Ultrastructure and karyology of Tetramyxa parasitica (Plasmodiophoromycetes)

1990 ◽  
Vol 68 (3) ◽  
pp. 594-598 ◽  
Author(s):  
James P. Braselton
Keyword(s):  
Chromosome Number ◽  
Key Words ◽  
Single Unit ◽  
Nuclear Division ◽  
Ruppia Maritima ◽  
Serial Sections ◽  
Unit Membrane ◽  
Haploid Chromosome Number ◽  
Resting Spores ◽  
Host Parasite

Tetramyxa parasitica Goebel was located in galls on shoots of Ruppia maritima L. var. maritima and Zannichellia palustris L. subsp. repens (Boenn.) Schübler & Martens. Ultrastructural features of sporogenic (cystogenous) development included a host–parasite boundary of a single unit membrane, cruciform nuclear division in young plasmodia, synaptomenal complexes in nuclei of transitional plasmodia, and resting spores grouped in fours. Synaptonemal complexes in nuclei were counted through analysis of serial sections. The haploid chromosome number was determined to be 32, which distinguished Tetramyxa from other plasmodiophorid genera. Key words: karyotype, Tetramyxa, Plasmodiophoromycetes.

Ultrastructural karyology of Spongospora subterranea (Plasmodiophoromycetes)

1992 ◽  
Vol 70 (6) ◽  
pp. 1228-1233 ◽  
Author(s):  
James P. Braselton
Keyword(s):  
Electron Microscopy ◽  
Single Unit ◽  
Spongospora Subterranea ◽  
Unit Membrane ◽  
Potato Tubers ◽  
Haploid Chromosome Number ◽  
Synaptonemal Complexes ◽  
Transmission Electron ◽  
Host Parasite ◽  
Section Analysis

Sporogenic (cystogenous) stages of development of Spongospora subterranea (Wallroth) Lagerheim f.sp. subterranea Tomlinson infecting potato tubers were examined with transmission electron microscopy. Volume of nuclei in transitional Plasmodia was 28.2 ± 8.3 μm3. Serial section analysis revealed 37 synaptonemal complexes, hence the haploid chromosome number was considered to be 37. Total length of synaptonemal complexes per nucleus was 74.6 ± 1.4 μm, with individual synaptonemal complexes ranging in length from 1.34 ± 0.07 μm to 3.48 ± 0.17 μm. No polycomplexes were observed in transitional nuclei. Electron-opaque thickenings of lateral elements occurred irregularly. Additional ultrastructural features of sporogenic plasmodia included end-to-end paired centrioles defining the poles of the nuclei and a host–parasite boundary of a single unit membrane. Key words: karyotype, Plasmodiophoromycetes, Spongospora, synaptonemal complex.

The Plasmodiophoromycete parasitic on Heteranthera dubia

1983 ◽  
Vol 61 (1) ◽  
pp. 45-52 ◽  
Author(s):  
James P. Braselton
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Single Unit ◽  
Host Cells ◽  
Synaptonemal Complexes ◽  
Transmission Electron ◽  
Resting Spores ◽  
End To End ◽  
Host Parasite

Light and transmission electron microscopy were used to characterize representative stages of sporogenic plasmodia and resting spores of the plasmodiophorid parasite in roots of Heteranthera dubia (Jacq.) MacM. (water-stargrass). Cruciform nuclear divisions occurred in young plasmodia and noncruciform divisions occurred in more mature, transitional plasmodia. Prophase nuclei in transitional plasmodia contained synaptonemal complexes; noncruciform divisions were interpreted, therefore, as meiosis. Host–parasite interfaces were single unit membranes. Centrioles were paired end-to-end in plasmodia, but unpaired, single centrioles were in resting spores. Resting spores also contained crystalline bodies. Sporosori were disklike, consisted predominantly of single layers of resting spores, and were located at the periphery of host cells. Membranosorus heterantherae Ostenfeld and Peterson was considered the appropriate genus–species for the parasite, not Sorodiscus heterantherae Wernham.

scholarly journals A long reads-based de-novo assembly of the genome of the Arlee homozygous line reveals chromosomal rearrangements in rainbow trout

