The membrane-associated form of as1- casein interacts with cholesterol-rich detergent-resistant microdomains

Caseins, the main milk proteins, interact with colloidal calcium phosphate to form the casein micelle. The mesostructure of this supramolecular assembly markedly influences its nutritional and technological functionalities. However, its detailed molecular organization and the cellular mechanisms involved in its biogenesis have been only partially established. There is a growing body of evidence to support the concept that as1-casein takes center stage in casein micelle building and transport in the secretory pathway of mammary epithelial cells. Here we have investigated the membrane-associated form of as1-casein in rat mammary epithelial cells. Using metabolic labelling we show that as1-casein becomes associated with membranes at the level of the endoplasmic reticulum, with no subsequent increase at the level of the Golgi apparatus. From morphological and biochemical data, it appears that caseins are in a tight relationship with membranes throughout the secretory pathway. On the other hand, we have observed that the membrane-associated form of as1-casein co-purified with detergent-resistant membranes. It was poorly solubilised by Tween 20, partially insoluble in Lubrol WX, and substantially insoluble in Triton X-100. Finally, we found that cholesterol depletion results in the release of the membrane-associated form of as1-casein. These experiments reveal that the insolubility of as1-casein reflects its partial association with a cholesterolrich detergent-resistant microdomain. We propose that the membrane-associated form of as1-casein interacts with the lipid microdomain, or lipid raft, that forms within the membranes of the endoplasmic reticulum, for efficient forward transport and sorting in the secretory pathway of mammary epithelial cells

Nanodust detection near 1 AU from spectral analysis of Cassini/RPWS radio data

Nanodust grains of a few nanometer in size are produced near the Sun by collisional break-up of larger grains and picked-up by the magnetized solar wind. They have so far been detected at 1 AU by only the two STEREO spacecraft. Here we analyze the spectra measured by the radio and plasma wave instrument onboard Cassini during the cruise phase close to Earth orbit; they exhibit bursty signatures similar to those observed by the same instrument in association to nanodust stream impacts on Cassini near Jupiter. The observed wave level and spectral shape reveal impacts of nanoparticles at about 300 km/s, with an average flux compatible with that observed by the radio and plasma wave instrument onboard STEREO and with the interplanetary flux models

The nature of a self

The purpose of this thesis is to demonstrate just what kind of entity a self or person is (p. 1).KMBT_363Adobe Acrobat 9.54 Paper Capture Plug-i

Mass Loss, Destruction and Detection of Sun-grazing and -impacting Cometary Nuclei

[Abridged] Sun-grazing comets almost never re-emerge, but their sublimative destruction near the sun has only recently been observed directly, while chromospheric impacts have not yet been seen, nor impact theory developed. Employing simple analytic models to describe comet destruction near the Sun and to enable the estimation of observable signatures, we find analytic solutions for the mass as a function of distance from the Sun, for insolation sublimation, impact ablation and explosion. Sun-grazers are found to fall into three regimes based on initial mass and perihelion: sublimation-, ablation-, and explosion-dominated. Most sun-grazers are destroyed sublimatively, and our analytic results are similar to numerical models. Larger masses (>10^11g) with small perihelion (q<1.01Rsun) ablation dominates but results are sensitive to nucleus strength, Pc, and entry angle to the vertical, phi. Nuclei with initial mass >~10^10g (Pc/10^6 (dyne/cm^2) sec (phi))^3 are fully ablated before exploding, though the hot wake itself explodes. For most sun-impactors sec(phi)~1. For small perihelion the ablation regime applies to moderate masses ~10^13-16 g impactors unless Pc is very low. For higher masses, or smaller perihelia, nuclei reach higher densities where ram pressure causes catastrophic explosion. For perihelion 10^11 g nuclei are destroyed by ablation or explosion (depending on phi and Pc) in the chromosphere, producing flare-like events with cometary abundance spectra. For all plausible masses and physical parameters, nuclei are destroyed above the photosphere.Comment: 12 pages, 5 figures, Accepted A&

Conceptions of experiments in teaching mathematics and teaching physics in Vietnam

