Matrix dominance and landscape resistance affect genetic variability and differentiation of an Atlantic Forest pioneer tree

Landscape Ecology - Despite the importance of secondary forests for the maintenance of biodiversity, the impact of pioneer trees on habitat loss and fragmentation is poorly understood. We analyzed...     

Macronutrient deficiency and anatomic modifications in crambe leaves

Abstract

This study had the objective of assessing growth, deficiency symptoms and leaf anatomy of crambe plants submitted to macronutrient availability. The experimental design was the complete randomized with four replications. The first treatment consisted of cultivating crambe plants in a nutrient solution completed with N, P, K, Ca, Mg, and S. Using the diagnosis by subtraction, the other treatments consisted of the same solution with individual omission of each nutrient, totaling seven treatments. Supplement of different solutions took place two weeks after emergence. One week forward, visual symptoms of deficiency started to be evaluated. By the end of the experiment, the number of leaves, number of branches, shoot dry matter and leaf anatomic parameters were evaluated. Nutrient deficiency limited shoot dry matter in the following order: N?>?Ca?>?P>Mg?>?S?>?K. Subtracting Ca from the solution was most limiting to crambe growth once plants did not even reach reproductive stages. Individual subtractions of each macronutrient anatomically altered crambe leaves, especially omitting Ca, K, and S, which reduced tissue thickness.     

Hierridin B Isolated from a Marine Cyanobacterium Alters VDAC1, Mitochondrial Activity,and Cell Cycle Genes on HT-29 Colon Adenocarcinoma Cells

Background: Hierridin B was isolated from a marine cyanobacterium Cyanobium sp. strain and induced cytotoxicity selectively in HT-29 adenocarcinoma cells. The underlying molecular mechanism was not yet elucidated. Methods: HT-29 cells were exposed to the IC₅₀ concentration of hierridin B (100.2 μM) for 48 h. Non-targeted proteomics was performed using 2D gel electrophoresis and MALDI-TOF/TOF mass spectrometry. The mRNA expression of apoptotic and cell cycle genes were analyzed by real-time PCR. Automated quantification of 160 cytoplasm and mitochondrial parameter was done by fluorescence microscopy using CellProfiler software. Results: Proteomics identified 21 significant different proteins, which belonged to protein folding/synthesis and cell structure amongst others. Increase of VDAC1 protein responsible for formation of mitochondrial channels was confirmed by mRNA expression. A 10-fold decrease of cytoskeleton proteins (STMN1, TBCA) provided a link to alterations of the cell cycle. CCNB1 and CCNE mRNA were decreased two-fold, and P21CIP increased 10-fold, indicative of cell cycle arrest. Morphological analysis of mitochondrial parameter confirmed a reduced mitochondrial activity. Conclusion: Hierridin B is a potential anticancer compound that targets mitochondrial activity and function.     

Reactivity of human salivary proteins families toward food polyphenols

Tannins are well-known food polyphenols that interact with proteins, namely, salivary proteins. This interaction is an important factor in relation to their bioavailability and is considered the basis of several important properties of tannins, namely, the development of astringency. It has been generally accepted that astringency is due to the tannin-induced complexation and/or precipitation of salivary proline-rich proteins (PRPs) in the oral cavity. However, this complexation is thought to provide protection against dietary tannins. Neverthless, there is no concrete evidence and agreement about which PRP families (acidic, basic, and glycosylated) are responsible for the interaction with condensed tannins. In the present work, human saliva was isolated, and the proteins existing in saliva were characterized by chromatographic and proteomic approaches (HPLC-DAD, ESI-MS, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and MALDI-TOF). These approaches were also adapted to study the affinity of the different families of salivary proteins to condensed tannins by the interaction of saliva with grape seed procyanidins. The results obtained when all the main families of salivary proteins are present in a competitive assay, like in the oral cavity, demonstrate that condensed tannins interact first with acidic PRPs and statherin and thereafter with histatins, glycosylated PRPs, and bPRPs.     

Dry matter production and nutrient accumulation in Crotalaria spectabilis shoots

Among Crotalaria L. species, Crotalaria spectabilis stands out for its good adaptation to various production systems in the Brazilian cerrado, high nutrient cycling, reduction of weeds incidence, and antagonistic action on the nematode population. Thus, the aim of this study was to characterize dry matter production and macronutrient accumulation in plant shoots at different growth and development stages. The experimental design consisted of random blocks, with 12 cutting times and 5 repetitions. At each collection, the plants were divided into leaves, stems?+?branches, pods, and seeds, for macronutrient level determination. The stem?+?branches are the primary drain on nutrients during the formation of reproductive structures. Macronutrient concentration in the shoots exhibited the following order: K?>?N>Ca?>?P>Mg?>?S and the order of nutrient export in seeds was N?>?K>P?>?Ca?>?S>Mg. Cutting aimed at nutrient supply to the soil should be conducted before pod formation, and at the end of the cycle for biomass production.     

Coffee‐leaf extract and phosphites on the curative control of powdery mildew in eucalyptus mini‐stumps

The aim of this study was to evaluate the effectiveness of a plant extract obtained from the leaves of coffee plants infected by Hemileia vastatrix (NEFID), different formulations of phosphites and the combination of the extract and phosphites in controlling powdery mildew in eucalyptus mini‐stumps, as well as to study the effects on the production of mini‐cuttings and their rooting percentage. The experiments were conducted on two eucalyptus hybrids (‘urocam’ and ‘urograndis’) in a clonal garden and greenhouse. First, the NEFID plant extract and phosphites of copper, zinc, potassium and potassium/manganese were evaluated to determine their effectiveness in controlling powdery mildew and their toxic effect on the fungus' morphology. Subsequently, we analysed the direct fungitoxicity, curative efficiency and anti‐sporulating action of the NEFID extract and various combinations of phosphites with or without the extract, and we also evaluated their effects on shoot production and rooting in eucalyptus mini‐cuttings. The NEFID plant extract and phosphites of Cu, Zn and K/Mn were more effective than the fungicide pyraclostrobin + epoxiconazole in the control of powdery mildew. Potassium phosphite was not effective in controlling the pathogen. Among the tested mixtures, the combination of 50% NEFID plant extract and 50% copper phosphite was the most effective because it exhibited direct toxicity on powdery mildew, a high curative efficiency, anti‐sporulating action and no adverse effects on the production of shoots or rooting in eucalyptus mini‐cuttings.