Advanced Journal of Microbiology Research

Advanced Journal of Microbiology Research Vol. 2017

Available online at http://internationalscholarsjournals.org/journal/ajmr

© 2017 International Scholars Journals

Full Length Research Paper

Expression and characterization of the recombinant Trichoderma virens endochitinase Cht2

S. A. A. Al-Rashed¹, F. D. A. Bakar¹, M. Said², O. Hassan², A. Rabu¹, R. M. Illias³ and A. M. A. Murad¹*

¹School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia.

²School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia.

³Department of Bioprocess Engineering, Faculty of Chemical and Natural Resources Engineering, University Teknologi Malaysia, 81310 Skudai, Johor, Malaysia.

Accepted 4 August, 2017

Abstract

An endochitinase, Cht2, from Trichoderma virens UKM1 was expressed in the methylotrophic yeast Pichia pastoris, and its biochemical properties were characterized. Both the cht2 gene and its cDNA have been cloned and sequenced, the endochitinase gene cht2 encodes 321 amino acids from an open reading frame comprised of an 1169 bp nucleotide sequence separated by three introns. Cht2 is predicted to be an extracellular enzyme due to the presence of a signal peptide of 20 amino acids. Cht2 cDNA was cloned into the pPICZaC expression vector under the regulation of a methanol-inducing promoter and transformed into P. pastoris X33. Expression in P. pastoris showed that the recombinant Cht2 was secreted into the culture medium with a protein size of approximately 35 kDa when induced with 0.5% methanol. Biochemical characterization of the partially purified enzyme showed a specific enzyme activity of 1.34 U/mg towards colloidal chitin at a pH of 6.0 and at a temperature of 35°C. The enzyme showed optimal activity at this pH and temperature and also showed higher affinity toward colloidal chitin in comparison to glycol chitin. It is stable in the pH range of 5.0 - 7.0 and in the temperature range of 30 - 55°C, where it retained more than 70% of its residual activity.

Key words: Endochitinase, Trichoderma virens, recombinant, characterization.

Advanced Journal of Microbiology Research Vol. 2017

Available online at http://internationalscholarsjournals.org/journal/ajmr

© 2017 International Scholars Journals

Full Length Research Paper

Analysis of early-stage infection risk factors after living donor liver transplantation in 25 children

Lan Liu¹*, Xuesong Peng¹, Lijuan Chu¹, Qian Liu², Juan Xiong¹, Chunmei Jing¹, Yongwu Xia¹ and Yu Shi¹

¹Clinical Laboratory Center of Children’s Hospital of Chongqing Medical University, Chongqing 400014, China.

²Xiangya School of Medicine, Central South University, Hunan 410013, China.

Accepted 28 June, 2017

Abstract

Living donor liver transplantation (LDLT), which was first demonstrated in 1989, has now been widely used to cure many late-stage hepatic diseases and has achieved huge success, especially in the pediatric field. However, accumulated studies indicate that early-stage infection after LDLT is the main cause leading to its failure and the death of the patient. Here, we retrospectively analyzed 25 cases (from 2006 to 2009) of infections of children in our hospital, underwent LDLT and their correlated factors. To identify the factors most closely related to early stage infection, we categorized early stage infection levels as either mild, moderate or severe and we compared their related risk factors, including total length of stay in hospital (TLSH), length of stay in the intensive care unit (LSI), duration of catheterization (DC), length of pre-/post-operative antimicrobial agent application, length of immuno-suppressant agent application (LISA) and underlying diseases postoperatively. The results revealed the following. (i) Of 25 patients, 24 recipients were infected to various extents: 6 cases of mild infection, 14 cases of moderate infection and 4 cases of severe infection (one patient died). (ii) TLSH, LSI and durations of preoperative (DPAA) and postoperative (DPOAA) antimicrobial agent application were statistically different between the severe and moderate infection groups (P = 0.03 (TLSH), 0.004 (LSI), 0.003 (LAPP), 0.005 (DPOAA). (iii) Between the severe and mild infection groups, the TLSH (P = 0.016), LSI (P = 0.015), DAPP (P = 0.007) and DPOAA (P = 0.001) were also significantly different. (iv) In the case of LISA, only methylprednisolone (P = 0.01) and the calcineurin inhibitor ciclosporin A (P = 0.009) showed statistically significant differences between the moderate and mild infection groups. (v) Biliary atresia is the predominant underlying liver disease. (vi) In contrast to previous findings, there was no significant difference in DC among the three infection groups. (vii) Of all the 25 patients, 24 survive till now and the only one died was diagnosed as portal vein thrombosis (PVT) combined with high white blood count (>30 x 10⁹/l) in venous blood. DPAA, DPOAA and biliary atresia are the risk factors most closely related to infection during liver transplantation in children, an observation worthy of future investigation. To avoid long term DPAA and long term DPOAA induced early severe infection, nosocomial infection control and drug resistant bacteria monitoring are worthy to be concerned after LDLT in children.

Key words: Living donor liver transplantation, risk factor, children.

Advanced Journal of Microbiology Research Vol. 2017

Available online at http://internationalscholarsjournals.org/journal/ajmr

© 2017 International Scholars Journals

Full Length Research Paper 

Characterization of Enterococci isolated from Moroccan dairy products

Naoual Jamaly^1,2, Abdelaziz Benjouad², Roberta Comunian³, Elisabetta Daga³ and Mohammed Bouksaim¹*

¹Laboratory of Food Technology and quality, Safety/food quality/environment, CRRA, INRA, Avenue Ennasr, BP 415 RP, Rabat, Morocco.

²Laboratory of Biochemistry and Immunology, Faculty of Sciences, Agdal, University of Mohammed V, 4 Avenue IbnBattouta, BP 1014 RP, Rabat, Morocco.

