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Bangladesh Journal of Biochemistry, Vol. 3, No. 2, 45-52, December
1997
MULTIPLE
FORMS OF DIHYDROFOLATE REDUCTASE IN LEUKOCYTES OF CANCER PATIENTS WITH
NON-HEMATOLOGICAL MALIGNANCIES
M. Perwaiz IQBAL, Fakhra SULTANA, Naseema MEHBOOBALI, N.
Ikram A. BURNEY, Tariq SIDDIQUI and M. Anwar WAQAR
Departments of Biochemistry and Medicine, The Aga Khan
Univertity, Stadium Road, Karachi-74800, Pakistan
(Received April 16, 1998)
Abstract
An immunoreactive
form of dihydrofolate reductse, which is different from the active
enzyme, has been identified in large quantity in leukocytes of cancer
patients with different types of non-hematological malignancies by
using enzyme linked immunosorbent assay (ELISA). The size of this
immunoreactive but apparently non-functional enzyme is larger than
the active dihydrofolate reductase.This protein with antegenic homology
to dihydrofolate reductase present in leukocytes of a patient with
Adenocarcinoma and a patient with Hodgkin’s disease could be converted
into small size proteins having no enzyme activity by using
4M urea and 40mM dithioerythritol. However, the protein present
in the leukocytes of patients with non Hodgkin’s lymphoma and small
cell lung carcinoma could not be dissociated into small size proteins
suggesting a heterogeneity in the structure of this protein in different
types of cancer.
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Bangladesh
Journal of Biochemistry, Vol. 3, No. 2, 53-68, December
1997
CHEMICAL
MODIFICATIONS OF LUFFIN-a, A RIBOSOME INACTIVATING PROTEIN FROM LUFFA
CYLINDRICA SEEDS- THE INVOLVEMENT OF HIS-140 AND TYR-165 IN ITS ACTIVITY
M. Rafiqul ISLAM, M.
Ahad ALI and Gunki FUNATSU
Laboratory of Protein Chemistry and Engineering, Faculty of Agriculture, Kyushu
University, Fukuoka 812, Japan
(Received June 16,
1998)
Abstract
Luffin-a present
in the seeds of sponge gourd appeared to be one of the strongest ribosome
inactivating proteins (RIPs). In order to identify the residues in
the active center of this molecule, we modified luffin-a with amino
acid specific reagents. The only tryptophan residue in luffin-a was
inert towards N-bromosuccinimide oxidation. Four arginine residues
were rapidly modified with
excess of phenylglyoxal, but only 60% loss in activity indicated that
arginine residues are not located in the active center of this protein.
Carbodiimide rapidly esterified 11 carboxyl groups in luffin-a with
concurrent complete loss of activity, suggesting that one or more
of these residues might be involved in enzymatic activity. Treatments
with excess N-[(iodoacetyl)
amino-ethyl]-5-naphthylamine-1-sulfonic acid and 1mM diethylpyrocarbonate
modified the single histidine residue (His-140) present in luffin-a
without alteration of other residues. Modification of this His residue
reduced luffin’s protein synthesis inhibitory (PSI) activity to only
8%. Treating luffin-a with excess
N-acetylimidazole acetylated 4 tyrosine residues and decreased
its PSI-activity to 14%. A similar extent
of activity loss was also observed when 1.3 tyrosine residues
per mol in luffin-a was iodinated with excess of KI3.
Isolation and sequencing of the readioiodinated tryptic peptides from [125]luffin-a
revealed Tyr-165 as the major radioactivity containing residue. These
results suggests that His-140 and Tyr –165 are critical for the PSI-activity
of luffin-a.
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Bangladesh
Journal of Biochemistry, Vol. 2, No. 1, 69-74, December
1997
CARDIOACTIVE
AND ANTIPYRETIC ACTIVITY OF SOLANUM XANTHOCARPUM
A.S. Shamsur ROUF,
Biplob K. MITRA,and Joydeb K. KUNDU,
Department of Pharmacy. Department of Biochemistry,
M. Aftab UDDIN
University of Dhaka,
Dhaka-1000, Bangladesh
(Received
February 22, 1998)
Abstract
The
effect of petroleum ether, ethylacetate and methanol extracts of Solanum
xanthocarpum on toad heart muscle was studied. The effect of the
petroleum ether extract on toxin-induced pyrexia in rabbits was also
studied. The petroleum ether and methanol extracts were found to increase
heart rate significantly while ethylacetate extract and standard drug
digoxin caused a significant decrease in the heart rate. A significant
increase in cardiac muscle contractility was observed with ethylacetate
and methanol extracts whereas a significant decrease in contractility
was caused by petroleum ether extract. The petroleum extract caused
a lowering of temperature index in toxin induced pyrexia, indicating
antipyretic activity of the petroleum extract.
