BANGLADESH JOURNAL OF BIOCHEMISTRY

Bangladesh Journal of  Biochemistry
AN INTERNATIONAL JOURNAL IN BIOCHEMICAL SCIENCE

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EFFECTS OF ETHYLENE ON SOME SUBMERGENCE-TOLERANT AND SUSCEPTIBLE RICE (ORYZA SATIVA L.) VARIETIES OF BANGLADESH.

Muktadir Shahid HOSSAIN1, M. Aftab UDDIN1, A.Rashid GOMOSTA2
and M. Anwar HOSSAIN1*

1Department of Biochemistry, University of Dhaka, Dhaka -1000, Bangladesh.
2Department of Plant Physiology, Bangladesh Rice Research Institute (BRRI), Gazipur-1701, Bangladesh.
Author for correspondence :
(FAX : 880-2-865583, E-mail : anwarh@udhaka.net)


Abstract

Ethylene, a gaseous phytohormone, accumulates in submerged rice plants causing rapid elongation which results in lodging once the flood-water recedes. Complete submergence of rice plants under water for 10 days in presence of an ethylene-biosynthetic inhibitor, aminooxy acetic acid (AOA), resulted in appreciable lowering of lodging during post-submergence period when compared with plants submerged without AOA. It was found that, in general, both ethylene production and height elongation were higher in submergence-susceptible varieties than in tolerant ones. Tolerant varieties also formed less ethylene when chilled at 4 C than susceptible ones. Treatments of excised leaves with exogenous ethylene caused destruction of chlorophyll and this effect was more pronounced in susceptible varieties than in tolerant ones. Germinating seeds of a susceptible variety BR5 responded to exogenous ethylene by showing increased elongation of first leaf with increasing concentration of ethylene whereas a tolerant variety FR13A showed almost no response. All these findings suggest that susceptible varieties not only produce more ethylene under stress conditions but also respond more pronouncedly to the phytohormone than tolerant varieties.

Key words : 1-Aminocyclopropane-1-carboxylic acid (ACC)
- Aminooxy acetic acid (AOA) - chilling-chlorophyll-ethylene- gibberellic acid (GA) - germination-lodging - submergence.

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PARTIAL PURIFICATION AND CHARACTERIZATION OF AN IMMUNOREACTIVE FORM OF DIHYDROFOLATE REDUCTASE FROM HUMAN LEUKEMIA CELLS

M. Perwaiz IQBAL*, Naseema MEHBOOBALI and Fakhara SULTANA

Department of Biochemistry, The Aga Khan University, Karachi-74800, Pakistan

* Corresponding author

M. Perwaiz Iqbal, Department of Biochemistry, The Aga Khan University, P. O. Box 3500,
Stadium Road, Karachi-74800, Pakistan. Tel. 92-21-493-0051 Ext. 4463, Fax 92-21-493-4294
E-mail: perwaiz.iqbal@aku.edu


Running title: Immunoreactive forms of dihydrofolate reductase

Abstract

Immunoreactive forms of dihydrofolate reductase, which do not appear to have the enzymatic activity nor the ability to bind methotrexate have been partially purified using affinity chromatography from leukocytes of a cancer-patient suffering from acute myelogenous leukemia. These appear to be heterogeneous proteins with apparent molecular weights 543278, 44000 and 19023 as determined by gel-filtration chromatography. Heterogeneity of the proteins were further confirmed by western immunoblotting. Upon isoelectric focusing, these separated into four immunoreactive proteins with isoelectric points 8.1, 6.6, 6.0 and 5.7. These proteins may be precursors of the active dihydrofolate reductase.

Key words: Dihydrofolate reductase, immunoreactive forms, human leukemia cells, purification, characterization, multiple molecular forms.

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PURIFICATION AND CHARACTERIZATION OF ENDOGLUCANASE (1, 4-BETA-D-GLUCAN, GLUCANHYDROLASE) FROM MICROCEROTERMES SP.

Nilufer Jesmin KHAN, M. Aftab UDDIN and Sharif AKHTERUZZAMAN

Department of Biochemistry, University of Dhaka, Dhaka-1000, Bangladesh.

Corresponding author : Dr.  Sharif Akhteruzzman

Associate  Professor, Department of Biochemistry, University of Dhaka

Tel: 9661900-59/6113
Email: sharif_az@hotmail.com

Abstract

An endoglucanase (1,4-beta-D-glucan, glucanhydrolase) was purified from crude extract of Microcerotermes sp. The enzyme was purified gel filtration on Sephadex G-100 followed by DEAE-anion exchange chromatography. The 22-fold purified enzyme had a specific activity of 0.70 U/mg protein with CM-cellulose as substrate. The optimum pH and temperature of the enzyme were pH 6.0 and 40oC respectively. The enzyme was strongly inhibited by Hg2+, Fe3+ and Cu2+ and moderately by Mn2+, Co2+, Ca2+ and Zn2+. The Km and Vmax values for CM-cellulose were 1.5 mg/mL and 111 nmol/min/mg. Non-SDS PAGE of both the gel filtration and ion exchange chromatography fractions showed that the activity corresponded to a band of around 40 kDa, and this was further confirmed by staining the 40 KDa band for enzyme activity on PAGE as well as after electroelution.

