NUCLEAR PHENOMENA IN THE BASIDIUM OF CERATOBASIDIUM PRATICOLUM (KOTILA) OLIVE

1961 ◽  
Vol 39 (3) ◽  
pp. 717-725 ◽  
Author(s):  
H. K. Saksena
Keyword(s):  
Chromosome Number ◽  
Meiotic Division ◽  
Germ Tube ◽  
Diploid Nucleus ◽  
Haploid Chromosome Number ◽  
Spindle Axis ◽  
Further Development

The nuclear phenomena in the basidium of Ceratobasidium praticolum (Pellicularia praticola), studied by the Giemsa technique, are described and illustrated with photographs. The cells of the vegetative hyphae are multinucleate and those of the hymenia binucleate. Before fusion the two nuclei in the young basidium become closely adjacent, and their chromosomes are differentiated as elongated threads in two distinct groups. After the association of the karyolymph of the two nuclei, the chromosomes come into contact and pair. The diploid nucleus then undergoes meiosis. The haploid chromosome number is about six, with six bivalents present at the first meiotic (disjunctional) division. Apparent chromatid bridges were observed at anaphase I. The second meiotic division is equational. The spindle axis during both these divisions may be longitudinal, transverse, or oblique. The mature basidium has four nuclei which migrate through sterigmata into the basidiospores. Most of the basidiospores are uninucleate when young, but become binucleate at maturity. The basidiospore germinates by repetition or directly by a germ tube. In either case coenocytic growth is produced which, upon further development, is divided into multinucleate hyphal cells by the formation of cross septa.

Changes in DNA content and chromosome number during spermatogenesis in the gall midge Monarthropalpus buxi (Cecidomyiidae, Diptera)

Genome ◽  
1992 ◽  
Vol 35 (2) ◽  
pp. 244-250 ◽  
Author(s):  
B. Jazdowska-Zagrodzinska ◽  
R. Dallai ◽  
C. A. Redi
Keyword(s):  
Chromosome Number ◽  
Key Words ◽  
Meiotic Division ◽  
Dna Content ◽  
Germ Line ◽  
Gall Midge ◽  
Key Words Dna ◽  
Further Development

In this paper we analyze the course of spermatogenesis in Monarthropalpus buxi. The first meiotic division occurs without any chromosomes pairing. As a result one spermatocyte II appears from which two sperms originate, and one residual cell, which does not undergo any further division. We found variations in chromosome number and DNA content between germ line cells of different individuals. Such variations were observed in the spermatocytes I and II, and in the sperms. In contrast, the residual cells, which did not take part in further development, always had the same DNA content and constantly inherited 20 chromosomes: 4 constituting one haploid set of the somatic type (S chromosomes) and 16 of the germ line limited type (E chromosomes).Key words: DNA content, chromosome number, Cecidomyiidae, germ line, spermatogenesis.

Nuclear behavior and clarification of the spore stages of Uromyces koae

1981 ◽  
Vol 59 (5) ◽  
pp. 939-946 ◽  
Author(s):  
Donald E. Gardner
Keyword(s):  
Life Cycle ◽  
Meiotic Division ◽  
Germ Tube ◽  
Nuclear Staining ◽  
Diploid Nucleus ◽  
Spore Type ◽  
Acacia Koa ◽  
Nuclear Behavior ◽  
Germ Tubes

Recent observations showed that Uromyces koae Arthur in Stevens teliospores did not produce typical basidia or basidio-spores. The present study reveals that teliospores produced long germ tubes that are differentiated into wide proximal and narrow distal portions separated by a vesiclelike swelling. One or two extensive branches, each morphologically resembling the main tube, developed from individual germ tube cells. Nuclear staining revealed a single, presumably diploid nucleus in mature teliospores. One or more probable mitotic divisions in the main germ tube provided a diploid nucleus for each branch and for the main tube itself. Meiotic division of each nucleus produced a series of four smaller nuclei in the narrow portion of each branch and the main tube. The germ tubes may be modified basidia and serve as infectious hyphae in place of basidiospores.A formerly undescribed spore type associated with the teliospores is recognized as uredinial. This investigation shows that the life cycle of U. koae probably consists of four distinct stages, each on Acacia koa: the spermatial associated with the aecial on hypertrophied shoots, and the uredinial and telial together in discrete leaf pustules.

