blaTEM, beta-lactamase, multi-resistant, Pseudomonas sp., environmental sources.

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Optimization of the production of exopolysaccharides by Bacillus thuringiensis 27 in sand biological soil crusts and its bioflocculant activity

Z. R. Wang., J. P. Sheng, X. L. Tian, T. T. Wu, W. Z. Liu and L. Shen*

Abstract: To improve the yield of exopolysaccharides (EPS) by Bacillus thuringiensis 27 from sand biological soil crusts in Gurban Tonggut Desert, Xinjiang, China and to analyze its bioflocculant activity, orthogonal matrix method was used and this method enabled us to obtain maximum EPS production. By studying the optimal medium condition of beef extract 3 g/l, peptone 10 g/l, maltose 40 g/l, and NaCl 4g/l we observed that the optimal medium condition was pH 6.0, incolum size 8%, liquid volume 40 ml in 200 ml flak and temperature 28°C. The maximum EPS production was 20.19 g/l which is about five times more than that at the basal condition. Furthermore, results obtained indicated that the flocculation activity of the extracellular polymer can be achieved at over 80.4% in kaolin suspension and this occurred at a concentration of 0.4 mg/l. This paper describes the optimum condition of exopolysaccharides production by Bacillus thuringiensis 27 and showed that exopolysaccharides had high bioflocculant activity. This work provides a scientific foundation to explore new exopolysaccharides and bioflocculation in sand biological soil crusts. Maximum production of exopolysacchaides under the optimal medium and condition can be achieved and exopolysaccharides have high bioflocculating activity in kaolin system.[...] Read More.

Keywords: Biological soil crusts, exopolysaccharides, flocculation, optimization, Bacillus.

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Biopreservative potential of marine lactobacillus spp

K. Indira*, S. Jayalakshmi, A. Gopalakrishnan and M. Srinivasan

Abstract: Bacteriocins are of special interest due to their potential value as natural preservative. The present study is a trial for production of such bacteriocin from a marine Lactobacillus sp. Lactic acid bacteria (LBA) was isolated from fish gut (Mugil cephalus) and prawn muscle (Peneaus monodon) samples and their density were found to be 5.2 x 107 and 6.4 x 107 CFU/g respectively. Various pathogens were isolated from ready to eat pickle samples (bottled). The LAB strains were tested against 10 different commercial antibiotics. Among them Vancomycin was the only antibiotic that showed a minimum of 40% resistance to the LAB strains tested. LAB strains were optimized at different parameters and maximum bacteriocin production was at pH 6, temperature of 35°C, 3.5% of salt concentration, 24th h of incubation period. Bacteriocin produced by these strains were precipitated from the culture filtrate using methanol and TCA which was further dialyzed, centrifuged and lyophilized. Lactobacillus fermentum was selected as the most potential strain for both bacteriocin production as well as antimicrobial activity. sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis proved that the obtained protein is homologous with a molecular weight of 18 kDa. FT-IR spectrum also confirmed the obtained protein as a bacteriocin. The study revealed that Lactobacillus strains of marine origin are having the potential to be used as biopreservatives especially in seafood industries. The production of bacteriocin from L. fermentum was found to be ideal for industrial scale production and commercial utilization.[...] Read More.

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Salt tolerance and mycorrhization of Bacopa monneiri grown under sodium chloride saline conditions

Khaliel A. S.*, Shine K. and Vijayakumar K.,

Abstract: Salinity of soil is a serious problem affecting plant growth and is increasing steadily in many parts of the world, particularly in arid and semi-arid areas. Arbuscular mycorrhiza (A M) is the most wide spread and significant mutualistic fungi having universal in their association including plants of agricultural and medicinal importance. A. mycorrhiza fungi have been shown to promote plant growth and salinity tolerance by various mechanisms. The effects of inoculation with two A. mycorrhizal fungi Glomus mosseae and Glomus intraradices have been investigated on B. monneiri, an important medicinal plant grown with five different levels of salinity (0.40, 80, 120 and 160 mM). Root colonization, leaf chlorophyll content and tolerance of the plants to salinity were determined. The results indicated that the A. mycorrhizal fungi could infect and colonize the roots effectively under high salinity levels and increased chlorophyll content. Dry mass production was significantly enhanced in the inoculated plants and the effect was more evident at the high salinity levels. More over, A. mycorrhizal colonization has increased Na+ and Cl- uptake and reduced rhizosphere NaCl level significantly. A. mycorrhizal association significantly increased tolerance of plants to salinity and was found as an effective measure to enhance establishment of the plant and to decrease soil salinity.[...] Read More.

Keywords: Arbuscular mycorrhiza, Glomus mosseae, Glomus intraradices, Bacopa monneiri, salt tolerance, proline.

