Intracytoplasmic sperm injection without polyvinylpyrrolidone: an essential precaution?
Explore the source record for details and available documents.
Cytoplasm↗
Biomedical subjects
B Ray
Publications and source records attributed to B Ray.
The indirect immunobead test for seminal antisperm antibodies and fertilization rates at in-vitro fertilization.
A series of 183 patients with positive indirect immunobead tests on semen was studied to determine the correlation in semen between specific antibody types, binding sites, antibody concentration, and fertilizing ability. IgM was present in only 44 ejaculates and was present in sufficient quantity to cause significant binding to immunobeads (i.e. >20% of motile donor spermatozoa) in only three of them. There was no correlation between the percentages of motile donor spermatozoa that bound IgA and IgG immunobeads but the two classes of beads generally bound to the same region of the spermatozoa. A total of 63 couples went on to attempt in-vitro fertilization (IVF) treatment, all with mature eggs recovered. Of these mature eggs, 44% were fertilized and cleaved normally in comparison to 68% in a group of patients with tubal disease. Fertilization rates in individuals followed a bimodal distribution with a substantial number of couples experiencing zero or very poor rates (0-20%), the mode for the remainder lying between 60 and 80%. The fertilization rate tended to decrease as the amount of antibody increased. The percentage of donor spermatozoa that bound to immunobeads, taken as the greater of IgA and IgG, was selected by logistic regression as a significant predictor of poor fertilization (rate <=25%). The predictive power of the equation was improved by including the motile normal sperm concentration but the equation could only account for a small proportion of the total variation in fertilization rate. The presence of antibodies to the sperm head was highly correlated with the antibody concentration but was not selected as a predictor of fertilization. We conclude that the nature of the antigen against which the seminal antisperm antibody is directed may be as important as the antibody concentration in affecting sperm function. There seems to be little practical value in measuring IgM in seminal plasma.
Adult↗
Bacteriocins of gram-positive bacteria.
In recent years, a group of antibacterial proteins produced by gram-positive bacteria have attracted great interest in their potential use as food preservatives and as antibacterial agents to combat certain infections due to gram-positive pathogenic bacteria. They are ribosomally synthesized peptides of 30 to less than 60 amino acids, with a narrow to wide antibacterial spectrum against gram-positive bacteria; the antibacterial property is heat stable, and a producer strain displays a degree of specific self-protection against its own antibacterial peptide. In many respects, these proteins are quite different from the colicins and other bacteriocins produced by gram-negative bacteria, yet customarily they also are grouped as bacteriocins. Although a large number of these bacteriocins (or bacteriocin-like inhibitory substances) have been reported, only a few have been studied in detail for their mode of action, amino acid sequence, genetic characteristics, and biosynthesis mechanisms. Nevertheless, in general, they appear to be translated as inactive prepeptides containing an N-terminal leader sequence and a C-terminal propeptide component. During posttranslational modifications, the leader peptide is removed. In addition, depending on the particular type, some amino acids in the propeptide components may undergo either dehydration and thioether ring formation to produce lanthionine and beta-methyl lanthionine (as in lantibiotics) or thio ester ring formation to form cystine (as in thiolbiotics). Some of these steps, as well as the translocation of the molecules through the cytoplasmic membrane and producer self-protection against the homologous bacteriocin, are mediated through specific proteins (enzymes). Limited genetic studies have shown that the structural gene for such a bacteriocin and the genes encoding proteins associated with immunity, translocation, and processing are present in a cluster in either a plasmid, the chromosome, or a transposon. Following posttranslational modification and depending on the pH, the molecules may either be released into the environment or remain bound to the cell wall. The antibacterial action against a sensitive cell of a gram-positive strain is produced principally by destabilization of membrane functions. Under certain conditions, gram-negative bacterial cells can also be sensitive to some of these molecules. By application of site-specific mutagenesis, bacteriocin variants which may differ in their antimicrobial spectrum and physicochemical characteristics can be produced. Research activity in this field has grown remarkably but sometimes with an undisciplined regard for conformity in the definition, naming, and categorization of these molecules and their genetic effectors. Some suggestions for improved standardization of nomenclature are offered.
