Independent effects of ocean warming versus acidification on the growth,survivorship and physiology of two Acropora corals

Coral Reefs - Climate change is the greatest threat to coral reef ecosystems. Importantly, gradual changes in seawater chemistry compounds upon increasing temperatures leading to declines in...     

Systems analysis of immune responses to attenuated P. falciparum malaria sporozoite vaccination reveals excessive inflammatory signatures correlating with impaired immunity

Immunization with radiation-attenuated sporozoites (RAS) can confer sterilizing protection against malaria, although the mechanisms behind this protection are incompletely understood. We performed a systems biology analysis of samples from the Immunization by Mosquito with Radiation Attenuated Sporozoites (IMRAS) trial, which comprised P. falciparum RAS-immunized (PfRAS), malaria-naive participants whose protection from malaria infection was subsequently assessed by controlled human malaria infection (CHMI). Blood samples collected after initial PfRAS immunization were analyzed to compare immune responses between protected and non-protected volunteers leveraging integrative analysis of whole blood RNA-seq, high parameter flow cytometry, and single cell CITEseq of PBMCs. This analysis revealed differences in early innate immune responses indicating divergent paths associated with protection. In particular, elevated levels of inflammatory responses early after the initial immunization were detrimental for the development of protective adaptive immunity. Specifically, non-classical monocytes and early type I interferon responses induced within 1 day of PfRAS vaccination correlated with impaired immunity. Non-protected individuals also showed an increase in Th2 polarized T cell responses whereas we observed a trend towards increased Th1 and T-bet+ CD8 T cell responses in protected individuals. Temporal differences in genes associated with natural killer cells suggest an important role in immune regulation by these cells. These findings give insight into the immune responses that confer protection against malaria and may guide further malaria vaccine development.Trial registration: ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01994525","term_id":"NCT01994525"}}NCT01994525.     

A GrpE mutant containing the NH(2)-terminal "tail" region is able to displace bound polypeptide substrate from DnaK

A key feature to the dimeric structure for the GrpE heat shock protein is the pair of long helices at the NH(2)-terminal end followed by a presumable extended segment of about 30 amino acids from each monomer. We have constructed a GrpE deletion mutant protein that contains only the unique tail portion (GrpE1-89) and another that is missing this region (GrpE88-197). Circular dichroism analysis shows that the GrpE1-89 mutant still contains one-third percent alpha-helical secondary structure. Using an assay that measures bound peptide to DnaK we show that the GrpE1-89 is able to lower the amount of bound peptide, whereas GrpE88-197 has no effect. Additionally, when the same peptide binding assay is carried out with the COOH-terminal domain of DnaK, the full-length GrpE and the two GrpE deletion mutants show little to no effect on peptide release. Furthermore, the GrpE88-197 mutant is able to enhance the off-rate of nucleotide from DnaK and the 1-89 mutant has no effect on the nucleotide release. Similar results of nucleotide release are observed with the NH(2)-terminal ATPase domain mutant of DnaK. The results presented show directly that there is interaction between the GrpE protein's "tail" region and the substrate COOH-terminal peptide binding domain of DnaK, although the effect is only fully manifest with an intact full-length DnaK molecule.     

Lack of causal relationship between clusterin expression and photoreceptor apoptosis in light-induced retinal degeneration

Induction of apoptosis in the retina leads to cellular death by molecular mechanisms that are not well understood. Clusterin expression is increased in tissues undergoing apoptosis, including retinal neurodegenerative states, but the causal relationships remain to be clarified. To gain insight into clusterin's role in photoreceptor apoptosis, the cellular distribution of clusterin mRNA was compared with the pattern of apoptotic nuclear labelling in a rat model of light-induced retinal degeneration. In control retinal sections, clusterin mRNA was localized to the retinal pigment epithelium cells, photoreceptor inner segments, inner nuclear layer, and ganglion cell layer. Clusterin expression decreased in photoreceptors and retinal pigment epithelium cells, which progressively degenerated, and increased in preserved inner nuclear layer, in proportion to the duration of light exposure in both cyclic light- and dark-reared animals. These results suggest that clusterin is not causally involved in apoptotic mechanisms of photoreceptor death, but may relate to cytoprotective functions.     

A short loop on the ALK-2 and ALK-4 activin receptors regulates signaling specificity but cannot account for all their effects on early Xenopus development

Activin, a member of the transforming growth factor beta (TGF-beta) superfamily, signals through a heteromeric complex of type I and type II serine-threonine kinase receptors. The two activin type I receptors previously identified, ALK-2 (ActR-I) and ALK-4 (ActR-IB), have distinct effects on gene expression, differentiation and morphogenesis in the Xenopus animal cap assay. ALK-4 reproduces the effects of activin treatment including the dose-dependent induction of progressively more dorso-anterior mesodermal and endodermal markers, whereas ALK-2 induces only ventral mesodermal markers and counteracts the effects of ALK-4. To identify regions of the receptors that determine signaling specificity we have generated chimeras of the constitutively active ALK-2 and ALK-4 receptors (termed ALK-2* and ALK-4*). The effects of these chimeric receptors on gene expression and morphogenetic movements implicate the loop between kinase subdomains IV and V in mediating the strong dorsal gene-inducing properties of ALK-4*; when the seven amino acids comprising this loop are transferred from ALK-4* to ALK-2*, the resulting chimeric receptor is capable of inducing the expression of dorsal-specific genes. In contrast, when the equivalent region of ALK-2* is transferred to the ALK-4* backbone it cannot effectively counteract the dorsalizing effects of ALK-4*, suggesting that other regions of type I receptors are also involved in determining signal specificity.     

