Immunoreactive changes in pituitary FSH and LH cells during seasonal reproductive and spawning cycles of female chub mackerel <Emphasis Type="Italic">Scomber japonicus</Emphasis>

The physiological functions of pituitary gonadotropins (GtHs) are well established in higher vertebrates, whereas those in teleosts are still poorly understood. To describe the role of GtHs during gonadal development of female chub mackerel Scomber japonicus, changes in follicle-stimulating hormone (FSH) and luteinizing hormone (LH) cells were investigated immunohistochemically during the seasonal reproductive and spawning cycles. FSH and LH cells were identified in the different cell types of the proximal pars distalis (PPD); FSH cells were located in the central PPD, whereas LH cells were localized along the border of the pars intermedia. To examine changes in FSH and LH cells, the percentage of FSH or LH cell-occupying area in the PPD was evaluated and represented as FSHβ-immunoreactive (ir) or LHβ-ir levels, respectively. FSHβ-ir levels increased significantly from immature to the completion of vitellogenesis, whereas LHβ-ir levels were maintained at high levels from early vitellogenesis to post-spawning. During the spawning cycle, which consisted of four stages from just after spawning to the next oocyte maturation, both FSHβ-ir and LHβ-ir levels showed no significant changes among different stages; however, LHβ-ir levels remained relatively high, and FSHβ-ir levels were constantly low. These results suggest that both FSH and LH may be involved in vitellogenesis and LH may act at final oocyte maturation in female chub mackerel, although the role of FSH during the spawning cycle is still unclear.     

Hydrothermal Treatment of Date Palm Lignocellulose Residue for Organic Fertilizer Conversion: Effect on Cell Wall and Aerobic Degradation Rate

Date palm (Phoenix roebelenii) woodchips, a residue of palm tree plantations, was subjected to hydrothermal treatment (HTT) at mild reaction conditions (160°C < T < 220°C, 0.6 MPa < P < 2.4 MPa) for 30 min, and the effect of treatments on the cell wall (CW) solubilization and subsequent aerobic degradation rate (as CO production) was tested under controlled composting conditions during 63 days of incubation (38°C). The HTT at 160 and 180°C reaction temperatures notably solubilized hemicellulose, decreasing the fraction of this CW polymer from 34.1% in the untreated material, to 9.5 and 4.6% in the respective residues. However, treatment at 200 and 220°C reaction temperatures rapidly liquefied the lignin, which apparently went into solution with hemicellulose and appeared to stabilize a portion of this polysaccharides against hydrolysis. Consequently, the fraction of hemicellulose in 200 and 220°C – treated residues gradually increased; the respective values were 5.8 and 9.4%. The treatment temperature of 180°C was the most effective HTT temperature for subsequent aerobic degradation by solubilizing the largest portion of hemicellulose within the CW, which had two consequences: 1) it supplied additional readily bioavailable form of carbon, which in turn promoted rapid microbial activities in the early stage of decomposition; and 2) it created pores and cavities within the CW, which permitted rapid bacterial penetration and CW degradation. As a consequence, biodegradation of the residue treated under this reaction temperature proceeded rapidly and stability was reached within 21 days, compared to 63 days of continued degradation for the untreated CW. The enhanced biodegradability was also partially linked to the effect of 180°C treatment temperature on solubilization of amorphous cellulose and partial hydrolysis of lignin. Based on the results, the HTT system can successfully be used as a pretreatment step to accelerate the aerobic digestion rate of date palm residues for the production of organic fertilizers.     

Age and maturation of jack mackerel Trachurus japonicus in the East China Sea

Growth and reproductive characteristics of jack mackerel Trachurus japonicus collected in the East China Sea were determined based on otolith readings and gonad histology, respectively. Translucent and opaque zones on sectioned otoliths were identified and opaque rings counted. Von Bertalanffy growth parameters did not significantly differ between males and females, and the combined growth curve was: L _t  = 401{1 ? exp[?0.275 (t + 1.149)]} (0.8 < t < 6.9), where L _t is fork length (mm) at age t. The calculated lengths at age 1 in our study were larger than those reported 50 years ago from the East China Sea. The spawning period was evaluated to be from December to June, but primarily from February to May, based on the monthly changes in the gonadosomatic index and histological observations. The minimum size and age at first maturity were smaller and younger, respectively, than those reported in previous studies.     

Comparison of two quantitative assays for xenotropic murine leukemia virus-related virus

Xenotropic murine leukemia virus-related virus (XMRV), a novel gammaretrovirus in humans, was found in patients with prostate cancer (PC) and chronic fatigue syndrome (CFS). However, there has been controversy whether XMRV is directly associated with human diseases. In this study, we developed a LacZ marker rescue assay using human embryonic kidney 293T cells and a focus assay using a feline fibroblastic sarcoma-positive leukemia-negative QN10S cells. XMRV induced prominent foci in QN10S cells and the viral titer determined by the focus assay was as high as that by the LacZ marker rescue assay. Because the focus assay is simple and sensitive, it will be useful for monitoring infectious XMRVs in CFS and PC patients and virological studies for XMRV.     

