Incidence of thiophanate-methyl resistance in Cercospora kikuchii within a single lineage based on amplified fragment length polymorphisms in Japan

We collected 247 isolates of Cercospora kikuchii from soybean seeds with typical purple stain symptoms from 15 prefectures in Japan. Of the 247 isolates, 93 were sensitive to thiophanate-methyl, a benzimidazole used to control this soybean disease; the remaining 154 were highly resistant to the fungicide. To examine genetic variability among the population of 247 isolates, we developed amplified fragment length polymorphism (AFLP) markers. An AFLP primer pair generated DNA fingerprint polymorphisms among the sample isolates, and with the unweighted pair-grouping method to cluster arithmetic means of the similarity coefficients among all pairs of the fingerprint patterns, the isolates were divided into four lineages (I to IV). Of the 247 isolates, 225 belonged to lineage I, including all isolates that were resistant to thiophanate-methyl. To determine whether the resistance of these isolates was related to mutations in the β-tubulin gene, we amplified partial nucleotide sequences of the gene from 29 representative isolates, including 12 that were resistant to thiophanate-methyl, by means of the polymerase chain reaction. The resistant isolates had identical nucleotide sequence with a one-step change at codon 198, in which the amino acid glutamic acid had been replaced by alanine. The evidence thus suggests that thiophanate-methyl resistance might have arisen in lineage I, the largest of the four lineages. The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under accession numbers AB214511 to AB214515     

Ontogenetic and diel variation in the vertical distribution of larvae of jack mackerel <Emphasis Type="Italic">Trachurus japonicus</Emphasis> in the East China sea

Larvae of jack mackerel Trachurus japonicus were sampled in seven depth layers (0–10 m, 10–20 m, 20–30 m, 30–40 m, 40–50 m, 50–70 m, and 70–100 m), with a closing-type frame net, on 26th–27th February, 2003, at Sta. V (27°50′N, 126°00′E) continental shelf edge in the southern part of East China Sea, to examine their vertical distribution. Most of the larvae (>90%) occurred in the upper 50 m layer during both day and night. In the daytime, larvae of length from 3.0 mm to 4.5 mm were most abundant in the 10–20 m layer, those from 5.0 to 6.0 mm were most abundant in the 20–30 m layer, those from 6.0 to 8.0 mm occurred at greater depth, in the 30–40 m layer, and those more than 9.0 mm were found in the 0–10 m layer and performed ontogenetic vertical migrations. Larvae from 6 mm to 8 mm length performed diurnal vertical migration, for the percentage (16.7%) of larval number in the 0–20 m layer in the daytime increased to 42.1% at night and the percentage (78.1%) in the 20–50 m layer in the daytime decreased to 49.0% at night.     

Sugar transporter (MfsX) of the major facilitator superfamily is required for flagella-mediated pathogenesis in <Emphasis Type="Italic">Dickeya dadantii</Emphasis> 3937

Dickeya dadantii (syn. Erwinia chrysanthemi) is a causal agent of soft-rot diseases on many crops. Here, we characterized a gene belonging to the major facilitator superfamily (MFS), which is involved in the symport, antiport, or uniport of various substrates, and the survival and virulence of many Gram-negative bacterial animal pathogens, for the possible involvement in the plant pathogenicity of D. dadantii. A marker-exchange mutant of this gene (mfsX) was constructed that had decreased maceration ability in Chinese cabbage, potato, and chicory. Observation with electron microscopy showed greatly reduced numbers of flagella per cell. This mutant had a significant reduction in swimming and swarming motility and a severe reduction in formation of biofilm. Because these phenotypes have been shown to be involved in plant pathogenicity of D. dadantii, mfsX seems to play an important role in pathogenesis of D. dadantii 3937 by its involvement in the expression of these pathogenicity-related phenotypes.     

Mapping of expressed sequence tag markers with a cDNA-amplified fragment length polymorphism method in Japanese quail (Coturnix japonica)

In our previous study, a Kobe‐NIBS Japanese quail (KNQ) linkage map was constructed mainly using amplified fragment length polymorphism (AFLP) markers. In order to compare chicken and quail chromosomes, we developed expressed sequence tag (EST) markers derived from cDNA‐AFLP fragments and localized these markers on the linkage map. Using a total of 128 AFLP primer combinations, 24 polymorphic bands were obtained between a neurofilament‐deficient mutant quail line male and a muscular disorder quail line female, which were the parents of the KNQ resource family. Nine of the 24 markers were mapped by linkage analysis. These markers were mapped to seven linkage groups, namely 1, 2, 3, 6, 8, 15 and 42. A subsequent homology search using chicken genome sequences strongly suggests that these linkage groups correspond with chicken chromosomes 1, 2, 3, 5, 15, 23 and 26.     

Precursor B-1 B cell lymphoma in a newborn calf.