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Key words: Cellulase, termite, crude extract, chromatography

IMPAIRED NEUTROPHIL FUNCTION IN DIABETES MELLITUS

Laila N. Islam*, K. Saiful Islam, M. Enamul Kabir, M. Sazzad Hossain, A.H.M. Nurun Nabi and N.G. Banik**

Department of Biochemistry, University of Dhaka, Dhaka-1000, Bangladesh.

Running title : Neutrophils functions in diabetes mellitus

Key words : diabetes, neutrophil phagocytosis, FMLP polarization, E. coli killing, NBT reduction

*Author for correspondence :

Prof. Laila N. Islam, Department of Biochemistry , University of Dhaka, Dhaka-1000, Bangladesh
Fax : 880-2-8615583, E-mail : laila@udhaka.net

** Department of Biochemistry and Metabolism, BIRDEM Hospital, Shahbag, Dhaka-1000, Bangladesh.


Abstract

The functions of peripheral blood neutrophils were studied in patients suffering from Type I diabetes. The locomotor response towards towards N-formyl-methionyl-leucyl-phenylalanine (FMLP) was studied using a polarization assay. A significantly high proportion of neutrophils from the patients were found to be in the polarized form at the baseline level (p<0.001), and their dose response to FMLP was lower than for healthy control subjects. In quantitative nitroblue tetrazolium (NBT) dye reduction tests also, neutrophils from diabetic patients were found to be more activated at the baseline level (p<0.05), and, on activation, their ability to reduce the dye was less stimulated than for those from healthy controls. These observations suggest that neutrophils are already activated at the resting state in diabetics. The proportion of neutrophils from the patients phagocytic to Saccharomyces cerevisiae was observed to be similar to that of the controls, but the number of activated yeast cells attached was lower. Impairment in phagocytic function in diabetics was observed in that killing of E. coli by neutrophils from the patients was significantly reduced (p<0.05) as compared to those from healthy control subjects. Neutrophil bactericidal activity in patients with moderate or acute diabetes was also significantly suppressed than those with mild diabetes. These findings indicate that there is considerable impairment of neutrophil function in diabetic patients, and that this may contribute to the severe and protracted infection often seen in these patients.

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THIAMINE CONTENT IN BRRI RICE VARIETIES

Fatema BEGUM *, K. A. Kabir, Majeda Begum

Grain Quality and Nutrition Division, Bangladesh Rice Research Institute, Gazipur 1701, Bangladesh

Institute of Food Science and Technology, BCSIR, Dhaka 1205, Bangladesh

(Received for publication, 29 August 2000; and in revised form, 30 November 2000)
Author to whom all correspondence should be addressed.

Abstract

Rice is a good source of thiamine (vitamin B1). Its content in fourteen modern rice varieties developed at BRRI was determined by a modified thiocrome method. The loss of this vitamin during milling and cooking was also estimated. Thiamine content in fourteen non-parboiled brown rice varied from 0.288 mg/100g to 0.413 mg/100 g, and in parboiled brown rice from 0.248 mg/100g to 0.367 mg/100 g. Thus, during parboiling 11.0% to 19.0% thiamine was lost. Loss of thiamine during milling varied from 67% to 75% for non-parboiled and 11% to 26% for parboiled rice. The loss during milling increased with the increase of degree of milling. The degree of milling (bran removal from brown rice) was more for non-parboiled rice than for parboiled rice at equal time of polishing. At similar degree of milling, non-parboiled rice lost more thiamine. The lost thiamine went with the bran. Thiamine was also lost during cooking, Non-parboiled and parboiled milled rice lost 85% to 97% and 73% to 92% respectively when cooked in excess water and the excess water (gruel) drained out. The loss of thiamine declined to 30% -49% and 30%-38% respectively for non-parboiled and parboiled rice when cooked in optimum water with all the water allowed to soak into the cooked rice and no gruel being drained out.

Key Words: Thiamine, BRRI rice

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COMPARATIVE STUDY OF MOSQUITO LARVICIDAL ACTIVITY OF LOCALLY ISOLATED BACILLUS SPHAERICUS STRAINS AND COMMERCIALLY AVAILABLE ONES

A. K. M Mahbub Hasan, M. Jahangir, K. A. Rahim, M. Rahman*

Department of Biochemistry, University of Dhaka, Dhaka-1000, Bangladesh

(Received for publication, 30 October 2000; and in revised form 05 May 2001)
*Author to whom all correspondence should be addressed, E-Mail: mrahman@udhaka.net


Abstract

Mosquito larvicidal activity of locally isolated bacteria, Bacillus sphaericus strain SI-1 (Bs S!-1), has been determined and compared with those of commercially available bacterial strains, Bacillus thuringiensis israelensis (Bti), Bacillus sphaericus strain 1593 (Bs 1593) and Bacillus sphaericus strain 2362 (Bs 2362). The spores from Bs SI-1 were more potent as mosquito larvicidal gent than those from Bs 1593 and Bs 2362 while those from Bti were the most potent. When the mosquito larvicidal activities of crude protein extracts of these organism were compared, it was found to decrease in the following order: Bti>Bs 1593>BsSI-1>Bs 2362

Key Words: 3rd instar mosquito larvae/ B. Thuringiensis israelensis/ B. shaericus

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Copyrightę 2003 By The Bangladesh Biochemical Society, Bangladesh.