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.     

Prebiotic synthesis of diaminopyrimidine and thiocytosine

The reaction of guanidine hydrochloride with cyanoacetaldehyde gives high yields (40–85%) of 2,4-diaminopyrimidine under the concentrated conditions of a drying lagoon model of prebiotic synthesis, in contrast to the low yields previously obtained under more dilute conditions. The prebiotic source of cyanoacetaldehyde, cyanoacetylene, is produced from electric discharges under reducing conditions. The effect of pH and concentration of guanidine hydrochloride on the rate of synthesis and yield of diaminopyrimidine were investigated, as well as the hydrolysis of diaminopyrimidine to cytosine, isocytosine, and uracil. Thiourea also reacts with cyanoacetaldehyde to give 2-thiocytosine, but the pyrimidine yields are much lower than with guanidine hydrochloride or urea. Thiocytosine hydrolyzes to thiouracil and cytosine and then to uracil. This synthesis would have been a significant prebiotic source of 2-thiopyrimidines and 5-substituted derivatives of thiouracil, many of which occur in tRNA. The applicability of these results to the drying lagoon model of prebiotic synthesis was tested by dry-down experiments where dilute solutions of cyanoacetaldehyde, guanidine hydrochloride, and 0.5m NaCl were evaporated over varying periods of time. The yields of diaminopyrimidine varied from 1 to 7%. These results show that drying lagoons and beaches may have been major sites of prebiotic syntheses.     

Desensitization of the Neurokinin 1 Receptor Is Mediated by the Receptor Carboxy-Terminal Region, but Is Not Caused by Receptor Internalization

Abstract: The carboxy-terminal cytoplasmic regions of the rat neurokinin 1 (substance P) and neurokinin 2 (neurokinin A) receptors have been exchanged to determine if this region of the neurokinin 1 receptor is involved in its desensitization. When expressed at similar levels in stably transfected Chinese hamster ovary (CHO) cell lines, receptors containing the carboxy-terminal region of the neurokinin 1 receptor desensitized significantly more (as measured by reduction of the inositol 1,4,5-trisphosphate response) when preexposed for 1 min to 1 µ M neurokinin, indicating a role for the carboxy-terminal region of the neurokinin 1 receptor in its desensitization. Measurement of receptor internalization using radiolabeled neurokinins (0.3 n M ) indicated that ∼75–80% of the receptors were internalized in each cell line after 10 min at 37°C, with no observable correlation between neurokinin receptor desensitization and internalization. Measurement of loss of receptor surface sites for cell lines CHO NK1 and CHO NK1NK2 following exposure to 1 µ M substance P also indicated no obvious relationship between the percent desensitization and percent of receptors internalized. Also, two inhibitors of neurokinin 1 receptor internalization, phenylarsine oxide and hyperosmolar sucrose, did not inhibit neurokinin 1 receptor desensitization. The protein kinase inhibitors Ro 31-8220, staurosporine, and Zn²⁺ had no effect on neurokinin 1 receptor desensitization, indicating that the kinases affected by these agents are not rate-limiting in neurokinin 1 receptor desensitization in this system.     

Inbreeding and incompatibility in Trichogramma nr. brassicae: evidence and implications for quality control

Inbreeding effects and incompatibility relationships were examined in strains of the egg parasitoid Trichogramma nr brassicae (Hymenoptera: Trichogrammatidae) from southeastern Australia. Crosses between strains provided weak evidence of incompatibility in a few cases. However sex ratio in crosses within strains tended to be more female-biased than in crosses between strains. Inbreeding was imposed for four generations (F>0.59) of sib mating. The fitness of inbred strains was compared to that of outbred strains generated by crossing the inbred strains. No effects of inbreeding were found for any of the four female traits examined (fecundity, body length, head width and hind tibia length), indicating that T. nr. brassicae is not subjected to inbreeding depression. Inbreeding effects were also not found for male mating success as expected for the haploid sex. There were differences among strains for all traits apart from fecundity, indicating heritable variation. Strain differences for fitness measures were uncorrelated with wasp size. The potential use of inbreeding in the quality control of Trichogramma for mass-release is discussed. Inbreeding may be a useful tool in minimising the effects of laboratory adaptation, thereby extending the useful life of a strain.     

