ANALYSIS OF ALEXANDRIUM TAMARENSE (DINOPHYCEAE) GENES REVEALS THE COMPLEX EVOLUTIONARY HISTORY OF A MICROBIAL EUKARYOTE1

Microbial eukaryotes may extinguish much of their nuclear phylogenetic history due to endosymbiotic/horizontal gene transfer (E/HGT). We studied E/HGT in 32,110 contigs of expressed sequence tags (ESTs) from the dinoflagellate Alexandrium tamarense (Dinophyceae) using a conservative phylogenomic approach. The vast majority of predicted proteins (86.4%) in this alga are novel or dinoflagellate‐specific. We searched for putative homologs of these predicted proteins against a taxonomically broadly sampled protein database that includes all currently available data from algae and protists, and reconstructed a phylogeny from each of the putative homologous protein sets. Of the 2,523 resulting phylogenies, 14%–17% are potentially impacted by E/HGT involving both prokaryote and eukaryote lineages, with 2%–4% showing clear evidence of reticulate evolution. The complex evolutionary histories of the remaining proteins, many of which may also have been affected by E/HGT, cannot be interpreted using our approach with currently available gene data. We present empirical evidence of reticulate genome evolution that combined with inadequate or highly complex phylogenetic signal in many proteins may impede genome‐wide approaches to infer the tree of microbial eukaryotes.     

Organization of glycosaminoglycan sulfation in the biosynthesis of proteochondroitin sulfate and proteodermatan sulfate

Although the intermediates for sulfation of proteochondroitin and proteodermatan have been known for several decades, organizational aspects of this formation have not been clearly defined. Work in several laboratories, including our own, have indicated a pattern which strongly suggests that sulfation ordinarily takes place together with glycosaminoglycan polymerization in the same Golgi sites, and with close relationship to aspects of polymer elongation, polymer modification and polymer termination. the organization of sulfation together with polymerization may be a major factor controlling the location, type, and degree of sulfation, which in turn may direct specific functions of these proteoglycans.     

Food colorants metabolized by commensal bacteria promote colitis in mice with dysregulated expression of interleukin-23

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Influence of cisco (Coregonus artedi,Lesueur) on muskellunge (Esox masquinongy,Mitchill) mean length,population size structure,and maximum size in northern Wisconsin lakes

Population size structure and maximum size of managed sportfish populations are dictated by abiotic, biotic, ecosystem, and anthropogenic influences. In their native ranges of northern Wisconsin, muskellunge (Esox masquinongy) and cisco (Coregonus artedi) are co-adapted cool- and cold-water species where cisco presence may influence population size structure and maximum size of muskellunge. We tested whether muskellunge size structure indices (length-frequency distributions, proportional size distribution), mean length, and mean maximum length of muskellunge differed when cisco were present or absent in Ceded Territory of Wisconsin (CTWI) lakes during 2015–2018. Cisco presence had a positive influence on size structure and mean length of individual muskellunge within populations. In contrast, cisco presence had no influence on the mean maximum length of muskellunge observed in CTWI populations suggesting that other factors may be better predictors of this metric than cisco presence. In cisco lakes, mean muskellunge length was negatively correlated with mean cisco length suggesting that gape limitation may be a factor influencing population size structure and individual growth rates. Therefore, cisco populations with primarily large individuals may be unavailable to muskellunge as forage. Our results suggest that cisco are an important forage species for some aspects of muskellunge population ecology; however, other factors may also contribute to muskellunge population size structure and maximum size outcomes. As such, conservation of remaining cisco populations in Wisconsin is critical because they influence muskellunge population ecology in lakes where the species coexist. Future research is needed to better understand the interactions of cisco, abiotic and biotic factors, and anthropogenic influences on muskellunge growth dynamics.     

Dynamic rodent behavioral response to predation risk: implications for disease ecology

Oecologia - Prey modify their behavior in response to variation in predation risk, and such modifications can affect trophic processes such as disease transmission. However, variation in predation...     

Host range of Lepidelphax pistiae (Hemiptera: Delphacidae) and its potential impact on Pistia stratiotes L. (Araceae)

Pistia stratiotes L. (Araceae) is a floating aquatic plant that has become invasive in Florida. It is primarily controlled with herbicides, but two biocontrol agents have previously been released to assist in management of this species. A new potential biocontrol agent from Argentina, Lepidelphax pistiae Remes Lenicov (Hemiptera: Delphacidae), has been evaluated comprehensively for specificity after initial host range studies done in its native range indicated that it is likely specific to P. stratiotes. Host range studies indicated that this insect is specific to P. stratiotes, with no survival or reproduction occurring on any of the 42 other plant species tested. Impact studies indicated that this insect can significantly damage P. stratiotes at medium and high population densities, which were comparable to those seen in its native range. Lepidelphax pistiae is sufficiently specific enough to warrant release and has a high probability of aiding management of P. stratiotes populations in Florida.     

Are there biases in biopsy sampling? Potential drivers of sex ratio in projectile biopsy samples from two small delphinids

Molecular assays were used to determine the sex of 1,294 biopsied common dolphins (658 long‐beaked common dolphins, Delphinus capensis, and 636 short‐beaked common dolphins, D. delphis) in the Southern California Bight. Sex ratio differed substantially between the two species; females comprised 241 (36.6%) of D. capensis samples and 410 (64.5%) of D. delphis samples. All biopsies were taken either from a large research ship or from a small, rigid‐hull inflatable boat (RHIB) launched from the larger ship. When conducting replicate biopsy effort on the same schools from each vessel/platform (“Tandem Biopsy Sampling”), we found evidence that disproportionately more female D. capensis were biopsied from the RHIB than from the ship but the same was not true for D. delphis. We suspect that these results are driven by bowriding‐behavior differences between the two species. Biopsy duration, geographic location, school size, and Julian date were considered as potential covariates with sex ratio; geographic location was the only one to show strong evidence of correlation. This study also presents an alternative to the erroneous practice of comparing sex ratios to a theoretical assumption of parity (i.e., 50:50 sex ratio) when researchers avoid sampling animals paired with calves.