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Indian Journal of Biochemistry & Biophysics

 

 

 

 

ISSN : 0301-1208

CODEN : IJBBBQ  

VOLUME 41

NUMBER 5

OCTOBER 2004

  

 

CONTENTS

 

Minireview

Genetic transformation in Aspergilli: Tools of the trade

205

V Lakshmi Prabha and N S Punekar*

 

 

 

Papers

 

Purification, characterization and antigenic species-specific reactivity of vitellogenin of rosy barb (Puntius conchonius Hamilton)


216

Xiaodong Shi, Shicui Zhang*, Yaning Sun, Qiuxiang Pang and M S Sawant

 

 

 

Developmental changes in intestinal brush border enzymes of rats prenatally exposed to ethanol

221

Sonali Bhalla, Kamaljit Kaur, Safrun Mahmood* and Akhtar Mahmood

 

 

 

O-Phthalic acid, a dead-end product in one of the two pathways of phenanthrene degradation in Pseudomonas sp. strain PP2


227

Samyuktha Krishnan, Yogikala Prabhu and Prashant S Phale*

 

 

 

Characterization of non-planar peptide groups in protein crystal structures

233

Anjan Kumar Dasgupta, Rabi Majumdar and Dhananjay Bhattacharyya*

 

 

 

Numerical solution of unsteady blood flow through an indented tube with atherosclerosis

241

K Venkateswarlu* and J Anand Rao

 

 

 

Notes

 

Polyunsaturated fatty acids inhibit mouse hepatic glucocorticoid receptor activation in vitro

246

H S Ranhotra* and R Sharma

 

 

 

Iron dependence and zinc inhibition of duodenal cytosolic aconitase of rat

250

Bodiga Sreedhar and K Madhavan Nair*

 

 

 

Kinetic studies on thermal denaturation of C-phycocyanin

254

Anamika Patel, Richa Pawar, Sandhya Mishra*, Shailendra Sonawane and P K Ghosh

 

 

 

Comparative modelling of tetramanganese cluster of Chaetosphaeridium globosum

258

L S Rath and M K Raval*

 

 

 

Instructions to Authors

263

   
Author Index
 

*Author for correspondence

 

MINIREVIEW

 

Indian Journal of Biochemistry & Biophysics

 Vol. 41, October 2004, pp. 205-215

 

Genetic transformation in Aspergilli: Tools of the trade

V Lakshmi Prabha and N S Punekar*

 

DNA-mediated transformation is a powerful tool that allows the introduction of specific genetic changes in an organism. Transformation of Aspergilli, acclaimed for their wide use in the industry, has been possible for about two decades now. Several basic and applied problems related to fungal biology have been addressed using this technique. Nonetheless, new markers and strategies for transformation are still being developed for these filamentous fungi. Different methods and markers that are currently available for the transformation of Aspergilli are summarized here. The review also brings out the importance of these transformation systems in analyzing fungal gene function. Aspects of Aspergillus niger transformation are selectively emphasized.

 

Keywords: Aspergilli, Aspergillus niger, transformation strategies, genetic markers, transformation vectors, gene function

 

 

 

Indian Journal of Biochemistry & Biophysics

 Vol. 41, October 2004, pp. 216-220

 

Purification, characterization and antigenic species-specific reactivity of vitellogenin of
rosy barb (Puntius conchonius Hamilton)

Xiaodong Shi, Shicui Zhang*, Yaning Sun, Qiuxiang Pang and M S Sawant

  

Vitellogenin (Vg) was isolated using gel filtration and ion-exchange chromatography from plasma of rosy barb (Puntius conchonius) treated with estrogen (estradiol-17β). The purified Vg was stained positive for carbohydrate, lipid and phosphorus and was rich in Ala (10.58%), Asp (8.46%), Glu (10.30%), Leu (11.23%), Lys (7.22%) and Val (7.49%). It appeared as a single band of approximately 450 kDa in native PAGE and was reduced to a single band of approximately 167 kDa under SDS-PAGE, suggesting that it is probably composed of three identical polypeptide subunits. Double-immunodiffusion assay showed that the plasma from female rosy barb reacted with the mouse antisera against rosy barb Vg, forming a single immunoprecipitin line, while the plasma from male rosy barb or female zebrafish showed no such reactivity, confirming the existence of the sex- and species-specific reactivity for rosy barb Vg antisera.

