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B S Gill

Publications and source records attributed to B S Gill.

At least 73 records · Page 4Linked to original sources
PubMed1994

Different species-specific chromosome translocations in Triticum timopheevii and T. turgidum support the diphyletic origin of polyploid wheats.

Triticum timopheevii ssp. timopheevii and T. timopheevii ssp. araraticum were analysed by sequential N-banding and genomic in situ hybridization. Three chromosomes, 6At, 1G and 4G, were involved in At-G intergenomic translocations in all six lines analysed. These chromosomes may be derived from a cyclic translocation that is species-specific to T. timopheevii. In contrast, Triticum turgidum has a species-specific cyclic translocation involving chromosomes 4A, 5A and 7B. The discovery of different species-specific chromosome translocations supports the diphyletic hypothesis of the evolution of tetraploid wheats. The results from genomic blocking analysis also revealed that the chromosomes of Aegilops speltoides are closer to the G genome than the B genome chromosomes. The possible role of species-specific translocations in the evolution of wheat is discussed.

Chromosome Banding↗
PubMed1993

A 'zebra' chromosome arising from multiple translocations involving non-homologous chromosomes.

An alloplasmic wheat line carrying a 'zebra' chromosome z5A was isolated from the derivatives of an Elymus trachycaulus x Triticum aestivum cv Chinese Spring hybrid. Chromosome z5A was named zebra because of its striped genomic in situ hybridization pattern. z5A consists of four chromosome segments derived from E. trachycaulus and four chromosome segments, including the centromere, from wheat. The short arm of z5A paired with the telocentric chromosome 1H(t)S of E. trachycaulus and the long arm with the long arm of normal 5A. z5A also carried several genetic markers derived from 1H(t)S. Chromosome 1H(t) was the only E. trachycaulus chromosome found in the sib plants of a previous generation from which z5A was derived. Monosomic 5A and telocentric chromosome 5AL were also found in most of the sib plants. The zebra chromosome most probably originated from spontaneous multiple translocations between chromosomes 5A and 1H(t)S or 5A and 1H(t).

Chromosome Banding↗
PubMed1993

Fine physical mapping of Ph1, a chromosome pairing regulator gene in polyploid wheat.

The diploid-like chromosome pairing in polyploid wheat is controlled by the Ph1 (pairing homoeologous) gene that is located on chromosome arm 5BL. By using a combination of cytogenetic and molecular techniques, we report the physical location of the Ph1 gene to a submicroscopic chromosome region (Ph1 gene region) that is flanked by the breakpoints of two deletions (5BL-1 and ph1c) and is marked by a DNA probe (XksuS1). The Ph1 gene region is present distal to the breakpoint of deletion 5BL-1 but proximal to the C-band 5BL2.1. Two other DNA probes (Xpsr128 and Xksu75) flank the region-Xpsr128 being proximal and Xksu75 being distal. The estimated size of the region is less than 3 Mb. The chromosome region around the Ph1 gene is high in recombination as the genetic distance of the region between 5BL-1 breakpoint and C-band 5BL2.1 (not resolved by the microscope) is at least 9.3 cM.

Chromosome Banding↗
PubMed1992

Toward a cytogenetically based physical map of the wheat genome.

Bread wheat (Triticum aestivum L. em Thell) is well suited for cytogenetic analysis because the genome, buffered by polyploidy, can tolerate structurally and numerically engineered chromosomes for analysis over infinite generations. This feature of polyploidy can be used in developing a high-resolution, cytogenetically based physical map of the wheat genome. We show that numerous deletions, observed in the progeny of a monosomic addition of a chromosome from Triticum cylindricum in wheat, result from single breakpoints and a concomitant loss of distal fragments. Breakages occurred in euchromatic and heterochromatic regions. Forty-one deletions for chromosomes 7A, 7B, and 7D, and a set of genetically mapped DNA probes, were used to construct physical maps. Recombination was low in proximal chromosomal regions and very high toward the distal ends. Deletion mapping was more efficient than genetic mapping in resolving the order of proximal loci. Despite variation in size and arm ratio, relative gene position was largely conserved among chromosomes 7A, 7B, and 7D and a consensus group 7 physical map was constructed. Several molecularly tagged chromosome regions (MTCRs) of approximately one to a few million base pairs were identified that may be resolved by long-range mapping of DNA fragments. Thus, a cytogenetically based physical map may be used to integrate chromosome and DNA-based maps. The MTCRs may simplify strategies for cloning of agronomically useful genes despite the genetic complexity and the large genome size of wheat.

Blotting, Southern↗
PubMed1992

Application of the Tradescantia micronucleus assay for the genetic evaluation of chemical mixtures in soil and aqueous media.

