The cytology and development of Preussia flanaganii sp. nov.

1970 ◽  
Vol 48 (1) ◽  
pp. 163-166 ◽  
Author(s):  
Brendan V. Boylan
Keyword(s):  
Life Cycle ◽  
Chromosome Number ◽  
Hyphal Fusion ◽  
Nuclear Cycle ◽  
Fusion Site

The life cycle of Preussia flanaganii Boylan sp. nov. is demonstrated. The ascocarp develops as a result of hyphal fusion and the subsequent proliferation of pseudoparenchyma at the fusion site. The ascocarp is uniloculate or multiloculate and non-ostiolate. The fungus has no known asexual phase and is homothallic. The nuclear cycle in the asci follows a pattern similar to that found in other Euascomycetes. The chromosome number is about 14.

NUCLEAR PHENOMENA IN THE LIFE CYCLE OF GANODERMA LUCIDUM (LEYSS. EX FR.) KARST.

1959 ◽  
Vol 37 (1) ◽  
pp. 59-64 ◽  
Author(s):  
Anjali Sarkar
Keyword(s):  
Life Cycle ◽  
Chromosome Number ◽  
Ganoderma Lucidum ◽  
West Bengal ◽  
The Other ◽  
Multinucleate Cells ◽  
Nuclear Behavior

Nuclear behavior in the life cycle of Ganoderma lucidum (Leyss. ex Fr.) Karst., a common polypore in West Bengal, India, has been studied. Each young basidium is binucleate and the nuclei soon fuse to form a syncaryon which undergoes three successive divisions, of which the first is reductional, to produce eight daughter nuclei. Four nuclei pass into the four spores, one into each, and the other four, remaining within the basidium, finally degenerate. Thus at first each basidiospore contains one nucleus which may or may not divide further. On germination, the spores give rise to primary mycelia with uninucleate or multinucleate cells. Secondary mycelia, formed by the union of two compatible primary mycelia, have nodose-septate hyphae in which most of the cells are dikaryotic although cells with more than two nuclei are not uncommon.The chromosome number, counted from metaphasic plates, has been found to be 10 = 2n.

A CYTOLOGICAL STUDY OF ASCOCYBE

1961 ◽  
Vol 39 (7) ◽  
pp. 1605-1607 ◽  
Author(s):  
Charles M. Wilson
Keyword(s):  
Life Cycle ◽  
Chromosome Number ◽  
Cytological Study ◽  
Nuclear Behavior

The nuclear behavior in the life cycle of Ascocybe grovesii is described. The chromosome number is given as six from counts made of chromosomes in the meiotic divisions in the asci. The ascophores are described as diploid, and as a consequence there is no fusion of nuclei in the asci.

Ultrastructural aspects of sporogenesis in the apogamous fern Dryopteris borreri

1983 ◽  
Vol 63 (1) ◽  
pp. 125-134
Author(s):  
E. Sheffield ◽  
S. Laird ◽  
P.R. Bell
Keyword(s):  
Life Cycle ◽  
Cell Division ◽  
Chromosome Number ◽  
Plant Cell ◽  
Major Part ◽  
The Novel ◽  
Wall Ingrowths ◽  
Plant Cell Division ◽  
Discrete Band ◽  
Meiosis I

The events that accompany sporogenesis in the apogamous fern Dryopteris borreri parallel those seen in sexually reproducing ferns. Organelles dedifferentiate and redifferentiate, and form a discrete band across the equator of dyads; nuclear vacuoles and lipid spherosomes appear during prophase, and the major part of the ribosome population is removed and subsequently replaced during meiosis. Similar events have been found to occur during sporogenesis in mosses, gymnosperms and angiosperms, and therefore characteristic of the meiotic transition from sporophyte to gametophyte, even in the absence of a transition from diplophase to haplophase. The novel aspects of meiosis in D. borreri are largely those connected with the restitution event that precedes meiosis I and serves to maintain the sporophytic chromosome number throughout the life cycle of this fern. Pre-meiotic cells are regularly found to be cleaved by annular wall ingrowths, which traverse the cytoplasm but not the nuclei. The significance of these ingrowths in relation to theories concerning apogamy and plant cell division are discussed.

Nuclear DNA content and chromosome numbers throughout the life cycle of the Colonia strain of the myxomycete, Physarum polycephalum

1977 ◽  
Vol 24 (1) ◽  
pp. 95-108
Author(s):  
J. Mohberg
Keyword(s):  
Lactic Acid ◽  
Life Cycle ◽  
Chromosome Number ◽  
Dna Content ◽  
Physarum Polycephalum ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
S Phase ◽  
Dna Analyses

