The decapod researcher’s guide to the galaxy of sex determination

The objective of this study was to assess the frequency of use of marine resources in recruitment of Southern Hemisphere native riverine fish Galaxias maculatus from rivers across a latitudinal gradient. To do this, we analysed the concentrations of δ³⁴S in vertebral column tissues from fish collected in ten Chilean river systems across latitudes 36°–47°S. The analyses of δ³⁴S signatures in these rivers suggest that the use of marine resources by riverine populations of G. maculatus in large river systems in Chile is variable, with marine resources playing a limited role in more northern large rivers, characterised by warmer temperatures and predictable flow regimes and floodplain inundations. This is in contrast to life histories described for G. maculatus in rivers from New Zealand and Australia, where riverine populations are believed to be characterised by an obligatory recruitment phase in marine environments. Recruitment of G. maculatus in Chilean large rivers appears to depend on their freshwater productivity driven by climate as well as both longitudinal (headwaters lakes-estuary) and lateral (main channel-floodplains) hydrologic connectivities.     

The role of herbivorous water birds in aquatic systems through interactions with aquatic macrophytes,with special reference to the Bewick’s Swan – Fennel Pondweed system

The role of aquatic macrophytes in stimulating biodiversity and maintaining clear waters is currently undisputed. The management of (eutrophic) shallow waters is therefore often directed at (re-)establishing macrophyte domination. In contrast, the role of water birds has long been considered of minor importance for the functioning of fresh water ecosystems. Indeed, in terms of biomass and production, water birds constitute only a minor part of these systems. However, water birds may graze heavily on water plants under certain circumstances, and the question arises whether herbivorous water birds have an important indirect effect on shallow fresh water systems. Mainly illustrated with the interaction between Bewick’s Swans and Fennel Pondweed, we present data on the role that water plants may play in the life of water birds and how water birds may impact water plants’ fitness in terms of survival, production, dispersal and competitive ability. It appears that water plants may be crucial for water birds during periods of high-energy requirements, such as migration. Despite the plants’ costs associated with water bird grazing, the interaction between water birds and water plants varies in nature from an apparent predator–prey relationship to a mutually beneficial interaction depending on the context and the perspective. For the case of the Bewick’s Swan–Fennel Pondweed interaction, regular bird grazing is sustainable and may actually favour the plant’s dispersal. Thus, Bewick’s Swans themselves may in fact play a crucial role in establishing and maintaining the Fennel Pondweed rich staging sites between the swans’ wintering and breeding grounds, which are vital for the swans’ successful migration.     

BioBanking: an environmental scientist’s view of the role of biodiversity banking offsets in conservation

Offsets, first formalised in the United States of America in the 1970s for wetland mitigation, are now widely used globally with the aim to mitigate loss of biodiversity due to development. Embracing biodiversity offsets is one method of governments to meet their commitments under the Millennium Development Goals and the Convention on Biological Diversity. Resource extraction companies see them as a method of gaining access to land, while the community may perceive them as a way of enhancing environmental outcomes. In New South Wales, Australia, BioBanking legislation was introduced in late 2006 with the aim of ‘no net loss’ of biodiversity associated with development, particularly expanding urban and coastal development. The strengths of the legislation are that it aims to enhance threatened species conservation, and raise the profile of conservation of threatened species and habitats. Weaknesses include (1) the narrowness of the definition of biodiversity; (2) the concepts are based on a flawed logic and immature, imprecise and complex science which results in difficulties in determining biodiversity values; (3) likely problems with management and compliance; and (4) an overall lack of resources for implementation and long-term monitoring. It is concluded that the legislation is a concerted effort to deal with biodiversity loss, however, stakeholders have concerns with the process, and it is unworkable with the complexity of such ecosystems (compared for example to carbon credit trading), and underdeveloped disciplines such as restoration biology and ecology. Despite these criticisms, there is a need for all stakeholders to work to improve the outcomes.     

Life cycle abbreviation in the trematode Coitocaecum parvum: can parasites adjust to variable conditions?

