Two diterpenes and three diterpene glucosides from Phlogacanthus curviflorus

Two new diterpene lactones, phlogacantholides B (1) and C (2), and three new diterpene lactone glucosides, phlogacanthosides A (3), B (4), and C (5), together with lupeol, beta-sitosterol, betulin, P-daucosterol, (+)syringaresinol, and (+)-syringaresinol-4-O-beta-D-glucopyranoside, were isolated from the roots of Phlogacanthus curviflorus. Their structures were elucidated by chemical and spectroscopic evidence. The structure, including the relative configuration of phlogacantholide B (1), was confirmed by X-ray crystallographic analysis of its diacetate (6)

Medaka piwi is Essential for Primordial Germ Cell Migration

Piwi controls the number of primordial germ cells (PGCs) via protecting maternal mRNA from decay and adult germ stem cell division in Drosophila. In mouse and zebrafish, piwi controls maintenance and differentiation of adult germ stem cell during gametogenesis. Whether piwi plays a role in PGC development of vertebrates remains unsolved. We addressed this issue by using medaka (Oryzias latipes) as a vertebrate model. Molecular cloning, sequence comparison and analyses of genomic organization and chromosome synteny led to the identification in this fish of a single piwi gene, called Opiwi. By RT-PCR analyses and in situ hybridization, the Opiwi transcript is maternally supplied and becomes restricted to PGCs and the central nervous system (CNS). Opiwi knockdown did not prevent PGC formation even in the absence of any somatic structures but did significantly reduce the number of PGCs in vivo and in vitro and affect the distribution of PGCs in developing embryos. Surprisingly, depletion of zygotic Opiwi severely and specifically affected PGC migration. We conclude that Opiwi is required not only for determining the PGC number but also for controlling PGC migration. Our results demonstrate that piwi plays a generally conserved role in germ cell development from Drosophila to vertebrate and a specific role in PGC migration.Piwi controls the number of primordial germ cells (PGCs) via protecting maternal mRNA from decay and adult germ stem cell division in Drosophila. In mouse and zebrafish, piwi controls maintenance and differentiation of adult germ stem cell during gametogenesis. Whether piwi plays a role in PGC development of vertebrates remains unsolved. We addressed this issue by using medaka (Oryzias latipes) as a vertebrate model. Molecular cloning, sequence comparison and analyses of genomic organization and chromosome synteny led to the identification in this fish of a single piwi gene, called Opiwi. By RT-PCR analyses and in situ hybridization, the Opiwi transcript is maternally supplied and becomes restricted to PGCs and the central nervous system (CNS). Opiwi knockdown did not prevent PGC formation even in the absence of any somatic structures but did significantly reduce the number of PGCs in vivo and in vitro and affect the distribution of PGCs in developing embryos. Surprisingly, depletion of zygotic Opiwi severely and specifically affected PGC migration. We conclude that Opiwi is required not only for determining the PGC number but also for controlling PGC migration. Our results demonstrate that piwi plays a generally conserved role in germ cell development from Drosophila to vertebrate and a specific role in PGC migration

Role of RhoA and rho kinase in lysophosphatidic acid-induced endothelial barrier dysfunction.

The online version of this article, along with updated information and services, is located on th

FERM Domain Interaction Promotes FAK Signaling

From the results of deletion analyses, the FERM domain of FAK has been proposed to inhibit enzymatic activity and repress FAK signaling. We have identified a sequence in the FERM domain that is important for FAK signaling in vivo. Point mutations in this sequence had little effect upon catalytic activity in vitro. However, the mutant exhibits reduced tyrosine phosphorylation and dramatically reduced Src family kinase binding. Further, the abilities of the mutant to transduce biochemical signals and to promote cell migration were severely impaired. The results implicate a FERM domain interaction in cell adhesion-dependent activation of FAK and downstream signaling. We also show that the purified FERM domain of FAK interacts with full-length FAK in vitro, and mutation of this sequence disrupts the interaction. These findings are discussed in the context of models of FAK regulation by its FERM domain

Sustainable food security in India—Domestic production and macronutrient availability

<div><p>India has been perceived as a development enigma: Recent rates of economic growth have not been matched by similar rates in health and nutritional improvements. To meet the second Sustainable Development Goal (SDG2) of achieving zero hunger by 2030, India faces a substantial challenge in meeting basic nutritional needs in addition to addressing population, environmental and dietary pressures. Here we have mapped—for the first time—the Indian food system from crop production to household-level availability across three key macronutrients categories of ‘calories’, ‘digestible protein’ and ‘fat’. To better understand the potential of reduced food chain losses and improved crop yields to close future food deficits, scenario analysis was conducted to 2030 and 2050. Under India’s current self-sufficiency model, our analysis indicates severe shortfalls in availability of all macronutrients across a large proportion (>60%) of the Indian population. The extent of projected shortfalls continues to grow such that, even in ambitious waste reduction and yield scenarios, enhanced domestic production alone will be inadequate in closing the nutrition supply gap. We suggest that to meet SDG2 India will need to take a combined approach of optimising domestic production and increasing its participation in global trade.</p></div