This article presents a part of the Inter-Tetra project. This study firstly reviews the literature on conceptions of experiments in didactics of math and didactics of physics to design questionnaires to survey the conceptions of experiments in teaching physics and teaching math in Vietnam. Thereafter, the survey has been conducted among the math and physics pedagogical students in the Hanoi National University of Education (HNUE). The results of the survey have revealed the similarities and differences of the concepts of an experiment in teaching math and physics. In addition, this study also discusses the causes and consequence of the similar and dissimilar concepts of experiments

Conceptions of experiments in teaching mathematics and teaching physics in Vietnam

This article presents a part of the Inter-Tetra project. This study firstly reviews the literature on conceptions of experiments in didactics of math and didactics of physics to design questionnaires to survey the conceptions of experiments in teaching physics and teaching math in Vietnam. Thereafter, the survey has been conducted among the math and physics pedagogical students in the Hanoi National University of Education (HNUE). The results of the survey have revealed the similarities and differences of the concepts of an experiment in teaching math and physics. In addition, this study also discusses the causes and consequence of the similar and dissimilar concepts of experiments

ẢNH HƯỞNG CỦA CHẾ PHẨM SINH HỌC CHỨA VI KHUẨN Pediococcus pentosaceus LÊN SINH TRƯỞNG, HIỆU QUẢ SỬ DỤNG THỨC ĂN VÀ ENZYME TIÊU HÓA CỦA CÁ DÌA (Siganus guttatus, Bloch 1787)

This study was conducted to evaluate the effects of Pediococcus pentacocceus supplemented-diets on growth rate, feed efficiency and digestive enzyme activity of rabbitfish (Siganus guttatus, Bloch 1787). Fingerlings (size of 4.63 ± 0.41 g) were fed with three P. pentacocceus supplemented-diets at different concentrations. Specifically, fish were fed diets supplemented with P. pentosaceus at concentration of 107 CFU/g (T1), 108 CFU/g (T2), 109 CFU/g (T3) and a control diet (CT) without P. pentosaceus supplementation. Each diet was performed on 3 replicates. After 60 days of culture, the results showed that diets supplemented with P. pentosaceus significantly improved the growth rate, feed efficiency and digestive enzyme activity of Siganus guttatus compared to the control. Growth parameters such as final weight (20.06 g), weight gain (331.96%) and growth rate (0.25 g/fish/day) were found in T2 and were significant differences compared to the other treatments (p &lt; 0.05). Similarly, digestive enzyme activities including amylase, lipase and protease were significantly increased in the group of fish fed with feed supplemented with P. pentosaceus compared to the control group. The results indicate that the supplementation of P. pentacocceus (specially, at a concentration of 108 CFU/g) into the diets notably improves the growth rate, feed efficiency, and digestive enzyme activity of rabbitfish.Nghiên cứu này nhằm đánh giá ảnh hưởng của việc bổ sung vi khuẩn Pediococcus pentacocceus vào thức ăn lên sinh trưởng, hiệu quả sử dụng thức ăn và hoạt tính enzyme tiêu hóa của cá dìa (Siganus guttatus, Bloch 1787). Cá giống (4,63 ± 0,41 g) được cho ăn 3 khẩu phần ăn có bổ sung vi khuẩn ở các mật độ khác nhau, bao gồm P. pentosacceus ở 107 CFU/g (T1), 108 CFU/g (T2), 109 CFU/g (T3) và một khẩu phần đối chứng (CT) không bổ sung P. pentosacceus. Mỗi khẩu phần được lặp lại 3 lần. Sau 60 ngày nuôi, kết quả cho thấy bổ sung P. pentosacceus cải thiện tốc độ sinh trưởng, hiệu quả sử dụng thức ăn và hoạt tính enzyme tiêu hóa của cá. Các chỉ tiêu sinh trưởng như khối lượng cuối (20,06 g), mức tăng khối lượng (331,96%) và tốc độ sinh trưởng (0,25 g/con/ngày) cao nhất được tìm thấy ở T2 và có sự khác biệt so với các nghiệm thức còn lại                         (p &lt; 0,05). Tương tự, hoạt tính enzyme tiêu hóa gồm amylase, lipase và protease có sự tăng lên ở nhóm cá được cho ăn thức ăn có bổ sung chế phẩm so với nhóm đối chứng. Kết quả nghiên cứu này khuyến khích bổ sung vi khuẩn P. pentosacceus (mật độ 108 CFU/g) vào thức ăn để nâng cao sinh trưởng, hiệu quả sử dụng thức ăn và hoạt tính enzyme tiêu hóa của cá dìa

Plasmodium falciparum metacaspase PfMCA-1 triggers a z-VAD-fmk inhibitable protease to promote cell death.