 

Keywords: Rosy barb, vitellogenin (Vg), characterization, immunodiffusion, phospholipoglycoprotein, Puntius conchonius, purification.

 

 

 

Indian Journal of Biochemistry & Biophysics

 Vol. 41, October 2004, pp. 221-226

 

Developmental changes in intestinal brush border enzymes of rats prenatally exposed to ethanol

Sonali Bhalla, Kamaljit Kaur, Safrun Mahmood* and Akhtar Mahmood

  

The activities of lactase, sucrase, alkaline phosphatase (AP) and g-glutamyl transpeptidase (g-GTP) were studied in the intestinal brush border membranes of pups born to rat mothers exposed to ethanol (1 ml of 30% ethanol daily during gestation) at different days of postnatal development. The activities of lactase (at day 4-20) and sucrase (at day 20-30) were considerably reduced in response to prenatal exposure to ethanol, while AP (at day 4-30) and g-GTP activities were significantly enhanced (p<0.05) at day 4, 8, 14 and 20, but there was no significant difference by day 30 of postnatal development. The observed changes in enzyme activities were corroborated by Western blot analysis of lactase, sucrase and AP. Kinetic studies revealed a change in Vmax without affecting apparent Km of enzymes under these conditions. The present findings suggest that in utero ethanol exposure to rats is embryotoxic and affects the postnatal development of various brush border enzymes, which persist long after the ethanol was withdrawn prior to birth.

 

Keywords: Prenatal ethanol exposure, intestinal brush border enzymes, postnatal development

 

 

 

Indian Journal of Biochemistry & Biophysics

 Vol. 41, October 2004, pp. 227-232

 

o-Phthalic acid, a dead-end product in one of the two pathways of phenanthrene degradation
in Pseudomonas sp. strain PP2

Samyuktha Krishnan, Yogikala Prabhu and Prashant S Phale*

  

Phenanthrene is degraded via either o-phthalic acid or 1, 2-dihydroxynaphthalene in bacteria. A soil isolate Pseudomonas sp. strain PP2 degrades phenanthrene as the sole source of carbon, but failed to utilize naphthalene [Prabhu and Phale (2003) Appl Microbiol Biotechnol 61:342-351]. Analysis of the phenanthrene-grown culture spent media of this strain by gas chromatography-mass spectrometry (GC-MS) showed accumulation of o-phthalic acid. The cell-free extract prepared from this strain showed activity of 1-hydroxy-2-naphthoic acid dioxygenase (1-H-2-NADO). The extract showed conversion of 1-hydroxy-2-naphthoic acid and 2-carboxybenzaldehyde to o-phthalic acid, as analyzed by thin layer chromatography and GC-MS. However, it failed to grow or respire on o-phthalic acid. These results suggest that besides 1, 2-dihydroxynaphthalene pathway, the strain has a truncated o-phthalic acid pathway for phenanthrene metabolism and excretes o-phthalic acid as a dead-end product, indicating the co-existence of two pathways. 1-H-2-NADO, the key enzyme of o-phthalic acid pathway is inducible, has pH optima of 7.5, does not require external addition of Fe(II) as a co-factor and is completely inhibited by 1,10-phenanthroline. Absence of product formation under anaerobic condition and stoichiometric consumption of 0.82 moles of O2 per mole of product formed confirmed the dioxygenase nature of the enzyme.

