Enrichment of Y‐Chromosome‐Bearing Bull Spermatozoa by Swim‐up Through a Column

With the advancement of assisted reproductive biotechnologies, preselecting the sex of offspring has become an important goal for cattle and other livestock breeding as well as for research. The aim of this study was to investigate the feasibility of producing enriched pools of X‐ or Y‐chromosome‐bearing sperm by vertical swim‐up through a long, narrow column. Sperm recovered from the top portion of the column was predominantly Y‐bearing (60%, p < 0.05), which were capable of fertilizing matured oocytes and produce significantly more male embryos compared with standard swim‐up protocol.     

安徽特色农业可持续发展研究

当前安徽特色农业呈不断发展趋势：专业化和产业化不断增强、基础设施逐步改善、科技扶持力度不断增强、农业旅游等功能有所拓展。但是也存在优良品种保护和开发力度不够,生产技术水平相对较低,基层农技推广和农村实用人才难以满足需求,基础设施建设投入不足,主产区生态环境保护不够,产业化有待推进,休闲、观光旅游功能拓展缓慢等问题。建议从五个方面推进安徽特色农业可持续发展：加强基层农业科技人才开发;推进特色农业产业化发展;加强优良品种开发与保护;完善农业基础设施建设;保护生态环境,发展农业旅游。     

Surveyor v: lunar surface mechanical properties

The mechanical properties of the lunar soil at the Surveyor V landing site seem to be generally consistent with values determined for soils at the landing sites of Surveyor I and III. These three maria sites are hundreds of kilometers apart. However, the static bearing capability may be somewhat lower than that at the previous landing sites (2 x 10(5) to 6 x 10(5) dynes per square centimeter or 3 to 8 pounds per square inch). The results of the erosion experiment, the spacecraft landing effects, and other observations indicate that the soil has significant amounts of fine-grained material and a measurable cohesion.     

Suppression by actidione of development of rat liver L-tyrosine : 2-oxoglutarate aminotransferase activity

The development of L-tyrosine : 2-oxoglutarate aminotransferase in newborn rats is suppressed by actidione (cycloheximide), an inhibitor of protein biosynthesis, administered immediately after birth.     

Aneuploidy drives genomic instability in yeast

Aneuploidy decreases cellular fitness, yet it is also associated with cancer, a disease of enhanced proliferative capacity. To investigate one mechanism by which aneuploidy could contribute to tumorigenesis, we examined the effects of aneuploidy on genomic stability. We analyzed 13 budding yeast strains that carry extra copies of single chromosomes and found that all aneuploid strains exhibited one or more forms of genomic instability. Most strains displayed increased chromosome loss and mitotic recombination, as well as defective DNA damage repair. Aneuploid fission yeast strains also exhibited defects in mitotic recombination. Aneuploidy-induced genomic instability could facilitate the development of genetic alterations that drive malignant growth in cancer.     

Natural Selection for Miillerian Mimicry in Heliconius erato in Costa Rica

The natural color pattern of individuals of the unpalatable and mimetic butterfly Heliconius erato was altered to a unique nonmimetic pattern. When returned to natural populations, the nonmimetic individuals remained for shorter periods of time and received more wing damage indicative of predator attacks than did the controls. The results indicate that Müllerian mimicry was functioning to protect the butterflies from predation.