Activation of proteolytic cell death pathways may circumvent drug resistance in deadly protozoan parasites such as Plasmodium falciparum and Leishmania. To this end, it is important to define the cell death pathway(s) in parasites and thus characterize proteases such as metacaspases (MCA), which have been reported to induce cell death in plants and Leishmania parasites. We, therefore, investigated whether the cell death function of MCA is conserved in different protozoan parasite species such as Plasmodium falciparum and Leishmania major, focusing on the substrate specificity and functional role in cell survival as compared to Saccharomyces cerevisae. Our results show that, similarly to Leishmania, Plasmodium MCA exhibits a calcium-dependent, arginine-specific protease activity and its expression in yeast induced growth inhibition as well as an 82% increase in cell death under oxidative stress, a situation encountered by parasites during the host or when exposed to drugs such as artemisins. Furthermore, we show that MCA cell death pathways in both Plasmodium and Leishmania, involve a z-VAD-fmk inhibitable protease. Our data provide evidence that MCA from both Leishmania and Plasmodium falciparum is able to induce cell death in stress conditions, where it specifically activates a downstream enzyme as part of a cell death pathway. This enzymatic activity is also induced by the antimalarial drug chloroquine in erythrocytic stages of Plasmodium falciparum. Interestingly, we found that blocking parasite cell death influences their drug sensitivity, a result which could be used to create therapeutic strategies that by-pass drug resistance mechanisms by acting directly on the innate pathways of protozoan cell death

BasyLiCA: a tool for automatic processing of a bacterial live cell array

ABSTRACT Summary: Live Cell Array (LCA) technology allows the acquisition of high-resolution time-course profiles of bacterial gene expression by the systematic assessment of fluorescence in living cells carrying either transcriptional or translational fluorescent protein fusion. However, the direct estimation of promoter activities by time-dependent derivation of the fluorescence datasets generates high levels of noise. Here, we present BasyLiCA, a user-friendly open-source interface and database dedicated to the automatic storage and standardised treatment of LCA data. Data quality reports are generated automatically. Growth rates and promoter activities are calculated by tunable discrete Kalman filters that can be set to incorporate data from biological replicates, significantly reducing the impact of noise measurement in activity estimations. Availability: The BasyLiCA software and the related documentation are available a

Origins of the Ambient Solar Wind: Implications for Space Weather

The Sun's outer atmosphere is heated to temperatures of millions of degrees, and solar plasma flows out into interplanetary space at supersonic speeds. This paper reviews our current understanding of these interrelated problems: coronal heating and the acceleration of the ambient solar wind. We also discuss where the community stands in its ability to forecast how variations in the solar wind (i.e., fast and slow wind streams) impact the Earth. Although the last few decades have seen significant progress in observations and modeling, we still do not have a complete understanding of the relevant physical processes, nor do we have a quantitatively precise census of which coronal structures contribute to specific types of solar wind. Fast streams are known to be connected to the central regions of large coronal holes. Slow streams, however, appear to come from a wide range of sources, including streamers, pseudostreamers, coronal loops, active regions, and coronal hole boundaries. Complicating our understanding even more is the fact that processes such as turbulence, stream-stream interactions, and Coulomb collisions can make it difficult to unambiguously map a parcel measured at 1 AU back down to its coronal source. We also review recent progress -- in theoretical modeling, observational data analysis, and forecasting techniques that sit at the interface between data and theory -- that gives us hope that the above problems are indeed solvable.Comment: Accepted for publication in Space Science Reviews. Special issue connected with a 2016 ISSI workshop on "The Scientific Foundations of Space Weather." 44 pages, 9 figure