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Oral Candida colonization in patients with fixed orthodontic appliances: The importance of some nutritional and salivary factors

Najla Dar-Odeh*, Asem Shehabi, Zaid Al-Bitar , Iyad Al-Omari, Serene Badran, Mahmoud Al-Omiri, Moayyad Naser, Mohammad Al-Beyari and Osama Abu-Hammad

Abstract: We investigated the relationship between fixed orthodontic appliances and oral Candida colonization. The influence of some important nutritional and salivary factors was also investigated. These factors included: hemoglobin, vitamin B12, ferritin and folate levels, salivary flow rate, salivary pH, tobacco smoking and dietary habits. Patients enrolled in this study were adolescent patients aged 12- 18 years who attended the Orthodontics Department/University of Jordan Hospital for the provision of fixed metallic orthodontic appliances. Salivary samples were collected on the first visit prior to bonding, one month and four months later. All patients were investigated for serum vitamin B12, serum ferritin, red-cell folate, complete blood count, salivary pH, and salivary flow rate. Data were obtained from the patients regarding tobacco smoking and dietary habits. We found that Candida colonization did not increase after bonding of fixed orthodontic appliances. None of the local oral factors investigated was correlated with Candida colonization. Only two systemic factors (serum vitamin B12 and red-cell folate) were significantly (P[...] Read More.

Keywords: Oral, Candida, Orthodontic appliances, nutritional deficiency, smoking.

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Enhanced saccharification of steam explosion pretreated corn stover by the supplementation of thermoacidophilic Î²-glucosidase from a newly isolated strain, Tolypocladium cylindrosporum syzx4

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Abstract: Newly isolated fungi, strain Tolypocladium cylindrosporum syzx4 from rotten corn stover, can effectively produced extracellular thermoacidophilic β-glucosidase (syzx4) using agro-industrial residues. After purification and characterization, the β-glucosidase was applied to saccharify steam explosion pretreated corn stover (SCS) with commercial celluclast from Trichoderma reesei when compared with the β-glucosidase (Novo-188) from Aspergillus niger supplementation. Based on the results of the single factor tests, further studied with the response surface methodology (RSM), amid a five level four-factor central composite design (CCD), was designed for the optimal hydrolysis parameters, such as the substrate concentration, pH, temperature and the ratio of celluclast to syzx4, in order to achieve the highest saccharification yield. The substrate concentration and the ratio of celluclast to syzx4 were identified as the limiting factor for the saccharification yield. A maximum saccharification yield of 88.4% was obtained at an optimal hydrolysis condition as follows: substrate concentration (3.05%), pH (3.73), temperature (43.4°C) and the ratio of syzx4 to celluclast [0.91 (18.2 BGU/g substrate): 1 (20 FPU/g substrate)]. The results of a confirmation experiment under the optimum conditions were in agreement with model predictions and they obtained the maximum value of 88.4% saccharification yield. The results suggested that the β-glucosidase (syzx4) from T. cylindrosporum is a good supplementation for the production of reducing sugars from cellulosic biomass.[...] Read More.

Keywords: Saccharification, steam explosion pretreated corn stover (SCS), β-glucosidase, Tolypocladium cylindrosporum syzx4, hydrolysis parameters, response surface methodology (RSM).

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Laboratory analysis of a fatal meningococcal case due to serogroup B Neisseria meningitidis belonging to ST-4821 complex

Zengguo Wang*, Tiejun Hou, Zhijun Chen, Jinsong Li, Shouzhi Wu, Xiaoguang Wei, Yahui Sun and Quanli Du

Abstract: We describle a suspicious Meningococcal death case, confirmating by the laboratory PCR methods. The infection developed rapidly within only 24 h until the patient died. Analyzing the close contact strain and the DNA template extracted from the serum of this patient, we characterized a serogroup B Neisseria meningitidis as the pathogen of this case, which, in terms of sequence typing, belonged to ST-4821 complex which first characterized in serogroup C Neisseria meningitidis as a new unique hypervirulent meningococcal lineages.[...] Read More.

Keywords: Neisseria meningitidis, multilocus sequence typing, serogroup.

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Rapid detection of Salmonella enterica in food of animal origins collected from Riyadh, King Saudi Arabia

Moussa I. M., Ashgan M. H., Mahmoud M. H. and Al-Doss A. A.

Abstract: The present study is aimed to investigate Salmonella species in food of animal origin collected from Riyadh, King Saudi Arabia (KSA) using conventional methods and polymerase chain reaction (PCR), targeting fimA gene specific for members of genus Salmonella. Salmonella isolation revealed 20 Salmonella serovars (8%) out of 250 examined samples. Nine strains (6, 92%) were recovered from 130 examined minced meats and 5 Salmonella strains (8.33%) were recovered from 60 local frozen chickens. Moreover, 6 Salmonella strains (10%) were isolated from 60 examined local chicken cuts. PCR using selective broth culture, Rappaport-Vassiliadis (RV) was used for the detection of different Salmonella species, targeting the fimA gene. All samples revealed positive results with bacteriological examination were positive by PCR -RV, and amplification of 120 bp fragments specific for fimA gene were observed, in addition, to 4 samples (1.6%) previously identified as negative samples with bacteriological examination were positive with PCR using the two primer pairs. The results revealed that the PCR-RV using primers specific for fimA gene could detect more positive samples of Salmonella species than conventional methods for rapid detection of food borne pathogens.[...] Read More.

Keywords: Salmonella species, fimA gene, polymerase chain reaction- Rappaport-Vassiliadis (PCR-RV), frozen chickens, minced meats.

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