Desmosomes are reduced in the mouse uterine luminal epithelium during the preimplantation period of pregnancy: a mechanism for facilitation of implantation

Dynamic regulation of intercellular junctions is an essential aspect of many developmental, reproductive, and physiological processes. We have shown that expression of the desmosomal protein desmoplakin decreases in the luminal uterine epithelium during the preimplantation period of pregnancy in mice. By the time of implantation (between Days 4.5 and 5 of pregnancy), desmoplakin protein can barely be detected by SDS-PAGE and Western blotting, and by immunocytochemistry, it is restricted to well-spaced, punctate dots at the apicolateral junction. Using confocal XZ series and electron microscope quantitation, both the density and distribution of desmosomes along the lateral cell surfaces of luminal epithelial cells were observed to change during early pregnancy. On Day 1 of pregnancy, desmosomes were found at high density in the apicolateral junctional complex, being present here in 79% of ultrathin sections examined, whereas on Day 5, the density was much reduced (present in only 18% of ultrathin sections examined). Desmosomes were found along the lateral surfaces, at or below the level of the nucleus, in 15% of ultrathin sections examined on Day 1 of pregnancy but in only 1% on Day 5. Desmoplakin mRNA declined during the first 4-5 days of pregnancy, along with the protein, suggesting that these changes are controlled at the level of mRNA. This study shows that desmosomes are regulated during early pregnancy, and we propose that a reduction in desmosome adhesion facilitates penetration of the luminal epithelium by trophoblast cells at implantation.     

The functional basis of granulocyte-macrophage colony stimulating factor, interleukin-3 and interleukin-5 receptor activation, basic and clinical implications

The cytokines granulocyte-macrophage colony stimulating factor, interleukin-3 and interleukin-5 have overlapping activities on cells expressing their receptors. This is explained by their sharing a receptor signal transduction subunit, beta c. This communal signaling subunit is also required for high affinity binding of all three cytokines. Therapeutic approaches attempting to interfere or modulate haemopoietic cells using cytokines or their analogues can in some instances be limited due to functional redundancy amongst cytokines using shared receptor signaling subunits. Therefore, a better approach would be to develop therapeutics against the shared subunit. Studies examining the GM-CSF, IL-3 and IL-5 receptors have identified the key events leading to functional receptor activation. With this knowledge, it is now possible to identify new targets for the development of a new class of antagonist that blocks the biological activity of all the cytokines utilizing beta c. This approach may be extended to other receptor systems such as IL-4 and IL-13 where receptor activation is dependent on a common signaling and binding subunit.     

Genetic structure and gene flow among European corn borer populations from the Great Plains to the Appalachians of North America

• 1 Earlier population genetic spatial analysis of European corn borer Ostrinia nubilalis (Hübner) indicated no genetic differentiation even between locations separated by 720 km. This result suggests either high dispersal resulting in high gene flow or that populations are not in migration–drift equilibrium subsequent to their invasion of the central U.S.A. in the 1940s.
• 2 To discriminate among these two possibilities, samples were collected at 12 locations in eight states from New York to Colorado, a geographic scale that is three‐fold greater than previously tested. Eight microsatellite markers were employed to estimate genetic differentiation and gene flow among these populations, and to test for isolation‐by‐distance.
• 3 Although pairwise F_ST estimates were very low, there was a significant isolation‐by‐distance relationship.
• 4 Wright's neighbourhood area (i.e. the surface area covered by a panmictic group of individuals within a larger continuous distribution) was calculated as 433 km², and the radius indicates that approximately 13% of O. nubilalis adults disperse a net distance >12 km per generation from their natal source.
• 5 Analyses indicated significant differentiation between the north‐eastern region (New York and Pennsylvania) and the region combining sample locations from Ohio to Colorado, suggesting the potential for isolation of populations by topographic barriers in the Northeast.
• 6 Taken together, the results suggest that O. nubilalis exhibits substantial gene flow over long distances and that the lack of genetic differentiation between populations across hundreds of kilometres is not simply a result of migration–drift disequilibrium arising from the recent range expansion.