LIFE-HISTORY ADAPTATION AND REPRODUCTIVE ISOLATION IN A GRASSHOPPER HYBRID ZONE

Patterns of life-history adaptation and reproductive isolation were investigated in the acridid grasshoppers Melanoplus sanguinipes and M. devastator, which hybridize along an altitudinal gradient in the Sierra Nevada of California. Melanoplus sanguinipes females crossed with M. devastator males produced eggs that were approximately half as viable as eggs from other crosses. Diminished viability was not attributable either to infection by Wolbachia pipientis or to failure of sperm transfer. When offered an opportunity to choose a mate, females from all populations discriminated against males of the other species, whereas in no-choice tests measuring copulation duration only females from the tails of the clines showed preferences. Melanoplus sanguinipes, found at high elevations where the growing season is short, exhibited faster egg hatch, faster larval development, smaller adult body sizes, and smaller clutch sizes than M. devastator. Melanoplus devastator, from California's Central Valley, endured a hot and dry summer in a reproductive diapause that was absent in M. sanguinipes. Clines in reproductive diapause and clutch size coincided with the region of reproductive incompatibility. Development time, body size, and hatch time also changed across the hybrid zone, but the regions of largest transitions in these traits were either difficult to locate using the limited populations studied here or were not coincident with the zone's center. A method is described for combining ecological and phylogenetic analyses to address the unknown issue of whether life-history divergence has conributed to reproductive isolation in this system.     

Computed three-dimensional structures for theras-binding domain of theraf-p74 protein complexed withras-p21 and with its suppressor protein, rap-1A

The three-dimensional structures of theras-p21 protein and its protein inhibitor, rap-1A, have been computed bound to theras-binding domain, RBD (residues 55–131), of theraf-p74 protein, a critical target protein ofras-p21 in theras-induced mitogenic signal transduction pathway. The coordinates of RBD have been reconstructed from the stereoview of an X-ray crystal structure of this domain bound to rap-1A and have been subjected to energy minimization. The energy-minimized structures of bothras- p21 and rap-1A, obtained in previous studies, have been docked against RBD, using the stereo figure of the RBD-rap-1A complex, based on a six-step procedure. The final energy-minimized structure of rap-1A-RBD is identical to the X-ray crystal structure. Comparison of theras-p21- and rap-1A-RBD complexes reveals differences in the structures of effector domains ofras-p21 and rap-1a, including residues 32–47, a domain that directly interacts with RBD, 60–66, 96–110, involved in the interaction ofras-p21 withjun kinase (JNK) andjun protein, and 115–126, involved in the interaction of p21 with JNK. The structure of the RBD remained the same in both complexes with the exception of small deviations in its-2 binding loop (residues 63–71) and residues 89–91, also involved in binding to rap-1A. The results suggest that the binding of these two proteins to RBD may allow them to interact with other cellular target proteins such as JNK andjun.     

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).     

Water relations and leaf chemistry of Chrysothamnus nauseosus ssp. consimilis (Asteraceae) and Sarcobatus vermiculatus (Chenopodiaceae)

At Mono Lake, California, we investigated field water relations, leaf and xylem chemistry, and gas exchange for two shrub species that commonly co-occur on marginally saline soils, and have similar life histories and rooting patterns. Both species had highest root length densities close to the surface and have large tap roots that probably reach ground water at 3.4-5.0 m on the study site. The species differed greatly in leaf water relations and leaf chemistry. Sarcobatus vermiculatus had a seasonal minimum predawn xylem pressure potential (ψ_pd) of -2.7 MPa and a midday potential (ψ_md) of -4.1 MPa. These were significantly lower than for Chrysothamnus nauseosus, which had a minimum ψ_pd of -1.0 MPa and ψ_md of -2.2 MPa. Sarcobatus had leaf Na of up to 9.1 % and K up to 2.7 % of dry mass, and these were significantly higher than for Chrysothamnus which had seasonal maxima of 0.4% leaf Na and 2.4 % leaf K. The molar ratios of leaf K/Na, Ca/Na, and Mg/Na were substantially lower for Sarcobatus than for Chrysothamnus. Xylem ionic contents indicated that both species excluded some Na at the root, but that Chrysothamnus was excluding much more than Sarcobatus. The higher Na content of Sarcobatus leaves was associated with greater leaf succulence, lower calculated osmotic potential, and lower xylem pressure potentials. Despite large differences in water relations and leaf chemistry, these species maintained similar diurnal patterns and rates of photosynthesis and stomatal conductance to water vapor diffusion. Sarcobatus ψ_pd may not reflect soil moisture availability due to root osmotic and hydraulic properties.     

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.