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Research
reveals that failure to repair the damage to the DNA structure,
such as single-strand breaks, double-strand breaks, pyrimidine
dimers, mismatched bases and modified bases, may result in
chromosomal translocation and interstitial deletion which
ultimately lead to genomic instability and cancer. These damages
in the DNA are induced either by exogenous or endogenous agents.
Interestingly, current research indicates that with appropriate
nutrition, cancer deaths can be avoided by eliminating such
damages to DNA structure. For instance, dietary deficiencies
in Zinc—which has an important role in transcription
factor function, antioxidant defence and DNA repair—can
contribute to single- and double-strand DNA breaks and oxidative
modifications to DNA that enhance the risk for cancer. It
means, by affording repairs to DNA damage through proper nutritional
practices, cancer deaths can be arrested.
A
lot of interest has thus emerged in researching the mechanics
of DNA damages. Existing literature indicates that among these
damages, double-strand breaks are the most dangerous lesions.
They are typically induced by internal agents such as the
pre-radicals which are the by-products of the cellular metabolism
or due to errors in DNA replication and external sources such
as x-rays and g-rays. These types of damages involve both
the strands of DNA that cause accumulation of genomic rearrangement
promoting tumorigenesis. These damages are, however, normally
repaired in two pathways: (1) Homologous Recombination (HR)
and (2) Nonhomologous DNA End Joining (NHEJ). NHEJ occurs
in all the phases of the cell cycle and is the predominant
repair mechanism in mammalian cells. The intricacies of these
two repair mechanisms as revealed by the current state of
research and the need for future research that can throw light
on how these DSB-responsive proteins suppress chromosomal
abnormalities and thereby cancer are reviewed by the authors,
Kishore K Chiruvella, Sritha K Sankaran, Monika Singh, Mridula
Nambiar and Sathees C Raghavan, in the article, "Mechanism
of DNA Double-Strand Break Repair".
Enzyme
production using submerged fermentation techniques has in
the recent past become a billion dollar business. Two such
important enzymes are cellulase and laccase which have many
industrial applications. The authors, K Balaraju, J Joel Gnanadoss,
S Arokiyaraj, P Agastian and V Kaviyarasan, in their article,
"Production of Cellulase and Laccase by Laccaria fraterna
and Pleurotus ostreatus under Submerged and Solid State
Fermentation", have explored the production of laccase
and cellulase from Laccaria fraterna and Pleurotus
ostreatus using both submerged and solid state fermentation
techniques. They found higher levels of laccase and cellulase
activity in cultures produced under solid state fermentation
than in submerged cultures. The authors also studied the effect
of different substrates such as wheat bran, rice bran, paddy
straw and sawdust on the production of cellulase and laccase
and found maximum activity of L. fraterna in the mixture
of wheat bran and paddy straw and that of P. ostreatus
both in sawdust and wheat bran.
Phosphate
(Pi) translocator and glucosyltransferases are the two important
enzymes in glucon biosynthesis. The authors, Godson O Osuji
and Tassine Brown, in their article, "Environment-Wide
Reprogramming of mRNAs Encoding Phosphate Translocator and
Glucosyltransferase in Relation to Cellulosic Biomass Accumulation
in Peanut", using the RNAs synthesized by Glutamate Dehydrogenase
(GDH) that are homologous to the mRNAs encoding glucosyltransferase
and Pi translocator as probes, investigated the influence
of environmental factors that induce the isomerization of
GDH on cellulosic biomass accumulation in peanuts and found
that they have up-regulated the mRNA encoding Pi translocator
by about eight-fold and down-regulated the mRNA encoding glucosyltransferase
by at least five-fold. As against this, the factors—3
NTPs, GTP—have up-regulated the mRNA encoding glucosyltransferase
by about seven-fold and down-regulated the mRNA encoding glucosyltransferase
by at least five-fold. According to the authors, these results
could be useful in environmentally manipulating plants to
produce modified cellulose especially for the bioenergy industries.
The
authors, Binita B Chaplot, Ashok M Dave and Yogesh T Jasrai,
in their article, "In vitro rapid propagation
of Aloe vera L., a High Valued Medicinal Plant Through
Rhizome and Axillary Bud Proliferation", have developed
protocols for propagation of Aloe vera through rhizome
and axillary buds. The findings revealed that Murashige and
Skoog (MS) medium with 4.4 µM BA with 2.88 µM IAA
and 0.98 µM IBA produced a maximum number of shoots on
rhizome explants and from axillary node explants. The successful
acclimatization of A. vera in field conditions proved
that in vitro propagation could successfully be used
to obtain elite propagules on a large-scale for cultivation
and industrial use.
The
authors, R Chakravarthy and A Sadanandam, in their article,
"Evaluation of Parameters for Genetic Transformation
Studies in Nicotiana tobaccum", have proposed
a successful experimental protocol on genetic transformation
to develop healthy transgenic gene expression in Nicotiana
tobaccum.
The
authors, P E Rajasekharan, S R Ambika and S Ganeshan, in their
article, "In vitro Regeneration and Slow Growth
Studies on Rauvolfia serpentina", have developed
protocols for in vitro regeneration of R. serpentina
from axillary meristems. Their studies also indicate that
MS medium containing 4.44 µM BA and 0.54 µM NAA
gives best shoot proliferation, while storage of vitroplants
in low temperature proves to be highly promising.
In
the last article, "A Survey on Antisense Oligonucleotides
Efficacy Prediction", Divya Mohan has reviewed the research
under antisense oligonucleotide technology that has come into
vogue to selectively modulate gene expression, with an emphasis
on different techniques that can be used for antisense oligonucleotide
efficacy prediction.
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GRK Murty
Consulting
Editor |
