Predictive systems ecology

Human societies, and their well-being, depend to a significant extent on the state of the ecosystems that surround them. These ecosystems are changing rapidly usually in response to anthropogenic changes in the environment. To determine the likely impact of environmental change on ecosystems and the best ways to manage them, it would be desirable to be able to predict their future states. We present a proposal to develop the paradigm of predictive systems ecology, explicitly to understand and predict the properties and behaviour of ecological systems. We discuss the necessary and desirable features of predictive systems ecology models. There are places where predictive systems ecology is already being practised and we summarize a range of terrestrial and marine examples. Significant challenges remain but we suggest that ecology would benefit both as a scientific discipline and increase its impact in society if it were to embrace the need to become more predictive.     

In Vivo Quantitative Assessment of Myocardial Structure,Function, Perfusion and Viability Using Cardiac Micro-computed Tomography

The use of Micro-Computed Tomography (MicroCT) for in vivo studies of small animals as models of human disease has risen tremendously due to the fact that MicroCT provides quantitative high-resolution three-dimensional (3D) anatomical data non-destructively and longitudinally. Most importantly, with the development of a novel preclinical iodinated contrast agent called eXIA160, functional and metabolic assessment of the heart became possible. However, prior to the advent of commercial MicroCT scanners equipped with X-ray flat-panel detector technology and easy-to-use cardio-respiratory gating, preclinical studies of cardiovascular disease (CVD) in small animals required a MicroCT technologist with advanced skills, and thus were impractical for widespread implementation. The goal of this work is to provide a practical guide to the use of the high-speed Quantum FX MicroCT system for comprehensive determination of myocardial global and regional function along with assessment of myocardial perfusion, metabolism and viability in healthy mice and in a cardiac ischemia mouse model induced by permanent occlusion of the left anterior descending coronary artery (LAD).     

Predicting and validating a model of suppressor of IKKepsilon through biophysical characterization

Suppressor of IKKepsilon (SIKE) is a 207 residue protein that is implicated in the TLR3‐TANK‐binding kinase‐1‐mediated response to viral infection. SIKE's function in this pathway is unknown, but SIKE forms interactions with two distinct cytoskeletal proteins, α‐actinin and tubulin, and SIKE knockout reduces cell migration. As structure informs function and in the absence of solved structural homologs, our studies were directed toward creating a structural model of SIKE through biochemical and biophysical characterization to probe and interrogate SIKE function. Circular dichroism revealed a primarily (73%) helical structure of minimal stability (<T_m > =32°C) but reversibly denatured. Limited proteolysis (LP) and chemical modification identified the N‐terminal 2/3 of the protein as dynamic and accessible, whereas size exclusion chromatography (SEC) confirmed three homo‐oligomeric species. SEC coupled to chemical crosslinking characterized the primary species as dimeric, a secondary hexameric species, and a higher order aggregate/polymer. Fluorescence polarization using intrinsic tryptophan fluorescence contextualized the anisotropy value for the SIKE dimer (molecular weight 51.8 kDa) among proteins of known structure, bovine serum albumin (BSA; 66 kDa), and glutamate dehydrogenase (GDH; 332 kDa). Radii of gyration for BSA and GDH provided exclusionary values for SIKE tertiary and dimeric quaternary models that otherwise conformed to secondary structure, LP, and modification data. Dimeric quaternary models were further culled using acrylamide quenching data of SIKE's single tryptophan that showed a single, protected environment. The low cooperativity of folding and regions of dynamic and potentially disordered structure advance the hypothesis that SIKE forms a conformational ensemble of native states that accommodate SIKE's interactions with multiple, distinct protein‐binding partners.     

Status and distribution of jaguarundi in Texas and Northeastern México: Making the case for extirpation and initiation of recovery in the United States

The jaguarundi (Puma yagouaroundi) is a small felid with a historical range from central Argentina through southern Texas. Information on the current distribution of this reclusive species is needed to inform recovery strategies in the United States where its last record was in 1986 in Texas. From 2003 to 2021, we conducted camera‐trap surveys across southern Texas and northern Tamaulipas, México to survey for medium‐sized wild cats (i.e., ocelots [Leopardus pardalis], bobcats [Lynx rufus], and jaguarundi). After 350,366 trap nights at 685 camera sites, we did not detect jaguarundis at 16 properties or along 2 highways (1050 km²) in Texas. However, we recorded 126 jaguarundi photographic detections in 15,784 trap nights on 2 properties (125.3 km²) in the northern Sierra of Tamaulipas, Tamaulipas, México. On these properties, latency to detection was 72 trap nights, with a 0.05 probability of detection per day and 0.73 photographic event rate every 100 trap nights. Due to a lack of confirmed class I sightings (e.g., specimen, photograph) in the 18 years of this study, and no other class I observations since 1986 in the United States, we conclude that the jaguarundi is likely extirpated from the United States. Based on survey effort and results from México, we would have expected to detect jaguarundis over the course of the study if still extant in Texas. We recommend that state and federal agencies consider jaguarundis as extirpated from the United States and initiate recovery actions as mandated in the federal jaguarundi recovery plan. These recovery actions include identification of suitable habitat in Texas, identification of robust populations in México, and re‐introduction of the jaguarundi to Texas.     

