MOSP - Macao Scientific Publishers

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Increasing the bioethanol yield in the presence of furfural via mutation of a native strain of Saccharomyces cerevisiae

Rahimian Zarif Bahareh* and Azin Mehrdad

Abstract: High ethanol yield is a desired property of industrial yeast strains. A significant problem in fermentative conversion of lignocellulosic materials to ethanol is the formation of furfural and hydroxymethylfurfural (HMF), which are formed during acid hydrolysis of lignocellulose. Furfural has been known to create strong inhibition in metabolism of the yeast Saccharomyces cerevisiae. In this article, the result of random mutagenesis of a native strain of S. cerevisiae by ultra violet (UV) light and nitrous acid is presented. By screening the cells in the presence of furfural, a potent mutant was selected which produced 36.7% more bioethanol than the parent strain, in the presence of 0.2% (v/v) furfural.[...] Read More.

Keywords: Bioethanol, furfural, mutation, nitrous acid, Saccharomyces cerevisiae PTCC 5315, UV radiation.

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Continuous butyric acid production by corn stalk immobilized Clostridium thermobutyricum cells

Wei Li, Hui-Juan Han and Chun-hui Zhang*

Abstract: Corn stalks were used as a support to immobilize Clostridium thermobutyricum in a fermentation process for butyric acid production. The effects of pH and acetic acid concentration on butyric acid production were examined in a steady- state 25-day continuous flow operation. A metabolic shift was induced by changing pH of the medium. The maximum and the minimum ratio of butyric acid and acetic acid produced in the fermentation process were achieved at pH 7.0 and 5.0, respectively, and the maximum yield of butyric acid was observed at pH 6.0. The addition of acetate in the medium has resulted in an increased butyric acid final concentration. The maximum total butyric acid concentration of 15.82 g/l was obtained at pH 6.0 with 10 g/l acetic acid concentration in the medium. The cell adsorption and morphology change during the growth phase on corn stalk support were examined by the scanning electronic microscope (SEM).[...] Read More.

Keywords: Butyric acid, corn stalk, immobilized cells, Clostridium thermobutyricum.

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Isolation and characterization of antagonistic bacteria against fusarium wilt and induction of defense related enzymes in banana

J. B. Sun, M. Peng*, Y. G. Wang, P. J. Zhao and Q. Y. Xia

Abstract: Fusarium wilt caused by Fusarium oxysporum is considered a fatal disease to bananas. Chemical control of Fusarium wilt in bananas has received little efficiency. Alternatively, biological control is a viable strategy against soil-borne diseases. The objectives of this research were to isolate antagonistic bacteria and investigate the possible mechanisms against Fusarium wilt. An antagonistic Bacillus strain, termed KY-21 against F. oxysporum f. sp. Cubense was isolated from the soil of banana’s rhizosphere by dual culture. The strain was identified as Bacillus subtilis according to the characteristics of its morphology and by homology analysis of its 16S rDNA sequence. Mycelium growth of the pathogen was seriously inhibited after treatment with the fermentation filtrate of KY-21. Observation revealed that the tips of the hypha were deformed into spherical structures that were remarkably constricted. The strain KY-21 displayed a good ability to colonize and can transfer into banana tissues. The activities of polyphenol oxidase (PPO) and peroxidase (POD) in bananas showed an increase after inoculated with KY-21, compared to control. In vivo biocontrol assays showed a significant reduction in wilt index and vascular discoloration. These results indicated that the antagonistic mechanisms against Fusarium wilt were involved in the inhibition of mycelial growth and the improvement in activity of defense related enzymes.[...] Read More.

Keywords: Fusarium oxysporum f. sp. Cubense, antagonistic bacteria, screen, colonization, enzyme activity.

