Patterns of differentiation and hybridization in North American wolflike canids, revealed by analysis of microsatellite loci

Genetic divergence and gene flow among closely related populations are difficult to measure because mutation rates of most nuclear loci are so low that new mutations have not had sufficient time to appear and become fixed. Microsatellite loci are repeat arrays of simple sequences that have high mutation rates and are abundant in the eukaryotic genome. Large population samples can be screened for variation by using the polymerase chain reaction and polyacrylamide gel electrophoresis to separate alleles. We analyzed 10 microsatellite loci to quantify genetic differentiation and hybridization in three species of North American wolflike canids. We expected to find a pattern of genetic differentiation by distance to exist among wolflike canid populations, because of the finite dispersal distances of individuals. Moreover, we predicted that, because wolflike canids are highly mobile, hybrid zones may be more extensive and show substantial changes in allele frequency, relative to nonhybridizing populations. We demonstrate that wolves and coyotes do not show a pattern of genetic differentiation by distance. Genetic subdivision in coyotes, as measured by theta and Gst, is not significantly different from zero, reflecting persistent gene flow among newly established populations. However, gray wolves show significant subdivision that may be either due to drift in past Ice Age refugia populations or a result of other causes. Finally, in areas where gray wolves and coyotes hybridize, allele frequencies of gray wolves are affected, but those of coyotes are not. Past hybridization between the two species in the south-central United States may account for the origin of the red wolf.      

Fold-recognition and comparative modeling of human α2,3-sialyltransferases reveal their sequence and structural similarities to CstII from Campylobacter jejuni

Background  

The 3-D structure of none of the eukaryotic sialyltransferases (SiaTs) has been determined so far. Sequence alignment algorithms such as BLAST and PSI-BLAST could not detect a homolog of these enzymes from the protein databank. SiaTs, thus, belong to the hard/medium target category in the CASP experiments. The objective of the current work is to model the 3-D structures of human SiaTs which transfer the sialic acid in α2,3-linkage viz., ST3Gal I, II, III, IV, V, and VI, using fold-recognition and comparative modeling methods. The pair-wise sequence similarity among these six enzymes ranges from 41 to 63%.     

Quantitative evaluation of cell orientation in culture.

A quantitative method to assess mutual orientation of cells in cultures on a substrate includes the following operations: (1) the cellular groups to be evaluated are chosen; (2) position of the long axis for each nucleus of the group is determined; (3) the axis OX is arbitrary chosen for every group and the angles alphai between the long axis of every nucleus i and the axis OX are measured. Every nucleus i corresponds to a vector of unit length ei with the angles 2alpha. D, the mean of the vectors ei for every cell group is calculated. This value of D is compared with a set of values of D computed according to a model of mutual orientation studies in a simulation experiment. In this model the group of n vectors consists of a fraction of Kn parallel vectors (o less than or equal to K less than or equal to I) and of (I minus K)n randomly oriented vectors. K corresponding to the computed D which is equal to the experimental value of D is considered as an index of orientation for the group. Contact orientation with respect to the relief of the substrate may be evaluated as a root mean square deviation sigma0 to the angles between the long axes of cell nuclei and the direction of relief. Examples of the measurements of K and sigma0 in cell cultures are given.     

Hypoxic preconditioning modifies activity of pro- and antioxidant systems in the rat hippocampus

The effects of repetitive mild hypobaric hypoxic preconditioning on pro- and antioxidant systems in rat hippocampus have been studied. It was found that three-trial preconditioning by mild hypobaric hypoxia (360 mm Hg, 2 h) induced moderate oxidative stress immediately after the last preconditioning trial. In addition, it down regulated the levels of protein antioxidants (Trx-1, Trx-2, Cu,Zn-SOD) and also decreased several lipid peroxidation products 24 h after the preconditioning.     

Involvement of calcium-binding membrane components in neurophysiological mechanics of habituation in Helix pomatia

Dynamics of binding between calcium and hydrophobic membrane components were investigated in vivo in identified neurons ofHelix pomatia while producing habituation to tactile stimuli using a fluorescent chlortetracycline probe technique. A decline in the concentration of membrane-bound calcium (Ca _b ²⁺ ) and likewise in the intensity of electrophysiological response was found in the "command" neurons of defensive behavior when applying a train of stimuli. An increase in Ca _b ²⁺ was noted in the sensory neuron studied and in the spiracle motoneurons. It proved difficult to produce habituation in these cells fulfilling standard electrophysiological criteria. Hydrophobe-hydrophil transfer of calciumbinding molecules is thought to accompany production of habituation in nerve cells.P. K. Anokhin Institute of Normal Physiology, Academy of Medical Sciences of the USSR, Moscow. I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 21, No. 5, pp. 605–612, September–October, 1989.     

Antifilarial and Antibiotic Activities of Methanolic Extracts of Melaleuca cajuputi Flowers

We evaluated the activity of methanolic extracts of Melaleuca cajuputi flowers against the filarial worm Brugia pahangi and its bacterial endosymbiont Wolbachia. Anti-Wolbachia activity was measured in worms and in Aedes albopictus Aa23 cells by PCR, electron microscopy, and other biological assays. In particular, microfilarial release, worm motility, and viability were determined. M. cajuputi flower extracts were found to significantly reduce Wolbachia endosymbionts in Aa23 cells, Wolbachia surface protein, and microfilarial release, as well as the viability and motility of adult worms. Anti-Wolbachia activity was further confirmed by observation of degraded and phagocytized Wolbachia in worms treated with the flower extracts. The data provided in vitro and in vivo evidence that M. cajuputi flower extracts inhibit Wolbachia, an activity that may be exploited as an alternative strategy to treat human lymphatic filariasis.     

Effect of Moringa oleifera leaves on hematological profile of fluorosis affected rats

Fluorosis is a metabolic disease that is endemic in nearly 25 countries with India being one of the most affected. It primarily affects the bone and the teeth. Moringa oleifera (MO) leaves are known to reduce the effect of fluorosis on various tissues. Therefore, it is of interest to document the effect of Moringa oleifera leaves on the hematological profile of fluorosis affected rats. Twenty four Sprague Dawley rats were housed two per cage in a room with 12 hours light and 12 hours dark cycle. The rats were allowed to adjust to the laboratory environment for about one to two weeks before the beginning of the study. This study reveals that MO leaves is effective in reducing the plasma fluoride content. It also helps in improving the Hb % and RBC count in fluorosis affected rats. Data shows that Moringa olifera leaves powder is effective in reducing the plasma fluoride content. It also helps in improving the Hemoglobin percentage & Red Blood Cell count in fluorosis affected rats.     

Atlas – a data warehouse for integrative bioinformatics

Background  

We present a biological data warehouse called Atlas that locally stores and integrates biological sequences, molecular interactions, homology information, functional annotations of genes, and biological ontologies. The goal of the system is to provide data, as well as a software infrastructure for bioinformatics research and development.