Biomedical subjects

Somnath Bhattacharyya

Publications and source records attributed to Somnath Bhattacharyya.

5 recordsLinked to original sources

PubMed2006

Projected potential profiles across interfaces obtained by reconstructing the exit face wave function from through focal series.

An iterative method for reconstructing the exit face wave function from a through focal series of transmission electron microscopy image line profiles across an interface is presented. Apart from high-resolution images recorded with small changes in defocus, this method works also well for a large defocus range as used for Fresnel imaging. Using the phase-object approximation the projected electrostatic as well as the absorptive potential profiles across an interface are determined from this exit face wave function. A new experimental image alignment procedure was developed in order to align images with large relative defocus shift. The performance of this procedure is shown to be superior to other image alignment procedures existing in the literature. The reconstruction method is applied to both simulated and experimental images.

Journal Article↗

PubMed2004

Ego functions in relation to stressful life events and indices of psychopathology in paranoid schizophrenia.

This study explored the role of 12 ego functions in relation to Stressful Life Events and three indices of psychopathology, namely, Psychoticism, Anxiety, and Depression among 60 Bengali adult patients suffering from Paranoid Schizophrenia. Adapted versions of Bellak's Ego Function Assessment-M, Eysenck's Personality Questionnaire, Beck Depression Inventory, and the State-Trait Anxiety Inventory were administered to them. Stepwise multiple regression analyses indicated that Object Relation was associated with all three indices. Scores on Reality Testing correlated with those on Psychoticism, Stressful Life Events and scores on Thought Process with Anxiety, and Stressful Life Events, Sense of Reality, and scores on Defensive Functions with Depression. Hierarchical multiple regression analyses indicated that Object Relation also moderated between stressful life events and anxiety.

Adult↗

PubMed2003

Intron-mediated enhancement of gene expression in transgenic plants using chimeric constructs composed of the Peanut chlorotic streak virus (PClSV) promoter-leader and the antisense orientation of PClSV ORF VII (p7R).

The antisense orientation of the Peanut chlorotic streak virus (PClSV) open reading frame (ORF) VII (denoted as p7R), in conjunction with the sense orientation of the PClSV leader sequence, acts as an intron and enhances the expression of a reporter gene, analyzed in protoplasts and transgenic plants of tobacco ( Nicotiana tabacum L.). Correct 5' and 3' splicing sites were determined for intron removal from the chimeric constructs using either beta-glucuronidase (GUS) or chloramphenicol acetyltransferase (CAT) as a reporter gene. In this splicing process, the active consensus 5' splicing donor site (AG/GTATA) is located at position +283 to +289 from the transcription start site (TSS) of the PClSV full-length transcript (FLt). The 3' splice site (TAG/GATT) is located on the p7R sequence at position +785 to +791 from the TSS. The combination of PClSV FLt leader and p7R enhanced the expression of reporter genes (CAT and GUS) by as much as 2-fold compared to the strong constitutive PClSV FLt promoter without an interfering leader sequence and about 30- to 800-fold compared to constructs containing the sense orientation of PClSV ORF VII (p7) in both protoplast transient-expression experiments and stably transformed transgenic plants. An increased level of mature transcripts accompanied this. This suggests that this combination of elements can mediate the intron-mediated enhancement (IME) phenomenon. We also demonstrated comparative IME with other heterologous promoters from caulimoviruses.

Base Sequence↗

PubMed2003

A novel mitogenic protein that is highly expressed in cells of the gastric antrum mucosa.

Human and pig cDNAs for a novel stomach protein, the product of a gene expressed at high levels specifically in cells of the antrum mucosa, have been characterized. The general exon/intron structure of the genomic DNA is conserved in humans and mice. The predicted protein sequences of the human and mouse mRNAs contain 185 and 184 amino acids, respectively. The protein isolated from pig antral extracts has an NH2 terminus consistent with cleavage of a 20-amino acid signal peptide. Human cDNA was expressed in E. coli to generate a protein antigen for antibody production. The antibodies detected polypeptides of approximately 18 kDa in antrum extracts from all mammalian species tested. Immunocytochemistry located antrum mucosal protein (AMP)-18 to surface mucosal cells of the mouse antrum and, specifically, to secretion granules, suggesting that it is cosecreted with mucins. Antrum extracts and recombinant human AMP-18 exhibit growth-promoting activity on epithelial cells that can be blocked by the specific antisera. We suggest that AMP-18 is a "gastrokine" that maintains the integrity of the gastric mucosal epithelium.

Amino Acid Sequence↗

PubMed2002

Analysis of cis-sequence of subgenomic transcript promoter from the Figwort mosaic virus and comparison of promoter activity with the cauliflower mosaic virus promoters in monocot and dicot cells.

A sub-genomic transcript (Sgt) promoter was isolated from the Figwort mosaic virus (FMV) genomic clone. The FMV Sgt promoter was linked to heterologous coding sequences to form a chimeric gene construct. The 5'-3'-boundaries required for maximal activity and involvement of cis-sequences for optimal expression in plants were defined by 5'-, 3'-end deletion and internal deletion analysis of FMV Sgt promoter fragments coupled with a beta-glucuronidase reporter gene in both transient protoplast expression experiments and in transgenic plants. A 301 bp FMV Sgt promoter fragment (sequence -270 to +31 from the transcription start site; TSS) provided maximum promoter activity. The TSS of the FMV Sgt promoter was determined by primer extension analysis using total RNA from transgenic plants developed for FMV Sgt promoter: uidA fusion gene. An activator domain located upstream of the TATA box at -70 to -100 from TSS is absolutely required for promoter activity and its function is critically position-dependent with respect to TATA box. Two sequence motifs AGATTTTAAT (coordinates -100 to -91) and GTAAGCGC (coordinates -80 to -73) were found to be essential for promoter activity. The FMV Sgt promoter is less active in monocot cells; FMV Sgt promoter expression level was about 27.5-fold higher in tobacco cells compared to that in maize cells. Comparative expression analysis of FMV Sgt promoter with cauliflower mosaic virus (CaMV) 35S promoter showed that the FMV Sgt promoter is about 2-fold stronger than the CaMV 35S promoter. The FMV Sgt promoter is a constitutive promoter; expression level in seedlings was in the order: root>leaf>stem.

Base Sequence↗