Metastatic colonization potential of primary tumour cells in mice.

A model has been developed for studying the capability of cells from primary murine mammary tumours to establish colonies in distant organs. The model involves the i.v. inoculation of disaggregated tumour cells into autologous and syngeneic recipients. The results show that the metastatic colonization potential of cells from a given tumour is consistent within the animals of an inoculated batch. Also, the findings are uniform in the autologous host and the syngeneic recipients. Tumours vary in their colonization potential and can be classified in 2 main groups designated high and low. These findings indicate that: (i) cells from 37% of mammary tumours can heavily colonize the lungs when inoculated i.v., even though the incidence of metastatic spread of these tumours in the undisturbed animal is almost zero. Thus, the relative infrequency of spontaneous metastasis from murine mammary tumours is not due to inability of the tumour cells to survive and colonize once free in the blood stream; and (ii) the colonization potential of the tumours is an intrinsic property of the tumour cells rather than of the host, whose prior acquaintance with the cells does not seem to confer resistance to colonization. The model presents opportunities for identification of possible differences between tumours of high and low colonization potential, and is being used to study cellular properties which favour colonization of distant organs by comparison of observations in vitro with the behaviour of cells from the same tumour in vivo

Correlation of collagenase secretion with metastatic-colonization potential in naturally occurring murine mammary tumours.

We report evidence for the secretion of a true mammalian collagenase active against Type 1 collagen, by naturally-occurring mammary tumours of the mouse and show that tumours capable of heavily colonizing the lungs secrete significantly more of this enzyme than those with low pulmonary-colonization potential, or non-neoplastic proliferating (e.g. lactating) mammary tissue. Plasminogen activator is secreted in greater quantity by tumours than by normal tissues, but there is no significant difference in the amount produced by tumours with high or low pulmonary-colonization potential. These findings correlate well with our earlier morphological observations of marked connective tissue destruction in the vicinity of invading tumours and metastatic deposits, and indicate that protease release is implicated in the mechanism of tumour spread

Speculations on the application of foliar 13C discrimination to reveal groundwater dependency of vegetation and provide estimates of root depth and rates of groundwater use

© Author(s) 2018. Groundwater-dependent vegetation is globally distributed, having important ecological, social, and economic value. Along with the groundwater resources upon which it depends, this vegetation is under increasing threat through excessive rates of groundwater extraction. In this study we examined one shallow-rooted and two deep-rooted tree species at multiple sites along a naturally occurring gradient in depth-to-groundwater. We measured (i) stable isotope ratios of leaves (δ 13C), xylem, and groundwater (δ 2H and δ 18O); and (ii) leaf-vein density. We established that foliar discrimination of 13C (Δ13C) is a reliable indicator of groundwater use by vegetation and can also be used to estimate rooting depth. Through comparison with a continental-scale assessment of foliar Δ13C, we also estimated the upper limits to annual rates of groundwater use. We conclude that maximum rooting depth for both deep-rooted species ranged between 9.4 and 11.2 m and that annual rates of groundwater use ranged from ca. 1400 to 1700 mm for Eucalyptus camaldulensis and from 600 to 900 mm for Corymbia opaca. Several predictions about hydraulic and leaf traits arising from the conclusion that these two species made extensive use of groundwater were supported by additional independent studies of these species in central Australia

Disk wakes in nonlinear stratification

Nonlinearity of density stratification modulates buoyancy effects. We report results from a body-inclusive large eddy simulation (LES) of a wake in nonlinear stratification, specifically for a circular disk at diameter-based Reynolds number ($Re$) of $5000$. Five density profiles are considered; the benchmark has linear stratification and the other four have hyperbolic tangent profiles to model a pycnocline. The disk moves inside the central core of the pycnocline in two of those four cases and, in the other two cases with {a} shifted density profile, the disk moves partially/completely outside the pycnocline. The maximum buoyancy frequency ($N_{max}$) for all the profiles is the same. The first part of the study investigates the centered cases. Nonuniform stratification results in increasing wake turbulence relative to the benchmark owing to reduced suppression of turbulence production as well as the wave trapping in the pycnocline. Steady lee waves are also quantified to understand limitations of linear theory. The second part pays attention to the effect of a relative shift between the pycnocline and the disk. The wake defect velocity decays faster in the cases with a shift. The effect of disk location on the Kelvin wake waves (a family of steady waves within the pycnocline) and its modal form is obtained and explained by solving the Taylor-Goldstein equation. The family of unsteady internal gravity waves that are generated by the wake is also studied and the effect of disk shift is quantified.Comment: 23 pages, 15 plots, submitted to Journal of Fluid Mechanic

Rare’s Conservation Campaigns: Community Decision Making and Public Participation for Behavioral Change in Indonesia, China, and Latin America

In this chapter we explore the ways in which Rare, an international non-profit organization, uses institutional, practical, and local knowledge as a symbolic resource to create environmental change. Rare’s approach involves identifying human behaviors that cause threats to biodiversity, using social science research to identify community-based and public participation solutions to change these behaviors, launching a Pride campaign designed to instill pride within a local community and to facilitate the removal of barriers to conservation, and adapting conservation solutions on a broader scale. Such an approach enables Rare and its campaign managers to draw on expertise from all kinds of backgrounds, experiences, and different knowledge bases that allows for contextual and effective behavior change in conservation rooted in public participation and community empowerment. Rare partners with The University of Texas at El Paso to offer a master’s degree program for Pride campaign managers, and we have collected data while supervising the coursework and assignments for this program through qualitative approaches, such as ethnography, interviews, and field site visits, and quantitative approaches, such as knowledge-attitude-practice (KAP) surveys implemented by our students (the Rare campaign managers). Based on these data, we offer case studies from three regions where Rare works: Indonesia, Latin America, and China. While conservation efforts often focus on tangible material resources, limiting the available options for change, we ultimately argue that Rare’s focus on symbolic resources in Pride campaigns uses the paradigm of constructed potentiality (Foss & Foss, 2011), generating multiple options for creating change through public participation

Human cytomegalovirus pUL29/28 and pUL38 repression of p53-regulated p21CIP1 and caspase 1 promoters during infection

During infection by human cytomegalovirus (HCMV), the tumor suppressor protein p53, which promotes efficient viral gene expression, is stabilized. However, the expression of numerous p53-responsive cellular genes is not upregulated. The molecular mechanism used to manipulate the transcriptional activity of p53 during infection remains unclear. The HCMV proteins IE1, IE2, pUL44, and pUL84 likely contribute to the regulation of p53. In this study, we used a discovery-based approach to identify the protein targets of the HCMV protein pUL29/28 during infection. Previous studies have demonstrated that pUL29/28 regulates viral gene expression by interacting with the chromatin remodeling complex NuRD. Here, we observed that pUL29/28 also associates with p53, an additional deacetylase complex, and several HCMV proteins, including pUL38. We confirmed the interaction between p53 and pUL29/28 in both the presence and absence of infection. HCMV pUL29/28 with pUL38 altered the activity of the 53-regulatable p21CIP1 promoter. During infection, pUL29/28 and pUL38 contributed to the inhibition of p21CIP1 as well as caspase 1 expression. The expression of several other p53-regulating genes was not altered. Infection using a UL29-deficient virus resulted in increased p53 binding and histone H3 acetylation at the responsive promoters. Furthermore, expression of pUL29/28 and its interacting partner pUL38 contributed to an increase in the steady-state protein levels of p53. This study identified two additional HCMV proteins, pUL29/28 and pUL38, which participate in the complex regulation of p53 transcriptional activity during infection