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Bangladesh
Journal of Biochemistry, Vol. 3, No. 2, 75-86,
December 1997
MODULATION
OF HUMAN NEUTROPHIL FUNCTIONS BY VIBRIO CHOLERAE LIPOPOLYSACCHARIDE
Laila N. ISLAM,
Kazi Mokim AHMED and Shahnaj SHAMMY
Department of Biochemistry, University of Dhaka, Dhaka-1000, Bangladesh
(Received
May 18, 1998)
Abstract
The locomotor response
of human neutrophils to lipopolysaccharide (LPS, commonly known as
endotoxin) of Vibrio cholerae Inaba 569B was studied using
a polarization assay on cells in suspension and compared to that induced
by N-formyl-methionyl-leucyl-phenylalanine (FMLP).The test LPS induced
morphological polarization in neutrophils and hence was a chemostimulant.
Neutrophils were pretreated with an optimal of LPS and its effects
upon their adhesion, locomotion, nitro blue tetrazolium (NBT) dye
reduction and phagocytic activity were tested. The results showed
that the LPS inhibited neutrophil phagocytosis of opsonized yeast
but not of the unopsonized yeast. The inhibitory effect on phagocytosis
by Vibrio endotoxin challenged neutrophils was retained after
thorough washing of the cells. On the contrary, uniform concentration
of the LPS stimulated the neutrophils to exhibit increased random
locomotion (chemokinesis) through cellulose nitrate filters. Furthermore,
the endotoxin stimulated the neutrophil to reduce NBT dye and increased
neutrophil adhesion to clean glass. These results suggest that LPS
of V. cholerae binds to neutrophils, cause membrane alteration
and hyperadhesion of the cells which interfere with the C3b-and/or
Fc-receptor mediated phagocytic activity of the cells and thus modulate
neutrophil functions.
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Bangladesh
Journal of Biochemistry, Vol. 3, No. 2, 87-93,
December 1997
RELATIONSHIP
OF GLYOXYLASE-1 ACTIVITY WITH REGENERATION POTENTIAL OF EMOBRYO-DERIVED RICE
CALLUS
M. Moksed ALI,
Zahidul ISLAM, Mohammad ALI, Noorain M. RASUL, N. Tasnim FARZANA, M. Omar
FARUQUE, Zeba I. SERAJ and
Ishtiaq MAHMUD
Department of Biochemistry, University of Dhaka, Dhaka-1000, Bangladesh
(Received October 14,
1997)
Abstract
Glyoxalase-1 activity
of 21-day old calli from nine different rice varieties was found to
be inversely proportional to their regeneration potential. The regeneration
potential of rice calli was identified as high, intermediate or low
based on regeneration per cent and number of plantlets regenerated
per embryo. The differences in glyoxalase-1 activity were significant
at the 5% level as judged by Duncan’s Multiple Range Test. Seven and
14-day old calli of four of the above varieties with high and poor
regeneration were also assayed for glyoxalase-1 activity. Enzyme activities
of the highly regenerative and poorly regenerative calli are low at
7 days but increase significantly at 14 days with no statistical difference
between the high and poor groups. However, the enzyme activity for
the calli in the high group decreases at 21 days whereas the activity
of the calli in the poor group remains high.
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Bangladesh Journal of Biochemistry, Vol. 3, No.
2, 95-98, December 1997
IN VITRO REGENERATION OF SIX INDICA RICE CULTIVARS
Mariam NASREEN and M. Anwar HOSSAIN
Department of Biochemistry, University of Dhaka,
Dhaka-1000, Bangladesh.
(Received September 14, 1997)
Abstract
The regeneration
capacities of six selected Indica rice (Oryza sativa L.) cultivars
were studied through callus culture initiated from mature seeds. Mature
seeds of these varieties were used for callus induction. Plantlets
were obtained from the induced callus. Regeneration was found to be
the highest (100%) for BR-5 and the lowest (40%) for FR13A. Highest
number of plants per seed were obtained from BR-20 (23) and lowest
from BR-5 (3).
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