Coexistence of two Cyclotella diatom species in the plankton of Lake Baikal

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Fluoxetine potentiates the effects of corticotropin-releasing factor on locomotor activity and serotonergic systems in the roughskin newt, Taricha granulosa

The anxiety- and stress-related neuropeptide corticotropin-releasing factor (CRF) elicits behavioral changes in vertebrates including increases in behavioral arousal and locomotor activity. Intracerebroventricular injections of CRF in an amphibian, the roughskin newt (Taricha granulosa), induces rapid increases in locomotor activity in both intact and hypophysectomized animals. We hypothesized that this CRF-induced increase in locomotor activity involves a central effect of CRF on serotonergic neurons, based on known stimulatory actions of serotonin (5-hydroxytryptamine, 5-HT) on spinal motor neurons and the central pattern generator for locomotor activity in vertebrates. In Experiment 1, we found that neither intracerebroventricular injections of low doses of CRF (25 ng) nor the selective serotonin reuptake inhibitor fluoxetine (10, 100 ng), by themselves, altered locomotor activity. In contrast, newts treated concurrently with CRF and fluoxetine responded with marked increases in locomotor activity. In Experiment 2, we found that increases in locomotor activity following co-administration of CRF (25 ng) and fluoxetine (100 ng) were associated with decreased 5-HT concentrations in a number of forebrain structures involved in regulation of emotional behavior and emotional states, including the ventral striatum, amygdala pars lateralis, and dorsal hypothalamus, measured 37 min after treatment. These results are consistent with the hypothesis that CRF stimulates locomotor activity through activation of serotonergic systems.     

Apoptosis,cytokine and chemokine induction by non-structural 1 (NS1) proteins encoded by different influenza subtypes

Background

Influenza pandemic remains a serious threat to human health. Viruses of avian origin, H5N1, H7N7 and H9N2, have repeatedly crossed the species barrier to infect humans. Recently, a novel strain originated from swine has evolved to a pandemic. This study aims at improving our understanding on the pathogenic mechanism of influenza viruses, in particular the role of non-structural (NS1) protein in inducing pro-inflammatory and apoptotic responses.

Methods

Human lung epithelial cells (NCI-H292) was used as an in-vitro model to study cytokine/chemokine production and apoptosis induced by transfection of NS1 mRNA encoded by seven infleunza subtypes (seasonal and pandemic H1, H2, H3, H5, H7, and H9), respectively.

Results

The results showed that CXCL-10/IP10 was most prominently induced (> 1000 folds) and IL-6 was slightly induced (< 10 folds) by all subtypes. A subtype-dependent pattern was observed for CCL-2/MCP-1, CCL3/MIP-1α, CCL-5/RANTES and CXCL-9/MIG; where induction by H5N1 was much higher than all other subtypes examined. All subtypes induced a similar temporal profile of apoptosis following transfection. The level of apoptosis induced by H5N1 was remarkably higher than all others. The cytokine/chemokine and apoptosis inducing ability of the 2009 pandemic H1N1 was similar to previous seasonal strains.

Conclusions

In conclusion, the NS1 protein encoded by H5N1 carries a remarkably different property as compared to other avian and human subtypes, and is one of the keys to its high pathogenicity. NCI-H292 cells system proves to be a good in-vitro model to delineate the property of NS1 proteins.

     

Secondary Structure and Dynamics of an Intrinsically Unstructured Linker Domain

Abstract

The transient secondary structure and dynamics of an intrinsically unstructured linker domain from the 70 kDa subunit of human replication protein A was investigated using solution state NMR. Stable secondary structure, inferred from large secondary chemical shifts, was observed for a segment of the intrinsically unstructured linker domain when it is attached to an N-terminal protein interaction domain. Results from NMR relaxation experiments showed the rotational diffusion for this segment of the intrinsically unstructured linker domain to be correlated with the N-terminal protein interaction domain. When the N-terminal domain is removed, the stable secondary structure is lost and faster rotational diffusion is observed. The large secondary chemical shifts were used to calculate phi and psidihedral angles and these dihedral angles were used to build a backbone structural model. Restrained molecular dynamics were performed on this new structure using the chemical shift based dihedral angles and a single NOE distance as restraints. In the resulting family of structures a large, solvent exposed loop was observed for the segment of the intrinsically unstructured linker domain that had large secondary chemical shifts.     