Genotoxic evaluations of arsenic trioxide, dieldrin, lead tetraacetate and their nine binary and one tertiary mixtures were performed using the Tradescantia micronucleus (Trad-MN) assay. The chemicals or their mixtures were either (1) mixed into soil, and chemical exposure to the target cells was through the roots of intact plants grown in the soil or (2) through plant cuttings in which the inflorescences received treatment by absorption through stem of an aqueous solution of the test chemicals. All three chemicals yielded clastogenic responses when tested in soil medium and only two of these i.e. arsenic trioxide and dieldrin were positive when plant cuttings were exposed to the test chemicals in the aqueous medium. The clastogenicity of the chemical mixtures was modified by the ratio of the individual chemical in a particular mixture and also by the medium in which these mixtures were tested.

Arsenic↗
PubMed1992

In vivo monastral blue-induced lamellar-bodies in lysosomes of pulmonary intravascular macrophages (PIMs) of bovine lung: implications of the surface coat.

We previously reported that the pulmonary intravascular macrophages (PIMs) of sheep, goat, and calf lung contained a heparin and a lipolytic lipase sensitive surface coat by using tannic acid as a component of paraformaldehyde-glutaraldehyde-based fixative. The implication of this sensitivity was that the surface coat was predominantly comprised of lipoprotein-like substance. In this study we report that monastral blue (MB) used as a vascular tracer interacted with the coat globules and lost its original particulate appearance. Its precise localization in the PIMs was in combination with altered macromolecules of the surface coat in the form of lipid droplets, which conformed to the conventional view of neutral lipids. In contrast, pigment particles examined in their native state resembled metallic particles as electron-dense elliptical rods. The lipid droplets were subsequently internalized through endocytic route and found their access into the lysosomal compartments of PIMs at the electron microscopic level. Lamellar bodies (LLBs) arose from the lysosomal matrix after the entry of lipid droplets in the secondary lysosomes. Acid phosphatase activity was located in secondary lysosomes as well as in endosomes. These observations suggest that coat granules of the PIMs acted as a carrier of exogenous MB particles to deliver the complex to the lysosomal compartment where partial digestion lead to the formation of lamellar bodies. The implications of MB (cationic dye) as a vascular tracer for studying phagocytic index of PIMs in the light of their coat and the rapid development of LLBs are discussed. It is proposed that MB by initially combining with the surface coat provokes mobilization of intracellular lipid pools. In this way metabolism of vasoactive lipid in the PIMs is stimulated to influence the dynamics of pulmonary circulation in the calves.

Acid Phosphatase↗
PubMed1991

Treatment of stephanofilariosis ('earsore') with ivermectin.

Thirty-four adult male buffaloes with clinical signs of 'earsore' were used to determine the efficacy of ivermectin against Stephanofilaria zaheeri. On the basis of parasite counts in skin scrapings, ivermectin was effective as a microfilaricide. Adult parasite counts were reduced, but removal of adults was incomplete. Clinical improvement was recorded in more than half of the treated buffaloes, but constant reinfection meant that meaningful interpretations were not possible.

Animals↗
PubMed1991

A DNA fragment mapped within the submicroscopic deletion of Ph1, a chromosome pairing regulator gene in polyploid wheat.

Bread wheat is an allohexaploid consisting of three genetically related (homoeologous) genomes. The homoeologous chromosomes are capable of pairing but strict homologous pairing is observed at metaphase 1. The diploid-like pairing is regulated predominantly by Ph1, a gene mapped on long arm of chromosome 5B. We report direct evidence that a mutant of the gene (ph1b) arose from a submicroscopic deletion. A probe (XksuS1-5) detects the same missing fragment in two independent mutants ph1b and ph1c and a higher intensity fragment in a duplication of the Ph1 gene. It is likely that XksuS1-5 lies adjacent to Ph1 on the same chromosome fragment that is deleted in ph1b and ph1c. XksuS1-5 can be used to tag Ph1 gene to facilitate incorporation of genetic material from homoeologous genomes of the Triticeae. It may also be a useful marker in cloning Ph1 gene by chromosome walking.

Blotting, Southern↗
PubMed1991

Evaluation of 10 chemicals for aneuploidy induction in the hexaploid wheat assay.

This study was a part of an international project sponsored by the Commission of the European Communities to evaluate the utility of certain bioassays including hexaploid wheat assay to identify potential aneugens. Ten suspect spindle poisons, i.e. colchicine (COL), cadmium chloride (CdCl2), chloral hydrate (CH), diazepam (DIZ), econazole (EZ), hydroquinone (HQ), pyrimethamine (PY), thiabendazole (TB), thimerosal (TM), and vinblastin sulphate (VBL) were tested for their ability to induce green and/or white leaf sectors as indicators of loss or gain of a chromosome respectively, in Neatby's strain of Chinese Spring wheat (2n = 6x = 42). All the chemicals tested in this study, with the exception of CH and HQ yielded positive response.

