Chromium Differentially Affects Hydrogen Peroxide Distribution in Primary and Adventitious Roots of Arabidopsis thaliana L.

The post-embryonic growth of the Arabidopsis thaliana root system can be modified by different types of stress,such as sublethal concentrations of metals,which may induce the production of reactive oxygen species(ROS).In this study,the effects of different concentrations of potassium chromate(K_(2)CrO_(4))on the distribution and relative quantity of hydrogen peroxide(H_(2)O_(2))were determined in primary and adventitious roots in A.thaliana HyPer line seedlings.This line has a biosensor that specifically reports H_(2)O_(2) levels within tissues as fluorescence.Primary root growth was inhibited at 100μM Cr(VI);in contrast,adventitious root formation was induced over the main root growth axis.These structures proliferated from 100-160μM Cr(VI),and much higher concentrations(180-200μM)of K_(2)CrO_(4) were required to affect their growth.The H_(2)O_(2) distributions were observed in the columella and lateral root cap of primary roots of plants grown in medium lacking dichromate,but following the development of toxicity symptoms,H_(2)O_(2) changed its distribution to the meristem and differentiation zones.Conversely,adventitious roots had comparable H_(2)O_(2) distribution patterns in untreated plants and those exposed to Cr(VI)supplementation.Thus,differential H_(2)O_(2) distribution correlates with the resistance of adventitious roots,but not primary roots,to dichromate and underlies cell reorganization at the apex to support growth.

Sensory neurons in the spinal cord of nominal female embryos in the marine turtle Lepidochelys olivacea respond to shifts in incubation temperature:implications for temperature dependent sex determination

Gonadal determination in marine turtles depends on incubation temperature. The mechanisms that spark off this process remain unclear. Previously, we proposed that sensory nerves reaching the gonadal primordium in nominal female embryos of Lepidochelys (L) olivacea may sense and signal incubation temperature. These nerves could later trigger ovarian determination by releasing neurotransmitters in a code constructed based on the thermal information (Gutierrez-Ospina et al., Acetylcholinesterase-positive innervation is present at the undifferentiated stages of the sea turtle Lepidochelys olivacea embryo gonads: implications for temperature-dependent sex determination, J. Comp. Neurol. 410 (1999) 90-98). The hypothesis briefly described, however, has been recently refuted under weak theoretical grounds and experimental misinterpretations (see introduction). Here, we present preliminary results that show that nominal female embryos have sensory neurons located in the dorsal horn laminae I and II of the lumbar spinal cord that display increased c-Fos-like immuno-staining after being incubated either at 15°C or 50°C. Because these spinal neurons are the primary central target of dorsal root ganglion neurons that innervate the urogential crest, these observations keep open the possibility that gonadal sensory nerves indeed signal thermal information that could later be used to trigger or instruct ovarian specification in marine turtles.

Optimal diet strategy of a large-bodied psittacine: food resource abundance and nutritional content enable facultative dietary specialization by the Military Macaw

Background:Dietary specialization should arise when there is a relatively high abundance of a particular resource,where animals may select food items to obtain an optimal diet that maximizes energy intake.Large‑bodied psittacines frequently exhibit a narrow dietary niche with specific habitat use,but few studies have determined whether psittacines select food resources,and how this influences habitat use.Methods:We established fruiting phenology transects to evaluate food resource availability for the large‑bodied Military Macaw(Ara militaris)in semi‑deciduous,deciduous,and pine‑oak forest at two sites along the coast of Jalisco,during the dry season when macaws are nesting.We also determined Military Macaw diet by observations of foraging macaws along transect routes,and conducted bromatological analysis of the nutritional content of the most consumed resource.Results:Military Macaws used six plant species as food items during the dry season,and had a narrow dietary niche(Levins’B=0.28),with 56%of foraging macaws consuming the seeds of Hura polyandra.No food resources were recorded in pine‑oak forest during the dry season,with food resources and foraging by macaws concentrated in tropical deciduous and semi‑deciduous forest,where H.polyandra was the most abundant fruiting tree species.When considering the proportional availability of food resources,we determined a broad Hurlbert dietary niche breadth of H=0.67,indicating that Military Macaws consumed food resources according to their availability.Furthermore,the seeds of H.polyandra were an important source of protein,carbohydrates,minerals and moisture,and the hard fruitcasing means that these seeds are exclusively available for macaws.Conclusions:By concentrating their diet on the most abundant resources,Military Macaws may increase foraging efficiency in the dry season.The high nutrient content also means that concentrating the diet on seeds of H.polyandra may be an optimal foraging strategy for Military Macaws to meet their energy requirements during the breeding season.