Amino Acid Sequence↗
Complete nucleotide sequence of pSMB 74, a plasmid encoding the production of pediocin AcH in Pediococcus acidilactici.
Several Pediococcus acidilactici strains produce a plasmid-encoded bacteriocin, pediocin AcH. Previous studies have shown that this plasmid, designated as pSMB 74, encodes genes associated with the production of prepediocin, its post-translation processing to pediocin AcH, transmembrane translocation of these molecules, and immunity of producer cells against pediocin AcH. We report here the complete nucleotide sequence of pSMB 74. The plasmid has a total of 8877 bp. Four genes have been located on pSMB 74. The genes are arranged in a gene cluster of 3500 bp and share a common promoter and rho-independent stem-loop terminator. The four genes, each with independent ribosome binding sites (rbs), initiation and termination codons and spacer sequences in between, were designated as pap A, pap B, pap C and pap D and encode respectively for proteins of 62, 112, 174 and 724 amino acids. The results of this study can be useful either to introduce a suitable marker at a unique restriction site in pSMB 74 and use it as a vector or to clone the pap gene cluster in a suitable plasmid and transform desirable strains for pediocin AcH production. The gene sequence has been submitted to Gene Bank (Acc. No. U02482).
Amino Acid Sequence↗
Hydrostatic pressure and electroporation have increased bactericidal efficiency in combination with bacteriocins.
We report here that both ultrahigh hydrostatic pressure (UHP) and electroporation (EP) induced sublethal injury to bacterial cells surviving the treatments. The injured cells of both gram-positive and -negative bacteria became sensitive to the bacteriocins pediocin AcH and nisin. Bacteriocins in combination with either UHP or EP have greater antibacterial effectiveness than UHP or EP alone.
Journal Article↗
Analysis of the pediocin AcH gene cluster from plasmid pSMB74 and its expression in a pediocin-negative Pediococcus acidilactici strain.
The 3,500-bp pap operon in the 8,877-bp plasmid pSMB74 contains a cluster of four genes, papABCD, of which papA encodes prepediocin (A. M. Motlagh, M. Bukhtiyarova, and B. Ray, Lett. Appl. Microbiol. 18:305-312, 1994). The cluster without the promoter was cloned in the shuttle vector pHPS9. An Escherichia coli strain and a pediocin-sensitive Pediococcus acidilactici strain transformed with the recombinant plasmid, pMBR1.0, produced pediocin AcH. Deletion analysis by introducing mutations in the four genes in pMBR1.0 revealed that only papA and papD were required for pediocin AcH production and that the gene product of papD has both translocation and processing functions. In the transformed minicells of E. coli chi 925 the proteins of the pap cluster were synthesized, indicating no polar effect due to deletion.
Bacteriocins↗
Impact of prolactin on epididymal lipid profile in castrated rats.
Prolactin treatment to castrated rats led to accumulation of triacylglycerol and esterified cholesterol. There was no appreciable drift in epididymal cholesterol: phospholipid ratio between the prolactin treated and control animals. However, further analysis of phospholipids showed a build up of phosphatidyl inositol, phosphatidyl choline and phosphatidyl ethanolamine but a drop in the levels of phosphatidyl serine and sphingomyelin in prolactin treated castrated rats as compared to those castrated animals injected with vehicle alone. Changes in phospholipids reported above were prominently seen in the group of castrated rats that received 100 micrograms oPRL/100 g body weight but not in those animals which received either lower or higher doses of the hormone. Interestingly, bromocryptine treatment in castrated rats produced a general depletion in the levels of all lipid classes studied in the epididymis. It is suggested that this may be due to impaired synthesis and/or increased breakdown of lipids in this organ.
Animals↗
Nucleotide and amino acid sequence of pap-gene (pediocin AcH production) in Pediococcus acidilactici H.