Protein kinase C-mediated phosphorylation of the leukemia-associated HOXA9 protein impairs its DNA binding ability and induces myeloid differentiation

HOXA9 expression is a common feature of acute myeloid leukemia, and high-level expression is correlated with poor prognosis. Moreover, HOXA9 overexpression immortalizes murine marrow progenitors that are arrested at a promyelocytic stage of differentiation when cultured and causes leukemia in recipient mice following transplantation of HOXA9 expressing bone marrow. The molecular mechanisms underlying the physiologic functions and transforming properties of HOXA9 are poorly understood. This study demonstrates that HOXA9 is phosphorylated by protein kinase C (PKC) and casein kinase II and that PKC mediates phosphorylation of purified HOXA9 on S204 as well as on T205, within a highly conserved consensus sequence, in the N-terminal region of the homeodomain. S204 in the endogenous HOXA9 protein was phosphorylated in PLB985 myeloid cells, as well as in HOXA9-immortalized murine marrow cells. This phosphorylation was enhanced by phorbol ester, a known inducer of PKC, and was inhibited by a specific PKC inhibitor. PKC-mediated phosphorylation of S204 decreased HOXA9 DNA binding affinity in vitro and the ability of the endogenous HOXA9 to form cooperative DNA binding complexes with PBX. PKC inhibition significantly reduced the phorbol-ester induced differentiation of the PLB985 hematopoietic cell line as well as HOXA9-immortalized murine bone marrow cells. These data suggest that phorbol ester-induced myeloid differentiation is in part due to PKC-mediated phosphorylation of HOXA9, which decreases the DNA binding of the homeoprotein.     

Does the ‘Old Bag’ Make a Good ‘Wind Bag’?: Comparison of Four Fabrics Commonly Used as Exclusion Bags in Studies of Pollination and Reproductive Biology

BACKGROUND AND AIMS: Fabrics used in pollination bags may exclude pollen carried by biotic vectors, but have varying degrees of permeability to wind-borne pollen. The permeability of bags to wind-borne pollen may have important consequences in studies of pollination and reproductive biology. The permeability of four fabrics commonly used in the construction of pollination bags was examined. METHODS: Deposition of wind-borne pollen on horizontally and vertically oriented microscope slides was assessed on slides enclosed in pollination bags, as well as on control slides. KEY RESULTS: It was found that the permeability of fabrics to wind-borne pollen, as measured by deposition on both horizontally and vertically oriented slides, decreased with pore size. However, deposition on horizontal slides was always greater than on vertical slides for a given fabric; this could manifest itself as differential success of pollination of flowers in bags-dependent on flower orientation. CONCLUSIONS: Obviously, bags with mesh size smaller than most pollen grains are impermeable to pollen. However, material for such bags is very expensive. In addition, it was also observed that bags with even moderately small pore size, such as pores (approx. 200 microm) in twisted fibre cotton muslin, offered highly significant barriers to passage of wind-borne pollen. Such bags are sufficiently effective in most large-sample-size reproductive biology studies.     

Effect of soluble epoxide hydrolase inhibition on epoxyeicosatrienoic acid metabolism in human blood vessels

We investigated the effects of soluble epoxide hydrolase (sEH) inhibition on epoxyeicosatrienoic acid (EET) metabolism in intact human blood vessels, including the human saphenous vein (HSV), coronary artery (HCA), and aorta (HA). When HSV segments were perfused with 2 micromol/l 14,15-[3H]EET for 4 h, >60% of radioactivity in the perfusion medium was converted to 14,15-dihydroxyeicosatrienoic acid (DHET). Similar results were obtained with endothelium-denuded vessels. 14,15-DHET was released from both the luminal and adventitial surfaces of the HSV. When HSVs were incubated with 14,15-[3H]EET under static (no flow) conditions, formation of 14,15-DHET was detected within 15 min and was inhibited by the selective sEH inhibitors N,N'-dicyclohexyl urea and N-cyclohexyl-N'-dodecanoic acid urea (CUDA). Similarly, CUDA inhibited the conversion of 11,12-[3H]EET to 11,12-DHET by the HSV. sEH inhibition enhanced the uptake of 14,15-[3H]EET and facilitated the formation of 10,11-epoxy-16:2, a beta-oxidation product. The HCA and HA converted 14,15-[3H]EET to DHET, and this also was inhibited by CUDA. These findings in intact human blood vessels indicate that conversion to DHET is the predominant pathway for 11,12- and 14,15-EET metabolism and that sEH inhibition can modulate EET metabolism in vascular tissue.     

Discovery of a potent, selective and orally active canine COX-2 inhibitor, 2-(3-difluoromethyl-5-phenyl-pyrazol-1-yl)-5-methanesulfonyl-pyridine

Structure-activity relationship (SAR) studies of 2-[3-di(and tri)fluoromethyl-5-arylpyrazol-1-yl]-5-methanesulfonylpyridine derivatives for canine COX enzymes are described. This led to the identification of 12a as a lead candidate for further progression. The in vitro and in vivo activity of 12a for the canine COX-2 enzyme as well as its in vivo efficacy and pharmacokinetic properties in dog are highlighted.