A contribution towards elucidating the life history of Palmaria palmate (=Rhodymenia palmata)

1976 ◽  
Vol 54 (24) ◽  
pp. 2903-2906 ◽  
Author(s):  
J. P. van der Meer
Keyword(s):  
Life History ◽  
Chromosome Number ◽  
Atlantic Coast ◽  
Palmaria Palmata ◽  
Haploid Chromosome Number ◽  
History Of

Palmaria palmata from a region of the Atlantic coast of Canada has been examined cytologically. Plants bearing tetrasporangia were found to be diploid with meiosis occurring in the tetrasporangia. Spermatangial plants and sporelings growing from tetraspores were haploid. The haploid chromosome number appears to be 22–23.

The life history of Halosaccion ramentaceum

1981 ◽  
Vol 59 (4) ◽  
pp. 433-436 ◽  
Author(s):  
John P. van der Meer
Keyword(s):  
Life History ◽  
Chromosome Number ◽  
Sexual Maturity ◽  
Mutant Phenotype ◽  
Sexual Cycle ◽  
Palmaria Palmata ◽  
Male And Female ◽  
Haploid Male ◽  
History Of ◽  
Mendelian Transmission

The complete life history of Halosaccion ramentaceum has been determined. It is very similar to that of Palmaria palmata, consisting of haploid male and female gametophytes alternating with a diploid tetrasporophyte. As for P. palmata, there is no carposporophyte. Male and female gametophytes attain sexual maturity almost a generation apart. Whereas male plants require approximately 1 year's growth before producing spermatia, female gametophytes are microscopic and reach sexual maturity only a few days after tetraspore germination. The diploid tetrasporophyte initiates its development on the female, but almost immediately forms an independent holdfast on the substratum beside the female. The first diploid fronds arise from that holdfast after it is well established.The existence of a complete sexual cycle was proven by demonstrating: fertilization of trichogynes by spermatia; meiosis in tetrasporangia, with a chromosome number of n = ~24 in gametophytes and 2n = ~48 in tetrasporophytes; and by documenting the Mendelian transmission of a mutant phenotype from the male parent to the F1 gametophytes.

Chromosome cycle in the gregarine Stylocephalus mesomorphi Dev.

Parasitology ◽  
1966 ◽  
Vol 56 (2) ◽  
pp. 199-208
Author(s):  
R. N. Desai
Keyword(s):  
Life History ◽  
Chromosome Number ◽  
The Other ◽  
Medium Size ◽  
Mitotic Chromosomes ◽  
Zygote Nucleus ◽  
Entire Life ◽  
Science College ◽  
History Of ◽  
Zoology Department

The gregarine Stylocephalus mesomorphi has a diploid chromosome number of 8. The diploid stage is represented only by the zygote nucleus before the metagamic divisions start. The other stages in the entire life history of this gregarine are haploid.The mitotic chromosomes are four in number, one being the longest, two of medium size and the fourth the smallest.I am grateful to Professor J. C. Uttangi, Head of the Zoology Department, Karnatak Science College, Dharwar, for the encouragement he gave me throughout this work. I am also greatly indebted to my colleague Dr M. J. Devadhar, for having given me many valuable suggestions.

Researches on the intestinal protozoa of monkeys and man

Parasitology ◽  
1940 ◽  
Vol 32 (4) ◽  
pp. 417-461 ◽  
Author(s):  
Clifford Dobell
Keyword(s):  
Life History ◽  
Chromosome Number ◽  
Nuclear Structure ◽  
Oral Infection ◽  
Binary Fission ◽  
Intestinal Protozoa ◽  
Human Faeces ◽  
Dientamoeba Fragilis ◽  
History Of ◽  
Nematode Worm

