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61.
The bacterial degradation of catechol, 3-methylcatechol, 2,3-dihydroxy-β-phenylpropionic acid, and protocatechuic acid has been studied in detail. From the results obtained a general sequence has been proposed for the microbial oxidation of dihydroxy aromatic compounds. 相似文献
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Bacteria pathogenic to crucifers were isolated from 92% of the eggs from flies of the cabbage maggot, Hylemyia brassicae (Bouché) of a population from rutabaga (Swede; Brassica napus napobrassica) and from 90% of those from a population from Chinese cabbage (Brassica pekinensis). The larvae transmitted the decay-causing bacteria to healthy tissues and aided in the development and spread of the rot. Of bacterial isolates from the interior of surface-sterile puparia, decay was caused by 100% of those from the rutabaga population and 35% of those from Chinese cabbage. Pathogenic cultures were also obtained from 44% of the prepupal linings of the Chinese cabbage population. The light internal contamination of adults at eclosion showed that the flies became contaminated externally from the interior of the puparia.The two populations of H. brassicae studied were contaminated with distinctly different types of bacteria. Erwinia sp., the predominant isolate from the rutabaga population, grew best on rutabaga. It caused a slow necrotic collapse and a dark pigmentation of the tissues, but not a soft-rot. Many different types of bacterial contaminants were associated with the stages of the cabbage maggot from Chinese cabbage. Green pigmenting, non-pathogenic forms were very prevalent. All pathogenic cultures caused some type of soft-rot. Some of these cultures were identified as Pseudomonas sp. and Aerobacter sp.
Approved for publication by the Director of the Wisconsin Agricultural Experiment Station. 相似文献
Zusammenfassung Es wurde die Beziehung zweier Kohlfliegen-Populationen (Hylemyia brassicae Bouché) zu fäulniserregenden Bakterien an Kreuzblütlern in Verbindung mit dem von den Larven verursachten Schaden untersucht. 92 bez. 90% der Eier und 100 bez. 35% der Puparien, die sich an Kohlrüben und Chinakohl entwickelten, trugen pathogene Bakterien. Pathogene Kulturen wurden von 44% der Präpuppen-Häute aus Puparien der Chinakohl-Populationen erhalten. Die Larven vermochten fäulniserregende Bakterien wirksam auf gesunde Gewebe zu übertragen und förderten die Entwicklung und Ausbreitung der Fäule. Beim Schlüpfen waren die Imagines innerlich nicht stark kontaminiert, beschmierten sich aber offenbar äußerlich durch Kontakt mit dem Inneren der Puppengehäuse und der Präpuppen-Häute.Ein als Erwinia spec. identifizierter Bakterientyp konnte durchgängig von allen Stadien der Kohlfliege isoliert werden, die sich an Kohlrüben entwickelten. Er verursacht bei Kohlrüben eine langsame nekrotische Fäulnis und dunkle Verfärbung der befallenen Gewebe. Dieses Bakterium scheint antagonistisch zu anderen Bakterien zu sein, da nur sehr wenige andere Keime mit Stadien der Insekten dieser Population vergesellschaftet gefunden wurden. Umgekehrt fanden sich viele verschiedene Bakterientypen auf Stadien der auf dem Chinakohl lebenden Kohlfliegen. Die Virulenz der pathogenen Kulturen variierte beträchtlich, jedoch verursachten alle irgendeine Art der Weichfäule. Einige dieser aus dem Inneren oberflächlich sterilisierter Puparien isolierten Kulturen wurden als Pseudomonas spec. and Aerobacter spec. bestimmt.Die Art der bakteriellen Kontamination der Kohlfliege scheint hauptsächlich von der Empfänglichkeit ihrer kreuzblütigen Wirtspflanzen gegenüber verschiedenen Typen der Fäulnis nach Verletzung durch die Kohlfliegenmaden abhängig zu sein.Die allgemeinen Zusammenhänge zwischen dem Insekt und den fäulniserregenden Bakterien werden beschrieben.
Approved for publication by the Director of the Wisconsin Agricultural Experiment Station. 相似文献
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Relationship between Protein Synthesis in Tuber Discs and the Protein Synthetic Activity of a Cell-Free Preparation 总被引:2,自引:1,他引:1 下载免费PDF全文
A cell-free system which synthesizes protein was isolated from `aged' discs of Jerusalem artichoke tubers. The synthetic activity was largely associated with the fraction containing mitochondria. Preparations from freshly cut tissue were virtually inactive but increasingly active preparations were obtained from discs `aged' for progressively longer periods; those from 24 hour discs showing maximum activity. The characteristics of this change are reminiscent of the rate of development of invertase, a marker for protein synthesis in the intact disc. Extensive investigations showed that bacterial contamination was not a significant factor in the synthetic activity. 相似文献
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George B. Chapman 《Journal of bacteriology》1960,79(1):132-136
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B A Coller N M Chapman M A Beck M A Pallansch C J Gauntt S M Tracy 《Journal of virology》1990,64(6):2692-2701
Although echovirus 22 (EV22) is classified as an enterovirus in the family Picornaviridae, it is atypical of the enterovirus paradigm, typified by the polioviruses and the coxsackie B viruses. cDNA reverse transcribed from coxsackievirus B3 (CVB3) RNA does not hybridize to genomic RNA of EV22, and conversely, cDNA made to EV22 does not hybridize to CVB3 genomic RNA or to molecular clones of CVB3 or poliovirus type 1. EV22 cDNA does not hybridize to viral RNA of encephalomyocarditis virus or to a molecular clone of Theiler's murine encephalomyelitis virus, members of the cardiovirus genus. The genomic RNA of EV22 cannot be detected by the polymerase chain reaction using generic enteroviral primers. EV22 does not shut off host cell protein synthesis, and the RNA of EV22 is efficiently translated in vitro in rabbit reticulocyte lysates. Murine enterovirus-immune T cells recognize and proliferate against EV22 as an antigen in vitro, demonstrating that EV22 shares an epitope(s) common to enteroviruses but not found among other picornaviruses. 相似文献
69.
Subunit structure of the galactose and N-acetyl-D-galactosamine-inhibitable adherence lectin of Entamoeba histolytica 总被引:19,自引:0,他引:19
W A Petri M D Chapman T Snodgrass B J Mann J Broman J I Ravdin 《The Journal of biological chemistry》1989,264(5):3007-3012
The galactose and N-acetyl-D-galactosamine-inhibitable adherence lectin of Entamoeba histolytica is a cell surface protein which mediates parasite adherence to human colonic mucus, colonic epithelial cells, and other target cells. The amebic lectin was purified in 100-micrograms quantities from detergent-solubilized trophozoites by monoclonal antibody affinity chromatography. The adherence lectin was purified 500-fold as judged by radioimmunoassay. The nonreduced lectin had a molecular mass of 260 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and an isoelectric point of pH 6.2. The amebic lectin reduced with beta-mercaptoethanol consisted of 170- and 35-kDa subunits. Both subunits could be labeled on the cell surface with 125I, and both were metabolically labeled with [3H]glucosamine. The amino termini of the subunits had unique amino acid sequences, and polyclonal antisera to the heavy subunit did not cross-react with the light subunit. The yield of phenylthiohydantoin derivatives from the second and third positions in the sequence of the heavy and light subunits gave a molar ratio of one 170- to one 35-kDa subunit. Antibodies directed to the heavy subunit inhibited amebic adherence to Chinese hamster ovary cells by 100%, suggesting that the heavy subunit is predominantly responsible for mediating amebic adherence. 相似文献
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