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81.
Sascha Rexroth Jürgen M.W. Meyer zu Tittingdorf Helena J. Schwaßmann Frank Krause Holger Seelert Norbert A. Dencher 《BBA》2004,1658(3):202-211
H+-ATP synthase is the dominant ATP production site in mitochondria and chloroplasts. So far, dimerization of ATP synthase has been observed only in mitochondria by biochemical and electron microscopic investigations. Although the physiological relevance remains still enigmatic, dimerization was proposed to be a unique feature of the mitochondrion [Biochim. Biophys. Acta 1555 (2002) 154]. It is hard to imagine, however, that closely related protein complexes of mitochondria and chloroplast should show such severe differences in structural organization. We present the first evidences for dimerization of chloroplast ATP synthases within the thylakoid membrane.By investigation of the thylakoid membrane of Chlamydomonas reinhardtii by blue-native polyacrylamide gel electrophoresis, dimerization of the chloroplast ATP synthase was detected. Chloroplast ATP synthase dimer dissociates into monomers upon incubation with vanadate or phosphate but not by incubation with molybdate, while the mitochondrial dimer is not affected by the incubation. This suggests a distinct dimerization mechanism for mitochondrial and chloroplast ATP synthase. Since vanadate and phosphate bind to the active sites, contact sites located on the hydrophilic CF1 part are suggested for the chloroplast ATP synthase dimer. As the degree of dimerization varies with phosphate concentration, dimerization might be a response to low phosphate concentrations. 相似文献
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84.
Hubschwerlen C Specklin JL Baeschlin DK Borer Y Haefeli S Sigwalt C Schroeder S Locher HH 《Bioorganic & medicinal chemistry letters》2003,13(23):4229-4233
Oxazolidinone-quinolone hybrids, which combine the pharmacophores of a quinolone and an oxazolidinone, were synthesised and shown to be active against a variety of susceptible and resistant Gram-positive and Gram-negative bacteria. The nature of the spacer greatly influences the antibacterial activity by directing the mode of action, that is quinolone- and/or oxazolidinone-like activity. The best compounds in this series have a balanced dual mode of action and overcome all types of resistance, including resistance to quinolones and linezolid, in clinically relevant Gram-positive pathogens. 相似文献
85.
K. S. Pfennig 《Proceedings. Biological sciences / The Royal Society》1998,265(1407):1743-1748
Understanding how individuals select mates becomes complex when high-quality conspecifics resemble heterospecifics. Individuals facing such a situation may be unable to effectively identify both conspecifics (species recognition) and high-quality mates that can confer fitness benefits to the choosy individual or its offspring (mate-quality recognition). Here I suggest when a conflict may occur between species and mate-quality recognition, discuss the evolutionary consequences stemming from this conflict, and present a model of mate-preference evolution in response to heterospecifics. Determining how species and mate-quality recognition interact to shape mate-choice decisions is important for understanding the diversification of sexually selected traits among closely related taxonomic groups, the use of complex sensory systems for detecting mates, and seemingly inappropriate mate-choice decisions. 相似文献
86.
Sofia Bodare Gudasalamani Ravikanth Sascha A. Ismail Mohana Kumara Patel Ilaria Spanu Ramesh Vasudeva Ramanan Uma Shaanker Giovanni Giuseppe Vendramin Martin Lascoux Yoshiaki Tsuda 《Conservation Genetics》2017,18(1):1-15
Dysoxylum malabaricum (white cedar) is an economically important tree species, endemic to the Western Ghats, India, which is the world’s most densely populated biodiversity hotspot. In this study, we used variation at ten nuclear simple sequence repeat loci to investigate genetic diversity and fine scale spatial genetic structure (FSGS) in seedlings and adults of D. malabaricum from four forest patches in the northern part of the Western Ghats. When genetic variation was compared between seedlings and adults across locations, significant differences were detected in allelic richness, observed heterozygosity, fixation index (F IS), and relatedness (P < 0.05). Reduced genetic diversity and increased relatedness at the seedling stage might be due to fragmentation and disturbance. There was no FSGS at the adult stage and FSGS was limited to shorter distance classes at the seedling stage. However, there was clear spatial genetic structure at the landscape level (<50 km), regardless of age class, due to limited gene flow between forest patches. A comparison of the distributions of size classes in the four locations with published data from a more southern area, showed that large trees (diameter at breast height, DBH, >130 cm) are present in the southern sacred forests but not in the northern forest reserves. This pattern is likely due to stronger harvesting pressure in the north compared to the south, because in the north there are no cultural taboos regulating the extraction of natural resources. The implications for forest conservation in this biodiversity hotspot are discussed. 相似文献
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88.
The increased occurrence of antibiotic resistance and the harmful use of pesticides are a major problem of modern times. A ban on the use of antibiotics as growth promoters in animal breeding has put a focus on the probiotics market. Probiotic food supplements are versatile and show promising results in animal and human nutrition. Chemical pesticides can be substituted by biopesticides, which are very effective against various pests in plants due to increased research. What these fields have in common is the use of spore-forming bacteria. The endospore-forming Bacillus spp. belonging to this group offer an effective solution to the aforementioned problems. Therefore, the biotechnological production of sufficient qualities of such endospores has become an innovative and financially viable field of research. In this review, the production of different Bacillus spp. endospores will be reviewed. For this purpose, the media compositions, cultivation conditions and bioprocess optimization methods of the last 20 years are presented and reflected. 相似文献
89.
90.
Sexual differences in habitat preferences have been reported from a variety of animal taxa. However, the ultimate causes for
this intersexual niche segregation remain poorly understood. It has been suggested that sexual dimorphism is a consequence
of dimorphic niches based upon different reproductive costs and activities of the sexes. Here we provide evidence from field
data to examine this hypothesis by studying the behavioral background of niche segregation in Tetrix ceperoi. Our data revealed distinct sexual differences in the substrates on which the insects perched and in the solar radiation
of these locations. Males were found at brighter locations and more often on bare ground than females. Incorporation of behavioral
data in our analysis showed that patches of bare ground were mainly utilized during mating behavior, in which males invested
more time than females. In contrast, females spent more time resting and feeding in the vegetation. Intersexual differences
in the proportion of autotomized individuals indicate that males might suffer higher predation risks. These patterns support
the dimorphic niches hypothesis, which suggests that differential habitat utilization is caused by differences in the life
history strategies of males and females, since males should accept a higher predation risk due to the benefits of multiple
matings. Females should invest more time in gaining nutrients and energy for egg production and survival, whereas males should
spend more time with searching for mates. We suggest that behavioral covariates should more often be implemented in ecological
analyses, since these might have a strong explanatory power. 相似文献