Proteomic analysis of root meristems and the effects of acetohydroxyacid synthase-inhibiting herbicides in the root of Medicago truncatula

Quantitative proteome analyses of meristematic and nonmeristematic tissues from Medicago truncatula primary and lateral roots and meristem tissues from plants treated with acetohydroxyacid synthase-inhibiting herbicides were made. The accumulation of 81 protein spots changed in meristematic and nonmeristematic tissues and 51 protein spots showed significant changes in accumulation in herbicide-treated meristems. Identified proteins indicate two trends, (i) increased accumulation of cell division and redox-mediating proteins in meristems compared to nonmeristematic tissues and (ii) increased accumulation of pathogenesis-related and decreased accumulation of metabolic proteins in herbicide-treated roots.     

Development of a Rapid and Simple Digestion Method of Freshwater Sediments for As,Cd, Cr,Cu, Pb,Fe, and Zn Determination by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES): An Evaluation of Dilute Nitric Acid

In this study, a simple and rapid methodology based on the hot-plate digestion method using dilute nitric acid solution was used to extract trace metals (such as As, Cd, Cr, Cu, Pb, Fe, and Zn) from freshwater sediments. The concentrations of the elements were determined using inductively coupled plasma-optical emission spectrometry (ICP-OES). The factors (temperature, nitric acid concentration, and volume) affecting the digestion method were optimized using one-factor-at-a-time (OFAT) or univariate methodology, and the optimization process was carried out using freshwater sediment certified reference material (CRM015). The optimal conditions for temperature, nitric acid concentration, and time in the method were 180°C, 10 mL of 5 mol L^?1 HNO₃, and 45 min, respectively. Under optimum conditions, the limit of detection (LOD) ranged between 0.02 and 0.08 µg L^?1 and the limit of quantification (LOQ) ranged from 0.07 and 0.27 µg L^?1. In addition, the method detection limits (MDLs) and method quantification limits (MQLs) were 0.10–0.17 and 0.30?0.57 µg g^?1, respectively. The overall accuracy of the method determined by recovery of the trace elements in the CRMs ranged from 98 to 111% with the precision ranging from 1.4 to 5.8%. The method was successfully applied for the determination of target metals from real freshwater sediment samples.     

A new procedure for rapidly scoring acrosome reactions of human sperm

Because the acrosome of human sperm is too small to be directly visualized by phase-contrast microscopy, acrosome reactions (that is loss of the acrosome) are generally not evaluated in studies of human sperm capacitation and fertilization. Nevertheless, it would be useful in such studies to have a technique for easily identifying and quantitating acrosome-reacted sperm. In this paper, we describe a method for labeling the human sperm acrosome with fluorescein-conjugated Ricinus communis agglutinin-60 (FITC-RCA); we show that in sperm without acrosomal caps, FITC-RCA labeling occurs either not at all or only in the equatorial segment of the acrosome. To determine if the absence of FITC-RCA labeling in the acrosomal cap region gives a reliable estimate of acrosome reactions, washed sperm or sperm incubated in a capacitating medium (BWW) were divided into two groups, which were then fixed for FITC-RCA labeling or transmission electron microscopy. Counts of acrosome reactions made by each method were similar, and we observed an increase in the percentage of reactions following incubation in BWW. We conclude that the FITC-TCA labeling technique is a reliable method for accurately scoring the percentage of acrosome-reacted human sperm.     

Structural and functional studies of the adrenal zona glomerulosa in sodium-depleted and sodium-loaded sheep

Cell and Tissue Research - The effects of alterations in sodium status upon the morphology of the adrenal zona glomerulosa in sheep have been examined qualitatively and quantitatively, using...     

A Novel Approach to Block HIV-1 Coreceptor CXCR4 in Non-toxic Manner

The chemokine receptor CXCR4 is one of the major coreceptors for human immunodeficiency virus type 1 (HIV-1) and considered as an important therapeutic target. Knockdown of CXCR4 by RNA interference has emerged as a promising strategy for combating HIV-1 infection. However, there is a potential drawback to this strategy as undesired side effects may occur due to the loss of natural function of CXCR4. In this study, we developed a novel approach using a single lentiviral vector to express simultaneously CXCR4 dual-shRNAs and an shRNA-resistant CXCR4 mutant possessing the most possible natural functions of CXCR4 and reduced HIV-1 coreceptor activity. Via this approach we achieved the replacement of endogenous CXCR4 by CXCR4 mutant P191A that could compensate the functional loss of endogenous CXCR4 and significant reduction of HIV-1 replication by 59.2 %. Besides, we demonstrated that construction of recombinant lentiviral vector using 2A peptide-based strategy has significant advantages over using additional promoter-based strategy, including increase of lentivirus titer and avoidance of promoter competition. Therefore, the novel approach to block HIV-1 coreceptor CXCR4 without impairing its normal function provides a new strategy for CXCR4-targeted therapeutics for HIV-1 infection and potential universal applications to knock down a cellular protein in non-toxic manner.     

Acid Hydrolysis and Molecular Density of Phytoglycogen and Liver Glycogen Helps Understand the Bonding in Glycogen α (Composite) Particles

Phytoglycogen (from certain mutant plants) and animal glycogen are highly branched glucose polymers with similarities in structural features and molecular size range. Both appear to form composite α particles from smaller β particles. The molecular size distribution of liver glycogen is bimodal, with distinct α and β components, while that of phytoglycogen is monomodal. This study aims to enhance our understanding of the nature of the link between liver-glycogen β particles resulting in the formation of large α particles. It examines the time evolution of the size distribution of these molecules during acid hydrolysis, and the size dependence of the molecular density of both glucans. The monomodal distribution of phytoglycogen decreases uniformly in time with hydrolysis, while with glycogen, the large particles degrade significantly more quickly. The size dependence of the molecular density shows qualitatively different shapes for these two types of molecules. The data, combined with a quantitative model for the evolution of the distribution during degradation, suggest that the bonding between β into α particles is different between phytoglycogen and liver glycogen, with the formation of a glycosidic linkage for phytoglycogen and a covalent or strong non-covalent linkage, most probably involving a protein, for glycogen as most likely. This finding is of importance for diabetes, where α-particle structure is impaired.     

Compartment-Specific Biosensors Reveal a Complementary Subcellular Distribution of Bioactive Furin and PC7

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