Antioxidative properties of phenolic antioxidants isolated from corn steep liquor

With the immersion of corn into dilute sulfur oxide during starch-manufacturing processes, corn steep liquor (CSL) remains as leftover material. CSL is often used for fermentation, but its components are not fully understood. To determine the properties of CSL, 12 p-coumaric acid-related compounds were isolated from an ethyl acetate extract of CSL with the guidance of antioxidative activity on the rabbit erythrocyte membrane ghost system. The activity of these compounds was compared against oxidative damages, and it was elucidated that the activity of p-coumaric acid derivatives was mainly affected by their functional groups at the 3-position and less by the conjugated side chain. Moreover, p-coumaric acid derivatives exhibited inhibitory activity stronger than that of tocopherols and ascorbic acid on peroxynitrite-mediated lipoprotein nitration. These findings that p-coumaric acid derivatives, which might play a beneficial role against oxidative damage, exist in CSL suggest this byproduct might be a useful resource of phenolic antioxidants.     

Novel flavonol glycoside, 7-O-methyl mearnsitrin, from Sageretia theezans and its antioxidant effect

A novel flavonol glycoside, 7-O-methylmearnsitrin (7,4'-O-dimethylmyricetin 3-O-alpha-L-rhamnopyranoside), and myricetrin, kaempferol 3-O-alpha-L-rhamnopyranoside, europetin 3-O-alpha-L-rhamnoside, and 7-O-methyl quercetin 3-O-alpha-L-rhamnopyranoside were isolated from the leaves of Sageretia theezans, and their chemical structures were identified by spectroscopic analyses including two-dimensional NMR (HSQC, HMBC). Whereas myricetrin, europetin 3-O-alpha-L-rhamnoside, and 7-O-methylquercetin 3-O-alpha-L-rhamnopyranoside showed stronger activities than ascorbic acid and alpha-tocopherol, 7-O-methylmearnsitrin showed very weak antioxidant activities by ESR and LDL oxidation inhibition tests.     

Effects of partial removal of cytoplasmic lipid on survival of vitrified germinal vesicle stage pig oocytes

This study was designed to investigate whether the partial removal of cytoplasmic lipid from immature pig oocytes prior to vitrification had any positive effects on subsequent maturation, fertilization and early development. Oocytes at the germinal vesicle stage were partially freed from cumulus cells and centrifuged, and then polarized cytoplasmic lipid was removed by micromanipulation. When cultured for 44-48 h, significantly fewer of the centrifuged oocytes reached metaphase II (M-II) than did the non-centrifuged oocytes (approximately 53% vs approximately 68%, respectively); however, no further reduction in the M-II rate was observed when centrifuged oocytes were then delipated prior to culture (approximately 47%). To evaluate their sensitivity to the equilibration and vitrification solutions containing ethylene glycol, non-centrifuged, centrifuged, and delipated oocytes were cultured continuously for several minutes in those solutions, then washed and cultured further; no significant differences in the M-II rates (approximately 20-27%) were observed among the three treatment groups. When oocytes were vitrified and then warmed, significantly more delipated oocytes reached M-II in culture (approximately 15%) than did the non-delipated oocytes, whether centrifuged or not (approximately 4% in each group). When delipated, vitrified and matured oocytes were microsurgically injected with frozen-thawed spermatozoa, approximately 39% were activated and male pronucleus formation was observed in approximately 40% of activated oocytes; none developed beyond the 4-cell stage. These results show that maturation in vitro of vitrified pig oocytes can be promoted by partial removal of cytoplasmic lipid prior to vitrification and that the vitrified oocytes can be fertilized, although the embryonic development obtained in this study was limited.     

Acquisition of quinolone resistance and point mutation of the gyrA gene in Campylobacter jejuni isolated from broilers and in vitro-induced resistant strains

A dramatic rise in the number of resistant Campylobacter to quinolones has been documented in human patients and domestic animals. In this study, the mechanism of acquisition of quinolone resistance was studied by detecting point mutations in the gyrA gene of Campylobacter strains obtained from broilers and strains with in vitro-induced resistance. The minimal inhibitory concentrations (MICs) of norfloxacin (NFLX) and ofloxacin (OFLX) for the strains that had no point mutation were slightly increased from the source strain (Campylobacter jejuni ATCC 33560). The MICs of nalidixic acid (NA), NFLX, and OFLX for the strains that had the point mutation at Thr-86 were 100 or 200 microg/ml, 50 microg/ml, and 25 microg/ml, respectively. The MIC of NA for the strain that had a point mutation at Asp-90 higher than those for the strains that had the point mutation at Thr-86, but the MICs of NFLX and OFLX were relatively lower than those for the strains that had point mutation at Thr-86. These findings suggest that the degree of antimicrobial resistance against NA, NFLX, and OFLX in the in vitro-induced C. jejuni strains was associated with the location of the point mutation in gyrA. On the other hand, a point mutation in all seven resistant strains isolated from broilers was located only at Thr-86, while the MICs of the three quinolones varied in each wild strain. This suggests that another mechanism might also be involved in the acquisition of quinolone resistance in C. jejuni wild strains.     

