Platelet-derived growth factors (PDGFs) are important in many types of mesenchymal cell. Here we identify a new PDGF, PDGF-C, which binds to and activates the PDGF alpha-receptor. PDGF-C is activated by proteolysis and induces proliferation of fibroblasts when overexpressed in transgenic mice. In situ hybridization analysis in the murine embryonic kidney shows preferential expression of PDGF-C messenger RNA in the metanephric mesenchyme during epithelial conversion. Analysis of kidneys lacking the PDGF alpha-receptor shows selective loss of mesenchymal cells adjacent to sites of expression of PDGF-C mRNA; this is not found in kidneys from animals lacking PDGF-A or both PDGF-A and PDGF-B, indicating that PDGF-C may have a unique function.

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In plants, potassium (K ) homeostasis is tightly regulated and established against a concentration gradient to the environment. Despite the identification of Ca -regulated kinases as modulators of K channels, the immediate signaling and adaptation mechanisms of plants to low-K conditions are only partially understood. To assess the occurrence and role of Ca signals in Arabidopsis thaliana roots, we employed ratiometric analyses of Ca dynamics in plants expressing the Ca reporter YC3.6 in combination with patch-clamp analyses of root cells and two-electrode voltage clamp (TEVC) analyses in Xenopus laevis oocytes. K deficiency triggers two successive and distinct Ca signals in roots exhibiting spatial and temporal specificity. A transient primary Ca signature arose within 1 min in the postmeristematic stelar tissue of the elongation zone, while a secondary Ca response occurred after several hours as sustained Ca elevation in defined tissues of the elongation and root hair differentiation zones. Patch-clamp and TEVC analyses revealed Ca dependence of the activation of the K channel AKT1 by the CBL1-CIPK23 Ca sensor-kinase complex. Together, these findings identify a critical role of cell group-specific Ca signaling in low K responses and indicate an essential and direct role of Ca signals for AKT1 K channel activation in roots.

Nonaqueous solvent extraction is a promising technology for bitumen recovery from oil sands. In this study, influences of temperature, contact time, stirring rate, and solvent-to-oil sands ratio (V/M) on bitumen recovery, using a mixture solvent of n-heptane and toluene (V/V, 3:1), were investigated by L9 (34) orthogonal design. Under the orthogonal experiment conditions, the overall impacts of factors were ranked: V/M > stirring rate > contact time > temperature. Profiles of bitumen fractions (saturates, aromatics, resins, and asphaltenes) in the dissolved bitumen, suspended particles, and residual bitumen were investigated in single factor experiments. Asphaltenes have higher temperature sensitivity than other fractions. About 3–7 wt % bitumen particles coexisted with clay minerals (50–70 wt % of the suspended particles) suspended in the solution, most of which were composed of asphaltenes. Approximately 75–90 wt % of SAR fractions (saturates, aromatics, and resins) were dissolved in the composite solvent under the experimental conditions. The amount of residual fractions varied with conditions, and multistage extraction enhanced the bitumen recovery by up to 99%. The evaluation method for bitumen recovery based on dissolved fraction outperformed the methods based on the sum of dissolved and suspended particles. The conceptualization of the solvent extraction process in this study would improve the knowledge base for bitumen recovery mechanism and serve for future work on the engineering applications.

Two sika deer from a zoo in Florida were examined because of chronic hair loss and skin lesions. No common causes of alopecia were identified in either deer. One deer was treated with prednisone, but the condition worsened when the dosage was decreased. Both deer were euthanatized after several months because of continued disease. The predominant histologic lesion in skin specimens was granulomatous mural folliculitis. Serologic testing and sequencing of fragments produced with a consensus polymerase chain reaction assay indicated that both deer were infected with caprine herpesvirus-2, a newly recognized member of the malignant catarrhal fever group of viruses. Disease in these deer was substantially different from that typically seen following infection with ovine herpesvirus-2, the sheep-associated malignant catarrhal fever virus. Findings in these deer establish the pathogenicity of caprine herpesvirus-2 in sika deer and illustrate the ability of this group of complex herpesviruses to cause a wide variety of clinical abnormalities in diverse species.

The induction of vitellogenin in oviparous vertebrates has become the gold standard biomarker of exposure to estrogenic chemicals in the environment. This biomarker of estrogen exposure also has been used in arthropods, however, little is known of the factors that regulate the expression of vitellogenin in these organisms. We investigated changes in accumulation of mRNA products of the vitellogenin gene Vtg2 in daphnids (Daphnia magna) exposed to a diverse array of chemicals. We further evaluated the involvement of hormonal factors in the regulation of vitellogenin expression that may be targets of xenobiotic chemicals. Expression of the Vtg2 gene was highly responsive to exposure to various chemicals with an expression range spanning approximately four orders of magnitude. Chemicals causing the greatest induction were piperonyl butoxide, chlordane, 4-nonylphenol, cadmium, and chloroform. Among these, only 4-nonylphenol is recognized to be estrogenic. Exposure to several chemicals also suppressed Vtg2 mRNA levels, as much as 100-fold. Suppressive chemicals included cyproterone acetate, acetone, triclosan, and atrazine. Exposure to the estrogens diethylstilbestrol and bisphenol A had little effect on vitellogenin mRNA levels further substantiating that these genes are not induced by estrogen exposure. Exposure to the potent ecdysteroids 20-hydroxyecdysone and ponasterone A revealed that Vtg2 was subject to strong suppressive control by these hormones. Vtg2 mRNA levels were not significantly affected from exposure to several juvenoid hormones. Results indicate that ecdysteroids are suppressors of vitellogenin gene expression and that vitellogenin mRNA levels can be elevated or suppressed in daphnids by xenobiotics that elicit antiecdysteroidal or ecdysteroidal activity, respectively. Importantly, daphnid Vtg2 is not elevated in response to estrogenic activity.