Analysis of neutral glycosphingolipids from Trypanosoma brucei

Neutral glycosphingolipids (GSLs) were isolated from Trypanosoma brucei and analyzed by thin-layer chromatography (TLC), TLC/secondary ion mass spectrometry (TLC/SIMS), and liposome immune lysis assay (LILA). Three species of neutral GSLs, designated as N-1, -2, and -3 were separated on TLC. N-1 GSL migrated very close to glucosylceramide (GlcCer) and N-2 GSL showed the same mobility as lactosylceramide (LacCer). On the other hand, the mobility of N-3 GSL on the TLC plate was slower than globotetraosylceramide (Gb4). In order to characterize the molecular species of neutral GSLs from T. brucei, N-1, -2 and -3 GSLs were analyzed by TLC/SIMS. The TLC/SIMS analysis of N-1 of the parasites revealed a series of (M–H)⁻ ions from m/z 698 to 825 representing the molecular mass range of ceramide monohexoside (CMH) (GlcCer or galactosylceramide). On the other hand, the TLC/SIMS spectra of N-2 GSL revealed a series of (M–H)⁻ ions from m/z 944–987 indicating the molecular mass range of LacCer. In the TLC/SIMS analysis of N-3 GSL, however, the characteristic molecular ions that can elucidate the structure of N-3 GSL were not obtained. In order to confirm the results obtained from TLC/SIMS, N-1, -2, and -3, GSLs were tested by LILA with specific antibodies against GlcCer, LacCer, and Gb4, respectively. N-1 GSL had reactivity to anti-GlcCer antibody and N-2 GSL reacted with the antibody against LacCer. However, N-3 GSL was not recognized by anti-Gb4 antibody. Using anti-GlcCer and anti-LacCer antibodies, furthermore, we studied the expression of GlcCer and LacCer in T. brucei parasites. Both GlcCer and LacCer were detected on the cell surface of T. brucei.     

Changes in circulating adiponectin and metabolic hormone concentrations during periparturient and lactation periods in Holstein dairy cows

Although our previous report demonstrated that adiponectin and AdipoR1 gene expressions changed among different lactation stages in the bovine mammary gland, its in vivo kinetics remain unclear in ruminant animals. In this study, we investigated the changes in circulating concentrations of adiponectin, as well as other metabolic hormones and metabolites, (i) during the periparturient period and (ii) among different lactation stages, in Holstein dairy cows. In experiment 1, serum adiponectin concentrations increased after parturition. Serum insulin concentrations were lower in the postpartum than prepartum period, whereas serum growth hormone (GH) concentrations increased in the postpartum period. Serum nonesterified fatty acids (NEFA) levels were increased during the postpartum period and were dependent on the parity. In experiment 2, there was no significant difference in plasma adiponectin concentrations among lactational stages. Plasma insulin concentrations tended to be lower in early lactation while plasma GH levels tended to be higher. Plasma NEFA concentrations were significantly lower in mid‐ and late‐lactation stages than non‐lactation stages. These findings indicate that elevation of serum adiponectin might be involved in energy metabolism just around parturition, and might exert its action through regulation of receptor expression levels in target tissues in each lactational stage in Holstein dairy cows.     

Japanese black cattle with ateliosis showed lower insulin responses during glucose tolerance test

In order to determine insulin secretability and glucose utilization, a glucose tolerance test was performed in ateliotic cattle of 2 paternal strains; MHO and HSK cattle. MHO and HSK cattle showed different endocrine patterns in our previous study. Area under the insulin concentration curves (insulin-AUC) in the ateliotic cattle were significantly lower (122.3 +/- 59.4 ng.min/ml and 99.2 +/- 24.8 ng.min/ml for MHO and HSK cattle, respectively) than the control cattle (420.2 +/- 175.2 ng.min/ml). These low insulin responses to GTT may have an influence on growth retardation in MHO and HSK cattle.     

Detection of fungi producing infection-inhibiting metabolites against <Emphasis Type="Italic">Alternaria alternata</Emphasis> Japanese pear pathotype from fungi inhabiting internal tissues of Japanese pear shoots

Fungi inhabiting Japanese pear were isolated from internal tissues of cv. Nijisseiki, and culture filtrates (CFs) of 100 isolates were evaluated for their inhibitory activity against infection by Alternaria alternata Japanese pear pathotype. CFs of 11 isolates inhibited lesion formation on the pear by the pathogen. Among these isolates, CFs of five isolates inhibited spore germination. CFs of the six other isolates inhibited appressorial formation, infection hypha formation, AK-toxin production, or a combination of these actions. Analysis of sequence homology in the rDNA ITS1 regions of these isolates showed that most isolates had high homology with some fungal endophytes.     

