Fertility of stallion semen processed, frozen and thawed by a new procedure

The fertility of frozen-thawed and fresh semen from three stallions was compared in a trial using a randomized block design and 90 mares for 108 cycles. Semen was collected every third day, diluted to 50 x 10(6) sperm/ml with a citrate-based centrifugation medium, and centrifuged. The cells were resuspended at 700 x 10(6) progressively motile sperm/1.0 ml of added lactose-EDTA-egg yolk extender containing 4% glycerol, packaged by placing 0.55 ml into polypropylene straws, and frozen. Semen was thawed by immersion in 75 degrees C water for 10 sec. All of the 43 ejaculates collected were frozen, but 21 were discarded because progressive sperm motility was <35% immediately after thawing or <40% after 30 min of incubation at 37 degrees C. semen from the same stallions was collected daily for inseminations with fresh semen. Semen containing 200 x 10(6) progressively motile sperm was added to 10 ml of heated skimmilk extender. Mares were inseminated daily starting on the third day of estrus or when a >/=4-cm follicle was detected, whichever came later, and continuing through the end of estrus or for nine days. Based on palpation per rectum on day 50 postovulation, the pregnancy rates from inseminations during one estrus were 50, 56 and 61% with frozen semen and 67, 67 and 61% with fresh semen (P>0.05) from the three stallions, respectively. Thus, mean pregnancy rate with frozen semen was 86% of the rate attained with fresh semen.     

Infanticide and fertility among Eskimos: A computer simulation

Until recently, certain Eskimo groups were reported to practice female infanticide in the belief that the time spent suckling a girl would delay the mother's next opportunity to bear a son, males being preferred to females because of their future role as providers in a hunting economy. From sex ratios in census data, rates of female infanticide of up to 66% for some groups have been inferred, leading some ethnographers to conclude that these groups were headed for extinction. Eskimo beliefs regarding the effects of infanticide on fertility, however, are in accord with the results of research on the relation of fertility and lactation: The cessation of lactation following infanticide would significantly shortern the expected interval until the next birth. Given this fact and available field data regarding the parameters of Eskimo population growth, the present computer simulation indicates that Eskimo populations could sustain a rate of 30% female infanticide and still survive. Higher reported rates are explained as the combined result of female infanticide plus the tendency of ethnographers to overestimate to overestimate the ages of juvenile females relative to juvenile males.     

Are there costs in the repeated mating activities of female Southern stink bugs Nezara viridula?

Mating is an energy demanding process, imposing risks to physical injuries, pathogen infection and predation. Nevertheless, repeated and multiple mating are widespread even in insect species where nuptial gifts are not involved. The effects of repeated mating, by the same male, are examined on the reproductive performance of female Southern green stink bug Nezara viridula (L.). Fecundity is reduced in females mated three or four times, although there is increased longevity. Females mated once or twice produce more egg clusters and concentrate egg‐laying activity in the early part of adult life, whereas those mating more often lay eggs throughout the life span, with fewer egg clusters. Although fecundity is negatively affected by the number of matings, egg fertility remains unaffected.     

Sociobiology's relevance to modern society: commentary on two articles published here

This article looks at two articles recently published here, one by R. Hopcroft [“Sex, status, and reproductive success in the contemporary United States,” Evolution and Human Behavior 27 (2006) 104–120] the second by M. Fieder and S. Huber [“The effects of sex and childlessness on reproductive effort in modern humans,” Evolution and Human Behavior 28 (2007) 392–398]. They both report a positive relationship between male income and male fertility, which marks a real advancement in our knowledge. Hopcroft speculates at the end of her article that the father's status and female fertility will be positive, too. At this point, this will depend on her and others' reaction to the efforts of S. Huber, F. Bookstein, and M. Fiedler. (2010). Socioeconomic status, education, and reproduction in modern women: an evolutionary perspective. American Journal of Human Biology, 22, 578-587. M. Fieder and S. Huber. (2007). The effects of sex and childlessness on the association between status and reproductive output in modern society. Evolution and Human Behavior, 2, 392-398. are not explicit about this relationship; their closing lines just leave open the possibility that it might be positive. The conclusion is that sociobiology is not really relevant yet to the understanding of modern, industrial society, urban civilization in general, except to show us the various restraints imposed by inborn human nature.     

Ram seminal plasma improves pregnancy rates in ewes cervically inseminated with ram semen stored at 5 °C for 24 hours

In this study, we compared pregnancy rates obtained using ram semen stored at 5 °C for 24 h, with ram or bull seminal plasma (SP) added to TRIS-egg yolk extender. During the breeding period, 670 adult Corriedale ewes were cervically inseminated with semen (2 × 10⁸ sperm in a volume of 0.2 mL) from eight adult Corriedale rams. Ejaculates, obtained using an artificial vagina, were split into three aliquots and diluted with the following: TRIS-egg yolk based extender (T), T + 30% ram SP (R), or T + 30% bull SP (B). Samples were refrigerated and stored at 5 °C for 24 h until used for AI. Pregnancy was assessed by ultrasonography 35 to 40 d after AI. Pregnancy rate was not affected by ram (P = 0.77) or breeding period (P = 0.43), and there were no interactions between extender and ram (P = 0.94), or extender and breeding period (P = 0.24). However, there was an effect of extender (P = 0.0009) on pregnancy rates; ram SP, but not bull SP, increased pregnancy rates compared with extender without SP (49.7, 38.1, and 31.1%, for R, B, and T respectively). In conclusion, ram SP added to TRIS-egg yolk extender had a beneficial effect on the pregnancy rate of ram sperm stored at 5 °C for 24 h and used for cervical insemination of ewes.     