Sexual selection and animal personality

Consistent individual behavioural tendencies, termed “personalities”, have been identified in a wide range of animals. Functional explanations for personality have been proposed, but as yet, very little consideration has been given to a possible role for sexual selection in maintaining differences in personality and its stability within individuals. We provide an overview of the available literature on the role of personality traits in intrasexual competition and mate choice in both human and non‐human animals and integrate this into a framework for considering how sexual selection can generate and maintain personality. For this, we consider the evolution and maintenance of both main aspects of animal personality: inter‐individual variation and intra‐individual consistency.     

Neutrophil cathepsin G promotes detachment-induced cardiomyocyte apoptosis via a protease-activated receptor-independent mechanism

Cathepsin G is a neutrophil-derived serine protease that contributes to tissue damage at sites of inflammation. The actions of cathepsin G are reported to be mediated by protease-activated receptor (PAR)-4 (a thrombin receptor) in human platelets. This study provides the first evidence that cathepsin G promotes inositol 1,4,5-trisphosphate accumulation, activates ERK, p38 MAPK, and AKT, and decreases contractile function in cardiomyocytes. Because some cathepsin G responses mimic cardiomyocyte activation by thrombin, a role for PARs was considered. Cathepsin G markedly activates phospholipase C and p38 MAPK in cardiomyocytes from PAR-1-/- mice, but it fails to activate phospholipase C, ERK, p38 MAPK, or AKT in PAR-1- or PAR-4-expressing PAR-1-/- fibroblasts (which display robust responses to thrombin). These results argue that PAR-1 does not mediate the actions of cathepsin G in cardiomyocytes, and neither PAR-1 nor PAR-4 mediates the actions of cathepsin G in fibroblasts. Of note, prolonged incubation of cardiomyocytes with cathepsin G results in the activation of caspase-3, cleavage of FAK and AKT, sarcomeric disassembly, cell rounding, cell detachment from underlying matrix, and morphologic features of apoptosis. Inhibition of Src family kinases or caspases (with PP1 or benzyloxycarbonyl-VAD-fluoromethyl ketone, respectively) delays FAK and AKT cleavage and cardiomyocyte detachment from substrate. Collectively, these studies describe novel cardiac actions of cathepsin G that do not require PARs and are predicted to assume functional importance at sites of interstitial inflammation in the heart.     

Direct coronary arterial stenting without predilatation in patients with coronary heart disease

The study was undertaken to evaluate the safety and efficiency of direct stenting versus routine stenting with predilation. It included 133 patients. By the decision of operators, direct stenting was conducted in 66 patients (71 stenoses) (Group 1). The remaining 67 patients (73 stenoses) underwent routine stenting with predilation (Group 2). The initial angiographic success of stenting was 100% in Group 1 and 98 in Group 2. Complications were absent. In the direct stenting group, technical problems occurred during a session in 9 (12%) cases. In this group the mean duration of fluoroscopy and the total duration of a session were much less than in the routine stenting group. The mean number of balloons used at dilation per stenosis and the number of dilation sessions per stenosis were much lower in Group 1 than in Group 2. The results of quantitative angiogram analysis before and after a session were similar in both patient groups. Six months following stenting, angiographic restenosis occurred in 7 (10%) patients in Group 1 and in 9 (12%) in Group 2. Direct stenting is a safe and effective treatment for non-occlusive coronary lesions without marked kinks and calcinosis. Direct stenting reduces the duration of fluoroscopy and the total duration of an operation by 50 and 22%, respectively, as compared to predilation stenting.     

Intracytoplasmic injection of frozen-thawed epididymal spermatozoa in a nonhuman primate model,the cynomolgus monkey (Macaca fascicularis)

Intracytoplasmic sperm injection (ICSI) with frozen-thawed epididymal spermatozoa was performed in the cynomolgus monkey (Macacafascicularis) to produce embryos in vitro. Eleven sexually mature females were hyperstimulated with an GnRH agonist (1.8 mg active triptorelin per 2 kg body weight), followed (2 weeks later) by rFSH (37.5 IU per 2 kg daily) for 12 days, and finally 1000 IU of hCG. Epididymal spermatozoa were collected from a single adult male monkey. The first stimulation cycle resulted in 90 oocytes; 70% of which were metaphase II (MII). Sixty-four percent of these MII oocytes were fertilized. Comparing ovarian response of five monkeys that underwent a second stimulation cycle there was an increase in oocyte quantity (13.2 versus 9.2 oocytes per monkey) but the percentage of MII oocytes remained the same at 58%. Fertilization and cleavage rates were also reduced but there was an increase in the number of embryos available for transfer. Overall, four monkeys became pregnant resulting in the birth of two healthy infants and two abortions. These findings show that ovarian stimulation by GnRH-rFSH did not compromise the developmental competence of the oocytes; effective combination of cryopreservation of epididymal spermatozoa and ICSI is possible in nonhuman primate reproduction, and thus has potential application in the conservation of highly endangered nonhuman primate species, and the cynomolgus monkey is a reliable biomedical research model to study the potential risks and benefits associated with assisted reproductive techniques prior to approval for clinical trials on humans.