The complex life cycles of parasites are thought to have evolved from simple one-host cycles by incorporating new hosts. Nevertheless, complex developmental routes present parasites with a sequence of highly unlikely transmission events in order to complete their life cycles. Some trematodes like Coitocaecum parvum use facultative life cycle abbreviation to counter the odds of trophic transmission to the definitive host. Parasites adopting life cycle truncation possess the ability to reproduce within their intermediate host, using progenesis, without the need to reach the definitive host. Usually, both abbreviated and normal life cycles are observed in the same population of parasites. Here, we demonstrate experimentally that C. parvum can modulate its development in its amphipod intermediate host and adopt either the abbreviated or the normal life cycle depending on current transmission opportunities or the degree of intra-host competition among individual parasites. In the presence of cues from its predatory definitive host, the parasite is significantly less likely to adopt progenesis than in the absence of such cues. An intermediate response is obtained when the parasites are exposed to cues from non-host predators. The adoption of progenesis is less likely, however, when two parasites share the resource-limited intermediate host. These results show that parasites with complex developmental routes have transmission strategies and perception abilities that are more sophisticated than previously thought.     

The C/A polymorphism in intron 11 of the XPC gene plays a crucial role in the modulation of an individual’s susceptibility to sporadic colorectal cancer

Epidemiological data show that colorectal cancer (CRC) is the second most frequent malignancy worldwide. The involvement of “minor impact genes” such as XME and DNA-repair genes in the etiology of sporadic cancer has been postulated by other authors. We focused on analyzing polymorphisms in DNA-repair genes in CRC. We considered the following genes involved in DNA-repair pathways: base excision repair (OGG1 Ser326Cys, XRCC1 Trp194Arg and Arg399Gln); nucleotide excision repair [XPA (−4)G/A, XPC C/A (i11) and A33512C (Lys939Gln), XPD Asp312Asn and A18911C (Lys751Gln), XPF Arg415Gln, XPG Asp1104His, ERCC1 C118T]; homologous recombination repair [NBS1 Glu185Gln, Rad51 135G/C, XRCC3 C18067 (Thr241Met)]. The study group consisted of 133 patients diagnosed with sporadic CRC, while the control group was composed of 100 age-matched non-cancer volunteers. Genotyping was performed by PCR and PCR-RFLP. Fisher’s exact test with a Bonferroni correction for multiple testing was used. We found that: (i) XPC C/A (i11) heterozygous variant is associated with increased risk of CRC [OR is 2.07 (95% CI 1.1391, 3.7782) P = 0.038], (ii) XPD A18911C (Lys751Gln) is associated with decreased risk of CRC [OR = 0.4497, (95% CI 0.2215, 0.9131) P = 0.031] for an individual with at least one A allele at this locus. (1) The XPC C/A (i11) genotype is associated with an increased risk of sporadic colorectal cancer. (2) The NER pathway has been highlighted in our study, as a most important in modulation of individual susceptibility to sCRC.     

The role of Apodemus mice and Microtus voles in the diet of the Tengmalm’s owl in Central Europe

Based on a long-term dataset (1999–2010), we investigated how the availability of main prey affects the breeding density and food ecology of the Tengmalm’s owl (Aegolius funereus) in the Czech Republic. In particular, we assessed the role of Microtus voles and Apodemus mice in the diet, based on the main predictions of the optimal diet theory that the diet composition depends on the availability of the main prey. We found that (i) the Tengmalm’s owl exhibited no numerical response to the availability of Microtus voles and Apodemus mice in the field; (ii) the availability of Apodemus mice in the field positively affected their proportion in the diet (26 %), and despite a high proportion of Microtus voles in the owls’ diet (47 %), no relationship was found between their availability in the field and proportion in the diet; (iii) the proportion of Apodemus mice was negatively correlated to the proportion of Microtus voles, Sorex shrews and birds in the diet, but no similar relationship was detected for Microtus voles; (iv) the reproductive output of Tengmalm’s owls was positively correlated to the proportion of Apodemus mice in the diet, as well as to Apodemus mice and Microtus vole availability in the field; and (v) diet diversity and diet overlap were not significantly affected by the abundance of Apodemus mice and Microtus voles. Therefore, the validity of these main optimal diet theory predictions was not confirmed, especially for Microtus vole prey, due to an opportunistic choice between Apodemus mice and Microtus voles. We suggest that the reproductive output of nocturnal raptors in Central Europe may be less dependent on Microtus vole supply than that of their northern counterparts.     