Large P body-like RNPs form in C. elegans oocytes in response to arrested ovulation, heat shock, osmotic stress, and anoxia and are regulated by the major sperm protein pathway

As Caenorhabditis elegans hermaphrodites age, sperm become depleted, ovulation arrests, and oocytes accumulate in the gonad arm. Large ribonucleoprotein (RNP) foci form in these arrested oocytes that contain RNA-binding proteins and translationally masked maternal mRNAs. Within 65 min of mating, the RNP foci dissociate and fertilization proceeds. The majority of arrested oocytes with foci result in viable embryos upon fertilization, suggesting that foci are not deleterious to oocyte function. We have determined that foci formation is not strictly a function of aging, and the somatic, ceh-18, branch of the major sperm protein pathway regulates the formation and dissociation of oocyte foci. Our hypothesis for the function of oocyte RNP foci is similar to the RNA-related functions of processing bodies (P bodies) and stress granules; here, we show three orthologs of P body proteins, DCP-2, CAR-1 and CGH-1, and two markers of stress granules, poly (A) binding protein (PABP) and TIA-1, appear to be present in the oocyte RNP foci. Our results are the first in vivo demonstration linking components of P bodies and stress granules in the germ line of a metazoan. Furthermore, our data demonstrate that formation of oocyte RNP foci is inducible in non-arrested oocytes by heat shock, osmotic stress, or anoxia, similar to the induction of stress granules in mammalian cells and P bodies in yeast. These data suggest commonalities between oocytes undergoing delayed fertilization and cells that are stressed environmentally, as to how they modulate mRNAs and regulate translation.     

A Moricandia arvensis– based cytoplasmic male sterility and fertility restoration system in Brassica juncea

 A cytoplasmic male-sterility system has been developed in mustard (Brassica juncea) following repeated backcrossings of the somatic hybrid Moricandia arvensis (2n=28, MM)+B. juncea (2n=36, AABB), carrying mitochondria and chloroplasts from M. arvensis, to Brassica juncea. Cytoplasmic male-sterile (CMS) plants are similar to normal B. juncea; however, the leaves exhibit severe chlorosis resulting in delayed flowering. Flowers are normal with slender, non-dehiscent anthers and excellent nectaries. CMS plants show regular meiosis with pollen degeneration occurring during microsporogenesis. Female fertility was normal. Genetic information for fertility restoration was introgressed following the development of a M. arvensis monosomic addition line on CMS B. juncea. The additional chromosome paired allosyndetically with one of the B. juncea bivalents and allowed introgression. The putative restorer plant also exhibited severe chlorosis similar to CMS plants but possessed 89% and 73% pollen and seed fertility, respectively, which subsequently increased to 96% and 87% in the selfed progeny. The progeny of the cross of CMS line with the restorer line MJR-15, segregated into 1 fertile : 1 sterile. The CMS (Moricandia) B. juncea, the restorer (MJR-15), and fertility restored F₁ plants possess similar cytoplasmic organellar genomes as revealed by ‘Southern’ analysis. Received: 17 September 1997 / Accepted: 18 February 1998     

转基因植物生产动物疫苗的研究及应用

转基因植物生产动物疫苗的研究及应用范国昌１,２山松１钱凯先２沈桂芳１（１．中国农业科学院生物技术研究中心,北京１０００８１）（２．浙江大学生物科学与技术系,杭州３１００２７）ＲｅｓｅａｒｃｈａｎｄＡｐｐｌｉｃａｔｉｏｎｏｎＴｒａｎｓｇｅｎｉｃＰｌａｎ...     

Genetic structure and domestication footprints of the tusk,coat color,and ear morphology in East Chinese pigs

The domestication and artificial selection of wild boars have led to dramatic morphological and behavioral changes, especially in East Chinese (ECN) pigs. Here, we provide insights into the population structure and current genetic diversity of representative ECN pig breeds. We identify a 500-kb region containing six tooth development-relevant genes with almost completely different haplotypes between ECN pigs and Chinese wild boars or European domestic pigs. Notably, the c.195A>G missense mutation in exon 2 of AMBN may cause alterations in its protein structure associated with tusk degradation in ECN pigs. In addition, ESR1 may play an important role in the reproductive performance of ECN pigs. A major haplotype of the large lop ear-related MSRB3 gene and eight alleles in the deafness-related GRM7 gene may affect ear morphology and hearing in ECN pigs. Interestingly, we find that the two-end black (TEB) coat color in Jinhua pigs is most likely caused by EDNRB with genetic mechanisms different from other Chinese TEB pigs. This study identifies key loci that may be artificially selected in Chinese native pigs related to the tusk, coat color, and ear morphology, thus providing new insights into the genetic mechanisms of domesticated pigs.