Fetal ultrasonography: biometric data from four African primate species

BACKGROUND: Nonhuman primates are raised in large numbers in research centers and zoos. Reproductive monitoring is required to improve breeding performances. Ultrasonography is a safe method to determine gestational age and to estimate the date of parturition. However only few data are available in nonhuman primates. METHODS: Fetal biometric data were obtained throughout pregnancy on four African primate species, namely chimpanzee, gorilla, mandrill and patas monkey. Measurements included biparietal diameter, transverse abdominal diameter, femur and humerus length, external interorbital diameter, and fetal heart rate. Curves established from these data were compared with previously published data in chimpanzees and gorillas and with those for humans and other closely related primate species. RESULTS: The curves for the different hominids were very similar, while those for mandrills more closely resembled baboons and data for patas monkeys were comparable to those for macaques. CONCLUSIONS: These data, by providing a tool to evaluate precise gestational age, will be useful for centers raising these four primate species.     

High genetic diversity and no inbreeding in the endangered copper redhorse, Moxostoma hubbsi (Catostomidae, Pisces): the positive sides of a long generation time

The evolutionary potential of a species is determined by its genetic diversity. Thus, management plans should integrate genetic concerns into active conservation efforts. The copper redhorse (Moxostoma hubbsi) is an endangered species, with an endemic distribution limited to the Richelieu River and a short section of the St Lawrence River in Quebec, Canada. The population, gradually fragmented since 1849, is characterized by a decline in population size and a lack of recruitment. A total of 269 samples were collected between 1984 and 2004 and genotyped using 22 microsatellite loci, which indicated that these fish comprise a single population, with a global F(ST) value of only 0.0038. Despite a small census size ( approximately 500), a high degree of genetic diversity was observed compared to common values for freshwater fishes (average number of 12.5 alleles/locus and average HO of 0.77 +/- 0.08). No difference was observed between expected and observed pairwise values of relatedness (r(xy): -0.00013 +/- 0.11737), suggesting an outbred population. Long-term Ne was estimated at 4476 whereas contemporary Ne values ranged from 107 to 568, suggesting a pronounced yet gradual demographic decline of the population, as no bottleneck could be detected for the recent past. By means of simulations, we estimated Ne would need to remain at more than approximately 400 to retain 90% of the genetic diversity over 100 years. Overall, these observations corroborate other recent empirical studies confirming that long generation times may act as a buffering effect contributing to a reduction in the pace of genetic diversity erosion in threatened species.     

Design and synthesis of novel imidazoline derivatives with potent antihyperglycemic activity in a rat model of type 2 diabetes

Imidazoline derivatives have been reported to show antihyperglycemic activity in vivo. In the present study, we first showed that there was no correlation between the in vivo antidiabetic activity and the in vitro affinities for the I1/I2 binding sites for several substituted aryl imidazolines. Among these compounds, 2-(alpha-cyclohexyl-benzyl)-4,5-dihydro-1H-imidazole 2 exhibited potent antihyperglycemic properties. It was then chosen as lead compound. Thirty-six new derivatives were synthesized by replacing the cyclohexyl/benzyl group by various cyclic systems or the imidazoline ring by isosteric heterocycles. These compounds were evaluated in vivo for their antihyperglycemic activity using an oral glucose tolerance test (OGTT) in a rat model of type-2 diabetes obtained by giving a single intravenous (iv) injection of a low dose of streptozotocin to rats (STZ rats) and in normal rats. Nine compounds with an imidazoline moiety, possibly substituted by a methyl group, had a potent effect on the glucose tolerance in normal or STZ-diabetic rats, after an oral (po) administration of the test compound at a dose of 30 or 10 mg kg(-1), without any hypoglycemia. Replacement of the imidazoline ring by isosteric heterocycles resulted in a total loss of activity.     

Spirocyclopropyl pyrrolidines as a new series of alpha-L-fucosidase inhibitors

Polyhydroxy 4-azaspiro[2.4]heptane derivatives (spirocyclopropyl iminosugars) were prepared in four to six steps from readily available protected aldoses. The key step of the reaction sequence involves a titanium-mediated aminocyclopropanation of glycononitriles with subsequent cyclization. Five new polyhydroxypyrrolidines so-obtained have been evaluated for their ability to inhibit 16 glycosidases. One of them exhibits selective inhibition of alpha-L-fucosidase from bovine kidney (Ki=1.6 microM, competitive).     

Search for alpha-glucosidase inhibitors: new N-substituted valienamine and conduramine F-1 derivatives

A solid-phase synthesis of new N-substituted valienamines has been developed and new synthesis of (+/-)-conduramine F-1, (-)-conduramine F-1, and (+)-ent-conduramine F-1 is presented, together with the preparation of N-benzylated conduramines F-1. N-Benzylation of both valienamine and (+)-ent-conduramine F-1 improves their inhibitory activity toward alpha-glucosidases significantly. The additional hydroxymethyl group makes valienamine derivatives more active than their (+)-ent-conduramine F-1 analogues.     

Conformational modifications of alpha gliadin and globulin proteins upon complex coacervates formation with gum Arabic as studied by Raman microspectroscopy

As a molecular model of gelatin-free coacervates, complexes of pea globulin and alpha gliadin proteins with gum arabic prepared at different acidic pH values are studied using Raman microspectrometry. Raman spectra confirm higher content of beta-sheets and random coils in pea globulin and dominating alpha-helical structures in alpha gliadin. For protein-gum arabic complexes, Raman data support the existence of specific pH conditions for optimal complex coacervation (pH 2.75 for globulin and pH 3.0 for gliadin(1)), when (i) pH-induced conformational perturbations of free protein structure are the strongest and (ii) compensation of these perturbations by gum arabic is the most pronounced. Conformations implied in the protein-gum complexes are mainly beta-sheets in pea globulin and alpha-helix in alpha gliadin. The role of electrostatic and non-Coulombic interactions (intermolecular hydrogen bonds) in stabilizing of protein-polysaccharide complexes is discussed in relation with the overall structure and the charge density profile of these two proteins.     

Does disturbance and restoration of alpine grassland soils affect the genetic structure and diversity of bacterial and N2-fixing populations?

Responses of bacterial communities to disturbance and restoration processes were investigated on alpine grassland soil. Bulk soil, rhizosphere soil and two soil separates, i.e. sand-size (2000-200 microm) and silt-size (50-2 microm) were sampled from undisturbed grassland soil to soil under restoration for 1 month, 1 year, 4 years and 13 years after disturbance. Automated ribosomal intergenic spacer analysis (ARISA) and restriction fragment length polymorphism (RFLP) of nifH gene pools were used to assay genetic structure of the bacterial communities and N2-fixing guild. According to the distribution of ARISA band length in bacterial phyla, the dominance of ARISA bands below 400 bp showed that Gram-positive bacteria would be predominant in the studied grassland soil when not disturbed. Disturbance affected the genetic structure of bacterial community and of N2-fixing guild in relation to their location within the selected habitats. Shifts in IGS and nifH profiles of bulk soil metagenome were larger than those observed from sand-size- and silt-size-fractions, accounting for 40-50% of the variance in the profiles. Restoration of the genetic structure of telluric bacteria community and N2-fixing populations was found to be influenced by the spatial heterogeneity of the soil and niche diversification. Particular bacterial genetic structure within distinct habitats were evidenced and must be defined as subdivisions of the meta-community of bulk soil. Scale of soil microbial diversity/stability relationships is discussed with special attention to disconnected bacterial habitat compared with whole soil with multiple niches.