2021 ◽  
Author(s):  
Guangtu Gao ◽  
Susana Magadan ◽  
Geoffrey C Waldbieser ◽  
Ramey C Youngblood ◽  
Paul A Wheeler ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Chromosome Number ◽  
Genome Assembly ◽  
De Novo Assembly ◽  
De Novo ◽  
Sequence Data ◽  
Structural Variations ◽  
High Coverage ◽  
Haploid Chromosome Number ◽  
Long Reads

Abstract Currently, there is still a need to improve the contiguity of the rainbow trout reference genome and to use multiple genetic backgrounds that will represent the genetic diversity of this species. The Arlee doubled haploid line was originated from a domesticated hatchery strain that was originally collected from the northern California coast. The Canu pipeline was used to generate the Arlee line genome de-novo assembly from high coverage PacBio long-reads sequence data. The assembly was further improved with Bionano optical maps and Hi-C proximity ligation sequence data to generate 32 major scaffolds corresponding to the karyotype of the Arlee line (2 N = 64). It is composed of 938 scaffolds with N50 of 39.16 Mb and a total length of 2.33 Gb, of which ∼95% was in 32 chromosome sequences with only 438 gaps between contigs and scaffolds. In rainbow trout the haploid chromosome number can vary from 29 to 32. In the Arlee karyotype the haploid chromosome number is 32 because chromosomes Omy04, 14 and 25 are divided into six acrocentric chromosomes. Additional structural variations that were identified in the Arlee genome included the major inversions on chromosomes Omy05 and Omy20 and additional 15 smaller inversions that will require further validation. This is also the first rainbow trout genome assembly that includes a scaffold with the sex-determination gene (sdY) in the chromosome Y sequence. The utility of this genome assembly is demonstrated through the improved annotation of the duplicated genome loci that harbor the IGH genes on chromosomes Omy12 and Omy13.

scholarly journals THE CELL ENVELOPES OF TWO EXTREMELY HALOPHILIC BACTERIA

1963 ◽  
Vol 18 (3) ◽  
pp. 681-689 ◽  
Author(s):  
A. D. Brown ◽  
C. D. Shorey
Keyword(s):  
Single Unit ◽  
Cell Envelope ◽  
Halophilic Bacteria ◽  
Layered Compound ◽  
Halobacterium Halobium ◽  
Chemical Analyses ◽  
Unit Membrane ◽  
Thin Sections ◽  
Whole Cells ◽  
Cell Envelopes

The cell envelope of Halobacterium halobium was seen in thin sections of permanganate-fixed cells to consist of one membrane. This membrane appeared mostly as a unit membrane but in a few preparations it resembled a 5-layered compound membrane. The cell envelope of Halobacterium salinarium at high resolution was always seen as a 5-layered structure different in appearance from the apparent compound membrane of H. halobium. The "envelopes" which were isolated in 12.5 per cent NaCl from each organism were indistinguishable from each other in the electron microscope and comprised, in each case, a single unit membrane with an over-all thickness of about 110 A. Some chemical analyses were made of isolated membranes after freeing them from salt by precipitating and washing with trichloroacetic acid. Such precipitated membranes consisted predominantly of protein, with little carbohydrate and no peptido-aminopolysaccharide (mucopeptide). Sectioned whole cells of H. halobium contained intracellular electron-opaque structures of unknown function.

Helminths of the Alimentary Tract from a Stranded Herd of the Atlantic White-Sided Dolphin, Lagenorhynchus acutus

1978 ◽  
Vol 35 (10) ◽  
pp. 1356-1359 ◽  
Author(s):  
M. Beverley-Burton
Keyword(s):  
Key Words ◽  
Alimentary Tract ◽  
New Host ◽  
Lagenorhynchus Acutus ◽  
Host Parasite ◽  
Biological Tags