Revision of Plerandra (Araliaceae). I. A synopsis of the genus with an expanded circumscription and a new infrageneric classification

Phylogenetic studies have demonstrated that Schefflera, the largest genus of Araliaceae, is grossly polyphyletic, comprising five distinct clades within the family. In an effort to establish monophyletic genera among the elements that currently comprise Schefflera, the genus Plerandra is expanded to encompass all of the members of one of these clades. In this synoptical revision, a new infrageneric classification is presented (along with a key) in which six subgenera are recognized. Four of these subgenera are newly described (Plerandra subgenera Canacoschefflera, Costatae, Gabriellarum, and Veilloniorum) and a fifth represents a new combination (Plerandra subg. Dizygotheca). A total of 33 species (one with two subspecies) are accepted, one of which is newly described (P. veilloniorum), and 22 new combinations are made (P. actinostigma, P. baillonii, P. cabalionii, P. costata, P. crassipes, P. elegantissima, P. elongata, P. emiliana, P. gabriellae, P. leptophylla, P. nono, P. osyana, P. osyana subsp. toto, P. pachyphylla, P. pancheri, P. plerandroides, P. polydactylis, P. reginae, P. seemanniana, P. tannae, P. vanuatua, P. veitchii). Neotypes are provided for six accepted names and one heterotypic synonym, and lectotypes are designated for 13 accepted names and 16 heterotypic synonyms. For each accepted species, full synonymy is provided along with geographic range and notes.     

Climatic impact,future biomass production,and local adaptation of four switchgrass cultivars

Previous studies have shown that switchgrass has a wide range of genetic variation and that productivity is linked to local adaptation to the location of origin for many cultivars. In this meta‐analysis, we compiled and analyzed 900 observations associated with 41 field trials for four switchgrass cultivars (two lowlands, Alamo and Kanlow, and two uplands, Cave‐In‐Rock and Shelter). This extensive dataset and machine learning were used to identify the most influential variables impacting switchgrass productivity, to search for evidence of local adaptation to each cultivar's location of origin, and to predict change in productivity under future climate for each cultivar. In general, variables associated with climate and management are more important predictors of productivity relative to soil variables. Three climatic variables, annual mean temperature, annual precipitation, and precipitation in the wettest month, are identified as key environmental variables for productivity of all cultivars. Productivity under future climate (2041–2060) is predicted to stay stable for all cultivars relative to the prediction under current climate (1986–2005) across all trial locations and over a 20‐year simulation period. However, the productivity of each cultivar varies from location to location and from year to year, although productivity varies more between locations than between years. Additionally, we observe shifts in the most productive cultivar at the local field scale depending on the combination of management practice and climates. The shape of the relationship between productivity and the annual mean temperature relative to the cultivar's location of origin is a bell‐shaped curve for Kanlow, Cave‐in‐Rock, and Shelter, indicative of local adaptation. Identifying influential environmental variables and their relationships to productivity with respect to cultivar's location of origin help predicting productivity on the local field scale, and will help with the biofuel production planning through the selection of suitable cultivars for different locations under climate changes.     

The Rox1 repressor of the Saccharomyces cerevisiae hypoxic genes is a specific DNA-binding protein with a high-mobility-group motif.

