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.     

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...     

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.     

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.     

Fine structure of the midgut epithelium in the developing brown shrimp,Penaeus aztecus

The midgut epithelium of larval and early postlarval brown shrimp has been studied with light and electron microscopy. Ultrastructurally the features of the midgut do not change during these stages of development. On the basis of electron density, two epithelial cell types can be distinguished, and these are referred to as light and dark cells. The dark cells contain more rough endoplasmic reticulum and more free ribosomes than the light cells. Mitochondria in the dark cells have a matrix which is less electron dense than the mitochondrial matrix of the light cells. Both cell types have a microvillous border with a surface coat. The microvilli lack microfilaments within their core, and a terminal web is not differentiated in the stages examined. Tubular smooth endoplasmic reticulum is abundant in the basal portions of the cells. Electron dense, membrane bound vesicles are consistently seen in association with the Golgi apparatus, apical cell surface, and gut lumen and therefore are believed to be secretory granules. Cells in the anterior portion of the midgut often contain very large lipid droplets in the cytoplasm.     

[3H]Indole-3-Acetyl-myo-Inositol Hydrolysis by Extracts of Zea mays L. Vegetative Tissue

[³H]Indole-3-acetyl-myo-inositol was hydrolyzed by buffered extracts of acetone powders prepared from 4 day shoots of dark grown Zea mays L. seedlings. The hydrolytic activity was proportional to the amount of extract added and was linear for up to 6 hours at 37°C. Boiled or alcohol denatured extracts were inactive. Analysis of reaction mixtures by high performance liquid chromatography demonstrated that not all isomers of indole-3-acetyl-myo-inositol were hydrolyzed at the same rate. Buffered extracts of acetone powders were prepared from coleoptiles and mesocotyls. The rates of hydrolysis observed with coleoptile extracts were greater than those observed with mesocotyl extracts. Active extracts also catalyzed the hydrolysis of esterase substrates such as α-naphthyl acetate and the methyl esters of indoleacetic acid and naphthyleneacetic acid. Attempts to purify the indole-3-acetyl-myo-inositol hydrolyzing activity by chromatographic procedures resulted in only slight purification with large losses of activity. Chromatography over hydroxylapatite allowed separation of two enzymically active fractions, one of which catalyzed the hydrolysis of both indole-3-acetyl-myo-inositol and esterase substrates. With the other fraction enzymic hydrolysis of esterase substrates was readily demonstrated, but no hydrolysis of indole-3-acetyl-myo-inositol was ever detected.