Some Problems in the Assay Method of HMG-CoA Reductase Activity in Sweet Potato in the Presence of Other HMG-CoA Utilizing Enzymes

In addition to HMG-CoA reductase, another HMG-CoA utilizing enzyme is present in the Mt fraction of sweet potato root tissue and its activity interferes with the assay to HMG-CoA reductase activity.     

Effect of snow removal on leaf water potential,soil moisture,leaf and soil nutrient status and leaf peroxidase activity of sugar maple

Effect of removal of snow cover in winter was investigated in an 80-year-old sugar maple (Acer saccharum Marsh.) stand in southern Quebec. We hypothesized that winter soil frost would induce some of the decline symptoms observed in sugar maple stands in southern Quebec in the early 1980's. Snow was continuously removed from around trees for a one week (partial removal) or for a four-month period (complete removal) during the 1990–1991 winter. Foliage and soils were sampled periodically during the summer of 1991. The complete snow removal treated trees showed decreased leaf water potential and increased peroxidase activity over most of the growing season. Foliar Ca was reduced in both snow removal treatments early in the growing season while foliar N was reduced in the complete snow removal trees late in the growing season. Soil NO ₃ ^– and K⁺ were elevated in both snow removal treatments at various times throughout the growing season. Prolonged soil frost in a sugar maple stand can induce lower leaf water potential, higher leaf peroxidase activity and early leaf senescence during the following growing season. Soil frost may have reduced nutrient uptake without affecting significantly the leaf nutrient status.     

Social Tolerance in Wild Female Crested Macaques (Macaca nigra) in Tangkoko‐Batuangus Nature Reserve,Sulawesi, Indonesia

In primates, females typically drive the evolution of the social system and present a wide diversity of social structures. To understand this diversity, it is necessary to document the consistency and/or flexibility of female social structures across and within species, contexts, and environments. Macaques (Macaca sp.) are an ideal taxon for such comparative study, showing both consistency and variation in their social relations. Their social styles, constituting robust sets of social traits, can be classified in four grades, from despotic to tolerant. However, tolerant species are still understudied, especially in the wild. To foster our understanding of tolerant societies and to assess the validity of the concept of social style, we studied female crested macaques, Macaca nigra, under entirely natural conditions. We assessed their degree of social tolerance by analyzing the frequency, intensity, and distribution of agonistic and affiliative behaviors, their dominance gradient, their bared‐teeth display, and their level of conciliatory tendency. We also analyzed previously undocumented behavioral patterns in grade 4 macaques: reaction upon approach and distribution of affiliative behavior across partners. We compared the observed patterns to data from other populations of grade 4 macaques and from species of other grades. Overall, female crested macaques expressed a tolerant social style, with low intensity, frequently bidirectional, and reconciled conflicts. Dominance asymmetry was moderate, associated with an affiliative bared‐teeth display. Females greatly tolerated one another in close proximity. The observed patterns matched the profile of other tolerant macaques and were outside the range of patterns of more despotic species. This study is the first comprehensive analysis of females’ social behavior in a tolerant macaque species under natural conditions and as such, contributes to a better understanding of macaque societies. It also highlights the relevance of the social style concept in the assessment of the degree of tolerance/despotism in social systems. Am. J. Primatol. 75:361‐375, 2013. © 2013 Wiley Periodicals, Inc.     

Mutants impaired in vacuolar metal mobilization identify chloroplasts as a target for cadmium hypersensitivity in Arabidopsis thaliana

Cadmium (Cd) is highly toxic to plants causing growth reduction and chlorosis. It binds thiols and competes with essential transition metals. It affects major biochemical processes such as photosynthesis and the redox balance, but the connection between cadmium effects at the biochemical level and its deleterious effect on growth has seldom been established. In this study, two Cd hypersensitive mutants, cad1‐3 impaired in phytochelatin synthase (PCS1), and nramp3nramp4 impaired in release of vacuolar metal stores, have been compared. The analysis combines genetics with measurements of photosynthetic and antioxidant functions. Loss of AtNRAMP3 and AtNRAMP4 function or of PCS1 function leads to comparable Cd sensitivity. Root Cd hypersensitivities conferred by cad1‐3 and nramp3nramp4 are cumulative. The two mutants contrast in their tolerance to oxidative stress. In nramp3nramp4, the photosynthetic apparatus is severely affected by Cd, whereas it is much less affected in cad1‐3. In agreement with chloroplast being a prime target for Cd toxicity in nramp3nramp4, the Cd hypersensitivity of this mutant is alleviated in the dark. The Cd hypersensitivity of nramp3nramp4 mutant highlights the critical role of vacuolar metal stores to supply essential metals to plastids and maintain photosynthetic function under Cd and oxidative stresses.     

