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Peter J. K. Kuppen Alexander M. M. Eggermont Andreas Marinelli Emile de Heer Cornelis J. H. van de Velde Gert Jan Fleuren 《Cancer immunology, immunotherapy : CII》1991,33(1):28-32
Summary The role of 2-mercaptoethanol and indomethacin in the induction of lymphokine-activated killer (LAK) activity by interleukin-2 (IL-2) in rat splenocyte cultures was investigated. Spleens from 4-month-old male rats of five different strains were tested. Splenocytes were cultured for 3–5 days in the presence of IL-2 (1000 U/ml) and LAK activity was assessed by 4-h51Cr release assays with P815 and YAC-1 cells as targets. LAK activity could be induced by IL-2 in splenocytes from all rat strains, but only when 2-mercaptoethanol was present in the culture medium. Optimal LAK activity was induced when the 2-mercaptoethanol concentration in splenocyte cultures was at least 5 µM. Different rat strains showed differences in levels of in vitro induction of LAK activity. In the presence of 2-mercaptoethanol the level of LAK activity induced by IL-2 was high in BN and Lewis rats, intermediate in Wistar and Wag rats, and low in DZB rats. In the absence of 2-mercaptoethanol no or minimal LAK activity was induced. Furthermore we observed that addition of 50 µm indomethacin to the culture medium in the presence of 2-mercaptoethanol augmented the induction of LAK activity to some extent. In the absence of 2-mercaptoethanol, addition of indomethacin resulted only in low levels or no induction of LAK activity. We conclude that for optimal induction of LAK activity by IL-2 in rat splenocyte cultures 2-mercaptoethanol is essential, while indomethacin can only marginally further improve this induction. 相似文献
6.
Across the world there is a prevailing view that freshwater algae are cosmopolitan. The notion has seldom been tested and
is unlikely to be true in genetic terms. Nonetheless, some morphospecies of several groups of algae do have a worldwide distribution.
Others have restricted distributions and may be regarded as endemic to a region. However there is always the possibility that
they will be discovered in far away places. Australia has a rather large element of endemicity in its algal flora. From the
early days of Australian phycology many new genera and species of freshwater algae have been described. Some are of such distinctive
appearance or novelty as to be regarded as ‘flagship’ taxa. There is little doubt about their endemicity and their existence
increases the probability of less-distinguished species also being endemic. The degree of endemicity is probably masked by
the ‘force-fitting’ of European names to Australian species.
Some Australian endemics are robust and are widely distributed in a variety of types of water body. Others, the frail endemics,
the ones of greatest novelty and phylogenetic significance, have a very restricted range with their strongholds in dystrophic
coastal lagoons where tracts or remnant patches of native vegetation survive. Their survival and the conservation of their
biodiversity depends on recognition of the significance of coastal lagoons and swamps. 相似文献
7.
Resumé Quinze nouvelles espèces de Monogènes Dactylogyridae sont décrites chez quinze espèces deBarbus (Teleostei, Cyprinidae) appartenant aux sous-genresB. (Barbus) etB. (Labeobarbus) en Afrique du Nord. Les barbeaux examinés proviennent des différents bassins hydrographiques du Maroc et d'une localité nommée Hamman Bourgiba en Tunisie. Dans cette dernière région, le genreBarbus n'est représenté que par une seule espèce:Barbus (B.) callensis. Au Maroc, on en dénombre actuellement quatorze dont quatre appartiennent au sous-genreLabeobarbus: il s'agit deBarbus (L.) fritschii; B. (L.) harteti; B. (L.) paytonii etB. (L.) reinii. Les dix espèces appartenant au sous-genreBarbus sont:Barbus (B.) figuiensis; B. (B.) ksibi; B. (B.) lepineyi; B. (B.) magniatlantis; B. (B.) massaensis; B. (B.) moulouyensis; B. (B.) nasus; B. (B.) pallaryi; B. (B.) setivemensis etB. (B.) issenensis.Chaque sous-genre possède son propre pool parasitaire, à l'exception deDactylogyrus marocanus n. sp., recontré sur des espèces