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 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 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.

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.

Polyploidy in Sporobolus virginicus (L.) Kunth

1979 ◽  
Vol 27 (4) ◽  
pp. 429 ◽  
Author(s):  
AR Smith-White
Keyword(s):  
Salt Marsh ◽  
Chromosome Number ◽  
Meiotic Division ◽  
Distribution Patterns ◽  
Meiotic Behaviour ◽  
Polyploid Complex ◽  
South Eastern ◽  
Sporobolus Virginicus ◽  
Eastern Australia ◽  
Tetraploid Cytotypes

Chromosome number and meiotic behaviour was examined in Sporobolus virginicus Kunth from south-eastern Australia. Var. minor Bail. forms a polyploid complex with diploid (2n = 20), triploid and tetraploid cytotypes. Meiosis in tetraploid plants of this variety is substantially normal, which indicates an alloploid origin. Var. virginicus, which has been found only in the tetraploid state, has irregular meiotic division, which suggests autoploidy. Most cytotypes were collected from sandy and well-drained situations along the coast. However, tetraploid var. minor plants were generally found in poorly aerated salt marsh swamps. This apparent edaphic adaption of tetraploid cytotypes may be important in explaining distribution patterns.

Karyotypic analysis of Polymyxa betae (Plasmodiophoromycetes) based on serial thin sections of pachytene nuclei

1983 ◽  
Vol 61 (12) ◽  
pp. 3202-3206 ◽  
Author(s):  
James P. Braselton
Keyword(s):  
Chromosome Number ◽  
Plasmodiophora Brassicae ◽  
Polymyxa Betae ◽  
Karyotypic Analysis ◽  
Thin Sections ◽  
Haploid Chromosome Number ◽  
Synaptonemal Complexes

Three pachytene nuclei of Polymyxa betae Keskin were reconstructed from serial thin sections. Thirty synaptonemal complexes (SCs) were counted, indicating a haploid chromosome number of 30. SCs of Polymyxa were similar to those of Sorosphaera veronicae Schroeter and Membranosorus heterantherae Ostenfeld and Peterson but differed from SCs of Plasmodiophora brassicae Woron. and Woronina pythii Goldie-Smith.

scholarly journals Cytogenetic Studies inPapaverII. Hybrids Among Species with 7 as the Haploid Chromosome Number

Caryologia ◽  
1973 ◽  
Vol 26 (1) ◽  
pp. 13-25 ◽  
Author(s):  
C. P. Malik ◽  
I. S. Grover
Keyword(s):  
Chromosome Number ◽  
Haploid Chromosome Number ◽  
Cytogenetic Studies

Recherches sur les Alaria (Phaeophyceae) de l'est canadien. I. Nombres chromosomiques et identité des Alaria de l'estuaire du St-Laurent

1974 ◽  
Vol 52 (4) ◽  
pp. 691-694 ◽  
Author(s):  
M.-J. Feller-Demalsy ◽  
P. Demalsy
Keyword(s):  
Chromosome Number ◽  
Single Species ◽  
Chromosome Counts ◽  
Eastern Canada ◽  
Lawrence Estuary ◽  
Haploid Chromosome Number ◽  
Biosystematic Study ◽  
Alaria Esculenta ◽  
St Lawrence Estuary

Chromosome counts in gametophytes and sporophylls of Alaria collected in the St. Lawrence Estuary show that all the specimens of this genus in eastern Canada may not belong to the single species A. esculenta Greville. Indeed, the haploid chromosome number (n) found in these algae is equal to half of the number attributed in the literature to Alaria esculenta from the British coasts. Three hypotheses for the interpretation of these observations are considered. The solution of the problem of the identity of Alaria can only be hoped for from their global, morphological, and biosystematic study.

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