Functional organization of polytene X-chromosome in two X-chromosome inversion carrying larvae of Drosophila melanogaster reared at 24°C or 10°C

Larvae of D. melanogasler carrying either the In(I)BM1 or In(I)BM2 inversion have been reared at 24° or at 10°C to study the morphology, transcription and replication of the X-chromosome in the salivary gland polytene nuclei. These two inversions share a similar left-hand breakpoint in euchromatin (16A 2-5 region in polytene X-chromosome) but have different right-hand breakpoints in the proximal heterochromatin. In 10°C reared BM1 male larvae, the polytene X appears somewhat more diffused than in 24°C reared larvae. On an average, in 36% of the polytene nuclei of 10°C reared BM2 male larvae the single X-chromosome appears considerably shortened in length, enlarged in width and has very indistinct band, while the other nucIei show "normal-looking" X as in BM1 larvae. This highly disorganized form of X-chromosome, referred to as "pompon-Iike" X, is never seen in cold-reared female or in warm-reared female as well as male BM2 or BM1 larvae. Hoechst 33258 fluorescence reveals that the "pompon-like" morphology of the X is due to loose packing of chromatin in different band regions. It is suggested that the "pompon-like" morphology is due to position effect variegation associated with the particular heterochromatin breakpoint in the BM2 inversion, 3H-uridine and 3H-thymidine labelling and autoradiography of polytene nuclei from cold-reared male and femal larvae of the two genotypes shows that the "pompon-like" or the "normal-looking" X in male nuclei continues its hyperactive transcription and faster replication as in 24°C reared wild-type larvae. It appears that the hyperactive organization of the hemizygous X in larval male polytene nuclei predisposes its pattern of chromatin condensation to be specifically affected by a variety of genetic, chemical and physical factors. However, the type of chromatin dispersion seen in "pompon-like" X in cold-reared BM2 male larvae does not seem to affect the basic functional (hyperactive) organization of the hemizygous X in male polytene nuclei

The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure

Fluorescence patterns of heterochromatin in mitotic and polytene chromosomes in seven members of three sub-groups of the melanogaster species group of Drosophila

A comparative study of fluorescence patterns of heterochromatin in mitotic and polytene chromosomes of seven species belonging to 3 subgroups melanogaster sub-group: D. melanogaster and D. simulans; montium sub-group: D. kikkawai and D. jambulina; ananassae sub-group: D. ananassae, D. malerkotliana and D. bipectinata) of the melanogaster species group of Drosophila (Sophophora) has been made. Hoechst 33258 (H) fluorescence patterns of mitotic chromosomes reveal differences correlated to the taxonomic groupings of these species. The melanogaster sub-group species have H-bright regions on heterochromatin of all chromosomes; the montium subgroup species have H-bright regions mainly on the 4th and Y-chromosomes; in the ananassae sub-group, while D. ananassae chromosomes do not show any H-bright regions, D. malerkotliana and D. bipectinata have small H-bright segments only on their 4th chromosomes. The H-and quinacrine mustard (QM) fluorescence patterns of larval salivary gland polytene chromocentre in these species, however, do not show the same taxonomic correlation. While D. ananassae and D. kikkawai polytene nuclei lack any H-or QMbright region in the chromocentre, the remaining species have prominent H-and/or QM-bright region(s). In D. jambulina, the QM-bright regions are generally bigger than H-bright regions, while in D. malerkotliana and D. bipectinata the situation is reversed. Actinomycin D counterstaining prior to H-staining of polytene preparations of each species confirms that the H-bright region/s in the chromocentre are composed of A-T rich sequences. In vivo labelling of salivary gland polytene nuclei with 5-bromodeoxyuridine for 24 to 48 h and subsequent H-staining reveals that in all the species, the H-bright regions do not replicate in 3rd instar stage and presumably represent the non-replicating alpha heterochromatin. Significantly, in all the species (excepting D. kikkawai and D. ananassae), the size, location and the number of H-and/or QM-bright regions were seen to vary in different polytene nuclei in the same gland. It seems that the organization and the extent of under-replication of alpha heterochromatin varies in different polytene nuclei. Present studies also show that even closely related species differ in the content and organization of H-bright heterochromatin. The 81 F band at the base of 3 R in D. melanogaster, but not in D. simulans, appears to contain non-replicating H-bright sequences in addition to replicating chromatin

