Asymbiotic seed germination and in vitro seedling development of the threatened orchid Hoffmannseggella cinnabarina

Hoffmannseggella cinnabarina has not been found in the wild for the last 70?yr in the State of S?o Paulo and, therefore, wild populations of this native orchid are thought to be extinct. This investigation studied seed storage at a low temperature, in vitro germination, and seedling development of H. cinnabarina in order to establish an optimized protocol for propagation, and thus assure species conservation. Seeds of different ages were incubated on Knudson C (KC), Murashige and Skoog, and Vacin and Went media with or without 1???M of N⁶-benzyladenine (BA) and exposed to either 12 or 16?h of light (30???mol?m^?2?s^?1 at 26?±?2°C). Seed surface sterilization was deleterious to 3-mo-old seeds and severely reduced the viability of the 4-mo-old seeds. More mature seeds were not affected by the sterilization procedure. In general, the germination of 4-, 5-, 6-, and 7-mo-old seeds increased when BA was added to the culture medium especially under 16?h of light. Germination rates were highest with 8- and 9-mo-old seeds, and application of BA failed to enhance germination rates further. Developmental studies revealed that this cytokinin reduced seed and protocorm mortality rates; however, protocorm development was negatively affected in its presence. Seedling development was more pronounced when KC medium with 16?h of light was used. Long-term seed storage at 4°C did not provide promising results. The protocol described in this study proved to be efficient and relevant to in vitro seed germination and initial development of H. cinnabarina, and thus will contribute to conservation of this orchid species.     

Blood glucose control for individuals with type-2 diabetes: acute effects of resistance exercise of lower cardiovascular-metabolic stress

ABSTRACT: Moreira, SR, Sim?es, GC, Moraes, JFVN, Motta, DF, Campbell, CSG, and Sim?es, HG. Blood glucose control for individuals with type-2 diabetes: Acute effects of resistance exercise of lower cardiovascular-metabolic stress. J Strength Cond Res 26(10): 2806-2811, 2012-This study compared the effects of resistance exercise (RE) intensities on blood glucose (GLUC) of individuals without (ND) and with type-2 diabetes (T2D). Nine individuals with T2D and 10 ND performed: (a) RE circuit at 23% of 1 maximal repetition (1RM) (RE_L); (b) RE circuit at 43% 1RM (RE_M); and (c) control (CON) session. Blood lactate (LAC) and GLUC were measured before, during, and postinterventions. Double product (DP) and rate of perceived exertion (RPE) were recorded. The area under the curve (AUC) revealed the effects of RE circuits in reducing GLUC in individuals with T2D (RE_L: 12,556 ± 3,269 vs. RE_M: 13,433 ± 3,054 vs. CON: 14,576 ± 3,922 mg.dl.145 minutes; p < 0.05) with a lower AUC of GLUC in RE_L in comparison to RE_M. Similarly, for ND the RE_L reduced the AUC of GLUC when compared with RE_M and CON (RE_L: 10,943 ± 956 vs. RE_M: 12,156 ± 1,062 vs. CON: 11,498 ± 882 mg.dl.145 minutes; p < 0.05). The AUC of GLUC was higher for T2D compared with ND on CON condition (p = 0.02). However, after RE circuits the difference between groups for AUC of GLUC was abolished. The RE_M for T2D was more stressful when compared with RE_L for LAC (CON: 1.3 ± 0.5 vs. RE_L: 5.5 ± 1.5 vs. RE_M: 6.8 ± 1.3 mmol·L; p < 0.05), DP (CON: 8,415 ± 1,223 vs. RE_L: 15,980 ± 2,007 vs. RE_M: 18,047 ± 3,693 mmHg.bpm; p < 0.05), and RPE (RE_L: 11 ± 2 vs. RE_M: 13 ± 2 Borg Scale; p < 0.05). We concluded that RE_L and RE_M were effective in reducing GLUC for individuals with T2D, with lower cardiovascular-metabolic and perceptual stress being observed for RE_L. These data suggest that acute RE sessions at light or moderate intensities are effective for controlling GLUC in individuals with T2D.     

Evaluation of Chalcone Derivatives as Photosynthesis and Plant Growth Inhibitors

We report the evaluation of chalcone derivatives as photosystem II (PSII) and plant growth inhibitors. Chalcone derivatives were evaluated as PSII inhibitors through Chl a fluorescence measurement. (E)-Chalcone ( 6a ) and (E)-3-(4-bromophenyl)-1-(4-fluorophenyl)prop-2-en-1-one ( 6j ) showed the best results, reducing the performance index on absorption basis parameter (PI_abs) by 70 %. Additionally, the decrease of TR₀/RC and ET₀/RC parameters indicates that the chalcone derivatives limited the number of active PSII reaction centers and the amount of trapped energy within them. Compounds 6a and 6j both act as post-emergent herbicides at 50 μM, reducing the root biomass of the Ipomoea grandifolia weed by 72 % and 83 %, respectively, corroborating the fluorescence results. The selectivity against weeds as compared to valuable crops by compounds 6a and 6j were evaluated employing Zea mays and Phaseolus vulgaris plants. In these, our newly synthesized compounds showed no effects on biomass accumulation of roots and aerial parts when compared to the control, providing valuable evidence for the role of these compounds as selective inhibitors of the growth of undesired weeds.     

Trypanosoma cruzi: phagolysosomal fusion after invasion into non professional phagocytic cells

Parasite-containing endocytic vacuoles are formed during the process of in vitro interiorization of the trypomastigote forms of Trypanosoma cruzi by primary culture of mouse fibroblasts, heart and skeletal muscle cells. Fusion of these vacuoles with host cell lysosomes takes place. The process of T. cruzi-muscle cell interaction was analysed by ultrastructural cytochemistry. Two lysosomal enzymes, acid phosphatase and aryl sulphatase and the fusion of peroxidase-labeled secondary lysosomes with the parasitophorus vacuoles were studied. These finding indicate that the basic mechanism of interaction of T. cruzi with the so called non phagocytic cells is similar to that which occurs with phagocytic cells.     

Alterations of the resin canal system of <Emphasis Type="Italic">Pinus pinaster</Emphasis> seedlings after fertilization of a healthy and of a <Emphasis Type="Italic">Hylobius abietis</Emphasis> attacked stand

Changes in resource availability and biotic and abiotic stress may alter the defensive mechanisms of pine trees. The effect of fertilisation on the resin canal structure of Pinus pinaster seedlings established in two trials in NW Spain, one attacked by Hylobius abietis and the other non-attacked, was studied. The leaders of 50 plants were destructively sampled and the resin canal density, the canal area and its relative conductive area in the phloem and xylem were assessed. Experimentally increased nutrient availability significantly decreased resin canal density in the phloem of the seedlings in the two analysed trials, where unfertilised seedlings presented up to 30% more resin canal density than the fertilised seedlings (mean value ± SEM = 0.32 ± 0.02 resin canals mm⁻² in the fertilised plants versus 0.45 ± 0.04 resin canals mm⁻² in the control plants). Fertilisation had no effect on the resin canal system in the xylem, but significantly increased tracheid size. Significant differences of resin canals among sites were observed mainly in the xylem; the resin canal density was 1.7-fold greater in the attacked site than in the non-attacked site. The similar structure of phloem resin canals in both sites supports that phloem resin canals are constitutive mechanisms of defence in P. pinaster, whereas xylem resin canals would be constitutive mechanisms but also inducible mechanisms of resistance following the attack of pine weevils or bark beetles. XM and LS equally contributed to this paper.