Nuclear DNA content and ploidy have been determined at different stages of the life cycle of the Colonia strain of the myxomycete Physarum polycephalum. Analyses at the plasmodial stage showed that (a) Burton and Fuelgen DNA analyses agreed within 15% with strains which ranged from 0-6 to 3-6 pg of DNA per nucleus; (b) S-phase in Colonia is during the early part of interphase as in the Wisconsin strain; (c) in heterothallic and heterothallic × Colonia crossed strains there are 1-0-1-2 pg of DNA and 70 chromosomes per nucleus and in Colonia 0-6 pg of DNA and 40 chromosomes. Germinating spores of all strains contained one population of cells with about 0-5 pg of DNA and 40 chromosomes and another of larger cells with up to 2-5 pg of DNA and 200 chromosomes. The polyploid nuclei comprised 2–20% of the total in heterothallic strains, 2–65% in heterothallic × Colonia crosses and 25–75% in Colonia. A method was devised for making chromosome spreads of amoebae grown on bacterial lawns. Cells were first exposed to dilute formaldehyde at 26 degrees C for 30 min, then spread on slides with hot lactic acid and strained. Such spreads of CLd (Colonia) and RSD4 (heterothallic) amoebae both contained about 40 chromosomes. The data are consistent with the view that Colonia is haploid throughout its life cycle and that chromosome number is neither halved during sporulation nor doubled during plasmoidal formation. However, the possibility exists that an alternance of ploidy occurs by way of the few diploid nuclei present in the plasmodium.

Studies on North Indian Volvocales. VI. On the life cycle and cytology of a new member of Phacotaceae, Dysmorphococcus sarmaii sp. nov.

1981 ◽  
Vol 59 (5) ◽  
pp. 726-734 ◽  
Author(s):  
R. Shyam
Keyword(s):  
New Species ◽  
Life Cycle ◽  
Chromosome Number ◽  
Sexual Reproduction ◽  
Asexual Reproduction ◽  
Morphological Variability ◽  
The Other ◽  
Laboratory Conditions ◽  
Contractile Vacuoles ◽  
A New Species

This paper deals with the morphology, reproduction, and cytology of a new species of Dysmorphococcus, viz., Dysmorphococcus sarmaii sp. nov. (Phacotaceae, Volvocales) from India. The lorica of this flagellate displays a remarkable morphological variability in nature as well as in culture under laboratory conditions. The alga is characterised by an anteriorly bilobed pentagonal lorica ornamentated with polygonal pores, a massive globose chloroplast that lacks a pyrenoid and almost completely occupys the protoplast, a prominent red stigma, two contractile vacuoles located anteriorly near the insertion of the flagella, and flagella that are equal to or a little longer than the length of the lorica. The pentagonal lorica of the present taxon differs remarkably from the broadly ovoid to globose lorica of D. variabilis Takeda, D. coccifer Korschikoff, and D. globosus Bold and Starr. The lorica of D. sarmaii is somewhat comparable in shape to D. punctatus Fott because of its bilobed anterior but differs from the latter in its ornamentation. The massive globose chloroplast lacking a pyrenoid in the present alga differs remarkably from the other species of this genus where the chloroplast possesses one or several pyrenoids. In addition, asexual reproduction, which is accomplished by division of the protoplast within the lorica, results in the production of 8–16 zoospores as compared with the earlier record of 2 and 4 zoospores in this genus. The alga is heterothallic and sexual reproduction, which was not known for the earlier described species of the genus Dysmorphococcus, takes place by isogametes produced 16–32(–64) per cell. The chromosome number recorded for D. sarmaii is n = 10.

scholarly journals The nuclear cycle in bacteria

1949 ◽  
Vol 47 (2) ◽  
pp. 182-187 ◽  
Author(s):  
K. A. Bisset
Keyword(s):  
Life Cycle ◽  
Central Body ◽  
Spore Formation ◽  
Lag Phase ◽  
Vegetative Phase ◽  
Reduction Processes ◽  
Nuclear Cycle

1. Strains ofBact. coliand related bacteria possess a life cycle resembling that of Myxobacteria. The vesicular, resting nucleus is contained in a microcyst, which is formed by a process suggestive of sexual conjugation.2. The microcyst germinates by the transformation of the resting nucleus into the chromosome-like bodies typical of active, vegetative cultures. These may be analogous to the chromosome complexes of yeasts. The period of germination of microcysts corresponds to the lag phase of cultures.3. The nucleus remains permanently in the mitotic condition during the active, vegetative phase of growth, and reproduces by an asexual and a sexual method.4. Older cultures may be transformed directly into microcysts or may first adopt a secondary, vegetative phase, in which the nucleus is in the form of a single, central body.5. Microcyst formation differs from spore formation in that it lacks the obvious reduction processes associated with spore formation, upon which a few original observations are included.

scholarly journals Extensive karyotype variability of African fish genus Nothobranchius (Cyprinodontiformes)

2018 ◽  
Vol 12 (3) ◽  
pp. 387-402 ◽  
Author(s):  
Eugene Krysanov ◽  
Tatiana Demidova
Keyword(s):  
Life Cycle ◽  
Chromosome Number ◽  
Diploid Chromosome Number ◽  
East African ◽  
Multiple Sex Chromosomes ◽  
Karyotype Variability ◽  
Karyotypic Formula ◽  
Unstable Environment ◽  
First Time ◽  
Species Proportion

Karyotypes of 65 species of the genus Nothobranchius Peters, 1868 were reviewed and of those 35 examined first time. The results of present study have shown that fishes of the genus Nothobranchius possessed highly diverse karyotypes. The diploid chromosome number (2n) ranged from 16 to 50. The most frequent 2n was 2n = 36 (in 35 species) while the second one 2n = 38 (in 13 species). Proportion of biarmed chromosomes varied from 0 to 95% between species. Diploid chromosome number variability apparently exists as a result of chromosomal fusions or fissions and extensive karyotypic formula alterations promoting by inversions. Multiple sex chromosomes of system X1X1X2X2/X1X2Y type were found only in karyotypes of 5 species. The extensive karyotype variability, unusual for teleosts, of genus Nothobranchius can be likely associated with the characteristics of its life cycle and inhabiting under unstable environment of East African savannah temporal pools.

scholarly journals The Aseptic Culture of Arabidopsis Thaliana (l.) Heynh.

