Preliminary studies of the effects of bromocriptine on testicular regression and the spring moult in a seasonal breeder, the male blue fox (Alopex lagopus)

Bromocriptine administration in the form of slow-release injections to male blue foxes during March-May abolished the normal spring rise in plasma prolactin concentrations seen in May and June. The spring moult was prevented and the treated animals retained a winter coat of varied quality and maturity until the end of the study in August. Plasma testosterone concentrations fell normally from March until August. Testicular regression was, however, delayed, although there were individual variations in response. Estimation by DNA flow cytometry in early July of the relative numbers of haploid, diploid and tetraploid cells in the testis showed that, in the treated animals, 74-80% of the cells were haploid (maturing germinal cells), 4-6% tetraploid (mainly primary spermatocytes) and the rest diploid cells (somatic cells and the remaining germinal cell types). In the control males, however, no haploid cells were detected and the majority of cells were diploid (93-99%). At castration in August, histological examination revealed various stages of testicular regression in the treated and control animals.     

Electron microscopical studies of membrane injuries in blue fox spermatozoa subjected to the process of freezing and thawing

Disintegration of blue fox sperm membranes is studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In unfrozen spermatozoa studied by SEM, the plasmalemma and the acrosome appeared to be intact, except for a few cases of disruption of the former structure at the anterior part of the head. In semen frozen in 0.5-ml plastic straws by use of N2 vapor after dilution with Tris-fructose-citric acid with 8 vol % glycerol and 20 vol % egg yolk and thawed at 70 degrees C for 8 sec, the spermatozoa displayed different degrees of membrane damage. These alterations could be classified into three main categories of which the first included only minor changes in the plasmalemma, but vesiculation and disintegration of the outer part of the acrosomal membrane. In the second category (also the most frequent one) the outer part of the acrosomal membrane was extensively vesiculated, and the plasmalemma was discharged proximal to the equatorial segment. Extensive loss of plasmalemma and complete absence of the outer part of the acrosomal membrane characterized the last category of membrane damage. The functional implications of the three categories of membrane alterations are discussed.     

Synthetic glycolipid-based TLR4 antagonists negatively regulate TRIF-dependent TLR4 signalling in human macrophages

TLRs, including TLR4, play a crucial role in inflammatory-based diseases, and TLR4 has been identified as a therapeutic target for pharmacological intervention. In previous studies, we investigated the potential of FP7, a novel synthetic glycolipid active as a TLR4 antagonist, to inhibit haematopoietic and non-haematopoietic MyD88-dependent TLR4 pro-inflammatory signalling. The main aim of this study was to investigate the action of FP7 and its derivative FP12 on MyD88-independent TLR4 signalling in THP-1 derived macrophages. Western blotting, Ab array and ELISA approaches were used to explore the effect of FP7 and FP12 on TRIF-dependent TLR4 functional activity in response to LPS and other endogenous TLR4 ligands in THP-1 macrophages. A different kinetic in the inhibition of endotoxin-driven TBK1, IRF3 and STAT1 phosphorylation was observed using different LPS chemotypes. Following activation of TLR4 by LPS, data revealed that FP7 and FP12 inhibited TBK1, IRF3 and STAT1 phosphorylation which was associated with down-regulation IFN-β and IP-10. Specific blockage of the IFN type one receptor showed that these novel molecules inhibited TRIF-dependent TLR4 signalling via IFN-β pathways. These results add novel information on the mechanism of action of monosaccharide FP derivatives. The inhibition of the TRIF-dependent pathway in human macrophages suggests potential therapeutic uses for these novel TLR4 antagonists in pharmacological interventions on inflammatory diseases.     

The importance of farrowing to service interval in sows served during lactation or after shorter lactation than 28 days

In a retrospective study, based on data from the national litter recording system, farrowing rate and litter size of sows served (inseminated or mated) during the lactation period (n = 574) or after a lactation period shorter than 28 days (n = 14,219) were analysed. The results were compared with the corresponding figures for sows with lactation length between 28 and 35 days and weaning to first service interval of 4 or 5 days (reference group; n = 41,741). The farrowing rate of the reference group was 80.9% and subsequent litter size was 13.7 total piglets born. Among sows served prior to weaning, the farrowing rates and litter sizes were significantly lower for those served earlier than 22 days post-farrowing compared to those served later (P < 0.05). Shorter lactations than 28 days and service within 10 days post-weaning led to lower farrowing rates than in the reference group (P < 0.01). Significant differences were seen after different lactation lengths. After correction for weaning to service interval, preceding litter size weaned, parity, breed and the interaction between parity and breed, litter size was significantly and positively associated with the preceding lactation length. The study shows that service within the first 3 weeks post-farrowing results in reduced reproductive performance.     

