|
Chronic
Exposure to Arsenic at Low Concentration Has Toxic Effect
in Human but Short-Term Exposure in Vitro Induces Apoptosis
-- Rajdeep Chowdhury ,
Suchandra Chowdhury , Paromita Roychoudhury, Chitra Mandal
and Keya Chaudhuri
Arsenic
is an environmental toxicant and a human carcinogen, but paradoxically
it has therapeutic effects too. A field survey, conducted
amongst the inhabitants of north 24 Parganas, West Bengal,
exposed to arsenic, shows the prevalence of different types
of arsenic induced skin lesions at exposure to low non-toxic
doses. The results reveal a significant preponderance of dermal
effects like hyperkeratosis and raindrop pigmentation at low
doses; however, little correlation was observed with the arsenic
exposure and arsenic level in hair, nail or urine of the exposed
subjects. Paradoxically, in vitro application of the
soluble most toxic and naturally prevalent form of arsenic,
sodium arsenite (NaAsO2), results in a different
outcome in human malignant melanoma cell A375. Interestingly,
2 µM
NaAsO2, the maximum dose that can be achieved in
blood plasma, led to induction of apoptosis at 72 h of treatment,
confirmed through Annexin V-PI dual staining and DNA content
analysis. Increase in reactive oxygen species (ROS) production,
loss of mitochondrial membrane potential, associated with
an activation of caspases were found to be the critical mediators
of apoptosis.
©
2008 The Icfai University Press. All Rights Reserved.
Characterization
of Some Popular Mulberry Cultivars of Karnataka Through RAPD
Analysis -- S Mahesh
and Geetha Bali
Mulberry which belongs
to the genus Morus is an economically important plant
that is used as the sole food for rearing silkworms. Existing
conventional methods of identification of different cultivars
are difficult due to close similarities. Here we have described
the use of polymerase chain reaction-based Random Amplified
Polymorphic DNA (RAPD) for developing cultivar specific markers
that can be employed in the identification of some popular
mulberry cultivars of Karnataka. Twenty-five decamer oligonucleotide
primers were screened for five different mulberry cultivars,
among which three primers scored 47 bands ranging from 500-5000
bp. PCR amplification with these primers yielded 1-10 bands
per primer. Genetic tree was constructed based on the band
score following Ward's method. In the present study, we have
also identified few putative cultivar specific RAPD markers
that could be useful in developing SCAR markers for further
studies in germplasm conservation and identification of mulberry
cultivars.
©
2008 The Icfai University Press. All Rights Reserved.
Phytochemical
Screening and Antifungal Activity of Cyperus esculentus
L. --
N Prakash and B Ragavan
Cyperus esculentus
L., a member of family Cyperaceae is an edible medicinal plant
which is used for various ailments such as hypochondriasis,
indigestion, nausea and fever. In the present study, the phytochemical
screening and antifungal activity of various extracts (such
as acetone, 50% ethanol (hydroethanol), chloroform and petroleum
ether) of C. esculentus L. tubers were evaluated. The
results showed the presence of various important secondary
metabolites such as alkaloids, flavonoids, terpenoids, phenols,
etc., in higher levels in hydroethanolic extract of the sample.
Hydroethanolic and acetone extracts showed maximum antifungal
activity against Candida albicans and Aspergillus
flavus. Chloroform and petroleum ether extract showed
maximum activity against A. flavus. Trichoderma
sp. was known to be resistant against all the extracts of
the sample.
©
2008 The Icfai University Press. All Rights Reserved.
RESEARCH
NOTE
MicroRNAs:
Novel and Potential Candidates for Cancer Therapy
-- D Karunagaran, P Sripriya and B N Prabhakar
MicroRNAs
(miRNAs) are a new class of non-protein-coding, endogenous,
small RNAs typically 21-23 nucleotide (nt) in length, evolutionarily
conserved in many organisms as disparate as yeast, fruit flies,
human and plants (Bartel, 2004). They play profound and pervasive
roles in manipulating genes involved in development, proliferation,
apoptosis and stress response in various eukaryotes (Ambros,
2004). Recent evidences demonstrate that aberrant miRNA expression
is a hallmark of tumor development, revealing that miRNA genes
could function as potential oncogenes and repressors in the
human body (He et al., 2005b; and Volinia et al.,
2006).
©
2008 The Icfai University Press. All Rights Reserved.
RESEARCH
NOTE
RNA
Interference and Functional Genomics: From Genes to Drug Discovery
-- Dashnamoorthy Ravi and Alex Bishop
Human
genome has been predicted to consist 69,073 genes, of which
an estimated 48,400 genes are believed to be transcribed,
out of which 22,740 transcripts are expected to be translated
into known and novel protein (www.ensembl.org). Extensive
informatics about the genome sequence of several species has
been accumulated so far and overlaps between such gene and
protein sequences across various species have also been computed.
As informatics about genomes continue to expand, the utility
for such data-pools is becoming realized as it is becoming
a need for functional genomics.
©
2008 The Icfai University Press. All Rights Reserved.
|