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Complement C1, C3 and C4 levels in sera of leishmaniasis cases in Turkey

Full Length Research Paper

Abstract: Leishmaniasis is still a problem for many countries including developed ones. The subgroups of the serum complements have significant roles on the onset of the infection. The aim of this study was to determine the serum complement (C1, C3, C4) levels of cases with definite diagnosis of leishmaniasis and compare them with healthy controls. The study group included 43 visceral leishmaniasis (VL) and 13 cutaneous leishmaniasis (CL) cases. Two control groups were formed for the study. The first control group included 50 individuals of the same age group having no health complaints, admitted for routine control and found to be serologically negative. The second control group included 28 individuals, consistent with the diagnostic criteria of VL. The serum complement levels of C1, C3 and C4 were measured by the nephelometric method. The average levels of C1 were found to be high in VL cases (78.98%) and low in CL (41.69%) group, which was statistically significant (p=0.011). In addition, the average levels of C3 were high in CL group (96.08%) and low in VL group (62.00%), which was also statistically significant (p=0.010) . C4 levels were found to be high in the control group, while similar in VL and CL groups. C1, C3, C4 levels were found to be lower in the first control group of healthy individuals. The levels of the subgroups of complement system show statistically significant in both VL and CL cases, which suggested that they could be useful in verifying the results of the serological examinations.[...] Read More.

Keywords: Leishmaniasis, complement levels, C1, C3, C4.

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Recombinant matrix extracellular phosphoglycoprotein (MEPE) can promote mineralization in vitro

Full Length Research Paper

Abstract: The matrix extracellular phosphoglycoprotein (MEPE) gene is highly expressed in tumors that cause oncogenic hypophosphatemic osteomalacia (OHO). MEPE is also known as one of the bone-tooth matrix proteins and is associated with bone and teeth mineralization. We developed a rabbit polyclonal antibody directed against recombinant human MEPE after cloning its cDNA from the cDNA library of a human brain cDNA library. Using this anti-body, we analyzed the distribution of MEPE in dog dental germ tissue by immunohistochemistry. In these specimens, MEPE was predominantly expressed by odontoblast cells and predentin, but not by dental pulp cells. Furthermore we used von kossa staining. And the results suggested that MEPE could induce mineralization and we propose that this protein has a potential effect on dental rehabilitation.[...] Read More.

Keywords: Matrix extracellular phosphoglycoprotein, mineralization Von kossa.

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The presence of Campylobacter jejuni in broiler houses: Results of a longitudinal study

Yavuz Cokal*, Vildan Caner, Aysin Sen, Cengiz Cetin and Murat Telli

Abstract: In this study, the presence of Campylobacter jejuni in water lines of commercial broiler house and its role in the epidemiology of the infection of broiler flocks was investigated. The study was done in three sequential commercial broiler flocks previously known to be infected with C. jejuni in two poultry houses with different water sources. C. jejuni was identified in drinking water and drinking nipple swab samples in water-line samples from both houses. Fresh fecal dropping samples were taken from broiler flocks for determination of C. jejuni-carriage. Twenty and 130 C. jejuni isolates were recovered from water-line system and fecal dropping samples, respectively. A total of 150 C. jejuni isolates were genotyped by pulsed-field gel electrophoresis (PFGE) with SmaI digestion and 9 distinct PFGE patterns were identified. Six and 5 different PFGE types were identified in houses 1 and 2, respectively. C. jejuni isolates, recovered from water lines samples, were genotypically similar to the isolates from fresh fecal dropping in both houses. These results showed that C. jejuni water-line contamination was related to flock contamination and could help to continuously make it infected with C. jejuni.[...] Read More.

Keywords: Campylobacter jejuni, broiler, water, pulsed-field gel electrophoresis.

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Fibrolytic potential of spent compost of the mushroom Agaricus bisporus to degrade forages for ruminants

M. Ayala, S. S. González-Muñoz* J. M. Pinos-Rodríguez, C. Vázquez, M. Meneses, O. Loera and G. D. Mendoza

Abstract: To evaluate the fibrolytic potential to degrade forages, extracts from spent compost of Agaricus bisporus (SCAB) were evaluated in vitro. Firstly, SCAB was cultivated for 50, 60 and 90 days (culture stage) and enzyme activity was evaluated. The highest cellulase activity was at 60 days; xylanase activity was not affected by culture stage and laccase activity increased as culture stage increased. Secondly, extracts of SCAB cultivated for 60 days were preserved by refrigeration, freezing, freeze-drying, refrigeration + benzoic acid, freezing + benzoic acid, freezing + glycerol, or freezing + benzoic acid-glycerol and then fibrolytic activity was evaluated. The highest fibrolytic activity was shown by SCAB frozen with addition of either glycerol or benzoic acid, or freeze- dried. Finally, effects of SCAB as an additive to enhance ruminal degradation of alfalfa hay, Taiwan grass, barley straw, and spent compost of A. bisporus were evaluated. Soluble fraction of dry matter of alfalfa and potential degradation of dry matter of Taiwan grass and barley straw were increased by SCAB. It is concluded that SCAB showed a noticeable fibrolytic activity which might increase degradation of forages in the rumen.[...] Read More.