Replication in Drosophila chromosomes. VII. Influence of prolonged larval life on patterns of replication in polytene chromosomes of Drosophila melanogaster

Prolongation of larval life in Drosophila melanogaster, by growing wild type larvae at lower temperature, or in animals carrying the X-linked mutation giant is known to result in a greater proportion of nuclei in salivary glands showing the highest level of polyteny. We have examined by autoradiography the patterns of 3H-thymidine incorporation during 10 rain or 1 rain pulses in salivary gland polytene chromosomes of older giant larvae and of wild type late third instar larvae of D. melanogaster grown since hatching either at 24°C or at 10°C. The various patterns of labelling and their relative frequencies are generally similar in glands from the warm- (24°C) or cold (10°C)-reared wild type larvae, except the interband (IB) labelling patterns which are very frequent in the later group but rare in the former. The IB type labelled nuclei in cold-reared wild type larvae show labelling ranging from only a few puffs/interbands labelled to nearly all puffs/interbands labelled. In warm-reared wild type larvae, very low labelled IB patterns are not seen. In older giant larvae, the 3H-thymidine labelling patterns are in most respects similar to those seen in cold-reared wild type larvae. In 1 rain pulsed preparations from all larvae, the IB patterns are relatively more frequent than in corresponding 10 rain pulsed preparations. No nuclei with the continuous (2C or 3C) type of labelling pattern, with all bands and interbands/puffs labelled, were seen in 1 rain pulsed preparations from cold-reared wild type or in giant larvae, and only a few nuclei in 1 rain pulsed preparations from warm-reared wild type larvae exhibited the 2C labelling pattern. Analysis of silver grain density on specific late replicating sites in late discontinuous (1D) type labelled nuclei suggests that the rate of DNA synthesis per chromosomal site is not different at the two developmental temperatures. It is suggested that correlated with the prolongation of larval life under cold-rearing conditions or in giant larvae, the polytene replication cycles are also prolonged. It is further suggested that the polytene S-period in these larvae is longer due to a considerable asynchrony in the initiation and termination of replication of different sites during a replication cycle

Replication in Drosophila chromosomes. Part VIII. Temporal order of replication of specific sites in polytene chromosomes from 24°C & 10°C reared larvae of D. melanogaster

D. melanogaster larvae has been grown at low (10°C) and usual (24°C) temperatures to study the effect of growth temperature of replication of specific replicating sites in polytene nuclei. In an earlier study [Mishra and Lakhotia. Chromosoma, 85 (1982) 221], we suggested that the polytene S-period in cold-reared larvae is prolonged due to a greater asynchrony in the initiation and replicating units of a nucleus, while the number of replicating units and their rate of replication remain similar. In the present study. replication of different replicating units in specific segments of X and 3L in polytene nuclei from 24 and 10°C reared larvae has been examined in detail. This analysis provides further evidence for identity of replicating units at two growth temperatures and for a greater asynchrony in replication of different sites at low growth temperature. The results also suggest that the temporal order of initiation and termination or replication of different units may vary in different nuclei within certain limits. Some aspects related to these are discussed

A Secure Software Engineering Perspective

Abstract- Software vulnerabilities are the prime cause for the cyber attacks and potential misuse of software applications. The vulnerabilities are mostly due to unsecure system architecture, software development language and design issues. Generally software development practice does not address these issues due to time-budget constraints and conflicting needs. This ultimately results in software development, where security is a major concern, remains mainly unnoticed. Secure software engineering by and large refers to the process of software security. The software security essentially focuses on developing the secure software, which generally depends on system architecture and software security assurance against the possible vulnerabilities. To address these issues, in this paper, a survey is reported as a state of art work in the areas of secure system architecture, buffer overflow attacks and confinement

