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文章
G. I. Okwu, Premila N. Achar* and Santosh K. Sharma
Abstract: A total of 150 ready to use food thickeners were randomly collected from various markets in both urban and rural settings. Four of the samples tested Achi (Brachystegia eurycoma), Akpalata ( Afzelia africana), Ofor (Detarium microcarpum), and Ukpo (Mucuna flagellipes) were contaminated with fungal flora. The most common and prevalent fungi observed on incubated powdered form of food thickeners on media, were the Aspergillus group namely Aspergillus flavus, Aspergillus parasiticus and Aspergillus niger. Pure isolates of A. flavus and A. parasiticus from various food thickeners from open markets in Nigeria were screened for their potential to produce aflatoxin B1 (AFB 1) on agar media. Ultraviolet (UV) light, a standard procedure was used to differentiate the toxin from non-toxin form of Aspergillus species. Further, aflatoxin quantification was done using thin layer chromatography (TLC) followed by fluorometry. A. flavus was more prevalent than A. parasiticus in all samples. Toxin and non-toxin isolates were grouped as per bright greenish-yellow fluorescence (BGYF) presumptive test under UV light. The amounts of AFB1 from A. flavus isolates ranged between 0.94 to 3.83 µg/g of agar and all positive A. parasiticus ranged from 0.22 - 2.87 µg/g of agar. Analysis of food thickeners also revealed a high incidence and alarming levels of naturally produced aflatoxin. The levels of AFB1 ranged between 4.0 and 95 µg/g in various food thickeners tested. That the presence of aflatoxin in food thickeners poses a potential health threat to consumers in this part of Nigeria and elsewhere is discussed.[...] Read More.
Keywords: Ready-to-use food thickeners, Aspergillus sp., aflatoxin B1, thin layer chromatography, fluorometry.
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文章
Hu Yushan, Luo Lei, Liu Weijia, and Chen Xiaoguang*
Abstract: This study aims to develop a rapid method for identifying pathogenic bacteria based on the sequence difference of pathogenic bacteria groEL gene. A pair of universal degenerate primers was designed to amplify the groEL genes of 34 major species of 16 genus’s of pathogenic bacteria. The conservation, variation and the interspecies phylogenetic relations of the groEL gene sequences were informatically analysed. Our results showed that the groEL gene fragments of the selected pathogenic bacteria could be amplified using the degenerate primer. The results of the sequence comparative study indicated that the groEL gene is characterized by conservation and variation, while the variation regions are distributed separately among the conserved regions, just like the mosaic. This conservation and variation coexistence of pathogenic bacteria groEL genes could provide a solid basis for the rapid identification of pathogenic bacteria and the development of a diagnostic microarray.[...] Read More.
Keywords: groEL, homology, phylogenesis.
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文章
Liang Renjie*, Shi Shidi and Sun Changsen
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.[...] Read More.
Keywords: Glycyrrhiza glabra polysaccharides, rat, TGF- 1 mRNA, aspartate aminotransferase (AST), carbon tetrachloride.
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文章
Y. M. Somorin* and S. A. Bankole
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.[...] Read More.
Keywords: Fungi, contaminants, Ofada, Abakaliki, rice, mycotoxin, mycoflora.
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E. A. Ophori* and E. C. Wemabu
Abstract: The study was aimed at determining the bacterial agents of the upper respiratory tract infection (URTI) and the susceptibility of isolates to propolis. Propolis extract was obtained by 70% ethanol and serial dilutions of 0.25, 0.5, 1, 2, 4, 8 and 10 µg/ml prepared. A total of 250 throat swabs were obtained from patients (age between 15 - 30 years) which were diagnosed with upper respiratory tract infection attending the central hospital, Benin City. Samples were collected between February and December, 2008 from 142 (56.8%) males and 108 (43.2%) females, inoculated on blood agar, eosin methylene blue agar and chocolate agar and incubated at 37°C for 24 - 48 h aerobically except for chocolate agar which was incubated microaerophically. The isolates were characterized by standard microbiological procedures. Of the 250 samples, 160 (64%) had positive cultures with Haemophilus influenzae having the highest prevalence (20.8%), followed by Klebsiella pneumoniae (19.2%), Streptococcus pneumoniae (12.0%), Moraxella catarrhalis (10%), Streptococcus pyogenes (2%). The highest rate of isolates was from the age group of 15 - 18 years (91). This was significantly higher than other groups p > 0.05. M. catarrhalis and S. pyogenes were not isolated in age group 23 – 26. propolis antimicrobial activity revealed that all isolates were sensitive to propolis at all concentrations with K. pneumoniae and S. pneumonia having zones of inhibition of 32 and 30 mm respectively. The findings suggest that propolis is a very effective antimicrobial agent for the treatment and management of URTI caused by bacterial species.[...] Read More.
