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21.
Michael Francis Dutton Mulunda Mwanza Suretha de Kock Lishia Daya Khilosia 《Mycotoxin Research》2012,28(1):17-23
The contamination of cow’s milk at the farm level with aflatoxin M1 was investigated in South Africa. Samples of feeds, forage, maize and milk were taken at nine dairy farms, and at the same
time samples of the processed milk (retail milk) were collected from the respective dairies to which the farms delivered their
milk. The feeds were analysed for aflatoxin B1 and the milk samples for aflatoxin M1 using high performance liquid chromatography (HPLC) and fluorescence detection. All milk samples from the dairy farms were
positive for aflatoxin M1, ranging from 0.02 μg/l to 1.5 μg/l. Retail milk was also frequently contaminated with AFM1, at levels of 0.01-3.1 μg/l. High AFB1 levels in feed materials on the farms supplying the raw milk indicate that various sources account for this contamination
frequency in milk. 相似文献
22.
Transport of fertilised and unfertilized ova was studied in 22 crossbred (Landrace x Yorkshire) multiparous sows. Sows in the inseminated group (I-group, n=11) were inseminated once with 100ml of BTS extended semen from two fertile boars with a total of 10 x 10 (9) spermatozoa during the second oestrus after weaning between 18 and 8h prior to estimated time of ovulation, as estimated from the first oestrus after weaning. All the sows were slaughtered between 36 and 48 h after ovulation in the second oestrus after weaning by stunning and bleeding. After slaughter, the reproductive tract was immediately recovered, the isthmus was divided into three equal segments, and the number of ova was determined in each segment and in the upper third of the uterine horn from the UTJ. There were no significant differences (P>0.05) either in the intervals from ovulation to slaughter (42.3+/-6.2h versus 43.2+/-5.4h) or in the numbers of corpora lutea (CL) (18.2+/-5.5 versus 15.9+/-3.5) between the non-inseminated (N-group) and the inseminated groups (I-group), respectively. Ova recovery rate was 92.5% in the N-group and 82.9% in the I-group (P>0.05). In the I-group, ova had passed 2.2+/-0.3 segments whereas in the N-group, ova had passed 2.6+/-0.3 segments (P=0.38). It can be concluded that there is no difference in the transportation of either fertilised or unfertilized ova in the reproductive tract of pigs. 相似文献
23.
This study was designed to characterize changes in the motility of the oviductal isthmus in relation to endocrine changes around ovulation in unrestrained sows in their normal environment. Oviductal isthmic motility was monitored on Polyview from 11 h prior to and up to 36 h after ovulation in 13 unrestrained multiparous sows during their second estrus after weaning, using a pressure microtransducer implanted 3 cm into the isthmus. Both the maximum, minimum and mean pressures and the frequency of phasic pressure fluctuations were high prior to ovulation but declined significantly (P<0.05) at 9 to 12 h, 13 to 16 h, 13 to 16 h and 5 to 8 h after ovulation, respectively. Plasma estradiol-17beta and prostaglandin F2alpha metabolite levels declined significantly (P<0.05) at 4 to 7 h prior to ovulation while progesterone levels increased significantly (P<0.01) at 5 to 8 h after ovulation. The decrease in the plasma estradiol-17beta levels was correlated to the decrease in maximum and mean pressures and the frequency of phasic pressure fluctuations (n=113; r=0.30, 0.25, 0.25, respectively; P<0.01) but not to the decrease in minimum pressure (n=113; r=0.17, P>0.05). Similarly, the decrease in PGF2alpha metabolite levels was correlated to the decrease in minimum, maximum and mean pressures and the frequency of phasic pressure fluctuations (n=112; r=0.43, 0.35, 0.38, 0.32, respectively; P<0.001). Conversely, the increase in plasma progesterone levels was correlated to the decrease in minimum, maximum and mean pressures and the frequency of phasic pressure fluctuations (n=113; r=-0.56, -0.70, -0.68, -0.60, respectively; P<0.001). Therefore, the pressure parameters seem to be influenced by changes in the levels of estradiol-17beta, prostaglandin F2alpha and progesterone with respect to ovulation. 相似文献
24.
