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There are many plants in Kashmir valley which have been shown to
possess medicinal properties. Among them is Euphorbia helioscopia
which is known for its medicinal values. At present drug resistance
is a worldwide problem and much emphasis is being laid on the
natural plant sources to act as antibiotics which can overcome this
problem. Euphorbia helioscopia which is known for its medicinal
values has febrifuge and vermifuge activities in its roots and stem
respectively. The root is anti helminthic. The milky sap is applied
externally to skin eruptions. The seeds, mixed with roasted pepper,
have been used in the treatment of cholera and the oil from the
seeds has purgative properties. However, isolation of any
antibacterial protein has not been reported till date. The essence
of the work was to check the antibacterial activity of the plant
following its purification and characterization from leaves using
conventional protein purification techniques. The lectin is a
homodimer (Mr 65000Da), thermostable between 0 C- 40 C but exhibits
a narrow range of pH stability being optimally active at pH 7. The
lectin shows antimicrobial activity against P. aeruginosa,
K.pneumoniae and E. coli.
-galactosidases belong to glycosyl hydrolase family of
enzymes.These enzymes are widely distributed in nature.
-galactosidases have been implicated in many biological functions
like hydrolysis of dietary lactose, degradation of glycolipids and
proteoglycans, fruit ripening, cell elongation, storage
mobilisation and petal senescence. - galactosidase has proven as a
best alternative for elimination of lactose intolerance.The present
study was aimed at investigating the biochemical properties of
-galactosidases from apricots.Three isoenzymes( -gal I, -gal II and
-gal III) were obtained by salt fractionation and ion-exchange and
Sephadex G-100 column chromatography. -gal I, II and III showed
0.39, 0.52 and 0.30 units of activity respectively. The molecular
weight of -gal I, II an III as determined by gel filtration was
found to be 44.15,34.70 and 23.71 KDa respectively. The optimum pH
for the activity of different isozymes was between 4 and 6. The
isoenzymes were determined to be thermally stable upto 40oC. The Km
for -gal I was 1.85mM,1.7mM for -gal II and 1.19 for -gal III.The
Vmax for -gal I, -gal II aand -gal III was found to be 0.52,0.70
and 0.38umole/min respectively.
Lectins are carbohydrate-binding proteins of non-immune origin that
agglutinate cells or precipitate glycoconjugates.Based on
evolutionary and structural relatedness, seven lectin families have
been distinguished, of which legume lectins are the best
characterized. Lectins typically constitute a large fraction of the
total protein in most leguminous seeds and plant storage tissues
where they play an important role in several defense mechanisms. A
lectin from the seeds of Indigofera heterantha, member of family
leguminosae was isolated, purified, partially characterized and its
antimicrobial activity evaluated. The lectin is a homotetramer with
a molecular weight of about 70 KDa. The lectin shows a reasonable
temperature stability and is stable in the pH range of 2-9. It
demonstrates a remarkable antibacterial activity against E.coli,
K.pneumonia, S.aureus, and B.subtilis and also inhibits the growth
of phytopathogens Aspergillis niger, Aspergillis oryzie and
Fusarium oxysporum. These results point out that future findings on
applications of lectins isolated from leguminous plants can be of
great importance for clinical microbiology and possible therapeutic
applications.
Lectins are proteins or glycoproteins of non immune origin which
have a wide distribution in animals, plants, and microorganisms.
Their medicinal role extends from simple antimicrobial action to
anti- tumour properties.In view of the advancement in understanding
the potential medicinal role of the plant lectins, a lectin from
the leaves of Prunella vulgaris was isolated, purified, partially
characterized and its antimicrobial activity evaluated. The lectin
is specific for galactose and N-acetyl-galactosamine The molecular
weight of the lectin as determined by SDS-PAGE was 32500 Da and
that estimated from Sephadex G-100 gel filtration column was 65000
Da indicating that the purified lectin is a homodimer. The purified
lectin also shows a significant antimicrobial activity against the
infectious agents of some common diseases such as Salmonella typhi,
Klebseilla pnuemonea and Escherhia coli.
Plant lectins are a heterogeneous group of proteins or
glycoproteins that share in common their ability to recognize and
bind specific sugar residues. At present hundreds of plant lectins
have been isolated and characterized with respect to their
molecular structures and carbohydrate-binding specificities. Since
the unique biological properties of lectins can be exploited in the
investigation of numerous biochemical and cellular phenomena,
intense efforts are being made in many labs to isolate lectins with
unique and unusual sugar-binding specificities. The study deals
with the purification and partial characterization of a lectin from
Crotalaria pallida belonging to Leguminoseae. Conformational
changes and changes in biological properties by chemical
modification of the lectin are also a part of the study. The lectin
is a monomeric galactose and blood group A specific glycoprotein
with about 4% carbohydrate and a molecular weight of 43 kDa. The
activity yield of the lectin was about 4.6% with nearly three fold
purification. Conformational changes were investigated by gel
filtration, viscometery and UV absorption spectroscopy.
Zea mays (a C4 plant) can withstand high sulfur dioxide
concentrations up to 12.0 ppm without any harmful effects. Visible
injury symptoms appear only after exposure to sulfur dioxide
concentrations beyond 12.0 ppm. The pigments, proteins, amino acids
and starch decrease after exposure to higher concentrations of
sulfur dioxide. The free sugars, however, increase in response to
sulfur dioxide exposure. The activity of PEP - carboxylase is
inhibited non -competitively with respect to substrates, PEP and
Mg2+ but it is competitive with HCO3-.The high affinity of the
enzyme for HCO3- renders the replacement by sulfur dioxide more
difficult which results in decreased sensitivity towards sulfur
dioxide. NADP - malate dehydrogenase is inhibited uncompetitively
with respect to OAA and non - competitively with respect to NADPH.
The low inhibitory effect of sulfur dioxide on the enzymes is
indicated by high Ki values.In case of NADP - malic enzyme, sulfur
dioxide shows a non - competitive inhibition with respect to NADP+
but a competitive one with respect to Mg2+. With respect to malate,
the inhibition is partially competitive.
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