Chronic Peripheral Administration of Kappa-Opioid Receptor Antagonist Advances Puberty Onset Associated with Acceleration of Pulsatile Luteinizing Hormone Secretion in Female Rats

Puberty in mammals is timed by an increase in gonadotropin-releasing hormone (GnRH) secretion. Previous studies have shown involvement of the two neuropeptides, kisspeptin and neurokinin B (NKB), in controlling puberty onset. Little is known about the role of the other key neuropeptide, dynorphin, in controlling puberty onset, although these three neuropeptides colocalize in the arcuate kisspeptin neurons. The arcuate kisspeptin neuron, which is also referred to as the KNDy neuron, has recently been considered to play a role as an intrinsic source of the GnRH pulse generator. The present study aimed to determine if attenuation of inhibitory dynorphin-kappa-opioid receptor (KOR) signaling triggers the initiation of puberty in normal developing female rats. The present study also determined if stimulatory NKB-neurokinin 3 receptor (NK3R) signaling advances puberty onset. Female Wistar-Imamichi rats were weaned and intraperitoneally implanted with osmotic minipumps filled with nor-binaltorphimine (nor-BNI), a KOR antagonist, or senktide, a NK3R agonist, at 20 days of age. Fourteen days of intraperitoneal infusion of nor-BNI or senktide advanced puberty onset, manifested as vaginal opening and the first vaginal estrus in female rats. Frequent blood sampling showed that nor-BNI significantly increased luteinizing hormone (LH) pulse frequency at 29 days of age compared with vehicle-treated controls. Senktide tended to increase this frequency, but its effect was not statistically significant. The present results suggest that the inhibitory input of dynorphin-KOR signaling plays a role in the prepubertal restraint of GnRH/LH secretion in normal developing female rats and that attenuation of dynorphin-KOR signaling and increase in NKB-NK3R signaling trigger the onset of puberty in female rats.     

天然青杨种群性成熟条件及性别间差异

对小五台山地区青杨种群进行野外调查和数据分析研究,发现雌雄植株的性成熟条件具有差异。雌株性成熟的最小年龄(17 a)小于雄株(21 a),而雄株性成熟时的最小胸径和株高都大于雌株,不同性别的青杨其性成熟条件存在差异,雌株性成熟时间一般早于雄株,并且其成熟时的个体也小于雄株。     

Effects of chronic heat stress on the reproductive capacity of male Rex rabbits

The effects of chronic heat stress on the reproductive system of rabbits have not been thoroughly examined. Therefore, we investigated the effects of heat stress on the reproductive performance of male Rex rabbits and documented the recovery process after stress withdrawal. Thirty age-matched, male Rex rabbits were placed into artificial climate chambers and randomly divided into three groups: control, heat stress, and recovery. Our results indicate that both libido of rabbit and sperm density were decreased significantly during the 9 weeks exposure to heat stress. Semen volume was mildly affected. Histomorphological and TUNEL assay results showed that chronic heat treatment adversely affected microscopic structure of the testes, and elevated the apoptosis of germ cells in the seminiferous tubules distinctly. However, these adverse effects induced by heat were transient as all measured parameters returned to control levels following the recovery period.     

Influence sexual dimorphism on the persistence of blood parasites in infected Calomys callosus

Gender has long been known to be a contributory factor in the incidence and progression of disorders associated with immune system disregulation. The aims of this experiment were to verify the influences of sexual dimorphism on the persistence of blood parasites out of the acute phase of infection. Male and female Calomys callosus were separated and infected with two strains of Trypanosoma cruzi, and let age until 120 days. Xenogiagnostic, culture of organs and blood, histopathology and lytic antibody percentages were evaluated on late chronic phase. Xenodiagnosis, hemoculture and lytic antibody percentages were positive from 45 until 120 days. For both strains in adrenal and heart, amastigote burdens were present until 45 days, scarcely found on 60 days and absent on 120 days. Steroid hormones, although having a protective role, does not enable animals to get completely rid of the infection. Even without showing apparent signs of pathological unbalance, parasites persists, hidden throughout the host’s body.     