The role of ecotourism in conservation: panacea or Pandora’s box?

Does ecotourism contribute towards conservation of threatened species and habitats or is it just a marketing ploy of the tourism industry? Using 251 case studies on ecotourism from the literature, I looked at the distribution of case studies over continents, habitats and flagship species types and what factors influenced whether an ecotourism regime was perceived as ecologically sustainable by authors. Over 50% of ecotourism case studies were reported from Africa and Central America. The overall distribution of ecotourism case studies did not reflect vertebrate endemism, nor overall tourism distribution in terms of tourist numbers and receipts. There were significant differences between continents and habitats with regard to the proportion of sustainable case studies: ecotourism is perceived to be less sustainable in South America and Asia, and in island and mountain habitats. The type of flagship species also influenced whether ecotourism was classified as sustainable or not: ecotourism with no flagship species was rarely classified as sustainable while charismatic bird and mammal species were associated with a higher probability of sustainability. In a multivariate analysis, flagship species type and local community involvement were important predictors of sustainability in ecotourism. Detailed a priori planning, local involvement and control measures were perceived by authors of case studies to increase the success of ecotourism in conservation. They also perceived that ecotourism can only be an effective conservation tool under certain conditions. If these are met, the evidence indicates that ecotourism can make a contribution to conservation.     

The functional importance of parasites in animal communities: many roles at many levels?

Past research on parasites and community ecology has focussed on two distinct levels of the overall community. First, it has been shown that parasites can have a role in structuring host communities. They can have differential effects on the different hosts that they exploit, they can directly debilitate a host that itself is a key structuring force in the community, or they can indirectly alter the phenotype of their host and change the importance of the host for the community. Second, certain parasite species can be important in shaping parasite communities. Dominant parasite species can directly compete with other parasite species inside the host and reduce their abundance to some extent, and parasites that alter host phenotype can indirectly make the host more or less suitable for other parasite species. The possibility that a parasite species simultaneously affects the structure of all levels of the overall community, i.e. the parasite community and the community of free-living animals, is never considered. Given the many direct and indirect ways in which a parasite species can modulate the abundance of other species, it is conceivable that some parasite species have functionally important roles in a community, and that their removal would change the relative composition of the whole community. An example from a soft-sediment intertidal community is used to illustrate how the subtle, indirect effects of a parasite species on non-host species can be very important to the structure of the overall community. Future community studies addressing the many potential influences of parasites will no doubt identify other functionally important parasite species that serve to maintain biodiversity.     

The role of the NTPDase enzyme family in parasites: what do we know, and where to from here?

Nucleoside triphosphate diphosphohydrolases (NTPDases, GDA1_CD39 protein superfamily) play a diverse range of roles in a number of eukaryotic organisms. In humans NTPDases function in regulating the inflammatory and immune responses, control of vascular haemostasis and purine salvage. In yeast NTPDases are thought to function primarily in the Golgi, crucially involved in nucleotide sugar transport into the Golgi apparatus and subsequent protein glycosylation. Although rare in bacteria, in Legionella pneumophila secreted NTPDases function as virulence factors. In the last 2 decades it has become clear that a large number of parasites encode putative NTPDases, and the functions of a number of these have been investigated. In this review, the available evidence for NTPDases in parasites and the role of these NTPDases is summarized and discussed. Furthermore, the processes by which NTPDases could function in pathogenesis, purine salvage, thromboregulation, inflammation and glycoconjugate formation are considered, and the data supporting such putative roles reviewed. Potential future research directions to further clarify the role and importance of NTPDases in parasites are proposed. An attempt is also made to clarify the nomenclature used in the parasite field for the GDA1_CD39 protein superfamily, and a uniform system suggested.     

