Effect of Magnetic Field on Chick Morphogenesis

It is well known that development of organisms, as well as normal functioning of different systems, is to a large extent affected by environmental factors. To study the effect of magnetic field on the chick morphogenesis, fresh fertilized eggs of White Leghorn were incubated to the definitive primitive streak stage [Hamburger-Hamilton (H.H.) stage 4]. The embryos were mounted on a watch glass using News in vitro culturing technique and then exposed to a homogeneous magnetic field of 5000 ± 200 Oe for 1 h. The controls were maintained simultaneously without the magnetic field. The experimental and control embryos were further incubated for 24 h so as to obtain the H.H. stage 12 in the controls. It was observed that experimental embryos were considerably retarded, as evidenced by shortening of the embryonic long axis and by other malformations. In 14 out of the 25 experimental embryos, the brain was poorly developed with open neural tube. In 18 of the 25 experimental embryos, the somites were diffused, and in 12 of the 25 experimental embryos, the heart was developed with slight displacement. All the controls developed normal to H.H. stage 12. Histological observations of the neural structures in the sectioned experimental embryos show increase in the number of dividing cells and their dispersed distribution throughout the neuroepithelium. The malformations recorded are attributed to the environmental stress effect caused by the magnetic field as manifested by its effect on mitotic activity, interkinetic nuclear migration in neuroepithelium and cell locomotion in general.     

Changes in leaf protein and pigment contents and photosynthetic activities during senescence of detached maize leaves: influence of different ultraviolet radiations

Senescence induced loss in pigments and proteins of detached maize (Zea mays L. cv. Col) leaves was significantly enhanced on the exposure of leaves to different ranges of ultraviolet (UV) radiation. Compared to UV-A (320-400 nm) and UV-B (280-320 nm), the UV-C (200-320 nm) was the most damaging for the pigments and macromolecules. A severe decline in photosystem (PS) 2 mediated photoreduction during senescence of detached leaves exposed to UV irradiation suggested a damage of the system. The PS1 mediated photoreduction of methylviologen with 2,6-dichlorophenol indophenol as electron donor was stimulated by UV-A and UV-B radiations, suggesting a reorganisation of the PS1 complex. These results were fortified by the values of fast and slow kinetics of chlorophyll (Chl) a fluorescence transients. This revised version was published online in June 2006 with corrections to the Cover Date.     

Development and characterization of genic SSR markers from low depth genome sequence of <Emphasis Type="Italic">Clarias batrachus</Emphasis> (magur)

Indian magur (Clarias batrachus) is an important freshwater catfish, which is listed as endangered under A3cde + 4acde ver. 3.1 categories by the IUCN (2015) due to decreasing population trend. Microsatellites or short sequence repeats (SSRs) tagged to genes have been utilized as gene marker. In the present study, 31,814 SSRs of C. batrachus (magur) were identified using microsatellite identification tool programme from the next generation sequencing data generated on Roche 454 and Ion Torrent platforms. A bioinformatics pipeline, with stringent criteria resulted in selection of 1672 microsatellite loci falling in the genic region. Initially, a total of 30 loci were selected for primer development; and of these 14 were successfully amplified and five were found to be polymorphic in 30 individuals of C. batrachus (magur). The observed as well as expected heterozygosity ranged from 0.038 to 0.526 and 0.434 to 0.784, respectively, and the number of observed alleles ranged from three to five. The study reported the application of next generation sequencing technologies for rapid development of microsatellite loci in Indian catfish species, C. batrachus (magur).     

Intrapopulation karyotypic variability in Allium roylei Stearn – a threatened species

Plants that are heterozygous for complex translocation from a small threatened population of Allium roylei Stearn from the Bani region of Jammu province (India) were analysed for karyotypic details. Somatic complements of all the plants analysed revealed heteromorphicity in one to three pairs of chromosomes. In addition, inter‐individual differences were observed regarding the presence or absence of one of the two nucleolar chromosomes, the positions that different heteromorphic chromosomal pairs occupy in the karyoidiograms and the extent of differences in various chromosomal pairs. The present paper records for the first time structural chromosomal polymorhism in A. roylei and highlights the probable mechanisms underlying the origin and establishment of this polymorphism. The extensive karyotypic variability seems to have originated through repeated interchanges involving a number of non‐homologous chromosomes. These anamolies are tolerated because there is no loss or gain of genes and, in addition, vegetative propagation is an efficient means of perpetuating the species. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 242–248.     

Rethinking inheritance,yet again: inheritomes,contextomes and dynamic phenotypes

Journal of Genetics -     

Six new species of Asphondylia (Diptera: Cecidomyiidae) damaging flower buds and fruit of Australian Acacia (Mimosaceae)

Six species of gall midge are described from Australian acacias. Asphondylia bursicola Kolesik sp.n. and A. occidentalis Kolesik sp.n . form galls on fruit; A. germinis Kolesik sp.n ., A. pilogerminis Kolesik sp.n . and A. glabrigerminis Kolesik sp.n . induce severe deformation of flower buds; and A. acaciae Kolesik sp.n . causes galls on both fruit and flower buds. Galled flower buds do not produce flowers, and galled fruit produce no or undeveloped seeds. Host ranges of the new species comprise between two and eight acacia hosts. Larval, pupal and male morphology, together with phylogenetic analyses of a 410‐bp fragment of the mitochondrial cytochrome b gene, were used to characterize the new species. For A. bursicola, A. germinis, A. pilogerminis, A. glabrigerminis and A. acaciae, the intraspecific divergence values were between 0.2 and 3.4%, and the interspecific divergence values ranged between 5.1 and 10.5%. For A. occidentalis, the only species with geographical distribution confined solely to Western Australia, the intraspecific divergence was between 6.6 and 10.3%, and the interspecific difference from the other five new species was between 9.3 and 13.9%. In contrast to Dasineura spp. from Acacia, for which the morphology was more informative in species recognition than the cytochrome b sequence, in Asphondylia spp. treated here the partial cytochrome b sequence data provided better species recognition than did the morphology. Several of the new Asphondylia have potential as biological control agents in ecosystems in which Australian acacias are invasive and their sexual reproduction needs to be restricted. A list of Australian acacias whose reproductive organs are destroyed by known gall midges, all belonging to Dasineura and Asphondylia, is provided.     

Accessory Chromosomes in a tree--Ficus krishnae

Accessory chromosomes in a tree, Ficus krishnae are reportedfor the first time. Besides the normal complement of 2n = 26;1–2 small euchromatic accessory chromosomes were encountered.The frequency of accessory chromosomes in somatic cells was30 per cent. In meiotic cells one accessory chromosome was presentin 54 per cent of cells while two were observed in 9 per centof the pollen mother cells.