Inductive interactions and embryonic equivalence groups in a basal metazoan, the ctenophore Mnemiopsis leidyi

Ctenophores undergo locomotion via the metachronal beating of eight longitudinally arrayed rows of comb plate cilia. These cilia are normally derived from two embryonic lineages, which include both daughters of the four e1 micromeres (e11 and e12) and a single daughter of the four m1 micromeres (the m12 micromeres). Although the e1 lineage is established autonomously, the m1 lineage requires an inductive interaction from the e1 lineage to contribute to comb plate formation. Successive removal of the e1 progeny at later stages of development indicates that this interaction takes place after the 32-cell stage and likely proceeds over a prolonged period of development. Normally, the e1, cell lies in closest proximity to the m12 cell that generates comb plate cilia; however, either of the e1 daughters (e11 or e12) is capable of emitting the signal required for m1 descendants to form comb plates. Previous cell lineage analyses indicate that the two e1 daughters generate the same suite of cell fates. On the other hand, the m1 daughters (m11 and m12) normally give rise to different cell fates. Reciprocal m1 daughter deletions show that in the absence of one daughter, the other cell can generate all the cell types normally formed by the missing cell. Together, these findings demonstrate that the two m1 daughters (m11 and m12) represent an embryonic equivalence group or field and that differences in the fates of the two m1 daughters are normally controlled by cell-cell interactions. These combined properties of ctenophore development, including the utilization of deterministic cleavage divisions, inductive interactions, and the establishment of embryonic fields or equivalence groups, are remarkably similar to those present in the development of various bilaterian metazoans.     

Paleovegetation and paleoclimate in middle-late Pliocene, Shanxi, central China

Sequences of lacustrine sediments developed in intermontane basins in the middle-eastern Shanxi Plateau of China have been investigated in order to reconstruct the paleovegetation and paleoclimate for the middle-late Pliocene. According to the magnetostratigraphy and the fossil assemblages, the lacustrine sediments of Yushe and Taigu Basins were deposited between 5.5 and 2.5 Ma BP. The Zhangcun and Xiaobai Formations are considered to cover a similar period, ranging from 3.5 to 2.5 Ma BP. An increase of Picea and Abies shows that the climate began to become cold after about 4.4 Ma BP. A cold-wet episode, with relatively warm-dry and warm-humid intervals, occurred between 3.6 and 2.5 Ma BP in the Yushe and Taigu Basins. An increase Artemisia, Chenopodiaceae and Ephedra shows that the climate became drier after 2.5 Ma BP. The climate changes of this period probably reflect variations of the East Asian winter and summer monsoons, with an increase winter monsoon activity during the early Pleistocene.     

Identification of a novel human Rho protein with unusual properties: GTPase deficiency and in vivo farnesylation.

We have identified a human Rho protein, RhoE, which has unusual structural and biochemical properties that suggest a novel mechanism of regulation. Within a region that is highly conserved among small GTPases, RhoE contains amino acid differences specifically at three positions that confer oncogenicity to Ras (12, 59, and 61). As predicted by these substitutions, which impair GTP hydrolysis in Ras, RhoE binds GTP but lacks intrinsic GTPase activity and is resistant to Rho-specific GTPase-activating proteins. Replacing all three positions in RhoE with conventional amino acids completely restores GTPase activity. In vivo, RhoE is found exclusively in the GTP-bound form, suggesting that unlike previously characterized small GTPases, RhoE may be normally maintained in an activated state. Thus, amino acid changes in Ras that are selected during tumorigenesis have evolved naturally in this Rho protein and have similar consequences for catalytic function. All previously described Rho family proteins are modified by geranylgeranylation, a lipid attachment required for proper membrane localization. In contrast, the carboxy-terminal sequence of RhoE predicts that, like Ras proteins, RhoE is normally farnesylated. Indeed, we have found that RhoE in farnesylated in vivo and that this modification is required for association with the plasma membrane and with an unidentified cellular structure that may play a role in adhesion. Thus, two unusual structural features of this novel Rho protein suggest a striking evolutionary divergence from the Rho family of GTPases.     

Studies on atrophic change of soleus muscle and its countermeasures in suspended rat

In the environment of microgravity, the disused atrophy of skeletal muscle, especially leg's muscle, would occur. The three purposes of this study were: 1. To observe the dynamic changes of disused atrophy of skeletal muscle under simulated weightlessness; 2. To approach the mechanism of disused atrophy of muscle; 3. To approach the countermeasures for reducing the degree of atrophy of muscle.     

The role of non-natural foods in the nutritional strategies of monkeys in a human-modified mosaic landscape

Many tropical animals inhabit mosaic landscapes including human-modified habitat. In such landscapes, animals commonly adjust feeding behavior, and may incorporate non-natural foods. These behavioral shifts can influence consumers' nutritional states, with implications for population persistence. However, few studies have addressed the nutritional role of non-natural food. We examined nutritional ecology of wild blue monkeys to understand how dietary habits related to non-natural foods might support population persistence in a mosaic landscape. We documented prevalence and nutritional composition of non-natural foods in monkey diets to assess how habitat use influenced their consumption, and their contribution to nutritional strategies. While most energy and macronutrients came from natural foods, subjects focused non-natural feeding activity on five exotic plants, and averaged about a third of daily calories from non-natural foods. Most non-natural food calories came from non-structural carbohydrates and least from protein. Consumption of non-natural foods related to time in human-modified habitats, which two groups used non-randomly. Non-natural and natural foods were similar in nutrients, and the amount of non-natural food consumed drove variation in nutritional strategy. When more daily calories came from non-natural foods, females consumed a higher ratio of non-protein energy to protein (NPE:P). Females also prioritized protein while allowing NPE:P to vary, increasing NPE while capitalizing on non-natural foods. Overall, these tropical mammals achieved a similar nutrient balance regardless of their intake of non-natural foods. Forest and forest-adjacent areas with non-natural vegetation may provide adequate nutrient access for consumers, and thus contribute to wildlife conservation in mosaic tropical landscapes.     

Screening of recombinant Escherichia coli using activation of green fluorescent protein as an indicator

A novel cloning vector that can be used to identify recombinant Escherichia coli colonies by activation of the green fluorescent protein gene (GFP) was constructed. Screening using the vector does not require special reagents. The recombinant plasmid activates GFP, and the rate of false-positive results is low.     

miR-27a is up regulated and promotes inflammatory response in sepsis

MicroRNAs (miRNAs) are short, non-coding RNAs that regulate the expression of multiple target genes. Dysregulation of miRNAs is common in sepsis. Through microRNA microarray and qRT-PCR we found that the levels of miR-27a, miR-153 and miR-143 are up regulated, while let-7a, miR-218 and miR-129-5p are down regulated in lungs of septic mice. Knocking down of miR-27a down regulates expression levels of TNF-α and IL-6 significantly via reducing the phosphorylation level of NF-κB p65 and inhibiting its DNA binding activity. Furthermore, neutralisation of miR-27a up regulates PPARγ level, down regulates TNF-α expression, relieves pulmonary inflammation and promotes survival of septic mice, which demonstrates that miR-27a plays an important role in regulating inflammatory response in sepsis and provides a potential target for clinical sepsis research and treatment.