Browsing by Author "Y.B.K. Chowdary"

Now showing 1 - 18 of 18

A new species of Tetraspora (T. apiocystioides sp. nov.) cand its ytology
(Kluwer Academic Publishers, 1967) Y.B.K. Chowdary; G. Suryanarayana; Y.S.R.K. Sarma
A new species of Tetraspora (T. apiocystioides sp. nov.) has been described with some observations on its nuclear cytology. The chromosome number determined for this species is 16. © 1967 Dr. W. Junk Publishers.
Cell Division in Pennate Diatoms
(1991) Bandla S. Giri; Y.B.K. Chowdary
General pattern of the process of mitotic division was studied in thirty seven pennate diatoms. Even though normal mitotic division takes place in diatoms it resembles with that of animal cell division in having ring-like arrangement of metaphase chromosomes and cell furrow cleavage of cytoplasm. Most of the diatoms follow Mac Donald—Pfitzers hypothesis of size reduction after cell division in each generation. © 1991, Japan Mendel Society, International Society of Cytology. All rights reserved.
Cytological Observations on some Chlorococcoid Green Algae
(1967) Y.B.K. Chowdary
[No abstract available]
Cytological observations on the material of Boergesenia forbesii (Harv.) Feldmann from the South and West Coast of India
(Kluwer Academic Publishers, 1975) S.J. Singh; Y.B.K. Chowdary
[No abstract available]
Cytological Observations on Two Siphonaceous Marine Algae
(1970) Y.B.K. Chowdary
[No abstract available]
Cytological Studies on Some Chlorococcoid Green Algae
(1983) U.N. Rai; Y.B.K. Chowdary
In the present communication nine species belonging to eight Chlorococcalean genera and one belonging to Chlorosarcinaceae of Chlorosarcinales have been collected locally, isolated, and grown in cultures. All the algae have been subjected to karyological investigation. Their studies have shown the existence of cytologícal races in the genus Ankistrodesmus. Based on the chromosome number and karyological features the cytotaxonomic aspects of the algae have been discussed. It was concluded that taxonomic treatment on the basis of cytological data is possible only when a large number of species of each genus were undertaken and studied together. © 1983, Japan Mendel Society, International Society of Cytology. All rights reserved.
Effects of metabolic inhibitors on the calcification of a freshwater green alga Gloeotaenium loitlesbergarianum Hansgirg. 2. Effects of some inhibitors of protein synthesis
(Oxford University Press, 1981) P. V. Devi Prasad; Y.B.K. Chowdary
The effects of five inhibitors of protein synthesis, viz. streptomycin, aurin tricarboxylic acid, tetracycline, chloramphenicol, and cycloheximide, on the calcification of Gloeotaenium loitlesbergarianum Hansgirg, a freshwater green alga were studied. Streptomycin had no effect while aurin tricarboxylic acid at 50 μg ml-1 and tetracyline, chloramphenicol and cycloheximide at 20 μg ml-1 completely inhibited calcification in the alga. High concentrations of chloramphenicol and cycloheximide were not completely inhibitory when added 26 h and 32 h respectively after the material was incubated in the induction medium. It is concluded that the effects by these substrates are the results of inhibition of protein synthesis, which is directly or indirectly linked to calcification. © 1981 Annals of Botany Company.
Effects of metabolic inhibitors on the calcification of a freshwater green alga, Gloeotaenium loitlesbergarianum Hansgirg. 1. Effects of some photosynthetic and respiratory inhibitors
(Oxford University Press, 1981) P. V. Devi Prasad; Y.B.K. Chowdary
The effect of a number of metabolic inhibitors on the calcification of Gloeotaenium loitlesbergarianum Hansgirg, a freshwater green alga, was studied. The inhibitors used were methylamine, trimethylamine, mercuric chloride, imidazole, fluoride, arsenate, atrazine, DCMU and dinitrophenol. The effects of these inhibitors show that transport, or stimulation of respiratory carbon dioxide evolution inhibits calcification. Calcification in Gloeotaenium is, at least partly, due to a local rise in pH as a result of photosynthetic carbon dioxide assimilation. There is also some evidence that, apart from its role in carbon dioxide assimilation, photosynthesis supplies the additional energy needed for calcification. © 1981 Annals of Botany Company.
Factors influencing the calcification of Gloeotaenium loitlesbergarianum Hansg.
(1979) P.V. Devi Prasad; Y.B.K. Chowdary
[No abstract available]
Growth and mineral nutrition of two Chlorococcalean algae
(Kluwer Academic Publishers, 1981) Thresiamma Mathew; Y.B.K. Chowdary
The effect of composition of the medium and pH on the growth of Pediastrum duplex Meyen and Dictyosphaerium pulchellum Wood was studied. Both species showed preference to alkaline conditions. The ammonium nitrate grown colonies of D. pulchellum lacked mucilage and showed a more compact form, resembling D. pulchellum var. minitum Deflandre. From this it appears that D. pulchellum var. minitum is a nutritional variant of the species and not a stable variety. © 1981 Dr W. Junk Publishers.