Cambridge Monographs in Experimental Biology

and the magnitude of FCT. Because active torque is proportional to n 2 and passive torque to n, the ratio of active to passive torque increases as n increases (Eq. 5), even while both quantities increase individuallẏ The increase in the ratio indicates an enhanced capability for active maneuvers and active stabilization, whereas the increase in FCT adds to passive stability. Thus, increasing wingbeat frequency enhances both maneuverability and stability. Hummingbirds provide an interesting example; males typically have greater wingbeat frequencies (21) and smaller body sizes as compared to females of the same species, potentially conferring a benefit in maneuverability and therefore an advantage in display flights (22) as well as greater stability when experiencing an external perturbation. These benefits are not without cost, because increasing wingbeat frequency increases the inertial and profile power requirements of flapping flight. Finally, the success of our FCT model in predicting yaw deceleration dynamics implies that passive damping may be important to flight control in flying animals across a wide range of body sizes. For example, if a steadily flapping animal experiences a brief perturbation in midstroke, by the time it is prepared to execute a corrective wingbeat, FCT will have eroded much of the effect of the perturbation, regardless of the wingbeat frequency employed by the animal. Thus, FCT provides open loop stability for some aspects of animal flight, reducing its neuromuscular and neurosensory requirements. These are not eliminated, because FCT results in asymmetric forces from symmetric flapping, implying that the animal&apos;s muscles must generate asymmetric forces and suggesting neural regulation to enforce symmetry. Furthermore, FCT does not address all the stability problems faced by flying animals. This study is limited to yaw dynamics in hovering or slow-speed flight; FCT is likely to be influential in fast forward flight, but no data are available to test such predictions. More important, a full description of body dynamics involves many factors beyond FCT and includes modes such as pitching and longitudinal dynamics known to be inherently unstable in open loop conditions (23, 24) and subject to active control (25, 26). Finally, yaw damping due to FCT is a feature of flapping flight that is not found in human-made fixed-wing or rotary-wing flyers and may lead to improvements in the stability and maneuverability of biomimetic micro-air vehicles. 11. S. P. Sane, J. Exp. Biol. 206, 4191 (2003). 12. J. R. Usherwood, C. P. Ellington, J. Exp. Biol. 205, 1565 Synonymous mutations do not alter the encoded protein, but they can influence gene expression. To investigate how, we engineered a synthetic library of 154 genes that varied randomly at synonymous sites, but all encoded the same green fluorescent protein (GFP). When expressed in Escherichia coli, GFP protein levels varied 250-fold across the library. GFP messenger RNA (mRNA) levels, mRNA degradation patterns, and bacterial growth rates also varied, but codon bias did not correlate with gene expression. Rather, the stability of mRNA folding near the ribosomal binding site explained more than half the variation in protein levels. In our analysis, mRNA folding and associated rates of translation initiation play a predominant role in shaping expression levels of individual genes, whereas codon bias influences global translation efficiency and cellular fitness. T he theory of codon bias posits that preferred codons correlate with the abundances of iso-accepting tRNAs (1, 2) and thereby increase translational efficiency (3) and accuracy (4). Recent experiments have revealed other effects of silent mutations (5-7). We synthesized a library of green fluorescent protein (GFP) genes that varied randomly in their codon usage, but encoded the same amino acid sequence (8). By placing these constructs in identical regulatory contexts and measuring their expression, we isolated the effects of synonymous variation on gene expression. The GFP gene consists of 240 codons. For 226 of these codons, we introduced random silent mutations in the third base position, while keeping the first and second positions constant We expressed the GFP genes in E. coli using a T7-promoter vector, and we quantified expression by spectrofluorometry. Fluorescence levels varied 250-fold across the library, and they were highly reproducible for each GFP construct (Spearman r = 0.98 between biological replicates)

A non-equilibrium sediment transport model for rill erosion

Sediment transport in rill flows exhibits the characteristics of non-equilibrium transport, and the sediment transport rate of rill flow gradually recovers along the flow direction by erosion. By employing the concept of partial equilibrium sediment transport from open channel hydraulics, a dynamic model of rill erosion on hillslopes was developed. In the model, a parameter, called the restoration coefficient of sediment transport capacity, was used to express the recovery process of sediment transport rate, which was analysed by dimensional analysis and determined from laboratory experimental data. The values of soil loss simulated by the model were in agreement with observed values. The model results showed that the length and gradient of the hillslope and rainfall intensity had different influences on rill erosion. Copyright (c) 2006 John Wiley & Sons, Ltd