A patch—clamp study of the action of a nitromethylene heterocycle insecticide on cockroach neurones growing in vitro

The mode of action of a nitromethylene heterocycle (NMH) insecticide was studied by patch–clamp techniques using cockroach embryonic cultures as an experimental model. Under whole-cell recordings, this compound elicited inward currents resembling those induced by O-acetylcholine (ACh). The reversal potentials for both ACh and the NMH were similar, suggesting that the inward currents induced by both were carried by the same species of ion. Pharmacological investigations of NMH-induced responses revealed that the insecticidal action of this compound is exerted through agonistic action at the nicotinic acetylcholine receptor. Single-channel studies were also performed to study the interaction of NMH with the nicotinic-receptor-coupled ion channel.     

Developing a family engagement plan for Native Hawaiian and Pacific Islander STEM students in higher education: A review and critique of the literature

This paper reviews and critiques the literature on family engagement programmes in higher education, from the perspective of issues that may affect the design of programmes serving Native Hawaiian and Pacific Islander students and their families. While there is compelling research suggesting that increasing students' family members' engagement with higher education will benefit students, it is unclear whether the concept of family engagement as it is conceived in western educational contexts can be universally and unproblematically applied in Pacific contexts. Recommendations for best practices in family engagement programme design highlight communication efforts with parents that can be characterised as fundraising and ‘friendraising’, but do not address issues specific to the experiences of under‐represented groups in higher education. Drawing on the literature and experiences of indigenous and other under‐represented students, and incorporating insights from literature on decolonising methodologies, we present considerations for authentic and culturally responsive family engagement for Native Hawaiian and Pacific Islander students, families and communities.     

Landscape attributes and life history variability shape genetic structure of trout populations in a stream network

Spatial and temporal landscape patterns have long been recognized to influence biological processes, but these processes often operate at scales that are difficult to study by conventional means. Inferences from genetic markers can overcome some of these limitations. We used a landscape genetics approach to test hypotheses concerning landscape processes influencing the demography of Lahontan cutthroat trout in a complex stream network in the Great Basin desert of the western US. Predictions were tested with population- and individual-based analyses of microsatellite DNA variation, reflecting patterns of dispersal, population stability, and local effective population sizes. Complementary genetic inferences suggested samples from migratory corridors housed a mixture of fish from tributaries, as predicted based on assumed migratory life histories in those habitats. Also as predicted, populations presumed to have greater proportions of migratory fish or from physically connected, large, or high quality habitats had higher genetic variability and reduced genetic differentiation from other populations. Populations thought to contain largely non-migratory individuals generally showed the opposite pattern, suggesting behavioral isolation. Estimated effective sizes were small, and we identified significant and severe genetic bottlenecks in several populations that were isolated, recently founded, or that inhabit streams that desiccate frequently. Overall, this work suggested that Lahontan cutthroat trout populations in stream networks are affected by a combination of landscape and metapopulation processes. Results also demonstrated that genetic patterns can reveal unexpected processes, even within a system that is well studied from a conventional ecological perspective.     

Using an individual-based model to examine the roles of habitat fragmentation and behavior on predator–prey relationships in seagrass landscapes

Seagrasses, which form critical subtidal habitats for marine organisms worldwide, are fragmented via natural processes but are increasingly being fragmented and degraded by boating, fishing, and coastal development. We constructed an individual-based model to test how habitat fragmentation and loss influenced predator–prey interactions and cohort size for a group of settling juvenile blue crabs (Callinectes sapidus Rathbun) in seagrass landscapes. Using results from field studies suggesting that strong top-down processes influence the relationship between cannibalistic blue crab populations and seagrass landscape structure, we constructed a model in which prey (juvenile blue crabs) are eaten by mesopredators (larger blue crabs) which in turn are eaten by top-level predators (e.g., large fishes). In our model, we varied the following parameters within four increasingly fragmented seagrass landscapes to test for their relative effects on cohort size: juvenile blue crab (prey) predator avoidance response, hunting ability of mesopredators and predators, the presence of a top-level predator, and prey settlement routines. Generally, prey cohort size was maximized in the presence of top-level predators and when mesopredators and predators exhibited random searching behavior vs. directed hunting. Cohort size for stationary (tethered) prey was maximized in fragmented landscapes, which corresponds to results from field experiments, whereas mobile prey able to detect and avoid predators had higher survival in continuous landscapes. Prey settlement patterns had relatively small influences on cohort size. We conclude that the effects of seagrass fragmentation and loss on organisms such as blue crabs will depend heavily on behaviors of prey and predatory organisms and how these behaviors change with landscape structure.     