Karyological Studies on Some Indian Charophyta
(1992) B.V.S. Subrahmanyam; Y.B.K. Chowdary
Cytological investigations on two taxa of Chara Linn. (C. vulgaris var. gymnophylla f. grovesii and C. zeylanica var. sejuncta f. formosa) and a taxon of Nitella Ag. Leonh. (N. heterodactyla) were carried out. Nuclear events conformed to the standard pattern of mitosis described. The chromosome numbers determined are n=35 for C. vulgaris var. gymnophylla f. grovesii, n=42 for C. zeylanica var. sejuncta f. Formosa and n=18 for N. heterodactyla. All the three taxa were investigated for the first time and are new reports. © 1992, Japan Mendel Society, International Society of Cytology. All rights reserved.
Karyology of Gelidiella acerosa (Forsskal) Feldmann et Hamel
(1991) P.V. Subba Rao; K. Subbaramaiah; Y.B.K. Chowdary
In Gelidiella acerosa from Ervadi the diploid chromosome number 2n=12, with haploid number n=6 is discernible. Bivalents were observed in the dividing tetraspore mother cells. In situ germination of tetraspore mother cells dircetly by mitotic division points to apomeiotic propagation in this species. The occurrence of two cytotypes in the species suggests the existence of a polyploid series. © 1991, Japan Mendel Society, International Society of Cytology. All rights reserved.
Karyology of Nitella from South India
(1992) B.V.S. Subrahmanyam; Y.B.K. Chowdary
Karyological investigations on four taxa of Nitella have been carried out. The chromosome counts recorded are all new records to the respective taxa. Chromosome numbers are n=9, 27, 12 and 9 to Na furcata subspa flagellifera f. flagellifera RDW, Na furcata subsp. megacarpa f. megacarpa (T. F. A.) RDW, N. pseudoflabellata var. elegans (Pal) RDW and N. gracilis f. intermedia (Nordst.) RDW, respectively. N. graeilis f. intermedia is karyologically investigated from India for the first time. © 1992, Japan Mendel Society, International Society of Cytology. All rights reserved.
Karyology of the Genus Cyclotella Kütz. (Bacillariophyta)
(1991) Bandla S. Giri; Y.B.K. Chowdary
Four freshwater centric diatom taxa, Cyclotella glomerata, C. striata, C. meneghiniana f. unipunctata and C. catenata were investigated karyologically and their important karyological features have been described and discussed. First two taxa contained same chromosome number 2n=12 while C. meneghiniana f. unipunctata and C. catenata revealed 2n=18 and 24 chromosomes, respectively. Chromosomes did not show structural organization and appear like either small or large dots ranging from 0.25 to 1.8 µm in size. Chromosomes organize into either a ring or plate at metaphase in the equatorial region. © 1991, Japan Mendel Society, International Society of Cytology. All rights reserved.
Observations on the cytology of cylindrocapsa scytonemoides randhawa
(1963) Y.B.K. Chowdary
The cytology of Cylindrocapsa scytonemoides has been investigated. The chromosome number is 36. Out of these one of the chromosomes, is considerably longer (2.5μ) in comparison with the rest. The septum initiation takes place in telophase which is unlike the one reported in C. involuta. The nuclear behaviour and the morphology of the chromosomes are in general agreement with those of the other members of the Ulotrichales so far studied. Further the germlings of this alga have attaching discs which are similar to Uronema. In view of these findings the systematic position of the alga has been discussed. © 1963, Japan Mendel Society, International Society of Cytology. All rights reserved.
On the Cytology of Two Species of Dictyosphaeria Decaisne
(1974) Shivaji Singh; Y.B.K. Chowdary
Two species of Dictyosphaeria (i.e. D. covernosa (Forsk.) Borgs, and D. intermedia var. solida) were collccted from Indian coasts. A comparativc study of their morphological and cytologicat featurcs has rcvcalcd that thcsc two species are morphologically and cytologicaily distinct. The chromosome numbers dctermined for D. intermedia var. solida and D. cavernosa are 14 and 24 respectively. © 1974, Walter de Gruyter. All rights reserved.
Polymorphism in gloeotaenium (Chlorococcales, Chlorophyceae)
(Kluwer Academic Publishers, 1981) P.V. Devi Prasad; Y.B.K. Chowdary
Morphological variations of Gloeotaenium loitlesbergarianum Hansgirg were studied both in cultures and in nature. In cultures, the alga exhibits considerable variation in the number of cells per colony, ranging from unicells to colonies with more than four cells. The characteristic band was also absent in cultures. In nature, colonies resembling the culture material of Gloeotaenium also occur. The morphology of the alga varies depending on the nature and composition of the nutrients available. The study shows that Gloeotaenium may exhibit polymorphism in nature as well. © 1981 Dr W. Junk b.v. Publishers.
The chromosome numbers of some species of the genus stigeoclonium kuetz
(1967) Y.B.K. Chowdary
Six species of Stigeoclonium have been collected from nature and also grown in laboratory cultures. The chromosome numbers for six species of Stigeoclonium have been determined. They are as follows: S. variabile (6), S. fasciculare (7), S. stagnatile (8), S. aestivale (9), S. elongatum (10), and S. amoenum var. amoenum (12) The importance of this study in the systematic determination of the species of Stigeoclonium has been discussed. © 1967, Japan Mendel Society, International Society of Cytology. All rights reserved.