Effect of progesterone on ovulation in the hypophysectomised hen

1. One hundred and seven laying hens were hypophysec‐tomised to clarify the relationship between hypophysectomy and the effect of progesterone (P4) on ovulation.

2. Hens were hypophysectomised at 6 intervals from 4.5 to 11.0 h before the expected time of ovulation. Ovulation occurred in the hens operated on from 4.5 to 7.3 h, but did not take place in birds operated on from 9.2 to 9.8 h before the expected time of ovulation.

3. When a single dose of P4 (2 mg/hen) was injected iv immediately after the removal of the anterior pituitary from 7.5 to 9.8 h before the expected time of ovulation, ovulation was induced. However, the percentage of hens responding decreased in proportion to the lapse of time between the hypophysectomy and the expected time of ovulation. No ovulation was induced in hens which were hypophysectomized and given P4 10.2 to 11.0 h before the expected time of ovulation.

4. It is suggested that ovulation is induced by P4 alone possibly in the absence of preovulatory gonadotrophins and that P4 acts directly on the ovary to induce follicle rupture.     

Antihyaluronidase action of ellagic acid effectively prevents polyspermy as a result of suppression of the acrosome reaction induced by sperm-zona interaction during in vitro fertilization of porcine oocytes

The present study was conducted to examine the effects of three tannin relatives (tannic acid, TA; gallic acid, GA; and ellagic acid, EA) on antihyaluronidase and reactive oxygen species (ROS) scavenging activity, in vitro fertilization (IVF) parameters, and the acrosome reaction (AR) induced by sperm-zona interaction. Among the three tannin relatives, TA and EA showed the strongest potency for blocking the hyaluronidase activity of boar sperm, with concentration-dependent inhibition over the range of 2-10 microg/ml. In contrast, ROSs were effectively scavenged by TA and GA, but not EA. When cumulus-free oocytes were inseminated in IVF medium containing 5 microg/ml of the tannin relatives, polyspermy was significantly reduced by TA and EA (32 and 29%, respectively) compared with oocytes treated with or without GA (51 and 69%, respectively) under conditions that maintained a high sperm penetration rate (P<0.05). Interestingly, induction of the AR by treatment of preincubated sperm with progesterone was blocked by TA and GA as a result of their higher levels of ROS scavenging activity, while EA, which possessed weak ROS scavenging activity, did not disturb induction of the AR with progesterone. However, the incidence of AR induced by sperm-zona interaction was significantly decreased by the strong antihyaluronidase actions of TA and EA compared with that in the absence of these compounds. Treatment with the compounds caused neither a protective proteolytic modification of the zona pellucida matrix before fertilization nor a reduction in acrosomal proteolytic activity or the number of zona-bound sperm. These findings suggest that the antihyaluronidase action of EA effectively prevents polyspermy by suppression of AR functionality induced by sperm-zona interaction and that hyaluronidase intervention is therefore required during porcine IVF.     

Susceptibility of Commercial Tomato Cultivars to Bacterial Wilt in Hydroponic System

Commercially available tomato cultivars were hydroponically cultured for inoculation, with Ralstonia solanacearum (K-101), which causes bacterial wilt, by pouring an inoculum suspension into the nutrient solution. Cultivar susceptibility to the bacteria was evaluated, based on the highest percentage of wilting. Because the length of time for wilt appearance varied among cultivars, some cultivars appeared to be suppressive to the translocation and/or multiplication of the invading pathogen. Thus, this hydroponic inoculation system is effective for examining levels of susceptibility in tomato cultivars to bacterial wilt. Received 13 December 2000/ Accepted in revised form 27 March 2001     

Clinical response of ovarian cysts in dairy cows after PRID treatment

We investigated the therapeutic effects of a progesterone releasing intravaginal device (PRID) on cystic ovarian disease (COD) and reproduction performance of cows. The possible influence of PRID on metabolic and/or health status was also examined. A total of 40 Holstein-Friesian cattle, with ovarian cystic structures, > or =2.5 cm in diameter, persisting for more than 7-14 days, without a corpus luteum (CL) were used for the study. PRID or placebos were inserted into the vagina for 12 days. Five animals lost the intravaginal device before removal and one was culled. Based on plasma progesterone concentration on the day of treatment, 20 (17 PRID and 3 placebos) of the remaining 34 cows had follicular cysts (progesterone < or =1 ng/ml) and 14 (10 PRID and 4 placebos) had luteal cysts (progesterone >1 ng/m l). Fourteen (82%) of the PRID-treated follicular cystic cows responded with formation of a CL within 14 days after treatment, and an overall conception rate of 53.8%. Likewise, 70% of the treated luteal cystic cows responded with CL formation and 71.4% conception rate. No significant differences were observed in hematocrit (Ht), white blood cell count and serum levels of glucose, blood urea nitrogen, aspartate aminotransferase, and alanine aminotransferase, between the day of PRID insertion and removal, in animals with follicular and luteal cysts. PRID treatment resulted in ovulation 2-4 days later and formation of a CL in cows that recovered.     

