Movements of four native Hawaiian birds across a naturally fragmented landscape

Animals often increase their fitness by moving across space in response to temporal variation in habitat quality and resource availability, and as a result of intra and inter‐specific interactions. The long‐term persistence of populations and even whole species depends on the collective patterns of individual movements, yet animal movements have been poorly studied at the landscape level. We quantified movement behavior within four native species of Hawaiian forest birds in a complex lava‐fragmented landscape: Hawai?i ‘amakihi Chlorodrepanis virens, ‘oma‘o Myadestes obscurus, ‘apapane Himatione sanguinea, and ‘i‘iwi Drepanis coccinea. We evaluated the relative importance of six potential intrinsic and extrinsic drivers of movement behavior and patch fidelity: 1) forest fragment size, 2) the presence or absence of invasive rats (Rattus sp.), 3) season, 4) species, 5) age, and 6) sex. The study was conducted across a landscape of 34 forest fragments varying in size from 0.07 to 12.37 ha, of which 16 had rats removed using a treatment‐control design. We found the largest movements in the nectivorous ‘apapane and ‘i‘iwi, intermediate levels in the generalist Hawai?i ‘amakihi, and shortest average movement for the ‘oma‘o, a frugivore. We found evidence for larger patch sizes increasing patch fidelity only in the ‘oma‘o, and an effect of rat‐removal increasing patch fidelity of Hawai?i ‘amakihi only after two years of rat‐removal. Greater movement during the non‐breeding season was observed in all species, and season was an important factor in explaining higher patch fidelity in the breeding season for ‘apapane and ‘i‘iwi. Sex was important in explaining patch fidelity in ‘oma‘o only, with males showing higher patch fidelity. Our results provide new insights into how these native Hawaiian species will respond to a changing environment, including habitat fragmentation and changing distribution of threats from climate change.     

Untangling the cecal microbiota of feral chickens by culturomic and metagenomic analyses

Different factors may modulate the gut microbiota of animals. In any particular environment, diet, genetic factors and human influences can shape the bacterial communities residing in the gastrointestinal tract. Metagenomic approaches have significantly expanded our knowledge on microbiota dynamics inside hosts, yet cultivation and isolation of bacterial members of these complex ecosystems may still be necessary to fully understand interactions between bacterial communities and their host. A dual approach, involving culture‐independent and ‐dependent techniques, was used here to decipher the microbiota communities that inhabit the gastro intestinal tract of free‐range, broiler and feral chickens. In silico analysis revealed the presence of a core microbiota that is typical of those animals that live in different geographical areas and that have limited contact with humans. Anthropic influences guide the metabolic potential and the presence of antibiotic resistance genes of these different bacterial communities. Culturomics attempts, based on different cultivation conditions, were applied to reconstruct in vitro the microbiota of feral chickens. A unique strain collection representing members of the four major phyla of the poultry microbiota was assembled, including bacterial strains that are not typically retrieved from the chicken gut.     

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.     

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.     

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.     

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.     

Divergent movement patterns of adult and juvenile ‘Akohekohe,an endangered Hawaiian Honeycreeper

The movement patterns of birds across a landscape are often highly variable and influenced by complex interactions between individuals and environments. Because periods of movement can be marked by high mortality, especially among juvenile birds, understanding these patterns may be vital for the conservation of many bird species. However, these patterns can be challenging to quantify. We used radio-telemetry to document the movement patterns of ‘Akohekohe (Palmeria dolei), an endangered Hawaiian Honeycreeper endemic to Maui Island, Hawai'i. This species is believed to be highly susceptible to mosquito-transmitted avian malaria (Plasmodium relictum) and only breeds in high-elevation wet forests on the windward side of east Maui (> 1715 m) that serve as mosquito-free refugia. Over a 2-yr period (2013–2014), we used radio-telemetry and resightings of color-banded birds to track the movements of juveniles (N = 11) and adults (N = 24) and quantified home ranges with minimum convex polygons (MCP) and 95% fixed kernels (KHR). Movement patterns and home range sizes of adult and juvenile ‘Akohekohe were significantly different, with adults having relatively small home ranges (0.57 ha, MCP; 1.09 ha, KHR) and juveniles moving greater distances and having larger home ranges (25.02 ha, MCP; 90.56 ha, KHR). Only juveniles moved into lower-elevation forests that can support mosquito populations, at least seasonally. The absence of adults in this transitional malaria zone suggests that adult ‘Akohekohe cannot maintain long-term home ranges in areas with an increased risk of malaria infection. In addition, the long-distance movements of juveniles during the post-fledging, pre-breeding period likely increases their risk of contracting avian malaria and could be a key factor limiting the population of this species.