³Dipartimento per la Ricerca nelle Produzioni Animali, AGRIS Sardegna. Loc. Bonassai km 18.600, I-07040 OLMEDO (SS), Italy.

Accepted 19 July, 2017

Abstract

Twenty three Enterococcus durans isolates collected from Moroccan dairy products were identified by species-specific PCR and their technologically relevant biochemical properties were studied. According to biochemical activities, the majority of the strains displayed weak acidification and autolysis activities in milk. In contrast, they showed high extracellular proteolytic activity. All isolates produced exopolysaccharides and most of them could metabolize citrate and tolerate a high concentration of nisin. Absence of vancomycin resistance and haemolytic activity may suggest the use of these isolates as adjunct starters in food fermentations process.

Key words: Enterococcus durans, Moroccan dairy products, species-specific PCR (Polymerase chain reaction), biochemical properties, adjunct starter cultures.

Advanced Journal of Microbiology Research Vol. 2017

Available online at http://internationalscholarsjournals.org/journal/ajmr

© 2017 International Scholars Journals

Full Length Research Paper

Isolation and partial characterization of a bacteriophage infecting the shrimp pathogen Vibrio harveyi

Parichat Phumkhachorn and Pongsak Rattanachaikunsopon*

Department of Biological Science, Ubon Ratchathani University, Warin Chamrap, Ubon Ratchathani 34190, Thailand.

Accepted 29 April, 2017

Abstract

A bacteriophage infecting Vibrio harveyi was isolated from shrimp pond water, it was designated PW2. It infected all strains of V. harveyi but not other bacteria used in this study. The phage adsorption rate increased rapidly in the first 15 min of infection to 80% and continued to increase to 90% within 30 min of infection. The stability of phage PW2 was dependent on temperature and pH. It was inactivated by heating at 90°C for 30 min and by treating at pH 2, 3, 11and 12. From its one step growth curve, latent and burst periods were 30 and 120 min, respectively with a burst size of about 78 plaque-forming unit (pfu) per infected center. As analyzed by transmission electron microscopy, phage PW2 had an icosahedral head (50 ± 3.8 nm in diameter) with a noncontractile tail of 136 ± 6.2 nm long and 11 ± 0.5 nm wide and belongs to the Siphoviridae family. Six structural proteins (75, 60, 35, 30, 20 and 15 kDa) were detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis, its genome was found to be double stranded DNA with an approximate size of 46 kb.

Key words: Bacteriophage, shrimp, Vibrio harveyi.

Advanced Journal of Microbiology Research Vol. 2017

Available online at http://internationalscholarsjournals.org/journal/ajmr

© 2017 International Scholars Journals

Full Length Research Paper

Protective effect of Glycyrrhiza glabra polysaccharides against carbon tetrachloride-induced liver injury in rats

Liang Renjie*, Shi Shidi and Sun Changsen

School of Life Science, Taizhou University, Zhejiang, 317000, P. R. China.

Accepted 5 July, 2017

Abstract

The objective of the present study was to investigate potential of Glycyrrhiza glabra polysaccharides to offer protection against acute liver injury in rats. Rats were administered a single oral dose carbon tetrachloride (CCl₄, 640 mg/kg b.w., 1:1 in groundnut oil) and sacrificed 7 days of post-treatment. Hepatic damage was assessed by employing biochemical parameters. Our results demonstrated that treatment of rats with G. glabra polysaccharides significantly prevented the increased activities of and aspartate aminotransferase (AST), alanine aminotransferase (ALT), ALP and LDH in serum. G. glabra polysaccharides treatment also restored CCl₄-induced altered caspase-3, TGF- 1 and TGF- 1 mRNA. Our findings provide evidences to demonstrate that G. glabra polysaccharides treatment significantly offsets CCl₄-induced liver injury in rats.

Key words: Glycyrrhiza glabra polysaccharides, rat, TGF- 1 mRNA, aspartate aminotransferase (AST), carbon tetrachloride.

Advanced Journal of Microbiology Research Vol. 2017

Available online at http://internationalscholarsjournals.org/journal/ajmr

© 2017 International Scholars Journals

Full Length Research Paper

Mycoflora of stored “Ofada” and “Abakaliki” rice in Lagos and Ogun States, Southwestern Nigeria

Y. M. Somorin^1* and S. A. Bankole²

¹Department of Microbiology, University of Agriculture, Abeokuta, P. O. Box 851, Ota, Ogun State, Nigeria.

²Department of Microbiology, Olabisi Onabanjo University, P. M. B. 2002, Ago-Iwoye, Ogun State, Nigeria.

Accepted 22 June, 2017

Abstract

The presence of fungal contaminants in Ofada and Abakaliki rice varieties under storage in Lagos and Ogun States, Nigeria were examined. The fungal species isolated from the Ofada rice were Actinomycetes spp., Aspergillus flavus, Aspergillus niger, Aspergillus tamarii, Cladosporium sphaerospermum, Fusarium compacticum, Fusarium oxysporum, Fusarium proliferatum, Penicillium oxalicum, Rhizopus nigricans, Rhizopus oryzae and Saccharomyces cerevisiae. The Abakaliki rice was contaminated with A. flavus, A. niger, A. tamarii, F. compacticum, F. oxysporum, F. proliferatum, Penicillium citrinu, P. oxalicum, R. nigricans, R. oryzae and S. cerevisiae. A. niger (80%) was the predominant fungal species while Actinomycetes spp. (6.7%) was the least isolated. Some of these fungi are known to produce mycotoxins which have several health and economic implications. The presence of such species as seen in this study may show a potential risk of mycotoxin contamination in Ofada and Abakaliki rice varieties.

Key words: Fungi, contaminants, Ofada, Abakaliki, rice, mycotoxin, mycoflora.