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51.
Jørn Stave Gufu Oba Inger Nordal Nils Chr Stenseth 《Biodiversity and Conservation》2007,16(5):1471-1489
The present study explores traditional ecological knowledge (TEK) of Turkana pastoralists and cultivators in the context of
a riverine forest in northern Kenya. The Turkwel River and its floodplain sustain a thick forest, which is used for grazing
and extraction of non-timber forest products. However, sedentarisation and agricultural expansion have resulted in localised
clear-felling of trees, while river damming has altered the natural flow regime. A series of structured, semi-structured,
and group interviews were combined with a botanical inventory in order to assess the relevance of TEK to ecological research
and forest conservation. Turkana informants gave 102 vernacular names for the 113 woody species. Of these, 85% had a domestic
or pastoral use among the 105 specific uses that were described. Ethnobotanical knowledge was relatively homogenous and not
related to age, gender, or source of livelihood. The informants had in-depth knowledge of some key ecological processes. The
conceived threats to forest survival were primarily cultivation and permanent settlements, while the effects of river damming
and livestock grazing were disputed. A claimed decline in rainfall was confirmed by official data. There is strong evidence
that TEK could be used to generate hypotheses for research and to design sustainable conservation strategies. A revised version
of the indigenous system of tree management should be incorporated into the official forestry policy in order to resolve future
conflicts between pastoralists and cultivators. 相似文献
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55.
Thuesen MH Nørgaard A Hansen AM Caspersen MB Christensen HE 《Protein expression and purification》2003,27(1):175-181
The gene of the di-heme protein cytochrome c(4) from Pseudomonas stutzeri was expressed in Pseudomonas putida. High-yield expression of the protein was achieved by high-cell-density fed-batch cultivation using an exponential glucose feeding strategy. The recombinant cytochrome c(4) protein was purified to apparent homogeneity and analyzed by electronic absorption spectroscopy, nanoflow electrospray ionization time-of-flight mass spectrometry, and electrochemistry. Cyclic voltammograms and UV-vis electronic absorption spectra were indistinguishable from the equivalent data of native P. stutzeri cytochrome c(4). Furthermore, the calculated and experimentally determined molecular masses of recombinant cytochrome c(4) were identical. Biochemical characterization of both wild-type and mutant derivatives of the protein will be greatly enhanced and facilitated by the described high-yield fermentation and rapid isolation procedure. 相似文献
56.
Background
Head and neck cancers (HNC) are relatively common and often very serious diseases in both dogs and humans. Neoplasms originating in the head and neck region are a heterogeneous group. HNC often has an unfavourable prognosis and the proximity of the tissue structures renders extirpation of tumours with sufficient margins almost incompatible with preservation of functionality. In humans oral malignant melanoma (OMM) is extremely rare, but represents a particular challenge since it is highly aggressive as is the canine counterpart, which thus may be of interest as a spontaneous animal model. 相似文献57.
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Following the midcyclic gonadotropin surge, PACAP is transiently expressed for approximately 12 h in the cyclic adult rat ovary. PACAP is observed in granulosa/lutein cells of the large mature follicles destined to ovulate and is believed to be a regulator of acute progesterone production and luteinization in these follicles. PACAP is also observed in solitary theca cells of immature follicles and in interstitial glandular cells intimately surrounding immature follicles. To examine if PACAP could be involved in the process of cyclic recruitment of such immature follicles, we primed immature granulosa cells from prepubertal ovaries with PACAP (1 nM and 100 nM) for 12 h. The treatment significantly stimulated the subsequent 24 h FSH-induced estradiol production (2.2 and 2.4 fold, respectively). The response seemed to be caused by a stimulation of aromatase activity. Estradiol production induced by testosterone was increased 2.4 and 2.6 fold, respectively, whereas functional FSH-receptors (cAMP production following FSH stimulation) or spontaneous apoptosis (immunohistochemical detection of DNA fragments) was unaffected. We conclude that PACAP priming of immature rat granulosa cells for 12 h increases subsequent FSH induced estradiol production and that PACAP could be involved in the cyclic recruitment of immature follicles in the adult rat ovary. 相似文献
60.
High resolution NMR for studying lipid hydrolysis and esterification in cod (Gadus morhua) gonads 总被引:2,自引:0,他引:2
High resolution NMR was applied to study biochemical changes of lipids in cod (Gadus morhua) gonads during 7 days storage at 4 degrees C. Changes were observed in the (13)C and (1)H resonances of cholesterol which were due to esterification of fatty acids at the hydroxyl position in roe and milt. Furthermore, the (13)C NMR spectra showed that the lipolytic changes in milt and roe where different. New resonances appeared during storage, due to formation of specific free fatty acids, with the corresponding changes in resonances of the esterified carbonyls and glycerols. The highly unsaturated n-3 fatty acids were hydrolysed from the sn-1 and sn-2 position of both phosphatidylcholine and phosphatidylethanolamine in milt. The lipolytical changes in roe were less prominent compared to the changes in milt, however significant levels of sn-1-lysophospholipids was detected both in roe and milt. The current data demonstrate that high resolution NMR may be a suitable method to non-destructively study hydrolysis and esterification reactions occurring in heterogeneous marine lipids in a one step procedure. 相似文献