Landscape genetics reveals inbreeding and genetic bottlenecks in the extremely rare short-globose cacti Mammillaria pectinifera (Cactaceae) as a result of habitat fragmentation

Mammillaria pectinifera is an endemic, short-globose cactus species, included in the IUCN list as a threatened species with only 18 remaining populations in the Tehuacán-Cuicatlán Valley in central Mexico. We evaluated the population genetic diversity and structure, connectivity, recent bottlenecks and population size, using nuclear microsatellites. M. pectinifera showed high genetic diversity but some evidence of heterozygote deficiency(F_(IS)), recent bottlenecks in some populations and reductions in population size. Also, we found low population genetic differentiation and high values of connectivity for M. pectinifera, as the result of historical events of gene flow through pollen and seed dispersal.M. pectinifera occurs in sites with some degree of disturbance leading to the isolation of its populations and decreasing the levels of gene flow among them. Excessive deforestation also changes the original vegetation damaging the natural habitats. This species will become extinct if it is not properly preserved.Furthermore, this species has some ecological features that make them more vulnerable to disturbance such as a very low growth rates and long life cycles. We suggest in situ conservation to prevent the decrease of population sizes and loss of genetic diversity in the natural protected areas such as the Tehuacán-Cuicatlán Biosphere Reserve. In addition, a long-term ex situ conservation program is need to construct seed banks, and optimize seed germination and plant establishment protocols that restore disturbed habitats. Furthermore, creating a supply of living plants for trade is critical to avoid further extraction of plants from nature.

Phosphorylated KDR can be located in the nucleus of neoplastic cells

KDR (kinase 插入领域受体) phosphorylation 导致最后带到房间增长和幸存的几效果。一旦它被激活， KDR 与原子核由交流的精确机制正在开始被理解，但是还没是完全 unravelled。二在在文学报导的动物细胞线上的 vitro 研究表明了那，跟随有 VEGF 的刺激， KDR 实际上是在原子核以内的 translocated。我们的目的是调查这 translocation 是否在 vitro 并且在 vivo 发生在人的房间。用扫描共焦的显微镜学的激光，在房间线和瘤样品的 phosphorylated 和全部的 KDR 的可变原子本地化被发现。在人的肿瘤的房间线， hypoxic 刺激极大地增加了全部的 KDR，但是少些的原子数量以便 phosphorylated 形式。仅仅在组织缺氧和 VEGF 刺激以后，有在这些房间的原子核观察的 phosphorylated 和全部的 KDR 的可比较地增加的表情。我们断定肿瘤的房间在原子核显示出总数和 phosphorylated KDR 的可变表情。要证实的原子地点遗体的精确功能的意思。

Vascular endothelial growth factor：an essential neurotrophic factor for motoneurons？

Vascular endothelial growth factor（VEGF）,an angiogenic factor with neuroprotective effects：The VEGF was initially characterized by its vasculogenic and angiogenic activities and its capacity to promote vascular permeability（Yancopoulos et al.,2000）.VEGF is also known as VEGF-A and is the prototype member of a related group of five trophic factors,VEGF-B,VEGF-C,VEGF-D and placental growth factor（Pl GF;Lange et al.,2016）.

Marine turtle hatchlings use multiple sensory cues to orient their crawling towards the sea:biological and conservation policy implications

The ability of sea turtle hatchlings to find the seashore soon after hatching is thought to be exclusively dependent upon visual information. Target-oriented movements in most vertebrates, however, relay on combining information gathered through different sensory systems. Hence, in this work, we investigated whether olfactory and/or magnetic information might complement visual cues during hatchling’s seaward crawling. Acute olfactory deprivation and distorted magnetic sensation in visually competent hatchlings resulted in a scattering of seaward crawling routes among cardinal points, some of them being different from those strongly preferred by control hatchlings. In addition, blindfolded hatchlings also displayed a striking misrouting while crawling on the beach surface in spite of having intact olfactory and magnetic senses. Together these results support the notion that visual information is crucial for seaward crawling, but also that olfactory and magnetic information complement visual cues when turtle hatchlings display this behavior. Hence, the present observations suggest that multisensory cues are used by turtle hatchlings while crawling towards the sea. This work also has important implications on the design of species conservation measures and policies. In the near future, efforts must be made to identify and preserve the local natural sources of odors and magnetic cues, in addition to preventing the perturbing effects of artificial lighting on adult and hatchling turtle crawling behavior.