A newborn Holstein female calf had neoplastic lesions in the skin and within the thoracic and abdominal cavities but not in the bone marrow, spleen, thymus, or most lymph nodes. Because the tumor cells were positive for CD79a (B cell marker), CD5 (B-1 cell marker) and terminal deoxynucleotidyl transferase (marker for immature lymphoid precursors), a diagnosis of precursor B-1 B cell lymphoma was made. The diagnosis was strongly supported by the fact that B-1 cells can develop in the fetus, unlike B-2 cells, which are produced after birth. The lymphoma was distinct from the typical calf form of lymphoma of B-2 cell origin, which does not express CD5 and is characterized by generalized lymphadenopathy and involvement of the bone marrow, blood and spleen.     

Pinpointing the candidate region for muscular dystrophy in chickens with an abnormal muscle gene

Muscular dystrophies, a group of inherited diseases with the progressive weakness and degeneration of skeletal muscle, contain genetically variable diseases. Though chicken muscular dystrophy with abnormal muscle (AM) has long been known, the gene responsible has not yet been identified. In this study, a resource family for AM was established with 487 F2 individuals and 22 gene markers, including microsatellite and insertion–deletion markers, were developed. The haplotypes were analyzed with these markers for the candidate region of GGA2q described in a previous study. The candidate region was successfully narrowed down to approximately 1Mbp. The region included seven functional genes predicted as the most likely AM candidates.     

Molecular phylogenetic analysis of bovine papular stomatitis viruses detected in Saga,Japan

In this study, we performed a molecular phylogenetic analysis of six bovine papular stomatitis virus (BPSV) field strains detected from Japanese beef calves kept on a farm in Saga prefecture, a southwest part of Japan, from 2017 to 2020. The phylogenetic analysis based on a partial B2L gene (554-nt) showed that these field strains were divided into two lineages, a lineage (A-lineage) constructed by a Saga strain and strains obtained from various regions of Japan and the world, and other lineage (B-lineage) constructed by five Saga strains and strains obtained from France, USA and Iwate prefecture (a north part of Japan). Furthermore, a Saga field strain named BPSV_SAGAbv2 and strains obtained from USA and Iwate prefecture belonged to a sub-lineage blanched from B-lineage. This is the first report elucidating molecular epidemiological characters of field BPSVs obtained from Saga prefecture. The existence of the multiple lineages was thought to be related to a history of calf introduction from various regions of Japan into Saga prefecture.     

The bio‐surfactant mannosylerythritol lipid acts as a selective antibacterial agent to modulate rumen fermentation

Methyl‐mannosylerythritol lipid (MEL), a new sugar esterified lipid synthesized by Pseudozyma aphidis, was assessed for its functionality in modulating rumen fermentation and microbiota toward more propionate and less methane production. A pure culture study using rumen representatives showed that MEL selectively inhibited the growth of most Gram‐positive bacteria including Streptococcus bovis, ruminococci, and Fibrobacter succinogenes, but not Gram‐negative bacteria such as Megasphaera elsdenii, Succinivibrio dextrinosolvens, and Selenomonas ruminantium. A batch culture study revealed that MEL significantly decreased methane production in a dose‐dependent manner with accumulation of hydrogen, while propionate production was enhanced. A continuous culture (Rusitec) study confirmed all of these changes. A feeding study revealed that sheep fed a MEL diet showed an increased proportion of propionate, while proportions of acetate and butyrate were decreased without affecting total VFA level. These changes disappeared after cessation of MEL feeding. Based on these results, dietary application of MEL can favorably modify rumen fermentation in terms of the efficiency of dietary energy utilization.     

Diurnal rhythm of serum steroid hormone levels in the Japanese whiting,Sillago japonica,a daily-spawning teleost

Ovarian developmental stages and serum steroid hormone levels were examined at six different times of day (0100, 0600, 1000, 1300, 1600, 2000 h) in a marine teleost, the Japanese whiting Sillago japonica, which has an asynchronous-type ovary containing oocytes at various stages of development and spawns every day during a period ranging up to three months. The largest oocytes in the ovaries at the active vitellogenic or post-vitellogenic stages were found between 0100 and 1300 h. Oocyte maturation indicated by germinal vesicle breakdown (GVBD) occurred at 1600 h, and ovulated oocytes were observed in the ovaries collected at 2000 h. These processes were accompanied by a significant daily change in serum steroid hormone levels. The serum level of estradiol-17β showed a peak in fish with mature oocytes sampled at 1600 h. In these fish, the second-largest oocytes in the ovaries were at the initial stage of vigorous vitellogenesis, the secondary yolk stage. Therefore the highest level of serum estradiol-17β was considered to be due to the second-largest oocytes. Testosterone levels remained low and constant throughout the experimental period. The serum levels of 17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-diOHprog) peaked at 1600 h at which time all fish had mature oocytes. These results indicate that the Japanese whiting possesses a diurnal rhythm of oocyte development including vitellogenesis, oocyte maturation and ovulation, and further suggest that daily cycles in oocyte growth and maturation which simultaneously take place in an ovary are regulated by diurnal secretions of estradiol-17β and the maturation-inducing steroid, 17α,20β-diOHprog.