Evolutionary study on two closed Gammarus (Crustacea, Amphipoda) species from Zagros Mountains (Iran) using molecular methods

Mitochondrial Cytochrome Oxidase Subunit I DNA sequences are a good discriminative marker for phylogenetic studies in crustaceans and especially in amphipoda. In the present study, molecular and morphological data were analyzed to test whether Gammarus lobifer authority and Gammarus balutchi authority which [sic] one or two geographically separated but morphologically similar species. The analyses proved that there are two species and that uplift of the Zagros Mountains was probably the most important cause of Allopatric speciation in this region during the Miocene period

Substrate induced proximity effect in superconducting niobium nanofilms

Structural and superconducting properties of high quality Niobium nanofilms with different thicknesses are investigated on silicon oxide and sapphire substrates. The role played by the different substrates and the superconducting properties of the Nb films are discussed based on the defectivity of the films and on the presence of an interfacial oxide layer between the Nb film and the substrate. The X-ray absorption spectroscopy is employed to uncover the structure of the interfacial layer. We show that this interfacial layer leads to a strong proximity effect, specially in films deposited on a SiO$_2$ substrate, altering the superconducting properties of the Nb films. Our results establish that the critical temperature is determined by an interplay between quantum-size effects, due to the reduction of the Nb film thicknesses, and proximity effects

The effect of onboard passengers’ seating arrangement on the vertical ride comfort of a high-speed railway vehicle

This research is concerned with the impact of onboard passengers’ seating arrangement on the carbody flexural vibrations of a high-speed railway vehicle. In this regard, the previously developed passenger body-seat models are used to consider the dynamic influence of the passengers. The carbody is modeled using the Euler–Bernoulli beam model to evaluate its flexural deformation. The frequency-domain analysis demonstrates that the carbody behaves almost like a rigid body when the vehicle is full of passengers. It is established that the passengers' presence causes a 31% enhancement of the ride quality determined based on EN 12299 standard for a fully occupied vehicle compared with an empty car. A scaled model of a ratio of 1:24.5 of the Shinkansen vehicle is constructed for validation purposes. The experimental results exhibit a similar trend as found by the simulations in terms of the impact of the passengers’ distribution on the carbody flexural vibrationsPostprint (author's final draft

Population structure of Acipenser nudiventris in the south coast of Caspian Sea and Ural River using microsatellite method

Population structure of Ship sturgeon, Acipenser nudiventris, from the south coast of Caspian Sea and Ural River was investigated using Microsatellite method. For this reason, 73 specimens of the sturgeon were collected from five locations in two sampling regions the first consisted of Bandar Anzali, SefidRud River, Babolsar, and Gorgan, and the second was Ural River. Four SSR markers were used in this investigation, of which 5 loci produced DNA band, with three of them being polymorph. One primer showed two loci with one of them being polymorph and another was monomorphic). Average expected and observed heterozygosity was 0.86 and 0.75 respectively. Genetic variation was assessed through analysis of molecular variance (AMOVA) that indicated almost all of the variance in data namely %94 (P less than or equal to 0.03) was within locations

Genetic difference and resemblance between Acipenser persicus and Acipenser gueldenstaedtii by means of RAPD Technique

We studied genetic difference and resemblance between Acipenser persicus and Acipenser guldenstaediii using Random Amplified Polymorphic DNA (RAPD) technique. The DNA of tail fin tissue of three A. persicus and A. gueldenstaedtii were extracted using phenol-chloroform method. After electrophoresis of the samples by agarose gel, their concentrations were regulated and Polymerise Chain Reaction (PCR) was conducted by 53 primers. PCR products were electrophoresed on polyacrylamide gel and silver staining was done to reveal the DNA bands of the samples. Among 53 primers, 17 had no site on genomic DNA of A. persicus and A. gueldenstaedtii and did not produce any bands while the remaining 36 primers showed band pattern. Analyzing the PCR products data using RAPD PLOT program showed that the maximum and minimum genetic distance between species were 73% and 65% respectively. Also, the mean difference between the species was 70% and the maximum and minimum genetic resemblance between the two species were 35% and 27% respectively. Based on the results, we conclude that A. persicus is an independent species from A. gueticienstaeditii

