Multispectral imaging flow cytometry reveals distinct frequencies of γ-H2AX foci induction in DNA double strand break repair defective human cell lines

Copyright @ 2012 International Society for Advancement of Cytometry. The article can be accessed from the links below.This article has been made available through the Brunel Open Access Publishing Fund.The measurement of γ-H2AX foci induction in cells provides a sensitive and reliable method for the quantitation of DNA damage responses in a variety of cell types. Accurate and rapid methods to conduct such observations are desirable. In this study we have employed the novel technique of multispectral imaging flow cytometry to compare the induction and repair of γ-H2AX foci in three human cell types with different capacities for the repair of DNA double strand breaks (DSB). A repair normal fibroblast cell line MRC5-SV1, a DSB repair defective ataxia telangiectasia (AT5BIVA) cell line, and a DNA-PKcs deficient cell line XP14BRneo17 were exposed to 2 Gy gamma radiation from a 60Cobalt source. Thirty minutes following exposure we observed a dramatic induction of foci in the nuclei of these cells. After 24 hrs there was a predictable reduction on the number of foci in the MRC5-SV1 cells, consistent with the repair of DNA DSB. In the AT5BIVA cells, persistence of the foci over a 24 hour period was due to the failure in the repair of DNA DSB. However, in the DNA-PKcs defective cells (XP14BRneo17) we observed an intermediate retention of foci in the nuclei indicative of partial repair of DNA DSB. In summary, the application of imaging flow cytometry has permitted an evaluation of foci in a large number of cells (20,000) for each cell line at each time point. This provides a novel method to determine differences in repair kinetics between different cell types. We propose that imaging flow cytometry provides an alternative platform for accurate automated high through-put analysis of foci induction in a variety of cell types.This article is made available through the Brunel Open Access Publishing Fund

Phytochemical Survey of Orchids in the Tirunelveli Hills of South India

Phytochemical investigations of the orchid family were performed for alkaloid constituents, identification and inheritance of flower pigments in the species of ornamental value. Apart from the presence of chlorophyll in green flowered forms and carotenoids in some yellow flowers, anthocyanidins are predominated. The cyaniding, pelargonidin and petunidin, and complex mixture of their glycosides and acylated derivatives are often present in a single flower. In the present investigation of the preliminary phytochemical study of leaf flavanoids contents of Orchidiaceae family members in the Tirunelveli hills of South India were analyzed and surveyed

Electroconvection in a Suspended Fluid Film: A Linear Stability Analysis

A suspended fluid film with two free surfaces convects when a sufficiently large voltage is applied across it. We present a linear stability analysis for this system. The forces driving convection are due to the interaction of the applied electric field with space charge which develops near the free surfaces. Our analysis is similar to that for the two-dimensional B\'enard problem, but with important differences due to coupling between the charge distribution and the field. We find the neutral stability boundary of a dimensionless control parameter ${\cal R}$ as a function of the dimensionless wave number ${\kappa}$. ${\cal R}$, which is proportional to the square of the applied voltage, is analogous to the Rayleigh number. The critical values ${{\cal R}_c}$ and ${\kappa_c}$ are found from the minimum of the stability boundary, and its curvature at the minimum gives the correlation length ${\xi_0}$. The characteristic time scale ${\tau_0}$, which depends on a second dimensionless parameter ${\cal P}$, analogous to the Prandtl number, is determined from the linear growth rate near onset. ${\xi_0}$ and ${\tau_0}$ are coefficients in the Ginzburg-Landau amplitude equation which describes the flow pattern near onset in this system. We compare our results to recent experiments.Comment: 36 pages, 7 included eps figures, submitted to Phys Rev E. For more info, see http://mobydick.physics.utoronto.ca

