MOSP - Macao Scientific Publishers

文章

Thermodynamics investigation of Ca2+ effect on Troponin-C (TnC): A QM/MM study

Mahmoud Raouf and Leila Mahdavian*

Abstract: Troponin (Tn) is an essential protein in calcium ion settings of skeletal and heart muscle contractions. It has three subcategories (TnC, TnI, TnT) which are connected to filament actin by tropomyosin. TnC controls the calcium in muscle contraction and is the Ca2+-binding subunit of the troponin complex. ATP facilitates separation of myosin from actin filament, eventually making thick filament to slip off thin filament. This results in short sarcomere. In this study, it is investigated that thermodynamics properties increase concentrations of Ca2+ and temperature present in lactic acid. Quantum mechanical and molecular dynamics methods were used to analyze the structure and stability of TnC-Ca2+ configuration. TnC-Ca2+ mutated active site in lactic acid and water solvent. Calcium ions approaching TnC caused twisting movement of TnC, so TnI-TnT eventually released the head of Myozin to actin. Increased lactic acid can increase calcium ion connection around TnC and decrease Ca to SR; increased temperature can increase metabolism and fatigue of skeletal muscles, emptying glycolysis and reducing muscle activity.[...] Read More.

Keywords: Troponin C (TnC), calcium ion (Ca2+), lactic acid, fatigue of skeletal muscles, QM/MM.

Full text

Download：934

文章

Isolation and characterization of high caffeine-tolerant bacterium strains from the soil of tea garden

Fang-Yuan Fan, Yan Xu, Yue-Rong Liang, Xin-Qiang Zheng, Devajit Borthakur, and Jian-Liang Lu*

Abstract: Microbial biodegradation is an important and promising decaffeination approach because of its low cost and high security. The efficiency of this approach mainly depends on the characteristics of the strain. Twenty bacterium strains were isolated from soil of tea garden and exhibited high caffeine-tolerance, and these strains could grow on the medium supplemented with 20 g L-1 caffeine as the sole source for nitrogen and carbon. According to the physiological-biochemical characteristics and 16S rRNA gene sequence blast, two of them (CT25 and CT75) were identified as Pseudomonas putida. The results also showed that caffeine was not the preferential nutrition source for growth of strain CT25, and high level caffeine inhibited the bacterium amplification although caffeine could be metabolized by this strain. The CT25 grew well in agitated liquid medium when the incubation temperature was around 30°C. High initial concentration of strain inoculums would improve the efficiency of caffeine degradation.[...] Read More.

Keywords: Caffeine-tolerant bacterium, identification, 16S rRNA gene, caffeine biodegradation, growth condition.

Full text

Download：983

文章

Contamination of cattle carcasses by Escherichia coli shiga like toxin with high antimicrobials resistance

Everlon Cid Rigobelo*, Renato Pariz Maluta, Clarissa Araújo Borges, Lívia Gerbasi Beraldo, Manoel Victor Franco, Lemos Sirlei Aparecida Maestá and Fernando Antonio de Ávila

Abstract: During processing of cattle carcasses, contamination may occurs with the transfer of microbiota of animals feaces to carcasses. This contamination many times may be by Escherichia coli carriers of virulence factor as stx and eae genes being classified as Shiga like toxin. Shiga toxin-producing Escherichia coli (STEC) is recognized wordwide as human pathogen. A survey was performed to determine the sensibility profile to several antimicrobial drugs of STEC in carcasses obtained from an abattoir in Brazil between March 2008 and August at 2009. A total of 120 STEC were isolated. All isolates were confirmed as being E. coli by their biochemical analysis and submitted to polymerase chain reaction (PCR) for detection of stx, eae and ehly genes. No strains was isolated being carriers of ehly gene. The number of isolates carriers of eae gene were 48/120. The most frequent resistance was seen against cephalothin (84.0%), streptomycin (45.0%), nalidixic acid (42.0%) and tetracycline (20.0%). Multidrug resistance (MDR) to three or more antimicrobial agents was observed in 46 (38.3%) E. coli isolates. The findings of STEC and MRD show that cattle carcasses may be a reservoir of pathogenic bacterial for the consumer public.[...] Read More.

Keywords: Multi-drug resistance, Escherichia coli, shiga toxin-producing Escherichia coli (STEC).

Full text

Download：891

文章

Mycobacterium tuberculosis TLR2 agonists LprA, LM and Man-LAM induce notch1 and socs3 transcription

Erika Nahomy Marino-Marmolejo, Citlalli Tornez-Benítez, Vania Elvira Bonifaz-Peña, Mabel Guzmán-Rodríguez, Hugo Enrique López-González, Abel Gutiérrez-Ortega, Leticia Santos* and Mario Alberto Flores-Valdez*

Abstract: Mycobacterium tuberculosis employs a number of strategies to subvert host signaling events, leading to its persistence within macrophages. Upon infection, Mycobacterium bovis BCG induce the expression of suppressor of cytokine signaling 3 (socs3), in a Toll-like receptor 2 (TLR2)-Notch1-dependent manner. Purified phosphatidyl inositol di-mannosides (a TLR2 agonist) act as an inducer for the Notch1-socs3 pathway. This prompted us to analyze other TLR2 agonists seeking for additional molecules that may affect this pathway. We found that lipoprotein LprA, as well as glycolipids lipomannan (LM), and mannose- capped lipoarabinomannan (ManLAM) treatment of murine macrophages resulted in stimulation of notch1 and socs3 transcription.[...] Read More.