Increased serotonin concentration and tryptophan hydroxylase activity in reproductive organs of copulator males:a case of adaptive plasticity

Individual male rats may systematically display or not copulatory behavior when paired with receptive females. Although these phenotypes are associated with differences in brain organization and function, they might also do so at the level of the reproductive organs. We then used high performance liquid chromatography to quantify serotonin concentration and the activity of tryptophan hydroxylase in the reproductive organs of copulator and non-copulator males. Sexual behavior display was compared between groups and parameters of fertility and reproductive fitness were determined for copulator males. Copulator males had higher concentrations of serotonin in the epididymis, testicle and ventral prostate than their non-copulator counterparts, as it was found for epididymal and testicular tryptophan hydroxylase activity. However, preliminary data shows that serotonin elevation occurs in copulator males only until they have accumulated several sexual encounters, so it might be a response to genital gratification or sexual rewarding. Interestingly, only epididymal serotonin concentration correlated with reproductive fitness, offspring number, mating success and seminal plug volume in copulator males. Our results support that copulator and non-copulator male rats feature a phenotype-specific serotoninergic tone in the epididymis, testicle and ventral prostate gland. The observation documenting that epididymal serotonin concentration correlated with parameters that monitor male fertility and reproductive fitness in copulator males predicts that epididymal factors increase their chances of parenting offspring.

Protein Shuttle between Nucleus and Cytoplasm:New Paradigms in the ABI5-dependent ABA Responses

Plant survival depends on seed germination,progression through post-germinative developmental checkpoints,and adaptation to abiotic stresses.All these processes underlie a tightly controlled regulation by the stress hormone abscisic acid(ABA)at different levels,even though the main research focuses on changes in transcript and protein abundance.Nevertheless,protein fate undergoes complex readjustments that allow signal transduction to be integrated into physiological responses.Among them,protein redox status,stability,capacity of oligomerization,formation of complexes,and subcellular compartmentalization become key points for plant reprogramming against stresses to acquire an optimal development.In this Spotlight,we highlight and discuss the latest advances in dissecting the mechanisms driving protein dynamics of nucleocytoplasmic trafficking in the cell and its relevance for regulating the stability of ABI5 and the ABI5-dependent AB A signaling pathway(Figure 1).

Wing morphology covaries with migration distance in a highly aerial insectivorous songbird

According to classical prediction of aerodynamic theory,birds and other powered fliers that migrate over long distances should have longer and more pointed wings than those that migrate less.However,the association between wing morphology and migratory behavior can be masked by contrasting selective pressures related to foraging behavior,habitat selection and predator avoidance,possibly at the cost of lower flight energetic efficiency.We studied the handwing morphology of Eurasian barn swallows Hirundo rustica from four populations representing a migration distance gradient.This species is an aerial insectivore,so it flies extensively while foraging,and may migrate during the day using a‘fly-and-forage’migration strategy.Prolonged foraging flights may reinforce the effects of migration distance on flight morphology.We found that two wings’aerodynamic properties—isometric handwing length and pointedness,both favoring energetically efficient flight,were more pronounced in barn swallows from populations undertaking longer seasonal migrations compared to less migratory populations.Our result contrast with two recent interspecific comparative studies that either reported no relationship or reported a negative relationship between pointedness and the degree of migratory behavior in hirundines.Our results may thus contribute to confirming the universality of the rule that longer migrations are associated with more pointed wings.

3种地中海橡树在叶脉和气孔性状上的个体发育性变化及其与叶片经济性状的关系

我们比较了3个地中海栎属(Quercus)树种幼苗和成龄树的叶脉和气孔性状。之前的研究表明,幼苗的气体交换率往往比成龄树的要高。我们的研究目标是确认叶脉和气孔的性状在整个植物个体发育过程中是否会随着气体交换率的变化而同步改变。我们提出了以下两个备选假设:幼苗比成龄树有着更高的叶脉和气孔密度(假设1);幼苗在维管组织上的投资更少,从而降低了建设成本(假设2)。本研究是在西班牙中西部进行的,我们对每个树种不同生长阶段的植株随机采集了10个样本。我们测量了气孔和叶脉的平均性状(单位叶面积里的气孔大小和数量、叶脉密度、叶脉体积、叶脉到表皮的距离),比叶质量和叶片厚度。研究结果表明,细脉密度和单位面积叶脉体积随着树龄的增加而增加,这似乎与气体交换率方面的个体发育趋势不一致。这种差异支持了我们的假设2,说明植株在幼苗阶段减少对维管组织的投资以最大限度地提高生长速度是其当务之急。幼苗叶片中较大的叶脉间距可以由叶脉到表皮的较短距离所补偿。因此,薄叶片可能是幼苗的一个必要性状,它可以让水分沿较短路径输送到蒸发点,而无需对高成本的维管组织进行大量投资。