Sex ratios in dairy cattle under various conditions

Current calving information was obtained on 35,102 single births in 2254 dairy herds. The overall proportion of males to females was 50.8%. The 5 dairy breeds did not differ. Only 6 of 111 sires studied produced calves with a sex ratio different from breed average at P≤0.5. This is the number expected by chance alone. A slight bias seems to occur when reporting the sires of the cows according to the sex of the cow's calf. The sex ratio deviated from expected in a small sample of repeat breeder cows, but when a new and larger sample of 2,084 such cows which calved was obtained, there was no change associated with service number. The time of insemination was recorded for 12,764 heifers and cows first seen in estrus in the morning and 4,799 animals first seen in estrus in the evening. There was no effect of time of insemination on sex ratio. Likewise there was no effect of age of cows or season of breeding on sex ratio at birth. Because the sex ratio for cows requiring one insemination per pregnancy was not different from repeat breeders it is suggested that the sex ratio at fertilization and birth may be similar.     

An improved colorimetric assay for aspartate and ornithine transcarbamylases

An improved colorimetric assay for ornithine and aspartate transcarbamylase has been devised. The conventional method of L. M. Prescott and M. E. Jones (1969, Anal. Biochem.32, 408–419) for the detection of ureido compounds, has been optimized and standardized to a highly reproducible, sensitive, efficient, and inexpensive method for the assay of carbamyl aspartate or citrulline, the products of aspartate transcarbamylase and ornithine transcarbamylase, respectively.     

Sheep-goat hybrid karyotypes

A “Spanish” goat female was bred to a Barbados sheep ram and gave birth to twin offspring, one of each sex. The F_l female was backcrossed to a Barbados ram and also gave birth to twins, one of each sex. The F_l female has goat-like characters and the coloration of the Barbados. Although the female Barbados is polled, the F_l female hybrid has goat-like horns. The F_l male was lost before assessments could be made. The F_l hybrid possesses a diploid chromosome number of 57 and a karyotype containing 3 unpaired metacentrics, 5 unpaired and 23 pairs of acrocentric autosomes. The male and female backcrosses have Barbados characters and coloration; however, the female has goat-like horns. The male has Barbados or sheep-like horns. The backcrosses have diploid chromosome numbers of 55 and karyotypes containing 1 unpaired and 2 pairs of metacentrics and 2 unpaired and 23 pairs of acrocentric autosomes. The sex chromosomes consist of a large acrocentric X and a small bi-armed Y in the male and 2 large acrocentric Xs in the female.     

Resonance ionization spectroscopy for multiplex sequencing of tin-labeled DNA.

A method is described for synthesis of a tin reagent, triethylstannylpropanoic acid (TESPA), and its attachment to oligonucleotide primers. Except for the expected mobility retardation, the presence of [116Sn]-TESPA did not affect the sequencing ladder on electrophoresis gels. By using [120Sn]-TESPA and [35S]-dTTP simultaneously in the Sanger procedure, DNA bands on an electrophoresis gel were first located by autoradiography and then by resonance ionization spectroscopy to demonstrate the coincidence of the signals. Previous results using stable isotopes as labels on model compounds are now confirmed by their use in actual DNA sequencing products.     

Distribution and Abundance of Mymarid Parasitoids (Hymenoptera: Mymaridae) of Sophonia rufofascia Kuoh and Kuoh (Homoptera: Cicadellidae) in Hawaii

The abundance of mymarid parasitoids attacking the two-spotted leafhopper (Sophonia rufofascia [Kuoh and Kuoh]), a polyphagous pest recently adventive to Hawaii, was monitored using yellow sticky cards deployed in several areas on the islands of Kauai and Hawaii. The yellow cards captured Chaetomymar sp. nr bagicha Narayanan, Subba Rao, & Kaur and Schizophragma bicolor (Dozier), both adventive species, and Polynema sp. Haliday, which is endemic to Hawaii (Hymenoptera: Mymaridae). The former two species were most abundant at all sites. On Kauai, there was a negative correlation between the captures of C. sp. nr bagicha and those of Polynema sp. Throughout the season, the increase in parasitoid numbers generally followed the increase in leafhopper numbers. C. sp. nr. bagicha and S. bicolor showed distinct habitat preferences. Removal of Myrica faya Aiton, an invasive weed that is a highly preferred two-spotted leafhopper host, decreased the overall numbers of captured parasitoids, but led to a twofold increase in the ratio of trapped parasitoids/hosts in weed-free areas.     

