Indole-3-acetic acid biosynthesis in <Emphasis Type="Italic">Aciculosporium take</Emphasis>, a causal agent of witches' broom of bamboo

 Aciculosporium take (Ascomycota; Clavicipitaceae) is a causal agent of witches' broom of bamboo plants. The symptoms of this disease are believed to be induced by plant hormones, particularly auxins. Indole-3-acetic acid (IAA) was identified in cultures of this fungus in an l-tryptophan-supplemented liquid medium. IAA production was confirmed on 30 isolates of A. take from various hosts and locations at levels up to 1 mg/l. The biosynthetic pathway of IAA in A. take culture was examined by analyzing intermediate products and by feeding experiments. The results showed that the indole-3-pyruvic acid pathway (l-tryptophan → indole-3-pyruvic acid → indole acetaldehyde → IAA) was the dominant pathway in A. take. Received: June 3, 2002 / Accepted: July 25, 2002     

Functional properties of antigen-specific T cells infected by human T-cell leukemia-lymphoma virus (HTLV-I)

Tetanus-toxoid specific helper-inducer T-cell clones, which had been infected and transformed by human T-cell leukemia-lymphoma virus (HTLV-I), were obtained from an antigen-specific human T cell line by using a limiting dilution technique in the presence of the virus. These HTLV-I-infected T-cell clones proliferated specifically in response to soluble tetanus toxoid but, unlike normal T cells, they could do so in the absence of accessory cells. The HTLV-I-infected T-cell clones did not present the antigen to autologous antigen-specific T cells that were not infected with HTLV-I. The capacity of helper-inducer T cells to retain antigen-specific reactivity after infection by HTLV-I, while losing the normal T-cell requirement for accessory cells, has clinical and theoretical implications.     

Role for piRNAs and noncoding RNA in de novo DNA methylation of the imprinted mouse Rasgrf1 locus

Genomic imprinting causes parental origin-specific monoallelic gene expression through differential DNA methylation established in the parental germ line. However, the mechanisms underlying how specific sequences are selectively methylated are not fully understood. We have found that the components of the PIWI-interacting RNA (piRNA) pathway are required for de novo methylation of the differentially methylated region (DMR) of the imprinted mouse Rasgrf1 locus, but not other paternally imprinted loci. A retrotransposon sequence within a noncoding RNA spanning the DMR was targeted by piRNAs generated from a different locus. A direct repeat in the DMR, which is required for the methylation and imprinting of Rasgrf1, served as a promoter for this RNA. We propose a model in which piRNAs and a target RNA direct the sequence-specific methylation of Rasgrf1.     

Measurement of canine blood microparticles by flow cytometry: effect of anticoagulants and staining reagents

Microparticles (MPs) are released from budding plasma membranes into body fluids. The use of flow cytometry for the measurement of MP in canines has not been standardized. In this fundamental study, we compared the effect of anticoagulant agents, such as acid-citrate-dextrose (ACD) and heparin on the measurement of canine MPs in platelet-free plasma (PFP) using flow cytometry. In addition, we used annexin V, carboxyfluorescein succinimidyl ester (CFSE), or calcein tetraacetoxymethyl ester (calcein-AM), and explored the characteristics of the staining reagents in MP detection using flow cytometry. We were able to measure canine MPs in PFP prepared from ACD-anticoagulated blood using flow cytometry, in which the highest positive rate for fluorescent staining was observed when CFSE was used.     

