Phylogeography of the temperate grassland plant Tephroseris kirilowii (Asteraceae) inferred from multiplexed inter-simple sequence repeat genotyping by sequencing (MIG-seq) data

Journal of Plant Research - A group of temperate grassland plant species termed the “Mansen elements” occurs in Japan and is widely distributed in the grasslands of continental East...     

Spermatogenesis in Animals as Revealed by Electron Microscopy : VI. Researches on the Spermatozoon-Dimorphism in a Pond Snail, Cipangopaludina malleata

This paper reports an electron microscope study of typical and atypical spermatogenesis in the pond snail, Cipangopaludina malteata. In the typical spermatid the nucleus undergoes profound changes as development proceeds, affecting both its form and internal fine structure. A large number of roughly parallel, dense filaments, arranged along the long axis of the nucleus, fuse with each other to form in the end the homogeneous helical body characteristic of the head of the adult spermatozoa. The nebenkern is apparently mitochondrial in nature and, in its early development, is similar to that of insects except that it appears as a double structure from the beginning. As differentiation proceeds, the mitochondria lose their membranes, and the residual, now denuded cristae, reorganize to give a parallel radial arrangement. In the last stages of development, the nebenkern derivations become applied to the sheath of the middle piece in a compact helical fashion. In the development of the atypical spermatozoa, the nucleus fails to differentiate and simply shrinks in volume until only a remnant, devoid of DNA, is left. The cytoplasm shows numerous vesicles containing small Feulgen-positive bodies, 80 to 130 mµ in diameter. These vesicles plus contents increase in number as spermatogenesis proceeds. The "head" structure of the atypical spermatozoa consists of a bundle (7 to 17) of tail flagella, each with a centriole at its anterior end. The end-piece of the atypical form appears brush-like and is made up of the free ends of the several flagella.     

Purification and characterization of pig lung carbonyl reductase.

A pyrazole-sensitive carbonyl reductase from pig lung was purified to homogeneity by electrophoretic criteria. Chemical cross-linking study suggested that the native enzyme is a tetramer with a Mr of 103,000, consisting of apparent identical subunits of Mr 24,000. The enzyme reduced aliphatic and aromatic carbonyl compounds with NADPH as a preferable cofactor to NADH and catalyzed the oxidation of secondary alcohols and the aldehyde dismutation in the presence of NAD(P)+. Immunohistochemical study with the antibodies against the enzyme revealed that the enzyme was localized in the ciliated cells, nonciliated bronchiolar cells, Type II alveolar pneumocytes, and the epithelial cells of the ducts of the bronchial glands in the pig lung. In addition to the properties and distribution, the pig lung enzyme was immunochemically similar to the pulmonary enzymes in the guinea pig and mouse. However, the pig enzyme showed the following unusual features. (1) The enzyme exhibited an equatorial specificity in the reduction of 3-ketosteroids; the 4-pro-S hydrogen of NADPH was transferred to the carbonyl carbon atom of 5 alpha- and 5 beta-androstanes, and the respective reduced products were identified as 3 beta- and 3 alpha-hydroxysteroids. (2) Although the NADPH-linked reduction of carbonyl compounds apparently obeyed the Michaelis-Menten kinetics at pH 6.0, the double-reciprocal plots of the velocity vs concentrations of the carbonyl substrates were convex at pH higher than 6.5. The Hill coefficients and [S]0.5 values for the substrates decreased as the pH for reaction increased. The results suggest that the pig enzyme exhibits negative cooperativity with respect to the carbonyl substrates and that the hydrogen ion acts as an allosteric effector abolishing the negative interaction.     

A Novel Isourazole Herbicide, Fluthiacet-Methyl, is a Potent Inhibitor of Protoporphyrinogen Oxidase after Isomerization by Glutathione S-Transferase

