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21.
Henrika G. M. Tiedink Laura H. J. De Haan Wim M. F. Jongen Jan H. Koeman 《Cell biology and toxicology》1991,7(4):371-386
4-chloro-methoxyindole is a naturally occurring compound in Vicia faba which can easily react with nitrite to form a N-nitroso compound. In this in vitro study, the potential genotoxic effects of nitrosated 4-chloro-6-methoxyindole and its structural analogue 4-chloroindole were evaluated for the first time by using both Salmonella and Chinese hamster V79 cells. Additionally, the inhibition of gap junctional intercellular communication in V79 cells by these compounds was determined; this is a validated parameter for tumor-promoting activity. Most assays were also performed with nitrosated indole-3-acetonitrile, a naturally occurring compound in brassicas. Both nitrosated chloroindoles were highly mutagenic to Salmonella typhimurium TA100 without the need of exogenous metabolic activation and were potent inducers of Sister Chromatid Exchanges. Nitrosated indole-3-acetonitrile generated the same effects, although at much higher concentrations. Equivocal results were obtained for the nitrosated chloroindoles in a forward mutation assay using the hypoxanthine guaninephosphoribosyltransferase locus. All nitrosated indole compounds significantly inhibited gap junctional intercellular communication. These results indicate that nitrosated chloroindoles and nitrosated indole-3-acetonitrile should be considered as mutagens and agents with potential tumor-promoting capacity.Abbreviations BrdU
5-bromo-2-deoxyuridine
- 4Cl
4-chloroindole
- 4C6MI
4-chloro-6-methoxy-indole
- DMSO
dimethyl sulfoxide
- EBSS
Earle's balanced salt solution
- EMS
ethyl methanesulfonate
- GJIC
gap junctional intercellular communication
- HBSS
Hanks balanced salt solution
- HGPRT
hypoxanthine guaninephosphoribosyl transferase
- I3A
indole-3-acetonitrile
- MNNG
1-methyl-1-nitroso-3-nitroguanidine
- NOC
N-nitroso compounds
- NQO
4-nitroquinolone-N-oxide
- SCE
sister chromatid exchange
- 6TG
6-thioguanine
- TPA
12-O-tetradecanoylphorbol-13-acetate 相似文献
22.
Behavioural responses of two small ermine moth species (Lepidoptera: Yponomeutidae) to plant constituents 总被引:1,自引:0,他引:1
Wim Van Drongelen 《Entomologia Experimentalis et Applicata》1980,28(1):54-58
On the basis of electrophysiological screening of lateral and medial styloconic sensilla of caterpillars of Yponomeuta species, several hypotheses concerning behavioural effects of plant constituents can be posed (Van Drongelen, 1979). Feeding experiments have been carried out with intact larvae of Y. cagnagellus (Hb.) and Y. evonymellus (L.). Both species display neural responses to dulcitol, phloridzin and prunasin. Leaf discs of the host plants of these species were modified using these three constituents and effects were studied in choice and non-choice situations. Dulcitol appears to stimulate food intake of both species, whereas phloridzin acts as a deterrent exclusively in a choice situation. Prunasin inhibits feeding of Y. cagnagellus in a choice situation, but Y. evonymellus does not show a reaction to this compound at the concentration applied. Neural mechanisms probably underlying these behaviours are discussed.
Supported by the Foundation for Fundamental Biological Research (BION), subsidized by the Netherlands Organization for the Advancement of Pure Research (ZWO). 相似文献
Zusammenfassung Aufgrund elektrophysiologischer Versuche mit lateralen und medialen Sensilla styloconica von Yponomeuta-Arten können mehrere Hypothesen über Verhaltenseffekte von Pflanzenbestandteilen aufgestellt werden (Van Drongelen, 1979). Y. cagnagellus und Y. evonymellus zeigen neurale Reaktionen auf Dulcitol, Phlorizin und Prunasin.Es wurden Frassexperimente mit intakten Raupen beider Arten durchgeführt. Blattscheiben der Wirtspflanzen wurden mit den genannten Stoffen modifiziert, und die Effekte wurden in Wahl- und Nichtwahlversuchen studiert. Dulcitol scheint die Futteraufnahme beider Arten anzuregen, während Phlorizin als Abhaltestoff wirkt und zwar nur in einer Wahlsituation. Prunasin verhindert Fressen bei Y. cagnanellus in einer Wahlsituation, während Y. evonymellus auf diesen Stoff in der geprüften Konzentration nicht reagiert. Neurale Mechanismen, welche wahrscheinlich diesem Verhalten zugrunde liegen, werden diskutiert.
Supported by the Foundation for Fundamental Biological Research (BION), subsidized by the Netherlands Organization for the Advancement of Pure Research (ZWO). 相似文献
23.