appartenant aux deux sous-genres (B. (L.) fritschii, B. (L.) paytonii, B. (L.) harteti, B. (L.) reinii, B. (L.) nasus, B. (B.) setivimensis, B. (B.) ksibi). Sur les cinqDactylogyrus parasitant lesLabeobarbus, trois présentent une spécificité stricte vis à vis de leur hôte. Il s'agit deDactylogyrus reinii n. sp. surB. (L.) reinii; D. volutus n. sp. etD. zatensis n. sp. surB. (L.) fritschii. Les espècesD. oumiensis n. sp. etD. kulindrii n. sp. présentent une spécifité stenoxène et parasitent respectivementB. (L.) harteti, B. (L.) paytonii, B. (L.) reinii etB. (L.) fritschii, B. (L.) reinii.Nous avons recontré neufDactylogyrus chez les poisson-hôtes appartenent au sous-genreBarbus. Six d'entre eux ont une spécificité oïoxène; ce sont:D. guirensis n. sp.,D. atlasensis n. sp. etD. draaensis n. sp. surB. (B.) pallaryi; D. borjensis n. sp. surB. (B.) nasus etD. heteromorphus n. sp. etD. tunisiensis n. sp. surB. (B.) callensis. Les trois autres parasites ont un spectre d'hôtes plus large. Il s'agit deD. ksibii n. sp. recontré chezB. (B.) ksibi, B. (B.) setivimensis etB. (B.) magniatlantis; D. ksibioïdes n. sp. recontré chezB. (B.) setivimensis etB. (B.) moulouyensis. L'espèceD. fimbriphallus n. sp. stenoxène, se recontre chez les poisson-hôtes du versant Sud de l'Atlas et de la façade méditerranéenne à savoir:B. (B.) figuiensis, B. (B.) lepineyi, B. (B.) massaensis, B. (B.) moulouyensis, B. (B.) pallaryi etB. (B.) issenensis.Le rôle des Dactylogyridae en tant que marqueurs biogéographiques, phylogénétiques et taxonomiques est discuté à partir de la composition spécifique des communautés de Monogènes rencontrés et de leurs différents types morphologiques.
Fifteen new species of the Dactylogyridae (Monogenea) parasitic on fifteen species of barbels (Barbus) from North Africa (Teleostei, Cyprinidae) are described. The fishes studied belong to two subgenera,B. (Labeobarbus) andB. (Barbus), collected from various hydrographical basins of Morocco and from the Hamman Bourgiba locality in Tunisia. In the latter area, the genusBarbus is represented by onlyBarbus (Barbus) callensis. In Morocco, fourteen species are listed, four of which belong to the subgenusLabeobarbus; these areBarbus (L.) fritschii; B. (L.) harteti; B. (L.) paytonii andB. (L.) reinii. The other ten species belong to the subgenusBarbus: these areBarbus (B.) figuiensis; B. (B.) ksibi; B. (B.) lepineyi; B. (B.) magniatlantis; B. (B.) massaensis; B. (B.) moulouyensis; B. (B.) nasus; B. (B.) pallaryi; B. (B.) setivimensis andB. (B.) issenensis. Each of the two subgenera has its unique parasitic fauna, except forDactylogyrus marocanus n. sp. collected on species belonging to both subgenera (B. (L.) fritschii, B. (L.) paytonii, B. (L.) harteti, B. (L.) reinii, B. (B.) nasus, B. (B.) setivimensis andB. (B.) ksibi). Of the five monogeneans found onLabeobarbus, three appear to be specific to one host: they areDactylogyrus reinii n. sp. onB. (L.) reinii, andD. volutus n. sp. andD. zatensis n. sp. onB. (L.) fritschii. D. kulindrii n. sp. parasitisedB. (L.) reinii andB. (L.) fritschii; andD. oumiensis n. sp. occurred onB. (L.) reinii, B. (L.) paytonii andB. (L.) harteti. NineDactylogyrus species were found in fishes belonging to the subgenusBarbus. Six of them have an oïoxenous specificity: these areD. guirensis n. sp.,D. atlasensis n. sp. andD. draaensis n. sp. onB. (B.) pallaryi; D. borjensis n. sp. onB. (B.) nasus andD. heteromorphus n. sp. andD. tunisiensis n. sp. on(B.) callensis. These other three have a wider range of hosts: they areD. ksibii n. sp. collected fromB. (B.) ksibi, B. (B.) setivimensis andB. (B.) magniatlantis, andD. ksibioïdes n. sp. found onB. (B.) setivimensis andB. (B.) moulouyensis. D. fimbriphallus n. sp. is a characteristic parasite of fishes from the southern side of the Atlas mountains and the Mediterranean coast (B. (B.) figuiensis, B. (B.) lepineyi, B. (B.) massaensis, B. (B.) moulouyensis, B. (B.) pallaryi andB. (B.) issenensis).The role of dactylogyrids as biogeographical phylogenetic and taxonomic indicators is discussed in relation to the specific structure of the monogenean communities and the different morphological types found.相似文献
8.
