Advanced Journal of Microbiology Research

Advanced Journal of Microbiology Research Vol. 2016

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

© 2016 International Scholars Journals

Full length Research Paper

Influences of light and temperature on membrane potential and respiratory viability of an aerobic anoxygenic phototrophic bacterium Erythrobacter sp. JL475

Zaiqing Peng and Nianzhi Jiao*

State Key Laboratory for Marine Environmental Science, Xiamen University, Xiamen, 361005, P. R. China.

Accepted 6 May, 2015

Abstract

Flow cytometry’s (FCM) measurement of membrane potential (MP) and cell respiration viability based on continuous culture was used to investigate the responses of aerobic anoxygenic phototrophic bacteria (AAPB) in the heterotrophic growth and regulation mechanism of photosynthesis to environmental changes. An AAPB strain Erythrobacter sp. JL475 and a non-AAPB strain Erythrobacter sp. JL316 were used as the experimental bacteria, both of which were isolated from the South China Sea. The results showed that light -cultured AAPB showed higher MP and biomass at 10°C, suggesting an obvious stimulation of light on AAPB growth. By contrast, dark-cultivated JL475 had higher MP and biomass at higher temperature (20, 30 and 40°C). The rate of heterotrophic respiration at different temperature environment ranked as follows: dark-cultivated JL316 > dark-cultivated JL475 > light/dark cycling cultivated JL475. Light undoubtedly increased the cell viability of AAPB, especially of apoptosis cells. The CTC⁺% at different carbon concentration ranked as follows: light/dark cycling cultivated JL475 > dark-cultivated JL316 > dark-cultivated JL475. It was concluded that the heterotrophic respiration would played a key role in energy metabolism of AAPB, photosynthesis may provide an advantage for AAPB to survive in a variety of diverse environments.

Key words: Flow cytometry, aerobic anoxygenic phototrophic bacteria, membrane potential, respiration viability, biomass.

Advanced Journal of Microbiology Research Vol. 2016

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

© 2016 International Scholars Journals

Full Length Research Paper

Staphylococcal cassette chromosome mec (SCCmec) analysis and antimicrobial susceptibility profiles of methicillin- resistant Staphylococcus aureus (MRSA) isolates in a teaching hospital, Shantou, China

Qing Peng¹, Bing Hou², Shuqin Zhou³, Yuanchun Huang⁴, Dexing Hua⁵, Fen Yao¹ and Yuan shu Qian¹*

¹Pharmacology Department, Shantou University Medical College, Shantou, Guangdong, 515041, China.

²Clinical Laboratory of Dermatosis Hospital, Shantou, Guangdong, 515041, China.

³Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, 510282, China.

⁴Clinical Laboratory of First Affiliated Hospital, Shantou University, Shantou, Guangdong, 515041, China.

⁵ Clinical Laboratory of Yuebei Hospital, Shaoguan, Guangdong, 512026, China.

Accepted 13 April, 2016

Abstract

Methicillin-resistant staphylococcus aureus (MRSA) infection has now become a major public health concern. The aim of this study is to determine the antibiotic resistance pattern and prevalence of different staphylococcal cassette chromosome mec (SCCmec) types among the MRSA isolates from a teaching hospital in Shantou, China. The minimum inhibitory concentrations (MICs) of seventeen antimicrobial agents against MRSA isolates were determined using the micro broth dilution method. SCCmec types were identified by multiplex polymerase chain reaction (PCR) strategy. The results show that all MRSA isolates were resistant to ampicillin, oxacillin, gentamycin, erythromycin and ciprofloxacin. Fewer than 6% of isolates were resistant to doxycycline, but more than 90% were resistant to cefazolin, cefuroxime, cefotaxime, cefepime, sparfloxacin and tetracycline. There was no minocycline, chloramphenicol or vancomycin resistant. S. aureus was found in this study. SCCmec type III and IIIA were predominant in our study. Our data highlighted that multidrug-resistant strains of MRSA caused severe problems in Shantou, China. However, some of the old agents, such as minocycline, doxycycline and chloramphenicol are highly effective against MRSA isolates.

Key words: Methicillin-resistant Staphylococcus aureus (MRSA), staphylococcal cassette chromosome mec (SCCmec), antimicrobial agent resistance.

Advanced Journal of Microbiology Research Vol. 2016

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

© 2016 International Scholars Journals

Full Length Research Paper

The potential influence of high cholesterol diet-induced oxidative stress on composition and properties of red blood cells in rabbits

Mohamed Anwar K. Abdelhalim

Department of Physics and Astronomy, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia. E-mail: [email protected] or [email protected].