Summary Soluble enzymes were immobilized and visualized by polyacrylamide gel slabs, impregnated with the incubation medium including auxiliairy enzymes. The method has several advantages over existing techniques which make use of gel films or a semipermeable membrane. The diffusion of tissue compounds is effectively limited, while auxiliary enzymes may be operative. Moreover the viscosity of the medium is temperature-independent so that the incubation temperature can be varied.To demonstrate the suitability of the method glycerol-3-phosphate dehydrogenase, lactate dehydrogenase, glucose-6-phosphate dehydrogenase, hexokinase, phosphoglucomutase and aldolase were visualized in human or rat skeletal muscle. Cytosolic and mitochondrial glycerol-3-phosphate dehydrogenase were both visualized in the absence of added NAD+ and menadione.For the visualization of ATP producing enzymes, like creatine kinase and pyruvate kinase, the method is not suitable. 相似文献
24.
Harshad S. Ugamraj Kevin Dang Laure-Hlne Ouisse Benjamin Buelow Eduardo N. Chini Giulia Castello James Allison Starlynn C Clarke Laura M. Davison Roland Buelow Rong Deng Suhasini Iyer Ute Schellenberger Sankar N. Manika Shipra Bijpuria Astrid Musnier Anne Poupon Maria Cristina Cuturi Wim van Schooten Pranjali Dalvi 《MABS-AUSTIN》2022,14(1)
25.
Hanne Steel Freija Verdoodt Andrea Čerevková Marjolein Couvreur Pamela Fonderie Tom Moens Wim Bert 《Invertebrate Biology》2013,132(2):108-119
Nematodes are omnipresent in composts and are active in virtually all stages of the composting process. Major shifts in species composition, life strategies, and feeding behavior occur during the composting process. Due to the heat peak, nematodes can be virtually absent, but several taxa appear immediately when the temperatures drop. These comprise both taxa present before the heat peak and new taxa. However, it is not known how nematodes populate the compost. In this study, we aimed to assess the survival and colonization capacity of nematodes in compost. Our results showed that composting processes inaccessible to insects or not in contact with soil did not significantly influence nematode succession during composting. However, differences between treatments were found for some specific taxa (i.e., for Acrostichus sp., Neodiplogasteridae sp., Nygolaimoides sp., and Rhabditidae sp. 1), illustrating the importance of insects for the dispersal of nematodes to compost. Experiments in the lab with the blue bottle fly as a possible carrier demonstrated actual transport of nematodes isolated from compost by the fly (i.e., Halicephalobus cfr. gingivalis, Diploscapter coronatus, Diplogasteritus sp., Acrostichus sp., and Mesorhabditis sp.). Juveniles and dauer stages of Aphelenchoides sp., Panagrolaimus sp., and rhabditids survived an experimentally induced temperature peak, while members of Tylenchidae did not. In conclusion, our results indicate that the rapidly changing nematode community in compost is the result of both differential survival and colonization capacities. 相似文献
26.
Saskia Vanderhaegen Marcus Fislage Katarzyna Domanska Wim Versées Els Pardon Vittorio Bellotti Jan Steyaert 《Protein science : a publication of the Protein Society》2013,22(10):1349-1357
To investigate early intermediates of β2‐microglobulin (β2m) amyloidogenesis, we solved the structure of β2m containing the amyloidogenic Pro32Gly mutation by X‐ray crystallography. One nanobody (Nb24) that efficiently blocks fibril elongation was used as a chaperone to co‐crystallize the Pro32Gly β2m monomer under physiological conditions. The complex of P32G β2m with Nb24 reveals a trans peptide bond at position 32 of this amyloidogenic variant, whereas Pro32 adopts the cis conformation in the wild‐type monomer, indicating that the cis to trans isomerization at Pro32 plays a critical role in the early onset of β2m amyloid formation. 相似文献
27.
Enrichment and characterization of marine anammox bacteria associated with global nitrogen gas production 总被引:2,自引:0,他引:2
van de Vossenberg J Rattray JE Geerts W Kartal B van Niftrik L van Donselaar EG Sinninghe Damsté JS Strous M Jetten MS 《Environmental microbiology》2008,10(11):3120-3129
Microbiological investigation of anaerobic ammonium oxidizing (anammox) bacteria has until now been restricted to wastewater species. The present study describes the enrichment and characterization of two marine Scalindua species, the anammox genus that dominates almost all natural habitats investigated so far. The species were enriched from a marine sediment in the Gullmar Fjord (Sweden) using a medium based on Red Sea salt. Anammox cells comprised about 90% of the enrichment culture after 10 months. The enriched Scalindua bacteria displayed all typical features known for anammox bacteria, including turnover of hydrazine, the presence of ladderane lipids, and a compartmentalized cellular ultrastructure. The Scalindua species also showed a nitrate-dependent use of formate, acetate and propionate, and performed a formate-dependent reduction of nitrate, Fe(III) and Mn(IV). This versatile metabolism may be the basis for the global distribution and substantial contribution of the marine Scalindua anammox bacteria to the nitrogen loss from oxygen-limited marine ecosystems. 相似文献
28.
