Artificial burrow preference by the Japanese crayfish Cambaroides japonicus

SUMMARY: Preference for artificial burrows by the endangered Japanese crayfish species Cambaroides japonicus was studied to improve its cultivation. The occupation of artificial burrows, which were made from straight polyvinyl chloride pipes of different internal diameters ( Y , mm), by crayfishes of different total lengths ( X , mm) was significantly ( P < 0.001, n = 56) described by a linear regression: Y = 0.49 X + 3.42 (19.0 ≤ X ≤ 70.2). Among burrows of different lengths [crayfish total length (TL) × 1, × 2, × 3, and × 4], crayfishes significantly preferred burrows that were greater than TL × 3 ( P < 0.001, n = 588).     

Ultrastructural Localization of Hydrogen Peroxide in Host Leaves Treated with AK-toxin I Produced by Alternaria alternata Japanese Pear Pathotype

The rapid generation of reactive oxygen species (ROS), called the oxidative burst, is one of the earliest host responses to pathogen infection or elicitor treatments. Therefore, we looked for the induction of ROS generation in Japanese pear leaves by the host-specific toxin, AK-toxin I using a cytochemical method for detecting H₂O₂. A small amount of non-specific generation of H₂O₂ was found in the cell walls in toxin- and water-treated susceptible and resistant leaves. Thus, the generation of H₂O₂ at cell walls appears to be caused by wounding stress during sampling. Specific generation of ROS, however, was found only in the membrane fragments and extended desmotubules characteristic of modified sites of the plasma membrane in the toxin-treated susceptible leaves. In addition, generation of H₂O₂ at plasma membranes was observed with higher frequency in toxin-treated susceptible leaves. This result indicates that the H₂O₂ generation was associated with damaged sites in the plasmalemma after toxin treatment and perhaps with the formation of membrane fragments from altered portions of the invaginated plasma membrane. Received 21 September 2001/ Accepted in revised form 25 October 2001     

Lipid-rich bovine serum albumin improves the viability and hatching ability of porcine blastocysts produced in vitro

The effects of lipid-rich bovine serum albumin (LR-BSA) on the development of porcine blastocysts produced in vitro were examined. Addition of 0.5 to 5 mg/ml LR-BSA to porcine blastocyst medium (PBM) from Day 5 (Day 0 = in vitro fertilization) significantly increased the hatching rates of blastocysts on Day 7 and the total cell numbers in Day-7 blastocysts. When Day-5 blastocysts were cultured with PBM alone, PBM containing LR-BSA, recombinant human serum albumin or fatty acid-free BSA, addition of LR-BSA significantly enhanced hatching rates and the cell number in blastocysts that survived compared with other treatments. The diameter, ATP content and numbers of both inner cell mass and total cells in Day-6 and Day-7 blastocysts cultured with PBM containing LR-BSA were significantly higher than in blastocysts cultured with PBM alone, whereas LR-BSA had no effect on mitochondrial membrane potential. The mRNA levels of enzymes involved in fatty acid metabolism and β-oxidation (ACSL1, ACSL3, CPT1, CPT2 and KAT) in Day-7 blastocysts were significantly upregulated by the addition of LR-BSA. The results indicated that LR-BSA enhanced hatching ability and quality of porcine blastocysts produced in vitro, as determined by ATP content, blastocyst diameter and expression levels of the specific genes, suggesting that the stimulatory effects of LR-BSA arise from lipids bound to albumin.     

Single oral β-cryptoxanthin administration increases its serum concentration and enhances peripheral blood neutrophil function in Holstein cattle

We investigated the effect of oral administration of β-cryptoxanthin (β-CRX) on its serum concentration and peripheral neutrophil functions by the chemiluminescence (CL) response in Holstein cattle. A single oral administration of β-CRX was performed for serum β-CRX concentration (0, 0.05, 0.1, or 0.2 mg/kg body weight [BW]) and for peak CL response of peripheral neutrophils (0.2 mg/kg BW). The serum β-CRX concentration was peaked on 2 days after, similar to peak CL response on 3 days after β-CRX administration. Therefore, a single oral administration of β-CRX (0.2 mg/kg BW) induces higher serum concentration and concurrently enhances bactericidal ability of peripheral neutrophils in Holstein cattle.     