N-terminal analysis of purified pediocin AcH produced a partial sequence of 23 amino acids. This sequence matched perfectly with a segment of 23 amino acids in a 62 amino acid molecule generated from the 186 nucleotide sequence open reading frame in a Hind III fragment in pSMB74 encoding pap-gene (pediocin AcH production). It is suggested that the molecule is translated as inactive prepediocin AcH of 62 amino acids. Then through enzymatic modifications the leader segment of 18 amino acids is removed from the NH2-terminal. The remaining segment of 44 amino acids is active pediocin AcH of 4628 M(r).
Amino Acid Sequence↗
Novel method to extract large amounts of bacteriocins from lactic acid bacteria.
Antimicrobial peptides, bacteriocins, produced by lactic acid bacteria were adsorbed on the cells of producing strains and other gram-positive bacteria. pH was a crucial factor in determining the degree of adsorption of these peptides onto cell surfaces. In general, between 93 and 100% of the bacteriocin molecules were adsorbed at pHs near 6.0, and the lowest (< or = 5%) adsorption took place at pH 1.5 to 2.0. On the basis of this property, a novel isolation method was developed for bacteriocins from four genera of lactic acid bacteria. By using this method we made preparations of pediocin AcH, nisin, sakacin A, and leuconocin Lcm1 that were potent and concentrated. This method produced a higher yield than isolation procedures, which rely on precipitation of the bacteriocins from the cell-free culture liquor. It is simple and can be used to produce large quantities of bacteriocins from lactic acid bacteria to be used as food biopreservatives.
Adsorption↗
Influence of Growth Conditions on the Production of a Bacteriocin, Pediocin AcH, by Pediococcus acidilactici H.
The influence of growth parameters on the production of pediocin AcH by Pediococcus acidilactici H was studied. This strain produced large quantities of pediocin AcH in TGE broth (Trypticase [1%], glucose [1%], yeast extract [1%], Tween 80 [0.2%], Mn [0.033 mM], Mg [0.02 mM] [pH 6.5]) within 16 to 18 h at 30 to 37 degrees C (final pH, 3.6 to 3.7). Pediocin AcH production was negligible when the pH of the medium was maintained at 5.0 or above, even in the presence of high cell mass.
Journal Article↗
Effect of spray-chilling on quality of beef from lean and fatter carcasses.
Carcasses from five trim cows and five choice steers were used to study the effects of spray-chilling on cooler shrink, chill rate, purge loss from vacuum-packaged cuts, cook loss, shear values and bacterial growth. Spray-chilling reduced cooler shrink but had no effect on chill rate, purge loss from vacuum-packaged cuts, cook loss or shear values. Aerobes, facultative anaerobes, aerobic psychrotrophs, facultative anaerobic psychrotrophs and lactic acid bacteria all tended to be higher on rounds from spray-chilled sides. Leaner (and lighter) cow carcasses chilled faster and had lost a higher percentage of their weight at 24 h than fatter and heavier steer carcasses. The leaner carcasses had higher bacterial counts initially and throughout storage. This difference may have been due to differences in the level of initial contamination during dressing and not due to the carcasses' leanness. Purge-weight loss for each carcass increased and cooking weight loss decreased with increased storage times, making the total weight loss from meat aged 5 vs 10 wk similar.
Animals↗
Antigenic property of pediocin AcH produced by Pediococcus acidilactici H.
Pediocin AcH, a bacteriocin of Pediococcus acidilactici H, inhibits the growth of several food spoilage and pathogenic bacteria. The antigenic property of partially purified pediocin AcH was tested by immunizing mice and a rabbit. Pediocin AcH was not immunogenic in these animals as determined by immunoblotting even after conjugation to bovine serum albumin. The non-immunogenic nature of pediocin AcH, its non-toxicity to laboratory animals and its hydrolysis by gastric proteolytic enzymes may be considered favourably in its possible use as a food preservative.
Animals↗
Purification, characterization and antimicrobial spectrum of a bacteriocin produced by Pediococcus acidilactici.
