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High Populations (high + population)
Terms modified by High Populations Selected AbstractsTospoviruses infecting vegetable crops in IsraelEPPO BULLETIN, Issue 2 2000A. Gera Symptoms of vein clearing, stem necrosis, curling, necrotic spots and rings on the leaves associated with infection by tomato spotted wilt tospovirus (TSWV) were documented among vegetable crops growing in commercial glasshouses and open fields in Israel. Plants exhibiting symptoms were collected, from 1994-01 to 1998-12. Among cultivated vegetable crops analysed for TSWV by ELISA, the following plants were found to be infected: tomato, capsicum, aubergine, lettuce, cabbage and cucumber. These incidences of the virus were all correlated with the occurrence in high population of Frankliniella occidentalis. Transmission of the virus from infected Datura stramonium to Petunia leaf discs, by F. occidentalis, was up to 26%. TSWV antigens were readily detected by ELISA in seeds harvested from naturally infected vegetable crops. However, we failed to show virus transmission to the progeny plants. Iris yellow spot tospovirus (IYSV) was detected in onion. High incidence of the disease was associated with large populations of Thrips tabaci. [source] Role of ocular pigment epithelial cells in regional ocular immunityACTA OPHTHALMOLOGICA, Issue 2008S SUGITA Purpose To whether soluble factors by retinal pigment epithelial cells (RPE) promote the generation of T regulatory cells in vitro. Methods Primary cultured RPE cells were established from normal C57BL/6 mice. T cells were co-cultured with RPE, x-irradiated, and used as regulators (RPE Treg cells). Target bystander T cells were established from normal splenic T cells with anti-CD3 antibodies. T-cell activation was assessed for proliferation by [3H],thymidine incorporation. Expression of cytotoxic T lymphocyte antigen-2, (CTLA-2,) and cathepsin L on RPE and T cells was evaluated with oligonucleotide microarray, RT-PCR, immune staining, western blots and flow cytometry. Recombinant mouse CTLA-2, and anti-mouse CTLA-2, abs were used for the assay. For induction of experimental autoimmune uveitis (EAU), mice were immunized with interphotoreceptor retinoid-binding protein peptide emulsified in complete Freund's adjuvant. Results RPE converted CD4+ T cells into Treg cells by producing and secreting CTLA-2,, a cathepsin L inhibitor. CTLA-2, secreted by RPE cells selectively inhibited cathepsin L in the T cells and the cathepsin L-lacking T cells exhibited Treg phenotype, i.e. expression of Foxp3 and production of transforming growth factor beta (TGF,). CTLA-2, enhanced their production of active forms of TGF,. In addition, CD4+ T cells from EAU-induced cathepsin L knockout (KO) donors contained high population of Foxp3+ T cells and EAU in cathepsin L KO mice was significantly less than those in wild type mice. Furthermore, treatment with recombinant CTLA-2, significantly suppressed EAU. Conclusion These results indicate that immunosuppressive factors derived from RPE participate in the establishment of immune regulation in the posterior segment of the eye. [source] Seasonal distribution and species composition of daytime biting mosquitoesENTOMOLOGICAL RESEARCH, Issue 2 2009Waseem AKRAM Abstract Adults and immatures of Aedes mosquito populations were collected at temperatures between 40 and 44°C (summer), while larvae were collected at 0°C (winter). Major mosquito activities were observed from February to mid-December at various collection sites that yielded high populations of Aedes spp. from May to September, and high populations of Culex spp. and Anopheles spp. from March to September. In June to July, mosquito activity was suspended because the relative humidity was high (70%); a result of the monsoon rains. In August, with temperature ranging from 38 to 42°C, the populations of Culex, Anopheles and Aedes began to increase (36.8, 32.1 and 26.3%, respectively). Population estimates (through standard prototype Centers for Disease Control (CDC) and Biogents (BG)-sentinel) and species composition of Aedes in forest habitats indicated a rapid increase in the populations of Ae. albopictus (52.3%), Ae. aegypti (19.1%) and Ae. vittatus (28.5%) following the rainy season in July. Areas positive for Ae. albopictus had identical population levels and distribution ranges of Ae. vittatus, however, there were no Ae. aegypti in Ae. albopictus areas from August to September. The population level, seasonal distribution, habitat and areas of adult activity marked by global positioning system (GPS) coordinates are being used for reference and for species composition data of Anopheles spp. (2), Culex spp. (10) and Aedes spp. (5) in addition to associated temperature, relative humidity and physico-chemical factors of larval habitat. Global meteorological changes have caused an expansion of the active period, leading to the mosquito's possibility of being a vector of disease increasing, resulting in the spread of dengue fever. [source] BEHAVIOR OF AVIRULENT YERSINIA