Regulation of the Arabidopsis GSK3-like kinase BRASSINOSTEROID-INSENSITIVE 2 through proteasome-mediated protein degradation.

Glycogen synthase kinase 3 (GSK3) is a unique serine/threonine kinase that is implicated in a variety of cellular processes and is regulated by phosphorylation or protein-protein interaction in animal cells. BIN2 is an Arabidopsis GSK3-like kinase that negatively regulates brassinosteroid (BR) signaling. Genetic studies suggested that BIN2 is inhibited in response to BR perception at the cell surface to relieve its inhibitory effects on downstream targets; however, little is known about biochemical mechanisms of its inhibition.

Chordate metamorphosis: ancient control by iodothyronines.

A new study shows that iodothyronines induce metamorphosis in the cephalochordate amphioxus by binding to a receptor homologous to vertebrate thyroid hormone receptors. Iodothyronine-induced metamorphosis may be an ancestral feature of the chordates.

Regulation of the feedback antagonist naked cuticle by Wingless signaling.

Signaling pathways usually activate transcriptional targets in a cell type-specific manner. Notable exceptions are pathway-specific feedback antagonists, which serve to restrict the range or duration of the signal. These factors are often activated by their respective pathways in a broad array of cell types.

Indirect interactions between ant-tended hemipterans, a dominant ant Azteca instabilis (Hymenoptera: Formicidae), and shade trees in a tropical agroecosystem.

The occurrence, intensity, and composition of mutualisms are dependent not only on the co-occurrence of mutualists, but also the broader biotic context in which they are embedded. Here, the influence of the specific nest tree identity of the ant Azteca instabilis (F. Smith) on the density of the green coffee scale (Coccus viridis Green) was studied in a coffee agroecosystem in southern Mexico.

Malaria transmission pattern resilience to climatic variability is mediated by insecticide-treated nets.

Background: Malaria is an important public-health problem in the archipelago of Vanuatu and climate has been hypothesized as important influence on transmission risk. Beginning in 1988, a major intervention using insecticide-treated bed nets (ITNs) was implemented in the country in an attempt to reduce Plasmodium transmission. To date, no study has addressed the impact of ITN intervention in Vanuatu, how it may have modified the burden of disease, and whether there were any changes in malaria incidence that might be related to climatic drivers.

Site-directed mutagenesis of conserved C-terminal tyrosine and tryptophan residues of PsbO, the photosystem II manganese-stabilizing protein, alters its activity and fluorescence properties.

The extrinsic photosystem II PsbO subunit (manganese-stabilizing protein) contains near-UV CD signals from its complement of aromatic amino acid residues (one Trp, eight Tyr, and 13 Phe residues). Acidification, N-bromosuccinimide modification of Trp, reduction or elimination of a disulfide bond, or deletion of C-terminal amino acids abolishes these signals. Site-directed mutations that substitute Phe for Trp241 and Tyr242, near the C-terminus of PsbO, were used to examine the contribution of these residues to the activity and spectral properties of the protein.

Oxidation of ingested phenolics in the tree-feeding caterpillar Orgyia leucostigma depends on foliar chemical composition.

Tannins are believed to function as antiherbivore defenses, in part, by acting as prooxidants. However, at the high pH found in the midguts of caterpillars, the oxidative activities of different types of tannins vary tremendously: ellagitannins >> galloyl glucoses > condensed tannins. Ingested ascorbate is utilized by caterpillars to minimize phenolic oxidation in the midgut.

Inactive methyl indole-3-acetic acid ester can be hydrolyzed and activated by several esterases belonging to the AtMES esterase family of Arabidopsis.

The plant hormone auxin (indole-3-acetic acid [IAA]) is found both free and conjugated to a variety of carbohydrates, amino acids, and peptides. We have recently shown that IAA could be converted to its methyl ester (MeIAA) by the Arabidopsis (Arabidopsis thaliana) enzyme IAA carboxyl methyltransferase 1. However, the presence and function of MeIAA in vivo remains unclear.

The ArgP protein stimulates the Klebsiella pneumoniae gdhA promoter in a lysine-sensitive manner.

The lysine-sensitive factor that binds to the upstream region of the Klebsiella pneumoniae gdhA promoter and stimulates gdhA transcription during growth in minimal medium has been proposed to be the K. pneumoniae ArgP protein (M. R.

Distribution and corticosteroid regulation of glucocorticoid receptor in the brain of Xenopus laevis.

Glucocorticoids (GCs) play essential roles in physiology, development, and behavior that are mediated largely by the glucocorticoid receptor (GR). Although the GR has been intensively studied in mammals, very little is known about the GR in nonmammalian tetrapods. We analyzed the distribution and GC regulation of GR in the brain of the frog Xenopus laevis by immunohistochemistry.

Probing interactions between plant virus movement proteins and nucleic acids.

Most plant viruses move between plant cells with the help of their movement proteins (MPs). MPs are multifunctional proteins, and one of their functions is almost invariably binding to nucleic acids. Presumably, the MP-nucleic acid interaction is directly involved in formation of nucleoprotein complexes that function as intermediates in the cell-to-cell transport of many plant viruses.

Phylogenetic analysis of the incidence of lux gene horizontal transfer in Vibrionaceae.

Horizontal gene transfer (HGT) is thought to occur frequently in bacteria in nature and to play an important role in bacterial evolution, contributing to the formation of new species. To gain insight into the frequency of HGT in Vibrionaceae and its possible impact on speciation, we assessed the incidence of interspecies transfer of the lux genes (luxCDABEG), which encode proteins involved in luminescence, a distinctive phenotype. Three hundred three luminous strains, most of which were recently isolated from nature and which represent 11 Aliivibrio, Photobacterium, and Vibrio species, were screened for incongruence of phylogenies based on a representative housekeeping gene (gyrB or pyrH) and a representative lux gene (luxA).

