Showing papers by "Annamalai University published in 1988"
TL;DR: Bacterial load of the surrounding medium and type of food governed the distribution of luminous microbiota in fish, and Luminous microflora associated with the host showed seasonal variation.
Abstract: Luminous bacteria harboured in the skin, gill and gut of the fishes Mugil cephalus and Tachysurus arius were studies. Within the gut, the distribution of bacteria was studied regionwise, i.e., foregut, midgut and hindgut. In M. cephalus, maximum luminous bacterial population density was observed in the hindgut and minimum was found in the foregut. In T. arius, maximum luminous bacterial population density was recorded in the hindgut and minimum was found in the midgut. Luminous microflora associated with the host showed seasonal variation. Bacterial load of the surrounding medium and type of food governed the distribution of luminous microbiota in fish. Vibrio harveyi and V. fischeri were the two species identified, the former accounting for the majority of the isolates.
19 citations
01 Aug 1988
TL;DR: Stored paddy samples collected from 3 different storehouses in Tamil Nadu and threshed rice grains were assayed for the extent of fungal contamination by blotter and dilution plate methods and cultures of fungi isolated from stored samples were subjected to chemical extraction for aflatoxins.
Abstract: Stored paddy (150 samples) collected from 3 different storehouses in Tamil Nadu and threshed rice grains (20 samples) from local warehouses and retailers were assayed for the extent of fungal contamination by blotter and dilution plate methods. The contaminated samples that fluoresced in UV light and cultures of fungi isolated from stored samples were subjected to chemical extraction for aflatoxins. Aflatoxin B1 was detected in 7 out of 17 isolates ofAspergillus flavus and 1 out of 6Aspergillus parasiticus. Moisture content of the samples was correlated with the number of fungi isolated and the type of storehouse from which the samples were collected.
12 citations
01 Jun 1988
TL;DR: The luminous bacteriaVibrio harveyi and V fischeri degrade cellulose Cellulase activity was high when carboxymethyl cellulose and cellobiose were used as substrates but low with cellulose powder as mentioned in this paper.
Abstract: The luminous bacteriaVibrio harveyi andV fischeri degrade cellulose Cellulase activity was high when carboxymethyl cellulose and cellobiose were used as substrates but low with cellulose powder The role of these microbes in the digestion of food material in fish gut is also discussed
12 citations
TL;DR: Karyotypes in the family show differences in absolute chromosome size indicating changes in nuclear DNA in evolution, and the primary basic number of the family may be n=8 and from this other basic numbers should have originated by means of aneuploidy and euploidsy.
Abstract: The chromosome number of 18 species coming under 6 genera of Cyperaceae from South India has been studied. Chromosome numbers determined in the present study range from 2n=16 to 2n=96.Chromosome numbers determined in the present study and those reported previously in the family reveal the presence of a continuous series of basic numbers between n=8 to n=48. The primary basic number of the family may be n=8 and from this other basic numbers should have originated by means of aneuploidy and euploidy. Along with these karyotype alterations of chromosomes also play important role in evolution.Karyotypes in the family also show differences in absolute chromosome size indicating changes in nuclear DNA in evolution.
11 citations
TL;DR: 16 taxa coming under 10 families occurring in the Mangroove forests of Tamilnadu, have been studied cytologically, of which first record of chromosome number has been made in lanceolate leaf type.
Abstract: 16 taxa coming under 10 families occurring in the Mangroove forests of Tamilnadu, have been studied cytologically, of which first record of chromosome number has been made in lanceolate leaf type of Sesuvium portulacastrum, Rhizophora candelaria, Ceriops roxburghiana, Bruguiera conjugata, Avicennia marina, Suaeda maritima, S. monoica, Arthrocnemum fruticosum, Aegiceros corniculatus and Ilysanthes tenuifolia.n=18 may be the common primary basic number of the vegetation and from this the basic numbers 8, 9, 11, 12 and 15 should have arisen by decrease of chromosome numbers and the basic numbers n=19, 20, 22 should have originated by increase of chromosome numbers.Smaller size of chromosomes and mostly chromosomes with submedian and subterminal constrictions are the other advanced cytological characters of the mangroove vegetations studied.