A novel isourazole herbicide, fluthiacet-methyl (methyl [[2-chloro-4-fluoro-5-[(5,6,7,8-tetrahydro-3-oxo-lH,3H-[l,3,4]thiadiazolo[3,4-a]pyridazin-l-ylidene)amino]phenyrjthio]acetate;experimental code name, KIH-9201) promoted the leakage of electrolytesfrom cotyledons of velvetleaf (Abtilon theophtasti Medic) andcotton (Gossypium hirsutum L.) plants that are sensitive tothis compound. It induced the accumulation of protoporphyrinIX in cotyledons of cotton and inhibited Chl biosynthesis incotyledons of velvetleaf and cotton at low concentrations (I₅₀values, 10–12 nM). Fluthiacet-methyl was converted toits urazole by glutathione S-transferase that had been partiallypurified from velvetleaf. The urazole inhibited protoporphyrinogenoxidase (Protox, EC 1.3.3.4 [EC] ) from some plants, including velvetleaf,at low concentrations (I₅₀ values, 5.1–11 nM), whereasfluthiacet-methyl was not as potent. The effects in vivo (electrolyteleakage and inhibition of Chi biosynthesis) of fluthiacet-methylwere correlated with the inhibition of Protox activity by theurazole and not with the action of fluthiacet-methyl itself.From these results, it is concluded that fluthiacet-methyl inhibitsProtox activity after conversion to the corresponding urazoleby glutathione S-transferase. It is in this way that fluthiacet-methylexerts its effect as a light-dependent peroxidizing herbicide. (Received November 1, 1994; Accepted March 6, 1995)     

Water Soluble Pigments Containing Xylose and Glucose in Gametangia of the Green Alga, Bryopsis maxima

Several water-soluble pigments were purified from gametangiaof Bryopsis maxima by liquid chromatography and characterizedby pyridylamination and high-performance anion-exchange chromatography.The structure of the main red pigment is proposed based on thedata of infrared spectrum, Mass spectrum, ¹H and ¹³C NMR spectraand pyridylamino analysis. As a consequence, this pigment containeda tetrapyrrole with phytol and a sugar chain comprised of xyloseand glucose. The sequence of the sugars in the chain was determinedbased on its Mass spectrum. The pigment was similar to chlorophyll-originpigments observed in other plants. No aldehyde group, however,was present at C5 in the open tetrapyrrole chain. (Received August 3, 1994; Accepted November 10, 1994)     

Site-directed mutagenesis of histidine residues in Clostridium perfringens alpha-toxin.

Mutagenesis of H-68 or -148 in Clostridium perfringens alpha-toxin resulted in complete loss of hemolytic, phospholipase C, sphingomyelinase, and lethal activities of the toxin. These activities of the variant toxin at H-126 or -136 decreased by approximately 100-fold of the activities of the wild-type toxin. Mutation at H-46, -207, -212, or -241 showed no effect on the biological activities, indicating that these residues are not essential for these activities. The variant toxin at H-11 was not detected in culture supernatant and in cells of the transformant carrying the variant toxin gene. Wild-type toxin and the variant toxin at H-148 bound to erythrocytes in the presence of Ca2+; however, the variant toxins at H-68, -126, and -136 did not. Co2+ and Mn2+ ions stimulated binding of the variant toxin at H-68, -126, and -136 to membranes in the presence of Ca2+ and caused an increase in hemolytic activity. Wild-type toxin and the variant toxins at H-68, -126, and -136 contained two zinc atoms in the molecule. Wild-type toxin inactivated by EDTA contained two zinc atoms. These results suggest that wild-type toxin contains two tightly bound zinc atoms which are not coordinated to H-68, -126, and -136. The variant toxin at H-148 possessed only one zinc atom. Wild-type toxin and the variant toxin at H-148 showed [65Zn]2+ binding, but the variant toxins at H-68, -126, and -136 did not. Furthermore, [65Zn]2+ binding to wild-type toxin was competitively inhibited by unlabeled Zn2+, Co2+, and Mn2+. These results suggest that H-68, -126, and -136 residues bind an exchangeable and labile metal which is important for binding to membranes and that H-148 tightly binds one zinc atom which is essential for the active site of alpha-toxin.     

1H-, 13C-, and 113Cd-nmr study of the Cd(II) complex of a blocked peptide,Z-Cys-Ala-Pro-His-OMe,in organic solvents

The Cd(II) complex of a peptide, Z-Cys-Ala-Pro-His-OMe was prepared and characterized by absorption, CD, ¹H-, ¹³C-, and ¹¹³Cd-nmr, and nuclear Overhauser effect spectroscopy (NOESY) spectra to show the coordination of cysteine thiolate and histidine imizazole to Cd(II) ion. The NOESY spectra in dimethyl formamide showed that the cysteine residue was in proximity to the histidine residue. These results reveal the dictation of Z-Cys-Ala-Pro-His-OMe to Cd(II) ion in solution. Temperature-dependent dissociation equilibrium of histidine imidazole in solution was observed in this complex. Structural features of the chelating peptide are discussed. © 1995 John Wiley & Sons, Inc.