We report the karyotype characteristics including chromosome numbers of Saga campbelli campbelli, S. c. gracilis, and S. rammei using the following classical cytogenetic methods: C-banding, silver staining, and fluorochrome staining DAPI and CMA3. We also present FISH data showing the distribution of telomeric repeats and 18S rDNA on the chromosomes of these species and the results of similar studies cited in the literature on S. hellenica, S. natoliae, and S. rhodiensis. The five European Saga species exhibit a high rate of karyotype evolution. In addition to changes in chromosome number and morphology (by chromosomal inversion and/or chromosome fusion), interspecific autosomal differentiation involved changes in the distribution and quantity of constitutive heterochromatin and GC-rich regions, as well as the number and location of NORs. In the present study we focused on testing a hypothetical model of karyotype evolution in Saga, with particular reference to the cytogenetic mapping of rDNA and telomeric sequences. Variation in the distribution of rDNA and location of Ag-NORs are novel phylogenetic markers for the genus Saga.
A cytogenetic investigation was performed in eight species of the spittlebug genus Philaenus using silver-NOR (AgNOR)-banding and fluorescence in situ hybridization (FISH) with 18S rDNA and (TTAGG)n telomeric probes. This is the first application of FISH technique in the Auchenorrhyncha, a suborder of the Hemiptera. FISH along with the rDNA probe revealed differences between species in the number and chromosomal location of major ribosomal RNA gene sites, the so-called nucleolar organizer regions (NORs). However, we found a lack of perfect correlation between the results of AgNOR-staining and rDNA-FISH in the detection of NORs. FISH with the telomeric probe confirmed that the chromosome ends of the Philaenus species are composed of the (TTAGG)n nucleotide sequence, which is a common motif of insect telomeres., Anna Maryanska-Nadachowska, Valetnina G. Kuznetsova, Tatyana V. Karamysheva., and Obsahuje seznam literatury
The present study focused on the evolution of the karyotype in 21 taxa of the genus Isophya, which was done by mapping the location on the chromosomes of ribosomal RNA (rRNA) coding genes using fluorescence in situ hybridization (FISH) with an 18S rDNA probe and using silver staining (AgNO3) to evaluate the activity of major rDNA clusters. Since the chromosome number and sex determination do not vary in this genus, the above markers were used in a detailed comparison of the cytogenetic features of species of Isophya. The species analyzed were placed into three groups based on the location of rDNA on their chromosomes: (1) rDNA-FISH signals only on the two long pairs of autosomes, (2) rDNA-FISH signals on one long and one short pair of autosomes, and (3) rDNA-FISH signals on three to five different sized pairs of autosomes. These groupings partly correspond to the morphological groupings proposed in earlier studies. One long pair of autosomes frequently carried rDNA in all the Isophya species and probably is a plesiomorphic character for these taxa. The cytogenetic mapping revealed great variability among Isophya species in the chromosomal location of major rDNA clusters. Our results suggest that the observed variation in the number of rDNA clusters can be an important species-group specific phylogenetic marker. Analysis of 18S rDNA hybridization signals showed that the evolutionary dynamics of rDNA in this genus is remarkably high and accompanied by changes in the structure of chromosomes bearing rDNA at an inter- and intra-specific level. The telomeric sequence (TTAGG)n hybridized with the termini of most of chromosomes, however, some chromosome ends lacked signals probably due to a low copy number of telomeric repeats. and Beata Grzywacz, Anna Maryańska-Nadachowska, Dragan P. Chobanov, Tatjana Karamysheva, Elżbieta Warchałowska-Śliwa.
