No abstract

The dichloromethane extract and pomolic acid ( 5) obtained from leaves of Cecropia pachystachya both reduced carrageenan-induced paw oedema in mice. Interestingly, while the triterpenoid inhibited the in vivo production of interleukin-1beta by 39 %, it had no effect on tumour necrosis factor-alpha production. We also demonstrated that both the dichloromethane extract and 5 inhibited the viability of human polymorphonuclear (PMN) cells in a time- and dose-dependent fashion. The PMN membrane integrity was determined with the aid of flow cytometry by means of the exclusion of propidium iodide as assay. Although the cell membrane integrity was altered, neither the extract nor 5 produced cellular necrosis. Moreover, the development of hypodiploid nuclei and DNA fragmentation in the PMN cells were both dependent on dose and time. Finally, in the annexin V-FITC binding assay, compound 5 increased the total of apoptotic cells by 42 % at 100 microM and by 71 % at 200 microM with respect to the control group. In conclusion, both the dichloromethane extract of ambay and isolated compound 5 inhibit the viability of PMN cells through apoptosis. Since they can regulate human neutrophil functions in this way, it is likely that these substances can also limit inflammation.

In this paper, we examine the importance of glutathione in symbiosis, using a glutathione biosynthetic gshB mutant derived from Rhizobium tropici CIAT899, a common bean (Phaseolus vulgaris) endosymbiont. Plants infected with the mutant strain presented a delayed nodulation phenotype and a reduction in the dry weight of aerial part of plants, suggesting diminished nitrogen-fixation activity. In addition, bacterial gshB expression was assayed in wild-type infected nodules, during the different steps of nodulation, and found to increase in mature and early senescent nodules. Conspicuously, nodules induced by gshB mutant bacteria presented an early senescent pattern, which was associated with increased levels of superoxide accumulation. These results provide a direct evidence of the role of bacterial glutathione in protecting nodules from reactive oxygen species, which may determine nodule senescence.

No abstract

No abstract

No abstract

histoquímica de los órganos subterráneos de plantas trepadoras medicinales rioplatenses (Argentina)". Lilloa 54 (2). El objetivo de este estudio fue caracterizar los rizomas y raíces por sus atributos histológico-estructurales y determinar la presencia de compuestos químicos que faciliten la identificación de los taxones de muestras enteras o fragmentadas de los mismos. Se analizó material fresco recolectado en el área de estudio y ejemplares de herbario (LPAG). Para las preparaciones anatómicas se procedió con técnicas usuales para microscopía óptica. Se realizaron reacciones histoquímicas para identificar almidón, mucílagos, lípidos y taninos. Los principales rasgos micrográficos resultaron: las características de las células y número de estratos celulares de la rizodermis y exodermis; el desarrollo de la peridermis; las peculiaridades del parénquima cortical y de la estela; el engrosamiento de las paredes celulares de las células corticales adyacentes a la endodermis y de la endodermis; la presencia de reservorios secretores y tipos de cristales. Sobre la base de los datos obtenidos se generaron tablas comparativas con los grupos químicos identificados y construyeron claves dicotómicas de las especies que constituyen una herramienta de valor en el control de calidad botánica.

This is comparative study of Ilex paraguariensis St. Hil. var. paraguariensis Loes., and cogeneric Argentine adulterants: I. dumosa Reissek var. dumosa Reissek, I. dumosa var. guaranina Loes., I. brevicuspis Reissek, I. theezans Reissek and I. argentina Lillo. The anatomy and quantitative micrographic parameters (proportional magnitudes, stomata index and palisade ratio) of these leaves was studied to the establish standards in agreement with the WHO for the vegetables drugs. A micrographic parameters table is presented for control quality of the raw material, fragmentary or powdered.