Karyotype analysis and chromosome number for two Cirsium taxa (Asteraceae) in Iran

Cirsium Mill. contains more than 250 species in the world mainly distributed in the Northern hemisphere. Different chromosome numbers with different ploidy levels were reported in this genus. In this study, karyotype details and chromosome numbers were established for two Cirsium taxa in Iran. C. ciliatum subsp. szovitsii and C. echinus had the mitotic chromosome numbers of 2n = 2x = 34. Karyotype analyses showed that chromosomes were generally metacentric and sub-metacentric. In C. echinus, Lowshan population had the longest chromosome (19.10 µm) and Heyran Canyon population (4.73 µm) the shortest one while in C. ciliatum, the longest chromosome was observed in Urmia to Salmas population (14.67 µm) and the shortest one (4.71 µm) in Doshanlu population. Total haploid chromosome length ranged from 275.29 to 376.42 µm in populations studied. Both taxa were grouped in 2B class. B-chromosomes were recorded for two taxa studied too. Chromosome type, mitotic chromosome numbers and occurrence of B-chromosomes were in agreement with previous results (Albers, Pröbsting, 1998; Lövkvist, Hultgård, 1999; Yüksel et al., 2013; Yildiz et al., 2016).

Mode and Tempo of Microsatellite Evolution across 300 Million Years of Insect Evolution

Microsatellites are short, repetitive DNA sequences that can rapidly expand and contract due to slippage during DNA replication. Despite their impacts on transcription, genome structure, and disease, relatively little is known about the evolutionary dynamics of these short sequences across long evolutionary periods. To address this gap in our knowledge, we performed comparative analyses of 304 available insect genomes. We investigated the impact of sequence assembly methods and assembly quality on the inference of microsatellite content, and we explored the influence of chromosome type and number on the tempo and mode of microsatellite evolution across one of the most speciose clades on the planet. Diploid chromosome number had no impact on the rate of microsatellite evolution or the amount of microsatellite content in genomes. We found that centromere type (holocentric or monocentric) is not associated with a difference in the amount of microsatellite content; however, in those species with monocentric chromosomes, microsatellite content tends to evolve faster than in species with holocentric chromosomes.

Identification of a Type IV CRISPR-Cas system located exclusively on IncHI1B/IncFIB plasmids in Enterobacteriaceae

During an investigation of CRISPR carriage in clinical, multi-drug resistant, Klebsiella pneumoniae, a novel CRISPR-Cas system (which we have designated Type IV-B) was detected on plasmids from two K. pneumoniae isolates from Egypt (isolated in 2002-2003) and a single K. pneumoniae isolate from the UK (isolated in 2017). Sequence analysis of other genomes available in GenBank revealed that this novel Type IV-B CRISPR-Cas system was present on 28 other plasmids from various Enterobacteriaceae hosts and was never found on the chromosome. Type IV-B is found exclusively on IncHI1B/IncFIB plasmids and is associated with multiple putative transposable elements. Type IV-B has a single repeat-spacer array (CRISPR1) upstream of the cas loci with some spacers matching regions of conjugal transfer genes of IncFIIK/IncFIB(K) plasmids suggesting a role in plasmid incompatibility. Expression of the cas loci was confirmed in available clinical isolates by RT-PCR; indicating the system is active. To our knowledge, this is the first report describing a new subtype within Type IV CRISPR-Cas systems exclusively associated with IncHI1B/IncFIB plasmids.ImportanceHere, we report the identification of a novel subtype of Type IV CRISPR-Cas that is expressed and exclusively carried by IncHI1B/IncFIB plasmids in Enterobacteriaceae, demonstrating unique evolutionarily juxtaposed connections between CRISPR-Cas and mobile genetic elements (MGEs). Type IV-B encodes a variety of spacers showing homology to DNA from various sources, including plasmid specific spacers and is therefore thought to provide specific immunity against plasmids of other incompatible groups (IncFIIK/IncFIB(K)). The relationship between Type IV-B CRISPR-Cas and MGEs that surround and interrupt the system is likely to promote rearrangement and be responsible for the observed variability of this type. Finally, the Type IV-B CRISPR-Cas is likely to co-operate with other cas loci within the bacterial host genome during spacer acquisition.

Phylogenetic reconstruction and divergence time estimation of Blumea DC. (Asteraceae: Inuleae) in China based on nrDNA ITS and cpDNA trnL-F sequences

The genus Blumea DC. is one of the economically most important genera of Inuleae (Asteraceae) in China. It is particularly diverse in south China, where 30 species occur, more than half of which are used as herbal medicine or in the chemical industry. However, little is known about the phylogenetic relationships and molecular evolution of this genus in China. We used nuclear ribosomal DNA (nrDNA) internal transcribed spacer (ITS) and chloroplast DNA (cpDNA) trnL-F sequences to reconstruct the phylogenetic relationship and estimate the divergence time of Blumea DC. in China. Results indicated the genus of Blumea DC. was monophyletic and could be divided into two clades, the two clades were resolved that differ with respect to habitat, morphology, chromosome type and chemical composition, of their members. Furthermore, based on the two root time of Asteraceae, the divergence time of Blumea DC. were compare estimated. Results indicated the most recent common ancestor of Asteraceae maybe originated from 76-66 Ma, and Blumea DC. maybe originated from 72.71-52.42 Ma, and had an explosive expansion during Oligocene and Miocene (30.09-11.44 Ma), two major clades were differentiated during the Palaeocene and Oligocene (66.29-46.72 Ma), also the evidence from paleogeography and paleoclimate also supported Blumea DC. had an differentiation and explosive expansion during Oligocene and Miocene.

Cytogenetic Characteristic the Patients of Both Sexes with Phobic-anxiety Disorders

Background and aimsAnxiety-phobic disorders are caused both by environmental and hereditary factors. The study was designed to determine the level of chromosomal aberrations in the peripheral blood lymphocytes (PBL) of children and adolescents of both sexes with phobic-anxiety disorders (PAD).Patients and methodsCytogenetic analysis was performed in 27 children and adolescents of both sexes with PAD, aged 9–15 years; the control group consisted of 50 healthy peers of both genders. Statistical analysis-Excel and SPSS statistics 17.0.ResultsCytogenetic analysis of patients with PAD and in healthy age-matched individuals has established normal female (46,XX) and male (46,XY) karyotypes. The frequency of the chromosomal aberrations (CA) spontaneous level in the PBL is 4.6 times higher than the CA frequency in healthy persons. In children and adolescents with the disease, the spontaneous frequency of aberrations of chromatid and chromosome types is also significantly higher than the same in healthy children and adolescents. Single acentric fragments and exchanges prevail among the chromatid–type aberrations; pair acentric fragments prevail among the chromosome–type aberrations. An increase in the frequency of the chromosome-type aberrations has been revealed in boys with PAD (1.72 vs.0.55 per100 cells in healthy boys, P < 0.001 by pair acentric fragments), in comparison with healthy boys; and the chromatid–type aberrations have been observed in girls with PAD (3.22 vs.0.94 per 100 cells in healthy girls, P < 0.001 by single acentric fragments), in comparison with healthy girls. A pronounced individual variability of CA frequency, which ranges in our patients from 2.0 to18.0 per 100 metaphase plates, has been found along with an increase in the CA level in patients with PAD.ConclusionChildren and adolescents with PAD require a careful cytogenetic analysis and the consequent therapeutic measures for genome stabilization.Disclosure of interestThe authors have not supplied their declaration of competing interest.