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81.
Genetic toxicology studies play a central role in the development and marketing of new chemicals for pharmaceutical, agricultural, industrial, and consumer use. During the discovery phase of product development, rapid screening tests that require minimal amounts of test materials are used to assist in the design and prioritization of new molecules. At this stage, a modified Salmonella reverse mutation assay and an in vitro micronucleus test with mammalian cell culture are frequently used for screening. Regulatory genetic toxicology studies are conducted with a short list of compounds using protocols that conform to various international guidelines. A set of four assays usually constitutes the minimum test battery that satisfies global requirements. This set includes a bacterial reverse mutation assay, an in vitro cytogenetic test with mammalian cell culture, an in vitro gene mutation assay in mammalian cell cultures, and an in vivo rodent bone marrow micronucleus test. Supplementary studies are conducted in certain instances either as a follow-up to the findings from this initial testing battery and/or to satisfy a regulatory requirement. Currently available genetic toxicology assays have helped the scientific and industrial community over the past several decades in evaluating the mutagenic potential of chemical agents. The emerging field of toxicogenomics has the potential to redefine our ability to study the response of cells to genetic damage and hence our ability to study threshold phenomenon. 相似文献
82.
Sudhir Gupta Anshu Agrawal Sudhanshu Agrawal Houfen Su Sastry Gollapudi 《Immunity & ageing : I & A》2006,3(1):5-8
Aging is associated with a paradox of immunodeficiency and inflammation (an evidence of hyperactive immune system). Apoptosis
is associated with cellular depletion and suppression of inflammatory response. In this brief review, we will present evidence
for the role of increased apoptosis in immunodeficiency and paradoxical increased inflammation associated with human aging.
In particular, a role of apoptotic cells in failure to generate anti-inflammatory responses and directly activating inflammatory
responses will be discussed. 相似文献
83.
84.
Sowmya Handenahally Reddy Rajesh Kumar Singhal Maria Vera Jesus DaCosta Sumanth Kumar Kambalimath Mavinahalli P Rajanna Raveendran Muthurajan Amitha Mithra Sevanthi Trilochan Mohapatra Neelamraju Sarla Viswanathan Chinnusamy Gopala Krishnan S Ashok Kumar Singh Nagendra Kumar Singh Rameshwar Prasad Sharma Niranjana Pathappa Sreeman M. Sheshshayee 《Physiologia plantarum》2020,169(2):194-213
Saving water and enhancing rice productivity are consensually the most important research goals globally. While increasing canopy cover would enhance growth rates by higher photosynthetic carbon gain, an accompanied increase in transpiration would have a negative impact on saving water as well as for sustainability under water-limited conditions. Increased water use efficiency (WUE) by virtue of higher carbon assimilatory capacity can significantly circumvent this trade-off. Here, we report leaf mass area (LMA) has an important canopy architecture trait which when combined with superior carboxylation efficiency (CE) would achieve higher water productivity in rice. A set of 130 ethyl methanesulfonate induced mutants of an upland cultivar Nagina-22 (N22), was screened for leaf morphological traits leading to the identification of mutants differing in LMA. The wild-type, N22, along with a selected low-LMA (380–4-3) and two high-LMA mutants (392–9-1 and 457–1-3), all with comparable total leaf area, were raised under well-watered (100% Field Capacity (FC)) and water-limited (60% FC) conditions. Low Δ13C and a higher RuBisCO content in high-LMA mutants indicated higher carboxylation efficiency, leading to increased carbon gain. Single parent backcross populations developed by crossing high and the low-LMA mutants with N22, separately, were screened for LMA, Δ13C and growth traits. Comparison of dry matter accumulation per unit leaf area among the progenies differing in LMA and Δ13C reiterated the association of LMA with CE. Results illustrated that high-LMA when combined with higher CE (low Δ13C) lead to increased WUE and growth rates. 相似文献
85.
