Cux1 and Cux2 selectively target basal and apical dendritic compartments of layer II‐III cortical neurons

A number of recent reports implicate the differential regulation of apical and basal dendrites in autism disorders and in the higher functions of the human brain. They show that apical and basal dendrites are functionally specialized and that mechanisms regulating their development have important consequences for neuron function. The molecular identity of layer II‐III neurons of the cerebral cortex is determined by the overlapping expression of Cux1 and Cux2. We previously showed that both Cux1 and Cux2 are necessary and nonredundant for normal dendrite development of layer II‐III neurons. Loss of function of either gene reduced dendrite arbors, while overexpression increased dendritic complexity and suggested additive functions. We herein characterize the function of Cux1 and Cux2 in the development of apical and basal dendrites. By in vivo loss and gain of function analysis, we show that while the expression level of either Cux1 or Cux2 influences both apical and basal dendrites, they have distinct effects. Changes in Cux1 result in a marked effect on the development of the basal compartment whereas modulation of Cux2 has a stronger influence on the apical compartment. These distinct effects of Cux genes might account for the functional diversification of layer II‐III neurons into different subpopulations, possibly with distinct connectivity patterns and modes of neuron response. Our data suggest that by their differential effects on basal and apical dendrites, Cux1 and Cux2 can promote the integration of layer II‐III neurons in the intracortical networks in highly specific ways. © 2014 Wiley Periodicals, Inc. Develop Neurobiol 75: 163–172, 2015     

Kupffer cell-derived prostaglandin E2 is involved in regulation of lipid synthesis in rat liver tissue

Our recent studies suggest that Kupffer cells play a role in the physiological regulation of lipid metabolism of the adjacent hepatocytes. In the present study, we have tested the hypothesis that inhibition of Kupffer cells decreases prostaglandin E(2) (PGE(2)) release inside liver tissue, a phenomenon contributing to lipid accumulation in hepatocytes. PGE(2) secretion as well as lipid synthesis were assessed in precision-cut liver slices (PCLS) from rats previously treated with Kupffer cell inhibitors (GdCl(3) 10 mg kg(-1) body wt, i.v. injection and glycine 5% in diet). In addition, lipid synthesis was assessed in primary rat hepatocytes cultured in the absence or presence of PGE(2) (0.01, 1 and 10 microM). Inhibition of Kupffer cell activity by GdCl(3) decreases PGE(2) secretion by PCLS and resulted in a higher lipid synthesis. Since incubation with PGE(2) over 48 h decreases lipid synthesis from acetate in cultured hepatocytes, we propose that the lower PGE(2) secretion linked to Kupffer cell inhibition, partly explains a higher rate of synthesis of lipids with a subsequent accumulation in liver tissue, as previously shown in fasted rats.     

Meat-eating by early hominids at the FLK 22Zinjanthropussite, Olduvai Gorge (Tanzania): an experimental approach using cut-mark data

The meat-eating behavior of Plio-Pleistocene hominids, responsible for the bone accumulations at the earliest archaeological sites, is still a hotly-debated issue in paleoanthropology. In particular, meat-eating and bone marrow consumption are often presented as either complementary or opposing strategies of carcass exploitation. The presence of cut marks on fossil archeofauna is a potential source of information that has not been consistently used as evidence of carcass consumption by hominids. Some authors interpret cut marks as the result of hominids manipulating meat-bearing bones, while others argue that they can also be the result of hominids extracting marginal scraps of carcass flesh that have survived carnivores’ initial consumption. In this study, a referential framework concerning the interpretation of cut marks is presented, based on a set of experiments conducted by the author. It is suggested, according to these experiments and data drawn from the FLK “Zinj” site, that hominids processed meat-bearing bones (on which flesh was abundant) rather than defleshed carcasses from felid kills.     

郁金香切花瓶插期的衰老与膜脂过氧化的关系

郁金香鲜切花在瓶插过程中,叶片可溶性蛋白质含量从瓶插开始即开始下降,花瓣在瓶插初期略有上升,第３天以后随花朵的开放迅速下降。叶片、花瓣的可溶性蛋白质含量的下降与细胞膜相对透性的增加呈负相关,与ＭＤＡ含量的增加呈负相关;而细胞膜相对透性的增加与ＭＤＡ含量的增加呈正相关。同时,饱和脂肪酸所占百分比增加,不饱和脂肪酸含量下降。ＩＵＦＡ的下降与ＭＤＡ含量的增加呈负相关。在整个瓶插过程中,花瓣的可溶性蛋白质     

Root nitrogen concentration of sorghum above 2% produces least Striga hermonthica seed stimulation

A series of pot and laboratory experiments was carried out to assess the effects of N status of sorghum roots and timing of N application (as NH₄NO₃) on the germination of Striga hermonthica seeds. Root N concentrations varied from 10 to 26 mg N g^?1. The cut root and the root exudates technique used in assaying S. hermonthica seed germination gave similar results. However, the cut root technique was easier to handle and more discriminating at low germination levels. S. hermonthica seed germination per unit sorghum root mass followed a broken‐stick model. It decreased with increasing root N concentrations, reaching lowest levels at a root N concentration of 19.5 mg N g^?1, after which no further reduction occurred. It was not possible to reduce S. hermonthica seed germination to a zero level. Timing of N application influenced the time a higher N concentration is reached, not the S. hermonthica seed germination. Both timing and rate of N application are important in maintaining root N concentrations above 19.5 mg N g^?1, thereby potentially reducing S. hermonthica germination in the field. Translation of results to reductions in infection levels and yield losses is hampered by density‐dependent relations after the S. hermonthica germination stage.     

The effect of forest age and habitat structure on the ground‐dwelling ant assemblages of lowland poplar plantations

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