The histopathogenesis of paralytic rabies in six-week-old C57BL/6J mice following inoculation of the CVS-11 strain into the right triceps surae muscle

A fatal encephalomyelitis was developed after intracerebral and hind limb inoculation of in 6-week-old C57BL/6J mice by the inoculation of fixed rabies virus (CVS-11 strain), intracerebrally and into hind. After the intracerebral inoculation, virus antigens were detected in the cerebral cortex and hippocampus at 2 days postinoculation (PI), and later spread centrifugally to thalamus, brain stem, cerebellum, spinal cord and spinal ganglia. At 4 days PI, severe apoptosis and DNA fragmentation were observed in the hippocampus and cerebral cortex. All mice infected intracerebrally were dead without limb paralysis at from 10 to 11 days PI. In contrast, mice infected with virus intramuscularly were persistently observed virus antigens in the myocytes at the site of inoculation from 2 days PI. At 4 days PI, the antigens were demonstrated in the spinal dorsal root ganglia, spinal cord and muscle spindles without their detection in the cerebrum and hippocampus. There were no apoptosis in the spinal cord and dorsal root ganglia, however hind limb paralysis was found in all infected mice. Hind limb paralysis was progressed to quadriparalysis, and mice were dead from 11 to 13 days PI. From 4 days PI, necrosis of neuron was observed in the the spinal and dorsal ganglia with infiltration of lymphocyte. This study suggested that the necrosis of spinal neurons was more important to cause the paralysis of hind limb rather than the severe cerebral infection and apoptosis in C57BL/6J mice infected with CVS-11 strain. The virus primarily replicated in the muscles was ascended the spinal cord via afferent fibers and retrogradely invaded the cerebrum, and with subsequent spread to muscle spindles.     

Fertility of ewes inseminated intrauterinally with frozen semen using extender containing bovine serum albumin

The present study was conducted to examine the fertility of ewes inseminated intrauterinally with frozen semen using semen extender containing either egg yolk or bovine serum albumin (BSA). Sixty Suffolk and cross-bred ewes were treated with controlled internal drug release (CIDR) devices during the non-breeding season (July 2006). A CIDR was inserted into the vagina for 12 days and an intramuscular injection of 500 IU equine chorionic gonadotropin was administered one day before its removal. Ejaculates from a suffolk ram were diluted with a Tris-based extender containing either 15% (v/v) egg yolk or 10% (w/v) BSA, and the diluted semen was frozen in 0.25 ml straws. A fixed-time intrauterine artificial insemination (AI) was performed 43-47 h after CIDR removal, regardless of incidence of estrus. There was no significant difference in pregnancy rates at 60 days after AI between the extenders containing egg yolk (66.7%, 20/30 animals) or BSA (65.5%, 19/29 animals). Furthermore, there were no significant difference in the lambing rates (66.7% and 62.1%) and prolificacy (1.25 and 1.56) between the two semen extenders. The present study indicates that a semi-defined semen extender containing 10% BSA produces fertility after intrauterine AI that is similar to that achieved with semen extender containing egg yolk.     

A clinical case of severe anemia in a sheep coinfected with Mycoplasma ovis and 'Candidatus Mycoplasma haemovis' in Hokkaido, Japan

A 2-year-old East Friesian sheep imported from Australia exhibited severe anemia after contagious pustular dermatitis in Hokkaido, Japan. Hemoplasma infection was confirmed in blood smears. Both Mycoplasma ovis and 'Candidatus Mycoplasma haemovis' were detected by PCR and sequence analyses. In the epidemiological analysis, dual pathogens were detected in 6 of 12 (50.0%) sheep imported from Australia with the infected ewe at the same time, 1 of 5 (20.0%) sheep introduced from a domestic farm in Hokkaido, and in 1 of 16 (6.3%) sheep from an epidemiologically unrelated ranch. It is the first clinical case of sheep to confirm coinfection of these pathogens in Japan.     

First report of raspberry yellows disease caused by raspberry bushy dwarf virus in Japan

Severe yellowing of leaves was observed on red raspberry in Akita Prefecture. When inoculated with sap from symptomatic raspberry leaves, Chenopodium quinoa plants developed chlorotic ringspot and mottling that are typical of raspberry bushy dwarf virus (RBDV) infection. In western blot analysis, an antibody to the coat protein (CP) of RBDV reacted against ca. 30-kDa protein specific to the diseased trees. In RT-PCR testing for RBDV, single DNA fragments were amplified from total RNA samples of the diseased trees. The nucleotide sequences of the DNA fragments covering the entire CP region revealed 87–97?% identities with those of RBDV isolates.