Systematics within Gyps vultures: a clade at risk

Background  

Populations of the Oriental White-backed Vulture (Gyps bengalensis) have declined by over 95% within the past decade. This decline is largely due to incidental consumption of the non-steroidal anti-inflammatory veterinary pharmaceutical diclofenac, commonly used to treat domestic livestock. The conservation status of other Gyps vultures in southern Asia is also of immediate concern, given the lack of knowledge regarding status of their populations and the continuing existence of taxonomic uncertainties. In this study, we assess phylogenetic relationships for all recognized species and the majority of subspecies within the genus Gyps. The continuing veterinary use of diclofenac is an unknown but potential risk to related species with similar feeding habits to Gyps bengalensis. Therefore, an accurate assessment of the phylogenetic relationships among Gyps vultures should aid in their conservation by clarifying taxonomic uncertainties, and enabling inference of their respective relatedness to susceptible G. bengalensis.     

Patterns of divergence during evolution of alpha 1-proteinase inhibitors in mammals

alpha 1-Proteinase inhibitor (alpha 1-PI), a member of the serine proteinase inhibitor superfamily, has a primary role in controlling neutrophil elastase activity within the mammalian circulation. Several studies have indicated that the reactive center region of alpha 1-PI, the amino acid sequence of which is critical to recognition of and binding to target proteinases, is highly divergent within and among species. This appears to be a consequence of accelerated rates of evolution that may have been driven by positive Darwinian selection. In order to examine this and other features of alpha 1-PI evolution in more detail, we have isolated and sequenced cDNAs representing alpha 1- PI mRNAs of the mouse species Mus saxicola and Mus minutoides and have compared these with a number of other mammalian alpha 1-PI mRNAs. Relative to other mammalian mRNAs, the extent of nonsynonymous substitution is generally high throughout the alpha 1-PI mRNA molecule, indicating greater overall rates of amino acid substitution. Within and among mouse species, the 5'-half of the mRNA, but not the 3'-half, has been homogenized by concerted evolution. Finally, the reactive center is under diversifying or positive Darwinian selection in murid rodents (rats, mice) and guinea pigs yet is under purifying selection in primates and artiodactyls. The significance of these findings to alpha 1-PI function and the possible selective forces driving evolution of serpins in general are discussed.      

Mitochondrial DNA polymorphisms in subterranean mole-rats of the Spalax ehrenbergi superspecies in Israel, and its peripheral isolates

Patterns of mitochondrial DNA (mtDNA) variation were examined in 133 mole-rats constituting all four chromosomal species (2n = 52, 2n = 54, 2n = 58, and 2n = 60) of the Spalax ehrenbergi superspecies in Israel, as well as the peripheral isolates of 2n = 60. In the main range of the complex, a total of 28 mtDNA haplotypes were found in 64 mole-rats, with most haplotypes being unique to either a single chromosomal species or population. mtDNA divergence increased from low to high diploid number in a north-to-south direction in Israel. Overall levels of mtDNA diversity were unexpectedly the highest in the 2n = 60, the youngest species of the complex. The mtDNA haplotypes can be separated into two major groups, 2n = 52-54 and 2n = 58-60, and a phylogenetic analysis for each group revealed evidence of a few haplotypes not sorted by diploid number. The overall patterns of mtDNA divergence seen within and among the four chromosomal species are consistent with the parapatric mode of speciation as suggested from previous studies of allozyme and DNA hybridization. In a separate data set the patterns of mtDNA variation were examined across the main geographic range and across peripheral semi-isolates and isolates of the 2n = 60 chromosomal species. Fifteen haplotypes were found in 69 mole-rats. High levels of mtDNA diversity characterized the main range, semi-isolated, and even some desert isolated populations. The peripheral isolates contain much mtDNA diversity, including novel haplotypes.      

Relevance of IGF-I, IGFBP-3, and IGFBP-2 measurements during GH treatment of GH-deficient and non-GH-deficient children and adolescents

BACKGROUND: Little information is available on the relevance of parameters representing the insulin-like growth factor (IGF) system with regard to growth hormone (GH) treatment during childhood. In adults, high IGF-I levels were found to be associated with side effects and long-term risks. AIM/METHOD: Our aim was to monitor the serum levels of IGF-I, IGF-binding protein (IGFBP) 3, and IGFBP-2 during long-term GH treatment of 156 patients with GH deficiency (GHD) and of 153 non-GHD patients. We determined the extent to which the IGF parameters exceed the normal ranges and identified those parameters which are predictive of 1st-year growth. RESULTS: In prepubertal GHD children, the levels of IGF-I, IGFBP-3, and IGF-I/IGFBP-3 exceeded the 95th centile of the reference values for this age group in 2.3, 0.3, and 7.9% of the cases, respectively, whereas in prepubertal non-GHD children, the same parameters exceeded the 95th reference centile in 20.1, 3.5, and 32.2%, respectively. In pubertal GHD children IGF-I, IGFBP-3, and IGF-I/IGFBP-3 levels exceeded the 95th reference centile in 11.1, 1.5, and 15.4%, respectively. In pubertal non-GHD children, these levels also exceeded the 95th centile in 26.7, 7.0, and 41.4%, respectively. In both GHD and non-GHD groups, however, some patients had IGF parameters which were below the reference values. Our analysis showed that, in both groups, in addition to maximum GH, all IGF parameters (IGF-I, IGFBP-3, IGF-I/IGFBP-3 ratio, IGFBP-2 or derivatives) significantly extend the scope of a calculated model for predicting 1st-year height velocity. CONCLUSION: For reasons of safety and optimization of GH therapy, it is essential to follow up IGF-I, IGFBP-3, and IGFBP-2 levels regularly during childhood.     

Experience with growth hormone therapy in Turner syndrome in a single centre: low total height gain, no further gains after puberty onset and unchanged body proportions

The experience gained since 1987, through observation of 85 girls with Turner syndrome under growth hormone (GH) treatment, has enabled the analysis of one of the largest cohorts. Our results show that age, karyotype and height reflect the heterogeneity of the patients examined at our growth centre. In 47 girls, followed over 4 years on GH (median dose 0.72 IU/kg/week), the median age was 9.4 years and mean height SDS was -3.55 (Prader) and -0.14 (Turner-specific), while height and other anthropometrical parameters [weight, body mass index, sitting height (SH), leg length (LL) SH/LL, head circumference, arm span] were documented and compared to normative data as well as to Turner-specific references established on the basis of a larger (n = 165) untreated cohort from Tübingen. The latter data are also documented in this article. Although there was a trend towards normalization of these parameters during the observation period, no inherent alterations in the Turner-specific anthropometric pattern occurred. In 42 girls who started GH treatment at a median age of 11.8 years, final height (bone age >15 years) was achieved at 16.7 years. The overall gain in height SDS (Turner) from start to end of GH therapy was 0.7 (+/- 0.8) SD, but 0.9 (+/- 0.6) SD from GH start to onset of puberty (spontaneous 12.2 years, induced 13.9 years) and -0.2 (+/- 0.8) from onset of puberty to end of growth. Height gain did not occur in 12 patients (29%) and a gain of > 5 cm was only observed in 16 patients (38%). Height gain correlated positively with age at puberty onset, duration, and dose of GH, and negatively with height and bone age at the time GH treatment started. Final height correlated positively with height SDS at GH start and negatively with the ratio of SH/LL (SDS). We conclude that, in the future, GH should be given at higher doses, but oestrogen substitution should be done cautiously, owing to its potentially harmful effect on growth. LL appears to determine height variation in Turner syndrome and the potential to treat short stature successfully with GH.