Synergistic effect of ethanol and cycloheximide on activation of freshly matured bovine oocytes

Bovine follicular oocytes were collected from ovarian antral follicles (2 to 7 mm in diameter) from slaughtered cattle. They were matured in vitro (IVM) for 23 to 24 h and then activated. In Experiment 1, 4 concentrations of ethanol were compared. The activation rates of oocytes were 4, 12, 36 and 27%, respectively, following exposure for 7 min to 0, 5, 7 and 10% ethanol. In Experiment 2, 7% ethanol was tested with exposure times of 0, 5, 7.5 and 10 min, and 6, 32, 27 and 33% of the oocytes were activated, respectively. In Experiment 3 the synergistic effect of ethanol and electric pulse was compared within 4 treatments: A) 7% ethanol alone, B) electric pulse alone, C) ethanol first and then electric pulse treatment, and D) electric pulse first followed by ethanol exposure. Of the oocytes activated, 37, 31, 28 and 51%, respectively, were from Treatments A through D. In Experiments 4 and 5 the possible synergistic effect of ethanol and a protein synthesis inhibitor, cycloheximide, was studied within 4 treatments: A) parthenogenetic control with no activation treatment, B) ethanol alone, C) cycloheximide alone, and D) ethanol treatment followed by cycloheximide. The oocyte activation rates in Experiment 4 in Treatments A through D, respectively, were 9, 44, 43 and 84%. Corresponding values for development of oocytes to the 2 to 8-cell stage after culture for 3 d (Experiment 5) were 9, 20, 14 and 45%, respectively (P<0.05). In conclusion, exposure to 7% ethanol for 5 min followed by incubation with cycloheximide was the best activation treatment for bovine IVM oocytes.     

Dimensions of global population projections: what do we know about future population trends and structures?

The total size of the world population is likely to increase from its current 7 billion to 8–10 billion by 2050. This uncertainty is because of unknown future fertility and mortality trends in different parts of the world. But the young age structure of the population and the fact that in much of Africa and Western Asia, fertility is still very high makes an increase by at least one more billion almost certain. Virtually, all the increase will happen in the developing world. For the second half of the century, population stabilization and the onset of a decline are likely. In addition to the future size of the population, its distribution by age, sex, level of educational attainment and place of residence are of specific importance for studying future food security. The paper provides a detailed discussion of different relevant dimensions in population projections and an evaluation of the methods and assumptions used in current global population projections and in particular those produced by the United Nations and by IIASA.     

The clathrin adaptor complex 1 directly binds to a sorting signal in Ste13p to reduce the rate of its trafficking to the late endosome of yeast

Yeast trans-Golgi network (TGN) membrane proteins maintain steady-state localization by constantly cycling to and from endosomes. In this study, we examined the trafficking itinerary and molecular requirements for delivery of a model TGN protein A(F-->A)-alkaline phosphatase (ALP) to the prevacuolar/endosomal compartment (PVC). A(F-->A)-ALP was found to reach the PVC via early endosomes (EEs) with a half-time of approximately 60 min. Delivery of A(F-->A)-ALP to the PVC was not dependent on either the GGA or adaptor protein 1 (AP-1) type of clathrin adaptors, which are thought to function in TGN to PVC and TGN to EE transport, respectively. Surprisingly, in cells lacking the function of both GGA and AP-1 adaptors, A(F-->A)-ALP transport to the PVC was dramatically accelerated. A 12-residue cytosolic domain motif of A(F-->A)-ALP was found to mediate direct binding to AP-1 and was sufficient to slow TGN-->EE-->PVC trafficking. These results suggest a model in which this novel sorting signal targets A(F-->A)-ALP into clathrin/AP-1 vesicles at the EE for retrieval back to the TGN.