Colony Member Discrimination by Juvenile Columbian Ground Squirrels (Spermophilus columbianus)

Whether an individual strives to breed or restrains from reproducing directly but increases the fitness of another individual through its help, may be viewed as a result of a trade-off between fitness costs and benefits arising from this decision. A population of the large carpenter bee Xylocopa sulcatipes Maa was studied in southeast Israel over a two year period. Female reproductive success, in terms of genetic representation in the gene pool (genetic gain), was calculated using coefficients of relatedness and the number of offspring produced by solitary, reproductively dominant and helper bees of social nests. In one year helper females, that shared a nest with a related female accrued a higher genetic gain than did solitary females. In the subsequent year solitary females did better than the helper bees. In nests founded by unrelated females a helper bee accrued only little genetic gain. However, evidence is presented to show that subordinate behaviour can have an adaptive value and can ultimately be beneficial through nest inheritance by the subordinate bee.     

CHLOROPLAST DNA VARIATION AND THE PHYLOGENY OF HORDEUM (POACEAE)

Restriction site variation in the chloroplast genome (cpDNA) was surveyed among 37 taxa or cytotypes (40 accessions) of the genus Hordeum. Seventeen restriction enzymes were employed, and a total of 491 restriction sites were assayed. Of these, 120 were variable among the taxa, including 70 synapomorphies. The level of sequence divergence (p) among species of Hordeum varied from 0.0 to 0.017, indicating that Hordeum possesses an about-average level of cpDNA diversity as compared to most other genera of flowering plants for which data are available. Wagner and polymorphism parsimony phytogenies were constructed from the restriction site data. These analyses divided the genus into several distinct groups; 1) American taxa; 2) diploid H. marinum; 3) Asian taxa; 4) H. vulgare-H. bulbosum; and 5) the H. murinum complex. Bootstrap-based confidence limits provided statistical support for the monophylesis of the latter three groups. The cpDNA data showed remarkably good congruence with previously published isoenzymatic, molecular, cytological, and crossing data.     

Intergeneric hybridization between Hordeum and Hordelymus (Poaceae)

Intergeneric hybridization between the monotypic Eurasian genus Hordelymus and species of Hordeum was performed. Hybrids were obtained in nine combinations and the meiotic pairing was analyzed in four combinations (6 families). Hordelymus europaeus is probably an alloploid with two different genomes. The very low pairing in the hybrids with H. jubatum, H. brachyantherum , and H. pusillum indicates that these species do not have any genomes in common with Hordelymus. The hybrids with H. depressum have an intermediate pairing which suggests that there is a certain homoeology in one genome.     

Detection of renal cell carcinoma-associated markers via proteome- and other 'ome'-based analyses.

Proteome analysis has rapidly developed in the post-genome era and is now widely accepted as the complementary technology for genetic profiling. It has been shown to be a powerful tool for studying human diseases and for identifying novel prognostic, diagnostic and therapeutic markers. This review focuses on the identification of new biomarkers and therapeutic targets for renal cell carcinoma using different 'ome'-based technologies.     

Ligand-specific dose-response of heterologously expressed olfactory receptors.

Primary olfactory neuronal cultures exposed to odorant stimulation have previously exhibited concentration-related effects in terms of intracellular cAMP levels and adenylate cyclase activity [Ronnett, G.V., Parfitt, D.J., Hester, L.D. & Snyder, S.H. (1991) PNAS88, 2366-2369]. Maximal stimulation occurred for intermediate concentrations, whereas AC activity declined for both low and high odorant concentrations. We suspected that this behavior might be ascribed to the intrinsic response of the first molecular species concerned by odorant detection, i.e. the olfactory receptor itself. In order to check this hypothesis, we developed an heterologous expression system in mammalian cells to characterize the functional response of receptors to odorants. Two mammalian olfactory receptors were used to initiate the study, the rat I7 olfactory receptor and the human OR17-40 olfactory receptor. The cellular response of transfected cells to an odorant stimulation was tested by a spectrofluorimetric intracellular calcium assay, and proved in all cases to be dose-dependent for the known ligands of these receptors, with an optimal response for intermediate concentrations. Further experiments were carried out with the rat I7 olfactory receptor, for which the sensitivity to an odorant, indicated by the concentration yielding the optimal calcium response, depended on the carbon chain length of the aldehydic odorant. The response is thus both ligand-specific and dose-dependent. We thus demonstrate that a differential dose-response originates from the olfactory receptor itself, which is thus capable of efficient discrimination between closely related agonists.     

