Individual, Population, and Community-Level Drivers of Cheetah (\u3ci\u3eAcinonyx jubatus\u3c/i\u3e) Population Dynamics

Ecological processes can operate at different scales; individual characteristics can scale-up and affect individual performance, which in turn can influence population and community-level processes. Similarly, processes at the community or population level can affect individual characteristics. For mesopredators, the majority of prior research has focused on how top-down regulation by apex predators affects population dynamics. In contrast, less is known about how mesopredators can be affected by processes happening at the individual, population, and community-level simultaneously. I studied a population of cheetahs (Acinonyx jubatus) in the Mun-Ya-Wana Conservancy, South Africa to better understand how ecological processes across multiple scales can affect mesopredators. In Chapter 1, I investigated population-level drivers of survival, reproduction, and recruitment of cheetahs using a 25-year dataset. I found that demographic drivers were complex and context dependent. Specifically, cheetah monthly survival was best described by lion density and prey density, but opposite of predicted relationships; both adults and cubs had the highest survival when lion densities were highest and prey densities were lowest. I found that there were no strong drivers of litter size, but that cheetahs had the highest recruitment during times of low cheetah density and low prey density. Next, in Chapter 2 I considered how individual habitat use of cheetahs can scale-up and influence population survival. I assessed habitat use at short-term and long-term scales in relation to lion density, prey density, and habitat complexity and used these spatial covariates to predict survival. I found that over both the short-term and the long-term, cheetah survival was highest in areas with open vegetation, and that over the long-term cheetah survival was lowest in areas of high lion density. In Chapter 3, I examined how spatial and temporal variation in predation risk, as well as habitat complexity, can influence cheetah anti-predator behaviors. Using a playback experiment, I manipulated short-term risk in areas of varying long-term risk and assessed cheetah behavioral responses. I found that cheetah vigilance was not associated with long-term predation risk, but that cheetahs responded to short-term risk by being vigilant or fleeing. Additionally, habitat complexity affected cheetah anti-predator behaviors, with cheetah more vigilant in open areas and more likely to flee from lion sounds in closed vegetation and from leopard sounds in open vegetation. Finally, in Chapter 4 I investigated how habitat disturbance can affect carnivore coexistence and suppression. I used prescribed burning to experimentally increase prey densities and monitored how individual species, as well as large carnivores and small carnivores as a whole, respond to burning. I found that some large and small carnivores increased use of burned areas post-fire, but that most carnivores were unaffected by burning. Small carnivores may have experienced a suppression of opportunity, where they were not able to benefit from increased prey in burned areas because of high lion use in these areas. Collectively, my research highlights the need to consider multiple scales of ecological processes to understand mesopredator population dynamics. Specifically, I show that top-down effects on mesopredators are context-dependent and depend on the scale of investigation, so understanding how multiple factors simultaneously affect mesopredator populations is critical

Becoming women: awareness of migration and double loyalty

"Based on two case studies of adolescent daughters of migrant and mixed families in Bavaria (Germany) and in Veneto (Italy), the paper aims to study how the daughters solve the conflicting interactions between the contents of the transmission and of the socialization. Focused mostly on gendered interactions and on a sense of belonging, the reflection investigates if and how structural elements (e.g.: family configuration, national context and migration trajectories of parents) impact on continuity and discontinuity in passing on values and other sets of information. The observation of 'status passages' and 'socio-ecological transitions' in and between private and public spheres thanks to the analysis of life histories are suitable to grasp the specific effects of handing down and its interaction with the socialization over generations. This approach entails the articulation of 'time' (namely the interplay between past and present) and 'space' (namely the private and public spheres) allowing retracing the outline of the 'generational work' that each family performs consciously and unconsciously. In different geographical and socio-cultural contexts as well as in different family patterns, parenting and adolescent dynamics reveal common features. By pointing out the restructuration that adolescence imposes in life courses, we show that it is the meaning given to the parental experience of migration that entails specific form of 'loyalty' due to emotional and juridical (de)nationalized belonging, as well as to previous experiences of socialization and discrimination. The originality of the reflection is connected to the patterns of the families compared. The authors widen the concept of migration classically employed in academia introducing the innovative concept of 'migration of contact'." (author's abstract

Context-dependency in carnivore co-occurrence across a multi-use conservation landscape

