Ant versus bird exclusion effects on the arthropod assemblage of an organic citrus grove

1. Predation‐exclusion experiments have highlighted that top‐down control is pervasive in terrestrial communities, but most of these experiments are simplistic in that they only excluded a single group of predators and the effect of removal was evaluated on a few species from the community. The main goal of our study was to experimentally establish the relative effects of ants and birds on the same arthropod assemblage of canopy trees. 2. We conducted 1‐year long manipulative experiments in an organic citrus grove intended to quantify the independent effects of bird and ant predators on the abundance of arthropods. Birds were excluded with plastic nets whereas ants were excluded with sticky barriers on the trunks. The sticky barrier also excluded other ground dwelling insects, like the European earwig Forficula auricularia L. 3. Both the exclusion of ants and birds affected the arthropod community of the citrus canopies, but the exclusion of ants was far more important than the exclusion of birds. Indeed, almost all groups of arthropods had higher abundance in ant‐excluded than in control trees, whereas only dermapterans were more abundant in bird‐excluded than in control trees. A more detailed analysis conducted on spiders also showed that the effect of ant exclusion was limited to a few families rather than being widespread over the entire diverse spectrum of spiders. 4. Our results suggest that the relative importance of vertebrate and invertebrate predators in regulating arthropod populations largely depends on the nature of the predator–prey system.     

Two closely linked tomato HKT coding genes are positional candidates for the major tomato QTL involved in Na+/K+ homeostasis

The location of major quantitative trait loci (QTL) contributing to stem and leaf [Na⁺] and [K⁺] was previously reported in chromosome 7 using two connected populations of recombinant inbred lines (RILs) of tomato. HKT1;1 and HKT1;2, two tomato Na⁺‐selective class I‐HKT transporters, were found to be closely linked, where the maximum logarithm of odds (LOD) score for these QTLs located. When a chromosome 7 linkage map based on 278 single‐nucleotide polymorphisms (SNPs) was used, the maximum LOD score position was only 35 kb from HKT1;1 and HKT1;2. Their expression patterns and phenotypic effects were further investigated in two near‐isogenic lines (NILs): 157‐14 (double homozygote for the cheesmaniae alleles) and 157‐17 (double homozygote for the lycopersicum alleles). The expression pattern for the HKT1;1 and HKT1;2 alleles was complex, possibly because of differences in their promoter sequences. High salinity had very little effect on root dry and fresh weight and consequently on the plant dry weight of NIL 157‐14 in comparison with 157‐17. A significant difference between NILs was also found for [K⁺] and the [Na⁺]/[K⁺] ratio in leaf and stem but not for [Na⁺] arising a disagreement with the corresponding RIL population. Their association with leaf [Na⁺] and salt tolerance in tomato is also discussed.     

Haptoglobin and CCR2 receptor expression in ovarian cancer cells that were exposed to ascitic fluid: Exploring a new role of haptoglobin in the tumoral microenvironment

Haptoglobin (Hp) is an acute-phase protein that is produced by the liver to capture the iron that is present in the blood circulation, thus avoiding its accumulation in the blood. Moreover, Hp has been detected in a wide variety of tissues, in which it performs various functions. In addition, this protein is considered a potential biomarker in many diseases, such as cancer, including ovarian carcinoma; however, its participation in the cancerous processes has not yet been determined. The objective of this work was to demonstrate the expression of Hp and its receptor CCR2 in the ovarian cancer cells and its possible involvement in the process of cell migration through changes in the rearrangement of the actin cytoskeleton using western blot and wound-healing assays and confirming by confocal microscopy. Ovarian cancer cells express both Hp and its receptor CCR2 but only after exposure to ascitic fluid, inducing moderated cell migration. However, when the cells are exposed to exogenous Hp, the expression of CCR2 is induced together with drastic changes in the actin cytoskeleton rearrangement. At the same time, Hp induced cell migration in a much more efficient manner than did ascitic fluid. These effects were blocked when the CCR2 synthetic antagonist RS102895 was used to pretreat the cells. These results suggest that Hp-induced changes in the cell morphology, actin cytoskeleton structure, and migration ability of tumor cells, is possibly “preparing” these cells for the potential induction of the metastatic phenotype.     

Thermostability of DNA and its connection with the glassing process

Using differential scanning calorimetry, the thermal denaturation of calf thymus DNA with different content of water (from 12 to 92%) was investigated. Dependences of melting temperature and enthalpy on the biopolymer hydration degree were established. Within the range of water concentrations from 92 to 50% the values of thermodynamic parameters of denaturation were obtained being in good agreement with the published data. Besides, a calorimetric manifestation of renaturation process at different cooling conditions after denaturation was studied. Special attention was paid to thermal properties of denatured and native DNA in the samples containing only the bound water. The temperature dependence of heat capacity in the denatured samples, which have completely lost their renaturation ability due to the proper thermal treatment, demonstrated a characteristic jump of thermal capacity. The value of this jump has been determined to be equal to 1.0 cal/g. degree C, related to dry weight, and almost not dependent on humidity. Temperature position of the jump (Tg) depends on the content of water which serves as a plasticizer. It is shown that the observed anomaly demonstrates all the properties characteristic of vitrification process in synthetic polymers and proteins. General similarity of thermal properties of the samples of native DNA, containing only the bound water, with those of denatured DNA also indicates a transition from the glassy into the rabber-like state. A possibility of existence of both native and denatured DNA in the glassy state at room temperature for the samples with low humidity (about 25%) has been demonstrated experimentally. It can be suggested that the formation of glassy state at dehydration of native DNA ensures its thermostability and the ability of restoration of its functional properties at a subsequent dehydration.     

中国高山ping亚属（Subgerus Alticola）的系统类与分布

高山ｐｉｎｇ亚属广布于中亚山地，即从喜马拉雅山、兴都库库会经帕米尔、天山、西茂而至图瓦、抗爱山和贝加尔湖一带。中国过去仅记录２种：银色高山ｐｉｎｇ（Ａｌｔｉｃｏｌａ ａｒｇｅｎｔａｔｃｓ Ｓｅｖｅｒｔｓｏｖ；有时定作劳氏高山ｐｉｎｇＡ．ｒｏｙｌｅｉ的一亚种）和斯氏高山ｐｉｎｇ。本文依据形态学资料和采用判别函数分析的方法，对该亚属进行了研究。我们认为中国高山ｐｉｎｇ至少有３个以上的物种存在，现概述于