Disulfide bond isomerization in prokaryotes.

Proteins with multiple cysteine residues often require disulfide isomerization reactions before they attain their correct conformation. In prokaryotes this reaction is catalyzed mainly by DsbC, a protein that shares many similarities in structure and mechanism to the eukaryotic protein disulfide isomerase. This review discusses the current knowledge about disulfide isomerization in prokaryotes.

Development of motor networks in zebrafish embryos.

General mechanisms of motor network development have often been examined in the spinal cord because of its relative simplicity when compared to higher parts of the brain. Indeed, most of our current understanding of motor pattern generation comes from work in the lower vertebrate spinal cord. Nevertheless, very little is known about the initial stages of motor network formation and the interplay between genes and electrical activity.

The multiple phenylpropene synthases in both Clarkia breweri and Petunia hybrida represent two distinct protein lineages.

Many plants synthesize the volatile phenylpropene compounds eugenol and isoeugenol to serve in defense against herbivores and pathogens and to attract pollinators. Clarkia breweri flowers emit a mixture of eugenol and isoeugenol, while Petunia hybrida flowers emit mostly isoeugenol with small amounts of eugenol. We recently reported the identification of a petunia enzyme, isoeugenol synthase 1 (PhIGS1) that catalyzes the formation of isoeugenol, and an Ocimum basilicum (basil) enzyme, eugenol synthase 1 (ObEGS1), that produces eugenol.

Evolutionarily conserved glucocorticoid regulation of corticotropin-releasing factor expression.

Glucocorticoids (GCs) exert feedback regulation on corticotropin-releasing factor (CRF) neurons in mammals. The nature of GC actions is cell-type specific, being either inhibitory (e.g.

Spenito and Split ends act redundantly to promote Wingless signaling.

Wingless (Wg)/Wnt signaling directs a variety of cellular processes during animal development by promoting the association of Armadillo/beta-catenin with TCFs on Wg-regulated enhancers (WREs). Split ends (Spen), a nuclear protein containing RNA recognition motifs (RRMs) and a SPOC domain, is required for optimal Wg signaling in several fly tissues. In this report, we demonstrate that Spenito (Nito), the only other fly protein containing RRMs and a SPOC domain, acts together with Spen to positively regulate Wg signaling.

Molecular mechanism of mitotic Golgi disassembly and reassembly revealed by a defined reconstitution assay.

In mammalian cells, flat Golgi cisternae closely arrange together to form stacks. During mitosis, the stacked structure undergoes a continuous fragmentation process. The generated mitotic Golgi fragments are distributed into the daughter cells, where they are reassembled into new Golgi stacks.

Reclassification of Vibrio fischeri, Vibrio logei, Vibrio salmonicida and Vibrio wodanis as Aliivibrio fischeri gen. nov., comb. nov., Aliivibrio logei comb. nov., Aliivibrio salmonicida comb. nov. and Aliivibrio wodanis comb. nov.

Four closely related species, Vibrio fischeri, Vibrio logei, Vibrio salmonicida and Vibrio wodanis, form a clade within the family Vibrionaceae; the taxonomic status and phylogenetic position of this clade have remained ambiguous for many years. To resolve this ambiguity, we tested these species against other species of the Vibrionaceae for phylogenetic and phenotypic differences. Sequence identities for the 16S rRNA gene were > or =97.

The implicit assumption of symmetry and the species abundance distribution.

Species abundance distributions (SADs) have played a historical role in the development of community ecology. They summarize information about the number and the relative abundance of the species encountered in a sample from a given community. For years ecologists have developed theory to characterize species abundance patterns, and the study of these patterns has received special attention in recent years.

Shifting patterns: malaria dynamics and rainfall variability in an African highland.

The long-term patterns of malaria in the East African highlands typically involve not only a general upward trend in cases but also a dramatic increase in the size of epidemic outbreaks. The role of climate variability in driving epidemic cycles at interannual time scales remains controversial, in part because it has been seen as conflicting with the alternative explanation of purely endogenous cycles exclusively generated by the nonlinear dynamics of the disease. We analyse a long temporal record of monthly cases from 1970 to 2003 in a highland of western Kenya with both a time-series epidemiological model (time-series susceptible-infected-recovered) and a statistical approach specifically developed for non-stationary patterns.

Evolutionary genetics: how flies get naked.

Researchers studying evolution of 'naked' (hairless) larval cuticle in Drosophila sechellia have discovered surprising complexity in the pattern of cis-regulatory differences that differentiate this species from its 'hairy' ancestors.

Do inbreeding depression and relative male fitness explain the maintenance of androdioecy in white mangrove, Laguncularia racemosa (Combretaceae)?

Mathematical models predict that to maintain androdioecious populations, males must have at least twice the fitness of male function in hermaphrodites. To understand how androdioecy is maintained in Laguncularia racemosa (white mangrove), outcrossing, inbreeding depression, and relative male fitness were estimated in two androdioecious populations and one hermaphroditic population. Outcrossing was estimated based on length of pollinator foraging bout and pollen carryover assumptions.

Individual recognition: it is good to be different.

Individual recognition (IR) behavior has been widely studied, uncovering spectacular recognition abilities across a range of taxa and modalities. Most studies of IR focus on the recognizer (receiver). These studies typically explore whether a species is capable of IR, the cues that are used for recognition and the specializations that receivers use to facilitate recognition.