Antonio Carlos Ferreira da Silva

Efeito anti-proliferativo das infusões de Achyrocline satureioides DC (Asteraceae) sobre o ciclo celular de Allium cepa

Achyrocline saturoides (marcela) is used in Brazilian folk medicine as a tea in the treatment of digestive and inflammatory diseases. The anti-proliferative effect of infusions of marcela on onion cell cycle was evaluated by using the inflorescences of recently collected marcela and after the storage for 30 months. Marcela inflorescences were collected for the infusion preparations in 2003 and in 2005 (used still fresh). We prepared the infusions at two concentrations 5.0 mg/mL (concentration used as tea) and 20 mg/mL. We used two groups of six onion bulbs for each population of marcela, and one group of bulbs of each population was withdrawn as a control group. All bulbs rooted in distilled water and after they were transferred to the extracts of marcela and they were kept there for 24 hours (control bulbs remained under water). The root tips were collected, after fixed in ethanol acetic acid (3:1) for 24 hours and, stored under alcohol 70%. A total of 6000 cells per group of bulbs was analyzed, and the mitotic indexes were calculated and undergone to statistical analysis by using c2 at 5%. The conclusions were that the infusions of marcela have anti-proliferative action on the cell cycle of onion and that this inhibitory action on the cell division increases according to the increase of the infusion concentration, after storage as well.

Uso do sistema teste de Allium cepa como bioindicador de genotoxicidade de infusões de plantas medicinais

All over the world, many species of medicinal plants are used for disease treatments. However, most of them were not deeply studied; and the presence of cytotoxic or mutagenic substances in their composition or resulting from their metabolism may be harmful to human beings. The mutagenic effects caused by such substances result in chromosomal changes which are detecTable during the cell cycle of a species through cytogenetic analysis. The Allium cepa test system is widely used for evaluating the genotoxic potential of infusions (tea) made of medicinal plants, through the cell cycle analysis. The knowledge of the genotoxic potential of such species through the Allium cepa test serves as a warning and safety bioindicator for the population who uses medicinal tea quite often as the unique alternative for disease treatment of its people. In the review article, we intend to inform people about the importance of the Allium cepa test for evaluating the genotoxicity of infusions of medicinal plants.

Effects of Pterocaulon polystachyum DC. (Asteraceae) on onion (Allium cepa) root-tip cells

In Brazil leaf infusions of the plant Pterocaulon polystachyum DC (Asteraceae) are used to treat digestive problems. We used plants from six P. polystachyum populations to prepare fresh aqueous leaf infusions at the concentration normally used in Brazil (2.5 g L-1) and at twice (5 g L-1) and four times (10 g L-1) this concentration. We rooted onion bulbs in a water control or one of the infusions for 24 h and used the in vivo onion (Allium cepa) root-tip cell test to investigate the potential mutagenicity of the infusions by calculating the mitotic index for the control and the experimental treatments and comparing them using the Chi-squared test (c2, p = 0.05). There was a highly significant decrease in the mitotic index of root-tip cells treated with infusion as compared to those exposed to water only. These results indicate that P. polystachyum infusions present cytotoxic and anti-proliferative activity and therefore have therapeutic potential.

Extracts affecting mitotic division in root-tip meristematic cells

Some species of Psychotria (Rubiaceae) are important in herbal medicine, where their extracts are used internally for infections of the female reproductive system, bronchitis, gastrointestinal disturbances, skin irritations, tumors, ulcers, and eye disturbances. The antiproliferative and genotoxic effects of Psychotria myriantha Mull. Arg. and P. leiocarpa Cham. et Schlecht infusions on the Allium cepa L. cell cycle were evaluated. The teas were prepared by infusing the leaves in distilled water, in two concentrations: 1.13 mg/mL and 6.78 mg/mL. Three groups of four bulbs were used for each Psychotria species. After the bulbs rooted in distilled water, they were transferred to the teas for 24 hours, except for the control that stayed in water. The rootlets were then collected, fixed in ethanol-acetic acid (3:1) for 24 hours, and stored in 70% ethanol. For each group of bulbs, 4000 cells were analyzed, calculating the mitotic indexes, submitting them to statistic analysis, using the χ2 test (p = 0.05). The results showed a decrease in mitotic index with an increase in tea concentration in both species. In P. leiocarpa, the mitotic index values differed significantly between the control and concentration of 6.78 mg/mL (χ2 = 9.863). For P. myriantha, the values referring to the mitotic index differed greatly between the control and the treatments (χ2 = 124.8). With this study, it was determined that P. myriantha and P. leiocarpa infusions possess antiproliferative effects on the A. cepa cell cycle, and teas of P. myriantha also have genotoxic activity.

Promoção de enraizamento de microestacas de um clone de Eucalyptus sp. por Trichoderma spp.

The purpose of this research was to apply antagonistic isolates of fungi to induce microcutting rooting of an Eucalyptus sp. clone. One non-pathogenic isolate of Cylindrocladium spp. and three antagonistic isolates of Trichoderma spp (E15, S2 and St) were used for the microcutting rooting experiment. The latter gave better results in the antagonistic in vitro test using the method of direct confrontation against the pathogenic isolate of Cylindrocladium spp, being inoculated in the microcutting rooting substrate, in greenhouse conditions. Increase of microcutting survival was observed in the presence of isolates of Trichoderma spp. and Cylindrocladium spp. when compared with control in an environment naturally infested with Botrytis cinerea. The treatments with the isolates ST, E15 and S2 of Trichoderma spp. and Cyl of Cylindrocladium spp. increased the survival of Eucalyptus sp. microcuttings. The E15 isolate promoted a significant increase in the rooting percentage (62.25%) compared to the control treatment (28.77% ).