 

Keywords: Pseudomonas sp. strain PP2, phenanthrene metabolism, 1, 2-dihydroxynaphthalene, o-phthalic acid, 1-hydroxy-2-naphthoic acid dioxygenase

 

 

 

Indian Journal of Biochemistry & Biophysic

 Vol. 41, October 2004, pp. 233-240

 

Characterization of non-planar peptide groups in protein crystal structures

Anjan Kumar Dasgupta, Rabi Majumdar and Dhananjay Bhattacharyya

 

Peptide groups are generally assumed to be planar in protein structure, due to ‘rigid’ partial double bond character of peptide bonds, thus the value of peptide torsion angle w should be restricted to 180o for the usual trans form of peptide unit. However, on analyzing the ultra-high resolution protein crystal database, we find that in some cases, w deviates >10° from its usual value of 180°, indicating significant non-planarity of peptide groups. Moreover, the non-planarity for most of the amino acids is found to be ‘biased’ towards values of w smaller than 180°. Similar trend for w is confirmed by the neutron diffraction data for proteins. The neutron diffraction database also reveals that non-planar peptide groups are generally correlated to ‘pyramidal’ structure of the peptide-nitrogen bonds. Consequently, the hydrogen atom of peptide group deviates from its planar position, as measured by the ‘improper’ torsion angle q. Thus, we find that both the angles w and q point towards a significant amount of non-planarity of peptide groups, which cannot be ignored. The role of peptide non-planarity in protein function is, however, not yet clear.

 

Keywords: X-ray diffraction, database analysis, neutron diffraction, non-planar peptide, peptide bond, protein crystal structure.

 

 

 

Indian Journal of Biochemistry & Biophysics

 Vol. 41, October 2004, pp. 241-245

 

Numerical solution of unsteady blood flow through an indented tube with atherosclerosis

K Venkateswarlu* and J Anand Rao

  

The unsteady blood flow through an indented tube with atherosclerosis in the presence of mild stenosis has been studied numerically by finite difference method. The effects of hematocrit, frequency parameter, height of stenosis, parameter determining the shape of the constriction on velocity field, volumetric flow rate, pressure gradient of the fluid in stenotic region and wall shear stress at the surface of stenosis are obtained and shown graphically.

 

Keywords: Unsteady blood flow, indented tube, atherosclerosis, stenosis, and finite difference method

 

 

 

Indian Journal of Biochemistry & Biophysics

Vol. 41, October 2004, pp. 246-249

 

Polyunsaturated fatty acids inhibit mouse hepatic glucocorticoid receptor activation in vitro

H S Ranhotra* and R Sharma

 

The effect of saturated fatty acids (SFAs) stearic and palmitic acids and polyunsaturated fatty acids (PUFAs) oleic, linoleic and arachidonic acids was studied on in vitro heat activation of mouse hepatic glucocorticoid receptor (GR) complex, as assessed by binding to DNA-cellulose and purified nuclei. Significant dose-dependent inhibition of heat activation of hormone-receptor complex by the PUFAs was observed. Linoleic and arachidonic acids were found to be more potent (caused ~70% inhibition maximally at 160 mM) inhibitors of GR heat activation, compared to oleic acid (~38% inhibition at 40 mM). However, stearic and palmitic acids were unable to modulate GR heat activation, suggesting that the unsaturated moieties in PUFAs are possibly the important determinants of receptor activation. Thus, our study shows an inhibitory effect of PUFAs on in vitro hepatic GR activation.

 

Keywords: Fatty acids, mice, liver, activation, glucocorticoid receptor

 

 

 

Indian Journal of Biochemistry & Biophysics

Vol. 41, October 2004, pp. 250-253

 

Iron dependence and zinc inhibition of duodenal cytosolic aconitase of rat

Bodiga Sreedhar and K Madhavan Nair*

  

