Search results for "chromosome"
showing 10 items of 1175 documents
Characterization and chromosomal localization of the chicken avidin gene family
2000
Chicken avidin is a biotin-binding protein expressed under inflammation in several chicken tissues and in the oviduct after progesterone induction. The gene encoding avidin belongs to a family that has been shown to include multiple genes homologous to each other. The screening and chromosomal localization studies performed to reveal the structure and organization of the complete avidin gene family is described. The avidin gene family is arranged in a single cluster within a 27-kb genomic region. The cluster is located on the sex chromosome Z on band q21. The organization of the genes was determined and two novel avidin-related genes, AVR6 and AVR7, were cloned and sequenced.
Restriction analysis of lambda EMBL3 background recombinants: occurrence of lambda phages carrying a head to tail oriented left arm DNA sequence.
1989
Eight representative recombinant background clones of lambda EMBL3 were analysed using KpnI, BamHI, SalI, EcoRI and HindIII digestion. We found that lambda EMBL3 carries its own left arm in the BamHI cloning site. In the way, recombinant molecules were found to be generated which can grow on Escherichia coli strain NM539. In all cases analysed, the left arm DNA was inserted in a head to tail orientation. Seven clones carried a restored BamHI site at the cos site-BamHI site connection. In the region where the inserted left arm and the right arm were ligated, BamHI cloning produces a large palindromic sequence consisting of two polylinkers. This BamHI site was incompletely cleaved in all case…
Characterization of mitotic and meiotic, chromosomes of the vermetid gastropodDendropoma (Novastoa) Petraeum(Monterosato, 1884) (Mollusca, Caenogastr…
1997
Abstract The vermetid gastropod Dendropoma (Novastoa) petraeum from the Northwestern coast of Sicily was investigated karyologically. The count of spermatocyte bivalents at diakinesis gave the haploid number of this species as n=17. The count of mitotic chromosomes in males, females and early developing embryos gave the diploid number as 2n=34. Irrespective of sex, the karyotype of D. petraeum consists of 17 homomorphic chromosome pairs, of which 8 are metacentric, 4 subtelocentric and 5 acrocentric. This species is characterized by the presence of two chromosomes per cell involved in nucleolus organization (NOR) and by a low amount of constitutive heterochromatin.
Inter- and intraspecific chromosome pattern variation in the yeast genusKluyveromyces
1998
The analysis of the electrophoretic chromosome patterns of the species of the genus Kluyveromyces, reveals a high polymorphism in size, number and intensity of bands. DiVerent sets of electrophoresis running conditions were used to establish species-specific patterns and also to detect intraspecific variation. According to their karyotypes, the species of this genus can be divided into two major groups. The first group includes the species K. africanus, K. bacillisporus, K. delphensis, K. lodderae, K. phaY, K. polysporus and K. yarrowii, composing the so-called ‘Saccharomyces cerevisiae-like’ group, because their karyotypes resemble that of the species S. cerevisiae. The second group compri…
Spermatocyte chromosome analysis of the slugLehmannia melitensis(Lessona and Pollonera, 1891) (Mollusca, Pulmonata) using conventional, NOR- and C-ba…
1993
SUMMARYDiploid number 2n = 40 and haploid number n = 20 for the slug Lehmannia melitensis have been determined. These chromosome values being considerably different from those reported for slugs belonging to other limacid genera support the notion that the genus Lehmannia is particular within the family Limacidae. Nucleolus organizer regions (NORs) and C-banding pattern of L. melitensis are described.
Centrosome structure is very similar in eupyrene and apyrene spermatocytes ofEphestia kuehniella(Pyralidae, Lepidoptera, Insecta)
1997
Summary The higher Lepidoptera produce two types of sperm, eupyrene and apyrene. Eupyrene spermatozoa are fertile, while apyrene spermatozoa are anucleate and, therefore, sterile. Meiosis differs between the two developmental lines. One of the most obvious differences is the aberrant organization of the apyrene spindles. They possess fewer microtubules than eupyrene spindles and chromosome segregation is irregular. To determine whether micotubule nucleation is impaired in the aprene spindles, the present fine structure study concentrated on the centrosomes in both spermatocyte types. In addition, the presence of gamma-tubulin, a newly discovered tubulin isoform which is prevalent in centros…
Flow Cytometry and Karyotype Analysis ofD. melanogasterEye Disc Cells
2008
The developing Drosophila eye-antennal disc is a particularly suited system for the genetic and cellular studies of complex biological processes. Methods to analyze Drosophila eye discs by flow cytometry are mainly based on the dissociation of tissues with trypsin. Dissociation operated by trypsin is very effective, though it causes a lot of stress to live cells often compromising the use of treated cells for further analyses. Here, we report a method to produce dissociated eye-disc cells that retain cell-membrane markers and that can be used for flow cytometry and cytological analysis of mitotic chromosomes. The method described is a great complementing tool for the cellular characterizati…
Cytogenetic characterization ofBrachidontes pharaonis(Fisher P., 1870): Karyotype, banding and fluorescentin situhybridization (fish) (Mollusca: Biva…
2000
Abstract The mussel Brachidontes pharaonis (Fisher P., 1870) (Bivalvia: Mytilidae) has a diploid chromosomal set of 28 made up of 14 pairs of which eight are mono-armed (ST) and six bi-armed (M+SM). Fourteen bivalents occur in spermatocytes both at pachytene and metaphase-I. The use of combined silver and CMA3 staining reveals that nucleolus organizer regions (NORs) are located terminally on the long arm of a small subtelocentric chromosome pair (pair 14) and are compartmentalized in GC base pairs. A Paracentrotus lividus (Echinodermata) 4.3 kilobase (kb) rDNA probe (prR14) consisting of sequences from the 3′ end of 18S rDNA to the 3′ end of 26S rDNA was used to map the rDNA loci of B. phar…
Fanconi anemia (FA) and crosslinker sensitivity: Re-appraising the origins of FA definition
2015
The commonly accepted definition of Fanconi anemia (FA) relying on DNA repair deficiency is submitted to a critical review starting from the early reports pointing to mitomycin C bioactivation and to the toxicity mechanisms of diepoxybutane and a group of nitrogen mustards causing DNA crosslinks in FA cells. A critical analysis of the literature prompts revisiting the FA phenotype and crosslinker sensitivity in terms of an oxidative stress (OS) background, redox-related anomalies of FA (FANC) proteins, and mitochondrial dysfunction. This re-appraisal of FA basic defect might lead to innovative approaches both in elucidating FA phenotypes and in clinical management.