Cytotoxic effects of infusions (tea) of Solidago microglossa DC. (Asteraceae) on the cell cycle of Allium cepa

The medicinal specie Solidago microglossa DC., which is native from South America, is used as infusion (tea) for stomach disorders in popular medicine. This study aimed to evaluate the potential cytotoxic effect of these infusions on the cell cycle of Allium cepa. In natura leaves of three populations of this species were used in preparing infusions at two concentrations: 1.75 mg/mL and 14 mg/mL. Onion (Allium cepa) root-tip cells were used as test system in in vivo assays. Slides were done through smashing technique. Cells were analyzed in all cell cycles of A. cepa, totalizing 6000 cells for each group of bulbs. The mitotic index (MI) was calculated, and the statistical analysis was carried out through the Chi-square test (χ2 = 0.05). The results show that the infusions of S. microglossa at a highest concentration (14 mg/mL) caused a significant reduction in the MI compared with control in the studied populations. In concentrations commonly used by people there was a significant increase of MI in relation to controlled populations 1 and 3 and a decrease in population 2. In conclusion, infusions of S. microglossa presented antiproliferative effect at a highest concentration.

Fungos antagonistas a Sclerotinia sclerotiorum em pepineiro cultivado em estufa

White mold caused by Sclerotinia sclerotiorum may severely damage vegetables grown in greenhouses. To develop a biological control program for this pathogen proper antagonists are needed. This work aimed to select efficient fungi antagonists for controlling S. sclerotiorum on cucumber (Cucumis sativus) grown in greenhouses, and to evaluate the effect of the antagonist on the growth of the vegetable. An isolate of S. sclerotiorum obtained from cucumber and 112 fungi isolates belonging to four genera were used: Trichoderma, Fusarium, Penicillium, and Aspergillus. For the in vitro experiment, the cellophane method was used and eight Trichoderma virens isolates were selected that had inhibited the pathogen growth by 94 to 100%. Greenhouse experiments used sterilized and non-sterilized substrate in plastic cups and non-sterilized substrate in plastic bags. The substrate was inoculated with S. sclerotiorum and the eight isolates of T. virens were used as antagonists. All eight isolates controlled damping-off of plants caused by S. sclerotiorum, but the effect on cucumber growth varied according to the isolate and the substrate treatment.

Número de cromossomos em populações de Achyrocline satureioides Lam. (marcela) do Estado do Rio Grande do Sul, Brasil

The cytogenetics of medicinal plants in a country enlarges the perspectives of conservation of the vegetal diversity of species generally used in popular medicine. Some of the species used medicinally in Brazil are native, and Achyrocline satureioides Lam. (marcela), from Asteraceae Family, is highlighted among them. In this study the first counting of the chromosomal number in marcela populations, which are native from Rio Grande do Sul State, was performed. Seeds of five populations of marcela were collected in their native local. Such seeds were put at room temperature to germinate. After germinating, the root-tips were collected and pre-treated with saturated solution of paradichlorobenzene for five hours, fixed in absolute ethanol glacial acetic acid (3:1) for 24 hours at room temperature and, after that, maintained in alcohol 70% until they were used. The analysis of the chromosomal number was performed with slides of root-tips by using the squashing technique, hydrolysis in HCI 5N for 10min, acetic acid application 45% for 1min, squashing of the root-tips and staining in orcein acetic 2%. All populations presented 2n=24 chromosomes, suggesting it as the probable diploid number of the species.

Sensibilidade de isolados de Trichoderma spp. a benomil e iprodione

The objective of this work was to evaluate the sensibility of wild isolates of Trichoderma spp.; T. viride (Tal1); T. viride (T2b); T. harzianum (Tal8); T. viride (Tligjap); T. harzianum (TW5) e T. harzianum (TMA4); at concentrations of 0; 0.25; 0.5; 1.0; and 2.5µg/ml of active ingredient of benomyl and at concentrations of 0; 2.5; 5.0; 10.0 e 100.0µg/ml of iprodione, in vitro. Fungitoxicity was evaluated by measuring sporulation, in Neubauer chamber, after seven days of incubation and calculation of colony growth rate. In general, benomyl and iprodione impaired micelial growth and sporulation. The isolate TW5 showed to be less affected by the fungicides. The mycelial growth was reduced at benomyl and at iprodione, and it also produced more spores in the presence of fungicides than the others isolates.

Degenerescência de batata-semente básica após um ou dois períodos de cultivo

The infection by Potato leafroll virus (PLRV) and by Potato virus Y (PVY) is the main cause of potato degeneration in Brazil. During two planting periods, September to December of 1999 and March to June of 2000, the % of infection of basic potato seeds by PLRV and PVY was determined, on potato producer regions of Rio Grande do Sul and Santa Catarina States. In the first period, 623 samples from nine regions were serologically tested (DAS-ELISA), revealing 17 and 3% of PVY and PLRV infections, respectively. The percentage of infection of cultivar Baronesa was 7,5 and 0,3%, Catucha 22 and 19%, Elvira 42 and 0%, and Monalisa 16 and 4%. In the second period part of the tubers harvested on the first one were planted, and 301 samples from two regions were tested, revealing a percentage of infection of 58% for PVY and 11% for PLRV. The percentage of infection of cultivar Baronesa was 67 and 6%, Catucha 68 and 49%, Elvira 94 and 2%, and Monalisa 35 and 0%.