AXR1-ECR1-dependent conjugation of RUB1 to the Arabidopsis Cullin AtCUL1 is required for auxin response

Mutations in the AXR1 gene result in a reduction in auxin response and diverse defects in auxin-regulated growth and development. In a previous study, we showed that AXR1 forms a heterodimer with the ECR1 protein. This enzyme activates the ubiquitin-related protein RUB1 in vitro. Furthermore, we showed that the Skp1-Cul1/Cdc53-F-box (SCF) subunit AtCUL1 is modified by RUB1 in vivo. In this report, we demonstrate that the formation of RUB-AtCUL1 is dependent on AXR1 and ECR1 in vivo. The expression of AXR1 and ECR1 is restricted to zones of active cell division and cell elongation, consistent with their role in growth regulation. These results provide strong support for a model in which RUB conjugation of AtCUL1 affects the function of SCF E3s that are required for auxin response.     

Bioassay evaluation of the entomopathogenic fungus,Lecanicillium longisporum (Petch) Zare & Gams against egg and nymphs of Trialeurodes vaporariorum Westwood in laboratory conditions

Abstract

This study was carried out to determine the lethality of the entomopathogenic fungus, Lecanicillium longisporum on eggs, young and old nymphs of the greenhouse whitefly, Trialeurodes vaporariorum. Mortality percentage was significantly differed based on stage of T. vaporariorum and conidial concentrations of L. longisporum. Average of the infection level to insect was very low particularly in egg with only 9.81%, even with higher conidial concentrations (1×10⁷ conidia mL^-1). Whereas, it was higher in 1^st and 2^nd instar (46.56%) and 3^rd and 4^th instars (37.21%). Three parameters were assessed with T. vaporariorum eggs, namely; egg infection, egg hatchability and crawlers emergence. Egg mortality percentages averaged 3.56, 7.14, 9.64, 16.42 and 20.35% with fungal concentrations of 1×10³, 1×10⁴, 1×10⁵, 1×10⁶ and 1×10⁷ conidia mL^-1, respectively. Daily infection percentages were varied depend upon the conidia concentration where the highest infection rate of eggs was occurred with 1×10⁷. Egg hatch was very high and the mortality among the emerged crawlers was neglectable compared with the control. Efficiency of L. longisporum on whitefly nymphs also was varied based on the insect instar and fungal concentration. Mortality percentages were obviously higher in young nymphs (1^st and 2^nd instars) than in older ones (3^rd and 4^th instars). The results indicated that nymphs were highly susceptible to fungal treatment compared with eggs.     

Production and preparation of hyperimmune bovine colostrum for passive immunotherapy of cryptosporidiosis.

Pregnant cows were immunized to produce hyperimmune bovine colostrum (HBC) by intramuscular injection or intramammary infusion (TI) followed by 3 successive TI boosters with Cryptosporidium parvum (Cp) oocyst antigen mixed with Freund's (F) or Ribi (R) adjuvant. Control cows received no Cp. Colostrum from all cows was skimmed of butterfat and tested for specific anti-Cp immunoglobulin isotypes by ELISA. The HBC from Cp-F and Cp-R immunized cows had IgG1 titers exceeding 1:400,000 and 1:800,000, respectively. Some HBC from Cp-F immunized cows was freeze-dried to facilitate storage and some were irradiated at 42.5 kGy to kill potentially contaminating pathogens. Freeze-drying, but not irradiation, reduced IgG1 titers by only one dilution. Neither treatment affected Western blot banding patterns.     

