CD147 and AGR2 expression promote cellular proliferation and metastasis of head and neck squamous cell carcinoma

The signaling pathways facilitating metastasis of head and neck squamous cell carcinoma (HNSCC) cells are not fully understood. CD147 is a transmembrane glycoprotein known to induce cell migration and invasion. AGR2 is a secreted peptide also known to promote cell metastasis. Here we describe their importance in the migration and invasion of HNSCC cells (FADU and OSC-19) in vitro and in vivo. In vitro, knockdown of CD147 or AGR2 decreased cellular proliferation, migration and invasion. In vivo, knockdown of CD147 or AGR2 expression decreased primary tumor growth as well as regional and distant metastasis.     

Detecting successional changes in tropical forest structure using GatorEye drone-borne lidar

Drone-based remote sensing is a promising new technology that combines the benefits of ground-based and satellite-derived forest monitoring by collecting fine-scale data over relatively large areas in a cost-effective manner. Here, we explore the potential of the GatorEye drone-lidar system to monitor tropical forest succession by canopy structural attributes including canopy height, spatial heterogeneity, gap fraction, leaf area density (LAD) vertical distribution, canopy Shannon index (an index of LAD), leaf area index (LAI), and understory LAI. We focus on these variables’ relationship to aboveground biomass (AGB) stocks and species diversity. In the Caribbean lowlands of northeastern Costa Rica, we analyze nine tropical forests stands (seven second-growth and two old-growth). Stands were relatively homogenous in terms of canopy height and spatial heterogeneity, but not in their gap fraction. Neither species density nor tree community Shannon diversity index was significantly correlated with the canopy Shannon index. Canopy height, LAI, and AGB did not show a clear pattern as a function of forest age. However, gap fraction and spatial heterogeneity increased with forest age, whereas understory LAI decreased with forest age. Canopy height was strongly correlated with AGB. The heterogeneous mosaic created by successional forest patches across human-managed tropical landscapes can now be better characterized. Drone-lidar systems offer the opportunity to improve assessment of forest recovery and develop general mechanistic carbon sequestration models that can be rapidly deployed to specific sites, an essential step for monitoring progress within the UN Decade on Ecosystem Restoration.     

STUDIES IN THE DYNAMICS OF HISTOGENESIS : I. TENSION OF DIFFERENTIAL GROWTH AS A STIMULUS TO MYOGENESIS.

1. The region of most active mitosis per mm. of cross-section in the intestine is the entodermal epithelial tube. The mitotic figures primarily follow the path of a right-handed helix. In one of the twenty embryos the mitotic figures describe the path of a right-handed helix. 2. The region of least active or relatively passive growth per mm. of cross-section is the mesenchyme, derived from the splanchnic mesoderm surrounding the epithelial tube. 3. The rapid expansion, due to epithelial growth in a rotating spiral manner, of the intestinal lumen is greater than the activity manifest in the surrounding mesenchyme. This causes a pressure in the latter resulting in a flattening and elongation of the mesenchymal cells. The successive changes in shape of these cells through the spherical, ellipsoidal, and spindle cellular phases are seen. The mesenchymal wall decreases in thickness, due to tension caused by epithelial tubular dilation. 4. The rotating spiral growth of the epithelial cells causes the formation of a series of mesenchymal cellular and fibrillar concentric rings due to the centripetal force of the former. 5. The circular, smooth muscle cells are differentiated in the outer, more condensed margins of the ring. At these points the developing tensional stresses are greater than within the ring. 6. The inner circular smooth muscle coat is the first one differentiated and is incident to the rapid growth of the epithelial tube in diameter. The former soon tends to restrict the growth of the epithelial tube in diameter. The tube, pursuing the lines of least resistance, grows in length. During the period of rapid growth in length the outer longitudinal muscle coat is in the process of formation. 7. The tensional stresses to which the elongated strained mesenchymal cells are subjected appear to be a dynamic stimulus to smooth muscle differentiation. 8. From this study of a closely graded and progressive series of sections of intestinal development, the conclusion is drawn that muscle tissue is not self-differentiating, in the strict sense of the term, but that the tension of differential growth acts as the stimulus to smooth muscle differentiation.     

Geographic variation in the plumage coloration of willow flycatchers Empidonax traillii

The ability to identify distinct taxonomic groups of birds (species, subspecies, geographic races) can advance ecological research efforts by determining connectivity between the non‐breeding and breeding grounds for migrant species, identifying the origin of migrants, and helping to refine boundaries between subspecies or geographic races. Multiple methods are available to identify taxonomic groups (e.g., morphology, genetics), and one that has played an important role for avian taxonomists over the years is plumage coloration. With the advent of electronic devices that can quickly and accurately quantify plumage coloration, the potential of using coloration as an identifier for distinct taxonomic groups, even when differences are subtle, becomes possible. In this study, we evaluated the degree to which plumage coloration differs among the four subspecies of the willow flycatcher Empidonax traillii, evaluated sources of variation, and considered the utility of plumage coloration to assign subspecies membership for individuals of unknown origin. We used a colorimeter to measure plumage coloration of 374 adult willow flycatchers from 29 locations across their breeding range in 2004 and 2005. We found strong statistical differences among the mean plumage coloration values of the four subspecies; however, while individuals tended to group around their respective subspecies’ mean color value, the dispersion of individuals around such means overlapped. Mean color values for each breeding site of the three western subspecies clustered together, but the eastern subspecies’ color values were dispersed among the other subspecies, rather than distinctly clustered. Additionally, sites along boundaries showed evidence of intergradation and intermediate coloration patterns. We evaluated the predictive power of colorimeter measurements on flycatchers by constructing a canonical discriminant model to predict subspecies origin of migrants passing through the southwestern U.S. Considering only western subspecies, we found that individuals can be assigned with reasonable certainty. Applying the model to migrants sampled along the Colorado River in Mexico and the U.S. suggests different migration patterns for the three western subspecies. We believe that the use of plumage coloration, as measured by electronic devices, can provide a powerful tool to look at ecological questions in a wide range of avian species.     

