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.     

Formation of Ascorbate Oxidase in Cultured Pumpkin Cells

Ascorbate oxidase activity rapidly increased during callus formationfrom pumpkin fruit tissue. The activity reached a maximum at5 days after transfer and then declined. In callus which hadbeen subcultured at about 4-week intervals for more than oneyear, the activity also increased after transfer to fresh mediumand reached a maximum in the early logarithmic phase of growth.Light had little effect on the appearance of ascorbate oxidaseactivity in pumpkin callus. In the callus grown in the presenceof 10µM CuSO₄, the activity was about 10 times that inthe presence of 0.1 µM CuSO₄, suggesting that the formatonof ascorbate oxidase in pumpkin callus is stimulated by copper,a prosthetic metal of the enzyme. From 45 to 75% of the totalascorbate oxidase activity in pumpkin cell suspension cultureswas found in the medium. Ascorbate oxidase activity in the medium,as well as that in the cells, increased soon after transferto fresh medium, and reached a maximum at about 5 days. (Received July 2, 1987; Accepted November 21, 1987)     

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.     

Purification and Properties of Catalase from Sweet Potato Root Microbodies

Catalase was isolated in a pure form from sweet potato rootmicrobodies by simple procedures including ammonium sulfatefractionation and Sepharose 6B column chromatography. A singleprotein band was detected after polyacrylamide gel electrophoresisof the purified preparation. The catalase consisted of polypeptideswith a molecular weight of 60,000 when analyzed by sodium dodecylsulfate-polyacrylamidegel electrophoresis, while the molecular weight of the enzymewas about 240,000 when estimated from sucrose density gradientcentrifugation. The enzyme's ratio of absorbance at 280 nm tothat at 405 nm was about twice that of mammalian catalase. Thecatalase showed a maximal activity at pH 6.5–8.5 but wasstable only at alkaline pHs. In double immunodiffusion tests,antiserum against the purified preparation formed a single precipitinline with the crude soluble fraction from sweet potato roottissue as well as with the purified preparation. The antiserumhad no ability to inhibit the activity, but catalase in boththe crude fraction and the purified preparation was completelyprecipitated by the antiserum. (Received August 20, 1981; Accepted January 5, 1982)     

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.     

Role of O-Methyltransferase in the Lignification of Bamboo

Characterization of S-adenosylmethionine: catechol O-methyltransferase (EC. 2. 1. 1.6) isolated from bamboo shoot was carried out. Ferulic and sinapic acids which are believed to be lignin precursors are formed by the mediation of the enzyme, and the enzyme activity increased progressively during the lignification of bamboo shoots. Evidences suggest that this enzyme may contribute to the synthesis of lignin precursors.     

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.