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11.
Matthias Laska 《Primates; journal of primatology》1996,37(4):457-465
The purpose of this study was to test the influence of sex, age, social rank, matriline membership, posture, and visual and
tactual motor control on manual preferences inSaimiri sciureus. A well-established social group of 12 squirrel monkeys, aged 2 to 14 yrs and consisting of two matrilines with social rank
known for each animal, was presented with four different food-reaching tasks and assessed for hand preferences with a minimum
of 100 reaches per animal.
Frequency of occurrence of hand preferences at the group level and degree of hand preferences at the individual level depended
on posture and on whether the reaching act took place under visual or tactual guidance. Sex, age, social rank, and matriline
membership were not found to determine frequency of occurrence, direction or degree of hand preferences with the exception
of one task in which a significant negative correlation between the degree of hand preference and age was found. Nine out
of 12 monkeys showed task-dependent changes in the hand they used preferentially while only three animals preferred the same
hand in all four tasks. Significant preferences for the use of right or left hand on a given task were distributed almost
equally between individuals. Thus, the results of this study suggest task-specific demands like posture and/or whether reaching
was visually or tactually guided to be the major correlates of hand preferences in food-reaching tasks in squirrel monkeys. 相似文献
12.
The content of reduced glutathione and of glutathione disulfide as well as the activities of glutathione reductase, glutathione peroxidase, glutathione S-transferases, catalase and superoxide dismutases were determined in human hepatoma Hep 3B cells in relation to free-radical toxicity in order to appreciate the defense capacities of these cells compared to data on normal hepatocytes. When Hep 3B cells were exposed to lindane, a known inducer of free-radical production, superoxide dismutase activity appeared as the best-adapted cellular parameter for early detection of the resulting free-radical toxicity.Abbreviations AAS
atomic absorption spectrometry
- CDNB
1-chloro-2,4-dinitrobenzene
- DMEM
Dulbecco's modified Eagle medium
- GPx
glutathione peroxidase
- G.Red
glutathione reductase
- GSH
reduced glutathione
- GSSG
glutathione disulfide
- GST
glutathione S-transferases
- Prot
proteins
- SOD
superoxide dismutase 相似文献
13.
14.
Matthias Liebergesell Alexander Steinbüchel 《Applied microbiology and biotechnology》1993,38(4):493-501
From a genomic library of Thiocystis violaceae strain 2311 in L47, two adjacent EcoRI restriction fragments of 5361 base pairs (bp) and of 1978 bp were cloned. The 5361-bp EcoRI restriction fragment hybridized with a DNA fragment harbouring the Alcaligenes eutrophus poly(3-hydroxyalkanoate) (PHA) synthase operon (phbCAB) and restored the ability to synthesize and accumulate PHA in PHA-negative mutants derived from A. eutrophus. The nucleotide sequence analysis of both fragments revealed five open-reading frames (ORFs); at least three of them are probably relevant for PHA biosynthesis. The amino acid sequences of the putative proteins deduced from these genes indicate that they encode a -ketothiolase [phbA
Tv, relative molecular mass (Mr) 40850], which exhibited 87.3% amino acid identify with the -ketothiolase from Chromatium vinosum. The amino acid sequences of the putative proteins deduced from ORF2Tv (Mr 41 450) and phbC
Tv (Mr 39 550), which were located upstream of and antilinear to phbA
Tv, exhibited 74.7% and 87.6% amino acid identify, respectively, with the corresponding gene products of C. vinosum. Downstream of and antilinear to phbC
Tv was located ORF5, which encodes for a protein of high relative molecular mass (Mr 76428) of unknown function. With respect to the divergent organisation of ORF2Tv and phbC
Tv on one side and of phbA
Tv on the other side and from the homologies of the putative gene products, this region of the T. violaceae genome resembled very much the corresponding region of C. vinosum, which was identified recently.
Correspondence to: A. Steinbüchel 相似文献
15.
16.