Six species of helminths were collected from the gut of 37 Lagenorhynchus acutus. The following are new host–parasite records: Pholeter gastrophilus, Oschmarinella laevicaecum, Tetrabothrius forsteri, Anisakis sp., and Bolbosoma sp. Stenurus globicephalae was also found. Prevalence for O. laevicaecum was 49% and for T. forsteri 78%. Key words: Atlantic dolphins, digenea trematodes, cestodes, nematodes, acanthocephala, biological tags

scholarly journals Chromosomal and DNA barcode analysis of the Melitaea ala Staudinger, 1881 species complex (Lepidoptera, Nymphalidae)

2021 ◽  
Vol 15 (2) ◽  
pp. 199-216
Author(s):  
Vladimir A. Lukhtanov ◽  
Anastasia V. Gagarina ◽  
Elena A. Pazhenkova
Keyword(s):  
Chromosome Number ◽  
Central Asia ◽  
Species Complex ◽  
Dna Barcode ◽  
Monophyletic Group ◽  
Geographic Proximity ◽  
Haploid Chromosome Number ◽  
East Central ◽  
North East ◽  
Peter The Great

The species of the Melitaea ala Staudinger, 1881 complex are distributed in Central Asia. Here we show that this complex is a monophyletic group including the species, M. ala, M. kotshubeji Sheljuzhko, 1929 and M. enarea Fruhstorfer, 1917. The haploid chromosome number n=29 is found in M. ala and M. kotshubeji and is, most likely, a symplesiomorphy of the M. ala complex. We show that M. ala consists of four subspecies: M. ala zaisana Lukhtanov, 1999 (=M. ala irtyshica Lukhtanov, 1999, syn. nov.) (South Altai, Zaisan Lake valley), M. ala ala (Dzhungarian Alatau), M. ala bicolor Seitz, 1908 (North, East, Central and West Tian-Shan) and M. ala determinata Bryk, 1940 (described from “Fu-Shu-Shi”, China). We demonstrate that M. kotshubeji kotshubeji (Peter the Great Mts in Tajikistan) and M. kotshubeji bundeli Kolesnichenko, 1999 (Alai Mts in Tajikistan and Kyrgyzstan) are distinct taxa despite their geographic proximity in East Tajikistan. Melitaea enarea is widely distributed in the southern part of Central Asia and is sympatric with M. kotshubeji.

scholarly journals A taxonomic revision of the genus Cleome L. (Capparaceae) in Bangladesh

1970 ◽  
Vol 14 (1) ◽  
pp. 25-36
Author(s):  
Hosne Ara ◽  
Bushra Khan ◽  
Md. Mansur-ul-Kadir Mia
Keyword(s):  
Chromosome Number ◽  
Key Words ◽  
Geographical Distribution ◽  
Taxonomic Revision ◽  
Economic Importance ◽  
Plant Taxon

The available record of the genus Cleome L. for Bangladesh has been updated in this paper and includes C. diffusa, C. gynandra, C. hassleriana, C. rutidosperma and C. viscosa. The updating has been done in case of nomenclature with important synonyms, local names, description of the taxa along with illustrations, flowering and fruiting times, ecological notes, specimens examined and their geographical distribution. For identification of the species, a dichotomous bracketed key has been added in this paper. Information on chromosome number and economic importance have also been provided where available. Key words: Cleome, Taxonomic revision, Capparaceae, Bangladesh DOI: 10.3329/bjpt.v14i1.520 Bangladesh J. Plant Taxon. 14(1): 25-36, 2007 (June)

Observations on the Fine Structure and Development of the Spindle at Mitosis and Meiosis in a Marine Centric Diatom (Lithodesmium Undulatum)

1970 ◽  
Vol 7 (2) ◽  
pp. 407-443
Author(s):  
IRENE MANTON ◽  
K. KOWALLIK ◽  
H. A. VON STOSCH
Keyword(s):  
Centric Diatom ◽  
Serial Sections ◽  
Late Prophase ◽  
Haploid Chromosome Number ◽  
Male Gametogenesis ◽  
Common Time ◽  
Precursor Material ◽  
Mitosis And Meiosis ◽  
Meiosis I ◽  
Unusual Shape