Keywords: Mycobacterium tuberculosis, Toll-like receptor 2 (TLR2), notch1, socs3, innate immunity.

Full text

Download：937

文章

An investigation on antibiotic resistance of Neisseria gonorrhoeae isolated from gonorrheal patients in Zahedan, Iran from 2007 to 2010

Mohammad Bokaeian, Mazhar Iqbal Qureshi, Soroush Dabiri and Amir Hossein Mohagheghi Fard*

Abstract: Present study was aimed to determine antibiotic susceptibility and penicillinase production by Neisseria gonorrhoeae strains isolated from gonorrheal patients in Zahedan (south-east Iran). In a descriptive study from 2007 to 2010, 400 suspected patients were studied by history review, medical examination, Gram staining and culture in Thayer-Martin medium. Antibiotic susceptibility test of isolated strains was done by disk diffusion method and penicillinase test in penicillin resistant isolates by aciodometric method. The culture of 77(19.2%) of gonorrheal patients were positive. The resistance rate against applied antibiotics was as follow: penicillin (79.2%), ciprofloxacin (53.2%), ceftriaxone (3.8%), spectinomycin (2.5%), cefixim (12.9%), co-trimoxazole (93.5%), tetracycline (88.3%) and gentamicin (29.8%). In the meantime, 83.1% of penicillin resistant isolates produced penicillinase enzyme. Ceftriaxone, spectinomycin and cefixime are the sole antibiotics that could be considered as selective drugs. Quinolones which were regarded as an effective group of antibiotics until recently, haven lost their efficacy. Resistance against other antibiotics is rapidly growing, thus, conducting experimental tests and determination of minimum inhibitory concentration and clinical trial studies at fixed intervals can contribute to diagnosis of resistance of gonococci and rapid and successful treatment of their infections.[...] Read More.

Keywords: Neisseria gonorrhoeae, gonorrhea, penicillinase (β-lactamase).

Full text

Download：881

文章

Cytokine genes expression in mice hepatocytes during malaria infection

Saad Alkahtani*, AL-Farraj S. A., Saud A. Alarifi, AL-Eissa Mohammed saad and Al-Dahmash B.

Abstract: The aim of this study was to investigate the inflammation genes (IL-1 , IL-6, TNF - and iNos) responses to Plasmodium chabaudi malaria in the liver of female C57BL/6 hepatocytes via mRNA expression due to infection with P. chabaudi at different time points. Mice were injected intraperitoneally (ip) with 106 P. chabaudi-infected erythrocytes and then scarified at days (0, 1, 4 and 8 respectively). RT-PCR was used to quantify liver inflammation genes. The levels of IL-1 , IL- 6 and TNF were significantly increased at days 1 and 8. The total iNos were significantly increased at all days after infection. In conclusion, present data has shown that infection with P. chabaudi stimulated infalammation genes in the liver. Thus, we suggest the implication of oxidative stress due to outcome of malaria in mice hepatocytes according to its natural function need to be confirmed with a larger number of samples to be used as a reliable inflammation detection method.[...] Read More.

Keywords: Inflammation, malaria, mice, liver.

Full text

Download：895

文章

The mRNA quantitative analysis, prokaryotic expression and structure prediction of hepatocarcinogenesis related gene idh3 under AFB1 stress

Full Length Research Paper

Abstract: By differential proteomics analysis, it was found that the expression level of IDH3 (Isocitrate dehydrogenase 3 ) in mouse liver was significantly increased under the stress of Aflatoxin B1. To validate the result of differential proteomics analysis, fluorescence quantitative PCR was used to detect the changing trend of idh3 mRNA volume induced by Aflatoxin B1 in mouse liver. The result showed that the expression volume of idh3 mRNA showed an increasing trend with the increase of Aflatoxin B1 concentration, which corresponded with the result of differential proteomics analysis. The protokaryon expression vector for idh3 was constructed in the study with pET28a as a recipient plasmid. The expression vector (pET28a-idh3 ) was used to transform BL21, after which the positive expression strain (Escherichia coli BL21/pET28a-idh3 ) was induced to express with 100 mmol/L IPTG under 28°C for 4 h, and the prokaryotic expression product of IDH3 was successfully detected by SDS-PAGE electrophoresis. The molecule structure of IDH3 was predicted by bioinformatics analysis, and the results showed that the total number of negatively and positively charged residues were 42 and 39, respectively. Five hydrohpobic domains were predicted in the protein, and its average hydrophobicity was -0.069. There was 43% - helix and 20% -pleated sheet in the molecule, and the tertiary structure of IDH3 was constituted by 12 - helices and 12 -pleated sheets. Based on the results of bioinformatics analysis, the fragments of 1- 17 and 112-123 residues of IDH3 were selected as candidates for further effective polyclonal antibody preparation. The results of this study paved way for further exploration of the role of idh3 in the process of liver carceration induced by Aflatoxin B1.[...] Read More.

Keywords: IDH3 , aflatoxin B1, liver, canceration, bioinformatics analysis.

Full text

Download：1396

文章

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

Full Length Research Paper

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.

Full text

Download：944

文章

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.

Full text

Download：996

文章

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.

Full text

Download：1016

Search Filter