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1.
Abstract Lipopolysaccharides (LPS) isolated from Legionella pneumophila serogroup 12 strains were studied for their usefulness as epidemiological markers. L. pneumophila serogroup 12 was cultured from 3 patients infected at home, in another hospital and abroad, as well as from hot tapwater in their quarters. LPS isolated from these strains showed 2 distinct patterns and 4 different colours in silver-stained polyacrylamide gels. LPS of the first pattern stained dark-grey, those of the second pattern were either orange-brown, dark-brown or black-brown. These differences were reproducible. By comparing patterns and colours of isolated LPS molecules, similarity could be demonstrated between strains from the first patient and from hot water in his home, as well as between strains from the second patient and from hot water in the hosoptal where he became infected. None of the strains displayed LPS of the same colour as that of the third patient, who was admitted with pneumonia from Spain. Patterns and colours of LPS isolated from L. pneumophila serogroup 12 in ilver-stained gels can be used as a marker system in epidemiological studies.  相似文献   

2.
Recent advances in the fight against leishmaniasis with natural products   总被引:4,自引:0,他引:4  
The active compounds obtained from some medicinal plants used traditionally worldwide for the treatment of leishmaniasis are reviewed. Among these active molecules, described in recent literature are quinoline alkaloids such as alkyl-2 quinoline and aryl-2 quinoline from Galipea longiflora, isoquinoline alkaloids such as isoguattouregidine from Guatteria foliosa, indole alkaloids such as conodurine and gabunine from Pescheiera van heurkii, terpenes such as jatrogrossidione from Jatropha grossidentata, acetogenins such as senegalene from Annona senegalensis and lignans such as (+)nyasol from Asparagus africanus. Other natural compounds with antileishmanial activity are coumarins, chalcones, lactones, tetralones and saponins. Some of them are known antiprotozoal natural products. These compounds could be used as templates to discover new and effective drugs against leishmaniasis.  相似文献   

3.
The mRNA coding for the ACTH-β-lipotropin precursor from a human ectopic ACTH-producing thymic carcinoid was identified by blot hybridization analysis with the bovine cDNA as a probe. The mRNA from the tumor had the same length (approximately 1,100 nucleotides) as that from the human pituitary. An additional hybridization-positive RNA species of a larger size was found in the tumor. Cell-free translation of the mRNA from the tumor as well as from the pituitary yielded a product with an apparent molecular weight of 38,000 that was reactive both with antibody to ACTH and with antibody to β-endorphin.  相似文献   

4.
The early Neolithic sites of La Lámpara and La Revilla del Campo in the Meseta Norte (Northern Meseta) plateau in central Spain produced evidence for early agriculture from the last third of the 6th millennium B.C. The hulled wheats Triticum monococcum (einkorn) and T. dicoccum (emmer) were identified from carbonised plant remains as well as from imprints in pottery and daub. Single finds of charred remains of Hordeum vulgare (barley), Papaver somniferum/setigerum (poppy) and Linum usitatissimum (linseed) indicated other cultivated crops. The wild plants mainly indicated arable weeds, partly from less fertile soils, and garrigue vegetation from poor pastures. The spectrum of crops from the Ambrona sites was compared to other inner Iberian sites as well as to Mediterranean sites. Sediment samples as well as mineral crusts from graves were analysed from the Neolithic tumulus of La Peña de la Abuela. Its diachronic collective burials had originated from a period of time during the first third of the 4th millennium B.C. Probably no crops, but many green vegetative parts of pine, oak, and juniper had been used as funeral gifts. Oak cupula development indicated early summer activities in the grave-mound. Wickerwork made of willow was used for embedding the dead bodies.  相似文献   

5.
The effects of oils and oil components on algae: A review   总被引:1,自引:0,他引:1  
Plate structure analysis of the bloom-forming Peridinium of Lake Kinneret (previously identified as P. cinctum fa. westii) established its identity as P. gatunense. Peridinium cinctum was not observed. Material from different years and periods of the bloom, as well as specimens from cultures and P. gatunense from Lago Cristalino (Brazil), were studied using light and scanning electron microscopy. Peridinium gatunense from Lake Kinneret showed slight differences of the plate pattern as compared with specimens from other localities.  相似文献   

