BANGLADESH JOURNAL OF BIOCHEMISTRY

Bangladesh Journal of  Biochemistry
AN INTERNATIONAL JOURNAL IN BIOCHEMICAL SCIENCE

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PRODUCTION OF CELLULOSE-DEGRADING ENZYMES FROM A NEWLY ISOLATED THERMOPHILIC FUNGUS THERMOASCUS AURANTIACUS
IN SHAKE-FLASK AND IN BIOREACTOR CULTURES

Donald James GOMES,1* and Walter STEINER2

1Department of Microbiology, University of Dhaka, Dhaka-1000, Bangladesh and
2Institute of Biotechnology, Technical University Graz, Petersgasse 12, A-8010, Graz, Austria

_______________________________________________________________________
*To whom correspondence should be addressed


Abstract

The production of cellulases was investigated with a newly isolated strain of thermophilic fungus, Thermoascus aurantiacus. The medium composition was optimized on a shake-flask scale using the Graeco-Latin square technique. The traditional one-factor-at-a-time method was employed for selecting the effective factors and the initial test range of each ingredient. The optimized medium composition was found to be 3.5% steam-treated ground wheat straw, 1.0% pharmamedia (cotton seed-derived protein), 0.5% KH2PO4 and 0.1% Tween 80. The enzyme production in shake-flask cultures using the optimized culture medium with an initial pH range of 4.0-5.5 were maximum when incubated at 45-50 C under shaking at 150 rpm. The optimized culture medium and culture conditions gave 3.6 nkat of filter paper cellulase (FPCase), 155.8 nkat of carboxymethyl cellulase (CMCase) and 40.8 nkat of -glucosidase per ml of culture filtrate at 240 h of shake culture. In bioreactor cultures using the optimized culture medium, the fungus produced maximum levels of the enzymes when pH was not controlled and starch-glucose-grown preculture was used as inoculum. Batch cultivation under these conditions allowed the production of 3.7 nkat of FPCase, 119.7 nkat of CMCase and 48.3 nkat of -glucosidase per ml of culture filtrate in 158 h.

Key words: Cellulase, Optimization, Thermoascus aurantiacus, Wheat straw


PURIFICATION, SUBUNIT STRUCTURE AND SOME CHARACTERISTICS OF THREE SILKWORM PUPAE PROTEINS FROM BOMBYX MORI L

Md. Razaul Karim, M. Habibur Rahman  , Parvez Hassan 1 , Nurul Absar*.

*Department of Biochemistry, Rajshahi University, Rajshahi -6205, Bangladesh

(Received for publication, 25 November 1998; and in revised form, 31 August 2000)

Key Words: Silkworm, (Bombyx mori L.), Pupae protein, Relative molecular mass, Subunit structure, Pup=Pupae protein


Abstract

Three major proteins, designated as Pup-1, Pup-4 and Pup-6 were purified from crude protein extract of silkworm (Bombyx mori L.) pupae by gel filtration on Sephadex G-75 followed by ion exchange chromatography on DEAE-cellulose to a homogenous state as confirmed by polyacrylamide disc gel electrophoresis (PAGE). SDS-polyacrylamide gel electrophoresis of Pup-1 protein fraction showed a single band with molecular weight of 190 kDa in presence or absence of -mercaptoethanol indicating that the Pup-1 protein is a single polypeptide chain. The protein Pup-4 gave 4 bands with relative molecular masses of about 80 kDa , 48 kDa, 31 kDa and 14 kDa in absence of -mercaptoethanol on SDS-PAGE, suggesting that the tertameric subunits of Pup-4 protein are held together by non-ionic hydrophobic interactions. On the other hand, the protein Pup-6 gave a single band (145 kDa) in absence of -mercaptoethanol on SDS-PAGE while in the presence of -mercaptoethanol, Pup-6 protein dissociated into 4 subunits with relative molecular masses of 53 kDa, 43 kDa, 33 kDa and 15 kDa. This suggested that the 4 subunits of Pup-6 protein are held together by disulfide bonds. Further, the relative molecular masses of the purified native proteins were estimated to be 185 kDa, 170 kDa and 140 kDa for Pup-1, Pup-4 and Pup-6, respectively by the gel filtration method and are in good agreement with that obtained by polyacrylamide gel electrophoresis. Pup-1, Pup-4 and Pup-6 proteins were judged to be glycoproteins having sugar content of 4.05%, 3.15% and 0.605% respectively. The major amino acid compositions of pupae proteins were determined.