The use of cluster and discriminant analysis in the investigations of the role of trace metals in the pathogenesis of Parkinson’s disease

X-ray fluorescence microscopy was applied for two-dimensional elemental analysis of substantia nigra (SN) tissue. The samples representing Parkinson’s disease (PD) and control cases were examined at HASYLAB beamline L and at ESRF beamline ID22. Two-dimensional mapping of P, S, Cl, K, Ca, Fe, Cu, Zn, Se and Br was done with the spatial resolution of 15 and 5 μm. The masses per unit area of elements in neuromelanin reach nerve cells of SN were determined.The elemental data were processed using two multivariate techniques, namely cluster and discriminant analysis. The statistical methods were used for data reduction, both unsupervised and supervised classification as well as for the creation of a model that would simplify case identification based on the elemental analysis of SN tissue. The results of cluster analysis confirmed the statistical significance of the differences in elemental composition of PD and control SN nerve cells. Based on the results of discriminant analysis, the elements (P, Cl, Fe, Cu and Zn) that played the greatest role in the process of differentiation between neurons from examined groups were determined.     

The Role of the Sympathoadrenomedullary System in the Formation of Pilot’s Adaptation to Flight Loads

The objective of this study was to evaluate the functions of the sympathoadrenomedullary system and the related psychophysiological reactions of pilots, depending on flying hours on a highly maneuverable aircraft. The study involved 78 volunteer pilots (41 high-maneuverability pilots and 37 bomber and transport aviation pilots). A set of methods was chosen with the possibility of their use according to the principle of comprehensive evaluation of the body functional state under flight loads taken into account. Our results indicate that highly maneuverable aircraft piloting induces a significant activation of the sympathoadrenomedullary system in pilots, compared to bombing and transport aircrafts. This is particularly common to young pilots with the total flying time of less than 1000 h. It has been recorded that changes in adaptation to the effect of flight factors on the body develop with age and flight experience.     

Reactions to Media Violence: It’s in the Brain of the Beholder

Media portraying violence is part of daily exposures. The extent to which violent media exposure impacts brain and behavior has been debated. Yet there is not enough experimental data to inform this debate. We hypothesize that reaction to violent media is critically dependent on personality/trait differences between viewers, where those with the propensity for physical assault will respond to the media differently than controls. The source of the variability, we further hypothesize, is reflected in autonomic response and brain functioning that differentiate those with aggression tendencies from others. To test this hypothesis we pre-selected a group of aggressive individuals and non-aggressive controls from the normal healthy population; we documented brain, blood-pressure, and behavioral responses during resting baseline and while the groups were watching media violence and emotional media that did not portray violence. Positron Emission Tomography was used with [¹⁸F]fluoro-deoxyglucose (FDG) to image brain metabolic activity, a marker of brain function, during rest and during film viewing while blood-pressure and mood ratings were intermittently collected. Results pointed to robust resting baseline differences between groups. Aggressive individuals had lower relative glucose metabolism in the medial orbitofrontal cortex correlating with poor self-control and greater glucose metabolism in other regions of the default-mode network (DMN) where precuneus correlated with negative emotionality. These brain results were similar while watching the violent media, during which aggressive viewers reported being more Inspired and Determined and less Upset and Nervous, and also showed a progressive decline in systolic blood-pressure compared to controls. Furthermore, the blood-pressure and brain activation in orbitofrontal cortex and precuneus were differentially coupled between the groups. These results demonstrate that individual differences in trait aggression strongly couple with brain, behavioral, and autonomic reactivity to media violence which should factor into debates about the impact of media violence on the public.     

Biomedical engineer’s guide to the clinical aspects of intensive care mechanical ventilation