Dosage compensation of X-chromosome activity in interspecific hybrids of Drosophila melanogaster and D. simulans

We have used the unstable ring X-chromosome of D. melanogaster to generate XX/XO mosaics in the hybrid progeny from crosses between D. melanogaster females and D. simulans males. The functional properties of the polytene X-chromosome(s) in salivary glands of such XO/XX mosaic hybrid larvae have been analysed by autoradiography after 3H-uridine or 3H-thymidine labelling of the glands. The simulans X-chromosome in the hybrid XO nuclei displays typical pale staining, enlarged diameter, higher rate of transcription (nearly two times higher than each of the Xs in the XX nuclei in the same gland) and a faster completion of replication as would be the case in the original parental XO or XY nuclei. In the hybrid XX polytene nuclei, the melanogaster as well as the simulans X functions in the same manner as in female cells of the parents. The nucleolar transcription is also equal in the hybrid XX and XO nuclei. Thus it seems that despite the evolutionary diversification between these two species, the regulatory system which brings about the dosage compensation of X-chromosome activity has been conserved

Search for Drosophila Genes based on Patterned Expression of Mini-White Reporter Gene of a P lacW Vector in Adult Eyes

Developmental expression of transduced mini-white(w) gene of Drosophila is sensitive to its flanking genomic enhancers. Taking advantage of this phenomenon, we mobilized a P lacW transposon and screened for new transposant lines which showed patterned expression of the mini-w gene in adult eyes. From a screen of about 1,000 independent P lacW transposant lines on the second chromosome, we identified 7 lines which showed patterned w expression in adult eyes. These P insertions were assigned to engrailed, wingless and teashirt genes based on their chromosomal locations, developmental expression of the lacZ reporter gene, lethal embryonic mutant phenotypes and, finally, their failure to complement the lethal alleles of the respective genetic loci. Our results show that although only a small fraction of the total transposant lines displayed patterned w expression, the genetic loci thus identified are those which play essential roles in pattern formation. Scopes of screens for genetic loci based on w reporter gene expression in adult eyes are discussed

Teaching aids and teaching methods in Neuro- Physiology: Views of Post graduate students

The present study was undertaken to evaluate the current teaching methods in Neuro- Physiology and to determine best teaching aid preferred by the students to implement and recommend to the teachers of physiology to make teaching more interesting and effective. The present cross sectional study was conducted in the Department of Physiology, Little Flower Institute of Medical sciences and Research. 30 female post graduate students with mean age 22.3 ± 2 years were included in the study. Standard questionnaire described in literature was used to assess students preference about teaching aids and teaching methods. We conclude that most of the students preferred combination of black board and PPT and teaching followed by tutorials (small group discussion by the teacher). We recommend further detailed study with higher sample size and in multi centers to modulate teaching aids and methods according to the preference of the students for their better academic performance

Effects of fasting during Ramadan month on depression, anxiety and stress and cognition

Objective: The present study was aimed to observe the effect of fasting during the Ramadan month on depression, anxiety and stress scores. Materials and Methods: Twenty healthy male Muslim students of Little Flower Institute of Medical sciences and Research, with previous fasting experience during Ramadan were selected for the present study by convenience sampling method. Depression, anxiety and stress scale (DASS 42) was used to assess depression, anxiety and stress. MMSE (Mini Mental State Examination) was used to assess cognition. Results: Depression, anxiety scores significantly decreased on 14th and 28th day when compared with baseline values. Stress scores were decreased significantly on 28th day. Cognition levels were significantly improved followed by fasting in 14th day and 28th day. Conclusion: In the present study, we have observed positive impact of fasting on depression, anxiety and stress scores and cognitive functions. We recommend further detailed studies including male and female participants and biochemical parameters to investigate other aspects of Ramadan fasting on human stress and cognition