     

Shorebird Abundance Estimates in Interior Alaska

Interior Alaska, USA, is the least-studied region in Alaska for breeding shorebirds because of challenging accessibility and expectations of low densities and abundances. We estimated lowland and upland shorebird population sizes on 370,420 ha of military lands in interior Alaska boreal forest from May–July 2016 and 2017. We modified the Program for Regional and International Shorebird Monitoring (PRISM) protocol used elsewhere in Alaska and incorporated a probability-based sampling design and dependent double-observer methods. We pooled all lowland shorebird and all upland shorebird observations and estimated abundance using Huggins closed captures models in Program MARK. Estimated abundances of all lowland and upland shorebirds were 42,239 ± 13,431 (SE) and 3,523 ± 494, respectively. The survey area is important for shorebirds in Alaska. We estimate that military lands in interior Alaska support 45,762 ± 13,925 shorebirds, including 7 species of conservation concern. Higher abundance of lowland shorebirds was best explained by lower elevation, lower percent scrub canopy, and higher percent water on plots. Higher abundance of upland shorebirds was best explained by higher elevation and increased distance to wetland. Our modified Arctic PRISM protocol was effective for surveys in the boreal forest and we recommend continued use of method modifications for future shorebird surveys in boreal forests. Identifying baseline abundances of shorebirds using interior Alaska is an important step in monitoring distributional shifts and potential future population declines. © 2020 The Authors. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society.     

Antimicrobial resistance and virulence determinants in European Salmonella genomic island 1-positive Salmonella enterica isolates from different origins

Salmonella genomic island 1 (SGI1) contains a multidrug resistance region conferring the ampicillin-chloramphenicol-streptomycin-sulfamethoxazole-tetracycline resistance phenotype encoded by bla(PSE-1), floR, aadA2, sul1, and tet(G). Its increasing spread via interbacterial transfer and the emergence of new variants are important public health concerns. We investigated the molecular properties of SGI1-carrying Salmonella enterica serovars selected from a European strain collection. A total of 38 strains belonging to S. enterica serovar Agona, S. enterica serovar Albany, S. enterica serovar Derby, S. enterica serovar Kentucky, S. enterica serovar Newport, S. enterica serovar Paratyphi B dT+, and S. enterica serovar Typhimurium, isolated between 2002 and 2006 in eight European countries from humans, animals, and food, were subjected to antimicrobial susceptibility testing, molecular typing methods (XbaI pulsed-field gel electrophoresis [PFGE], plasmid analysis, and multilocus variable-number tandem-repeat analysis [MLVA]), as well as detection of resistance and virulence determinants (PCR/sequencing and DNA microarray analysis). Typing experiments revealed wide heterogeneity inside the strain collection and even within serovars. PFGE analysis distinguished a total of 26 different patterns. In contrast, the characterization of the phenotypic and genotypic antimicrobial resistance revealed serovar-specific features. Apart from the classical SGI1 organization found in 61% of the strains, seven different variants were identified with antimicrobial resistance properties associated with SGI1-A (S. Derby), SGI1-C (S. Derby), SGI1-F (S. Albany), SGI1-L (S. Newport), SGI1-K (S. Kentucky), SGI1-M (S. Typhimurium), and, eventually, a novel variant similar to SGI1-C with additional gentamicin resistance encoded by aadB. Only minor serovar-specific differences among virulence patterns were detected. In conclusion, the SGI1 carriers exhibited pathogenetic backgrounds comparable to the ones published for susceptible isolates. However, because of their multidrug resistance, they may be more relevant in clinical settings.     

Rapid synthesis of VX-745: p38 MAP kinase inhibition in Werner syndrome cells

The p38 mitogen-activated protein kinase inhibitor VX-745 is prepared rapidly and efficiently in a four-step sequence using a combination of conductive heating and microwave-mediated steps. Its inhibitory activity was confirmed in hTERT immortalized HCA2 and WS dermal fibroblasts at 0.5-1.0 microM concentration by ELISA and immunoblot assay, and displays excellent kinase selectivity over the related stress-activated kinase JNK.     

Testing for shared biogeographic history in the lower Central American freshwater fish assemblage using comparative phylogeography: concerted,independent, or multiple evolutionary responses?

A central goal of comparative phylogeography is determining whether codistributed species experienced (1) concerted evolutionary responses to past geological and climatic events, indicated by congruent spatial and temporal patterns (“concerted‐response hypothesis”); (2) independent responses, indicated by spatial incongruence (“independent‐response hypothesis”); or (3) multiple responses (“multiple‐response hypothesis”), indicated by spatial congruence but temporal incongruence (“pseudocongruence”) or spatial and temporal incongruence (“pseudoincongruence”). We tested these competing hypotheses using DNA sequence data from three livebearing fish species codistributed in the Nicaraguan depression of Central America (Alfaro cultratus, Poecilia gillii, and Xenophallus umbratilis) that we predicted might display congruent responses due to co‐occurrence in identical freshwater drainages. Spatial analyses recovered different subdivisions of genetic structure for each species, despite shared finer‐scale breaks in northwestern Costa Rica (also supported by phylogenetic results). Isolation‐with‐migration models estimated incongruent timelines of among‐region divergences, with A. cultratus and Xenophallus populations diverging over Miocene–mid‐Pleistocene while P. gillii populations diverged over mid‐late Pleistocene. Approximate Bayesian computation also lent substantial support to multiple discrete divergences over a model of simultaneous divergence across shared spatial breaks (e.g., Bayes factor [B₁₀] = 4.303 for Ψ [no. of divergences] > 1 vs. Ψ = 1). Thus, the data support phylogeographic pseudoincongruence consistent with the multiple‐response hypothesis. Model comparisons also indicated incongruence in historical demography, for example, support for intraspecific late Pleistocene population growth was unique to P. gillii, despite evidence for finer‐scale population expansions in the other taxa. Empirical tests for phylogeographic congruence indicate that multiple evolutionary responses to historical events have shaped the population structure of freshwater species codistributed within the complex landscapes in/around the Nicaraguan depression. Recent community assembly through different routes (i.e., different past distributions or colonization routes), and intrinsic ecological differences among species, has likely contributed to the unique phylogeographical patterns displayed by these Neotropical fishes.     

