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81.
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a zoonotic pathogen that causes food-borne disease in humans ranging from watery diarrhea to bloody diarrhea and severe hemorrhagic colitis, renal failure and hemolytic uremic syndrome. Cattle, the most important source of E. coli O157:H7 transmission to humans, harbor the bacteria in their gastrointestinal tract without showing clinical symptoms. Prevention of E. coli O157:H7 infections in ruminants could diminish the public health risk. However, there is no specific treatment available nor a vaccine or a therapeutic agent which completely prevents E. coli O157:H7 infections in cattle. This paper provides an overview of latest research data on eradicating enterohemorrhagic E. coli O157:H7 in ruminants by use of bovine lactoferrin administration. The article provides insights into the anti-microbial and immunomodulatory activities of bovine lactoferrin against E. coli O157:H7 infections in cattle.  相似文献   
82.
Calcium bodies are internal epithelial sacs found in terrestrial isopods of the family Trichoniscidae that contain a mineralized extracellular matrix that is deposited and resorbed in relation to the molt cycle. Calcium bodies in several trichoniscids are filled with bacteria, the function of which is currently unknown. The woodlouse Hyloniscus riparius differs from other trichoniscids in that it possesses two different pairs of calcium bodies, the posterior pair being filled with bacteria and the anterior pair being devoid of bacteria. We explored the development of these organs and bacterial colonization of their lumen during the postmarsupial development with the use of optical clearing and whole-body confocal imaging of larval and juvenile stages. Our results show that calcium bodies are formed as invaginations of the epidermis in the region of intersegmental membranes during the postmarsupial development. The anterior pair of calcium bodies is generated during the first postmarsupial manca stage, whereas the posterior calcium bodies first appear in juveniles and are immediately colonized by bacteria, likely through a connection between the calcium body lumen and the body surface. Mineral is deposited in calcium bodies as soon as they are present.  相似文献   
83.
    
Phage display is a technique in which a foreign protein or peptide is presented at the surface of a (filamentous) bacteriophage. This system, developed by Smith [(1985), Science 228, 1315–1317], was originally used to create large libraries of antibodies for the purpose of selecting those that strongly bound a particular antigen. More recently it was also employed to present peptides, domains of proteins, or intact proteins at the surface of phages, again to identify high-affinity interactions with ligands. Here we want to illustrate the use of phage display, in combination with PCR saturation mutagenesis, for the study of protein–protein interactions. Rather than selecting for mutants having high affinity, we systematically investigate the binding of every variant with its natural ligand. Via a modified ELISA we can calculate a relative affinity. As a model system we chose to display thymosin 4 on the phage surface in order to study its interaction with actin.  相似文献   
84.
Earthworms are segmented invertebrates that belong to the phylum Annelida. The segments can be divided into the anterior, clitellar and posterior parts. If the anterior part of the earthworm, which includes the brain, is amputated, the worm would essentially survive even in the absence of the brain. In these brain amputee-derived worms, the nerve cord serves as the primary control center for neurological function. In this current work, we studied changes in the expression levels of anti-acetylated tubulin and serotonin as the indicators of neuro-regenerative processes. The data reveal that the blastemal tissues express the acetylated tubulin and serotonin from day four and that the worm amputated at the 7th segment takes 30 days to complete the regeneration of brain. The ability of self-assemblage is one of the specific functions of the earthworm’s brain. The brain amputee restored the ability of self-assemblage on the eighth day.  相似文献   
85.
The activity of platelet monoamine oxidase was found to be significantly lower in normal female subjects who smoked at least 5 cigarettes per day than in non-smokers. The platelet MAO activity of individuals who had given up smoking was not significantly different from the activity for non-smokers. The difference in activities between smokers and non-smokers, due entirely to a Vmax rather than a Km change, was not due to a direct effect of nicotine upon the platelet MAO. In addition, platelet-poor plasma from smokers activated platelet MAO in an identical manner to that from non-smokers. The significance of these results are discussed in terms of personality characteristics such as impulsivity and sensation seeking, that may be related to both smoking and to low MAO activity.  相似文献   
86.