10 citations
5 citations
TL;DR: The first record of chromosome number has been made in Cleome tenella, C. divaricata and Capparis brevispina in South Indian Capparidaceae as discussed by the authors.
Abstract: Cytotaxonomical studies have been made in 18 species coming under 6 genera of South Indian Capparidaceae, of which first record of chromosome number has been made in Cleome tenella, C. felina, C. aspera, Cadaba triphylla, Capparis brevispina, C. diversifolia, C. rotundifolia and C. divaricata.The basic chromosome number ranges from n=9 to n=80. The graph drawn on the frequency distribution of basic chromosome numbers shows a polymodel curve indicating thereby the evolution of species in many directions.The basic chromosome number may be n=7, from which species with n=9, n=10, n=11 and n=13 might have arisen by aneuploidy. The basic numbers n=16, n=17 and n=18 are secondarily balanced tetraploids by means of euploidy and aneuploidy. The basic numbers n=20, n=21 and n=22 may be secondarily balanced higher polyploids. The basic numbers n=49 and n=80 may be secondarily balanced allopolyploids which might have been evolved by hybridization of any two species followed by polyploidization. Therefore, autopolyploidy as well as allopolyploidy might have played important role in the the origin and evolution of the species of South Indian Capparidaceae.
2 citations
TL;DR: The zoeal and megalopal stage of Macrophthalmus erato were obtained under laboratory conditions and are described and figured and their features are compared with those of known species of the genus.
Abstract: The zoeal and megalopal stage ofMacrophthalmus erato were obtained under laboratory conditions and are described and figured. Five zoeal and one megalopal stages were reared at 25‰; salinity and temperature of 29°C. Their features are compared with those of known species of the genus.
2 citations
TL;DR: In this paper, a study on the unsteady flow of a viscous and incompressible fluid in a channel bounded by two parallel plates for the two cases, (1) when it is rotated impulsively with the constant angular velocity Ω and (2) when the rotating channel is stopped abruptly.
Abstract: A study is made on the unsteady flow of a viscous and incompressible fluid in a channel bounded by two parallel plates for the two cases, (1) when it is rotated impulsively with the constant angular velocity Ω and (2) when the rotating channel is stopped abruptly. In both cases exact solutions of the equations of motion are obtained. It is found that in the first case the steady state conditions are reached in an oscillatory manner, while this phenomenon is not found in the latter case.
DOI•
01 Aug 1988TL;DR: For 2-methyl-4-nitroanisole and 2-halogeno-4,nitro-anisoles, diamagnetic susceptibilities are significantly lower than the expected value, indicating that the 2-substituent in these compounds enhances the resonance interaction of the 1,4-substantives.
Abstract: Evidence for steric enhancement of resonance in some benzene derivatives is obtained from their diamagnetic susceptibilities. Conjugative interaction of substituents in the benzene ring results in a decrease in diamagnetic susceptibility. For 2-methyl-4-nitroanisole and 2-halogeno-4-nitroanisoles the observed diamagnetic susceptibilities are significantly lower than the expected value, indicating that the 2-substituent in these compounds enhances the resonance interaction of the 1,4-substituents. Interestingly, the diamagnetic susceptibility data also show steric inhibition of resonance in 2,6-disubstituted-4-nitroanisoles. 2-Methyl-4-nitrothioanisole seems to exhibit a behaviour similar to that of its oxygen analogue, though the evidence for steric enhancement of resonance in this case is not beyond doubt. 2,6-Dimethyl-4-nitrothioanisole, however, convincingly shows the expected steric inhibition of resonance. The diamagnetic susceptibilities of 3-substituted-4-methoxyacetophenones also furnish further evidence for steric enhancement of resonance.