2.8 million years of Arctic climate change from Lake El'gygytgyn, NE Russia

The reliability of Arctic climate predictions is currently hampered by insufficient knowledge of natural climate variability in the past. A sediment core from Lake El'gygytgyn in northeastern (NE) Russia provides a continuous, high-resolution record from the Arctic, spanning the past 2.8 million years. This core reveals numerous "super interglacials" during the Quaternary; for marine benthic isotope stages (MIS) 11c and 31, maximum summer temperatures and annual precipitation values are ~4° to 5°C and ~300 millimeters higher than those of MIS 1 and 5e. Climate simulations show that these extreme warm conditions are difficult to explain with greenhouse gas and astronomical forcing alone, implying the importance of amplifying feedbacks and far field influences. The timing of Arctic warming relative to West Antarctic Ice Sheet retreats implies strong interhemispheric climate connectivity.     

In Vitro Studies on Atrazine Effects on Human Intestinal Cells

Considering the importance of the oral route for human exposure to atrazine, we have investigated the possible effect of this herbicide on the human intestinal cells and the integrity of the epithelial barrier, using Caco-2 cells as the intestinal model in vitro. We evaluated possibile cytotoxic and genotoxic effects of atrazine in concentrations ranging from 1 to 250 μM on the Caco-2 cells at different stages of growth after short- and long-term exposure. Results from the tetrazolium blue (MTT) test and the Trypan blue exclusion assay showed that atrazine cytotoxicity was dose- and time-dependent. Obtained data indicated that atrazine at high concentrations (50 and 250 μM) was able to induce effects on Caco-2 proliferation and viability. Moreover, it was found that the long-term exposure to atrazine at the non-cytotoxic dose caused inhibition of the intestinal cell maturation and decreased the transepithelial electrical resistance, the indicator of the epithelial barrier integrity. Studies on the atrazine genotoxicity determined using the single cell microelectrophoresis assay indicated that atrazine did not induce DNA damages in the Caco-2 cells at concentrations of up to 50 μM, whereas enhancement in the DNA damage was observed at 250 μM. Altogether, our results indicate that atrazine at expected human oral exposure concentrations is not able to induce effects on the Caco-2 cell proliferation and viability, but may suppress the intestinal cell differentiation and reduce the cell monolayer integrity. We suggest that chronic exposure on low levels of atrazine may lead to alteration in the expression of the morphological and functional features of the Caco-2 cells related to the transport and barrier function of small intestinal enterocytes. In consequence, this may lead to alterations in the intestinal absorption process.     

Selected Uncommon Legumes as a Source of Essential Fatty Acids,Tocopherols, Tocotrienols,Sterols, Carotenoids,and Squalene

Plant Foods for Human Nutrition - The seeds of nine species belonging to the Fabaceae family (Cassia alata, Cassia uniflora, Cassia obtusifolia, Cassia tora, Crotalaria albida, Crotalaria juncea,...     

An analysis of isozymic loci polymorphism in the core collection of the Polish Pisum genebank

The investigated material consisted of the core collection of the Polish Pisum gene bank at Wiatrowo and represented a described, monohybrid variation (type lines for characters/genes and their initial lines, tester lines with markers and lines from wild taxa, 266 accessions in total). A polymorphism in 18 isozymic loci was analyzed (Lap-1, Px-1, Aat-p, Aat-m, Aat-c, Pgm-c, Pgm-p, Gpi-c, Idh, Acp-1, Skdh, Est-1, Est-2, Est-3, Aldo, 6Pgd-p, 6Pgd-c, Dia-1). The practical outcome of the analysis was a selection of lines with a high number of fast or slow isozymic alleles, useful as tester lines with markers for chromosome mapping. A polymorphism was stated in all investigated loci with 2 to 4 alleles ranging from very fast, fast, slow to very slow. Fast and slow alleles occurred in all loci. In 11 loci the incidence of fast alleles was higher than slow ones. Conversly, slow alleles occurred more frequently than fast ones in 5 loci. Additionally, there was a low incidence of a very fast allele in 7 loci and of a very slow allele in 3 loci. A slow allele was rare in 2 loci. Primitive lines and land races were a source of these rare alleles. It is suggested to consider a frequent allele of a given locus found in a group of wild lines as a so-called wild type of Pisum.     