1957 ◽  
Vol 10 (3) ◽  
pp. 243 ◽  
Author(s):  
J Langridge
Keyword(s):  
Arabidopsis Thaliana ◽  
Life Cycle ◽  
Chromosome Number ◽  
Rapid Growth ◽  
Optimal Growth ◽  
Life Cycles ◽  
High Fertility ◽  
Aseptic Culture ◽  
Other Substances ◽  
Aseptic Conditions

Arabidopsis thaliana (L.) Heynh. is a small, rapidly growing crucifer with a 28-day life cycle, a low chromosome number (n=5), and a high fertility (152�1l seeds under aseptic conditions). The small size and rapid growth of the plants enable them to be grown throughout their life cycles on sterile, nutrient agar in ordinary' test tubes. Alternatively, up to 50 plants may be grown on silica gel in crystallizing dishes. For optimal growth the trace element cations should be chelated and light should be excluded from the roots. When supplied with sucrose the plants absorb only the glucose portion. During growth the plants excrete small quantities of vitamins and other substances into the medium but not in amounts likely to prevent the detection of growth mutants through cross-feeding.

Ultrastructural analysis of “Sensory” surface nerve endings and “putative” neurotransmitter sites in Schistosoma mansoni Miracidia

1989 ◽  
Vol 47 ◽  
pp. 962-963
Author(s):  
Betty Ruth Jones ◽  
Steve Chi-Tang Pan
Keyword(s):  
Nervous System ◽  
Life Cycle ◽  
Schistosoma Mansoni ◽  
Snail Host ◽  
Complex Life Cycle ◽  
Rational Approach ◽  
Effective Control ◽  
The Social ◽  
Social And Economic Development ◽  
Basic Biology

INTRODUCTION: Schistosomiasis has been described as “one of the most devastating diseases of mankind, second only to malaria in its deleterious effects on the social and economic development of populations in many warm areas of the world.” The disease is worldwide and is probably spreading faster and becoming more intense than the overall research efforts designed to provide the basis for countering it. Moreover, there are indications that the development of water resources and the demands for increasing cultivation and food in developing countries may prevent adequate control of the disease and thus the number of infections are increasing.Our knowledge of the basic biology of the parasites causing the disease is far from adequate. Such knowledge is essential if we are to develop a rational approach to the effective control of human schistosomiasis. The miracidium is the first infective stage in the complex life cycle of schistosomes. The future of the entire life cycle depends on the capacity and ability of this organism to locate and enter a suitable snail host for further development, Little is known about the nervous system of the miracidium of Schistosoma mansoni and of other trematodes. Studies indicate that miracidia contain a well developed and complex nervous system that may aid the larvae in locating and entering a susceptible snail host (Wilson, 1970; Brooker, 1972; Chernin, 1974; Pan, 1980; Mehlhorn, 1988; and Jones, 1987-1988).

A freeze-fracture-etched study of the physarum polycephalum plasma membrane during early formation of the macroplasmodial stage

1993 ◽  
Vol 51 ◽  
pp. 346-347
Author(s):  
Randolph W. Taylor ◽  
Henrie Treadwell
Keyword(s):  
Plasma Membrane ◽  
Life Cycle ◽  
Growth Phase ◽  
Filter Paper ◽  
Physarum Polycephalum ◽  
Freeze Fracture ◽  
Petri Dish ◽  
Wire Screen ◽  
Wide Mouth ◽  
Sterile Filter

The plasma membrane of the Slime Mold, Physarum polycephalum, process unique morphological distinctions at different stages of the life cycle. Investigations of the plasma membrane of P. polycephalum, particularly, the arrangements of the intramembranous particles has provided useful information concerning possible changes occurring in higher organisms. In this report Freeze-fracture-etched techniques were used to investigate 3 hours post-fusion of the macroplasmodia stage of the P. polycephalum plasma membrane.Microplasmodia of Physarum polycephalum (M3C), axenically maintained, were collected in mid-expotential growth phase by centrifugation. Aliquots of microplasmodia were spread in 3 cm circles with a wide mouth pipette onto sterile filter paper which was supported on a wire screen contained in a petri dish. The cells were starved for 2 hrs at 24°C. After starvation, the cells were feed semidefined medium supplemented with hemin and incubated at 24°C. Three hours after incubation, samples were collected randomly from the petri plates, placed in plancettes and frozen with a propane-nitrogen jet freezer.

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