28 research outputs found

    Influence of Different Concentrations of Salt Stress on In Vitro Multiplication of Some Fig (Ficus carcia L.) Cultivars

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    This work aimed to establish in-vitro plant formation from Ficus carica L. cultivars (i.e., Black Mission, Brown Turkey and Brunswick) and investigate their salt tolerance using different concentrations of NaCl. Plant growth regulators BAP, Kinetin, 2iP and NAA were evaluated during proliferation, elongation and rooting stages. Murashige and Skoog (MS) was the most superior medium for increasing explant development in most tissue culture techniques for all cultivars. BA was the best cytokinin for enhancing proliferation in cvs. Brown Turkey and Brunswick, while Kinetin was more effective in improving growth and greening parameters of cv. Black Mission. Shoot elongation of cv. Black Mission was increased by using hormone-free media. Shoot elongation was enhanced by addition of 0.5 mg L-1 GA3 to the culture medium of cv. Brunswick, while 1.0 mg L-1 was better for cv. Brown Turkey. IBA at 2.0 mg L-1 was most effective in maximizing cv. Brown Turkey rooting, while 1.5 mg L-1 was the best for the other cultivars. Half strength MS medium produced the best root formation compared to other media strengths. NaCl at concentrations of more than 12 g L-1 induced lethal effects on all parameters under study and 11 g L-1 had adverse effect on the plantlets of cv. Brunswick. Contents of K+, Na +, Fe++ and Zn++ increased incrementally with increasing NaCl levels in all cultivars. cv. Brown Turkey accumulated more K+ and Na+ than others

    Responses of three tomato cultivars to sea water salinity 1. Effect of salinity on the seedling growth

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    The effect of sea water salinity (1500, 2500 and 3500 ppm) on the growth of tomato (Lycopersicon esculentum) cultivars (Trust, Grace and Plitz) was studied. The sea water salinity delayed seed germination and reduced germination percentage especially with increasing salinity level. Chlorophyllb content was higher than chlorophyll a, and both of them decreased with increasing salinity. The seedling height increased with time but decreased with increasing salinity in all cultivars. Seedlings fresh and dry shoot and root weights were decreased with increasing salinity. The growth of stem, leave and root after over 80 days of exposure to sea water salinity was affected by sea water dilution especially those of trust and grace cultivars. The grace cultivar was less affected by sea water salinity on the germination stage, while the plitz cultivar has good tolerant to sea water salinity for prolonged perio

    Molecular cloning and expression of a vacuolar Na<sup>+</sup>/H<sup>+</sup> antiporter gene (AgNHX1) in fig (Ficus carica L.) under salt stress

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    Soil salinity can be a major limiting factor for productivity in agriculture and forestry and in order to fully utilize saline lands productively in plantation forestry for fig production, the genetic modification of tree species for salt tolerance may be required. Na+/H+ antiporters have been suggested to play important roles in salt tolerance in plants. Here, we isolated AgNHX1 a vacuolar Na+/H+ antiporter from a halophytic species Atriplex gmelini and introduced it into fig (Ficus carica L.) cv. Black Mission via Agrobacterium-mediated transformation. Leaf discs explants of fig were co-cultivated for 2 days with Agrobacterium tumefaciens strain LBA 4404 harboring the binary vector pBI121 containing the AgNHX1 gene and the hpt selectable marker gene which encodes hygromycin phosphotransferase. Explants were cultured on MS medium containing 30 mg L−1 hygromycin, 3 % sucrose, 0.2 mg L−1 kinetin and 2.0 mg L−1 2,4-dichlorophenoxyacetic acid solidified with 2.5 g L−1 phytagel in darkness for callus formation. The calli were cultured on MS medium containing 2.0 mg L−1 zeatin riboside in combination with 0.4 mg L−1 indole acetic acid in the light for plant regeneration. Putative regenerated transformant shoots were confirmed by polymerase chain reaction (PCR) and Southern hybridization for the AgNHX1 gene. Reverse transcriptase polymerase chain reaction analysis indicated that the gene was highly expressed in transgenic plants, but the degree of this expression varied among transformants. Overexpression of the AgNHX1 gene conferred high tolerance to salt stress and transgenic fig plants overexpressing AgNHX1 developed normally under salinity conditions compared to those of non-transgenic plants. Salt treated transgenic plants contained high proline and K+ but less Na+ compared to non-transgenic control plants

