Sublethal effects of spirodiclofen,abamectin and pyridaben on life-history traits and life-table parameters of two-spotted spider mite, <Emphasis Type="Italic">Tetranychus urticae</Emphasis> (Acari: Tetranychidae)

Tuckerella japonica Ehara (Acari: Tetranychoidea: Tuckerellidae) was found on stems of seedling plants of Camellia sinensis (L.) O. Kuntze (Theaceae) in the continental USA. This mite is able to pierce exposed green periderm tissue with its paired stylets on 1- to 3- or 4-year-old stems where the outer bark had split longitudinally. The mite was not found on branches older than 3 or 4 years, where splitting diminished and, eventually, a uniform covering of bark was formed. The mouthparts of T. japonica were examined under scanning electron microscopy and their external morphology was compared with known Tetranychoidea. There were usually one or two feeding holes in an area where the female subsequently deposited one or more eggs. Females were observed defending the areas where their eggs and/or young occurred. This behavior along with potentially limited access to exposed periderm or availability of shoots in the rows of plants may restrict higher populations of T. japonica from becoming established. The potential of T. japonica as an economic pest remains unknown at this time.     

Increasing frost risk associated with advanced citrus flowering dates in Kerman and Shiraz,Iran: 1960–2010

Flowering dates and the timing of late season frost are both driven by local ambient temperatures. However, under climatic warming observed over the past century, it remains uncertain how such impacts affect frost risk associated with plant phenophase shifts. Any increase in frost frequency or severity has the potential to damage flowers and their resultant yields and, in more extreme cases, the survival of the plant. An accurate assessment of the relationship between the timing of last frost events and phenological shifts associated with warmer climate is thus imperative. We investigate spring advances in citrus flowering dates (orange, tangerine, sweet lemon, sour lemon and sour orange) for Kerman and Shiraz, Iran from 1960 to 2010. These cities have experienced increases in both T _max and T _min, advances in peak flowering dates and changes in last frost dates over the study period. Based on daily instrumental climate records, the last frost dates for each year are compared with the peak flowering dates. For both cities, the rate of last frost advance lags behind the phenological advance, thus increasing frost risk. Increased frost risk will likely have considerable direct impacts on crop yields and on the associated capacity to adapt, given future climatic uncertainty.     

Particulate matter and bacteria characteristics of the Middle East Dust (MED) storms over Ahvaz,Iran

The Middle East Dust storms have greatly affected the south and west parts of Iran during the last decade. The main purpose of this study was to examine and compare culturable airborne bacteria concentration in particulate matter (PM) during normal, semi-dust, and dust event days in different places and seasons in Ahvaz from November 2011 to May 2012. Sampling was performed every 6 days and on dust event days at different sampling stations. The overall mean concentrations of PM₁₀, PM_2.5, and PM₁ for the entire study period were 598.92, 114.8, and 34.5 μg/m³, respectively. The PM concentrations during the dust event days were much higher than normal and semi-dust event days. The highest mean PM concentrations were observed in March 2011. The low PM_2.5/PM₁₀ ratios indicate that these PM are mostly originating from natural sources such as dust storms. The overall mean concentration of total bacteria during the study period was 620.6 CFU/m³. The greatest bacterial concentrations were observed during dust event days and at areas with high traffic and more human activities compared with normal days and greener areas. The percentage of gram-positive bacteria was significantly higher than that during the study period (89 vs 11 %). During this study, 26 genera of culturable bacteria were identified from all the sampling stations. The most dominant genera in all sampling stations were Streptomyces, Bacillus, Kocuria, Corynebacterium, and Paenibacillus. The results also showed that there were positive correlations between PM and bacterial concentrations during the study period (p < 0.05).     

Cloning,expression, purification,and characterization of recombinant flagellin isolated from <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis>

Pseudomonas aeruginosa as an opportunistic pathogen causes lethal infections in immunocompromised individuals. This bacterium possesses a polar flagellum made up of flagellin subunits. Flagella have important roles in motility, chemotaxis, and establishment of P. aeruginosa in acute phase of infections. Isolation, cloning, and expression of flagellin were aimed at in this study. Flagellin gene (fliC) of P. aeruginosa strain 8821M was isolated by PCR and cloned into a pET expression vector. The recombinant flagellin (46 kDa) was overexpressed as inclusion bodies (IBs). IBs were solubilized in guanidine hydrochloride (GuHCl) followed by affinity-purification and renatured using Ni²⁺-Sepharose resin. Recombinant flagellins reacted with the serum from a rabbit previously immunized with native flagellin. In addition, polyclonal antiserum raised against the recombinant flagellin was shown to significantly inhibit the cell motility of P. aeruginosa strain 8821M in vitro.     

