MOSP - Macao Scientific Publishers

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Isolation and characterization of a psychrophilic bacterium producing cold active lactose hydrolyzing enzyme from soil of Mt. Himalaya in Nepal

E. S. Nam, Y. H. Kim, K. H. Shon, and J. K. Ahn*

Abstract: Psychrophilic bacteria, which grew on lactose as a carbon source, were isolated from soil of Island Peak area at Mt. Himalaya in Nepal, and identified. 148 bacterial isolates were isolated via X-gal hydrolysis on plate. Among these, three isolates, referred to as KNOUC 401, 402 and 403, displayed good cold-adapted growth and activity for hydrolysis of o-nitrophenyl- -D-galactopyranoside (ONPG) and lactose in cell free extracts. Strain KNOUC403 showing negative activity in -hemolysis was selected and identified. The strain was gram-positive bacilli, non-motile, catalase-positive and aerobic. Optimum growth was done at 20°C and pH 6.5~6.8. Anteiso-C15:0 (68.14%) was predominant in the fatty acid composition of cell. The physiological and biochemical properties, cellular fatty acid composition and sequence of 16S rDNA, suggest that strain KNOUC403 indicate a taxonomic affiliation to Arthrobacter psychrolactophilus. The optimal conditions for ONPG hydrolysis of cell free extracts from the strain were 15°C and pH 6.0, and the enzyme was stable at 4°C for 42 h. Zymogram assay of cell free extract from the strain in nondenaturing polyacrylamide gel showed a distinct band of X-gal hydrolysis.[...] Read More.

Keywords: Psychrophilic bacteria, Arthrobacter psychrolactophilus, cold-active lactose hydrolyzing enzyme, Mt. Himalaya.

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Full Length Research Paper

Abstract: Enduro hand sanitizer is a new disinfecting agent that has recently been introduced as an effective antibacterial, antifungal and antiviral agent. Considering the importance of infection control in dentistry, this study aimed to evaluate the antimicrobial effects of the foam and its ability to disinfect dental surfaces and instruments. An experimental study was designed to evaluate the microbial load of 50 samples which were obtained randomly from dental surfaces and instruments before and after application of the disinfecting foam. All samples were cultured in blood agar and nutrient agar culture media and incubated at 37°C for 24 h. Colony count was subsequently performed after an additional 24 h. Furthermore, to evaluate the efficacy of the foam on different bacterial species, a blank disc was coated with foam and approximated with the bacteria. The clear zone around each disc was measured and reported (mm) after 48 h. The significance of differences between the data retrieved before and after applying the foam was determined using the non parametric Chi-square test. None of the species were colonized after the application of the foam. It was also shown to significantly reduce the colonization of resistant bacterial strains and the standard microbial species (P[...] Read More.

Keywords: Antibacterial, disinfecting agent, dental instrument.

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Rapid detection of Salmonella species using an improved gel-based DNA microarray method

Xuhong Ye, Yiming Wang, and Xiangui Lin,*

Abstract: Salmonella, widely distributed in nature, is a great human and animal health hazard of a class of pathogens. Culture-based methods may require many days to detect Salmonella. Traditional microbiology could advantageously be replaced by DNA microarray technology. We described an improved 3-D polyacrylamide gel-based DNA microarray assay based on gyrB gene (DNA gyrase B subunit gene) sequences that can be used for the identification of Salmonella species. Primers specific for a gyrB gene region common to all 13 samples were synthesized and used for PCR amplification of purified DNA. An oligonucleotide probe for specific gyrB gene regions was developed for the identification of 7 Salmonella species. Acrylamide-modified oligonucleotides solutions containing acrylamide monomer, glycerol, APS and probe were prepared at the desired concentration. The solutions were spotted on the modified glass slide by ink jet using a microarrayer and then the slide was transferred to a vacuum chamber with TEMED, after that the slide was used for hybridization with fluorescently labeled ssDNA derived from amplified sample DNA to yield a pattern of positive spots. This microarray produced unique hybridization patterns for species of Salmonella and could differentiate closely related bacterial species. The sample preparation and microarray method used in this study increased sensitivity and reduces time-to-result for detection of Salmonella. The described method allowed microarray monitoring for Salmonella contamination of food and manure for aquaculture.[...] Read More.

Keywords: Salmonella, gyrB gene, PCR, DNA microarray, TEMED.