Inhibition of growth hormone secretagogue receptor antagonist, [D-Lys-3]-GHRP-6, in adipogenesis of ovine and rat adipocytes

Ghrelin and growth hormone secretagogues receptor (GHS‐R or ghrelin receptor) have been reported as being one of the factors of adipogenesis in adipocytes. To investigate the involvement of ghrelin and GHS‐R in adipocytes, the effect of the GHS‐R antagonist, [D‐Lys‐3]‐GHRP‐6 (His‐D‐Trp‐D‐Lys‐Trp‐D‐Phe‐Lys‐NH₂), on the process of adipogenesis in ovine and rat adipocytes was evaluated. [D‐Lys‐3]‐GHRP‐6 (10^?7 mol/L) significantly inhibited adipogenic differentiation of ovine and rat preadipocytes prepared from adipose tissues. The level of peroxisome proliferator activated receptor (PPAR)‐γ2 mRNA, an adipogenic marker, was decreased during the differentiation of adipocytes treated with [D‐Lys‐3]‐GHRP‐6 for 10 days. Ghrelin stimulated adipogenesis, also causing an increment of glycerol‐3‐phosphate dehydrogenase and upregulation of PPAR‐γ2. Furthermore, the antilipolytic effect of ghrelin was attenuated by treatment with [D‐Lys‐3]‐GHRP‐6 in both types of isolated adipocytes. Overall, the results of the present study highlight that GHS‐R in adipogenesis can be blocked by treatment with [D‐Lys‐3]‐GHRP‐6.     

Heritability estimates of liabilities to digestive diseases in heavy racehorses

Data on 1410 heavy racehorses were taken from the Hokkaido Banei Horse Racing Result Book published during 1997–2000. Heritabilities were estimated using the restricted maximum likelihood method with a full data set of the accumulated prize winnings and the frequency of medical treatment against digestive diseases. Heritability estimates for the same traits were also obtained using a partial data set from affected animals only. In addition, a ‘two classes, one threshold’ model was applied to the full data set for the heritability estimation of liability to the diseases. Heritabilities estimated by restricted maximum likelihood with the full data set were quite low: 0.09 ± 0.02 for the prize winnings and 0.08 ± 0.03 for all three digestive diseases – colic resulting from flatulence, constipation and overfeeding. Low heritabilities were also estimated for each of the three kinds of colic. Medium heritabilities were estimated for colic resulting from constipation (0.30 ± 0.19) and overfeeding (0.46 ± 0.22) using the partial data set taken from the affected animals. Using the threshold model, higher heritabilities from 0.42 ± 0.04 to 0.57 ± 0.03 were estimated for the liabilities to all three digestive diseases and to the individual digestive diseases. These results suggest that liability evaluation of the frequency of medical treatment is insufficient because all non‐affected animals are scored as 0. The high heritabilities estimated by the threshold model with half‐sib relationships should be verified in future studies by comparing them with estimates from other genetic relationships and with realized heritabilities from a small‐scale practical selection program.     

Bacterial Leaf Spot of Ivy Caused by Xanthomonas campestris pv. hederae

A bacterial leaf spot disease was observed on Hedera helix (English ivy) and H. canariensis (Algerian ivy) in Japan. The causal agent was identified as Xanthomonas campestris pv. hederae (Arnaud 1920) Dye 1978. Received 13 May 2002/ Accepted in revised form 3 July 2002     

Computer tomography diagnosis of meningoencephalocele in a calf

A 24-day-old female Holstein calf had a soft, painless fluctuating swelling on the median plane in the frontal region, but did not show any clinical symptoms including neurological signs. Computer tomography (CT) distinctly showed the cyst filled with fluid and part of the encephalon. Hence, this swelling was diagnosed as meningoencephalocele, but not meningocele. The meningoencephalocele was successfully repaired surgically. Meningoencephalocele can thus be easily recognised by CT in a calf.     

Pedigree analysis of factor XI deficiency in Japanese black cattle

Using a DNA-based diagnostic test for factor XI deficiency in Japanese black cattle, we surveyed 123 cattle (42 sires and 81 dams) in Gifu and Hyogo prefectures, and calculated gene frequencies. In sires, we drew up the pedigree network of the cattle with the factor XI deficiency. Results showed that the mutated allele of factor XI deficiency was retroactive in at least 6 or more generations of sires. Frequencies of the mutant gene were higher at 26.4% in total, and at 33.3% in sires. All 7 cattle with the homozygote of mutated allele were clinically normal, and showed no bleeding episodes. The mutated allele of factor XI deficiency might be widespread among Japanese black cattle.     

Effect of oral administration of colostrum on inflammation in the udders of dairy cows suffering from mastitis

The present study was undertaken to examine whether oral administration of colostrum to mastitic cows reduced inflammation in the udder. Fifty milliliters of a colostrum whey product was administered orally daily for 3 days to cows suffering from mastitis. Milk was collected on day 0 and 7 of colostrum administration. For Experiment 1, milk from 11 udder quarters with high somatic cell counts (SCC) in four cows was used. SCC in milk decreased significantly after colostrum administration, whereas colostrum administration increased sodium and IgA concentrations significantly compared with those before administration. In Experiment 2, cows with clinical mastitis were divided into two groups, with and without colostrum administration, whereas all cows with subclinical mastitis were administered colostrum. Antibiotics were infused into the mammary gland from the first day of colostrum administration for 2–4 days. There was no significant decrease in SCC after colostrum administration in any group. However, udder firmness in both clinical mastitis groups was reduced after administration regardless of colostrum administration. IgA concentration in both clinical mastitis groups was significantly increased after colostrum administration compared to that before administration, although there was no significant difference between them. These results suggest the possibility that oral administration of colostrum attenuates inflammation of the mammary gland. Further studies are required to examine the effect of colostrum more precisely using cows with subclinical and chronic mastitis and longer duration of colostrum administration.