Developing a complementary framework for urban ecology

Cities are characterized by dynamic interactions between socio-economic and biophysical forces. Currently more than half of the global population reside in cities which influence the global biogeochemical cycles and climate change, substantially exacerbating pressures on urban pollution, water quality and food security, as well as operating costs for infrastructure development. Goods and services such as aesthetic values, water purification, nutrient recycling, and biological diversity, that urban ecosystems generate for the society, are critical to sustain. Urban planners are increasingly facing the considerable challenges of management issues for urban ecosystems. Poor understanding of the complementary roles of urban ecology in urban infrastructure, and the functioning of ecosystems and ecological resilience of a complex human-dominated landscape has impeded effective urban planning over time, resulting in social disharmony. Here a complementary framework for urban ecology is proposed, in which ecosystems interact with land use, architecture and urban design – “E-LAUD” – affecting ecosystem and human health, and building on the concept that land uses in urban green areas, road-strips, wetlands, ‘habitat islands’ and urban architecture could synergistically benefit when clustered together in different combinations of urban landscapes. It is proposed that incorporation of the E-LAUD framework in urban planning forms the context of a new interdisciplinary research programme on ecological resilience for urban ecosystems and helps promote ecosystem services.     

Assessment of swine farms in Greece in relation to the risk of exposure of pigs to Trichinella

Commission Regulation (EC) No. 2075/2005 of 5 December 2005 lays down detailed conditions for Trichinella-free farms. The objectives of the present study were: (1) to assess the current state of swine farms in Greece in relation to the risk of exposure of pigs to Trichinella as a first step towards certification of Trichinella-free farms in Greece and (2) to identify a profile and characteristics of swine farms and farmers which can be used to formulate appropriate measures to promote good production practices for reducing risk of exposure of pigs to Trichinella. A total of 70 swine farms were inspected using audit components similar to those used by the U.S. Trichinae Certification Programme. Only four farms (6%) complied with all the criteria used for assessing the good production practices for reducing risk of exposure of pigs to Trichinella. A common characteristic of these four farms was that they had a large size (>300 sows) and produced their own feed. The most common issues among the farms that did not meet audit criteria in the present study were related to proper rodent control and accessibility of other animals in the feed storage area and the facility. In addition, the predominant significant differentiating characteristic for the farms not meeting the criteria was their small (<150 sows) size, while for the farmers it was their low educational level. These characteristics, which are linked to poor infrastructure and reluctance for improvements, respectively, will be difficulties that must be dealt with in the promotion of good production practices for Trichinella-free farms in Greece.     

Pharmacokinetic profiles of meloxicam after single IV and PO administration in Bilgorajska geese

The purpose of this study was two-fold: I) to determine the pharmacokinetic profile of meloxicam (MLX) in geese after intravenous (IV) and oral (PO) administration and II) to assess tissue residues in muscle, heart, liver, lung, and kidney. Ten clinically normal female Bilgorajska geese were divided into two groups (treated, n = 8; control, n = 2). Group 1 underwent a 3-phase parallel study with a 1-week washout period. In phase I, animals received MLX (0.5 mg/kg) by IV administration; the blood was collected up to 48 hr. In phases II and III geese were treated orally at the same dosage for the collection of blood and tissue samples, respectively. Group 2 served as control. After the extraction procedure, a validated HPLC method with UV detection was used for plasma and organ analysis. The plasma concentrations were quantifiable up to 24 hr after both the administrations. The elimination phase of MLX from plasma was similar in both the administration groups. The clearance was slow (0.00975 L/hr*Kg), the volume of distribution small (0.0487 L/kg), and the IV half-life was 5.06 ± 2.32 hr. The average absolute PO bioavailability was 64.2 ± 24.0%. Residues of MLX were lower than the LOQ (0.1 µg/kg) in any tested tissue and at any collection time. The dosage used in this study achieved the plasma concentration, which provides analgesia in Hispaniolan Amazon parrots for 5 out of 24 hr after PO administration. MLX tissue concentrations were below the LOD of the assay in tissue (0.03 µg/ml). A more sensitive technique might be necessary to determine likely residue concentrations in tissue.