Essentiality of a Newly Identified Carbohydrate-Binding Module for the Function of CelB (BH0603) from the Alkaliphilic Bacterium Bacillus halodurans 下载免费PDF全文
Benson Munyali Wamalwa Makiko Sakka Paul Mwanza Shiundu Kunio Ohmiya Tetsuya Kimura Kazuo Sakka 《Applied microbiology》2006,72(10):6851-6853
CelB (BH0603) from Bacillus halodurans is a modular glycoside hydrolase with a family 5 catalytic module, an immunoglobulin-like module, and module PfamB of unknown function. The recombinant PfamB module bound to Avicel and was essential for CelB hydrolytic function. We propose that module PfamB be designated a new carbohydrate-binding module. 相似文献
25.
We compared day-journey length and daily diets of solitary male gorillas in lowland versus highland habitats. Solitary males
in tropical forests of Zaire tend to travel longer distances, to visit more types of vegetation, and to consume more kinds
of food than a solitary male mountain gorilla in the Virunga Volcanoes did. The number of feeding sites per day is larger
and the mean distance between feeding sites is far longer for the former than the latter. These observations may reflect differences
in food breadth and availability between highland and lowland habitats. The herbaceous plants that are eaten by mountain gorillas
are densely and evenly distributed in the higher montane forest of the Virungas, where gorillas need not cover long distances
to search for food. In contrast, herbaceous plants are scarce in primary and ancient secondary forests of lowland habitats,
where gorillas travel long distances and eat various fruits and insects. The patchy and unpredictable distribution of foods
may extend the distances over which gorillas search for food in the lowland habitat. However, solitary males showed a prominent
reduction in day-journey length and changed their choices of food during the nonfruiting season (the long rainy and dry seasons)
in the lowland habitats. This strategy may have developed during the Pleistocene and may have enabled them to enlarge their
ranges to the higher montane forests, where fruits are sparse throughout the year. 相似文献
26.
27.
Razdan P Mwanza AM Kindahl H Rodriguez-Martinez H Hultén F Einarsson S 《Animal reproduction science》2002,70(1-2):127-137
This study was conducted to evaluate the effect of adrenal stimulation by synthetic adrenocorticotrophic hormone (ACTH) on the first 2 days of pregnancy in 22 multiparous sows. The experiment was performed during the second oestrus after weaning and the sows were divided into one control (C-group) and one experiment group (E-group). To determine the time of ovulation, transrectal ultrasonographic examination was performed. E-group sows were treated repeatedly with 0.1 mg/kg bodyweight of synthetic ACTH (tetracosactide) i.v. 4-8h after ovulation and continuing every 6h, until slaughter. Blood samples were collected every second hour from about 12h before expected ovulation until slaughter and were analyzed for cortisol, prostaglandin F(2 alpha) -metabolite, and progesterone (P(4)). All sows were slaughtered approximately 48 h after ovulation and the isthmic part of the oviduct was divided into three equally long segments and flushed separately with phosphate buffered saline (PBS). The uterine horns were also flushed with PBS. The embryos of the E-group sows tended (P=0.056) to have a lower cleavage rate than the embryos of the C-group sows but there was no difference between groups in oviductal transport rate of the embryos. In the E-group, significantly (P<0.05) more sows had only embryos with <20 spermatozoa attached to the ZP compared with the C-group. The plasma concentration of cortisol was significantly higher (P<0.0001) in the E-group sows during the time of treatment while the baseline level of prostaglandin F(2 alpha) -metabolite was significantly lower. The baseline level of progesterone increased in both groups after ovulation but there was no significant difference between the groups. Repeated ACTH-stimulation (1) had no effect on the oviductal transport rate of the embryos, (2) had a negative effect on the embryo development, (3) and caused a changed endocrine profile that might have changed oviductal milieu affecting embryo development. 相似文献
28.