The response of duodenal cytosolic aconitase (c-aconitase) to oral repletion of graded doses of iron (Fe) during Fe-deficiency was studied in rats (WNIN strain). In addition, in vitro effect of zinc (Zn) on the enzyme activity was studied using duodenal cytosol. Iron-depleted male rats were orally repleted with either 100 or 190 or 370 mg of Fe/day (n=6, each) for 2 weeks. Fe repletion was found to increase linearly the activity of duodenal c-aconitase along with the indicators of iron status. The correlation coefficient (r) between c-aconitase and haemoglobin and mucosal ferritin was 0.6453 and 0.8441, respectively. The effects of zinc (0-40 mM) in vitro on the kinetics of c-aconitase from iron-replete stock diet fed rats (n=4) showed that Zn competitively inhibited the enzyme with a Ki (app.) of 28 mM. These observations suggest that c-aconitase is a critical target involved in the assimilation of Fe and excess dietary Zn can result in negative interactions.

 

Keywords: Fe deficiency, cytosolic aconitase, duodenum, zinc, rat

 

 

 

Indian Journal of Biochemistry & Biophysics

 Vol. 41, October 2004, pp. 254-257

 

Kinetic studies on thermal denaturation of C-phycocyanin

Anamika Patel, Richa Pawar, Sandhya Mishra*, Shailendra Sonawane and

P K Ghosh

  

The kinetics of thermal denaturation of a biliprotein, C-phycocyanin (C-PC) isolated from Spirulina platensis were studied at different pH values, ranging from 4.0 to 8.0. The denaturation of C-PC follows the first order kinetics and rate constant at pH 5.0 and temperature 55ºC is found to be 4.37 ´ 10-5 s-1, which increases to 5.46 ´ 10-5 s-1 at pH 7.0. The denaturation rate is much higher at 65ºC and pH 7.0 (7.96 ´ 10-4), as compared to at pH 5.0 (1.46 ´ 10-4). The thermal stability of C-PC is more at pH 5.0, as compared to other pH values. The observed differences in entropy values at pH 5.0, as compared to other pH values indicate a considerably close fit structure of the protein at pH 5.0, which increases the stability of native structure, even at higher temperature (65ºC).

 

Keywords: Phycobiliproteins, Spirulina platensis, C-Phycocyanin, thermal denaturation, first order kinetics

 

 

 

Indian Journal of Biochemistry & Biophysics

 Vol. 41, October 2004, pp. 258-262

 

Comparative modelling of tetramanganese cluster of Chaetosphaeridium globosum

L S Rath and M K Raval*

 

The D1 protein of photosystem II (PS II) complex of a microalga Chaetosphaeridium globosum has been theoretically modelled from its sequence using comparative modeling with known backbone structure of D1 protein from bacterium Thermosynechococcus vulcanus as template. The model is built with missing loops and all side chains, which are not resolved in the structure of the template. The structure of the tetramanganese cluster (TMC) and the ligand forming side chains have been subjected to modeling studies in order to gather more information useful to understanding of the water splitting reactions. Earlier models of TMC have been scrutinized and an insight into the manganese coordination sphere has been provided.

 

Keywords: Photosystem II, D1 protein, water oxidizing complex, tetra manganese complex, comparative modeling, Chaetosphaeridium globosum, Thermosynechococcus vulcanus

 

 

 

Author Index

 

Bhalla S

221

Majumdar R

233

Rath L S 

258

Bhattacharyya D 

233

Mishra S 

254

Raval M K 

258

 

 

 

 

 

 

Dasgupta A K    

233

Nair K M 

250

Sawant M S 

216

 

 

 

 

Sharma R

246

Ghosh P K 

254

Pang Q

216

Shi X

216

 

 

Patel A 

254

Sonawane S 

254

Kaur K

221

Pawar R

254

Sreedhar B 

250

Krishnan S 

227

Phale P S

227

Sun Y

216

 

 

Prabhu Y

227

 

 

Lakshmi V P 

205

Punekar N S

205

Venkateswarlu K 

241

 

 

 

 

 

 

Mahmood A 

221

Ranhotra H S

246

Zhang S 

216

Mahmood S  

221

Rao J A

241