B. Bhaskar Gollapudi Diane J. Sutcliffe Anil K. Sinha 《In vitro cellular & developmental biology. Plant》1986,22(11):681-684
Summary Rat lymphocyte cultures were initiated in minimal essential medium containing 0, 0.01, 1.0, or 10 mg/l of folic acid to investigate
the influence of folic acid on cell kinetics, chromosome aberration, and sister chromatid exchange (SCE) frequencies. No significant
difference was observed between cultures with and without folic acid in mitotic index or cell cycle kinetics as judged by
the numbers of average lymphocyte divisions. However, a sequential reduction in the number of chromatid gaps occurred as the
concentration of folic acid increased. On the other hand, addition of folic acid did not significantly affect the SCE frequency.
Although folic acid does not seem to alter SCE formation, its significant influence in the reduction of chromatid gaps suggests
that caution should be exercised in selecting a medium regarding folic acid content especially because gaps alone are produced
by certain dose levels of some chemical clastogens. 相似文献
86.
Splenic B cells from CBA/N mice acquire responsiveness to anti-immunoglobulin after a brief treatment with pronase 总被引:1,自引:0,他引:1
Although splenic B cells of CBA/N mice do not synthesize DNA in response to anti-mouse IgM (mu-chain specific), the cells respond readily to Sepharose linked anti-mu. Subsequent to a brief treatment with pronase, CBA/N splenocytes exhibited anti-mu-mediated DNA synthesis at 40 to 100% of the DNA synthetic capacity detected with Sepharose linked anti-mu. Furthermore, spleen cell populations treated with anti-Thy-1.2 and complement or populations purified on anti-immunoglobulin-coated Petri plates (greater than 90% surface immunoglobulin positive) acquired responsiveness to anti-mu after pronase treatment. 相似文献
87.
Lester A. Mitscher Sitaraghav R. Gollapudi Ish K. Khanna Steven D. Drake T. Hanumaiah T. Ramaswamy Kolluru V. Jagannadha Rao 《Phytochemistry》1985,24(12):2885-2887
Flemiflavanone-D from Flemingia stricta is active in vitro against Staphylococcus aureus and Mycobacterium smegmatis. Reexamination and interpretation of its spectral properties required revision of its molecular formula to C25H28O6 and its structure to 2S-5,7,4′-trihydroxy-6-γ,γ-dimethylallyl-3′-γ,γ-dimethylallyl-oxidoflavan-4-one. The new structure was confirmed when reaction with chlorotrimethylsilane sodium iodide in acetonitrile deoxygenated and cyclized flemiflavanone-D to the known dicycloeuchrestaflavanone A. The absolute stereochemistry of flemiflavanone-D was established to be 2S by circular dichroism measurements. 相似文献
88.
J M Charles H C Cunny R D Wilson J S Bus T E Lawlor M A Cifone M Fellows B Gollapudi 《Mutation research》1999,444(1):207-216
2,4-dichlorophenoxyacetic acid and several of its derivatives (collectively known as 2,4-D) are herbicides used to control a wide variety of broadleaf and woody plants. The genetic toxicity in vitro of 2,4-D and seven of its salts and esters were examined by employing gene mutation in bacteria (Ames test) and induction of DNA damage and repair in rat hepatocytes. In addition, an in vivo unscheduled DNA synthesis (UDS) assay was performed on 2,4-D. There were no indications of genotoxic potential for 2,4-D acid, or any of its derivatives, in these assays. These results are consistent with the reported lack of carcinogenic potential for 2,4-D in both mice and rats. 相似文献
89.
Spontaneous cytogenetic aberrations were analyzed in bone-marrow cells and cultured peripheral lymphocytes from the same animals. No significant differences in the total number of cells with aberrations or total aberrations were detected between the bone-marrow cells and cultured lymphocytes. It was concluded that short-term culture does not contribute significantly to in vivo aberration yield within the experimental conditions used. 相似文献