1. The morphology and life-history of Dientamoeba fragilis, as observable in cultures, are described and illustrated, and the stages correlated with those commonly found in human faeces.2. The nuclear structure especially is reinterpreted, and nuclear and cytoplasmic division are described in detail.3. It is shown that the “normal” binucleate condition of this “amoeba” represents an arrested telophase stage of mitosis—the “granules” in the nuclei being really chromosomes (constant in number), and the strand connecting the nuclei being a persistent centrodesmus. The chromosome number is probably 6 (certainly not 4).4. Binary fission is the only method of reproduction hitherto observed: no cysts or other stages in the life-history have been discovered.5. Attempts to transmit D. fragilis to a man and 2 macaques (M. rhesus and M. sinicus) by administration of trophic amoebae per os—and in the case of M. rhesus inoculation per anum—were unsuccessful. It was also found impossible to infect chickens permanently by injection per anum (though one chick acquired an infection lasting for a week).6. Consideration of its cytology and development leads to the conclusion that D. fragilis is not a true amoeba but an aberrant flagellate closely related to Histomonas. No flagellate stages, however, have yet been discovered.7. Some consequences of this conclusion are briefly discussed, and hopeful directions for further inquiries are indicated.8. On analogy with Histomonas, it is suggested that D. fragilis may be conveyed from man to man not by direct oral infection with trophic forms but in the ova of a nematode worm—possibly Trichuris (or Ascaris?).

The life history of Palmaria palmata in culture. A new type for the Rhodophyta

1980 ◽  
Vol 58 (11) ◽  
pp. 1250-1256 ◽  
Author(s):  
John P. van derMeer ◽  
Edna R. Todd
Keyword(s):  
Life History ◽  
Vegetative Growth ◽  
Palmaria Palmata ◽  
Recessive Mutation ◽  
Male And Female ◽  
Carpogonial Branch ◽  
History Of ◽  
New Type ◽  
Sexually Mature ◽  
Older Males

The life history of Palmaria palmata has been completed in culture. Tetraspores from diploid plants gave rise to male and female haploid plants which differed morphologically. Female plants were extremely small and became sexually mature only days after tetraspore release. Trichogynes were observed on plants only 4 days old, and remained conspicuous for several weeks. As the females aged, trichogynes declined in number and they could not be detected on plants 5 months old. In contrast, male plants required several (9–12) months of vegetative growth before they formed spermatia. As a consequence, females had to be fertilized by older males from preceding gametangial generations.The diploid tetrasporangial plants developed directly on fertilized females. As they enlarged, they completely overgrew the small females and formed their own holdfast attachments to the substrate. A recessive mutation resulting in green frond colour was used in crosses designed to yield red diploid tissue on green females after fertilization, thereby greatly facilitating observations on the development of the tetrasporangial phase.Preliminary observations indicate that the carpogonium is a single cell. There appears to be no carpogonial branch or auxilliary cell. The tetrasporangial phase develops from the zygote by simple mitotic divisions, suggesting that the life history is best interpreted as lacking a carposporophyte.

scholarly journals Review and consideration on habitat use, distribution and life history of Lycengraulis grossidens (Agassiz, 1829) (Actinopterygii, Clupeiformes, Engraulididae)

2013 ◽  
Vol 13 (3) ◽  
pp. 121-130 ◽  
Author(s):  
Ana Cecilia Giacometti Mai ◽  
João Paes Vieira
Keyword(s):  
Life History ◽  
Habitat Use ◽  
Current Knowledge ◽  
Atlantic Coast ◽  
Local Population ◽  
High Plasticity ◽  
Southwest Atlantic ◽  
Coastal Fish ◽  
History Of ◽  
Shrimp Fisheries

In this paper, we present a summary of the current knowledge of Lycengraulis grossidens, a widely distributed coastal fish that occurs from Belize to Argentina. This species is abundant in estuaries along the Southwest Atlantic Coast and is important for recreational fishing, and as bycatch of shrimp fisheries. We compiled data available on taxonomy, phylogeny, ecology, fisheries and organized conceptually the life cycle of the species according to modern estuarine-use classification. Our review showed that along its geographic distribution and inside some particular environments (i.e., estuaries and costal lagoons) the species have been classified in a variety of ways in order to describe the remarkable complexity of habitat use that varies from freshwater resident, anadromous, marine migrant, estuarine resident, marine stragglers, catadromous to semi-catadromous. We conclude that L. grossidens is able to reproduce either in freshwater or estuarine water and postulate that it has a high plasticity in habitat use and life history, with migratory and resident contingents in the same local population. There seems to be a latitudinal change in migratory behavior of this species along the South America Coast, prevailing anadromous or semi-anadromous pattern at higher latitudes and marine migrants at the tropical northeast coast of Brazil.

Experimental life history of Echinostoma cinetorchis

1990 ◽  
Vol 28 (1) ◽  
pp. 39 ◽  
Author(s):  
S H Lee ◽  
J Y Chai ◽  
S T Hong ◽  
W M Sohn
Keyword(s):  
Life History ◽  
History Of
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