Resistance of tomato infected with cucumber mosaic virus satellite RNA to potato spindle tuber viroid

Tomato (Lycopersicon esculentum cvs Rutgers and Lichun) plants were firstly pre-inoculated either with a cucumber mosaic virus (CMV) isolate containing satellite RNA (CMV-S52) or with a CMV isolate without satellite RNA, and then challenged 14 days later with a severe strain of potato spindle tuber viroid (PSTVd). Also, tomato plants transformed with CMV satellite cDNA and non-transgenic control plants were directly inoculated with PSTVd. Protection effects were assessed by the observation of symptoms and by assay of PSTVd accumulation in tomato plants using return polyacrylamide gel electrophoresis and silver staining. The results indicated that the satellite-transgenic plants and plants pre-inoculated with CMV-S52 showed much milder symptoms of PSTVd infection than the respective control plants. The concentration of PSTVd RNA in the satellite-transgenic plants and CMV-S52 pre-inoculated plants was reduced to about 0.02-0.03 of the controls. PSTVd infection did not increase the amount of satellite ds-RNA in plants. It is concluded that the plant resistance to PSTVd is induced by the presence of satellite RNA rather than the CMV infection. It is suggested that as there is considerable sequence similarity between satellite RNA and PSTVd, base pairings may be a cause of reduction of both symptoms and the accumulation of PSTVd.     

Photoperiodic regulation of reproduction in the male silver fox (Vulpes vulpes)

Six silver fox males were exposed to short days (6L:18D) from February, when the testes were fully developed, until June 1986 (Group 6L). Eight males maintained in natural daylight served as controls (Group N). Histological sections from the testes of 2 males in Group 6L killed in June indicated full spermatogenic activity. Three blue fox vixens inseminated the following year with semen collected and frozen in June from 3 males in Group 6L failed to produce litters. One possible explanation for the reproductive failures could have been that the high environmental temperatures in June influenced semen quality. There was no significant difference (P greater than 0.05) in LH release in response to GnRH stimulation in June, but testosterone response to LH release was significantly higher (P less than 0.01) in animals subjected to a restricted photoperiod, demonstrating that testicular testosterone production was maintained longer than in control animals. Two males in Group 6L were retained in 6L:18D from June until December 1986 and then exposed to natural daylight until the end of the study in May 1987 (Group 6L:6L:N). These males started to shed their winter coat and showed clinical signs of testicular regression in December, i.e. after approximately 11 months exposure to 6L:18D. The 2 remaining males in Group 6L were moved to cages with natural daylight in June 1986, where they were kept until the end of the experiment (Group 6L: N:N). These males displayed testicular regression soon after the change in photoperiod but maintained their capacity for testicular redevelopment during the following breeding season.(ABSTRACT TRUNCATED AT 250 WORDS)     

情前期与间情期大鼠内侧视前区-下丘脑前区神经元的电活动

在氯化筒箭毒制动的情前期及间情期大鼠上进行实验。用玻璃微电极记录内侧视前区-下丘脑前区(mPOA-AHA)的单位放电。mPOA-AHA 的大多数单位表现连续性或周期性自发放电。情前期大鼠周期性放电单位所占的百分比显著地多于间情期大鼠(P<0.01)。刺激子宫颈部可以使单位放电发生两种反应。一种单位对宫颈刺激发生放电频率增加的反应(宫颈兴奋神经元,CE 神经元),另一种单位则发生放电频率降低的反应(宫颈抑制神经元,CI神经元)。情前期大鼠 CE 与 CI 神经元所占的百分比与间情期大鼠没有明显的差异(P>0.05)。但情前期大鼠的 CE和 CI 神经元多呈现周期性放电,而间情期大鼠的 CE 和 CI 神经元则多呈现连续性放电。这说明 mPOA-AHA 神经元的电活动随生殖周期发生明显的变化。脑室注射去甲肾上腺素(NE)能使 mPOA-AHA 内大多数 CE 神经元对宫颈刺激的兴奋反应暂时受到抑制,而注射 NE 却使大多数 CI 神经元发生抑制解除。这些结果提示 NE 可能有抑制 CE 神经元和刺激 CI 神经元的作用。     

The Plant Cell Surface

Multicellular organization and tissue construction has evolved along essentially different lines in plants and animals. Since plants do not run away, but are anchored in the soil, their tissues are more or less firm and stiff. This strength stems     

Effects of in vitro storage time and semen-extender on membrane quality of boar sperm assessed by flow cytometry

The Norwegian AI company Norsvin has used the short-term semen-extender BTS to extend and store boar semen since the late 1980s. Fertility results have been consistent when extended semen has been used for AI within 3 days after collection, however, from a production and economic point of view it is preferable that semen stored for up to 5 days can be used. The aim of this study was to compare membrane quality of sperm stored in BTS for 3 days with sperm stored in the long-term semen-extenders Androstar, Mulberry III and X-cell for 5 days. Using a split-sample design, plasma membrane- and acrosome-integrity were assessed flow cytometrically by use of Yo-Pro-1 and PNA-FITC, and fluidity and phospholipid asymmetry of the membrane were assessed by use of MC540 and Annexin V-FITC. Due to observed sperm fragmentation in Androstar after Day 1, the data for Androstar were excluded from the analyses. After 5 days of storage, the membrane quality of X-cell-stored sperm was not statistically different from that of sperm stored in BTS for 3 days, while membrane quality of sperm stored in Mulberry III was statistically better on Day 5 compared to BTS on Day 3. In conclusion, Mulberry III and X-cell preserve sperm quality, as well as that of BTS on Day 3, for up to 5 days after collection.