Mouse conceptuses have a limited capacity to elevate the mRNA level of cellular retinoid binding proteins in response to teratogenic doses of retinoic acid.

In these studies, we wished to determine the effect of teratogenic doses of retinoic acid on the expression of cellular retinoic acid binding protein I (CRABP-I) mRNA, cellular retinoic acid binding protein II (CRABP-II) mRNA, cellular retinol binding protein I (CRBP-I) mRNA, and cellular retinol binding protein II (CRBP-II) mRNA in mouse conceptuses. Levels of CRABP-II mRNA and CRBP-I mRNA were modestly elevated (2.5-fold and 1.5-fold, respectively) in 9-day gestation conceptuses following treatment of dams with 100 mg/kg b.w. of retinoic acid. These levels were elevated by 6 hr following treatment and remained elevated until 48 and 24 hr, respectively. Two other retinoids, etretinate and retinoyl beta-glucuronide, also moderately elevated CRABP-II mRNA and CRBP-I mRNA levels in conceptuses. In contrast, the levels of CRABP-I mRNA in the conceptuses remained unaffected by treatment with any of these three retinoids. These results demonstrate that conceptuses have a limited capacity to elevate the cellular retinoid binding proteins mRNA levels and presumably the synthesis of their respective proteins in response to high, teratogenic doses of retinoic acid. As a result, an excess of free retinoic acid becomes available to the nuclear retinoic acid receptors, which may lead to inappropriate gene expression and eventual maldevelopment.     

An evolutionary model for the insect vitellins

Insects can be divided into three groups based on the sizes of the polypeptide constituents of their vitellogenins and vitellins. In order to determine the relationships between these groups, antisera to the vitellins of seven insects from six taxonomic orders were used to assess immunological cross-reactivity. Antigenic relatedness was observed only between vitellins from species within the same family. Amino acid compositional data for vitellins from nine species were used to assess homology by difference matrices. The SΔQ values were similar for both intra-order and inter-order comparisons and strongly suggested relatedness. The SΔ_n comparisons supported the immunological data that indicated that the vitellins were evolving rapidly. For most insect vitellins there are two distinct size classes of polypeptides that seem to be derived from a single asymmetric proteolytic cleavage of a precursor. We propose a model that suggests that the different size polypeptides represent distinct domains and that in the evolution of the vitellogenin genes of the Diptera and Hymenoptera there has been domain elimination.     

Glycoproteins of herpes simplex virus type 2 as defined by monoclonal antibodies.

We used monoclonal antibodies reacting with glycoproteins specified by herpes simplex virus type 2 (HSV-2) to characterize the individual antigens in terms of structure, processing, and kinetics of synthesis in BHK or Vero infected cells. Our results provided a direct demonstration of the structural identity of the gA and gB proteins of HSV-2 as well as confirmation of the existence of type-specific and type-common domains within the gD molecule. They also show that, with the exception of gC, processing of the viral glycoproteins differs to some extent in Vero and BHK infected cells, possibly as a result of different efficiency of glycosylation or different processing of underglycosylated and unglycosylated products in the two cell types. Finally, we showed that individual HSV-2 glycoproteins are synthesized at greatly different times during the infectious cycle, possibly in response to their different roles in virus replication and assembly.     

Characterization of polypeptides immunoprecipitable from Pichinde virus-infected BHK-21 cells

Using hamster anti-Pichinde virus serum, we immunoprecipitated polypeptides from BHK-21 cells infected with Pichinde virus. Seven immunoprecipitable polypeptides exhibited a time- and multiplicity of infection-dependent appearance when the cultures were pulse-labeled with L-[35S]methionine for 1 h. The predominant polypeptide was a nucleoprotein (NP) of 64,000 daltons. Components of 48,000, 38,000, and 28,000 daltons, when analyzed by two-dimensional tryptic peptide mapping, were found to be derived from NP. After a 3-h chase period, polypeptides of 17,000, 16,500, and 14,000 daltons were evident, and peptide mapping revealed that these three polypeptides were also related to NP. During a series of pulse-chase experiments, a 79,000-dalton glycoprotein (GPC) was cleaved to glycoproteins of 52,000 and 36,000 daltons. Radiolabel in a polypeptide of approximately 200,000 daltons (L) did not chase into smaller cleavage products. L, GPC, and NP were found to be unique by two-dimensional tryptic peptide mapping. Comparison of polypeptides immunoprecipitated from infected cells with structural components of purified virus revealed that L protein was evident in both. This is the first report of a high-molecular-weight polypeptide in Pichinde virus particles and infected cells.     

Using RAD‐seq to develop sex‐linked markers in a haplodiplontic alga

For many taxa, including isomorphic haplodiplontic macroalgae, determining sex and ploidy is challenging, thereby limiting the scope of some population demographic and genetic studies. Here, we used double‐digest restriction site‐associated DNA sequencing (ddRAD‐seq) to identify sex‐linked molecular markers in the widespread red alga Agarophyton vermiculophyllum. In the ddRAD‐seq library, we included 10 female gametophytes, 10 male gametophytes, and 16 tetrasporophytes from one native and one non‐native site (N = 40 gametophytes and N = 32 tetrasporophytes total). We identified seven putatively female‐linked and 19 putatively male‐linked sequences. Four female‐ and eight male‐linked markers amplified in all three life cycle stages. Using one female‐ and one male‐linked marker that were sex‐specific, we developed a duplex PCR and tested the efficacy of this assay on a subset of thalli sampled at two sites in the non‐native range. We confirmed ploidy based on the visual observation of reproductive structures and previous microsatellite genotyping at 10 polymorphic loci. For 32 vegetative thalli, we were able to assign sex and confirm ploidy in these previously genotyped thalli. These markers will be integral to ongoing studies of A. vermiculophyllum invasion. We discuss the utility of RAD‐seq over other approaches previously used, such as RAPDs (random amplified polymorphic DNA), for future work designing sex‐linked markers in other haplodiplontic macroalgae for which genomes are lacking.     

Stream Water Chemistry in Mixed-Conifer Headwater Basins: Role of Water Sources,Seasonality, Watershed Characteristics,and Disturbances

Ecosystems - Understanding the transport of dissolved organic carbon (DOC) and nitrogen (N) as water flows through headwater basins is important for predicting downstream water quality. With...