It's easier to patent plants than to publish research.
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Animals↗
Biomedical subjects
U C Lavania
Publications and source records attributed to U C Lavania.
In situ chromosomal localization of rDNA sites in "Safed Musli" Chlorophytum ker-gawl and their physical measurement by fiber FISH.
Fluorescence In Situ Hybridization (FISH) technique has been applied on somatic chromosomes and extended DNA fibers in the medicinally important species of Chlorophytum to elucidate physical localization and measurement of the rDNA sites using two rRNA multigene families homologous to 45S and 5S rDNA. The two species of Chlorophytum, namely C. borivillianum and C. comosum, both with 2n = 28, reveal diversity for copy number and localization of rDNA sites. C. borivillianum is comprised of five 45S-rDNA sites:one each in the secondary constriction region of chromosomes 7, 8, 9; one in the subtelomeric region of the short arm of chromosome 2 and the telomeric region of the short arm of chromosome 12; and one 5S-rDNA site in the subtelomeric region of the long arm of chromosome 1. In C. comosum, there are three 45S-rDNA sites (one each in the short arm of chromosomes 12, 13, and 14) and two 5S-rDNA sites (in the secondary constriction regions of chromosomes 2 and 13). Fiber FISH analysis conducted on extended DNA fibers revealed variation in the size of continuous tandem strings for the two r-DNA families. Taking the standard value of native B DNA equivalent to 3.27 kb for 1 mum, it was estimated that the physical size of continuous DNA strings is of the order of approximately 90 kb, 180 kb, and 300 kb for 45S-rDNA and of the order of 60 kb, 150 kb for 5S-rDNA in C. comosum, grossly in correspondence to their respective physical sizes at metaphase.
Asparagaceae↗
Extended chromatin and DNA fibers from active plant nuclei for high-resolution FISH.
The conventional protocol for isolation of cell wall free nuclei for release of DNA fibers for plants involves mechanical removal of the cell wall and separation of debris by sieve filtration. The mechanical grinding pressure applied during the process leaves only the more tolerant G(1) nuclei intact, and all other states of active nuclei that may be present in the target tissues (e.g., leaf) are simply crushed/disrupted during the isolation process. Here we describe an alternative enzymatic protocol for isolation of nuclei from root tip tissue. Cell wall free nuclei at a given stage of cell cycle, free of any cell debris, could be realized in suspension that are fit for preparation of extended fibers suitable for fiber FISH applications. The protocol utilizes selective harvest of active nuclei from root tip tissue in liquid suspension under the influence of cell wall-degrading enzymes, and provides opportunities to target cell cycle-specific nuclei from interphase through division phase for the release of extended DNA fibers. Availability of cell cycle-specific fibers may have added value in transcriptional analysis, DNA:RNA hybridization, visualization of DNA replication and replication forks, and improved FISH efficiency.
Cell Cycle↗
High resolution FISH to delineate contiguous and small DNA sequences.
Somatic and meiotic metaphase, and pachytene chromosomes were subjected to DNA: DNA in situ hybridization to elucidate relative resolution of FISH signals for weak/contiguous hybridization sites. Hybridization with a '350 family' rye repetitive DNA probe pSc 200 characteristically differentiated the rye chromosome 5 from the rest of the complement on account of two small terminal homologous sites in the long arm, resolution of which is substantially improved using pachytene. Higher resolution of the two weak hybridization sites; a very small distal and a small proximal, is unequivocally demonstrated in the FISH painted 5RL examined at pachytene in the 5AS/5RL wheat background. Additionally this probe exhibits a large block of distal telomeric hybridization site in 5RS, followed by a more prominent proximal site homologous to '610 family' rye repetitive probe pSc 250. Precise denaturation - hybridization incubation and post hybridization stringency washing facilitates spatial resolution of contiguous repetitive rye probes pSc 200 and pSc 250, and physical localisation of small RFLP probe xpr 115 of wheat on barley chromosomes.
Chromosome Painting↗
Duration of cell cycle, onset of S phase and induced mitotic synchronisation in seeds of opium poppy, Papaver somniferum L.
Duration of mitotic cell cycle and its component phases in root-tip meristem of P. somniferum was determined following autoradiographic detection of mitotic rythms during the traverse of cell cycle. The mitotic cycle time thus estimated was found to be 12.6h of which the distribution of component phases was G1 = 1.75 h, S = 6.3 h, G2 = 3.75 h and division phase (M) = 0.8 h. Dry seeds were metabolically activated by soaking in water to show that the first batch amongst the asynchronous population of cells in the seeds enters into S phase after 18 h of such soaking at 16 degrees C. Mitotic synchrony to the tune of 80% could be realised when such presoaked seeds were administered 5 mMole hydroxyurea for 20 h at 16 degrees C.
Cell Cycle↗
An interphase model for mitotic chromosome organization in eukaryota.
A model for the spatial relationship of the arrangement of the chromosomes in the nucleus in eukaryota is presented. Evidence is derived from light and electron microscopic studies, application of autoradiographic and banding techniques; on the organization, structure and behaviour of chromosomes during interphase and other stages of cell cycle. This model visualizes the entire chromosomal DNA as a single uninemic multirepliconic continuum where the chromosomes with their centromeres and telomeres have a predetermined arrangement among themselves as well as in relation to the nucleolus and nuclear membrane. This orderly arrangement is presumably maintained through interchromosomal connections. The impact of this model on the interpretation of various cytogenetic phenomena is discussed.
Animals↗
A quick squash method for permanent cytological preparations.
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Adhesives↗
Trypsin-orcein banding in plant chromosomes.
A convenient and quick method using trypsin-orcein for banding plant chromosomes (O-banding) is suggested. The technique is directly applicable to meristematic tissues (e.g. root tips) and involves the treatment of root tips with 1-2% solution of trypsin either in buffer or in 0.5 N HCl for 5-10 minutes at 37 C or for 30-60 minutes near 0 C followed by staining with 1.5% acetic orcein: 1 N HCl (19:1). Dark staining bands are reproducible and species specific. These bands possibly represent specific DNA-protein-dye interaction.
Chromosome Banding↗