Eduardo Moreno-Jiménez Fernando T. Maestre Maren Flagmeier Emilio Guirado Miguel Berdugo Felipe Bastida Marina Dacal Paloma Díaz-Martínez Raúl Ochoa-Hueso César Plaza Matthias C. Rillig Thomas W. Crowther Manuel Delgado-Baquerizo 《Global Change Biology》2023,29(2):522-532
Soil micronutrients are capital for the delivery of ecosystem functioning and food provision worldwide. Yet, despite their importance, the global biogeography and ecological drivers of soil micronutrients remain virtually unknown, limiting our capacity to anticipate abrupt unexpected changes in soil micronutrients in the face of climate change. Here, we analyzed >1300 topsoil samples to examine the global distribution of six metallic micronutrients (Cu, Fe, Mn, Zn, Co and Ni) across all continents, climates and vegetation types. We found that warmer arid and tropical ecosystems, present in the least developed countries, sustain the lowest contents of multiple soil micronutrients. We further provide evidence that temperature increases may potentially result in abrupt and simultaneous reductions in the content of multiple soil micronutrients when a temperature threshold of 12–14°C is crossed, which may be occurring on 3% of the planet over the next century. Altogether, our findings provide fundamental understanding of the global distribution of soil micronutrients, with direct implications for the maintenance of ecosystem functioning, rangeland management and food production in the warmest and poorest regions of the planet. 相似文献
17.
18.
Rhodobacter capsulatus is a member of the group α-purple bacteria which are closely related to the ancestral endosymbiont that gave rise to mitochondria. It has therefore been hypothesized that the molecular mechanisms governing protein export in α-purple bacteria have been conserved during the evolution of mitochondria. To enable analysis of protein export in α-purple bacteria we describe here the development of a homologous cell-free synthesis/export system consisting entirely of components of R. capsulatus. Translocation of precytochrome C2 into intracytoplasmic membrane vesicles of this organism was found to require the proton-motive force and proceed at a significantly higher efficiency when membranes were present during protein synthesis. Furthermore, we show that, in this cell-free system, translocation depends on a preparation of peripheral membrane proteins Which do not possess detectable SecA- and SecB-like actvities. 相似文献
19.
The 6th International Congress on Tumor Necrosis Factors and Related Molecules was held in Faliraki, Island of Rhodes, Greece, 8–12 May, 1996. This review summarizes the topics addressed and highlights some of the major advances presented during the meeting. 相似文献
20.
D. Sellmann Hans-Jörg Kremitzl Falk Knoch Matthias Moll 《Journal of biological inorganic chemistry》1996,1(2):127-135
In the quest for complexes modelling functional characteristics of metal sulfur oxidoreductases, a series of molybdenum nitrosyl complexes with sulfur-dominated coordination sphere was synthesized. Treatment of the 16, 17 and 18 valence electron (VE) complexes [Mo(L)(NO)('S4')] (1–3) [L?=?SPh (1), PMe3 (2), NO (3), 'S4'2–?=?1,2-bis-(2-mercaptophenylthio) ethane(2-)] with the Brönsted acid HBF4 resulted in formation of different types of products. 1 and 3 were reversibly protonated at one thiolate atom of the 'S4'2– ligand;2, however, yielded the phosphonium salt [HPMe3]BF4 and the dinuclear [Mo(NO)('S4')]2. Alkylation of 1, 2 and 3 by Me3OBF4 or Et3OBF4 uniformly resulted in high yields of [Mo(L)(NO)(R-'S4')]BF4 complexes [L?=?SPh: R?=?Me (5), Et (6); L?=?PMe3: R?=?Me (7); L?=?NO: R?=?Me (8), Et (9)] in which one thiolate atom of the 'S4'2– ligand had become alkylated; the NMR spectra of 5, 6, 8 and 9 indicated that only one out of four theoretically possible diastereoisomers had formed. 5 and 6 were characterized also by single-crystal X-ray structure analyses. A comparison of ν(NO) bands and redox potentials (cyclic voltammetry) of parent complexes and alkylated derivatives showed that alkylation leads to a decrease in electron density at the molybdenum center and to a positive shift in redox potentials. The 16 VE complex 1 could be reduced, also chemically, to give the corresponding 17 VE anion [1]–, and inserted elemental sulfur into the Mo-SPh bond, forming the 18 VE phenylperthio complex [Mo(η2–SSPh)(NO)('S4')] (11) which, upon reaction with PPh3, gave SPPh3 and regenerated the parent complex 1. These results are discussed with regard to the sequence of proton and electron transfer steps occurring in substrate conversions catalyzed by metal sulfur oxidoreductases. 相似文献