Excitotoxic Stimulation of Brain Microslices as an In vitro Model of Stroke

Examining molecular mechanisms involved in neuropathological conditions, such as ischemic stroke, can be difficult when using whole animal systems. As such, primary or ''neuronal-like'' cell culture systems are commonly utilized. While these systems are relatively easy to work with, and are useful model systems in which various functional outcomes (such as cell death) can be readily quantified, the examined outcomes and pathways in cultured immature neurons (such as excitotoxicity-mediated cell death pathways) are not necessarily the same as those observed in mature brain, or in intact tissue. Therefore, there is the need to develop models in which cellular mechanisms in mature neural tissue can be examined. We have developed an in vitro technique that can be used to investigate a variety of molecular pathways in intact nervous tissue. The technique described herein utilizes rat cortical tissue, but this technique can be adapted to use tissue from a variety of species (such as mouse, rabbit, guinea pig, and chicken) or brain regions (for example, hippocampus, striatum, etc.). Additionally, a variety of stimulations/treatments can be used (for example, excitotoxic, administration of inhibitors, etc.). In conclusion, the brain slice model described herein can be used to examine a variety of molecular mechanisms involved in excitotoxicity-mediated brain injury.     

Genetic conflict,kin and the origins of novel genetic systems

Genetic conflict may have played an important role in the evolution of novel genetic systems. The ancestral system of eumendelian genetics is highly symmetrical. Those derived from it (e.g. thelytokous parthenogenesis, haplodiploidy and parent-specific allele expression) are more asymmetrical in the genetic role played by maternal versus paternal alleles. These asymmetries may have arisen from maternal–paternal genetic conflict, or cytonuclear conflict, or from an interaction between them. Asymmetric genetic systems are much more common in terrestrial and freshwater taxa than in marine taxa. We suggest three reasons for this, based on the relative inhospitability of terrestrial environments to three types of organism: (i) pathogens—departure from the marine realm meant escape from many pathogens and parasites, reducing the need for sexual reproduction; (ii) symbionts—symbionts are no more important in the terrestrial realm than the marine realm but are more likely to be obligately intracellular and vertically transmitted, making them more likely to disrupt their host''s genetic systems; (iii) Gametes and embryos—because neither gametes nor embryos can be shed into air as easily as into seawater, the mother''s body is a more important environment for both types of organisms in the terrestrial realm than in the marine realm. This environment of asymmetric kinship (with neighbours more closely related by maternal alleles than by paternal alleles) may have helped to drive asymmetries in expression and transmission.     

Bacterial Lifestyle in a Deep-sea Hydrothermal Vent Chimney Revealed by the Genome Sequence of the Thermophilic Bacterium Deferribacter desulfuricans SSM1

The complete genome sequence of the thermophilic sulphur-reducing bacterium, Deferribacter desulfuricans SMM1, isolated from a hydrothermal vent chimney has been determined. The genome comprises a single circular chromosome of 2 234 389 bp and a megaplasmid of 308 544 bp. Many genes encoded in the genome are most similar to the genes of sulphur- or sulphate-reducing bacterial species within Deltaproteobacteria. The reconstructed central metabolisms showed a heterotrophic lifestyle primarily driven by C1 to C3 organics, e.g. formate, acetate, and pyruvate, and also suggested that the inability of autotrophy via a reductive tricarboxylic acid cycle may be due to the lack of ATP-dependent citrate lyase. In addition, the genome encodes numerous genes for chemoreceptors, chemotaxis-like systems, and signal transduction machineries. These signalling networks may be linked to this bacterium''s versatile energy metabolisms and may provide ecophysiological advantages for D. desulfuricans SSM1 thriving in the physically and chemically fluctuating environments near hydrothermal vents. This is the first genome sequence from the phylum Deferribacteres.     

