Diel modulation of Hsp70 and Hsp60 in corals living in a shallow reef

Coral Reefs - In corals, different biological processes are associated with the daily variation of temperature and light, which in shallow reefs can vary widely and regularly reach extreme levels....     

CEP128 Localizes to the Subdistal Appendages of the Mother Centriole and Regulates TGF-β/BMP Signaling at the Primary Cilium

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Cytokine-Regulated Expression of Platelet-Derived Growth Factor Gene and Protein in Cultured Human Astrocytes

Abstract: To elucidate mechanisms regulating the production of platelet-derived growth factor (PDGF) in the CNS, we analyzed the influence of a panel of cytokines on PDGF mRNA and protein levels in astrocyte-enriched cultures from the human embryonic brain and spinal cord. Using a specific ELISA, PDGF AB protein was detected in serum-free astrocyte supernatants and its levels were significantly increased after treatment of the cultures with transforming growth factor-β₁ (TGF-β₁) or tumor necrosis factor-α (TNF-α); the largest increase was detected after combined treatment with the two cytokines. Interleukin-1β (IL-1β) by itself had little or no effect but synergized with TGF-β₁ in enhancing PDGF AB production. Supernatants from human astrocyte cultures stimulated the proliferation of rat oligodendrocyte progenitors, and most of the mitogenic activity could be accounted for by PDGF. By northern blot analysis, both PDGF A- and PDGF B-chain mRNAs were detected in untreated astrocytes. PDGF B-chain mRNA levels were increased by TGF-β₁, TNF-α, TNF-α/TGF-β₁, or IL-1β/TGF-β₁, whereas PDGF A-chain mRNA levels were not consistently affected by cytokine treatments. These in vitro data indicate that TGF-β₁, TNF-α, and IL-1β are able to stimulate astrocyte PDGF production. This cytokine network could play a role in CNS development and repair after injury or inflammation.     

Specific compositional patterns of synonymous positions in homologous mammalian genes

All 69 homologous coding sequences that are currently available in four mammalian orders were aligned and the synonymous (ie., third) positions of quartet (fourfold degenerate) codons were divided into three classes (that will be called conserved, intermediate, and variable), according to whether they show no change, one change, and more than one change, respectively. The three classes were analyzed in their compositional patterns. In the majority of GC-rich genes, the three classes of positions (but especially conserved positions) exhibited significantly different base compositions compared to expectations based on a random substitution process from the ancestral (consensus) sequence to the present-day (actual) sequences. Significant differences were rare in GC-poor genes.An analysis of the present results indicates that natural selection plays a role in the synonymous nucleotide substitution process, especially in GC-rich genes which represent the vast majority of mammalian genes.This paper is dedicated to the memory of Dr. Motoo Kimura (1924–1994)Correspondence to: Giorgio Bernardi     

Self-Esteem and Change in Body Mass Index over 3 Years in a Cohort of Adolescents

Self-esteem has been hypothesized to be lower in obese adolescents relative to their normal weight peers and to be an important factor in preventing or reversing obesity. The present study examined the relationship between obesity and self-esteem cross-sectionally and prospectively over three years in a cohort of 1278 adolescents in grades 7 to 9 at baseline. Cross-sectional analyses revealed an inverse association between physical appearance self-esteem and body mass index in both males and females. In females, body mass index was inversely associated with global self-esteem, close friendship, and behavioral conduct self-esteem. In males, body mass index was inversely associated with athletic and romantic appeal self-esteem. Prospectively, in females, physical appearance and social acceptance self-esteem at baseline were inversely related to body mass index three years later. Baseline self-esteem was unrelated prospectively to change in body mass index in males. All associations were modest in magnitude. These results suggest that in a middle class white sample of adolescents, self-esteem specific to physical appearance is modestly associated with body mass index. Low self-esteem does not appear to predict the development of obesity over time.     

Colonization of a novel depauperate habitat leads to trophic niche shifts in three desert lizard species

In a novel, depauperate ecosystem, colonizing species may experience changes in their trophic niche as a result of a new resource base and fewer competitors and predators. To examine trophic niche shifts of recent colonists, we focused on three ecologically and phylogenetically divergent lizard species that inhabit both the geologically distinctive depauperate habitat of White Sands and the surrounding Chihuahuan ‘dark soil’ desert in New Mexico. In White Sands the three species comprise the entire lizard community, whereas in the dark soils habitat, they constitute less than half of the lizard community abundance. As a result, we hypothesized that the three focal species would collectively represent a greater variety of trophic positions in the White Sands habitat than in the dark soils habitat. We hypothesized that the extent of shifts in each species’ trophic position would parallel diet and ecomorphology differences between habitats. To test these hypotheses, we combined analysis of lizard stomach contents with carbon and nitrogen stable isotopes in the context of previously published ecomorphology measurements. Stable isotope data indicated that as predicted, species were more different from one another in White Sands than in dark soils, suggesting community‐wide ecological release. Overall, all species were lower on the White Sands food chain; however, only one species decreased trophic level significantly, one increased trophic level variance, and one did not change significantly. Furthermore, stomach content data paralleled both stable isotope and ecomorphological data, showing different degrees of dietary overlap between habitats, depending on the species. That species’ differences in trophic ecology also correspond with ecomorphological differences suggests that these factors are either causally linked or collectively responding to similar ecological pressures, such as competition. By examining diet, trophic position, and ecomorphology of three colonist species, we demonstrate both species‐specific and community‐wide trophic differences in adjacent, but distinct habitats.