Chitinolytic and antifungal activity of a <Emphasis Type="Italic">Bacillus pumilus</Emphasis> chitinase expressed in <Emphasis Type="Italic">Arabidopsis</Emphasis>

The Bacillus pumilus SG2 chitinase gene (ChiS) and its truncated form lacking chitin binding (ChBD) and fibronectin type III (FnIII) domains were transformed to Arabidopsis plants and the expression, functionality and antifungal activity of the recombinant proteins were investigated. Results showed that while the two enzyme forms showed almost equal hydrolytic activity toward colloidal chitin, they exhibited a significant difference in antifungal activity. Recombinant ChiS in plant protein extracts displayed a high inhibitory effect on spore germination and radial growth of hyphae in Alternaria brassicicola, Fusarium graminearum and Botrytis cinerea, while the activity of the truncated enzyme was strongly abolished. These findings demonstrate that ChBD and FnIII domains are not necessary for hydrolysis of colloidal chitin but play an important role in hydrolysis of chitin–glucan complex of fungal cell walls. Twenty microgram aliquots of protein extracts from ChiS transgenic lines displayed strong antifungal activity causing up to 80% decrease in fungal spore germination. This is the first report of a Bacillus pumilus chitinase expressed in plant system.     

Bioactivity of aviprin and aviprin-3″-<Emphasis Type="Italic">O</Emphasis>-glucoside,two linear furanocoumarins from Apiaceae

Furanocoumarins are well-known natural products that occur in the most evolved genera of Apiaceae family. This compounds were found to have cytotoxic, phytotoxic, photosensitizing, insecticidal, antibacterial and high antifungal effects. Aviprin is considered as a linear furanocoumarin substituted at C8 with an oxygenated prenyl residue. In this study we found that aviprin is a bioactive compound that exhibits high antibacterial, antifungal and phytotoxic activity. The compound stunted the germination of lettuce seeds with IC₅₀ value of 0.270 mg/ml. The compound also inhibited the mycelia growth of Sclerotinia sclerotiorum. Aviprin indicated antibacterial activity against tested gram negative and positive bacteria with inhibition zone of 19–23.5 mm. Our results shown that aviprin can play an allelopatic role for plant.     

Production of nitric oxide by murine macrophages induced by lipophosphoglycan of Leishmania major

Protozoan parasites of the genus Leishmania cause a number of important human diseases. One of the key determinants of parasite infectivity and survival is the surface glycoconjugate lipophosphoglycan (LPG). In addition, LPG is shown to be useful as a transmission blocking vaccine. Since culture supernatant of parasite promastigotes is a good source of LPG, we made attempts to characterize functions of the culture supernatant, and membrane LPG isolated from metacyclic promastigotes of Leishmania major. The purification scheme included anion-exchange chromatography, hydrophobic interaction chromatography and cold methanol precipitation. The purity of supernatant LPG (sLPG) and membrane LPG (mLPG) was determined by SDS-PAGE and thin layer chromatography. The effect of mLPG and sLPG on nitric oxide (NO) production by murine macrophages cell line (J774.1A) was studied. Both sLPG and mLPG induced NO production in a dose dependent manner but sLPG induced significantly higher amount of NO than mLPG. Our results show that sLPG is able to promote NO production by murine macrophages.     

Soils selenium level and esophageal cancer: An ecological study in a high risk area for esophageal cancer

ProjectGolestan province, located in northeast of Iran, has been known as a high risk area for esophageal cancer (EC). This study was conducted to assess the relationship between soils selenium (Se) level and development of EC in this region.ProceduresIn this ecological study, 135 blocks were identified in Golestan province based on geographical altitude and longitude on the map. One soil sample was collected from the center of each block. Then we investigated Se concentration in soil samples by flame atomic absorption spectrometry. Statistical analysis was performed by the Pearson correlation test and Student t-tests. P-values of less than 0.05 were considered as significant.ResultsThe mean±SD of soils Se level in Golestan province was 3.7±1.61 mg/kg. There was a positive correlation between soils Se level and EC rates in this area (P=0.03) (Pearson correlation coefficient=0.19). Soils Se concentration was significantly higher in high (4.13 mg/kg) than in the low (3.39 mg/kg) EC rate areas (P=0.01).ConclusionsWe found high soils Se concentration and a significant positive relationship between soils Se level and EC rate in Golestan province of Iran. So, high soils Se level may play a possible role in developing EC in this area, specifically in Turkmensahra (very high EC rates).