Role of NF-kappaB in constitutive expression of MAIL in epidermal keratinocytes

Molecule possessing ankyrin-repeats induced by lipopolysaccharide (MAIL) is a nuclear IkappaB protein that is also known as interleukin-1-inducible nuclear ankyrin repeat protein and inhibitor of nuclear factor kappaBzeta (IkappaBzeta). We previously observed that MAIL-deficient mice were affected by atopic dermatitis-like skin lesions and demonstrated the importance of MAIL in the skin. In this study, we investigated MAIL expression in mouse keratinocytes. MAIL mRNA was constitutively expressed in the skin epidermis. MAIL expression was also confirmed in primary keratinocytes and the PAM212 keratinocyte cell line. The inhibitors of nuclear factor kappaB (NF-kappaB)-Bay11-7082 and the IkappaBalphaM supersuppressor-considerably downregulated MAIL expression in the keratinocytes. Immunoreactivity for NF-kappaB components was localized in the cytoplasm and nucleus of normal unstimulated keratinocytes. The expression level of MAIL in the skin did not change following lipopolysaccharide (LPS) administration to mice. Interestingly, in accordance with the in vivo findings, the MAIL expression level did not change following LPS stimulation even in primary keratinocytes; however, MAIL expression was strongly increased by interleukin-1 stimulation. These results collectively suggest that the constitutive expression of MAIL in keratinocytes is controlled, at least in part, by NF-kappaB and that there may be LPS-specific repressive mechanisms that inhibit MAIL induction.     

Effects of 3-methyl-4-nitrophenol in diesel exhaust particles on the regulation of reproductive function in immature female Japanese quail (Coturnix japonica)

In a previous study, we found that 3-methyl-4-nitrophenol (PNMC), a component of diesel exhaust particles and also a degradation product of the insecticide fenitrothion, exhibits reproductive toxicity in the adult male Japanese quail. The present study investigated the toxicity of PNMC in the female Japanese quail and its ability to influence reproduction in immature females. The quail (21-day-old) were injected intramuscularly (im) with PNMC at doses 0.1, 1 or 10 mg/kg body weight daily for 3 days. There was no significant difference in body growth between the PNMC-administered and control birds. However, the weights of the oviducts were significantly lower in the PNMC-treated birds at all doses. Furthermore, the plasma concentrations of luteinizing hormone (LH) and estradiol-17 beta were significantly decreased with 1 and 10 mg/kg of PNMC. These findings suggest that PNMC might influence the hypothalamo-pituitary-gonadal axis with decreasing in secretion of GnRH, LH and ovarian steroid hormones and subsequently disturb growth of the reproductive organs of immature female quail. This study indicates that PNMC induces reproductive toxicity at the central level and disrupts reproductive function in the immature female quail.     

Direct effects of prolactin on adrenal steroid release in male Hatano high-avoidance (HAA) rats may be mediated through Janus kinase 2 (Jak2) activity

Prolactin (PRL) has been proposed to directly stimulate corticosterone release. However, the role of PRL on adrenocortical function in male HAA rats has not been fully clarified. The aim of this study was to investigate the effect of PRL on the secretion of corticosterone and progesterone using an in vitro cell culture system in male rats. Administration of PRL (10(-7) and 10(-6) M) resulted in dose-dependent increases in corticosterone and progesterone release. Cotreatment with PRL produced an increase in the stimulatory effects of ACTH-induced corticosterone and progesterone secretion. However, the PRL-induced corticosterone and progesterone releases were significantly reduced by treatment with AG490, a specific Janus kinase 2 (Jak2) inhibitor. In addition, administration of AG490 blunted the significant inhibition of ACTH-induced corticosterone and progesterone secretion by PRL. These results demonstrated that PRL could act directly on the adrenal gland to drive corticosterone and progesterone secretion in male rats. Additionally, the results emphasize that PRL stimulation of adrenal steroid release may be mediated through Jak2 activity.     

Assessment of fertility and reproductive toxicity in adult female mice after long-term exposure to Pueraria mirifica herb

The present study investigated the effects of long-term administration of Pueraria mirifica (PM) at non-toxic doses on the ovarian function and fertility of adult female mice based on evaluation of hematological and biochemical parameters. Female mice were divided into 4 groups (36 mice/group). Groups 1-3 were orally treated with a dose of 0 (PM-0), 10 (PM-10) or 100 mg/kg BW/day PM (PM-100), and group 4 was subcutaneously injected with 200 mug/kg BW/day of synthetic estrogen diethylstilbestrol (DES). The treatment schedule was separated into treatment and post-treatment periods. The duration of each period was 8 weeks. The PM-10 mice exhibited regular estrous cycles, while the PM-100 and DES treatments induced prolonged estrous cycles. Although no changes were observed in the uterus and ovary weights of the mice after the PM-100 and DES treatments, hyperplasia of the uterine endothelium and a decrease in the number of growing ovarian follicles were detected. The changes in the ovarian histologies of the PM-100 and DES mice were related to reductions in the levels of LH and FSH, which subsequently caused a decrease in mating efficiency. Once the PM mice were able to copulate, they were capable of successfully becoming pregnant and mothering offspring. No abnormalities were observed in the external morphologies and reproductive organ weights of the 50-day-old offspring. In conclusion, our results suggest that long-term exposure to 100 mg/kg BW of PM has adverse effects on the mating efficiency and reproduction of adult female mice and that administration of 10 mg/kg BW of PM does not induce any changes in the hypothalamic-pituitary-ovarian-uterine axis.