Keywords: Agaricus bisporus, degradation, fibrolytic enzymes, forages, ruminants.

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The effect of soil water potential on survival of fecal coliforms in soil treated with organic wastes under laboratory conditions

Ali Akbar Safari Sinegani* and Javad Maghsoudi

Abstract: Pollution caused by animal wastes has become a great problem in many countries. The objective of this study was to test the effects of water potential on survival of fecal coliforms in a soil treated with 3 manures. A semiarid soil was treated with raw cow and poultry manures (CM and PM) and sewage sludge (SS) at a rate of 20 g kg-1 (dry weight basis). Three water potentials established for soil incubation were: Saturation (SAT, 0 bars), field capacity (FC, -0.3 bars), and permanent wilting point (PWP, - 15 bars) . Fourth irrigation treatment was drying-rewetting cycle (DWC) between -0.3 to -15 bars. Colony forming units of Escherichia coli and fecal coliforms on EMBA (eosin methylene blue agar) were counted during soil incubation. The population of E. coli was higher in the soils treated with CM but the populations of lactose positive and negative coliforms were higher in the soils treated with PM. The populations of E. coli and other fecal coliforms were significantly higher in the soils incubated in SAT compared to those in soils incubated in other water potentials especially in the early stages of soil incubation. The populations of fecal coliforms were decreased significantly with increasing time of incubation. Survival of E. coli were near 40 days in the soils treated with PM and SS. E. coli could survive in the soils treated with CM and incubated in SAT and PWP for more than 90 days may be due to low level of negative interactions in these unsuitable water conditions.[...] Read More.

Keywords: Organic wastes, soil water potential, Escherichia coli, fecal coliforms, survival, incubation.

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A novel vector for expression cloning of large numbers of polymerase chain reaction products in Pichia pastoris

Dongming Lan, Wenkai Wang, Lijuan Sun, Yonghua Wang* and Bo Yang

Abstract: We described construction of a novel vector, pAOX-HT, for direct cloning of polymerase chain reaction (PCR) amplified fragments and expression in Pichia pastoris. The pAOX-HT serves both as a T-vector and expression vector and can be generated from a parent plasmid by digestion with restriction enzyme XcmI. To minimize the non-recombinant background, the parent vector pAOX-HT-BSK was designed to contain a large insert. The cloning efficiency was above 95% when tested with PCR products. The linearized pAOX-HT was engineered to harbor a potential AflII site (CT) upstream of the T/A cloning site. An AflII site was reconstructed when the PCR product with 5’-TAAG sequence was ligated into the T/A cloning site. Taking advantage of this property, we digested the ligated products by restriction enzyme AflII before transformation to eliminate the clones containing inserts with undesired orientation. By using pAOX-HT vector, the lipase B gene from Candida Antarctica was efficiently cloned and expressed in P. pastoris and the recombinant protein was purified by affinity chromatography. These results demonstrate that the pAOX-HT might serve as a useful tool for gene function study.[...] Read More.

Keywords: T vector, expression vector, yeast expression, restriction endonuclease digestion.

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Identification and quantitation of conjunctival aerobic bacterial flora from healthy residents at different ages in Southwest China

Jing Liu, Jing Li, Jian Huo and Hanping Xie*

Abstract: To identify and quantitate conjunctival aerobic bacterial flora from healthy residents of three age groups in Chongqing city, Southwest China. Samples taken with moist swabs from the lower fornix of bilateral eyes of 33 children (9.85 ± 0.57 years old), 31 youths (21.23 ± 0.88 years old), and 30 elders (72.97 ± 4.94 years old) respectively were tested for bacterial cultures. Positive cultures were identified and colony forming units (CFUs) were counted. Bacterial quantity was expressed as the number of CFUs divided by the weight difference of each sample transport swab-tube measured before and after the sample collection. The elders showed a higher isolation frequency (93.33%) of conjunctival aerobic bacteria than that of children (45.45%) and youths (50.00%), (P[...] Read More.

Keywords: Conjunctival sac, aerobic bacteria, age, quantitative analysis, microecology.

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