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Molecular study for detection of Feline Leukemia Virus (FeLV) in Iranian cats

Farzad Shahrani, Abbas Doosti,* and Asghar Arshi

Abstract: Feline leukemia virus (FeLV) is a retrovirus that infects cats. This infectious disease is a form of cancer of blood cells called lymphocytes. FeLV occurs in nature not as a single genomic species but as a family of closely related viruses. The aim of present study was to detect FeLV in Iranian domestic cats Reverse transcription polymerase chain reaction (RT-PCR). Fifty six blood samples were tested for FeLV using molecular techniques and out of 56 samples overall frequency of FeLV infection was 2.2%. The results showed that FeLV is a specific infection and the other common feline infectious pathogens and FeLV seem to be endemic in Iranian cats Vaccination and testing programs have proven to be effective in decreasing FeLV infection in Iran and may potentially totally eliminate it at least in other countries.[...] Read More.

Keywords: Feline leukemia virus, PCR, Iranian domestic cats.

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Aspects of bacterial colonization in newborn babies

Fariba Heshmati*, Seyeed Amir Yazdanparast , Seyeed Akbar Moosavi , Hussein Dargahi, and Farnaz Tabibzadeh

Abstract: The study of colonization of microbial flora in neonate is very important and finding the causative agent may lead to explore these infections in neonate. In this research the colonization in neonate was measured at the beginning and a few hours after birth. Sampling was performed in operating room, rooming in and nursery section. Some of the neonates deliver by rapture of membrane in normal way and the other deliver by caesarean section. All the samples which are collected were from these sites: 1 Forehead 2) Oral cavity 3) External ear 4) Auxiliary region 5) Umbilical region 6) Perennial region. Also we had some sampling from health care personnel who are worked in operating room or nursery section. At the time of sampling we used sterile gloves, mask and always sterile sets. Sampling was done by use of sterile swabs which were weltering by sterile phosphate buffer or sterile normal saline.Then this sterile swab scrubbed on the special surface of the body of neonate and directly transferred to BA plate, Mac agar plate, EMB agar plate and Sc agar plate and then streaked on these plates. The regions which were sampled ,numbered by 1 to 6 then in other hours once more the sampling were took place from the same site, therefore we began from number 7 to 12 and according to this method for example sampling from neonate A was showed by A1 to A12. The prevalent microorganisms in oral cavity were as follow: 63.5% GPC, 18.5% GPB and 11% GNC. Staphylococcus epidermidis was the major microorganism found in neonate forehead. No bacteria growth was found in 50% of samples through caesarean section. Staphylococcus and Diphtheroied constitute the highest colonization of neonate skin's microorganisms and their growth rates were low at the onset of the birth, but increased after 12 hours. Colonization of gram-negative bacteria in infant hours after birth considered to be an important issue that was studied in this research. Hence hand washing of health-care personnel’s can reduce such bacteria in infant. There was a significant decrease in (GNB) number due to hand washing, hence application of disinfectant solution in hand washing play an important role in controlling microorganisms in care unites.[...] Read More.

Keywords: Colonization, GPC (Gram- positive cocci), GPB (Gram-positive bacilli), GNC (Gram- negative cocci), GNB (Gram- negative bacilli), Microorganism.

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Characterization of thermostable 2-deoxy-D-ribose-5-phosphate aldolase with broad temperature adaptability from Thermococcus onnurineus NA1

Xiao-pu Yin, Qiu-yan Wang, Shu-juan Zhao, Peng-fei Du, Kai-lin Xie, Lihua Yang, Peng Jin, Jin-hua Liu and Tian Xie*

Abstract: The 2-deoxy-D-ribose-5-phosphate aldolase gene from Thermococcus onnurineus NA1 was sub cloned, over expressed in Escherichia coli and purified to apparent homogeneity. Analysis of the sequence of gene revealed an n of 681 base pairs encoding 227 amino acids predicted to yield a protein having molecular mass 25.3 kDa. The enzyme activity was optimal at 60°C and showed broad temperature adaptability, retaining more than 30% of its maximum activity when assayed at 10 to 75°C. The recombinant protein was heat stable; no activity loss was observed even after incubation at 80°C for 10 min. In addition, the thermophilic enzyme showed a remarkable resistance to acetaldehyde; it retained more than 45% activity after exposure for 20 h to 250 mM acetaldehyde at 25°C.[...] Read More.

Keywords: 2-Deoxy-D-ribose-5-phosphate aldolase, thermostable enzyme, broad temperature adaptability.