Aneuploidy↗
PubMed1989

Efficacy of ivermectin against mange and gastrointestinal nematodes of buffalo (Bubalus bubalis).

The incidence of mange in dairy buffalo in India has increased significantly in recent years. The authors record an outbreak of mange affecting a dairy herd stocking about 30,000 buffalo and 1000 cows. The mange mites were either Sarcoptes scabiei or Psoroptes ovis, or a mixed infestation of both. The morbidity rate was 5-30% varying from group to group, with 100% in a severely affected group. Signs noticed were progressive dermatitis, alopecia, keratinization, skin thickened and wrinkled, intense itching and marked loss of condition often ending in death. Great losses of young animals from mange and gastrointestinal nematodes are very common in dairy herds in India. In view of their economic importance, the activity of ivermectin against naturally occurring mange and parasitic infections of adult buffalo and buffalo calves was determined. Ivermectin was administered by subcutaneous injection (IVOMEC 1% w/v - MSD AGVET) at a dose of 200 mcg kg-1 body weight. The efficacy was ascertained from the disappearance of mites from skin scrapings and the reduction in numbers of worm eggs in the faeces. The results of the treatment were dramatic: the mites disappeared within 2 weeks of the drug being administered in the majority of animals, with marked improvement in skin lesions. Four buffalo which had their entire body surface affected with mange needed a second dose on Day 28 for complete recovery. The effect on the nematodes was equally spectacular, with infections of Neoascaris vitulorum, Trichostrongylidae, Oesophagostomum spp. and Bunostomum being eliminated within 1 week of treatment.

Animals↗
PubMed1987

Role of cytoplasm-specific introgression in the evolution of the polyploid wheats.

Studies of N-banded mitotic and meiotic karyotypes of Triticum turgidum L. (2n = 28; AABB) and Triticum timopheevii Zhuk. (2n = 28; AAGG) and hybrids between them, along with observations of meiotic pairing between telocentrics of the AB-genome chromosomes and their respective homologues and homeologues in T. timopheevii, showed that chromosome 4 (m4) of Triticum monococcum L. is present (as 4A(t)) in T. timopheevii but is lacking in T. turgidum. Neither 4A nor 4B pairs with 4A(t), but 4A pairs with 4G and, for this reason and because of its banding pattern, must be considered a B-genome chromosome. T. timopheevii chromosomes 4A(t) and 3A(t) are involved in a reciprocal translocation, and 2A(t), 1G, 2G, and 5G are also involved in translocations. Chromosome arm 4BL occasionally pairs with 7G. The satellites are on the short arms of chromosomes 6A(t) and 6G of T. timopheevii and 1B and 6B of T. turgidum. It is suggested that (i) T. timopheevii orginated as an allotetraploid of Aegilops speltoides Tausch/T. monococcum and (ii) T. turgidum was derived from T. timopheevii by introgressive hybridization with an unknown diploid species, which contributed its distinctive cytoplasm, chromosome 4B or a substantial portion of it, and additional chromosome segments. Rapid fixation of 4B in T. turgidum was ensured by cytoplasm-specific transmission.

Journal Article↗
PubMed1987

Comparative pathogenicity of Theileria annulata strains.

Twenty three susceptible crossbred calves were inoculated with five Indian strains of Theileria annulata, collected from natural cases of tropical theileriosis at Ludhiana, Hissar, Jaipur, Uruli-Kanchan and Bangalore. All the strains produced clinical disease with typical symptoms and lesions of acute theileriosis. The strains were considered highly virulent and equally pathogenic.

Animals↗
PubMed1984

Structural genes for alpha-amylases are located on barley chromosomes 1 and 6.

Genomic DNA from six euplasmic wheat-barley addition lines and from the wheat and barley parents were analyzed for the presence of alpha-amylase gene sequences, using plasmid DNAs from two different alpha-amylase cDNA clones as hybridization probes. Barley-specific alpha-amylase gene sequences were detected only in addition lines 1 and 6 carrying barley chromosomes 1 and 6, respectively. One cDNA clone probe hybridized strongly to sequences on chromosome 6 but not to those on chromosome 1. The other cDNA clone probe preferentially hybridized to sequences on chromosome 1. It is concluded that structural genes for alpha-amylases are located on barley chromosomes 1 and 6. alpha-Amylase genes on the same chromosome appear to be closely related to one another but substantially different from those on the other chromosome.

Chromosome Mapping↗