性诱剂和诱捕器诱杀害虫效果简报

通过进行性诱剂和诱捕器诱杀害虫的对比试验,试验结果表明,从诱捕器的诱虫效果来看,不管是单放还是混放性诱剂均以用UMT—B诱捕器的诱蛾量较多。从性诱剂诱芯的诱虫效果来看.不管是用UMT—B诱捕器还是可乐瓶诱捕器,单放甜菜夜蛾性诱剂诱蛾量较多。从诱蛾持效期来看,中科院甜菜夜蛾诱芯诱蛾持效期较长,达30 d左右。     

刺槐无性系开花结实生殖特性及杂交亲本选配

对‘鲁刺1’(R.pseudoacacia‘Lu Ci 1’)、‘鲁刺7’(‘Lu Ci 7’)、‘鲁刺9’(‘Lu Ci 9’)、‘鲁刺57’(‘Lu Ci 57’)、‘鲁刺68’(‘Lu Ci 68’)、‘鲁刺152’(‘Lu Ci 152’)、‘兴刺1’(‘Xing Ci 1’)、‘兴刺15’(‘Xing Ci15’)、‘晋刺4’(‘Jin Ci 4’)等20个刺槐无性系的开花物候期、生殖器官形态结构、花粉活力、人工授粉结实率、杂交种子发育期及杂种发芽率等开展了试验观测研究。结果表明:刺槐无性系在鲁中南山区开花物候期为4月下旬至5月上旬,单株开花持续时间5~7 d,单朵小花开放时间为2~3 d。花粉采收后干燥24 h和低温贮藏5 d后在MS培养基上培养6~8 h,萌发率分别为22%和20%。自人工授粉至种子生长发育成熟需要80~90 d。不同无性系组合人工控制授粉结实率差异较大,平均结实率8.47%,最高为21.28%,最低为零,‘鲁刺68’、‘兴刺15’和‘晋刺4’生殖能力较强,适宜做杂交父本;‘鲁刺57’和‘鲁刺152’作母本的组合结实率较高,且杂种发芽率较高,生殖能力较强,适宜做杂交母本。杂交种子2个年度(2013年、2014年)播种发芽率分别是22%和23%,不同无性系组合发芽率差异很大,最高达50%,最低为零。     

辣木有性繁殖技术研究进展

从辣木(Moringa oleifera Lam.)的种子处理、基质筛选、栽培密度和病虫害防治4个方面综述了国内在辣木有性繁殖技术上的研究进展,并在此基础上针对一些问题进行探讨,旨在为辣木的研究与推广应用提供参考。     

虎斑颈槽蛇肾脏存在两性差异

虎斑颈槽蛇 (Rhabdophistigrina)雌、雄性的肾脏在形态和结构上存在明显的差异 ,雌性虎斑槽蛇的肾脏呈暗红色且较细小 ,雄性的肾脏呈橙黄色且较粗壮 ;雄性肾脏具有明显肾性节(Sexualsegment) ,而雌性不具有此结构。     

江西省甘蔗有性杂交50年育种实践与体会

总结了江西省甘蔗研究所50年甘蔗有性杂交育种的成就,指出杂交后代各性状选择的不同时间,认为利用远缘杂交的F2、F3作亲本可提高后代的生活力和抗逆性,Cp、Roc和崖城系列种质是高糖育种的重要亲本源,建议今后应加强基础育种,开展生物技术育种,搞好区域合作,扩大育种规模。     

The timing of puberty in cultured female yellowtail flounder, Limanda ferruginea (Storer): Oogenesis and sex steroid production in vivo and in vitro

This study examines puberty in female yellowtail flounder, correlating macroscopic, histological and endocrine parameters at the gonadal level. Short-term ovarian tissue incubations were used to study estradiol-17β production in relation to oogenic stage. Examining 2 year classes of young flounder demonstrated that cultured females retain phenotypic plasticity in reproductive age with pubertal onset occurring in one-year, two-year and three-year-olds. Immature ovaries were steroidogenic and capable of responding to gonadotropic stimulation. Endocrine puberty in females was detected by a peak in estradiol-17β production during the cortical alveolar oocyte stage prior to any ovarian evidence of vitellogenesis. Puberty, once initiated, proceeded to ovulation within 8 to 12 months; vitellogenic oocyte development followed the group synchronous pattern. Estradiol-17β was clearly the dominant of the two measured plasma hormones during pubertal onset and throughout vitellogenesis. Plasma testosterone was consistently detectable at low levels by mid-to late-vitellogenesis. Ovaries showed the highest sensitivity to gonadotropic stimulation in vitro during late-vitellogenesis. Variable plasma levels in both estradiol-17β and testosterone occurred in preovulatory and ovulating females during the captive spawning period. Together the results show that yellowtail flounder can mature at a young age and small size when culture conditions permit. In addition, the early sensitivity to gonadotropin by the immature ovaries may be an important physiological determinant for the timing of puberty in this species.