O.M. Makinde M.C. Adetunji O.T. Ezeokoli B.T. Odumosu L. Ngoma M. Mwanza C.N. Ezekiel 《Letters in applied microbiology》2021,72(2):187-195
Contamination of ready-to-eat (RTE) foods by pathogenic bacteria may predispose consumers to foodborne diseases. This study investigated the presence of bacterial contaminants and their antibiotic susceptibility patterns in three locally processed RTE foods (eko, fufu and zobo) vended in urban markets in Ogun state, Nigeria. Bacteria isolated from a total of 120 RTE food samples were identified by 16S rRNA gene phylogeny while susceptibility patterns to eight classes of antibiotics were determined by the disc diffusion method. Species belonging to the genera Acinetobacter and Enterobacter were recovered from all RTE food types investigated, Klebsiella and Staphylococcus were recovered from eko and fufu samples, while those of Shigella were recovered from eko samples. Enterobacter hormaechei was the most prevalent species in all three RTE food types. Precisely 99% of 149 isolates were multidrug-resistant, suggesting a high risk for RTE food handlers and consumers. Co-resistance to ampicillin and cephalothin was the most frequently observed resistance phenotype. Results demonstrate that improved hygiene practices by food processors and vendors are urgently required during RTE processing and retail. Also, adequate food safety guidelines, regulation and enforcement by relevant government agencies are needed to improve the safety of RTE foods and ensure the protection of consumer health. 相似文献
29.
Wamalwa BM Zhao G Sakka M Shiundu PM Kimura T Sakka K 《Bioscience, biotechnology, and biochemistry》2007,71(3):688-693
The putative xyn11A structural gene (BH0899) encoding a family-11 xylanase from alkaliphilic Bacillus halodurans strain C-125 was heterologously expressed in the yeast Kluyveromyces lactis CBS 1065 and secreted to a level of 156 microg/ml under selective culture conditions in shake flasks. The Xyn11A production level in shake flask cultures of K. lactis CBS 1065 was higher than that reported for other xylanase genes placed under the control of the regulated LAC4 promoter on a plasmid containing an entire sequence of pKD1 from Kluyveromyces drosophilarium. Recombinant Xyn11A was highly active over pH range from 3 to 10, with maximal activity around pH 7. The enzyme showed a specific activity of 628 U/mg-protein on birchwood xylan as substrate, but no cellulase or beta-xylosidase activity. 相似文献
30.
Mulunda Mwanza Lazlow Kametler Alex Bonai Veronika Rajli Melinda Kovacs Michael Francis Dutton 《Mycotoxin Research》2009,25(4):233-238
Lymphocytes cell obtained from healthy human donors and pigs were exposed to fumonisin B1 (FB1) and ochratoxin A (OTA), which have been found to be immunosuppressive, carcinogenic and mutagenic, to ascertain their single
and combined cytotoxic effects with time and to assess the suitability of animal lymphocytes as test agents in comparison
to human cells. The main objectives of this work were to assess the use of animal lymphocytes, particularly pig lymphocytes,
for their use in the Methyl Thiazol Tetrazolium (MTT) cytotoxicity test, making them more accessible to animal research-based
institutes in comparison to human lymphocytes previously used, and to study the cytotoxic and synergism or antagonistic effects
of FB1 and OTA. The MTT assay, which measures cell viability and proliferation based on reduction of MTT to a blue dye, also
used the addition of phytohaemagglutinin (PHA) to stimulate the blood cells. The results showed a progressive decrease in
lymphocytes viability with time of exposure to the toxins. It was also noted that FB1, as compared to OTA, had a lower cytotoxicity
on both human and pig lymphocytes cells. In addition, when the two mycotoxins were combined, a synergistic decrease of cell
viability in both human and pig lymphocytes was observed, with pig lymphocytes showing a greater sensitivity. This study has
shown that the MTT assay can be used for the determination of cytotoxicity of mycotoxins using animal, and in particular pig,
lymphocytes, which eliminates the use of human donors and other cell cultures. 相似文献