Variability of fat content and fatty acids profiles in seeds of a Polish white lupin (<Emphasis Type="Italic">Lupinus albus</Emphasis> L.) collection

The paper assess the variability of fat content and fatty acids profiles in seeds of a white lupin (Lupinus albus L.) domestic collection. The initial material comprised 371 accessions originated from 30 countries of Europe, Asia, Africa, North- and South America and Australia. According to data given by accession donors the material is divided into four classes of origin: wild lines, landraces, lines created by man and cultivars. Variability of fat content and fatty acids composition were estimated in seeds of each accession. The average fat content for analyzed collection is 9.81%. The broadest range of fat content was noticed for landraces and cultivars as compared to narrowest represented by lines created by man. Fat content ranged from 6.9% (induced mutant Wt 95497) to 14.1% (Polish cultivar Wt 95420 and the landrace Wt 95212 from Jordan). From a dietetic point of view, oil quality is more important than oil quantity in lupin seeds. On average the fatty acid (FA) in examined accessions ranked in following order of abundance: oleic acid (C_18:1) > linoleic acid (C_18:2) > linolenic acid (C_18:3) > palmitic acid (C_16:0) > eicosenoic acid (C_20:1) > stearic acid (C_18:0) ≈ erucic acid (C_22:1). In respect to unsaturated fatty acid (UFA), monounsaturated oleic acid in each of estimated classes of accessions was predominant and most abundant (55.7%) in broad range of minimum–maximum values from 41.2 to 66.2%. The second examined monounsaturated fatty acid was erucic acid (1.74%) found in seeds of almost all studied accessions. An exception were four accessions defined similarly to rapeseeds as “zero erucic” forms. In seeds of few accessions a content of erucic acid exceeded 3%. Among polyunsaturated fatty acids linoleic FA (ω?6) dominated followed by linolenic FA (ω?3). Both FA were in the range 13.7–33.2% and 5.6–12.8% with mean values on the level 19.6 and 10.1%, respectively. As a consequence, the examined white lupin seeds showed a very favourable ω?3/ω?6 FA ratio (0.51), ranging from 0.21 to 0.87, much higher than that of most vegetable oils. Fat content was positively correlated with stearic and oleic fatty acids and negatively with palmitic, linoleic, linolenic and erucic acid.     

The health status and yield of winter rapeseed (Brassica napus L.) grown in monoculture and in crop rotation under different agricultural production systems

In a field experiment, winter rapeseed was grown in 5-year monoculture and in crop rotation (winter rapeseed, winter wheat, field peas, spring wheat and winter rapeseed). Two open-pollinated cultivars (Californium and Castille) and one hybrid cultivar (Nelson) were compared in systems with three levels of agricultural inputs, low input, medium input and high input, characterized by different rates of nitrogen and sulfur fertilization and pesticide use. The severity of sclerotinia rot (Sclerotinia sclerotiorum) and verticillium wilt (Verticillium spp.) on plants, dark spot (Alternaria spp.) and grey mold (Botrytis cinerea) on leaves and pods, as well as dry rot (Phoma lingam) on stems was evaluated during the growing season. The yield of winter rapeseed was calculated. Rapeseed grown after a 4-year break was characterized by less severe symptoms of dark spot on leaves and dry rot on stems, but more severe symptoms of grey mold on leaves and pods. The severity of dark spots on rapeseed pods (in crop rotation) was reduced with an increase in agricultural inputs. Cultivars Californium and Nelson were generally rarely infected by Verticillium spp., their leaves were less infected by Alternaria spp. and stems by Phoma spp. Nelson was the highest-yielding cultivar.     