PESTIS IN LIQUID WHOLE EGG AS AFFECTED BY STORAGE TEMPERATURE, ANTIMICROBIALS AND THERMAL PASTEURIZATIONJOURNAL OF FOOD SAFETY, Issue 3 2010JOSHUA B. GURTLER ABSTRACT Yersinia spp. are psychrotrophic bacteria capable of growth at temperatures as low as ,2C, known to contaminate shell eggs and liquid eggs in the U.S.A. and South America. A study was performed to determine the thermal sensitivity of avirulent Yersinia pestis in liquid whole egg (LWE), evaluate the growth pattern of the bacterium in LWE at temperatures of 4,22C and assess the ability of 10 antimicrobial compounds to inhibit the growth of attenuated Y. pestis in LWE. The estimated decimal reduction values of avirulent Y. pestis in LWE at 54C (D54) were 1.39,1.58 min, and D60 values were 13.8 and 11.4 s by the addition of 0 and 965 IU of nisin (MP Biomedicals, LLC, Solon, OH), respectively. Low molecular weight chitosan (0.5%) and an activated lactoperoxidase system (2.18 U/mL) were ineffective at inhibiting growth of Y. pestis, while 500 IU/mL of nisin inhibited populations by up to 1 log cfu/mL at 4, 10 and 15C when compared with the control. Allyl isothiocyanate, diacetyl, diethyl dicarbonate, ethylenediaminetetraacetic acid, methylparaben, monolaurin and benzoyl peroxide inhibited the growth of attenuated Y. pestis when added at high levels. PRACTICAL APPLICATIONS The genus Yersinia does not currently pose a problem in pasteurized liquid egg products, although it has been isolated from eggs in the U.S.A. and Argentina. Yersiniae, which are psychrotrophic bacteria, can grow at temperatures as low as ,2C; therefore, incidental or intentional contamination of liquid whole egg (LWE) with Yersinia spp. could result in multiplication to high populations, even when stored under refrigeration (ca. 4C). We have shown that avirulent Yersinia pestis is able to multiply to populations of >2, 5 and 8 log cfu/mL in LWE at 4C within 6, 14 and 26 days, respectively. This study provides information that will be helpful in determining thermal and nonthermal means of controlling yersiniae in LWE products. [source] Teachers' perceptions of policy influences on science instruction with culturally and linguistically diverse elementary studentsJOURNAL OF RESEARCH IN SCIENCE TEACHING, Issue 5 2007Annis Shaver Abstract This study asked elementary school teachers how educational policies affected their science instruction with a majority of English language learners. The study employed a questionnaire followed by focus group interviews with 43 third and fourth grade teachers from six elementary schools in a large urban school district with high populations of English language learners in the southeastern United States. Results indicate that teachers' opinions concerning all areas of policy evolved as the state enforced stronger measures of accountability during the 2-year period of the study. Although relatively positive regarding standards, their opinions became increasingly negative regarding statewide assessment, and even more so toward accountability measured by reading, writing, and mathematics. The results suggest that it is important to understand how teachers perceive the influence of policies, particularly those relating to English language learners, as science accountability becomes more imminent across the states. © 2007 Wiley Periodicals, Inc. J Res Sci Teach 44: 725,746, 2007 [source] DspA/E, a type III effector of Erwinia amylovora, is required for early rapid growth in Nicotiana benthamiana and causes NbSGT1-dependent cell deathMOLECULAR PLANT PATHOLOGY, Issue 3 2007CHANG-SIK OH SUMMARY DspA/E is a pathogenicity factor of Erwinia amylovora that is translocated into the plant cell cytoplasm through an Hrp type III secretion system. Transient expression of dspA/E in Nicotiana benthamiana or yeast induced cell death, as it does in N. tabacum and apple as described previously. DspA/E-induced cell death in N. benthamiana was not inhibited by coexpression of AvrPtoB of Pseudomonas syringae pv. tomato, which inhibits programmed cell death (PCD) induced by several other elicitors in plants. Silencing of NbSGT1, the expression of which is required for PCD mediated by several resistance proteins of plants, prevented DspA/E-induced cell death in N. benthamiana. However, silencing of NbRAR1, or two MAP kinase kinase genes, which are required for PCD associated with many resistance genes in plants, did not prevent cell death induced by DspA/E. Silencing of NbSGT1 also compromised non-host resistance against E. amylovora. E. amylovora grew rapidly within the first 24 h after infiltration in N. benthamiana, and DspA/E was required for this early rapid growth. However, bacterial cell numbers decreased after 24 h in TRV-vector-transformed plants, whereas a dspA/E mutant strain grew to high populations in NbSGT1 -silenced plants. Our results indicate that DspA/E enhances virulence of E. amylovora in N. benthamiana, but the bacteria are then recognized by the plant, resulting in PCD and death of bacterial cells or restriction of bacterial cell growth. [source] | ||||||||||