    Phylogenetic and Expression Studies of Small GTP-Binding Proteins in Solanum lycopersicum Super Strain B

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    This investigation involved a comparative analysis of the small GTPase superfamily in S. lycopersicum super strain B compared to their analogues in leguminous and other non-leguminous species. The small GTPases superfamily members were recognized by tBLASTn searches. The sequences of amino acid were aligned using Clustal Omega and the analysis of phylogeny was performed with the MEGA7 package. Protein alignments were applied for all studied species. Three-dimensional models of RABA2, ROP9, and ROP10 from Solanum lycopersicum “Super strain B” were performed. The levels of mRNA of the Rab, Arf, Rop, and Ran subfamilies were detected in aerial tissues vs. roots. Significant divergences were found in the number of members and groups comprising each subfamily of the small GTPases and Glycine max had the highest count. High expression of Rab and Arf proteins was shown in the roots of legumes whilst in non-legume plants, the highest values were recorded in aerial tissues. S. lycopersicum super strain B had the highest expression of Rab and Arf proteins in its aerial tissues, which may indicate that diazotroph strains have supreme activities in the aerial tissues of strain B and act as associated N-fixing bacteria. The phylogenies of the small GTPase superfamily of the studied plants did not reveal asymmetric evolution of the Ra, Arf, Rop, and Ran subfamilies. Multiple sequence alignments derived from each of the Rab, Arf, and Rop proteins of S. lycopersicum super strain B showed a low frequency of substitutions in their domains. GTPases superfamily members have definite functions during infection, delivery, and maintenance of N2-fixing diazotroph but show some alterations in their function among S. lycopersicum super strain B, and other species.</jats:p

    Homo sapiens in Arabia by 85,000 years ago

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    Understanding the timing and character of Homo sapiens expansion out of Africa is critical for inferring the colonisation and admixture processes that underpin global population history. It has been argued that dispersal out of Africa had an early phase, particularly ~130-90 thousand years ago (ka), that only reached the East Mediterranean Levant, and a later phase, ~60-50 ka, that extended across the diverse environments of Eurasia to Sahul. However, recent findings from East Asia and Sahul challenge this model. Here we show that H. sapiens was in the Arabian Peninsula before 85 ka. We describe the Al Wusta-1 (AW-1) intermediate phalanx from the site of Al Wusta in the Nefud Desert, Saudi Arabia. AW-1 is the oldest directly dated fossil of our species outside Africa and the Levant. The palaeoenvironmental context of Al Wusta demonstrates that H. sapiens using Middle Palaeolithic stone tools dispersed into Arabia during a phase of increased precipitation driven by orbital forcing, in association with a primarily African fauna. A Bayesian model incorporating independent chronometric age estimates indicates a chronology for Al Wusta of ~95-86 ka, which we correlate with a humid episode in the later part of Marine Isotope Stage 5 known from various regional records. Al Wusta shows that early dispersals were more spatially and temporally extensive than previously thought. Early H. sapiens dispersals out of Africa were not limited to winter rainfall-fed Levantine Mediterranean woodlands immediately adjacent to Africa, but extended deep into the semi-arid grasslands of Arabia, facilitated by periods of enhanced monsoonal rainfall

    One fungus, which genes?: development and assessment of universal primers for potential secondary fungal DNA barcodes