Retina expresses microsomal triglyceride transfer protein: implications for age-related maculopathy

The principal extracellular lesions of age-related maculopathy (ARM), the leading cause of vision loss in the elderly, involve Bruch's membrane (BrM), a thin vascular intima between the retinal pigment epithelium (RPE) and its blood supply. With age, 80-100 nm solid particles containing esterified cholesterol (EC) accumulate in normal BrM, and apolipoprotein B (apoB) immunoreactivity is detectable in BrM- and ARM-associated lesions. Yet little evidence indicates that increased plasma cholesterol is a risk factor for ARM. To determine if RPE is capable of assembling its own apoB-containing lipoprotein, we examined RPE for the expression of microsomal triglyceride transfer protein (MTP), which is required for this process. Consistent with previous evidence for apoB expression, MTP is expressed in RPE, the ARPE-19 cell line, and, unexpectedly, retinal ganglion cells, which are neurons of the central nervous system. De novo synthesis and secretion of neutral lipid by ARPE-19 was supported by high levels of radiolabeled EC and triglyceride in medium after supplementation with oleate. Lipoprotein assembly and secretion is implicated as a constitutive retinal function and a plausible candidate mechanism involved in forming extracellular cholesterol-containing lesions in ARM. The pigmentary retinopathy and neuropathy of abetalipoproteinemia (Mendelian Inheritance of Man 200100; Bassen-Kornzwieg disease), which is caused by mutations in the MTP gene, may involve loss of function at the retina.     

Cytochrome c(553), a small heme protein that lacks misligation in its unfolded state, folds with rapid two-state kinetics

Cytochrome c(553) (cyt c(553)) from Desulfovibrio vulgaris is a small helical heme protein that displays apparent two-state equilibrium-unfolding behavior. The covalently attached heme is low-spin, ligated by Met and His residues, in the native state but becomes high-spin upon unfolding at pH 7. Here, we show that in contrast to other c-type heme proteins, where misligations in the unfolded states are prominent, cyt c(553) refolding kinetics at pH 7 proceeds rapidly without detectable intermediates. The extrapolated folding rate constant in water for oxidized cyt c(553) matches exactly that predicted from the cyt c(553) native-state topology: 5300 s(-1 )(experimental) versus 5020 s(-1) (predicted). We therefore conclude that the presence of the oxidized cofactor does not affect the intrinsic formation speed of the cyt c(553 )structural motif.     

Effect of β-Cyclodextrin Nanoparticle on Biosynthesis of Ocimum basilicum L. Monoterpenes,Sesquiterpenes in a Concentration-Dependent Behavior

Russian Journal of Plant Physiology - Engineered nanoparticles can alter the metabolism pathways and the profiling of metabolites in plants. In this study, we prepared the β-cyclodextrin...     

Developmental rate ofOpius concolor (HYM.: Braconidae) at various constant temperatures

Opius concolor Szépligeti is a parasite ofBactrocera oleae (Gmelin) and other Tephritid flies. Its development rate was studied with the Sharpe-DeMichele mathematical model, modified by Schoofieldet al. (1981), using the S.A.S. program elaborated by Wagneret al. (1984). This program chose a four parameter poikilotherm model with high temperatures inhibition. Duration of parasitoid development at seven constant temperatures ranged from 14.6±1.7 days at 28°C (males), to 77.2±5.5 days at 15°C (females). Male development was consistently found to be shorter than that of females. Low development threshold and degree-days needed to complete total development were determined with the “Regression Line” and “Thermal Summation” methods. Values (cumulated for both sexes) were found to be respectively 11.7°C and 11.8°C (low threshold), 255.9 and 251.9±16.8 days (thermal constant). Considerations on the possibility of establishingOpius concolor in northern and central Italian regions are discussed.     

Immunogold labeling of stages of Cryptosporidium parvum recognized by immunoglobulins in hyperimmune bovine colostrum

Ultrathin sections of mouse ileum infected with Cryptosporidium parvum were stained by immunogold techniques. Sections first were stained with polyvalent antibodies in whey from hyperimmune bovine colostrum (HBC), then stained by secondary antibodies in rabbit antibovine IgA, IgM, IgG1, and IgG2, and lastly labeled by goat anti-rabbit gold conjugate. Examination of the immunostained specimens by electron microscopy revealed that each bovine immunoglobulin isotype in the whey recognized antigens in meronts, merozoites, microgametocytes, microgametes, and macrogamonts. Based on these findings it is hypothesized that antigens in all stages of C. parvum provide targets of opportunity for the antiparasitic activity of HBC whey antibodies thereby accounting for its efficacy as an immunotherapeutic agent.