Diachasmimorpha longicaudata (Hymenoptera: Braconidae) is a parasitoid wasp widely used in the biological control of fruit flies. In this paper, we present a detailed analysis of the karyotype of this species based on the results of classical and molecular cytogenetic techniques. The cytogenetic analysis confirmed the male and female chromosome numbers previously reported (n = 20, 2n = 40). The entire short arm of most chromosomes is made up of a large constitutive heterochromatic segment. The high heterochromatin content differentiates D. longicaudata from other braconid species. Fluorescence in situ hybridization (FISH) using autologous 18S rDNA probes revealed six clusters of rDNA, i.e. six nucleolar organizer regions (NORs), in the heterochromatic short arms of different chromosomes in the haploid male karyotype. This number is exceptionally high for Hymenoptera, which usually have two NORs in the diploid complement. It is noteworthy that these rDNA-FISH experiments represent the first use of this technique on a braconid species using autologous probes. Since Ag-NOR-bands were coincident with C-positive bands on metaphase chromosomes, it was not possible to identify active nucleoli. The physical characteristics of the D. longicaudata karyotype, especially the content and distribution of heterochromatin and the number and location of rDNA clusters, contribute to a better understanding of the structure and organization of braconid chromosomes and provide a basis for genomic and evolutionary studies., Leonela Carabajal Paladino ... [et al.]., and Obsahuje seznam literatury
1_Chromosomes of six European species (one with two subspecies) of Orthoptera belonging to the tribes Ephippigerini and Bradyporini were analyzed using C-banding, Ag-NOR, DAPI (AT-rich)/CMA3 (GC-rich) staining and fluorescence in situ hybridization (FISH) using the 18S rDNA and (TTAGG)n telomeric probes with the aim to better understand chromosomal organization and evolutionary relationships between genera and subgenera within and across both tribes. The evolution of karyotypes was studied in terms of changes in chromosome number (2n) and morphology (FN, the fundamental number – i.e. the number of chromosome arms including the X chromosome). The ancestral 2n = 31 was reduced to 2n = 29 (FN = 31) and 27 (FN = 31) by one or two Robertsonian fusions in the Ephippigerini. Whereas in the Bradyporini 2n = 27 (FN = 32) as a result of two Robertsonian translocations and a pericentric inversion in the X chromosome. The quantity of heterochromatin in GC-rich regions distinguished the karyotypes of Ephippigerini (only a single CG-rich band on one autosome pair) from those of Bradyporini (CG-rich bands on all chromosomes). FISH using the 18S rDNA probe localized 1–3 rDNA clusters to autosomes and/or to the X chromosome in all species examined. The rDNA loci coincided with active NORs as determined by Ag-NOR staining. A comparison of the location of the single NOR/rDNA in two species of the genus Steropleurus (Ephippigerini) suggests that the reduced chromosome number in S. pseudolus results from a Robertsonian fusion between two pairs of autosomes, one of them carrying the NOR/rDNA as in S. stalii (and also in E. ephippiger)., 2_Whereas the karyotypes of three species of the genus Bradyporus, though showing the same chromosome number and morphology, differed in the number and distribution of NORs/rDNA sites [one autosomal in B. (B.) dasypus versus three in B. macrogaster and B. (C.) oniscus, two of them X-linked]. Trends in karyotype diversification of the taxa based on the present data and previous research are discussed. In some individuals belonging to the species Bradyporus (B.) dasypus and B. (C.) m. macrogaster B chromosomes (Bs) were detected: acrocentric (the smallest elements in the complement) and submetacentric (similar to medium-sized autosomes), respectively., Elzbieta Warchalowska-Sliwa ... [et al.]., and Obsahuje seznam literatury
The lung-dwelling nematode Rhabdias engelbrechti sp. n. was found in five of eight examined banded rubber frogs in Limpopo Province, South Africa. The species is differentiated from species of Rhabdias Stiles et Hassall, 1905 occurring in the Afrotropical Realm based on the presence of a globular cuticular inflation at the anterior end, the buccal capsule walls being distinctly divided into anterior and posterior parts, the buccal capsule size (6-9 μm × 16-18 μm), and the body length (3.8-6.1 mm). Rhabdias engelbrechti is the tenth species of the genus found in Afrotropical anurans. Our molecular phylogenetic analysis based on the complete sequences of the ITS region and partial sequences of large subunit (28S) gene of the nuclear ribosomal RNA demonstrates that the new species is more closely related to the Eurasian species Rhabdias bufonis (Schrank, 1788) than to two other species from sub-Saharan Africa represented in the tree. In addition, partial sequences of the mitochondrial protein coding cox1 and ribosomal 12S genes of the new species have shown significant differences from all previously published sequences of these genes from African species of Rhabdias., Yuriy Kuzmin, Ali Halajian, Sareh Tavakol, Wilmien J. Luus-Powell, Vasyl V. Tkach., and Obsahuje bibliografii
