2,511 research outputs found

    Morphologic and meristic specification of some genus of Carangidae family in the Persian Gulf, Iran

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    Morphologic and meristic analyses were performed aided by regression charts on 96 specimens of the genus Parastromateus, 67 specimens of Caranx, 70 specimens of Alepes, 69 specimens of Scomberoides, 62 specimens of Atropus, 104 specimens of Carangoides, and 67 specimens of Trachionotus from March 2004 to February 2005. The samples were collected by using bottom trawling in the Persian Gulf. The analyses showed the complete separability of the genus while keeping their close connection with the Family. We found that Parastrometeus was specially unique in terms of keeping its relationship with the family Carangidae

    Polymerase Chain Reaction (PCR) and direct sequencing of mtDNA from the ND5/6 gene region in Persian sturgeon Acipenser persicus from the southern Caspian Sea

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    A partial sequence of the mtDNA ND5 gene region was used for population study in Persian sturgeon (west and east areas of southern Caspian Sea). The result showed that although this approach was informative for phylogenetic study in sturgeon, it was less informative for population study in Persian sturgeon

    Substrate induced proximity effect in superconducting niobium nanofilms

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    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 SiO2_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

    Identification of white spot syndrome disease (WSSD) in Penaeus indicus by polymerase chain reaction (PCR) method in Iran

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    A high mortality of cultured shrimp Penaeus indicus was spotted in summer 2002 in Khouzestan province, southwestern Iran. White spots with a size of 0.5-2mm was one of the typical external signs of the infected shrimps. Our examination revealed that the cuticle of the shrimps could be easily separated from their epidermis, their hepatopancreas was swollen, their abdomen and intestine were empty and their body colour was reddish. Based on the symptoms, we suspected that white spot syndrome disease (WSSD) might have caused the mortality. To ascertain our suspicion, we collected 90 infected specimens from the Khouzestan province and another 120 uninfected specimens from Bushehr and Hormozgan provinces in the south and Golestan province in the northeast Iran. After fixing the samples in pure alcohol, we homogenized the samples and extracted their DNA content using phenol-chloroform methods. Using a WSSD kit, we conducted the PCR method which showed the specimens from Khouzestan province (Abadan area) were definitely infected with WSSD while results for samples from other provinces were negative

    Karyology of Abramis brama in the southern waters of Caspian sea

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    The karyology of bream (Abramis brama) were done for the first time in Iran. This study was conducted on chromosomal number, chromosome arms and karyotyping of bream from the -Southern part of the Caspian Sea with preparing chromosomal extensions on the base of Squash method. The number of metaphase plates using Squash method on renal and gill tissues was determined as to be 2n=50 and the number of chromosome arms was NF=82. The prepared karyotype of this species was consisted of 8 pairs of metacentric, 8 pairs of submetacentric and 9 pairs of acrocentric chromosomes

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

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    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

    Identification of different species of squids in Oman Sea (Iranian waters)

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    Identification of different species of oceanic and neritic squids in Iranian waters of Oman Sea was carried out from December 1996 to February 1997. The trawl surveys were conducted during a 12-months period. Fishing was also undertaken by Mid-water and bottom trawl for species confirmation purposes in deep (200-350m) and shallow (0-100m) waters to collect enough specimens that could be used for later species identification. The RN Ferdows-I was used for sampling with an approximate hauling speed of 3.0 knots. Three oegopsid species including Ancistrocheirus lesueuri, Liocranchia reinhardti, Sthenoteuthis oualaniensis and neritic squid, Loligo duvauceli were identified. Another loliginid squid different from Loligo duvauceli was also observed. A. lesueuri (Enoploteuthidae Family) and Liocranchia reinhardti (Cranchiidae Family) are here reported from this area for the first time. Neither was any report about these two families of oegopsid squids in Oman Sea nor Persian Gulf

    Short communication: Population genetic structure studies of Liza aurata based on mtDNA control region sequences analyses in the southern coasts of the Caspian Sea

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    Nowadays many species are endangered as a result of habitat loss. Decreases in population lead to reduced genetic diversity, which can cause survival crisis in a population (Cecconi et al., 1995). Nowadays optimal management of fish stocks needs information on population structure of species that is provided to researchers through genetic science. Bereavement of science about stock composition will lead to the fracture of fisheries management and unsuitable harvest of stocks (Papasotiropoulos et al., 2007). One of the beneficial methods to demonstrate genetic diversity is haplotype analysis of the D-loop region, an index which is very important and determinant for the preservation of species. Significant genetic variation is found in the D-loop region, even among individuals within a given species. Grey mullets are not endemic species of the Caspian Sea. Juveniles of L. aurata, L. saliens and Mugil cephallus were introduced from the Black Sea into the Caspian Sea during the years 1930-1934. But only the introduction of L. aurata and L. saliens was successful and they adapted well to the ecological conditions of the Caspian Sea (Fazli et al., 2008)

    Molecular population study on Penaeus semisulcatus from the Persian Gulf and Oman Sea using cytochrom oxidase subunit I (COI) gene by RFLP method

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    The objective of this investigation was molecular population study on Penaeus semisulcatus stocks from the Persian Gulf and Oman Sea. Samples were collected using trawling method from Hormuz (40 individuals) and Bushehr (35 individuals) regions. The DNA of samples were extracted using phenol and chloroform method and then were simplified using a pair premier of Cytochrom Oxidase Subunit I (COI) gene sequence by a thermal cycler. Nine restriction enzyme were Used to digest the larger gene region that five of them (Alu I, Hinf I, Hinc I I, Hpa I I and Rca I) appeared Polymorphic patterns. Reap software and X^2 test were used to analyses the RFLP data. The average nucleotide diversity arid haplotype diversity among the population were 0.0345720 ± 0.0011952 and 0.28590±0.08174 and nucleotide divergence among population, being studied, is supposed to be 8.5%. Considering the result dispersion of haplotypes in two region showed a significant difference and this is an evidence for proving the variety of the stocks
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