Wim Meert Lore Cloots Owen Ryan Kathleen Marchal Kevin J. Verstrepen 《Molecular microbiology》2012,86(1):225-239
When grown on solid substrates, different microorganisms often form colonies with very specific morphologies. Whereas the pioneers of microbiology often used colony morphology to discriminate between species and strains, the phenomenon has not received much attention recently. In this study, we use a genome‐wide assay in the model yeast Saccharomyces cerevisiae to identify all genes that affect colony morphology. We show that several major signalling cascades, including the MAPK, TORC, SNF1 and RIM101 pathways play a role, indicating that morphological changes are a reaction to changing environments. Other genes that affect colony morphology are involved in protein sorting and epigenetic regulation. Interestingly, the screen reveals only few genes that are likely to play a direct role in establishing colony morphology, with one notable example being FLO11, a gene encoding a cell‐surface adhesin that has already been implicated in colony morphology, biofilm formation, and invasive and pseudohyphal growth. Using a series of modified promoters for fine‐tuning FLO11 expression, we confirm the central role of Flo11 and show that differences in FLO11 expression result in distinct colony morphologies. Together, our results provide a first comprehensive look at the complex genetic network that underlies the diversity in the morphologies of yeast colonies. 相似文献
29.
Otten LG Sio CF Vrielink J Cool RH Quax WJ 《The Journal of biological chemistry》2002,277(44):42121-42127
Using directed evolution, we have selected an adipyl acylase enzyme that can be used for a one-step bioconversion of adipyl-7-aminodesacetoxycephalosporanic acid (adipyl-7-ADCA) to 7-ADCA, an important compound for the synthesis of semisynthetic cephalosporins. The starting point for the directed evolution was the glutaryl acylase from Pseudomonas SY-77. The gene fragment encoding the beta-subunit was divided into five overlapping parts that were mutagenized separately using error-prone PCR. Mutants were selected in a leucine-deficient host using adipyl-leucine as the sole leucine source. In total, 24 out of 41 plate-selected mutants were found to have a significantly improved ratio of adipyl-7-ADCA versus glutaryl-7-ACA hydrolysis. Several mutations around the substrate-binding site were isolated, especially in two hot spot positions: residues Phe-375 and Asn-266. Five mutants were further characterized by determination of their Michaelis-Menten parameters. Strikingly, mutant SY-77(N266H) shows a nearly 10-fold improved catalytic efficiency (k(cat)/K(m)) on adipyl-7-ADCA, resulting from a 50% increase in k(cat) and a 6-fold decrease in K(m), without decreasing the catalytic efficiency on glutaryl-7-ACA. In contrast, the improved adipyl/glutaryl activity ratio of mutant SY-77(F375L) mainly is a consequence of a decreased catalytic efficiency toward glutaryl-7-ACA. These results are discussed in the light of a structural model of SY-77 glutaryl acylase. 相似文献
30.
Twelve new species of Polycystididae Graff, 1905 are described from the Australian east coast. Nine of them could not be placed
in any of the existing genera, and therefore six new genera are erected. Alchoides n. gen. differs from all other polycystidid genera by the presence of a bundle of glands that opens into the distal part
of the male atrium (accessory vesicle type V). Two species are included in the genus, A. alchoides n. sp. and A. dittmannae n. sp., which differ from each other in the shape of the stylet. Ametochus gehrkei n. gen n. sp. can be distinguished from other polycystidids by the presence of a prostate vesicle type III associated with
a prostate stylet type III, combined with the presence of an accessory stylet type III, while a prostate stylet type II is
lacking. Typical for Arrawarria inexpectata n. gen n. sp. is the combined presence of an armed cirrus with a prostate vesicle type II connected to a prostate stylet
type II. Two species are assigned to the new genus Duplexostylus n. gen.: D. rowei n. sp. and D. winsori n. sp. These two species have two unique features: a prostate vesicle type IV directly connected to a prostate stylet type
III and an asymmetrical septum that surrounds the proximal part of the male atrium. They can be distinguished from each other
by differences in the detailed construction of their stylets. Two new species are placed in the new genus Stradorhynchus n. gen.: S. caecus n. sp. and S. terminalis n. sp. They have unpaired gonads and a prostate vesicle type IV connected to a prostate stylet type IV, which combination
of characters makes them unique within the Polycystididae. The two species differ from each other in the shape and size of
the stylet. Triaustrorhynchus armatus n. gen., n. sp. is the first species of the Polycystididae to have three types of stylet in the male atrium: a prostate stylet
type II, a prostate stylet type III and an accessory stylet type III. Three new species could be placed in existing genera:
Cincturorhynchus monaculeus n. sp., Paraustrorhynchus caligatus n. sp. and Polycystis australis n. sp. All three differ from their congeners in the form and dimensions of their stylets. All newly described species are
discussed, giving their similarities and differences with resembling species. Austrorhynchus hawaiiensis Karling, 1977 is reported for the first time in Australia, and the Australian population is compared with populations from
other regions. The presence of Gyratrix hermaphroditus Ehrenberg, 1831, one new species of Paulodora Marcus, 1948 and a new genus of Typhlopolycystidinae Evdonin, 1977 is mentioned. 相似文献