The second meiotic division is shown to be of critical importance for interpretation of structures and events already seen at other divisions. The development of flagellar bases at interkinesis is demonstrated in relation to precursor material seen to accumulate near each pole at meiosis I. The name ‘paracentrosome’ is suggested for this material, which is used up in forming the flagellar bases and spindle precursor. The spindle at late prophase, metaphase and telophase II is shown to resemble those of other divisions except that it is consistently smaller; this fact is numerically demonstrated from serial sections of metaphase II cells. The greatly reduced size and unusual shape of the polar plates present in addition to flagellar bases at metaphase II suggest that these are in a sense equivalent structures with a mutually competitive relation to the paracentrosome. Preliminary observations with the light microscope on the relatively large nuclei of oogonia during meiosis I have shown that the haploid chromosome number is not less than 19 nor more than 23 and that chromatid separation in relation to the kinetochores at anaphase I is normal; the bearing of these findings on interpretation of the spindle is discussed. Comparisons with other organisms are carried out in a preliminary way and the investigation ends with a résumé of the more important externally visible events in male gametogenesis adjusted to a common time scale in the course of one day.

scholarly journals Unprecedented reorganization of holocentric chromosomes provides insights into the enigma of lepidopteran chromosome evolution

2019 ◽  
Vol 5 (6) ◽  
pp. eaau3648 ◽  
Author(s):  
Jason Hill ◽  
Pasi Rastas ◽  
Emily A. Hornett ◽  
Ramprasad Neethiraj ◽  
Nathan Clark ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Chromosome Evolution ◽  
Chromosome Structure ◽  
Holocentric Chromosomes ◽  
Chromosome Counts ◽  
Pieris Napi ◽  
Haploid Chromosome Number ◽  
Genome Wide ◽  
The Face ◽  
Chromosome Level

Chromosome evolution presents an enigma in the mega-diverse Lepidoptera. Most species exhibit constrained chromosome evolution with nearly identical haploid chromosome counts and chromosome-level gene collinearity among species more than 140 million years divergent. However, a few species possess radically inflated chromosomal counts due to extensive fission and fusion events. To address this enigma of constraint in the face of an exceptional ability to change, we investigated an unprecedented reorganization of the standard lepidopteran chromosome structure in the green-veined white butterfly (Pieris napi). We find that gene content in P. napi has been extensively rearranged in large collinear blocks, which until now have been masked by a haploid chromosome number close to the lepidopteran average. We observe that ancient chromosome ends have been maintained and collinear blocks are enriched for functionally related genes suggesting both a mechanism and a possible role for selection in determining the boundaries of these genome-wide rearrangements.

OBSERVATIONS ON PEROXISOMES IN BROWN ADIPOSE TISSUE OF THE RAT

1971 ◽  
Vol 19 (11) ◽  
pp. 670-675 ◽  
Author(s):  
IRÉNE AHLABO ◽  
TUDOR BARNARD
Keyword(s):  
Hydrogen Peroxide ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Single Unit ◽  
Brown Fat ◽  
Unit Membrane ◽  
Peroxisomal Enzyme ◽  
Brown Adipose ◽  
Homogeneous Matrix ◽  
Physiologic Activity

During cytochemical studies of brown adipose tissue from rat, cytoplasmic organelles that apparently show peroxidative activity have been observed. The majority of the organelles have a diameter of 0.1-0.8 µ and a finely granular homogeneous matrix and are delimited by a single unit membrane. No sign of a "crystalloid" was seen. In order to demonstrate the peroxidative activity of the peroxisomal enzyme catalase in the organelles, brown adipose tissue was incubated in a medium containing 3,3'-diaminobenzidine tetrahydrochloride, after prefixation in 3% glutaraldehyde. The activity was blocked by 3-amino-l,2,4-triazole (an inhibitor of catalase) but not by KCN. Omission of exogenous hydrogen peroxide did not inhibit the reaction in the organelles. It is concluded that rat brown adipose tissue contains peroxisomes and, since the abundance of these organelles varies according to the physiologic activity of the tissue, peroxisomes may have a role in the thermogenic metabolism of brown fat.

Sign in / Sign up

Export Citation Format

Share Document