USE OF ISOTOPIC TECHNIQUES TO EVALUATE FOLIAR FERTILIZATION EFFICIENCY

In this study, the foliar fertilization efficiency was assesed by using nuclear techniques and the stable isotope  15N. The objective was to increase nitrogen use efficiency in plants. In addition, the mobility of nitrogen in plants was evaluated. The environmentlly friendly impact of this type of fertilizer is supported by means of an increase in nutrients uptake from the natural soil supplies, and as a result of foliar fertilization. The trials were conducted in INCDPAPM-ICPA Bucharest greenhouse, using sunflower as test plant. To evaluate the mobility of nitrogen in plants, a PK with mezo and microelements (Mg, S, Fe, Cu, Zn, Mn, Co, Mo) foliar fertilizer was enriched with labeled 15N  and unlabeled N, using  urea and ammonium nitrate as nitrogen sources.  Therefore, 6% of the total nitrogen content was represented by the 15N labeled isotope (in all three forms: ammoniacal,15N-NH4, nitric , 15N-NO3 and amide, 15N-NH2). The obtained results suggest that nuclear techniques can be successfully used in agrochemical research to deepen plant nutrition and nutrients translocation studies

DEVELOPMENT OF A NOVEL FOLIAR FERTILIZER WITH ZINC

Zinc deficiency, resulted from various stress factors, limits agricultural production worldwide. Therefore, research into developing sustainable methods to alleviate this type of deficiency should be a priority. This study presents the development of a new foliar fertlizer, focusing on its formulation, characterization, and testing. The fertilizer formula associates a classic NPK and micronutrients (Cu, Zn, Fe, Mn) matrix with organic substances having bio-stimulating effect: humic acids and algae extracts. The composition of the experimental fertilizer (8.2% N, 3.9% P, 3.6% K, 0.8% Zn) is formulated to prevent and correct imbalances in plant mineral nutrition, especially those caused by zinc deficiency. A set of field trials were conducted in order to assess the effect of the fertilizer on grapevine (cv Chasslas dore) and maize (DKC 4590). Experimental data indicated that application of the foliar fertilizer had signifficant contribution to the improvment of yield, leaf nutrient and chlorophyll content, and crop quality parameters

MALDI imaging mass spectrometry for direct tissue analysis: a new frontier for molecular histology

Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) is a powerful tool for investigating the distribution of proteins and small molecules within biological systems through the in situ analysis of tissue sections. MALDI-IMS can determine the distribution of hundreds of unknown compounds in a single measurement and enables the acquisition of cellular expression profiles while maintaining the cellular and molecular integrity. In recent years, a great many advances in the practice of imaging mass spectrometry have taken place, making the technique more sensitive, robust, and ultimately useful. In this review, we focus on the current state of the art of MALDI-IMS, describe basic technological developments for MALDI-IMS of animal and human tissues, and discuss some recent applications in basic research and in clinical settings

Cholesterol Pathways Affected by Small Molecules That Decrease Sterol Levels in Niemann-Pick Type C Mutant Cells

Niemann-Pick type C (NPC) disease is a genetically inherited multi-lipid storage disorder with impaired efflux of cholesterol from lysosomal storage organelles.The effect of screen-selected cholesterol lowering compounds on the major sterol pathways was studied in CT60 mutant CHO cells lacking NPC1 protein. Each of the selected chemicals decreases cholesterol in the lysosomal storage organelles of NPC1 mutant cells through one or more of the following mechanisms: increased cholesterol efflux from the cell, decreased uptake of low-density lipoproteins, and/or increased levels of cholesteryl esters. Several chemicals promote efflux of cholesterol to extracellular acceptors in both non-NPC and NPC1 mutant cells. The uptake of low-density lipoprotein-derived cholesterol is inhibited by some of the studied compounds.Results herein provide the information for prioritized further studies in identifying molecular targets of the chemicals. This approach proved successful in the identification of seven chemicals as novel inhibitors of lysosomal acid lipase (Rosenbaum et al, Biochim. Biophys. Acta. 2009, 1791:1155-1165)

Interactions of Ca(2+) with sphingomyelin and dihydrosphingomyelin.

The changes induced by Ca(2+) on human lens sphingolipids, sphingomyelin (SM), and dihydrosphingomyelin were investigated by infrared spectroscopy. Ca(2+)-concentration-dependent studies of the head group region revealed that, for both sphingolipids, Ca(2+) partially dehydrates some of the phosphate groups and binds to others. Ca(2+) affects the interface of each sphingolipid differently. In SM, Ca(2+) shifts the amide I' band to frequencies lower than those in dehydrated samples of SM alone. This could be attributed to the direct binding of Ca(2+) to carbonyl groups and/or strong tightening of interlipid H-bonds to levels beyond those in dehydrated samples of SM only. In contrast, Ca(2+) induces relatively minor dehydration around the amide groups of dihydrosphingomyelin and a slight enhancement of direct lipid-lipid interactions. Temperature-dependent studies reveal that 0.2 M Ca(2+) increases the transition temperature T(m) from 31.6 +/- 1.0 degrees C to 35.7 +/- 1.1 degrees C for SM and from 45.5 +/- 1.1 degrees C to 48.2 +/- 1.0 degrees C for dihydrosphingomyelin. Binding of Ca(2+) to some phosphate groups remains above T(m). The strength of the interaction is, however, weaker. This allows for the partial rehydration of these moieties. Similarly, above T(m), Ca(2+)-lipid and/or direct inter-lipid interactions are weakened and lead to the rehydration of amide groups