RESUMEN
Arabidopsis thaliana mutants impaired in starch biosynthesis due to defects in either ADP glucose pyrophosphorylase (adg1-1), plastidic phosphoglucose mutase (pgm) or a new allele of plastidic phosphoglucose isomerase (pgi1-2) exhibit substantial activity of glucose-6-phosphate (Glc6P) transport in leaves that is mediated by a Glc6P/phosphate translocator (GPT) of the inner plastid envelope membrane. In contrast to the wild type, GPT2, one of two functional GPT genes of A. thaliana, is strongly induced in these mutants during the light period. The proposed function of the GPT in plastids of non-green tissues is the provision of Glc6P for starch biosynthesis and/or the oxidative pentose phosphate pathway. The function of GPT in photosynthetic tissues, however, remains obscure. The adg1-1 and pgi1-2 mutants were crossed with the gpt2-1 mutant defective in GPT2. Whereas adg1-1/gpt2-1 was starch-free, residual starch could be detected in pgi1-2/gpt2-1 and was confined to stomatal guard cells, bundle sheath cells and root tips, which parallels the reported spatial expression profile of AtGPT1. Glucose content in the cytosolic heteroglycan increased substantially in adg1-1 but decreased in pgi1-2, suggesting that the plastidic Glc6P pool contributes to its biosynthesis. The abundance of GPT2 mRNA correlates with increased levels of soluble sugars, in particular of glucose in leaves, suggesting induction by the sugar-sensing pathway. The possible function of GPT2 in starch-free mutants is discussed in the background of carbon requirement in leaves during the light-dark cycle.
Asunto(s)
Arabidopsis/metabolismo , Glucosa-6-Fosfato/metabolismo , Proteínas de Transporte de Membrana/metabolismo , Proteínas de Plantas/metabolismo , Almidón/biosíntesis , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Proteínas de Cloroplastos , Técnicas de Inactivación de Genes , Prueba de Complementación Genética , Glucosa/análisis , Glucosa-1-Fosfato Adenililtransferasa/genética , Glucosa-6-Fosfato Isomerasa/genética , Proteínas de Transporte de Membrana/genética , Mutagénesis Insercional , Mutación , Hojas de la Planta/metabolismo , Proteínas de Plantas/genéticaRESUMEN
In agar diffusion testing of Proteus mirabilis strains sensitive to sulfonamide a synergistic effect of colistine (C) and sulfonamide (S) was demonstrated. By quantitative evaluation these results were confirmed in 100 strains of Proteus mirabilis and 100 strains of indol-positive Proteus spp. using broth dilution method. Combining 1 part C with 10 parts S the mean increase in sulfonamide sensitivity was enhanced fourfold. Increasing the inoculum sensitivity of Proteus against the combination of C and S was still found to range within therapeutic blood levels. Therefore in treatment of Proteus infection the positive synergistic effect of C+S should be taken into consideration.
Asunto(s)
Colistina/farmacología , Proteus/efectos de los fármacos , Sulfonamidas/farmacología , Relación Dosis-Respuesta a Droga , Sinergismo Farmacológico , Pruebas de Sensibilidad Microbiana , Proteus mirabilis/efectos de los fármacos , Proteus vulgaris/efectos de los fármacos , Sulfadiazina/farmacología , Sulfamerazina/farmacología , Sulfatiazoles/farmacologíaRESUMEN
Urine obtained simultaneously by midstream voiding and supra-public bladder aspiration from 500 patients were compared by bacteriological and, in some, microscopic examination. In a second series a similar examination was undertaken on 1000 samples each, obtained by midstream voiding, catheterisation or suprapublic bladder aspiration from different patients. There was no significant difference in sediments or Stansfeld count between midstream and aspirated samples. Qualitative false-positive results for protein were obtained in 20% of midstream samples from women. The Kass count for significant bacteriuria was false-positive in 3.4% of midstream compared with bladder-aspiration samples, in 7.6% for "questionable bacteriuria". Positive counts of under 10(5)/ml were obtained in 41.3%, of under 10(4)/ml in 26.7% of aspirated samples. Counts under 10(4)/ml in midstream-voided samples are usually considered the result of contamination, at times falsely so. "Mixed infections" were 7.8 times more common in catheter and 11.4 to 11.8 times more common in midstream than in aspirated samples. The presence of microorganisms in suprapublic bladder aspiration is always abnormal. Chemotherapy is indicated only on results from bladder aspiration.