Corresponding author: M. Habibur Rahman Department of Biochemistry, Rajshahi
University, Rajshahi -6205, Bangladesh
1 Present address: Institute of Biological Sciences, Rajshahi University, Rajshahi- 6205.


ANTINEOPLASTIC ACTIVITY OF CHLOROACETOHYDROXAMIC ACID IN COMBINATION WITH ULTRASOUND

J.A. Khanam, Department of Biochemistry, Rajshahi University, Rajshahi-6205, Bangladesh


Abstract

Antitumour activity of chloroacetohydroxamic acid (CHA), ultrasound and CHA in combination with ultrasound has been studied against Ehrlich ascites carcinoma (EAC) cells in Swiss A mice. It has been found that individual treatment of both CHA and ultrasound has enhanced the longivity of tumour bearing mice. The logivity has increased remarkably with the combination treatment. Further in comparison with individual treatments (CHA and ultrasound) this combination treatment has restored the altered haematological parameters and alkaline phosphatase (ALKP) activity more closely towards normal.

IN VITRO STUDY OF THE EFFECT OF INDAN-1-ACIDS ON THE OXIDATION OF INDOLE-3-ACETIC ACID BY HORSERADISH PEROXIDASE ENZYME

Sitesh Chandra Bachar* and Samir Chandra Lahiri

Department of Pharmaceutical Technology, Medicinal Chemistry Division,
Jadavpur University, Calcutta 700032, India

(Received for publication, 22 December 1999; and in revised form, 15 November 2000)

Key words: Indan-1-carboxylic acid, Indan-1-acetic acid, Indole-3-acetic acid, Horseradish peroxidase.

Abstract

The effect of two synthetic auxins, indan-1-carboxylic acid and indan-1-acetic acid, on the peroxidase-catalyzed oxidation of a natural auxin, indole-3-acetic acid (IAA), was studied at different time intervals. Both the indan-1-acids appeared to inhibit oxidation of IAA by the enzyme horseradish peroxidase. After 30 minutes of in vitro exposure to the peroxidase, IAA was completely oxidised while in the presence of indan-1-carboxylic acid and indan-1-acetic acid, the oxidation of IAA decreased to 84.45% and 89.40% respectively. Of the two acids tested, indan-1-carboxylic acid showed a comparatively higher efficacy in controlling oxidative degradation of IAA than indan-1-acetic acid.

* Author to whom all correspondence should be addressed: Sitesh C. Bachar, Department of Pharmacy, University of Dhaka, Dhaka 1000, Bangladesh. E-mail : scbachar@yahoo.com

ANTITUMOR ACTIVITY OF VITIS TRIFOLIA LINN. (FAMILY-VITACEAE)

Joydeb K. KUNDU1*, Abu Shara S. ROUF1, Md. Nazmul HOSSAIN1 and Md Aftab UDDIN2
1Department of Pharmacy, University of Dhaka, Dhaka-1000, Bangladesh
2Department of Biochemistry, University of Dhaka, Dhaka-1000, Bangladesh

(Received 05 March 2000, revised 18 January 2001)

Abstract

Sun-dried whole Vitis trifolia L. plant powder was extracted with n-hexane and the extract evaporated to dryness. The residue was subjected to vacuum liquid chromatography (VLC) using petroleum ether and ethylacetate. Four VLC fractions namely H1, H2, H3 and H4 as well as a partially purified fraction VT-1 (obtained by rechromatography of fraction H4) were studied by potato disc bioassay method for antitumor activity. Significant inhibitions of crown gall tumor formation were observed for fractions H2, H3, H4 and VT-1 while fraction H1 showed no significant inhibition.

Keywords: Vitis trifolia, Agrobacterium tumefaciens, Crown gall tumor, Potato-disc bioassay

*Corresponding author
Department of Pharmacy
University of Dhaka, Dhaka-1000, Bangladesh
Ph: 880-2-9661900-59 Extn. 4835
Fax : 880-2-8615583
Email : kundujk@yahoo.com

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Copyrightę 2003 By The Bangladesh Biochemical Society, Bangladesh.