A phylogeny analysis on six mullet species (Teleosti: Mugillidae) using PCR-sequencing method

In this study, genetic differences and phylogenic relationships among six Mugillidae species (Mugil cephalus, M. capito, Liza subviridis, L. saliens, L. aurata, Valamugil buchanani) were determined using PCR-sequencing. M. cephalus, L. subviridis, and V. buchanani from the Persian Gulf and Oman Sea, and L. aurata and L. saliens from the Caspian Sea were collected. Samples of an imported, Egyptian species M. capito were obtained from the Gomishan Research Center in Gorgan. Total DNA from the samples were extracted according to phenol-chloroform procedure. The extracted total DNAs were amplified using polymerase chain reaction (PCR) and then sequenced. The number of bases in the mitochondrial 16s rRNA genome used in this study approximated 600 base pairs. The size of the bands was identical in all the studied species and no heteroplasmia was observed. In addition, the numbers of variable, preserved, and Pi sites were about 114/624, 488/624, and 110/624, respectively. Analysis of the sequences showed great differences between Mugil species and the other studied species. The phylogenetic tree obtained through Neighbor-Joining method revealed that L. saliens and L. aurata were in the same branch while L. subviridis was in a separate branch. In contrast, Maximum Parsimony tree located L. subviridis and L. aurata in a single branch and assigned L. saliens to a distinct branch. This result brings in the question of monophyletic origin of the genus Liza

Genetic relationships of Iranian coastline ship sturgeon (Acipenser nudiventris) samples and Ural population based on microsatellite DNA

Genetic relationships among 96 specimens of ship sturgeon, Acipenser nudiventris, collected from six locations along the Iranian coastline as well as 8 specimens from northern population (Ural River) were analysed by the restricted maximum likelihood method, as well as two distance analysis method (Nei's and Cavalli-Sforza's distance) of gene frequencies. We have used four SSR markers that produced three polymorphic and two monomorphic loci. Overall results showed that Iranian coastline samples form a monophyletic group (clade) which was different from the northern (Ural) samples. Iranian coastline samples are divided into two groups (clades): Anzali-Kiashahr clade and Sefidrud-Babolsar-Noushahr-Gorgan clade. Bootstrapping test showed monophyleticity of Sefidrud, Babolsar, Noushahr, Gorgan with high (Bootstrap support=93) and Anzali-Kiashahr with middle (Bootstrap support=65) confirmation. Topology of reconstructed trees was in correspondence with geographical distributions of samples

Investigation on genetic structure of Russian sturgeon (Acipenser gueldenstaedtii) populations of the north (Volga River) and south Caspian Sea (coasts of Iran and Turkmenistan) using microsatellite techniques

A total of 28 specimens of adult Russian sturgeon brood fish from the Volga River (Astrakhan, Russia) and 42 specimens from the south Caspian Sea (coastline of Iran and Turkmenistan) were collected. About 2g of fin tissue was stored in 96% ethyl alcohol and transferred to the genetic laboratory of the International Sturgeon Research Institute. Genomic DNA was extracted using phenol-chloroform method. The quality and quantity of DNA was assessed by Agarose gel electrophoresis and spectrophotometry. Polymerase Chain Reaction (PCR) was conducted using eight pairs of microsatellite primers and its products were electrophoresed using 6% polyacrylamide gel followed by silver nitrate staining. Allele sizes were measured in all populations, then genetic parameters were calculated using Gen Alex program and the phylogenetic relationship was determined and drawn using TFPGA program. A minimum of 10 and a maximum of 21 alleles were identified per locus and the observed heterozygosity ranged between 0.50-0.96 and the expected heterozygosity was 0.74-0.90 with an average of 0.68. Hardy-Weinberg equilibrium was observed at Ls-19, Ls-39 loci, but showed disequilibrium in other loci. FST index between Volga and South Caspian Sea samples was 0.031. The genetic similarity and distance was 0.661 and 0.414, respectively. Results of the present investigation indicate that there are no significant differences between the south Caspian Sea Russian sturgeon specimens