Simultaneous selection for yield-related traits and susceptibility to Fusarium head blight in spring wheat RIL population

Fusarium head blight (FHB), caused by the fungal plant pathogen Fusarium, is a fungal disease that occurs in wheat and can cause significant yield and grain quality losses. The present paper examines variation in the resistance of spring wheat lines derived from a cross between Zebra and Saar cultivars. Experiments covering 198 lines and parental cultivars were conducted in three years, in which inoculation with Fusarium culmorum was applied. Resistance levels were estimated by scoring disease symptoms on kernels. In spite of a similar reaction of parents to F. culmorum infection, significant differentiation between lines was found in all the analyzed traits. Seven molecular markers selected as linked to FHB resistance QTLs gave polymorphic products for Zebra and Saar: Xgwm566, Xgwm46, Xgwm389, Xgwm533, Xgwm156, Xwmc238, and Xgwm341. Markers Xgwm389 and Xgwm533 were associated with the rate of Fusarium-damaged kernels (FDK) as well as with kernel weight per spike and thousand kernel weight in control plants. Zebra allele of marker Xwmc238 increased kernel weight per spike and thousand kernel weight both in control and infected plants, whereas Zebra allele of marker Xgwm566 reduced the percentage of FDK and simultaneously reduced the thousand kernel weight in control and infected plants.     

Phosphinothricin analogues as inhibitors of plant glutamine synthetases

A series of phosphinothricin derivatives with a modified methyl group, designed on the basis of the crystal structure of the complex formed by the inhibitor and the target enzyme from Salmonella typhimurium, were evaluated as potential inhibitors of plant glutamine synthetase. These compounds were previously shown to be equipotent or slightly weaker inhibitors to the lead compound against the bacterial enzyme. Because of the presence in higher plants of at least two enzyme forms with different subcellular localization and possible separate metabolic functions, plastidial and cytosolic glutamine synthetases were purified to electrophoretic homogeneity from spinach chloroplasts and cultured tobacco cells, respectively. Kinetic analysis confirmed the ability of the phosphinothricin analogues to inhibit both isoenzymes in the micromolar range, with a mechanism of a competitive type with respect to glutamate. Interestingly, some of them exerted a differential effect against either the two plant isoforms, or against the plant versus the bacterial enzyme.     

EFFECT OF PREHARVEST SPRAYS OF CALCIUM CHLORIDE AND SUCROSE ON CRACKING AND QUALITY OF ‘BURLAT’ SWEET CHERRY FRUIT

The aim of the study was to examine impact of preharvest sprays of calcium (Ca) and sucrose on splitting and quality of ‘Burlat’ sweet cherry fruit. The study was carried out during 2009–2010 in Poland and Turkey, on mature trees planted at a moderate density on coarse- and medium-textured soils. Sweet cherries were sprayed with calcium chloride (CaCl₂) and/or sucrose at a rate of 5 kg of each material per ha, using ca. 1000 L of water. In Poland, sprays of CaCl₂ and/or sucrose were applied 8–14 h before each rain, starting 21 d before harvest, whereas in Turkey the spray treatments were made schematically: 7, 14 and 21 d before harvest. Sprays of water were treated as the control. The results showed that preharvest sprays of CaCl₂ and/or sucrose did not affect yield, mean fruit weight, and fruit acidity. Sprays of CaCl₂ increased fruit Ca status, and simultaneously reduced fruit cracking in an orchard or laboratory test. In the trial performed in Turkey, part of fruit sprayed with CaCl₂ (<5%) had spray deposit on the peel. Sucrose sprays did not affect fruit cracking. In one year of the study in Turkey, sucrose sprays increased soluble solids concentration of fruit; however, part of fruit treated with sucrose (<2%) had spray deposit on the skin.