Percutaneous ultrasound-guided over-the-wire catheterization of the portal and hepatic vessels in cattle

A new method for catheterization of the portal and hepatic veins in cattle by means of the over-the-wire system was investigated to maintain more reliable long-term patency of catheters. Four cattle were used to evaluate the success rate, patency and safety of the procedure. The catheters, coated by urokinase were patent as long as they were in situ. In addition, the introducer was useful to prevent the catheter from being broken. No complications developed during the10 days after the procedure. Two cows were then euthanized. Post mortem findings were minimal. The results of the study reported here are promising, the benefits are significant and there is no apparent disadvantage to its use.     

Changes in concentrations of plasma immunoreactive follicle-stimulating hormone, luteinizing hormone, estradiol-17beta, testosterone, progesterone, and inhibin in heifers from birth to puberty

This study was designed to clarify the characteristics of changes in plasma concentrations of reproductive hormones in heifers from birth to puberty. Weekly or daily hormonal changes were observed in 39 heifers. Daily changes in the concentration of follicle-stimulating hormone (FSH) demonstrated a consistent cycle of hormone changes over a 7- to 8-day period in heifers from approximately 10 days to 9 months old. Weekly changes in reproductive hormones showed that there were three brief periods in heifers between birth and puberty in which dramatic changes occur. The first period was the first week after birth, during which a reciprocal relationship between steroid hormones and gonadotropins was observed. At birth, the concentrations of steroid hormones were higher than those at any other age. These hormone levels rapidly decreased within the first week after birth. Gonadotropin levels, however, increased from birth to 1 week of age. The second period of major change was at approximately 4 weeks of age when there was an increase in the concentrations of luteinizing hormone (LH), estradiol-17beta, testosterone, and immunoreactive inhibin. The third period was the last 5 weeks before the first ovulation, when there was an increase in the concentrations of estradiol-17beta followed by an increase in (LH). These results suggest that regular hormone changes start from 10 days after birth and that the periods from birth to 4 weeks of age and the last 5 weeks before the first ovulation in heifers are important to the development of reproductive functions before puberty.     

Seedborne fungi detected on stored solanaceous berry seeds and their biological activities

We isolated 629 fungi from 1296 berry seeds of solanaceous plants, including tomato (Lycopersicon esculentum), eggplant (Solanum melongena), bell pepper (Capsicum annuum), and red pepper (Capsicum annuum var. annuum) preserved for long and short terms. The isolates were classified into 22 genera excluding unidentified fungi, and the fungal floras were divided into two types: the tomato–eggplant and pepper groups. The results of cluster analysis with unweighted pair-group method with arithmetic average also supported these groups. Most tomato seeds infested with Geotrichum candidum germinated and grew the same as uninfested seeds. Cladosporium sphaerospermum and Arthrinium sp. isolated from eggplant seeds strongly suppressed germination, and Penicillium variabile suppressed seminal root elongation on eggplant. Alternaria alternata, Botrytis cinerea, and Myrothecium verrucaria detected from red pepper or bell pepper seeds were pathogenic to the fruits and the seedlings after artificial inoculation.     

Soft X-ray observation of water distribution in the stem ofCryptomeria japonica D. Don II: Types found in wet-area distribution patterns in transverse sections of the stem

Using soft X-ray photography, two-dimensional observations were made of the water distribution within the green stem ofCryptomeria japonica D. Don. Variations in the distribution pattern of the wet area in the horizontal plane of the lower stem were described. The distribution patterns showed extreme variation among individual trees, with broad wet-area distribution types appearing, namely, the regularly distributed wet area and the irregularly distributed wet area. We defined five basic types of wet-area distribution patterns on the basis of their regularity or irregularity. It was concluded that the between-tree variation in the wet-area distribution causes the between-tree variation in the mean moisture content of the heartwood. The distribution patterns of the wet area were similar for individual trees within each plus-tree clone.Part of this paper was presented at 46th annual meeting of the Japan Wood Research Society at Kumamoto, April 1996