A nucleotide mutation associated with fluoroquinolone resistance observed in gyrA of in vitro obtained Rhodococcus equi mutants

In this study, the quinolone resistance-determining region (QRDR) in gyrA and gyrB of in vitro fluoroquinolone-resistant Rhodococcus equi mutants was sequenced. These mutants were selected from four R. equi strains on blood agar plates containing ciprofloxacin or enrofloxacin. Each mutant became 8- to 64 or greater-fold resistant to fluoroquinolones compared with their parent strains. From the results of sequence analysis of QRDR in gyrA and gyrB, a nucleotide mutation of codon GAC for GGC in gyrA was detected in all mutants, but no mutation was observed in gyrB. This mutation leads to amino acid substitution of Asp for Gly in putative GyrA in R. equi. The position of this substitution corresponds to position 87 of GyrA in Escherichia coli. Our results suggest that the mutation of QRDR in gyrA, which was observed in in vitro fluoroquinolone-resistant R. equi mutants in this study, is closely associated with fluoroquinolone resistance.     

Spontaneous Malignant T Cell Lymphoma in a Young Male Common Marmoset (Callithrix jacchus)

We histopathologically and immunohistochemically investigated a case of malignant lymphoma that spontaneously developed in a male common marmoset at two years of age. Beginning at two years four months of age, the animal had an enlargement of the submandibular and inguinal lymph nodes, small subcutaneous nodules near the right breast and an approximately fivefold increase in peripheral lymphocyte count compared with the previous examination value. The postmortem findings at two years eight months of age showed lymphadenopathy with enlargement of the thymus and spleen. Small- to intermediate-sized neoplastic lymphocytes had diffusely proliferated in the enlarged nodes. The neoplastic cells were pleomorphic and had irregularly shaped nuclei. The nuclear chromatin staining revealed hyperchromatism in the small-sized cells, and the intermediate-sized cells exhibited vesicular staining. An immunohistochemical examination indicated that the neoplastic lymphocytes were positive for CD3 and negative for CD20, thus suggesting that they had originated from T cells. In addition, the proliferation of high endothelial venules and reactive epithelioid histiocytes was observed. Scattered tingible body-laden macrophages were infrequently detected. Neoplastic lymphocytes were also observed in the thymus, spleen, heart, lungs, liver, kidneys, adrenal glands and femoral and sternal bone marrow. This malignant lymphoma in a young male common marmoset was considered to fit the category of “peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS)” according to the new WHO system of classification.     

Epidemic of equine influenza among vaccinated racehorses in Japan in 2007

On August 2007, we encountered equine influenza epidemic by Florida sub-lineage strain (H3N8) in Japan Racing Association's facilities where 4142 racehorses in total were stabled. The number of new febrile cases sharply increased, but the occurrence was rapidly calmed down within 2 weeks. The morbidity rate in these facilities was 12.8% and the subclinical infection rate of healthy racehorses examined by rapid antigen detection tests was 19.4% at the early stage of epidemic. The serological studies along with the low morbidity rate and the existence of numbers of asymptomatically infected racehorses, suggested that the cross-reactivity of the antibodies provided by vaccination against the epidemic strain contributed to reducing the morbidity rate and duration of epidemic.     

Proline-glutamic acid-proline-lysine repetition peptide as an antigen for the serological diagnosis of strangles

The reactivity of the proline-glutamic acid-proline-lysine (PEPK) repetition peptide antigen in 3176 serum samples was investigated to evaluate its utility as an antigen for the serological diagnosis of strangles. The reactivity of the sera of horses infected with Streptococcus equi subspecies equi was high when the peptide had several PEPK repetitions. However, as the number of PEPK repetitions increased, the reactivity of the antigen with the sera of horses infected with Streptococcus equi subspecies zooepidemicus also increased. In horses infected experimentally with S equi, the reactivity of the PEPK antigen with five repetitions increased one week after inoculation and continued to increase during the following four weeks. The optical density (OD) values of test sera from horses infected experimentally with S equi and sera from horses that had recovered from strangles were high. The od values of sera from horses that had recovered from an experimental infection with S zooepidemicus and of sera from healthy horses were comparatively low.