Fat Storage-inducing Transmembrane Protein 2 Is Required for Normal Fat Storage in Adipose Tissue

Triglycerides within the cytosol of cells are stored in a phylogenetically conserved organelle called the lipid droplet (LD). LDs can be formed at the endoplasmic reticulum, but mechanisms that regulate the formation of LDs are incompletely understood. Adipose tissue has a high capacity to form lipid droplets and store triglycerides. Fat storage-inducing transmembrane protein 2 (FITM2/FIT2) is highly expressed in adipocytes, and data indicate that FIT2 has an important role in the formation of LDs in cells, but whether FIT2 has a physiological role in triglyceride storage in adipose tissue remains unproven. Here we show that adipose-specific deficiency of FIT2 (AF2KO) in mice results in progressive lipodystrophy of white adipose depots and metabolic dysfunction. In contrast, interscapular brown adipose tissue of AF2KO mice accumulated few but large LDs without changes in cellular triglyceride levels. High fat feeding of AF2KO mice or AF2KO mice on the genetically obese ob/ob background accelerated the onset of lipodystrophy. At the cellular level, primary adipocyte precursors of white and brown adipose tissue differentiated in vitro produced fewer but larger LDs without changes in total cellular triglyceride or triglyceride biosynthesis. These data support the conclusion that FIT2 plays an essential, physiological role in fat storage in vivo.     

Structural analogues of ZAPA as GABAA agonists

Structural analogues of ZAPA, Z-3-[(aminoiminomethyl)thio]prop-2-enoic acid, an isothiouronium analogue of GABA, are potent GABA_A agonists as seen in the isolated guinea-pig ileum and in the facilitation of [³H]diazepam binding to rat brain membranes. Compounds with guanidino or amidine groups replacing the amino functionality of GABA were also found to be active. The highest activity was displayed by the isothiouronium salts in which the conformational flexibility of the molecule is restricted by a Z-substituted carbon–carbon double bond. A series of bis-isothiouronium compounds was prepared from aliphatic ,ω-bis-thioureas as mixtures of E and Z adducts. Maximum GABA_A agonist activity for this series was found with a C₆–C₈ carbon chain, and the results were consistent with an interaction at the GABA_A receptor with only one end of the molecule, rather than the more potent effect expected of a molecule bridging two active sites. GABA_A antagonist/partial agonist activity was observed on the guinea-pig isolated ileum for a number of different analogue types, with the most potent being bis-isothiouronium derivatives. None of the substituted derivatives of ZAPA was as active as ZAPA itself, and maximum GABA_A activity was found in the n-pentyl and n-hexyl analogues.     

Proliferating cell nuclear antigen (PCNA) as a proliferative marker during embryonic and adult zebrafish hematopoiesis

We investigated the expression of proliferative cell nuclear antigen (PCNA) in zebrafish to delineate the proliferative hematopoietic component during adult and embryonic hematopoiesis. Immunostaining for PCNA and enhanced green fluorescence protein (eGFP) was performed in wild-type and fli1-eGFP (endothelial marker) and gata1-eGFP (erythroid cell marker) transgenic fish. Expression of PCNA mRNA was examined in wild-type and chordin morphant embryos. In adult zebrafish kidney, the renal tubules are surrounded by endothelial cells and it is separated into hematopoietic and excretory compartments. PCNA was expressed in hematopoietic progenitor cells but not in mature neutrophils, eosinophils or erythroid cells. Some PCNA+ cells are scattered in the hematopoietic compartment of the kidney while others are closely associated with renal tubular cells. PCNA was also expressed in spermatogonial stem cells and intestine crypts, consistent with its role in cell proliferation and DNA synthesis. In embryos, PCNA is expressed in the brain, spinal cord and intermediate cell mass (ICM) at 24 h-post fertilization. In chordin morphants, PCNA is significantly upregulated in the expanded ICM. Therefore, PCNA can be used to mark cell proliferation in zebrafish hematopoietic tissues and to identify a population of progenitor cells whose significance would have to be further investigated.     

Setting and situation in migration from the Isle of Lewis*

This paper examines migration from the Isle of Lewis (Scotland). Mitchell's concepts of the social setting and the social situation of migration are employed: first, to demonstrate how the economic conditions of peripherality have created the factors, or social setting, promoting extensive out‐migration. Second, to demonstrate how the particular circumstances, or social situations, of individuals result in a wide range of types and patterns of migration. The historical development of the social setting and the effect of changes in it on migration are briefly examined. A number of career histories are used to illustrate the diversity of migrant responses to the setting. It is argued that this diversity is better understood if the concepts of type and pattern of migration are introduced into the analysis.     