Cytokine-augmented culture of haematopoietic progenitor cells in a novel three-dimensional cell growth matrix

Studies aimed at the in vitro expansion of haematopoietic progenitor cells (HPCs) have suffered from the conflict of increasing cell numbers while maintaining long-term repopulating ability. We have developed a long-term bone marrow bioreactor culture system resembling the marrow-microenvironment that cultures HPCs in an inert, three-dimensional, porous biomatrix termed Cellfoam. Previous studies have shown that the short-term culture of CD34(+)cells in Cellfoam improved the maintenance and multipotency of haematopoietic stem cells compared to cells cultured on plastic dishes. In this study, we examined the effects of low concentrations of cytokines including stem cell factor (SCF), IL-3, and Flk-2/Flt-3 ligand, on the maintenance, preservation and multipotency of CD34(+) cells cultured for 3 or 6 weeks in Cellfoam. Analysis of cell yields using flow cytometry showed that in SCF and Flk-2/Flt-3 ligand-supplemented cultures as well as cytokine-free cultures, a higher number of CD45(+)34(+) and CD45(+)34(+)38(-) cells is observed in Cellfoam cultures as compared to plastic cultures. The function of cultured cells was evaluated in colony-forming assays. The data demonstrate that Cellfoam cultures supplemented with SCF and Flk-2/Flt-3 ligand resulted in a higher output of colony activity compared to plastic cultures. Analysis of CAFC (29 days) activity also demonstrated that primitive progenitors were maintained to a greater extent in Cellfoam cultures containing either no cytokines or low concentrations of early-acting cytokines. These data suggest that culture of HPCs in three-dimensional bioreactors such as Cellfoam for extended periods may benefit from the addition of low levels of early-acting cytokines, including SCF and Flk-2/Flt-3 ligand, resulting in high yields of cells that are enriched for multipotent haematopoietic progenitors. These findings demonstrate that a three-dimensional matrix promotes the survival of primitive HPCs in culture and may modulate the in vitro effects of cytokines.     

Molecular phylogeny and phylogeography of the Australian freshwater fish genus Galaxiella, with an emphasis on dwarf galaxias (G. pusilla)

The freshwater fauna of Southern Australia is primarily restricted to the southwestern and southeastern corners of the continent, and is separated by a large, arid region that is inhospitable to this biota. This geographic phenomenon has attracted considerable interest from biogeographers looking to explain evolutionary diversification in this region. Here, we employed phylogenetic and phylogeographic approaches to evaluate the effect of this barrier on a group of four galaxiid fish species (Galaxiella) endemic to temperate Southern Australia. We also tested if continental shelf width has influenced connectivity among populations during low sea levels when rivers, now isolated, could have been connected. We addressed these questions by sampling each species across its range using multiple molecular markers (mitochondrial cytochrome b sequences, nuclear S7 intron sequences, and 49 allozyme loci). These data also allowed us to assess species boundaries, to refine phylogenetic affinities, and to estimate species ages. Interestingly, we found compelling evidence for cryptic species in G. pusilla, manifesting as allopatric eastern and western taxa. Our combined phylogeny and dating analysis point to an origin for the genus dating to the early Cenozoic, with three of the four species originating during the Oligocene-Miocene. Each Galaxiella species showed high levels of genetic divergences between all but the most proximate populations. Despite extensive drainage connections during recent low sea levels in southeastern Australia, populations of both species within G. pusilla maintained high levels of genetic structure. All populations experienced Late Pleistocene-Holocene population growth, possibly in response to the relaxation of arid conditions after the last glacial maximum. High levels of genetic divergence and the discovery of new cryptic species have important implications for the conservation of this already threatened group of freshwater species.