Changes in Volatile Compounds of Dark and Ordinary Muscles of Yellowtail (Seriola quinqueradiata) During Short-Term Cold Storage

ABSTRACT

Changes in volatile compounds in dark and ordinary muscle of yellowtail during 2 days of refrigerated storage at 5°C were investigated. Twenty-seven compounds were identified in ordinary muscle and 39 in dark muscle during 2 days of storage at 5°C. Thirteen compounds at Day 0 of storage and 29 compounds at Day 2—such as 2,3-pentadione, 1-penten-3-ol, (Z)-2-penten-1-ol, and (E,Z)-2,4-heptadienal—identified in the dark muscle showed significantly higher values compared to ordinary muscle. Levels of thiobarbituric acid-reactive substances (TBARS) in dark muscle were significantly higher than those in ordinary muscle throughout 2 days of storage period, and a significant increase in TBARS occurred in just dark muscle at Day 2 of storage. In ordinary muscle, viable cells remained at the same order of magnitude as their initial values for 2 days. Eight aldehydes in ordinary muscle and 25 volatile compounds in dark muscle increased significantly without microbial action prior to increase in TBARS during short-term cold storage. Principal component analysis of the volatile compounds in dark and ordinary muscle was able to differentiate between different storage time samples of same muscle type as well as different muscle samples of same storage time.     

Age-associated changes of flash visual evoked potentials in dogs

Age-associated changes of visual evoked potentials by flash stimulation (flash VEP) were evaluated in 53 beagle dogs aged from 1- to 15-year-old. Among the components of flash VEP consisted of 3 positive (P1, P2 and P3) and 2 negative (N1 and N2) peaks by 150 msec, the latency of P2 and the later peaks (N2 and P3) were significantly delayed with aging. Both amplitudes of the P2-N2 and N2-P3 also showed a significant correlation with aging. The flash VEP is considered to be an available and useful technique to evaluate not only for visual pathway, but also some disturbance of neurological functions, like as those reported in demented human.     

Changes of magnetic resonance imaging on the brain in beagle dogs with aging

Age-associated changes of magnetic resonance imaging (MRI) on the brain were evaluated in 19 beagle dogs aged from 8-month- to 16-year-old. A significant correlation of the volume of lateral ventricle space was observed in the dogs with age advanced, however, no correlation was found between hippocampus size and the aging. The hypo-intensity areas on T2-weighted MRI were detected in globus pallidus and substantia nigra with a significant correlation of both intensity ratios to lateral ventricle with age advanced. These areas were coincided with the accumulation of iron in the slice of the brain with Perls' staining. In addition, hyper-intensity area, suggesting perivascular demyelination with fluid-filled space, was also observed in white matter surrounding the lateral ventricle on T2-weighted MRI. These results suggested that age-associated changes of T2-weighted MRI were developed in the dog brain, especially in globus pallidus, substantia nigra, and white matter surrounding lateral ventricle, like as those reported in the human brain.     

Quantification of lipophilic toxins associated with diarrhetic shellfish poisoning in Japanese bivalves by liquid chromatography-mass spectrometry and comparison with mouse bioassay

ABSTRACT:   Quantification of lipophilic toxins in bivalves associated with diarrhetic shellfish poisoning was investigated by liquid chromatography–mass spectrometry (LC–MS). Using a C8-silica reversed phase column and a mobile phase of aqueous acetonitrile containing 2 mM ammonium formate and 50 mM formic acid, okadaic acid, dinophysistoxin-1, 7- O -palmitoyldinophysistoxin-1, pectenotoxin-1, pectenotoxin-2, pectenotoxin-6, pectenotoxin-2 seco-acid, yessotoxin, and 45-hydroxyyessotoxin in bivalves were quantified by LC–MS in the negative mode. When the crude 90% methanol extracts were analyzed by LC–MS, there were no significant effects from bivalve matrices on the quantification of toxins. More than 200 bivalve samples collected from various production areas in Japan were analyzed by LC–MS. Pectenotoxin-6 and dinophysistoxin-1 were the dominant toxins in scallops and mussels, respectively. Yessotoxin and 45-hydroxyyessotoxin were also detected in both species. Comparison of the quantitative results obtained for these bivalve samples between LC–MS and mouse bioassay indicates that LC–MS is suitable for routine monitoring of lipophilic toxins in Japanese bivalves.