Impact of temperature on Na2Sr(PO4)F:Eu3+ phosphor

In this article, we report the synthesis of Na₂Sr_1‐x(PO₄)F:Eu_x phosphor via a combustion method. The influence of different annealing temperatures on the photoluminescence properties was investigated. The phosphor was excited at both 254 and 393 nm. Na₂Sr_1‐x(PO₄)F:Eu_x³⁺ phosphors emit strong orange and red color at 593 and 612 nm, respectively, under both excitation wavelengths. Na₂Sr_1‐x(PO₄)F:Eu_x³⁺ phosphors annealed at 1050°C showed stronger emission intensity compared with 600, 900 and 1200°C. Moreover, Na₂Sr_1‐x(PO₄)F:Eu_x³⁺ phosphor was found to be more intense when compared with commercial Y₂O₃:Eu³⁺ phosphor. Copyright © 2013 John Wiley & Sons, Ltd.     

Selection of suitable housekeeping genes for expression analysis in glioblastoma using quantitative RT-PCR

Background  

Considering the broad variation in the expression of housekeeping genes among tissues and experimental situations, studies using quantitative RT-PCR require strict definition of adequate endogenous controls. For glioblastoma, the most common type of tumor in the central nervous system, there was no previous report regarding this issue.     

Genomic analysis of the relationship between gene expression variation and DNA polymorphism in Drosophila simulans

Background

Understanding how DNA sequence polymorphism relates to variation in gene expression is essential to connecting genotypic differences with phenotypic differences among individuals. Addressing this question requires linking population genomic data with gene expression variation.

Results

Using whole genome expression data and recent light shotgun genome sequencing of six Drosophila simulans genotypes, we assessed the relationship between expression variation in males and females and nucleotide polymorphism across thousands of loci. By examining sequence polymorphism in gene features, such as untranslated regions and introns, we find that genes showing greater variation in gene expression between genotypes also have higher levels of sequence polymorphism in many gene features. Accordingly, X-linked genes, which have lower sequence polymorphism levels than autosomal genes, also show less expression variation than autosomal genes. We also find that sex-specifically expressed genes show higher local levels of polymorphism and divergence than both sex-biased and unbiased genes, and that they appear to have simpler regulatory regions.

Conclusion

The gene-feature-based analyses and the X-to-autosome comparisons suggest that sequence polymorphism in cis-acting elements is an important determinant of expression variation. However, this relationship varies among the different categories of sex-biased expression, and trans factors might contribute more to male-specific gene expression than cis effects. Our analysis of sex-specific gene expression also shows that female-specific genes have been overlooked in analyses that only point to male-biased genes as having unusual patterns of evolution and that studies of sexually dimorphic traits need to recognize that the relationship between genetic and expression variation at these traits is different from the genome as a whole.     

Synthesis and biological evaluation of flavan-3-ol derivatives as positive modulators of GABAA receptors

We herein describe the synthesis and positive modulatory activities of a small library of flavan-3-ol derivatives on α₁β₂γ_2L GABA_A receptors. Structure–activity relationships of various substituents on the A, B and C rings were evaluated in a functional electrophysiological assay. A trans configuration and a 3-acetoxy moiety are essential for activity. Substitution of the B ring appears to be well tolerated, with substituents on the A ring playing a major role in determining activity.     

Guanidino Acids Act as ρ1 GABA<Subscript>C</Subscript> Receptor Antagonists

GABA_C receptors play a role in myopia, memory-related disorders and circadian rhythms signifying a need to develop potent and selective agents for this class of receptors. Guanidino analogs related to glycine, β-alanine and taurine were evaluated at human ρ₁GABA_C receptors expressed in Xenopus oocytes using 2-electrode voltage clamp methods. Of the 12 analogs tested, 8 analogs were active as antagonists and the remaining were inactive. (S)-2-Guanidinopropionic acid (IC₅₀ = 2.2 μM) and guanidinoacetic acid (IC₅₀ = 5.4 μM; K _B = 7.75 μM [pK _B = 5.11 ± 0.06]) were the most potent being competitive antagonists at this receptor. In contrast, the β-alanine and GABA guanidino analogs showed reduced activity, indicating the distance between the carboxyl carbon and terminal nitrogen of the guanidino group is critical for activity. Substituting the C2-position of guanidinoacetic acid with various alkyl groups reduced activity indicating that steric effects may impact on activity. The results of this study contribute to the structure–activity-relationship profile required in developing novel therapeutic agents.