Studies on the Chitinolytic Enzymes of Black-koji Mold

The mode of degradation of glycol chitin and chitin by two enzyme fractions separated from Aspergillus niger was investigated. One of the enzyme rapidly cleaved the endo-β-glucosaminidic bonds in the polysaccharide chain, forming chitodextrin and oligosaccharides, while the other produced monosaccharide as a main product in the degradation. The successive action of the two enzymes was also examined. Intermediate products in the enzymatic degradation were surveyed using paper and column chromatography. Also, the over-all pattern of degradation of glycol chitin and chitin by the chitinase system of Aspergillus niger was discussed.     

Morphological and molecular taxonomy of a new Daptonema (Nematoda,Xyalidae) with comments on the systematics of some related taxa

A new species of Daptonema is described based upon morphological characters and 18S rRNA sequence. Daptonema matrona sp. nov. was collected in Pina Basin (north‐eastern Brazil). It differs from all other species of the genus by the presence of reduced cephalic setae and straight spicules. These features require an adaptation of the generic diagnosis. Moreover, the females are characterized by intra‐uterine development of the offspring, considered herein as their major autapomorphic feature. Molecular systematic analyses supported Daptonema matrona sp. nov. as a distinct genetic and evolutionary lineage. The data also indicate hypotheses of taxonomic synonymies amongst some related taxa from Xyalidae as well as the paraphyly of Daptonema. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158 , 1–15.     

An integrative approach to characterize cryptic species in the Thoracostoma trachygaster Hope, 1967 complex (Nematoda: Leptosomatidae)

Nematode diversity may seriously be underestimated when taking into account cryptic speciation. Thoracostoma trachygaster is commonly found in kelp holdfasts along the California coastline and was recently shown to consist of at least two distinct molecular clades (I and II). Here, we provide detailed morphological analysis of both clades, based on measurements taken from video vouchers of respectively eight and 16 individuals from the previous study, as well as 80 newly collected specimens from four Californian beaches. The latter were vouchered, measured, and then subjected to molecular analyses of the mitochondrial cytochrome oxidase c subunit I (COI) gene, and the ribosomal D2D3 and internal transcribed spacer (ITS) regions. This integrative approach shows that the three molecular clades are phylogenetically and morphologically distinct species, but a combination of morphological characters is needed to distinguish them. Two new species, Thoracostoma fatimae sp. nov. and Thoracostoma igniferum sp. nov. , are identified and described. The spicule length of T. fatimae sp. nov. is significantly shorter than that of T. trachygaster. Thoracostoma igniferum sp. nov. can be distinguished by the irregular posterior edge of the cephalic capsule and the two internal subdorsal tropis‐like projections in the wall of the cephalic capsule, which are lacking in T. fatimae sp. nov. and T. trachygaster. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 164 , 18–35.     

Are there costs in the repeated mating activities of female Southern stink bugs Nezara viridula?

Mating is an energy demanding process, imposing risks to physical injuries, pathogen infection and predation. Nevertheless, repeated and multiple mating are widespread even in insect species where nuptial gifts are not involved. The effects of repeated mating, by the same male, are examined on the reproductive performance of female Southern green stink bug Nezara viridula (L.). Fecundity is reduced in females mated three or four times, although there is increased longevity. Females mated once or twice produce more egg clusters and concentrate egg‐laying activity in the early part of adult life, whereas those mating more often lay eggs throughout the life span, with fewer egg clusters. Although fecundity is negatively affected by the number of matings, egg fertility remains unaffected.