The stain is applied routinely to tissues fixed in 10% buffered formalin (pH near 7.0) or in Bouin's fluid. Bring paraffin section to water as usual and mordant 72 hr in 5% CrCl3 dissolved in 5% acetic acid. Wash in water and in 70% alcohol and stain 6 hr. Formula of staining solution: new fuchsin, 1% in 70% alcohol, 100 ml; HCl, conc., 2 ml and paraldehyde, 2 ml, mixed together and added to the dye solution; let stand 24 hr before use. After staining, wash in running tap water 5-10 min, rinse in distilled water and counterstain if desired. Dehydration in alcohol, clearing and covering completes the process. When the paraldehyde is obtained from a freshly opened bottle, standardized staining times can be used and thus eliminate the necessity of differentiating individual slides. The granules of beta cells stained deep blue to purple and were demonstrated in the pancreatic islet of man, dog, mouse, frog, guinea pig and rabbit.  相似文献   
87.
88.
The NTFB genes from two major histocomptibility complex (MHC) ancestral haplotypes have been compared. The genes carried by the ancestral haplotypes 8.1 (A1,B8,BfS,C4AQ0, C4B1,DR3) and 57.1 (A1,B57, BfS,C4A6,C4B1,DR7) were cloned and sequenced to determine the degree of polymorphism. In this report we show that the r e spective TNF genes are allelic and have unique nucleotide sequences. The data demonstrate the presence of three nucleotide differences between the TNFB alleles of 8.1 and 57.1. Two of the differences occur in untranslated regions of the gene but the third nucleotide change results in amino acid differences in the mature TNFB protein. These polymorphisms may have implications with respect to differential regulation in disease-and nondisease-associated haplotypes.The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession number M55913.  相似文献   
89.
In this work, the most detrimental missense mutations of aspartoacylase that cause Canavan??s disease were identified computationally and the substrate binding efficiencies of those missense mutations were analyzed. Out of 30 missense mutations, I-Mutant 2.0, SIFT and PolyPhen programs identified 22 variants that were less stable, deleterious and damaging respectively. Subsequently, modeling of these 22 variants was performed to understand the change in their conformations with respect to the native aspartoacylase by computing their root mean squared deviation (RMSD). Furthermore, the native protein and the 22 mutants were docked with the substrate NAA (N-Acetyl-Aspartic acid) to explain the substrate binding efficiencies of those detrimental missense mutations. Among the 22 mutants, the docking studies identified that 15 mutants caused lower binding affinity for NAA than the native protein. Finally, normal mode analysis determined that the loss of binding affinity of these 15 mutants was caused by altered flexibility in the amino acids that bind to NAA compared with the native protein. Thus, the present study showed that the majority of the substrate-binding amino acids in those 15 mutants displayed loss of flexibility, which could be the theoretical explanation of decreased binding affinity between the mutant aspartoacylases and NAA.  相似文献   
90.
A selective, accurate, precise and reproducible high-performance liquid chromatographic assay was developed for the quantitation of irbesartan, an angiotensin II antagonist, in human plasma and urine samples. The method involved solid-phase extraction of irbesartan and internal standard (I.S.) using a 100-mg Isolute CN cartridge. A portion of the eluate was injected onto an ODS analytical column connected to a fluorescence detector that was set at an excitation wavelength of 250 nm and an emission wavelength of 371 nm. The mobile phase consisted of 50% acetonitrile and a 50% weak phosphate-triethylamine solution, pH 3.5, at a flow-rate of 0.8 ml/min. The assay was linear from 1 to 1000 ng/ml with both plasma and urine. In either matrix, the lower limit of quantitation was 1 ng/ml. The analyses of quality control samples indicated that the nominal values could be predicted with an accuracy >95%. The inter- and intra-day coefficients of variation for the analyses in both matrices were <8%. Irbesartan was stable in both human plasma and urine for at least seven months at −20°C. The application of the assay to a pharmacokinetic study is described.  相似文献   
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