42 research outputs found

    Comparison of a Biometric Method with Clipping and Weighing Method for Estimating the Yield of \u3cem\u3eArtemisia sieberi\u3c/em\u3e (Case Study Zarand-e-Save Region)

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    Forage production is a most important vegetation attribute in rangeland analysis and evaluation and use in management practices. Artemisia sieberi covered about 47% of the rangeland area in Iran and scientists need to know the best method for analysis and evaluation of this species. Clipping and weighing has high precision, but this method is time-consuming and expensive and alternative methods are required. Russian scientists developed a biometric method based on plant dimensions and suggest this method for rangelands in the Middle East (discussed by Dianati, 2003). In America, Muray (1982) used plant dimensions for yield estimation and regression models for estimating production. This method required the selection of a lot of individual plants for each species to draw curves and estimate forage production. The critical stage of this method is the determination of the relationship between plant dimensions and yield. The research showed that in A. sieberi the best relationship with yield is from height (H) and the sum of diameters (D1 +D2). This relationship should be calculated separately for each species. In this study this method was tested with the Artemisia type in Iran

    The Spread of Tomato Yellow Leaf Curl Virus from the Middle East to the World

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    The ongoing global spread of Tomato yellow leaf curl virus (TYLCV; Genus Begomovirus, Family Geminiviridae) represents a serious looming threat to tomato production in all temperate parts of the world. Whereas determining where and when TYLCV movements have occurred could help curtail its spread and prevent future movements of related viruses, determining the consequences of past TYLCV movements could reveal the ecological and economic risks associated with similar viral invasions. Towards this end we applied Bayesian phylogeographic inference and recombination analyses to available TYLCV sequences (including those of 15 new Iranian full TYLCV genomes) and reconstructed a plausible history of TYLCV's diversification and movements throughout the world. In agreement with historical accounts, our results suggest that the first TYLCVs most probably arose somewhere in the Middle East between the 1930s and 1950s (with 95% highest probability density intervals 1905–1972) and that the global spread of TYLCV only began in the 1980s after the evolution of the TYLCV-Mld and -IL strains. Despite the global distribution of TYLCV we found no convincing evidence anywhere other than the Middle East and the Western Mediterranean of epidemiologically relevant TYLCV variants arising through recombination. Although the region around Iran is both the center of present day TYLCV diversity and the site of the most intensive ongoing TYLCV evolution, the evidence indicates that the region is epidemiologically isolated, which suggests that novel TYLCV variants found there are probably not direct global threats. We instead identify the Mediterranean basin as the main launch-pad of global TYLCV movements

    Role of oxidative stress and antioxidant therapy in acute and chronic phases of sulfur mustard injuries: a review

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    Sulfur mustard (SM) is a chemical compound that preferentially targets ocular, cutaneous and pulmonary tissues. Although pathologic effect of SM has been extensively considered, molecular and cellular mechanism of its toxicity, especially at the chronic phase of injury is not well-understood. Excessive production of reactive oxygen species (ROS) and oxidative stress (OS) appears to be involved in SM-induced injuries. SM may trigger several molecular and cellular pathways linked to OS and inflammation that can subsequently result in cell death and apoptosis. At the acute phase of injury, SM can enhance ROS production and OS by reducing the activity of antioxidants, depletion of intercellular glutathione (GSH), decreasing the productivity of GSH-dependent antioxidants, mitochondrial deficiency, accumulation of leukocytes and pro-inflammatory cytokines. Overexpression of ROS producing enzymes and down-regulation of antioxidant enzymes are probably the major events by which SM leads to OS at the chronic phase of injury. Therefore, antioxidant therapy with potent antioxidants such as N-acetylcysteine and curcumin may be helpful to mitigate SM-induced OS damages. This review aims to discuss the proposed cellular and molecular mechanisms of acute and delayed SM toxicity, the importance of OS and mechanisms by which SM increases OS either at the acute or chronic phases of injuries along with research on antioxidant therapy as a suitable antidote
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