6.
Ribulosebisphosphate carboxylase molecules from over 50 species of angiosperms and gymnosperms have been compared by quantitative microcomplement fixation, using antisera prepared against tobacco and spinach enzymes. There were close antigenic similarities between tobacco enzyme, enzymes from other members of the Solanaceae, and enzymes from members of the Nolanaceae, Cuscutaceae, and Convolvulaceae. There were relatively close similarities between spinach enzyme and enzymes from two other members of the Chenopodiaceae. There were relatively great differences between tobacco enzyme, spinach enzyme, and most other enzymes tested. The enzymes from most of the angiosperms tested were as different from tobacco enzyme and almost as different from spinach enzyme as were the enzymes from the gymnosperms.  相似文献   

7.
Research to develop tools to assess the ecological status of phytobenthos, as required in Annex V of the European Union Water Framework Directive, has focussed largely on diatoms. Diatoms are often the most abundant and diverse group of algae within the phytobenthos and have been used widely for other monitoring purposes. However, there is little empirical justification for the use of diatoms as proxies for the wider phytobenthos. In this paper, we re-examine an existing dataset compiled largely from littoral samples from standing waters in the English Lake District and compared transfer functions for total phosphorus, dissolved inorganic carbon, conductivity and calcium concentration generated from diatoms and non-diatoms separately and together. The results show that transfer functions generated from diatoms alone are as powerful as transfer functions generated from diatoms and non-diatoms combined, while transfer functions generated from non-diatoms alone are less effective. These results provide support for the use of diatoms as proxies for phytobenthos when ecological status is being assessed. Handling editor: J. Saros  相似文献   

8.
Abstract

In the past, fossilised dinosaur eggshells have been extensively documented from the Upper Cretaceous Lameta Formation of Central India and as many as nine oospecies are known at present from this formation. Compared to this, only one dinosaur oospecies has been described from the Cretaceous succession of the Cauvery Basin. However, the first fossil egg from India, identified as a chelonian egg, was documented from the Aptian – Albian Karai Formation of the Cauvery Basin in 1957. Following this, a solitary titanosaurid dinosaur egg was described from the Upper Cretaceous (Lower Maastrichtian) Kallankuruchhi Formation, Cauvery Basin in 1996. More recently, we have recovered isolated eggshell fragments from the marine part of the Upper Cretaceous (Late Maastrichtian) Kallamedu Formation. Based on eggshell morphology, microstructure and ultrastructure, these eggshell fragments are assigned to the oospecies Fusioolithus baghensis. The new find from the Cauvery Basin is important from palaeobiogeographic point of view as the oofamily Fusioolithidae is found in the Upper Cretaceous strata of India, France, Argentina and Morocco. Based on the common occurrence of similar oospecies in South America, Africa, Europe and India, a Late Cretaceous palaeobiogeographic connection between India and South America as well as Europe via Africa is suggested.  相似文献   

9.
Taking advantage of the effects on DNA secondary structure of two DNA-intercalators,ethidium bromide and chloroquine,we used each of them to treat nuclei from both mature erythrocytes and reticulocytes of chicken,as an alternative approach to study the relationships between DNA secondary structure,nuclear proteins and chromatin structure.We presented results of differential extraction of nuclear proteins from nuclei with DNA-intercalators,as well as preliminary characterization of these proteins.A 45kd protein is the major component in fractions extracted by both intercalators from nuclei from either mature erythrocytes or reticulocytes and seems to be a DNA-binding protein.Furthermore,from current concepts of functional aspects of DNA conformation and structural heterogeneity in chromatin and nuclear proteins,we have discussed both the significance of our results as well as technical aspects of this approach.  相似文献   