Competitive interactions in Escherichia coli populations: the role of bacteriocins

Explaining the coexistence of competing species is a major challenge in community ecology. In bacterial systems, competition is often driven by the production of bacteriocins, which are narrow-spectrum proteinaceous toxins that serve to kill closely related species, providing the producer better access to limited resources. Bacteriocin producers have been shown to competitively exclude sensitive, nonproducing strains. However, the dynamics between bacteriocin producers, each lethal to its competitor, are largely unknown. In this study, we used in vitro, in vivo and in silico models to study competitive interactions between bacteriocin producers. Two Escherichia coli strains were generated, each carrying a DNA-degrading bacteriocin (colicins E2 and E7). Using reporter-gene assays, we showed that each DNase bacteriocin is not only lethal to its opponent but, at lower doses, can also induce the expression of its opponent''s toxin. In a well-mixed habitat, the E2 producer outcompeted its adversary; however, in structured environments (on plates or in mice colons), the two producers coexisted in a spatially ‘frozen'' pattern. Coexistence occurred when the producers were initiated with a clumped spatial distribution. This suggests that a ‘clump'' of each producer can block invasion of the other producer. Agent-based simulation of bacteriocin-mediated competition further showed that mutual exclusion in a structured environment is a relatively robust result. These models imply that colicin-mediated colicin induction enables producers to successfully compete and defend their niche against invaders. This suggests that localized interactions between producers of DNA-degrading toxins can lead to stable coexistence of heterogeneously distributed strains within the bacterial community and to the maintenance of diversity.     

Redundancy or specificity? The role of the CDK Pho85 in cell cycle control

It is generally accepted that progression through the eukaryotic cell cycle is driven by cyclin-dependent kinases (CDKs), which are regulated by interaction with oscillatory expressed proteins called cyclins. CDKs may be separated into 2 categories: essential and non-essential. Understandably, more attention has been focused on essential CDKs because they are shown to control cell cycle progression to a greater degree. After clearly determining the basic and “core” mechanisms of essential CDKs, several questions arise. What role do non-essential CDKs play? Are these CDKs functionally redundant and do they serve as a mere backup? Or might they be responsible for some accessory tasks in cell cycle progression or control? In the present review we will try to answer these questions based on recent findings on the involvement of non-essential CDKs in cell cycle progression. We will analyse the most recent information with regard to these questions in the yeast Saccharomyces cerevisiae, a well-established eukaryotic model, and in its unique non-essential CDK involved in the cell cycle, Pho85. We will also briefly extend our discussion to higher eukaryotic systems.     

Interactions between Meloidogyne incognita,M. hapla,and Pratylenchus brachyurus in Tobacco

In a greenhouse pot experiment on the pathogenicity and interactions of Meloidogyne incognita, M. hapla and Pratylenchus brachyurus on four cultivars o f tobacco the cultivars ''Hicks'' and ''NC 2326'' were susceptible to each nematode and "NC 95'' and ''NC 2512'' resistant only to M. incognita.Mean heights of susceptible plants were depressed but fresh weight of tops did not differ significantly. Meloidogyne spp. increased fresh weight of susceptible (but not the resistant) roots.Reproduction of M. incognita was decreased in the presence of P. brachyurus in one case. M. hapla reproduction was less with either of the other nematodes in five out of eight cases. In 12 combinations involving P. brachyurus, reproduction of this species was depressed in seven, not affected in four and increased in one.Mechanisms involved in associative interactions were not identified but appeared to be indirect and to involve individual host-nematode responses.     

Clues to γ-secretase,huntingtin and Hirano body normal function using the model organism Dictyostelium discoideum

Many neurodegenerative disorders, although related by their destruction of brain function, display remarkable cellular and/or regional pathogenic specificity likely due to a deregulated functionality of the mutant protein. However, neurodegenerative disease genes, for example huntingtin (HTT), the ataxins, the presenilins (PSEN1/PSEN2) are not simply localized to neurons but are ubiquitously expressed throughout peripheral tissues; it is therefore paramount to properly understand the earliest precipitating events leading to neuronal pathogenesis to develop effective long-term therapies. This means, in no unequivocal terms, it is crucial to understand the gene''s normal function. Unfortunately, many genes are often essential for embryogenesis which precludes their study in whole organisms. This is true for HTT, the β-amyloid precursor protein (APP) and presenilins, responsible for early onset Alzheimer''s disease (AD). To better understand neurological disease in humans, many lower and higher eukaryotic models have been established. So the question arises: how reasonable is the use of organisms to study neurological disorders when the model of choice does not contain neurons? Here we will review the surprising, and novel emerging use of the model organism Dictyostelium discoideum, a species of soil-living amoeba, as a valuable biomedical tool to study the normal function of neurodegenerative genes. Historically, the evidence on the usefulness of simple organisms to understand the etiology of cellular pathology cannot be denied. But using an organism without a central nervous system to understand diseases of the brain? We will first introduce the life cycle of Dictyostelium, the presence of many disease genes in the genome and how it has provided unique opportunities to identify mechanisms of disease involving actin pathologies, mitochondrial disease, human lysosomal and trafficking disorders and host-pathogen interactions. Secondly, I will highlight recent studies on the function of HTT, presenilin γ-secretase and Hirano bodies conducted in Dictyostelium. I will then outline the limitations and future directions in using Dictyostelium to study disease, and finally conclude that given the evolutionary conservation of genes between Dictyostelium and humans and the organisms'' genetic tractability, that this system provides a fertile environment for discovering normal gene function related to neurodegeneration and will permit translational studies in higher systems.     