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Screening of antibiotic sensitivity, antibacterial and enzymatic activities of microbes isolated from ex-tin mining lake

Ong K. S., Chin H. S. and Teo K. C.*

Abstract: Water sample from ex-tin mining lake was collected and cultured on nutrient agar (NA). Morphology characteristics revealed that isolates WL1 and WL4 were Gram-negative cocci and WL3 was Gram-positive cocci. Meanwhile, WL2 and WL5 were Gram-positive bacilli and spore formers. These isolates were screened for their antibiotic sensitivity against 17 types of antibiotics using Kirby-Bauer method. Antibacterial activity against 11 types of indicator bacteria were also tested using agar well diffusion method. The antibiotic susceptibility test demonstrated that all five isolates had high degree of inhibition to five types antibiotics namely amikacin, kanamicin, gentamicin, norfloxacin and tetracycline. Gram-negative cocci WL4 is a multiple resistant isolate that resistant to 10 types of antibiotics. The Gram-positive bacilli WL2 had antibacterial activity against Gram-negative ESCHERICHIA COLI. Enzymatic assay showed that all isolates were proteolytic, lipolytic and phosphatase enzyme producers. Amylolytic activity was absent in all isolates. Protease, leucine arylamidase, alkaline and acid phosphatases, phospholipase esterase and esterase lipase were found in all isolates. The preliminary survey demonstrated that the water environment in the vicinity of Campus Lake is a reservoir of microbial populations. The present work concerns a screening of a few selected isolates with some significance importance in the application of medical and industry fields. In conclusion, the multi resistance isolates were not suitable for industry application due to some facts that it might produce toxic compounds and cause infection. The antimicrobial substance and enzymes produced by the potential isolates could be further screened for clinical application and mass production in industry. However, they must be evaluated for their safety and toxicity to human, animals and the environment.[...] Read More.

Keywords: Nutrient agar (NA), Kirby-Bauer, antibacterial assay, antibiotic susceptibility test, enzymatic assay.

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A simple and efficient method that uses low concentration fetal bovine serum to culture and purify Schwann cells

Han Feng, Qu Wei*, Jiang Huajun, Fu Chongyang, Lu Ming, Zhang Weiguo and Lv Decheng

Abstract: To develop a simple and efficient method for the isolation of highly purified Schwann cells (SCs) from the sciatic nerves of newborn rats, cells were initially cultured in 10% FBS for 6 days, and then cultured in 2% FBS for 6 days. And we used the immunocytochemical characterization, flow cytometry, RT-PCR, to observe the condition of SCs. After the 12-day treatment protocol, we obtained a high yield of SCs with an average purity of 96.9%. Furthermore, the condition of SCs had no change. In our purification protocol, we had shown that our procedures did not alter the cell cycle and neurokines’ secretion. Our simple and efficient method yielded pure and healthy SCs and did not require treatment with anti-mitotic agents or any special equipment.[...] Read More.

Keywords: Schwann cells, cell culture, low fetal bovine serum concentration, tissue engineering, fibroblast.

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Ephedra alata as biologically-based strategy inhibit aflatoxigenic seedborne mold

Al-Qarawi, A. A., Abd_Allah, E. F.* and Hashem Abeer

Abstract: Investigation has been carried out to evaluate the effect of range plant Ephedra alata as biologically-based strategy inhibit growth characters and aflatoxin production (in vitro and in vivo) of Aspergillus flavus. The aqueous extract of E. alata had significant inhibitory potential against growth as well as aflatoxin production by aflatoxigenic seedborne mold (Aspergillus flavus). Moreover, it has been found that, the addition of 1 and 2% (w/w) of plant powder material of E. alata to corn grains and soybean seeds respectively decreased the aflatoxin contamination and improve their nutritional value (total nitrogen content, fiber content, total lipids content and ash content) under storage conditions. The results observed here suggest employment of E. alata as an alternative non-chemical mean to control aflatoxin contamination of fodder in Saudi Arabia.[...] Read More.

Keywords: Biocontrol, Aflatoxins, Aspergillus flavus, Ephedra alata, nutritional value, Saudi Arabia.

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Nigerian phages: The first bacteriophages from Tropical Africa

Adeniran S. Koko, Hans W. Ackermann*, Monisola A. Taiwo and Sunday A. Omilabu

Abstract: Fifteen morphological bacteriophage types were observed in enrichment cultures of sewage, surface water and human feces collected in Lagos, Nigeria. All phages were tailed and belonged to the Myoviridae, Siphoviridae or Podoviridae families. Most phages could be assigned to well-known morphotypes. Ten of them corresponded to phages of enterobacteria or pseudomonads. Four morphotypes (φKZ, T4 and χ, Jersey) prevailed in most samples. Most others occurred in traces only.[...] Read More.

Keywords: Bacteriophages, ecology, identification, morphotypes.

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