Background

Mechanical ventilation is an essential therapy to support critically ill respiratory failure patients. Current standards of care consist of generalised approaches, such as the use of positive end expiratory pressure to inspired oxygen fraction (PEEP–FiO₂) tables, which fail to account for the inter- and intra-patient variability between and within patients. The benefits of higher or lower tidal volume, PEEP, and other settings are highly debated and no consensus has been reached. Moreover, clinicians implicitly account for patient-specific factors such as disease condition and progression as they manually titrate ventilator settings. Hence, care is highly variable and potentially often non-optimal. These conditions create a situation that could benefit greatly from an engineered approach. The overall goal is a review of ventilation that is accessible to both clinicians and engineers, to bridge the divide between the two fields and enable collaboration to improve patient care and outcomes. This review does not take the form of a typical systematic review. Instead, it defines the standard terminology and introduces key clinical and biomedical measurements before introducing the key clinical studies and their influence in clinical practice which in turn flows into the needs and requirements around how biomedical engineering research can play a role in improving care. Given the significant clinical research to date and its impact on this complex area of care, this review thus provides a tutorial introduction around the review of the state of the art relevant to a biomedical engineering perspective.

Discussion

This review presents the significant clinical aspects and variables of ventilation management, the potential risks associated with suboptimal ventilation management, and a review of the major recent attempts to improve ventilation in the context of these variables. The unique aspect of this review is a focus on these key elements relevant to engineering new approaches. In particular, the need for ventilation strategies which consider, and directly account for, the significant differences in patient condition, disease etiology, and progression within patients is demonstrated with the subsequent requirement for optimal ventilation strategies to titrate for patient- and time-specific conditions.

Conclusion

Engineered, protective lung strategies that can directly account for and manage inter- and intra-patient variability thus offer great potential to improve both individual care, as well as cohort clinical outcomes.

     

The role of dopamine oxidation in mitochondrial dysfunction: implications for Parkinson’s disease

The etiology of sporadic Parkinson’s disease (PD) is unknown, although mitochondrial dysfunction and oxidative stress have been implicated in the mechanisms associated with PD pathogenesis. Dopamine (DA) neurons of the substantia nigra pars compacta have been shown to degenerate to a greater extent in PD than other neurons suggesting the possibility that DA itself may be contributing to the neurodegenerative process. This review discusses our work on the effects of DA oxidation and reactive DA quinones on mitochondrial function and protein modification and the potential for exacerbating toxicity associated with mitochondrial dysfunction in PD.     

Out-of-Africa,human-mediated dispersal of the common cat flea,Ctenocephalides felis: The hitchhiker’s guide to world domination

The cat flea (Ctenocephalides felis) is the most common parasite of domestic cats and dogs worldwide. Due to the morphological ambiguity of C. felis and a lack of — particularly largescale — phylogenetic data, we do not know whether global C. felis populations are morphologically and genetically conserved, or whether human-mediated migration of domestic cats and dogs has resulted in homogenous global populations. To determine the ancestral origin of the species and to understand the level of global pervasion of the cat flea and related taxa, our study aimed to document the distribution and phylogenetic relationships of Ctenocephalides fleas found on cats and dogs worldwide. We investigated the potential drivers behind the establishment of regional cat flea populations using a global collection of fleas from cats and dogs across six continents. We morphologically and molecularly evaluated six out of the 14 known taxa comprising genus Ctenocephalides, including the four original C. felis subspecies (Ctenocephalides felis felis, Ctenocephalides felis strongylus, Ctenocephalides felis orientis and Ctenocephalides felis damarensis), the cosmopolitan species Ctenocephalides canis and the African species Ctenocephalides connatus. We confirm the ubiquity of the cat flea, representing 85% of all fleas collected (4357/5123). Using a multigene approach combining two mitochondrial (cox1 and cox2) and two nuclear (Histone H3 and EF-1α) gene markers, as well as a cox1 survey of 516 fleas across 56 countries, we demonstrate out-of-Africa origins for the genus Ctenocephalides and high levels of genetic diversity within C. felis. We define four bioclimatically limited C. felis clusters (Temperate, Tropical I, Tropical II and African) using maximum entropy modelling. This study defines the global distribution, African origin and phylogenetic relationships of global Ctenocephalides fleas, whilst resolving the taxonomy of the C. felis subspecies and related taxa. We show that humans have inadvertently precipitated the expansion of C. felis throughout the world, promoting diverse population structure and bioclimatic plasticity. By demonstrating the link between the global cat flea communities and their affinity for specific bioclimatic niches, we reveal the drivers behind the establishment and success of the cat flea as a global parasite.