Lactate and epinephrine during exercise in altitude natives

Kayser, Bengt, Roland Favier, Guido Ferretti, DominiqueDesplanches, Hilde Spielvogel, Harry Koubi, Brigitte Sempore, and HansHoppeler. Lactate and epinephrine during exercise in altitudenatives. J. Appl. Physiol. 81(6):2488-2494, 1996.We tested the hypothesis that the reported lowblood lactate accumulation ([La]) during exercise inaltitude-native humans is refractory to hypoxia-normoxia transitions byinvestigating whether acute changes in inspiredO₂ fraction(FI_O2) affect the[La] vs. power output ()relationship or, alternatively, as reported for lowlanders, whetherchanges in [La] vs. on changes inFI_O2 are related tochanges in blood epinephrine concentration ([Epi]). Altitude natives [n = 8, age 24 ± 1 (SE) yr, body mass 62 ± 3 kg, height 167 ± 2 cm]in La Paz, Bolivia (3,600 m) performed incremental exercise with twolegs and one leg in chronic hypoxia and acute normoxia (AN). Submaximalone- and two-leg O₂ uptake (O₂) vs. relationships were not altered byFI_O2. AN increased two-legpeak O₂ by 10% and peak by 7%. AN paradoxically decreasedone-leg peak O₂ by 7%,whereas peak remained the same. The[La] vs. relationships were similar tothose reported in unacclimatized lowlanders. There was a shift to theright on AN, and maximum [La] was reduced by 7 and 8% forone- and two-leg exercises, respectively. [Epi] and[La] were tightly related (mean r = 0.81) independently ofFI_O2. Thus normoxiaattenuated the increment in both [La] and [Epi]as a function of , whereas the correlation between[La] and [Epi] was unaffected. These data suggest loose linkage of glycolysis to oxidative phosphorylation under influence from [Epi]. In conclusion, high-altitudenatives appear to be not fundamentally different from lowlanders with regard to the effect of acute changes inFI_O2 on [La] during exercise.

     

Influence of Androgenicity on Adipocytes and Precursor Cells in Female Rats

We examined the effects of overexposure of testosterone (T) on fat cell morphology and adipocyte precursor pools in inguinal and retroperitoneal fat depots of ovariectomized rats. In both tissues peripubertal T decreased weights without affecting adipocyte mean cell size or the size distribution profiles, but adipocyte number was decreased by 65% in the inguinal and by 38% in the retroperitoneal depots. Immunofluorescent flow cytometry utilizing a specific antibody to rat adipose tissue lipoprotein lipase was used to quantify regional precursor cell populations. T sharply reduced the percentages of differentiated and undifferentiated preadipocytes in the inguinal depot, from 43.2 ± 5.3 to 23.5 ± 2.1% and from 57.7 ± 4.0 to 43.6 ± 5.3%, respectively, with a concomitant increase in fibroblasts from 1.6 to 32.9%. On the other hand, T had no effect on retroperitoneal preadipocyte pools. Perinatal andro-genization exacerbated the decline in the inguinal weight (1.4 ± 0.1 vs. 2.2 ± 0.1g) but otherwise did not influence the actions of peripubertal T. Androgens may thus act in a tissue-specific manner to regulate fat cell growth potential in the femoral region in the female.     

Socioeconomic determinants of rates of consultation in general practice based on fourth national morbidity survey of general practices.

OBJECTIVE--To identify the socioeconomic determinants of consultation rates in general practice. DESIGN--Analysis of data from the fourth national morbidity survey of general practices (MSGP4) including sociodemographic details of individual patients and small area statistics from the 1991 census. Multilevel modelling techniques were used to take account of both individual patient data and small area statistics to relate socioeconomic and health status factors directly to a measure of general practitioner workload. RESULTS--Higher rates of consultations were found in patients who were classified as permanently sick, unemployed (especially those who became unemployed during the study year), living in rented accommodation, from the Indian subcontinent, living with a spouse or partner (women only), children living with two parents (girls only), and living in urban areas, especially those living relatively near the practice. When characteristics of individual patients are known and controlled for the role of "indices of deprivation" is considerably reduced. The effect of individual sociodemographic characteristics were shown to vary between different areas. CONCLUSIONS--Demographic and socioeconomic factors can act as powerful predictors of consultation patterns. Though it will always be necessary to retain some local planning discretion, the sets of coefficients estimated for individual level factors, area level characteristics, and for practice groupings may be sufficient to provide an indicative level of demand for general medical services. Although the problems in using socioeconomic data from individual patients would be substantial, these results are relevant to the development of a resource allocation formula for general practice.