Fitodefensivos em plantas medicinais: macromoléculas hidrofílicas de folhas de mil folhas (Achillea millefolium L. ) inibem o crescimento in vitro de bactérias fitopatogênicas / Agrochemicals in medicinal plants: hydrophilic macromolecules from leaves of "mil folhas" (Achillea millefolium L. ) inhibit in vitro growth of phytopathogenic bacteria

Extratos aquosos da planta medicinal Achillea millefolium contêm macromoléculas de interesse para desenvolver fitodefensivos para a agricultura. Duas frações de mil folhas foram obtidas por ultrafiltração, E1 (contendo moléculas maiores que 30 kDa), e E3 (peptídeos entre 1 e 10 kDa) que inibiram o crescimento das bactérias fitopatogênicas Ralstonia solanacearum, gram-negativa, e Clavibacter michiganensis subsp. michiganensis, gram-positiva, com dependência de concentração. Os valores de concentração inibitória mínima (CIM) para ambos os extratos e bactérias foram baixos, entre 20 e 80µM. A CIM relativa à proteína total evidenciou a presença de macromoléculas muito ativas em E3, embora com baixa concentração proteica. E3 se aplica à prospecção de peptídeos antimicrobianos. Estimar a CIM relativa à quantidade de amostra vegetal valorizou o potencial antimicrobiano natural de E1, que contém alta concentração proteica. E1e E3 se aplicam ao desenvolvimento de fitodefensivos para uso biotecnológico. A ultrafiltração fracionou as amostras de forma nativa, rápida, e com baixo custo; além de dessalinizar, clarificar, purificar, e concentrar E1 e E3. Esse estudo inédito sobre a separômica e a ação antimicrobiana de extratos macromoleculares aquosos de mil folhas sugere que plantas cicatrizantes podem apresentar grande potencial para desenvolver fitodefensivos agrícolas naturais não danosos, à semelhança de medicamentos fitoterápicos.

Aqueous extracts from the medicinal plant Achillea millefolium contain macromolecules of interest to develop agrochemicals for agriculture. Two fractions of "mil folhas" were obtained by ultrafiltration, E1 (containing molecules larger than 30 kDa) and E3 (peptides between 1 and 10 kDa), which inhibited the growth of phytopathogenic bacteria Ralstonia solanacearum, gram-negative, and Clavibacter michiganensis subsp. michiganensis, gram-positive, concentration-dependent. The values of minimum inhibitory concentration (MIC) for both extracts and both bacteria were low, ranging from 20 to 80µM. The MIC relative to total protein evidenced the presence of very active macromolecules in E3, although showing low protein concentration. E3 applies to the prospection of antimicrobial peptides. The estimated MIC relative to the amount of plant sample valued the natural antimicrobial potential of E1, which contains high protein concentration. E1 and E3 can be used in the development of agrochemicals for biotechnological purposes. The ultrafiltration procedure fractionated the samples in a rapid and native way and at a low cost; it also desalted, clarified, concentrated and purified both E1 and E3. This pioneering study on the separomics and on the antimicrobial activity of macromolecular aqueous extracts from "mil folhas" suggests that healing plants have great potential to develop non-harmful agricultural natural agrochemicals, similarly to the available phytotherapic drugs.

Enkephalin- and serotonin-like immunoreactivity in the aortico-pulmonary paraganglia of the white-belly opossum Didelphis albiventris (Marsupialia).

Serial histological sections of the interatrial septum and basal heart vessels of the weaned and juvenile white-belly opossum (Didelphis albiventris) were obtained in order to study the presence of paraganglia and their content of regulatory peptides and serotonin. Paraganglion groups were mapped between the aorta and pulmonary arteries and close to the bifurcation of the pulmonary trunk and were found to contain cells with immunoreactivity to serotonin and to the neuroendocrine markers PGP 9.5 and NSE. When these paraganglia were tested for immunoreactivity to a battery of regulatory peptides, all were found to be positive for methionine-enkephalin, leucine-enkephalin and galanin. The hypothesis is raised that these peptides and serotonin, besides catecholamines, produced by these paraganglia may play a physiological role in the functions of the cardiovascular system of the white-belly opossum.

Immunocytochemical identification of neuroendocrine markers in human cardiac paraganglion-like structures.

Paraganglion-like structures (PLS) containing chromaffin-positive cells have been reported to be present in the adult human heart. The present work was initiated in order to evaluate the density of these structures in the interatrial septum and to study the presence of immunoreactivity of their cells to NSE and PGP 9,5 antibodies, two neuroendocrine markers. Six hundred 6-microns paraffin serial sections were obtained from the upper third of the interatrial septum from six adult human hearts. From 2 to 12 paraganglia were found in each case, and their principal cells stained positively with NSE and PGP 9,5 antibodies. Depending on how these PLS related to other cardiac structures, four different types were identified: Type I - "True paraganglia" (located adjacent to ganglia or nerve fibers); Type II - "Free paraganglia" (immersed in the interatrial adipose tissue, without evident connection to other structures); Type III - "Intraganglionic paraganglia" (located within the nervous ganglia); Type IV - "Intramyocardic paraganglia" (small nests of immunoreactive cells closely related to myocardiocyte bundles). These cardiac paraganglia, which probably belong to the visceral-autonomic group, may have a role in the regulation of the cardiac function and in the adaptive mechanisms of the heart. Its is also possible that they originate functioning and non-functioning tumours.

Mechanism of the pulmonary edema induced by intravenous injection of scorpion toxin in the rat.

The intravenous injection of purified scorpion toxin (tityustoxin, TsTX) into unanesthetized rats induces a severe systemic hypertension followed by a hemorrhagic edema of the lungs. The edema is focal or diffuse, whereas the hemorrhage is always focal and less prominent than the edema. Anesthesia of the rats prevents the appearance of pulmonary edema. It seems likely that this protective action of the anesthesia is due, at least in part, to an interference with the hypertension induced by TsTX. The pulmonary edema is prevented by bilateral adrenalectomy, guanethidine or phenoxybenzamine. It is suggested that the edema depends on a sympathetic-adrenal discharge and that catecholamines released by TsTX act on alpha adrenergic receptors. The mean kininogen content of the rat plasma, 1 h after TsTX injection, is not significantly different from that found in the control animals. The possible role played by kinins and other mediators in the early phases of the pulmonary edema induced by TsTX is under investigation.

Studies on the vesicular component of the Auerbach's plexus and the substance P content of the mouse colon in the acute phase of the experimental Trypanosoma cruzi infection.

A dramatic reduction in the total number of dense vesicles in Auerbach's plexus of the mouse colon was observed during the acute phase of experimental American Trypanosomiasis (Chagas' disease). A significant decrease in substance P activity of the colon of inoculated animals was also measured. It is suggested that this decrease in substance P activity could be related to the reduction in the number of dense vesicles in Auerbach's plexus.