The ROX1 gene encodes a repressor of the hypoxic functions of the yeast Saccharomyces cerevisiae. The DNA sequence of the gene was determined and found to encode a protein of 368 amino acids. The amino-terminal third of the protein contains a high-mobility-group motif characteristic of DNA-binding proteins. To determine whether the Rox1 repressor bound DNA, the gene was expressed in Escherichia coli cells as a fusion to the maltose-binding protein and this fusion was partially purified by amylose affinity chromatography. By using a gel retardation assay, both the fusion protein and Rox1 itself were found to bind specifically to a synthetic 32-bp DNA containing the hypoxic consensus sequence. We assessed the role of the general repressor Ssn6 in ANB1 repression. An ANB1-lacZ fusion was expressed constitutively in an ssn6 deletion strain, and deletion of the Rox1 binding sites in the ANB1 upstream region did not increase the level of derepression, suggesting that Ssn6 exerts its effect through Rox1. Finally, ROX1 was mapped to yeast chromosome XVI, near the ARO7-OSM2 locus.     

Measurement of 2-deoxyglucose and 2-deoxyglucose 6-phosphate in tissues

The enzymatic methods previously described for 2-deoxyglucose (DG) and 2-deoxyglucose 6-phosphate have been refined and adapted to measurements of brain samples ranging from 50 mg wet weight to less than a microgram dry weight. Procedures for preparing such samples for assay are described. Analytical properties of the enzymes employed are given together with means for overcoming their possible short comings. Emphasis is placed on information useful for employing DG to assess rapid changes in glucose metabolism.     

Regional and subcellular distribution of enzymes of branched-chain amino acid metabolism in brains of normal and diabetic rats

Branched-chain-amino-acid:alpha-ketoglutarate transaminase and branched-chain alpha-ketoacid dehydrogenase have been assayed in brains of control and of streptozotocin-induced diabetic rats. Enzyme activities were measured in five distinct regions of the brain: cerebellum, pons + medulla, midbrain, thalamus + hypothalamus, and telencephalon. Subcellular distribution of these enzymes in whole brain was assessed by fractionating brain homogenate into cytoplasm, free mitochondria, and synaptosomes. The following enzymes were used as markers: lactate dehydrogenase for cytoplasm, glutamate dehydrogenase for mitochondria, and glutamate decarboxylase for synaptosomes. The activity of the branched-chain amino acid transaminase in all brain regions was considerably higher than that of the branched-chain alpha-ketoacid dehydrogenase. While the highest activity of the transaminase occurred in brain-stem regions, the highest activity of the dehydrogenase was present in cerebellum and telencephalon. Diabetes did not affect the activity of the transaminase, but it caused a decrease in the total activity of the dehydrogenase in midbrain and in thalamus + hypothalamus. The transaminase was localized in the cytoplasmic fraction of whole brain, while the dehydrogenase was enriched in the free mitochondria.     

Restriction digestion monitors facilitate plasmid construction and PCR cloning

Plasmid construction by "forced" or "directional" ligation of fragments digested with two different restriction enzymes is highly efficient, except when inhibited digestion of one site favors vector recircularization. Such failures often result because incomplete double digestion is undetected in vector polylinkers or at terminal cloning sites on a PCR fragment. To test cleavage efficiency indirectly, a "monitor" plasmid is added to the digest. In a suitable monitor, the two test sites are separated by enough DNA (approximately 20% of full length) to distinguish the double digest from the failed single digest. To make this applicable to combinations of 32 popular cloning enzymes, we constructed a set of 4 monitors (pDM1, pDM2, pDM3, and pDM4). Each contains three polylinkers separated by stuffer segments of approximately 1 kb. The 32 sites are distributed in the polylinkers such that at least one plasmid in the set is diagnostic for each enzyme pair. The set is designed to be extended to up to 81 sites. A linearized version of the monitor allows for the determination of which of the two enzymes has failed in an incomplete double digest and is also useful when the target DNA is close to the size of the pDM backbone. The plasmids also serve as versatile self-monitoring cloning vectors for any site combination.