10.
【目的】不同风化程度钾长石表面矿物分解细菌生物多样性研究将有助于了解矿物生物风化、生物成矿和土壤形成的演化规律和机理。【方法】采用纯培养法自南平钾矿区高、中、低风化度钾长石以及矿区土壤样品中分离矿物分解细菌,通过摇瓶释硅实验比较不同菌株分解矿物能力,采用16SrDNA限制性酶切多态性分析(Amplified rDNA Restriction Analysis,ARDRA)研究了供试菌株的遗传多样性。【结果】分离筛选到35株生长良好的矿物分解细菌,与对照相比,接菌处理发酵液中有效硅增加了101~206%;所有供试菌株可分为11个OTU,分别属于5个门,6个科,7个属。多数菌株(74%)属于γ-变形杆菌纲(γ-Proteobacteria)。泛菌属(Pantoea),沙雷氏菌属(Serratia),假单胞菌属(Pseudomonas)为优势种群。【结论】南平钾矿区矿物分解细菌具有丰富的微生物种群多样性,且γ-变形杆菌纲(γ-Proteobacteria)细菌在钾长石风化过程中可能起了重要的作用。  相似文献   

11.
It is commonly accepted that dasyurids (Marsupialia: Dasyuridae) radiated in the late Miocene or early Pliocene in response to a drying trend in Australia's climate as evidenced from the high diversity of dasyurids from modern arid environments compared with Miocene rainforest assemblages. However, mid‐Pleistocene dasyurid assemblages from cave deposits at Mt Etna, Queensland are more diverse than any previously known from rainforest habitats. New taxa will be described elsewhere, but include three new genera as well as new species of Dasyurus, Antechinus and Phascogale. Comparison of dasyurids from Mt Etna sites that are interpreted as rainforest palaeoenvironments with fossil and extant assemblages indicate that they are at least as diverse as those from modern arid environments. Thus Neogene diversification of dasyurids occurred in both arid and rainforest habitats, but only the former survived continuing aridification. Hence, aridification cannot be invoked for the diversification of all dasyurid lineages.  相似文献   

12.
Parakiefferiella lagorum spec. nov. from central Chile is described and figured as male, female and pupa; P. hernandezi spec. nov. from south Chile and P. strixinorum spec. nov. from southeast Brazil as males and pupae; and P. wardorum spec. nov. from south Chile, as male only. In addition, an unassociated pupa from south Chile is described and figured. Keys to the Parakiefferiella males and pupae from South America are provided.  相似文献   

13.
14.
Strongman DB  Xu S 《Mycologia》2006,98(3):479-487
Trichomycetes were recovered from the guts of aquatic insect larvae collected from a stream in the Qinling Mountains in western China. These collections included Smittium hecatei, known only from Spain, as well as Smittium simulii and Stachylina penetralis, which appear to be more widely distributed. Caudomyces japonicus, previously recorded only from Japan, also is reported from crane fly larvae (Antocha sp.) from China. We describe three new species, Smittium chinliense from a tipulid host, as well as Smittium naiadis and Smittium nodifixum, both from chironomid larvae. A probable new species of Gauthieromyces was collected in mayfly nymphs and is illustrated but not described here.  相似文献   

15.
Continuous cell lines have been established from spleen cells of patients with confirmed hairy cell leukemia (HCL). One cell line, HCL-Z1, lacks Epstein-Barr virus nuclear antigen (EBNA), grows attached to the substratum and retains typical features of hairy cells as revealed by transmission and scanning electron microscopy. HCL-Z1 differs morphologically from the three other EBNA-positive lymphoblastoid cell lines obtained (HCL-Z2, HCL-Z3, HCL-Z4) as well as from normal spleen cells or lymphocytes. The three lymphoblastoid cell lines derived from HCL patients show similar surface features as a line from a myeloma patient. Therefore, not all cell lines derived from HCL patients may be considered as representative of the patients leukemia cells.  相似文献   

16.
Abstract Extracts of Zymomonas mobilis in the presence of NADPH converted tritium-labelled farnesyl diphosphate (FPP) into squalene, resulting from the activity of squalene synthase, as well as diploptene and diplopterol, derived from further squalene cyclisation. An unidentified isoprenoid representing up to 70% of the conversion products of FPP and different from presqualene alcohol was also formed, even in the absence of NADPH. Addition of squalestatin 1, an inhibitor of squalene synthase, blocked biosynthesis from FPP of the three former triterpenes, in accordance with the role of squalene synthase in their formation, as well as that of the unknown compound.  相似文献   

