Consortships and conceptions in captive rhesus macaques (Macaca mulatta)

A captive group of rhesus macaques (Macaca mulatta) was observed during the breeding season to determine if consortship behavior, rather than promiscuous matings, resulted in higher reproductive success for either partner. The 38 adult females in this group were observed “in consort” with the 5 adult or 4 subadult males on 179 occasions. Most of these consortships were short-term, lasting less than one day. Six females engaged in consortships with one male that spanned more than three days, but the majority of these long-term associations did not result in a pregnancy with that male. The term “consortship” has been traditionally accepted as a specific nonhuman primate mating pattern, but the exact nature of this behavioral pattern and its evolutionary importance have been less clearly understood. Consort behavior could be considered a precursor to a monogamous mating system if long-term exclusive sexual associations resulted in higher reproductive success for the participants. But this study demonstrates that for rhesus macaques, who exhibit both consort behavior and more promiscuous matings, there is no clear reproductive advantage to long-term consortships. In light of the inconsistent use of the term consortship, the possible adaptive significance of an exclusive male-female sexual association for the evolution of human mating patterns needs to be reevaluated.     

Synergy between Apc min and an activated ras mutation is sufficient to induce colon carcinomas.

Colon carcinomas appear to arise from the cumulative effect of mutations to several genes (APC, DCC, p53, ras, hMLH1, and hMSH2). By using novel colonic epithelial cell lines derived from the Immorto mouse, named the YAMC (young adult mouse colon) cell line, and an Immorto-Min mouse hybrid, named the IMCE (Immorto-Min colonic epithelial) cell line, carrying the Apc min mutation, we investigated the effect of an activated v-Ha-ras gene on tumor progression. The YAMC and IMCE cell lines are normal colonic epithelial cell lines which are conditionally immortalized by virtue of expression of a temperature-sensitive simian virus 40 (SV40) large T antigen. Under conditions which permit expression of a functional SV40 large T antigen (33 degrees C plus gamma interferon), neither the YAMC nor the IMCE cell line grows in soft agar or is tumorigenic in nude mice. In vitro, when the SV40 large T antigen is inactivated (39 degrees C without gamma interferon), the cells stop proliferating and die. By infecting the YAMC and IMCE cell lines with a replication-defective psi2-v-Ha-ras virus, we derived cell lines which overexpress the v-Ha-ras gene (YAMC-Ras and IMCE-Ras). In contrast to the parental cell lines, under conditions in which the SV40 large T antigen is inactive, both the YAMC-Ras and IMCE-Ras cell lines continue to proliferate. Initally YAMC-Ras cells do not form tumors; however, tumors are visible after 90 days of incubation. IMCE-Ras cells form colonies in soft agar under both permissive and nonpermissive culture conditions. Furthermore, IMCE-Ras cells form tumors in nude mice within 3 weeks. The phenotype of the IMCE-Ras cell line thus clearly demonstrates that a defective Apc allele and an activated ras gene are sufficient to transform normal colonic epithelial cells and render them tumorigenic.     

Embryonic survival in the uterus of ewes inseminated at the uterotubal junction on Day 32 post partum

Experiments were conducted to determine 1) if pregnancy initiated on Day 32 post partum would be maintained until lambing, 2) if there is a difference in the ability of the previously gravid or nongravid uterine horn to maintain pregnancy, and 3) if season has an effect on embryo loss. Estrus was induced in ewes on Day 32 post partum. At estrus, ewes were inseminated surgically at the uterotubal junction and assigned to the following groups: 1) inseminated at estrus and laparotomized on Day 3 to collect embryos for determination of fertilization rate (C), 2) inseminated in the previously gravid uterine horn (PG), 3) inseminated in the previously nongravid uterine horn (NG), and 4) inseminated when both horns were previously gravid (BG). Ewes pregnant in the PG, NG and BG groups were allowed to lamb. Conception rate in Group C at embryo collection was 70%. Embryo loss, based on concentrations of progesterone at Day 18 post insemination, was 43, 19 and 18% in the BG, NG and PG group, respectively. The high embryo loss in Group BG occurred only during the breeding season. Only 24% of the ewes that had been inseminated lambed. This was due to the prepartum loss of embryos and fetuses (47, 48 and 33% in Group BG, NG and PG, respectively. In conclusion, the detrimental effects of the uterus on embryo survival was evident within 18 d post insemination in Group BG (breeding season), and embryo loss prior to lambing was high in all the treatment groups (both seasons).     

Isolation and characterization of new polymorphic simple sequence repeat loci in grape (Vitis vinifera L.).

Four new simple sequence repeat (SSR) loci (designated VVMD5, VVMD6, VVMD7, and VVMD8) were characterized in grape and analyzed by silver staining in 77 cultivars of Vitis vinifera. Amplification products ranged in size from 141 to 263 base pairs (bp). The number of alleles observed per locus ranged from 5 to 11 and the number of diploid genotypes per locus ranged from 13 to 27. At each locus at least 75% of the cultivars were heterozygous. Alleles differing in length by only 1 bp could be distinguished by silver staining, and size estimates were within 1 or 2 bp, depending on the locus, of those obtained by fluorescence detection at previously reported loci. Allele frequencies were generally similar in wine grapes and table grapes, with some exceptions. Some alleles were found only in one of the two groups of cultivars. All 77 cultivars were distinguished by the four loci with the exception of four wine grapes considered to be somatic variants of the same cultivar, 'Pinot noir', 'Pinot gris', 'Pinot blanc', and 'Meunier'; two table grapes that are known to be synonymous, 'Keshmesh' and 'Thompson Seedless'; and three table grapes, 'Dattier', 'Rhazaki Arhanon', and 'Markandi', the first two of which have been suggested to be synonymous. Although the high polymorphism at grape SSR loci suggests that very few loci would theoretically be needed to separate all cultivars, the economic and legal significance of grape variety identification requires the increased resolution that can be provided by a larger number of loci. The ease with which SSR markers and data can be shared internationally should encourage their broad use, which will in turn increase the power of these markers for both identification and genetic analysis of grape. Key words : grape, Vitis, microsatellite, simple sequence repeat, DNA typing, identification.     