This research was funded by South Africa's National Research Foundation (UID: 107099 and 115040), African Institute for Conservation Ecology, National Geographic Society (EC-314R-18) and Wild Tomorrow Fund. G.C.-S. and M.S.-R. were funded by Fundacão para a Ciência e a Tecnologia in the frame of a doctoral grant (PD/BD/114037/2015) and the research unit (UID/BIA/00329/2019), respectively.Carnivore intraguild dynamics depend on a complex interplay of environmental affinities and interspecific interactions. Context-dependency is commonly expected with varying suites of interacting species and environmental conditions but seldom empirically described. In South Africa, decentralized approaches to conservation and the resulting multi-tenure conservation landscapes have markedly altered the environmental stage that shapes the structure of local carnivore assemblages. We explored assemblage-wide patterns of carnivore spatial (residual occupancy probability) and temporal (diel activity overlap) co-occurrence across three adjacent wildlife-oriented management contexts?a provincial protected area, a private ecotourism reserve, and commercial game ranches. We found that carnivores were generally distributed independently across space, but existing spatial dependencies were context-specific. Spatial overlap was most common in the protected area, where species occur at higher relative abundances, and in game ranches, where predator persecution presumably narrows the scope for spatial asymmetries. In the private reserve, spatial co-occurrence patterns were more heterogeneous but did not follow a dominance hierarchy associated with higher apex predator densities. Pair-specific variability suggests that subordinate carnivores may alternate between pre-emptive behavioral strategies and fine-scale co-occurrence with dominant competitors. Consistency in species-pairs diel activity asynchrony suggested that temporal overlap patterns in our study areas mostly depend on species' endogenous clock rather than the local context. Collectively, our research highlights the complexity and context-dependency of guild-level implications of current management and conservation paradigms; specifically, the unheeded potential for interventions to influence the local network of carnivore interactions with unknown population-level and cascading effects.Publisher PDFPeer reviewe

Detection and isolation of airborne SARS-CoV-2 in a hospital setting

Transmission mechanisms for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are incompletely understood. In particular, aerosol transmission remains unclear, with viral detection in air and demonstration of its infection potential being actively investigated. To this end, we employed a novel electrostatic collector to sample air from rooms occupied by COVID-19 patients in a major Swedish hospital. Electrostatic air sampling in conjunction with extraction-free, reverse-transcriptase polymerase chain reaction (hid-RT-PCR) enabled detection of SARS-CoV-2 in air from patient rooms (9/22; 41%) and adjoining anterooms (10/22; 45%). Detection with hid-RT-PCR was concomitant with viral RNA presence on the surface of exhaust ventilation channels in patients and anterooms more than 2 m from the COVID-19 patient. Importantly, it was possible to detect active SARS-CoV-2 particles from room air, with a total of 496 plaque-forming units (PFUs) being isolated, establishing the presence of infectious, airborne SARS-CoV-2 in rooms occupied by COVID-19 patients. Our results support circulation of SARS-CoV-2 via aerosols and urge the revision of existing infection control frameworks to include airborne transmission

Solid lipid nanoparticles of cholesteryl butyrate inhibit the proliferation of cancer cells in vitro and in vivo models.

BACKGROUND AND PURPOSE: Solid lipid nanoparticles containing cholesteryl butyrate (cholbut SLN) can be a delivery system for the anti-cancer drug butyrate. These nanoparticles inhibit adhesion of polymorphonuclear and tumour cells to endothelial cells and migration of tumour cells, suggesting that they may act as anti-inflammatory and anti-tumour agents. Here we have evaluated the effects of cholbut SLN on tumour cell growth using in vitro and in vivo models. EXPERIMENTAL APPROACH: Cholbut SLNs were incubated with cultures of four tumour cell lines, and cell growth was analysed by assessing viability, clonogenic capacity and cell cycle. Effects on intracellular signalling was assessed by Western blot analysis of Akt expression. The in vivo anti-tumour activity was measured in two models of PC-3 cell xenografts in SCID/Beige mice. KEY RESULTS: Cholbut SLN inhibited tumour cell line viability, clonogenic activity, Akt phosphorylation and cell cycle progression. In mice injected i.v. with PC3-Luc cells and treated with cholbut SLN, . in vivo optical imaging and histological analysis showed no metastases in the lungs of the treated mice. In another set of mice injected s.c. with PC-3 cells and treated with cholbut SLN when the tumour diameter reached 2 mm, analysis of the tumour dimensions showed that treatment with cholbut SLN substantially delayed tumour growth. CONCLUSION AND IMPLICATIONS: Cholbut SLN were effective in inhibiting tumour growth in vitro and in vivo. These effects may involve, in part, inhibition of Akt phosphorylation, which adds another mechanism to the activity of this multipotent drug

Paclitaxel-Loaded Nanosponges Inhibit Growth and Angiogenesis in Melanoma Cell Models