An antimicrobial peptide designated pediocin AcH was isolated from Pediococcus acidilactici strain H. The pediocin AcH was purified by ion exchange chromatography. The molecular weight of pediocin AcH was determined by SDS-PAGE to be about 2700 daltons. Pediocin AcH was sensitive to proteolytic enzymes resistant to heat and organic solvents, and active over a wide range of pH. Pediocin AcH exhibited inhibition against several food spoilage bacteria and foodborne pathogens including Staphylococcus aureus, Clostridium perfringens and Listeria monocytogenes. It was bactericidal to sensitive cells and acted very rapidly. The bactericidal effect was not produced by either cell lysis or apparent loss of membrane permeability.
Bacteria↗
Selection of Lactobacillus acidophilus strains for use in "acidophilus products".
Recent studies by DNA-DNA hybridization revealed that strains now designated as L. acidophilus, can be divided into several groups and only one group should be classified as L. acidophilus. We studied several phenotypic characteristics in representative strains from the six DNA-homology groups of L. acidophilus. No group specific pattern was observed among the strains for fermentation of eight carbohydrates, growth at 15 and 45 degrees C, resistance to 0.2% oxgall, lysis by lysozyme or sensitivity to 17 antibiotics. However, some differences among groups were observed in beta-galactosidase (beta-gal) activity and surface layer (s-layer) protein. Strains in B1 do not have a s-layer or beta-gal while B2 strains also lack a s-layer but do possess beta-gal. All strains in groups A1, A2, A3 and A4, capable of growing in lactose, have beta-gal activity and also have a s-layer composed of protein subunits of different molecular weights (MW). Strains in A1 homology group have a s-layer with 46 Kd protein subunits while strains in other A groups have s-layer protein subunits that varied in MW within each group. On the basis of these two traits several isolates of unknown homology groups have been tentatively placed in A1, B1 or B2 groups. L. acidophilus from A1 group showed strain variation in beta-gal specific activity and rate of acid production and growth. For use in dietary adjuncts, L. acidophilus strains should be selected for these three and other desirable traits. They should be maintained and grown in media containing lactose.
Bacterial Outer Membrane Proteins↗
Philosophy, computers, vendors and hospitals.
Explore the source record for details and available documents.
Computers↗
Comparative in vitro inhibitory activities of novel beta-lactam compounds against multiresistant beta-lactamase producing Staphylococcus aureus.
Explore the source record for details and available documents.
Clavulanic Acids↗
Genetic and biochemical analysis of mutation(s) affecting ricin internalization in Chinese hamster ovary cells.
We have previously reported the isolation and characterization of Chinese hamster ovary (CHO) cell mutants defective in the internalization of ricin (Ray, B., and Wu, H.C. (1982) Mol. Cell. Biol. 2, 535-544). These mutants also do not exhibit the enhancement of ricin internalization by nigericin pretreatment at a low concentration, which is observed in the wild-type CHO cells. An analysis of somatic cell hybrids between the mutant and the toxin-sensitive wild-type CHO cell line shows that all of the phenotypes associated with the toxin resistance mutation are dominant in the hybrid cell lines. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of [3H]palmitic acid-labeled cell extracts from the mutant and toxin-resistant hybrid cell lines has revealed an increased incorporation of [3H] palmitic acid into two proteins with apparent molecular weights near 30,000 in the mutant and hybrid cells as compared to that in the wild-type cell line. Our studies indicate that these two fatty acyl proteins might be related to a dominant mutation(s) which results in a decreased uptake of ricin.
Animals↗
[Endobronchial non-Hodgkin's lymphoma].
The authors report a case of endobronchial non-Hodgkin lymphoma, in a 48-year-old woman. This is an exceptional localization. When it reveals the disease, as was the case in the index patient, clinical presentation is usually atelectasis with fever. Diagnosis was established upon bronchoscopy. Histologic examination of biopsy specimens showed an immunoblastic lymphosarcoma. Total pneumonectomy and chemotherapy failed to prevent rapid deterioration with a fatal outcome 7 months after onset. A selective total IgA deficiency and a familial history of malignant tumors were recorded. Immunoblastic sarcoma has a poor prognosis. It often follows a disease whose mechanism is ascribed to an immunological disorder. Lymphoma arising in a patients with prior immune disease should suggest the diagnosis of immunoblastic sarcoma.
Adolescent↗