Effect of ground flaxseed on the carcass characteristics of Karadi male lambs

To investigate the effect of dietary supplementation of Ground Flaxseed (GF) on performance and carcass characteristics of Karadi male lambs. Flaxseed was used in feeding period that lasted for 90 days using twelve ram Karadi lambs, at 6 months old, which divided into 3 equal groups (4 rams/group). The lambs were randomly allocated into three treatments to receive either control ration (no Ground flaxseed), or ration containing 4% Ground Flaxseed (T1), or diet containing 8% Ground Flaxseed (T2). All the lambs were received an equal daily allowance of concentrate ration (3% of the body weight). At the end of feeding trial (8 weeks), all the lambs were slaughtered. They were weighed immediately before slaughter to provide slaughter body weight (SBW). Immediately after skinning, evisceration was carried out and the carcass components were weighted. Then several quantity characteristics for carcasses were studied, which include: hot carcass weight (HCW), dressing percentage, thickness of subcutaneous fat, rib eye area, partition and cutting of Carcass. Data were analyzed using XL Stat. The results showed that GF has no significant effect on live body weight, hot carcass weight, and dressing percentage %, it also has no significant differences on some carcass cuts for example: leg, shoulder, loin, rack, fore shank and neck. On the other hand, GF supplementation caused a significant (P2). Some of the carcass cuts, Breast and Flank, decreased significantly (P<0.05) in T2 compared to T1 and Control. In conclusion, GF supplementation significantly decrease breast and flank cuts, while rib eye area significantly increased. However, the decrease in fat thickness may be reflecting the decrease in fat percentages in the carcass that indicates the effect of GF in improvement of carcass traits

Seagrass meadows are important sources of reef island-building sediment

This is the final version. Available on open access from Nature Research via the DOI in this recordThe future vulnerability of low-lying atoll nations is inextricably linked to the production of island-building carbonate sediments by organisms living in their adjacent marine environments. Seagrass meadows are commonly found adjacent to reef islands, but their potential role as sources of reef island-building sediments has been overlooked. Here, we quantify rates of sediment production by seagrass epibionts in a reef island sediment supply context. Total seagrass epibiont sediment production at our study site (Huvadhoo Atoll, Maldives) was 853,000 ± 90,000 kg CaCO3 yr-1 over an area of 1.1 km2. Of this total sediment production, 541,000 ± 23,000 kg CaCO3 yr-1 was estimated to be suitable to contribute to reef island building (i.e., sand-sized, post-agitation). Our findings highlight a previously unrecognised and highly valuable ecosystem service provided by tropical seagrass meadows as important potential sources of reef island-building sediment. This study, therefore, presents a new and compelling geomorphic argument for seagrass conservation.British Society for Geomorpholog

Preparación y caracterización de cementos belíticos blancos activados con dopantes alcalinos

Activated white cement clinkers with a theoretical 60% (wt) belite (dicalcium silicate) content were prepared at a temperature 100 ºC lower than used to manufacture conventional white Portland cement clinkers. Activation was achieved by adding variable amounts of K2CO 3 or Na2CO 3 to the raw mixes. Rietveld quantitative analysis of X-ray diffraction findings showed that adding the alkalis stabilized the high temperature belite polymorphs. When 2.0% (wt) of Na2O was added, the composition (by wt) found was 16.4(4)% alpha-C2S, 16.7(8)% alpha’-H-C2S, 23.2(6)% beta-C2S, 32.7(7)% total C3S, 9.5(2)% orthorhombic C3A and 1.50(5)% free lime. Due to the high volatilization rate of K2O under the experimental conditions, it stabilized the alpha-type C2S less effectively than Na2O. A calorimetric study was likewise performed to correlate the phase composition with early age hydration (behaviour).Se han preparado clínkeres blancos activados con un porcentaje en peso teórico de belita (silicato dicálcico) del 60%, a una temperatura 100 ºC menor que los clínkeres Portland blancos convencionales. El proceso de activación se ha llevado a cabo añadiendo a las mezclas crudas cantidades variables de K2CO3 o Na2CO 3. Utilizando la difracción de rayos-X y la metodología de Rietveld se ha comprobado la estabilización a temperatura ambiente de porcentajes variables de los polimorfos de alta temperatura de la belita por la adición de alcalinos. De hecho, al añadir 2,0% en peso de Na2O se ha obtenido 16,4(4)% de alfa-C2S, 16,7(8)% de alfa’-H-C2S, 23,2(6)% de beta-C2S, 32,7(7)% de C3S total, 9,5(2)% de C3A ortorrómbico y 1,50(5)% de cal libre, porcentajes en peso. Se ha comprobado que el grado de volatilización de los alcalinos, en estas condiciones de preparación, ha sido muy acusado para el K2O, lo que ha provocado una menor estabilización de los polimorfos tipo-alfa-C2S. Además, se ha realizado un estudio calorimétrico para correlacionar el ensamblaje de fases con el comportamiento de hidratación a edades tempranas

Primary prevention of severe lower respiratory illnesses in at-risk infants using the immunomodulator OM85

Severe lower respiratory illnesses (sLRI) during infancy increase the risk of asthma. The immunomodulator BronchVaxom® can increase the time to the first sLRI and reduce the cumulative burden of sLRI in "at risk" infants