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31.
Background
Identification of novel drug targets and their inhibitors is a major challenge in the field of drug designing and development. Diaminopimelic acid (DAP) pathway is a unique lysine biosynthetic pathway present in bacteria, however absent in mammals. This pathway is vital for bacteria due to its critical role in cell wall biosynthesis. One of the essential enzymes of this pathway is dihydrodipicolinate synthase (DHDPS), considered to be crucial for the bacterial survival. In view of its importance, the development and prediction of potent inhibitors against DHDPS may be valuable to design effective drugs against bacteria, in general. 相似文献32.
The orthocladiine Chironomidae genus Stictocladius Edwards was described originally from South America. Although recognised subsequently as present also in Australia and New Zealand, the true diversity in the Neotropics has remained unclear. After more than a decade of collections of both isolated adults and aquatic immature stages, we can recognise several new taxa and associate some immature stages. Thus, we describe Stictocladius prati n. sp. as male, female, pupa and larva; Stictocladius acutus n. sp. and Stictocladius acrilobus n. sp. as male, female and pupa; Stictocladius fimbriatus n. sp. as male and female; Stictocladius fovigus n. sp. and Stictocladius nudiventer n. sp. as male and pupa; and Stictocladius privicalcar n. sp. and Stictocladius prostatus n. sp. each as male imago alone. The male and female of Stictocladius pulchripennis Edwards is redescribed and the pupa described. The male and female of Stictocladius flavozonatus Edwards and the male of Stictocladius calonotum Edwards are described. Five pupal types are described: Stictocladius sp. A (near S. acrilobus), Stictocladius sp. B (possibly S. calonotum), Stictocladius sp. C (near S. calonotum), Stictocladius sp. D (possibly S. flavozonatus) and Stictocladius sp. E with uncertain affinity. A larva from Chile of the Stictocladius ??sofour type?? (Stictocladius sp. F) and an unreared larva from North America (Stictocladius sp. G) possibly belonging to S. acutus are described. Keys to named Neotropical male and female imagines of Stictocladius and to all pupal forms of Neotropical Stictocladius are provided. Some data concerning fourth instars of Stictocladius are presented. Means of differentiation from putative sister taxon Lopescladius are discussed. 相似文献
33.
This essay complements that de Baat et al1 in the last issue with emphasis on the importance of the variability between individual older people. The consequent need for an open minded approach towards planning Prosthodontics is discussed, based on each patient's motivation for aesthetics, function, comfort and self esteem. Both functional expectations and motivation to learn effective health behaviour vary widely, and evaluation of both is essential for realistic planning because further tooth loss and the need for partial dentures occur so frequently. The consequent variation in plans raises the question – which are the strategic teeth to maintain a stable dental occlusion or a future tooth stabilised denture? For undergraduates this demands a non-rote approach to learning. 相似文献
34.
Bussari B Saudagar PS Shaligram NS Survase SA Singhal RS 《Journal of industrial microbiology & biotechnology》2008,35(1):49-58
Cephamycin C is an extracellular broad spectrum β-lactam antibiotic produced by Streptomyces clavuligerus, S. cattleya and Nocardia lactamdurans. In the present study, different substrates for solid-state fermentation were screened for maximum cephamycin C production
by S. clavuligerus NT4. The fermentation parameters such as substrate concentration, moisture content, potassium dihydrogen phosphate, inoculum
size and ammonium oxalate were optimized by response surface methodology (RSM). The optimized conditions yielded 21.68 ± 0.76 mg gds−1 of cephamycin C as compared to 10.50 ± 1.04 mg gds−1 before optimization. Effect of various amino acids on cephamycin C production was further studied by using RSM, which resulted
in increased yield of 27.41 ± 0.65 mg gds−1. 相似文献
35.
Clavulanic acid: a review 总被引:1,自引:0,他引:1
Natural antibiotics are almost universal secondary metabolites, not essential for the growth of the producing organisms generally produced at low growth rates or after growth has ceased. Clavulanic acid (CA), a naturally occurring powerful inhibitor of bacterial beta-lactamases is a major beta-lactam antibiotic produced by organism Streptomyces clavuligerus and is active against a wide spectrum of Gram-positive and Gram-negative bacteria. The review discusses the biosynthetic pathway, fermentative production, downstream processing and applications of CA. 相似文献
36.
Background
Severe cardiotoxicity is a documented, but very unusual side-effect of intravenous 5-fluorouracil therapy. The mechanism producing cardiotoxicity is poorly understood. 相似文献37.
Background
Specification of primordial germ cells in mice depends on instructive signalling events, which act first to confer germ cell competence on epiblast cells, and second, to impose a germ cell fate upon competent precursors. fragilis, an interferon-inducible gene coding for a transmembrane protein, is the first gene to be implicated in the acquisition of germ cell competence. 相似文献38.
The aim of this work was to study the effect of addition of different amino acids and sugar nucleotides as metabolic precursors on the production of scleroglucan. A maximum yield of 20.00 g/l and 22.32 g/l was obtained with optimized media supplemented with L-lysine (1.1 mM) and uridine mono-phosphate (UMP), respectively as compared to 16.52 g/l scleroglucan achieved with the control in the absence of metabolic precursors. 相似文献
39.
Optimization of nutritional requirements and feeding strategies for clavulanic acid production by Streptomyces clavuligerus 总被引:1,自引:0,他引:1
The present work reports the nutritional requirements and environmental conditions for submerged culture of Streptomyces clavuligerus for clavulanic acid production using orthogonal matrix method (Taguchi L(16) design) and also fed-batch fermentation for clavulanic acid production by feeding glycerol, arginine and threonoine to the fermentation medium intermittently. Clavulanic acid production was increased by 18% with the span of feeding glycerol and reached a maximum at 1.30mg/ml with 120h glycerol feeding as compared to 1.10mg/ml in the control. The production also increased with the span of feeding amino acids and reached a maximum of 1.31 and 1.86mg/ml with feeding arginine and threonine, respectively in 120h. There was an overall increase of 18% and 9% in clavulanic acid production with arginine and threonine feeding as compared to the respective controls (1.10 and 1.70mg/ml, respectively). 相似文献
40.
Ediriweera PS Chandana Yasuhiro Maeda Akihiko Ueda Hiroshi Kiyonari Naoko Oshima Mako Yamamoto Shunya Kondo Junseo Oh Rei Takahashi Yoko Yoshida Satoshi Kawashima David B Alexander Hitoshi Kitayama Chiaki Takahashi Yasuhiko Tabata Tomoko Matsuzaki Makoto Noda 《BMC developmental biology》2010,10(1):1-13