This study investigated the effects of free paclitaxel (PTX) and PTX-loaded in pyromellitic nanosponges (PTX-PNS) in reducing in vitro and in vivo melanoma cell growth and invasivity, and in inhibiting angiogenesis. To test the response of cells to the two PTX formulations, the cell viability was evaluated by MTT assay in seven continuous cell lines, in primary melanoma cells, both in 2D and 3D cultures, and in human umbilical vein endothelial cells (HUVECs) after exposure to different concentrations of PTX or PTX-PNS. Cell motility was assessed by a scratch assay or Boyden chamber assay, evaluating cell migration in presence or absence of diverse concentrations of PTX or PTX-PNS. The effect of PTX and PTX-PNS on angiogenesis was evaluated as endothelial tube formation assay, a test able to estimate the formation of three-dimensional vessels in vitro. To assess the anticancer effect of PTX and PTX-PNS in in vivo experiments, the two drug formulations were tested in a melanoma mouse model obtained by B16-BL6 cell implantation in C57/BL6 mice. Results obtained were as follows: 1) MTT analysis revealed that cell proliferation was more affected by PTX-PNS than by PTX in all tested cell lines, in both 2D and 3D cultures; 2) the analysis of the cell migration showed that PTX-PNS acted at very lower concentrations than PTX; 3) tube formation assay showed that PTX-PNS were more effective in inhibiting tube formation than free PTX; and 4) in vivo experiments demonstrated that tumor weights, volumes, and growth were significantly reduced by PTX-PNS treatment with respect to PTX; the angiogenesis and the cell proliferation, detected in the tumor samples with CD31 and Ki-67 antibodies, respectively, indicated that, in the PTX-PNS-treated tumors, the tube formation was inhibited, and a low amount of proliferating cells was present. Taken together, our data demonstrated that our new PTX nanoformulation can respond to some important issues related to PTX treatment, lowering the anti-tumor effective doses and increasing the effectiveness in inhibiting melanoma growth in vivo

Enhanced cytotoxic effect of camptothecin nanosponges in anaplastic thyroid cancer cellsin vitroandin vivoon orthotopic xenograft tumors

Anaplastic carcinoma of the thyroid (ATC) is a lethal human malignant cancer with median survival of 6 months. To date, no treatment has substantially changed its course, which makes urgent need for the development of novel drugs or novel formulations for drug delivery. Nanomedicine has enormous potential to improve the accuracy of cancer therapy by enhancing availability and stability, decreasing effective doses and reducing side effects of drugs. Camptothecin (CPT) is an inhibitor of DNA topoisomerase-I with several anticancer properties but has poor solubility and a high degradation rate. Previously, we reported that CPT encapsulated in β-cyclodextrin-nanosponges (CN-CPT) increased solubility, was protected from degradation and inhibited the growth of prostate tumor cells both in vitro and in vivo. The aim of this study was to extend that work by assessing the CN-CPT effectiveness on ATC both in vitro and in vivo. Results showed that CN-CPT significantly inhibited viability, clonogenic capacity and cell-cycle progression of ATC cell lines showing a faster and enhanced effect compared to free CPT. Moreover, CN-CPT inhibited tumor cell adhesion to vascular endothelial cells, migration, secretion of pro-angiogenic factors (IL-8 and VEGF-α), expression of β-PIX, belonging to the Rho family activators, and phosphorylation of the Erk1/2 MAPK. Finally, CN-CPT significantly inhibited the growth, the metastatization and the vascularization of orthotopic ATC xenografts in SCID/beige mice without apparent toxic effects in vivo. This work extends the previous insight showing that β-cyclodextrin-nanosponges are a promising tool for the treatment of ATC

B7h triggering inhibits the migration of tumor cell lines

Vascular endothelial cells (ECs) and several cancer cells express B7h, which is the ligand of the ICOS T cell costimulatory molecule. We have previously shown that B7h triggering via a soluble form of ICOS (ICOS-Fc) inhibits the adhesion of polymorphonuclear and tumor cell lines to HUVECs; thus, we suggested that ICOS-Fc may act as an anti-inflammatory and antitumor agent. Because cancer cell migration and angiogenesis are crucial for metastasis dissemination, the aim of this work was to evaluate the effect of ICOS-Fc on the migration of cancer cells and ECs. ICOS-Fc specifically inhibited the migration of HUVECs, human dermal lymphatic ECs, and the HT29, HCT116, PC-3, HepG2, JR8, and M14 tumor cell lines expressing high levels of B7h, whereas it was ineffective in the RPMI7932, PCF-2, LM, and BHT-101 cell lines expressing low levels of B7h. Furthermore, ICOS-Fc downmodulated hepatocyte growth factor facilitated the epithelial-to-mesenchymal transition in HepG2 cells. Moreover, ICOS-Fc downmodulated the phosphorylation of focal adhesion kinase and the expression of \u3b2-Pix in both HUVECs and tumor cell lines. Finally, treatment with ICOS-Fc inhibited the development of lung metastases upon injection of NOD-SCID-IL2R\u3b3null mice with CF-PAC1 cells, as well as C57BL/6 mice with B16-F10 cells. Therefore, the B7h-ICOS interaction may modulate the spread of cancer metastases, which suggests the novel use of ICOS-Fc as an immunomodulatory drug. However, in the B16-F10-metastasized lungs, ICOS-Fc also increased IL-17A/RORc and decreased IL-10/Foxp3 expression, which indicates that it also exerts positive effects on the antitumor immune response

Covid-19 And Rheumatic Autoimmune Systemic Diseases: Role of Pre-Existing Lung Involvement and Ongoing Treatments

The Covid-19 pandemic may have a deleterious impact on patients with autoimmune systemic diseases (ASD) due to their deep immune-system alterations