Keywords: Upper respiratory tract infection, minimum inhibitory concentration, propolis, bacteria, antimicrobial activity.
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文章
Naoual Jamaly, Abdelaziz Benjouad, Roberta Comunian, Elisabetta Daga and Mohammed Bouksaim*
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.[...] Read More.
Keywords: Enterococcus durans, Moroccan dairy products, species-specific PCR (Polymerase chain reaction), biochemical properties, adjunct starter cultures.
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文章
Lan Liu*, Xuesong Peng, Lijuan Chu, Qian Liu, Juan Xiong, Chunmei Jing, Yongwu Xia and Yu Shi
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.[...] Read More.
Keywords: Living donor liver transplantation, risk factor, children.
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文章
S. A. A. Al-Rashed, F. D. A. Bakar, M. Said, O. Hassan, A. Rabu, R. M. Illias and A. M. A. Murad*
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.[...] Read More.
Keywords: Endochitinase, Trichoderma virens, recombinant, characterization.
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文章
S. E. Baidoo, S. C. K. Tay and H. H. Abruquah*
Abstract: Intestinal helminths are among the most common and widespread of human infections, contributing to poor nutritional status, anaemia and impaired growth. Anaemia and iron deficiency in pregnancy is a major public health problem in developing countries, but their causes are not always known. The objective of this study was to assess the prevalence and severity of anaemia and iron deficiency and their association with helminths, among pregnant women in the Ashanti region of Ghana. A cohort study was carried out in the Sekyere east district of the Ashanti region of Ghana. 108 pregnant women were followed until 5-10 weeks postpartum, during the period of December 2005 - November 2006. Haemoglobin and total serum iron concentrations were evaluated in venous blood samples and helminths infections were evaluated in stool samples in each trimester using standard methods. Of the 108 pregnant women, 54.9% were found to be anaemic. The highest prevalence of anaemia and low iron stores (57.4 and 32.4%, respectively) were found in the second trimester. Only 17.6% had evidence of helminths infection, with Necator americanus (hookworm) being the commonest (13.9%). There was a significant association between hookworm infection and low iron stores. The study concluded that hookworm infection is a strong predictor of iron status. These findings reinforce the need to provide anthelminthic therapy to infected women before conception as public health strategy in reducing the prevalence of hookworm infection in addition to providing nutritional and iron supplements to effectively control anaemia in pregnancy.[...] Read More.
Keywords: Intestinal helminth, anaemia, paragravids, primigravids.
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文章
Maras Meltem*, Akman Yildiz, Yula Erkan and Gökmen Tülin
Abstract: In response to osmotic stress, gram positive bacteria Streptococcus agalactiae and enterobacteria Escherichia coli accumulates compatible solutes from the medium, stress response systems may enable bacteria to adapt cellular response and survival systems to a variety of stress conditions. S. agalactiae and E. coli strains have a transporter for carnitine that can respond to osmotic stress by regulating its own activity. Brain heart infusion (BHI) broth medium with 1 mM L-carnitine was the medium with the highest growth to be observed. The growth of the E. coli strain was faster than the growth of S. agalactiae strain. S. agalactiae and E. coli are known as bacteria being hard to grow at the laboratory tests for making clinical diagnosis. The medium with L-carnitine factor used in laboratory tests accelerates the bacterial growth.[...] Read More.
Keywords: Bacterial growth, carnitine, osmoprotectant, Streptococcus agalactiae, Escherichia coli.
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