Accepted 16 April, 2016

Abstract

Atherosclerosis and heart diseases are major causes of morbidity and mortality in adults in industrialized nations. The aim of this study was to assess the potential influence of high-cholesterol diet-induced oxidative stress on composition and properties of red blood cells (RBCs) in rabbits. Thus, percentage of hematocrit, RBCs, white blood cells (WBCs) and platelets counts, total cholesterol (TC), low density lipoprotein (LDL), triglycerides (TG) and high density lipoprotein (HDL), Thiobarbituric acid reactive substances (TBARS) serum level, antioxidant enzymes activity (Superoxide dismutase: SOD; Glutathione peroxidase: GPx), hemoglobin (Hb) and Hb derivatives (oxyhemoglobin: HbO₂; carboxyhemoglobin: HbCO; sulfohemoglobin: SHb; met-hemoglobin: Met-Hb) were measured in control and high fat diet (HFD) rabbits. We found that the TC, LDL, TG and HDL (mg/dl) were significantly (p < 0.001) increased in HFD rabbits compared with control rabbits. A significant (p < 0.05) decrease in Hb (g/dl), percentage of hematocrit and RBCs count was observed in HFD rabbits compared with control rabbits while a significant increase in platelet and WBCs counts was observed. The TBARS was significantly (p < 0.05) increased in HFD rabbits compared with control rabbits while antioxidant enzymes SOD and GPx activity were significantly (p < 0.05) decreased. A significant increase in percentage of Met-Hb, HbCO and SHb was observed in HFD rabbits compared with control rabbits while a significant decrease in percentage of HbO₂ was observed. This study shows that hypercholesterolemia affects the level of Hb and Hb derivatives which causes anemia and may produce reactive oxygen species (ROSs) and other free radicals increasing TBARS and decreasing SOD and GPx enzymes activities. Hypercholesterolemia may promote the conversion of HbO ₂ and the fraction of unstable Hb molecules to Met-Hb, SHb and HbCO. Furthermore, increased platelet and WBCs count in HFD rabbits may be of pathophysiological importance for the progression of atherosclerosis and thromboembolic complications. This study suggests that hypercholesterolemia may produce free radicals which promote oxidation of Hb and reduce its concentration and conversion of HbO ₂ to Met-Hb and the fractions of unstable Hb molecules to Met-Hb, SHb and HbCO. Furthermore, an imbalance between free radical production and antioxidant enzymes activities may lead to oxidative stress.

Key words: High cholesterol diet, oxidative stress, antioxidant enzyme activates, red blood cells, atherosclerosis.

Advanced Journal of Microbiology Research Vol. 2016

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

© 2016 International Scholars Journals

Full Length Research Paper

Preliminary studies on Piliostigma thonningii Schum leaf extract: Phytochemical screening and in vitro antimalarial activity

A. Kwaji¹, P. U. Bassi², M. Aoill¹, C. M. Nneji³ and G. Ademowo³

¹Chemistry Department, Faculty of Science, University of Maiduguri, Borno State, Nigeria.

²Clinical Pharmacology Unit, Department Of Medicine, University of Maiduguri Teaching Hospital, Borno State, Nigeria.

³Institute for Medical Research and Training, College of Medicine, UCH, Ibadan, Oyo State, Nigeria.

Accepted 9 March, 2015

Abstract

Different parts of Piliostigma thonningii Scum (Caesalpinioideae) have been used medicinally. The roots and twigs have been used locally in the treatment of dysentery, fever, respiratory ailments, snake bites, hookworm and skin infections in Eastern Nigeria. The leaf extracts has been used for various ethnomedicinal purposes including the treatment of malaria all over Eastern Nigeria. In this study, we have investigated the inhibitory effects of the crude ethanol and methanol extracts for in vitro antimalarial activity against chloroquine resistant Plamodium Falciparum clone (W2-Indo-China isolates). The aqueous screening using reported methodologies for phytochemical screening and in vitro test methods, revealed the presence of alkaloids, tannins, saponnins, steroid, terponoids, flavonoids, cardiac glycosides and anthroquinoes. The crude leaf extracts obtained were tested for in vitro antimalarial activity using chloroquine resistant strain of P. Falciparum clone (W2 – Indochina isolates) . The 50% inhibitory concentrations (IC₅₀) were evaluated after 48 - 72 h contacts between the extracts and the parasite culture. The 50% inhibitory concentration values for both the crude amide ethanolic extract and the partially purified methanolic extract ranged between 6.20 - 15.06 µg/ml. While that of chloroquine was 0.316 µg/ml. This study suggested that P. thonningii leaf extract possess a significant level of antimalarial activity.

Key words: Pilostigma thonningii leaf, phytochemical screening, antimalarial activity.

Advanced Journal of Microbiology Research Vol. 2016

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

© 2016 International Scholars Journals

Full Length Research Paper

Determination of microbiological characteristics of Turkish Karin Kaymagi cheeses packaged in different materials

Salih Özdemir¹, Filiz Yangılar¹* and Cihat Ozdemir²

¹Department of Food Engineering, Agricultural Faculty, Ataturk University, Erzurum, Turkey.

²Department of Food Science, Oltu Vocational School, Atatürk University, Oltu, Erzurum, Turkey.

Accepted 26 March, 2015

Abstract

The aim of this study is to transport to dairy plants the making technique of Karin Kaymagi cheese and to make them hygienic cheese. Also, the effects of different packaging materials (artificial case, barrel and tripe) on microorganism counts in the cheese samples were determined. In this research, four different Karin Kaymagi cheese samples were prepared from white cheese, civil cheese, whey cheese, pasteurized cream and concentrated yoghurt mixes. These mixes were put in three different packaging materials (artificial case, barrel and tripe) and ripened at 12°C for 2, 15, 30 and 60 days. The means of total aerobic mesophilic (TAMB), lactic acid (LAB), coliforms, proteolytic, lipolytic, psychrotrophic, spore forming bacteria and yeast-moulds in the cheese samples were determined as 7.08, 6.11, 1.18, 5.13, 4.82, 5.30, 1.30 and 4.83 log cfu/g, respectively. As the LAB counts and the yeast-mould counts of samples increased, the coliform group bacteria counts decreased during ripening periods. The yeast-moulds counts of cheese samples packaged in barrel were lower than that of tripe and artificial case.

Key words: Karin Kaymagi cheese, microbiological characteristics, packaging materials.