Influence of endophyte-infected tall fescue on cyclicity, pregnancy rate and early embryonic loss in the mare

The effects of grazing endophyte-infected tall fescue on luteal function, pregnancy rates, and embryonic loss rates were compared between treated mares (n=18) and untreated controls (endophyte-free, n=12). Mares grazing endophyte-infected fescue demonstrated significantly (P<0.01) prolonged luteal function (22.9 vs 15.8 d) than those grazing endophyte-free fescue. Continuous grazing of endophyte-infected fescue resulted in a decreased (P=0.30) per cycle 14-d viable pregnancy rate (14 31 , 45.2%) compared with that of endophyte-free grazing (12 16 , 75.0%). Early embryonic death rates were higher (P=0.20) in the endophyte-infected group (6 20 , 30.0%) than the endophyte-free group (1 13 , 7.7%). Cumulative pregnancy rates after a 60-d breeding period did not differ between the 2 groups. Embryonic development based on mean vesicle height at 14-d was not significantly different between treatment groups for embryos that maintained viability. Embryos that underwent early embryonic death were smaller (P<0.10) at Day-14 than embryos that maintained viability. Mean plasma progesterone concentrations were significantly (P< 0.01) greater at Day-21 postovulation in endophyte-infected mares in which the embryo remained viable (15.8 ng/ml) than in endophyte-free mares that experienced early embryonic death (9.8 ng/ml) or that demonstrated prolongation of luteal function (11.2 ng/ml). The results of this study suggest that grazing endophyte-infected tall fescue can have a detrimental effect on reproductive efficiency in the mare due to an increase in cycles bred per pregnancy rate, increased early embryonic death rate and prolongation of luteal function.     

Screening for ethanol-producing filamentous fungi

Of nineteen Aspergilli and ten Rhizopus strains examined for their ability to ferment simple sugars (glucose, xylose, and arabinose) as well as complex substrates (cellulose, oat-spelt xylan, corn fiber, and corn germ pressing), three Rhizopus strains were identified that could produce more than 31 g ethanol/l under anaerobic stress. By 72 h, glucose , xylose, cellobiose, and corn fiber were fermented with perspective yields of 100, 47, 80, and 40 percent, of theoretical.     

Characteristics of apolipophorin-III of the southwestern corn borer, Diatraea grandiosella

Apolipophorin-III was isolated from the lipophorin-free fraction of larval plasma of the southwestern corn borer, Diatraea grandiosella, because significant amounts of apolipophorin-III were found to be present in the hemolymph not associated with lipophorin. Apolipophorin-III, purified using ammonium sulfate precipitation, cation exchange chromatography, and gel filtration, was shown to be a nonglycosylated polypeptide with 17 kDa mol. wt, as determined by SDS-PAGE and silver staining. The amino acid composition of apolipophorin-III showed similarities to published compositions of apolipophorin-III isolated from other insects. The N-terminal sequence of apolipophorin-III (DAPSTTPPQDXEKKAAEFQKTFTEQXNQLANK), is highly homologous to that of apolipophorin-III of Manduca sexta. Antiserum raised against purified apolipophorin-III was used to demonstrate an immunochemical identity between the isolated apolipophorin-III and that associated with lipophorin. This antiserum cross-reacted with apolipophorin-III of M. sexta, and antiserum raised against M. sexta apolipophorin-III cross-reacted with apolipophorin-III isolated from D. grandiosella, demonstrating an immunochemical relationship between the proteins, and providing confirmatory evidence for the identity of the isolated protein. These antisera did not react with the putative apolipophorin-III of the cricket, Acheta domesticus. Using immunoprecipitation by the apolipophorin-III antiserum of D. grandiosella, the synthesis and secretion of [³H]apolipophorin-III by the fat body in vitro was shown to be maximal in 13–15 day-old larvae, with a transit time of ca 23 min.     

CENP-A associated complex satellite DNA in the kinetochore of the Indian muntjac

The centromere/kinetochore complex is a chromosomal assembly that mediates chromosome motility and mitotic regulation by interacting with microtubules of the mitotic spindle apparatus. Centromere protein A (CENP-A) is a histone H3 homolog that is concentrated in the chromatin of the inner kinetochore plate of human chromosomes. To identify DNA sequences associated with the inner kinetochore plate, we used anticentromere autoantibodies to immunoprecipitate CENP-A associated chromatin selectively from Indian muntjac fibroblasts. DNA was cloned from immunoprecipitated CENP-A- associated chromatin and characterized by DNA sequence and hybridization analyses. A novel centromeric satellite DNA sequence was identified and shown by fluorescence in situ hybridization analysis to be present at all centromeres of the Indian muntjac. This satellite DNA constitutes a 972 bp monomer repeat and shows partial homology with satellite II DNA of the white-tailed deer. Southern blot analysis of muntjac genomic DNA suggests that this satellite DNA is present in repetitive tandem arrays and contains complex internal arrangements. In conjunction with previous work showing the association of CENP-A with human α-satellite DNA, we conclude that the mammalian inner kinetochore plate contains a unique form of chromatin that contains CENP-A in association with complex satellite DNA. Received: 18 May 1999; in revised form: 5 July 1999 / Accepted: 20 July 1999     

Th2 cytokines and asthma — The role of interleukin-5 in allergic eosinophilic disease

Interleukin-5 is produced by a number of cell types, and is responsible for the maturation and release of eosinophils in the bone marrow. In humans, interleukin-5 is a very selective cytokine as a result of the restricted expression of the interleukin-5 receptor on eosinophils and basophils. Eosinophils are a prominent feature in the pulmonary inflammation that is associated with allergic airway diseases, suggesting that inhibition of interleukin-5 is a viable treatment. The present review addresses the data that relate interleukin-5 to pulmonary inflammation and function in animal models, and the use of neutralizing anti-interleukin-5 monoclonal antibodies for the treatment of asthma in humans.     