Persistence of song types in Darwin's finches,Geospiza fortis,over four decades

Learned bird songs evolve via cultural evolution, with song patterns transmitted across generations by imitative learning. In Darwin''s finches of the Galápagos Islands, males learn songs from their fathers, and song types can be maintained across multiple generations. However, little is known about the time frame over which specific song types are preserved, in the face of copy errors and corresponding modifications to song structure. Here we investigate cultural evolution in songs of male Geospiza fortis, at Academy Bay, Santa Cruz Island, comparing songs recorded in 1961 by R. Bowman (20 individuals) to those recorded in 1999 by J. Podos (16 individuals). For each individual, we characterized four timing and six frequency parameters, and assessed inter-individual variation in song structure using multivariate analysis. Several 1961 song types persisted into 1999, some with remarkable fidelity. Variation among song types was extensive during both years, and we detected no changes in 10 vocal parameters across the sampling period. These results illustrate temporal continuity in a culturally acquired trait, and raise questions about mechanisms that promote stability in song structure.     

Extracellular matrix metalloprotease inducer-expressing head and neck squamous cell carcinoma cells promote fibroblast-mediated type I collagen degradation in vitro

Until recently, tumor progression has been considered a multistep process defined by tumor cell mutations and the importance of the surrounding stroma poorly understood. It is now recognized that matrix-degrading enzymes that promote tumor cell invasion are elaborated by both tumor cells and fibroblasts in vivo. To determine the relative role of tumor cell-derived proteases compared with fibroblast-derived proteases, coculture experiments were done with each cell type using an in vitro model of type I collagen degradation. Head and neck squamous cell carcinoma cells in coculture with normal dermal fibroblasts showed matrix degradation, but neither cell type alone produced this effect. Manipulating the in vitro coculture environment showed that collagenolysis in this model was a result of fibroblast-derived matrix metalloproteases (MMP). To explore the possible role of extracellular matrix metalloprotease inducer (EMMPRIN) in this interaction, transfection of EMMPRIN into a cell line with low endogenous EMMPRIN expression was done and showed a significant increase in collagenolysis. Inhibition of collagenolysis with a tissue inhibitor of metalloprotease-2 (TIMP-2) and a synthetic furin inhibitor was observed but not with TIMP-1, which suggested a possible role for membrane type-1 MMP. These results suggest that fibroblast-derived MMPs but not those from tumor cells are important for in vitro collagenolysis and that this process is promoted by tumor cell-expressed EMMPRIN.     

Activity probe for in vivo profiling of the specificity of proteasome inhibitor bortezomib

Proteasome inhibitors, such as the dipeptide boronic acid bortezomib, are emerging as important tools in the treatment of the fatal hematologic malignancy multiple myeloma. Despite the recent US Food and Drug Administration approval of bortezomib (PS341, Velcade) for the treatment of refractory multiple myeloma, many of the basic pharmacologic parameters of bortezomib and its mode of action on myeloma cells remain to be determined. We describe the synthesis and use of a cell-permeant active site-directed probe, which allows profiling of proteasomal activities in living cells. When we compared proteasome activity patterns in cultured cells and crude cell extracts with this probe, we observed substantial differences, stressing the importance for bioassays compatible with live cells to ensure accuracy of such measurements. Using this probe, we investigated the in vivo subunit specificities of bortezomib and another inhibitor, MG132.     

Response of Drosophila suzukii (Diptera: Drosophilidae) to extreme heat and dryness

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Nonmarine aspects of the Cambrian Tonto Group of the Grand Canyon, USA, and broader implications

A re-examination of the classic time-transgressive model of the Cambrian Tonto Group of the Grand Canyon challenges some of the basic assumptions regarding strandline migration during the Sauk transgression, the applicability of sequence stratigraphy to epicratonic deposits, and the criteria by which siliciclastic deposits of the North American Cambrian system are categorized as marine. Indicators for high short-term depositional rates, coupled with the complex splay and coalescence of meter-scale parasequence architectures, detract from the shoreline migration and deepening seas model that has held sway for over 60 years. Ostensibly marine signatures, represented by sparse and fragmentary trilobite fossils and abundant bedding plane trace fossils, are closely associated with nonmarine signatures, represented by nonmarine palynoflora and clay mineral assemblages, and highly oxidized paleoweathering profiles. The vast extent of three-dimensional exposure of the Cambrian section in the Grand Canyon shows a paleogeography not of a single discrete shoreline translated laterally with rising and falling sea-level, but of a single mosaic setting of emergent shoals and rocky peaks, broad fluvial and tidal channels, and shallow pools and interchannel flats. Much detail concerning sediment dynamics and paleoenvironment is lost or overlooked when summary terms like “marginal marine” or “nearshore” are applied to such settings. It is suggested here that the Tonto Group, with its mixed marine and nonmarine attributes, and considering its historic role as a teaching model, be viewed not as an exceptional Cambrian deposit, but as an exemplar of epicratonic deposits on a pre-vegetated landscape.