Multivalvulid myxosporeans of the genera Kudoa Meglitsch, 1947 and Unicapsula Davis, 1924 (Cnidaria: Myxozoa) are often the cause of unsightly cyst formation or postmortem myoliquefaction in the trunk muscle of commercial marine fish, which reduces the market value of infected individuals. Twenty species (18 Kudoa spp. and two Unicapsula spp.) have been recorded from carangid fish, although the majority of them, excluding polyxenous species, such as K. amamiensis Egusa et Nakajima, 1980, K. iwatai Egusa et Shiomitsu, 1983, K. nova Naidenova, 1975, K. quadratum (Thélohan, 1895) and K. yasunagai (Hsieh et Chen, 1984), are limited to a single or a few fish species. We report the occurrence of macroscopic cysts of Kudoa trachuri Matsukane, Sato, Tanaka, Kamata et Sugita-Konishi, 2011 in the trunk muscle of four new host fish species, i.e., Pseudocaranx dentex (Bloch et Schneider), Decapterus akaadsi Abe, D. muroadsi (Temminck et Schlegel) and Decapterus tabl Berry, fished from the Philippine Sea (Northwest Pacific Ocean), off southwestern of Japan. Myxospore morphology and genetic characteristics of the ribosomal RNA gene (rDNA) of these isolates were consistent with previous records of K. trachuri from Trachurus japonicus (Temminck et Schlegel) from around Japan. In addition, a new species of Kudoa that forms long filamentous pseudocysts in trunk myofibres was found in four of the six D. tabl collected in this study. We describe Kudoa longichorda sp. n. for this new isolate, based on its morphology of subquadrate myxospores with four shell valves and polar capsules and with small dimensions (length 4.3-5.5 µm, width 6.0-6.8 µm, thickness 4.8-6.3 µm, polar capsule length 2.3-3.1 µm, polar capsule width 1.1-1.7 µm), as well as 18S and 28S rDNA sequences distinct from those of known species.
Heterochromatin is one of the most dynamic components in the genome of species. Previous studies on the heterochromatin content and distribution in Heteroptera (insects with holokinetic chromosomes) have shown that the species belonging to the family Coreidae are interesting model organisms since they show very diverse C bands patterns. In the present work, we analyzed the C-band pattern in individuals of Holhymenia rubiginosa from different populations collected in different years. This species has the diploid karyotype 2n = 27/28 = 24 + 2m + X0/XX (male/female). C-bands are terminally, subterminally or interstitially located on 10-17 chromosomes and a remarkable heterochromatin heteromorphism is observed in the meiotic bivalents: in the presence/absence of bands, in the size of bands and number of bands. A heteromorphism is also inferred in the number of ribosomal genes from the difference in the fluorescent in situ hybridization signals between NOR-homologues. Chiasmata are generally located opposite to conspicuous C-bands, but in some bivalents chiasmata are also observed in close proximity to C-bands. Considering the striking variation in heterochromatin content between individuals and populations it is suggested that heterochromatin should be selectively neutral in H. rubiginosa.
The karyotype of bream Abramis brama was analysed by means of C-banding, replication banding, DAPI fluorescent staining and in situ hybridisation with 18S rDNA and telomeric probes. The use of the in vivo 5-bromodeoxyuridine incorporation technique enabled the induction of replication bands of the RBA type in the karyotype. C-bands corresponded to late replicated chromosome regions. 18S rDNA clusters were found on one chromosome pair. Telomeric sequences were observed only on ends of chromatids. The karyotype morphology and NOR phenotype of A. brama are very similar to those found in other species of the leuciscine cyprinids karyotyped so far.
Mango orchards in Pakistan are attacked by the scale insect, Drosicha mangiferae (Hemiptera: Monophlebidae), commonly called the "mango mealybug". This insect is univoltine, active from December through May and targets multiple host plants. We used DNA nucleotide sequences to characterize and determine the phylogenetic status of D. mangiferae. Mango mealybugs were collected from several tree species from different localities and patterns of phylogenetic and genetic diversity were examined at both nuclear (18S, ITS1) and mitochondrial (COI) genes. Phylogenetic analysis confirms that the mango mealybug belongs to the family Monophlebidae. Minor genetic differences in both the ITS1 and the COI barcode region were noted among D. mangiferae collected from different geographic localities. These genetic differences revealed the existence of two genotypes of D. mangiferae that are region specific but not host-specific. and Muhammad Ashfaq, Jehan Ara, Ali Raza Noor, Paul D.N. Hebert, Shahid Mansoor.