17.
Sediments and water from the pristine headwaters of the San Marcos River, Texas, USA, as well as swabs from biofilms on the carapace and from the cloacae of 17 musk turtles (Sternotherus odoratus) and one snapping turtle (Chelydra serpentina serpentina) caught at the same site, were analysed for salmonellae by culture and molecular techniques. Whereas enrichment cultures from sediment and water samples were negative for salmonellae in PCR- and in situ hybridization-based analyses, both techniques detected salmonellae after enrichments from both carapace and cloacae of nine (i.e. of 53%) musk turtles. Further characterization of 10 isolates obtained from the enrichment cultures of four selected individuals and confirmed as salmonellae by PCR analysis was achieved by fingerprinting techniques (rep-PCR). The results show differences between individuals and, in one case, variation among isolates from a single individual. All isolates from two individuals displayed identical profiles. These profiles were different from those obtained from the isolates of the third individual, which were, themselves, also identical for all isolates. Salmonellae were much more diverse in samples from the carapace of the last individual with five different rep-PCR profiles retrieved. Serotyping of seven isolates representative for each rep-PCR profile identified all isolates as representing Salmonella enterica subspecies enterica serotype Rubislaw, which demonstrates the presence of different strains of potentially human pathogenic salmonellae naturally occurring on turtles even within pristine environments. The frequent detection of these organisms in biofilms on the carapace opens the door for speculations on the role of this habitat as a reservoir for salmonellae, and on potential implications for turtles acting as a dispersal vector.  相似文献   

18.
The sensitivities of PDE-4 enzymes from smooth muscle and inflammatory cell sources from different species to a range of structurally diverse compounds were compared. All inflammatory cell PDE-4 sources displayed good crosscorrelations in their sensitivity to inhibition by these compounds. Similarly, PDE-4 enzymes from smooth muscle sources were well-correlated; however, there was no crosscorrelation between PDE-4 from smooth muscle sources and those of inflammatory cell sources, possibly reflecting differences in subcellular location of enzymes as well as subtype expression. The present study concludes that PDE-4 preparations from smooth muscle sources as well as those from inflammatory cell sources may be used to model the potential smooth muscle cell relaxing properties and anti-inflammatory properties of a compound in relation to human asthma.  相似文献   

19.
The nutrient media developed in the USSR and CSR for the isolation of campylobacteria are multi-purpose as they enable the isolation of campylobacteria not only from material derived from patients with acute intestinal infection, but also from the internal organs of healthy and diseased animals and poultry as well as from a variety of objects in the environment.  相似文献   

20.
In renal tubules isolated from fed rabbits glycerol is not utilized as a glucose precursor, probably due to the rate-limiting transfer of reducing equivalents from cytosol to mitochondria. Pyruvate and glutamate stimulated an incorporation of [14C]glycerol to glucose by 50- and 10-fold, respectively, indicating that glycerol is utilized as a gluconeogenic substrate under these conditions. Glycerol at concentration of 1.5 mM resulted in an acceleration of both glucose formation and incorporation of [14C]pyruvate and [14C]glutamate into glucose by 2- and 9-fold, respectively, while it decreased the rates of these processes from lactate as a substrate. In the presence of fructose, glycerol decreased the ATP level, limiting the rate of fructose phosphorylation and glucose synthesis. As concluded from the 'cross-over' plots, the ratios of both 3-hydroxybutyrate/acetoacetate and glycerol 3-phosphate/dihydroxyacetone phosphate, as well as from experiments performed with methylene blue and acetoacetate, the stimulatory effect of glycerol on glucose formation from pyruvate and glutamate may result from an acceleration of fluxes through the first steps of gluconeogenesis as well as glyceraldehyde-3-phosphate dehydrogenase. As inhibition by glycerol of gluconeogenesis from lactate is probably due to a marked elevation of the cytosolic NADH/NAD+ ratio resulting in a decline of flux through lactate dehydrogenase.  相似文献   

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