P N BHADURI

P C BOSE

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Cyto-genetical investigations in some common cucurbits, with special reference to fragmentation of chromosomes as a physical basis of speciation.

Journal of Genetics

Momordica charantia L.commonly known as bitter gourd is a widely cultivated cash crop in India with immense medicinal values. India has been one centre of diversification of two prominent taxonomic varieties viz. long-fruited variety, M. charantia var. charantia (MCC) and small-fruited variety, M. charantia var. muricata (MCM). Momordica species have long been known not to be amenable to conventional cytological techniques. After thorough technical standardization, karyotype variation between the two varieties as well as different populations of the same variety was compared and we primarily structured karyotypes of MCC and MCM populations that conformed to diploid count of 2n = 22 with slightly greater chromosome size in MCM (1.32μm–3.24 μm) than MCC (1.27μm–3.07 μm). Significant differences in genome size between MCC and MCM was also confirmed by flow cytometry for the first time in the two varieties of the species. Pronounced intraspecific dissimilarity in somatic chromosomes was established by EMA-Giemsa method revealing four nucleolar chromosomes in MCC populations and six nucleolar chromosomes in MCM populations. This difference in varieties was substantiated by fluorochrome banding which revealed four and six distal CMA+ve signals in MCC and MCM respectively. Detailed inter- and intra- karyomorphometric evaluation ascertained higher tendency of karyotype asymmetry in MCC. EMA-DAPI technique was applied for meiotic analysis in MCC (n = 11) and MCM (n = 11) populations providing indications of regular meiotic behavior. These results will benefit the classification, the genetic basis of domestication and the genome studies of this widely cultivated cash crop. © 2018 Elsevier B.V.

Scientia Horticulturae

Cytogenetics of two Indian varieties of Momordica charantia L. (bittergourd)

Coccinia grandis is a widely distributed dioecious cucurbit in India, with heteromorphic sex chromosomes and X-Y sex determination mode. The present study aids in the cytogenetic characterization of four native populations of this plant employing distribution patterns of 45S rDNA on chromosomes and guanine-cytosine (GC)-rich heterochromatin in the genome coupled with flow cytometric determination of genome sizes. Existence of four nucleolar chromosomes could be confirmed by the presence of four telomeric 45S rDNA signals in both male and female plants. All four 45S rDNA sites are rich in heterochromatin evident from the co-localization of telomeric chromomycin A (CMA)+ve signals. The size of 45S rDNA signal was found to differ between the homologues of one nucleolar chromosome pair. The distribution of heterochromatin is found to differ among the male and female populations. The average GC-rich heterochromatin content of male and female populations is 23.27 and 29.86 %, respectively. Moreover, the male plants have a genome size of 0.92 pg/2C while the female plants have a size of 0.73 pg/2C, reflecting a huge genomic divergence between the genders. The great variation in genome size is owing to the presence of Y chromosome in the male populations, playing a multifaceted role in sexual divergence in C. grandis. © 2015, Springer-Verlag Wien.

Protoplasma

Chromosomal localization of 45S rDNA, sex-specific C values, and heterochromatin distribution in Coccinia grandis (L.) Voigt

The family Cucurbitaceae showcases a wide range of sexual phenotypes being variedly regulated by biological and environmental factors. In the present context, we have tried to assemble reports of cytogenetic investigations carried out in cucurbits accompanied by information on sex expression diversities and chromosomal or molecular basis of sex determination in dioecious (or other sexual types, if reported) taxa known so far. Most of the Cucurbitaceae tribes have mixed sexual phenotypes with varying range of chromosome numbers and hence, ancestral conditions become difficult to probe. Occurrence of polyploidy is rare in the family and has no influence on sexual traits. The sex determination mechanisms have been elucidated in some well-studied taxa like Bryonia, Coccinia and Cucumis showing interplay of genic, biochemical, developmental and sometimes chromosomal determinants. Substantial knowledge about genic and molecular sex differentiation has been obtained for genera like Momordica, Cucurbita and Trichosanthes. The detailed information on sex determination schemes, genomic sequences and molecular phylogenetic relationships facilitate further comprehensive investigations in the tribe Bryonieae. The discovery of organ identity genes and sex-specific sequences regulating sexual behaviour in Coccinia, Cucumis and Cucurbita opens up opportunities of relevant investigations to answer yet unaddressed questions pertaining to floral unisexuality, dioecy and chromosome evolution in the family. The present discussion brings the genera in light, previously recognized under subfamily Nhandiroboideae, where the study of chromosome cytology and sex determination mechanisms can simplify our understanding of sex expression pathways and its phylogenetic impacts. © 2015, Indian Academy of Sciences.

Dynamics of sex expression and chromosome diversity in Cucurbitaceae: a story in the making

Analyses of the structure and behaviour of chromosomes and estimation of 4C nuclear DNA in both male and female plants of Coccinia indica and Trichosanthes dioica were made. In male and female plants of T. dioica had identical chromosome numbers. There was remarkable similarity between sexes in chromosome morphology, number of secondary constrictions and total chromosome length, as well as the amount of 4C DNA. In absence of any detectable chromosomal differences it may be argued that the sex determination in this species is principally controlled at the autosomal level. The karyotypes of male and female individuals were not markedly different in C. indica, except for the sex chromosomes. The total chromosome length was slightly more in male as compared to female plant. There was a corresponding difference in 4C DNA values. The differences in chromosome size between sexes of C. indica reflected additional chromatin rather than differential condensation. The heterochromatic nature of long sex chromosome was also indicated in its staining behaviour. The total chromosome length, average chromosome length and the 4C nuclear DNA values of both males and females of annual T. dioica were comparatively higher than those of the related perennial, C. indica. © 1991, Japan Mendel Society, International Society of Cytology. All rights reserved.

Fulltext

CYTOLOGIA

Chromosome Studies and Nuclear DNA in Relation to Sex Difference and Plant Habit in Two Species of Cucurbitaceae

1. Cytological studies on Trigonella foenum-graecum and two species of Melilotus, namely M. indica and M. alba, have been performed. All are characterized by 2n = 16 chromosomes. 2. Detailed karyotype analysis has been performed and minor differences are noticed between different species. The members of these two genera show much resemblance in the gross morphology of their chromosomes. 3. Meiosis has been worked out in detail in all the species. Distinct secondary association of bivalents has been ohserved in Melilotus alba and three chromosomes have been considered as constituting the basic complement of its ancestral forms. In other two species, tendency of association of bivalents has been noticed. 4. On the basis of the cytological data, the two genera seem to be very much related. In view of slight difference in their external morphology, the two genera may be treated as sub-genera under one genus. In any case, data from other aspects of study are necessary for assigning their correct status. 5. Slight somatic irregularities noticed in a number of individuals have been considered to be gradually eliminated in competition with the normal ones, specially in view of the perfect sexual reproduction of these species. © 1958 Taylor and Francis Group, LLC.

Caryologia

A comparative study on the cytology of a few species of two allied genera trigonella and melilotus

Cytological analysis of structural hybridity inRhoeo discolor hance

Journal of the agricultural chemical society of Japan

Studies on the Cell-Wall Constituents of Soy-Bean. (II)

The Canadian Journal of Economics and Political Science

Why Study Business History?

The New England Quarterly

John Quincy Adams's Letters on Silesia

Industrial & Engineering Chemistry Analytical Edition

An Improved Slow-Combustion Pipet for Gas Analysis

Cyto-genetical investigations in some common cucurbits, with special reference to fragmentation of chromosomes as a physical basis of speciation

Journal	Journal of Genetics
Publisher	-
ISSN	0022-1333