Analysis of phytochrome- and ABA-deficient mutants suggests that ABA degradation is controlled by light in Nicotiana plumbaginifolia 总被引:6,自引:2,他引:4
Yvan Kraepiel Philippe Rousselin Bruno Sotta Lucien Kerhoas Jacques Einhorn Michel Caboche Emile Miginiac 《The Plant journal : for cell and molecular biology》1994,6(5):665-672
The phytochrome chromophore-deficient mutant, pew1, of Nicotiana plumbaginifolia exhibited decreased germination and slower dehydration of detached leaves during water stress as compared with the wild-type. These physiological processes are controlled by abscisic acid (ABA) and we examined, therefore, whether phytochrome plays a specific role in the regulation of ABA metabolism using the pew1 mutant. The ABA contents of mature seeds and young leaves were analysed and in both cases mutant material was found to contain higher amounts of ABA as compared with the wild-type. This indicates that the phytochrome activation can lead to a decrease of the ABA level in the wild-type plant. The role of phytochromes was investigated in greater detail using the ABA-deficient mutant aba1 of N. plumbaginifolia exhibiting an early and synchronous germination. This mutant accumulates at very high levels a metabolite derived from a precursor (ABA-aldehyde) in the ABA biosynthetic pathway. The first biochemical characterization of this molecule, which corresponds to the glucose-conjugated ABA-alcohol (ABA-AG) is described. A pew1-aba1 double mutant exhibiting both an etiolated growth and early germination was also obtained. The comparable accumulation of ABA-AG in the pew1-aba1 double mutant as compared with the aba1 mutant allowed the proposition that, in a wild-type plant, the phytochrome-mediated light signal enhances ABA degradation rather than inhibits its biosynthesis. 相似文献
9.
Emile CL. Marnette Harm Houweling Herman Van Dam Jan Willem Erisman 《Biogeochemistry》1993,23(2):119-144
The chemical composition of surface waters of two Dutch moorland pools and of incident precipitation, was monitored from 1982
to 1990. For this period, sulfur and water budgets were calculated using a hydrochemical model developed for well-mixed non-stratifying
lakes. Total atmospheric deposition of S decreased significantly after 1986 at both locations. A model describing the sulfur
budget in terms of input, output and reduction/oxidation processes predicted a fast decrease of pool water SO4
2− concentrations after a decrease of atmospheric input. However, SO4
2− concentrations in the surface water was lowered only slightly or remained constant. Apparently a source within the lake caused
the unexpectedly high SO4
2− concentrations. The possible supply of SO4
2− from the sediment through regulation by (K-)Al-SO4 containing minerals or desorption of SO4
2− from positively charged surfaces in the sediment was evaluated. Solubility calculations of pore water with respect to alunite,
basaluminite and jurbanite indicated that SO4
2− concentration was not regulated by these minerals. It is suggested here (1) that desorption of SO4
2− from peaty sediments may account for the estimated SO4
2− supply provided that the adsorption complex is periodically recharged by partial oxidation of the upper bottom sediments
and (2) that because of exposure of a part of the pool bottom to the atmosphere during dry summers and subsequent oxidation
of reduced S, the amount of SO4
2− may be provided which complements the decreasing depositional SO4
2− input. In future research these two mechanisms need to be investigated. 相似文献
10.
Isabelle Goebel-Tourand Marie-Claude Mauro Lucienne Sossountzov Emile Miginiac Alain Deloire 《Plant Cell, Tissue and Organ Culture》1993,33(1):91-103
In an effort to understand the causes of arrest of somatic embryo development, generally observed in grapevine (Vitis sp.), histological studies were undertaken, using two cultivars (CH76 and 41B) which differ in their ability to develop into plants. Embryos with a high conversion rate (70%; CH76) formed a well-structured and functional shoot apex between two thread-like cotyledons. In contrast, embryos with a low conversion rate (10%; 41B) formed a normal root apex but lacked a well-structured shoot apex and developed a wide range of aberrant forms in the intercotyledonary area: uncontrolled cellular proliferation, formation of adventitious buds, over-growth of cotyledonary or leaf meristems. ABA increased the conversion rate of 41B embryos from 10% to 20%, but failed to improve embryo morphology. Zeatin and BAP promoted growth of 41B somatic embryos, but generated a high level of abnormalities and failed to improve conversion rate. Applied in combination with ABA, these PGRs increased the frequency of cotyledonary embryos, but decreased the conversion rate. 相似文献