Maintenance of Weight Loss: A Needs Assessment

This study identified facilitators and obstacles to maintenance of weight loss following a very-low-calorie-diet and behavior modification program. A survey was mailed to a random sample of 178 program completers and received a 61% response rate; the most frequent follow-up period was more than 2 years. Twenty-nine percent reported weighing the same (within 10 lbs) or less than the end of their participation in the treatment program (maintainers), while 71% reported their present weight was a mean of 65% higher than their initial weight loss (regainers). Maintainers were significantly more likely to report engaging in regular aerobic exercise, attending a maintenance support group, and confidence in their ability to manage their weight in the future, while regainers were more likely to report stress and motivation as frequent weight management obstacles. Respondents consistently identified the need for low/no cost ongoing support. Maintainers and relapsers reported similar challenges in managing their weight, yet with different results, suggesting the need to identify subgroups for which different post-treatment support options could be applied.     

Simple electromyographic biofeedback treatment for chronic pediatric constipation/encopresis: Preliminary report

Pediatric constipation/encopresis is thought to be due, in part, to paradoxical constriction of the external anal sphincter (EAS) muscle during attempted defecation. This inappropriate contraction can lead to delayed, impacted, painful, and infrequent bowel movements. Standard Medical Care (SMC) involves disimpaction with enemas, followed by laxative therapy and diet modification, to maintain frequent soft stools. Using the case control method, the efficacy of SMC alone was compared with SMC plus EAS electromyographic biofeedback aimed at eliminating paradoxical contraction. Thirteen consecutive chronically constipated children received SMC plus biofeedback, and were compared with 13 age- and sex-matched children who received only SMC. Biofeedback subjects demonstrated post-treatment elimination of EAS paradoxical constriction. At 16 months follow-up parents of biofeedback children reported significantly greater improvement in constipation, encopresis, laxative use, and painful bowel movements compared to SMC.This research report was supported by the NIH under grant No. RO1 HD 28160.     

RIBOSOMAL-DNA,MITOCHONDRIAL-DNA,CHROMOSOMAL, AND ALLOZYMIC STUDIES ON A CONTACT ZONE IN THE POCKET GOPHER,GEOMYS

We studied 75 individuals of the Plains pocket gopher, Geomys bursarius, from eastern New Mexico, where the subspecies major and knoxjonesi hybridize. Each individual was examined for chromosome number, ribosomal DNA, mitochondrial DNA, and three protein systems for which reference parental populations were fixed for alternative alleles. Twenty individuals were indistinguishable from parental major, 14 individuals were indistinguishable from parental knoxjonesi, and 41 individuals had genotypes composed of combinations of character states that distinguish the two parental types. The parental types appear to represent discrete genetic entities that have restricted introgression across a narrow hybrid zone (width approximately 3 km, using the 20/80 criterion). Parental types overlap in geographic distribution near the center of the zone, and changes in mitochondrial DNA and the five nuclear markers are concordant across the zone. It is probable that there is premating isolation between knoxjonesi males and major females. The frequencies of individuals with certain genotypic combinations within our sample imply differential reproductive success of certain genotypes. We propose that F₁'s and highly heterozygous males are sterile and that hybrid females are less fertile than parental females. These postmating factors, along with premating isolation for one of the reciprocal crosses, probably account for the restriction of gene flow across the contact zone. The structure of the zone can be explained by the “dynamic equilibrium” model.     

Expression cloning of oncogenes by retroviral transfer of cDNA libraries.

a cDNA library transfer system based on retroviral vectors has been developed for expression cloning in mammalian cells. The use of retroviral vectors results in stable cDNA transfer efficiencies which are at least 100-fold higher than those achieved by transfection and therefore enables the transfer and functional screening of very large libraries. In our initial application of retroviral transfer of cDNA libraries, we have selected for cDNAs which induce oncogenic transformation of NIH 3T3 fibroblasts, as measured by loss of contact inhibition of proliferation. Nineteen different transforming cDNAs were isolated from a total of 300,000 transferred cDNA clones. Three of these cDNAs were derived from known oncogenes (raf-1, lck, and ect2), while nine others were derived from genes which had been cloned previously but were not known to have the ability to transform fibroblasts (beta-catenin, thrombin receptor, phospholipase C-gamma 2 and Spi-2 protease inhibitor genes). The Spi-2 cDNA was expressed in antisense orientation and therefore is likely to act as an inhibitor of an endogenous transformation suppressor. Seven novel cDNAs with transforming activities, including those for three new members of the CDC24 family of guanine nucleotide exchange factors, were also cloned from the retroviral cDNA libraries. Retroviral transfer of libraries should be generally useful for cloning cDNAs which confer selectable phenotypes on many different types of mammalian cells.