Antioxidant effects of green tea and its polyphenols on bladder cells

Genitourinary tract inflammation/ailments affect the quality of life and health of a large segment of society. In recent years, studies have demonstrated strong antioxidant effects of green tea and its associated polyphenols in inflammatory states. This in vitro study examined the antioxidant capabilities (and putative mechanisms of action) of green tea extract (GTE), polyphenon-60 (PP-60, 60% pure polyphenols), (-)-epicatechin-3-gallate (ECG) and (-)-epigallocatechin-3-gallate (EGCG) in normal/malignant human bladder cells following catechin treatment+/-1 mM H2O2 (oxidative agent). Cell viability, apoptosis and reactive oxygen species (ROS) formation were evaluated. Our results showed that H2O2 exposure significantly reduced normal (UROtsa) and high-grade (TCCSUP, T24) bladder cancer (BlCa) cell viability compared with control-treated cells (p<0.001). No affect on low-grade RT4 and SW780 BlCa cell viability was observed with exposure to H2O2. Compared to H2O2-treated UROtsa, treatment with PP-60, ECG and EGCG in the presence of H2O2 significantly improved UROtsa viability (p<0.01), with strongest effects evoked by ECG. Additionally, though not as effective as in UROtsa cells, viability of both high-grade TCCSUP and T24 BlCa cells, in comparison to H2O2-treated cells, was significantly improved (p<0.01) by treatment with PP-60, ECG, and EGCG in the presence of H2O2. Overall, our findings demonstrate that urothelium cell death via H2O2-induced oxidative stress is mediated, in part, through superoxide (O2-.;), and potentially, direct H2O2 mechanisms, suggesting that green tea polyphenols can protect against oxidative stress/damage and bladder cell death.     

MHC class I characterization of Indonesian cynomolgus macaques

Cynomolgus macaques (Macaca fascicularis) are quickly becoming a useful model for infectious disease and transplantation research. Even though cynomolgus macaques from different geographic regions are used for these studies, there has been limited characterization of full-length major histocompatibility complex (MHC) class I immunogenetics of distinct geographic populations. Here, we identified 48 MHC class I cDNA nucleotide sequences in eleven Indonesian cynomolgus macaques, including 41 novel Mafa-A and Mafa-B sequences. We found seven MHC class I sequences in Indonesian macaques that were identical to MHC class I sequences identified in Malaysian or Mauritian macaques. Sharing of nucleotide sequences between these geographically distinct populations is also consistent with the hypothesis that Indonesia was a source of the Mauritian macaque population. In addition, we found that the Indonesian cDNA sequence Mafa-B7601 is identical throughout its peptide binding domain to Mamu-B03, an allele that has been associated with control of Simian immunodeficiency virus (SIV) viremia in Indian rhesus macaques. Overall, a better understanding of the MHC class I alleles present in Indonesian cynomolgus macaques improves their value as a model for disease research, and it better defines the biogeography of cynomolgus macaques throughout Southeast Asia.     

Clostridium beijerinckii and Clostridium difficile Detoxify Methylglyoxal by a Novel Mechanism Involving Glycerol Dehydrogenase

In contrast to gram-negative bacteria, little is known about the mechanisms by which gram-positive bacteria degrade the toxic metabolic intermediate methylglyoxal (MG). Clostridium beijerinckii BR54, a Tn1545 insertion mutant of the NCIMB 8052 strain, formed cultures that contained significantly more (free) MG than wild-type cultures. Moreover, BR54 was more sensitive to growth inhibition by added MG than the wild type, suggesting that it has a reduced ability to degrade MG. The single copy of Tn1545 in this strain lies just downstream from gldA, encoding glycerol dehydrogenase. As a result of antisense RNA production, cell extracts of BR54 possess significantly less glycerol dehydrogenase activity than wild-type cell extracts (H. Liyanage, M. Young, and E. R. Kashket, J. Mol. Microbiol. Biotechnol. 2:87–93, 2000). Inactivation of gldA in both C. beijerinckii and Clostridium difficile gave rise to pinpoint colonies that could not be subcultured, indicating that glycerol dehydrogenase performs an essential function in both organisms. We propose that this role is detoxification of MG. To our knowledge, this is the first report of targeted gene disruption in the C. difficile chromosome.     

The little skate Raja erinacea exhibits an extrahepatic ornithine urea cycle in the muscle and modulates nitrogen metabolism during low-salinity challenge

Urea synthesis via the hepatic ornithine urea cycle (OUC) has been well described in elasmobranchs, but it is unknown whether OUC enzymes are also present in extrahepatic tissues. Muscle and liver urea, trimethylamine oxide (TMAO), and other organic osmolytes, as well as selected OUC enzymes (carbamoyl phosphate synthetase III, ornithine transcarbamoylase, arginase, and the accessory enzyme glutamine synthetase), were measured in adult little skates (Raja erinacea) exposed to 100% or 75% seawater for 5 d. Activities of all four OUC enzymes were detected in the muscle. There were no changes in muscle OUC activities in skates exposed to 75% seawater; however, arginase activity was significantly lower in the liver, compared to controls. Urea, TMAO, and several other osmolytes were significantly lower in the muscle of little skates exposed to 75% seawater, whereas only glycerophosphorylcholine was significantly lower in the liver. Urea excretion rates were twofold higher in skates exposed to 75% seawater. Taken together, these data suggest that a functional OUC may be present in the skeletal muscle tissues of R. erinacea. As well, enhanced urea excretion rates and the downregulation of the anchor OUC enzyme, arginase, in the liver may be critical in regulating tissue urea content under dilute-seawater stress.