Enterotoxigenic Escherichia coli (ETEC) colonize the intestine and adhere to the epithelium by means of different host specific colonization factors (CFs). Colonizing ETEC produce one or both of two enterotoxins; the heat stable (ST) and heat labile (LT) toxins which are both able to cause diarrhoea. The regulation of virulence genes in ETEC during infection of the human intestine is mainly unknown. In this study we analysed the level of mRNA expression of estA, coding for ST, and eltB, coding for the B subunit of LT, during human infection. The expressions of the toxins in ETEC strains expressing both ST and LT were investigated in bacteria isolated directly from patient stool without sub-culturing, (in vivo) and compared to the expression pattern of the corresponding ST/LT strains grown in liquid broth (in vitro) by quantitative competitive RT-PCR using fluorescent primers. We found that estA and eltB are expressed in the in vivo samples but no significant up-or down regulation of the expression levels of either estA or eltB could be determined in vivo as compared to in vitro.
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http://dx.doi.org/10.1016/j.micinf.2006.08.011 | DOI Listing |
Materials (Basel)
December 2024
National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001, China.
In this study, a (TiB + TiC + YO)/α-Ti composite was prepared by induction skull melting to investigate its creep behavior and microstructure evolution under different temperatures and stresses. The results show that the microstructure of the composite in the as-cast state is a basket-weave structure, and the main phase composition is α lamella, containing a small amount of β phase and equiaxed α phase. The creep life of the composite decreases significantly when the temperature is increased from 650 °C to 700 °C, and the steady-state creep rate is increased by 1 to 2 orders of magnitude.
View Article and Find Full Text PDFPlants (Basel)
January 2025
Earth and Life Institute-Agronomy, Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium.
As a result of climate change, temperate regions are facing the simultaneous increase in water and heat stress. These changes may affect the interactions between plants and pollinators, which will have an impact on entomophilous crop yields. Here, we investigated the consequences of high temperatures and water stress on plant growth, floral biology, flower-reward production, and insect visitation of five varieties of common buckwheat (), an entomophilous crop of growing interest for sustainable agriculture.
View Article and Find Full Text PDFMolecules
January 2025
FEQx Lab, Department of Chemical Engineering, University of Vigo, 36310 Vigo, Spain.
Polyphenolic compounds are key elements in sectors such as pharmaceutics, cosmetics and food; thus, their physicochemical characterization is a vital task. In this work, the thermal behavior of seven polyphenols (-resveratrol, -polydatin, kaempferol, quercetin, myricetin, hesperidin, and (-)-epicatechin) was investigated with DSC (differential scanning calorimetry) and TGA (thermogravimetric analysis). Melting temperatures, enthalpies of fusion and decomposition temperatures were determined, and heat capacities were measured in the temperature range from 283.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China.
Stretchable electronics have significant applications in wearable applications. However, the extremely low thermal conductivity of elastic encapsulation hinders heat dissipation, leading to performance degradation. For instance, stretchable thermoelectric devices (TEDs) can be used for skin temperature regulation, but poor thermal management limits their cooling performance.
View Article and Find Full Text PDFProtoplasma
January 2025
Department of Turf Science and Engineering, College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China.
Creeping bentgrass (Agrostis stolonifera) is a cool-season perennial turfgrass and is frequently utilized in high-quality turf areas. However, a poor to moderate resistance to heat stress limits its promotion and utilization in transitional and worm climate zones. The objectives of the study were to assess the heat tolerance of 18 creeping bentgrass genotypes in the field and to further uncover differential mechanisms of heat tolerance between heat-tolerant and heat-sensitive genotypes.
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