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    The aim of this study was to assess potential candidate gene regions and corresponding universal primer pairs as secondary DNA barcodes for the fungal kingdom, additional to ITS rDNA as primary barcode. Amplification efficiencies of 14 (partially) universal primer pairs targeting eight genetic markers were tested across > 1 500 species (1 931 strains or specimens) and the outcomes of almost twenty thousand (19 577) polymerase chain reactions were evaluated. We tested several well-known primer pairs that amplify: i) sections of the nuclear ribosomal RNA gene large subunit (D1-D2 domains of 26/28S); ii) the complete internal transcribed spacer region (ITS1/2); iii) partial beta-tubulin II (TUB2); iv) gamma-actin (ACT); v) translation elongation factor 1-alpha (TEF1 alpha); and vi) the second largest subunit of RNA-polymerase II (partial RPB2, section 5-6). Their PCR efficiencies were compared with novel candidate primers corresponding to: i) the fungal-specific translation elongation factor 3 (TEF3); ii) a small ribosomal protein necessary for t-RNA docking; iii) the 60S L10 (L1) RP; iv) DNA topoisomerase I (TOPI); v) phosphoglycerate kinase (PGK); vi) hypothetical protein LNS2; and vii) alternative sections of TEF1 alpha. Results showed that several gene sections are accessible to universal primers (or primers universal for phyla) yielding a single PCR-product. Barcode gap and multi-dimensional scaling analyses revealed that some of the tested candidate markers have universal properties providing adequate infra- and inter-specific variation that make them attractive barcodes for species identification. Among these gene sections, a novel high fidelity primer pair for TEF1 alpha, already widely used as a phylogenetic marker in mycology, has potential as a supplementary DNA barcode with superior resolution to ITS. Both TOPI and PGK show promise for the Ascomycota, while TOPI and LNS2 are attractive for the Pucciniomycotina, for which universal primers for ribosomal subunits often fail

    Effects of methylphenidate on attention in Wistar rats treated with the neurotoxin N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP4)

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    The aim of this study was to assess the effects of the neurotoxin N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP4) on attention in rats as measured using the 5-choice-serial-reaction-time task (5CSRTT) and to investigate whether methylphenidate has effects on DSP4-treated rats. Methylphenidate is a noradrenaline and dopamine reuptake inhibitor and commonly used in the pharmacological treatment of individuals with attention deficit/hyperactivity disorder (ADHD). Wistar rats were trained in the 5CSRTT and treated with one of three doses of DSP4 or saline. Following the DSP4 treatment rats were injected with three doses of methylphenidate or saline and again tested in the 5CSRTT. The treatment with DSP4 caused a significant decline of performance in the number of correct responses and a decrease in response accuracy. A reduction in activity could also be observed. Whether or not the cognitive impairments are due to attention deficits or changes in explorative behaviour or activity remains to be investigated. The treatment with methylphenidate had no beneficial effect on the rats’ performance regardless of the DSP4 treatment. In the group without DSP4 treatment, methylphenidate led to a reduction in response accuracy and bidirectional effects in regard to parameters related to attention. These findings support the role of noradrenaline in modulating attention and call for further investigations concerning the effects of methylphenidate on attentional processes in rats

    Metagenomic analysis of fungal taxa inhabiting Mecca region, Saudi Arabia

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    AbstractThe data presented contains the sequences of fungal Internal Transcribed Spacer (ITS) and 18S rRNA gene from a metagenome of the Mecca region, Saudi Arabia. Sequences were amplified using fungal specific primers, which amplified the amplicon aligned between the 18S and 28S rRNA genes. A total of 460 fungal species belonging to 133 genera, 58 families, 33 orders, 13 classes and 4 phyla were identified in four contrasting locations. The raw sequencing data used to perform this analysis along with FASTQ file are located in the NCBI Sequence Read Archive (SRA) under accession numbers: SRR3150823, SRR3144873, SRR3150825 and SRR3150846

    Monumental landscapes of the Holocene humid period in Northern Arabia: The mustatil phenomenon

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    Between 10 and six thousand years ago the Arabian Peninsula saw the most recent of the ‘Green Arabia’ periods, when increased rainfall transformed this generally arid region. The transition to the Neolithic in Arabia occurred during this period of climatic amelioration. Various forms of stone structures are abundant in northern Arabia, and it has been speculated that some of these dated to the Neolithic, but there has been little research on their character and chronology. Here we report a study of 104 ‘mustatil’ stone structures from the southern margins of the Nefud Desert in northern Arabia. We provide the first chronometric age estimate for this type of structure – a radiocarbon date of ca. 5000 BC – and describe their landscape positions, architecture and associated material culture and faunal remains. The structure we have dated is the oldest large-scale stone structure known from the Arabian Peninsula. The mustatil phenomenon represents a remarkable development of monumental architecture, as hundreds of these structures were built in northwest Arabia. This ‘monumental landscape’ represents one of the earliest large-scale forms of monumental stone structure construction anywhere in the world. Further research is needed to understand the function of these structures, but we hypothesise that they were related to rituals in the context of the adoption of pastoralism and resulting territoriality in the challenging environments of northern Arabia
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