Challenge of investigating biologically relevant functions of virulence factors in bacterial pathogens

Recent innovations have increased enormously the opportunities for investigating the molecular basis of bacterial pathogenicity, including the availability of whole-genome sequences, techniques for identifying key virulence genes, and the use of microarrays and proteomics. These methods should provide powerful tools for analysing the patterns of gene expression and function required for investigating host-microbe interactions in vivo. But, the challenge is exacting. Pathogenicity is a complex phenotype and the reductionist approach does not adequately address the eclectic and variable outcomes of host-microbe interactions, including evolutionary dynamics and ecological factors. There are difficulties in distinguishing bacterial ''virulence'' factors from the many determinants that are permissive for pathogenicity, for example those promoting general fitness. A further practical problem for some of the major bacterial pathogens is that there are no satisfactory animal models or experimental assays that adequately reflect the infection under investigation. In this review, we give a personal perspective on the challenge of characterizing how bacterial pathogens behave in vivo and discuss some of the methods that might be most relevant for understanding the molecular basis of the diseases for which they are responsible. Despite the powerful genomic, molecular, cellular and structural technologies available to us, we are still struggling to come to grips with the question of ''What is a pathogen?''     

Bacterial disease management: challenges,experience, innovation and future prospects

Plant diseases caused by bacterial pathogens place major constraints on crop production and cause significant annual losses on a global scale. The attainment of consistent effective management of these diseases can be extremely difficult, and management potential is often affected by grower reliance on highly disease‐susceptible cultivars because of consumer preferences, and by environmental conditions favouring pathogen development. New and emerging bacterial disease problems (e.g. zebra chip of potato) and established problems in new geographical regions (e.g. bacterial canker of kiwifruit in New Zealand) grab the headlines, but the list of bacterial disease problems with few effective management options is long. The ever‐increasing global human population requires the continued stable production of a safe food supply with greater yields because of the shrinking areas of arable land. One major facet in the maintenance of the sustainability of crop production systems with predictable yields involves the identification and deployment of sustainable disease management solutions for bacterial diseases. In addition, the identification of novel management tactics has also come to the fore because of the increasing evolution of resistance to existing bactericides. A number of central research foci, involving basic research to identify critical pathogen targets for control, novel methodologies and methods of delivery, are emerging that will provide a strong basis for bacterial disease management into the future.

• Near‐term solutions are desperately needed. Are there replacement materials for existing bactericides that can provide effective disease management under field conditions?
• Experience should inform the future. With prior knowledge of bactericide resistance issues evolving in pathogens, how will this affect the deployment of newer compounds and biological controls?
• Knowledge is critical. A comprehensive understanding of bacterial pathosystems is required to not only identify optimal targets in the pathogens, but also optimal seasonal timings for deployment.
• Host resistance to effectors must be exploited, carefully and correctly. Are there other candidate genes that could be targeted in transgenic approaches? How can new technologies (CRISPR, TALEN, etc.) be most effectively used to add sustainable disease resistance to existing commercially desirable plant cultivars?
• We need an insider's perspective on the management of systemic pathogens. In addition to host resistance or reduced sensitivity, are there other methods that can be used to target these pathogen groups?
• Biological systems are variable. Can biological control strategies be improved for bacterial disease management and be made more predictable in function?

The answers to the research foci outlined above are not all available, as will become apparent in this article, but we are heading in the right direction. In this article, we summarize the contributions from past experiences in bacterial disease management, and also describe how advances in bacterial genetics, genomics and host–pathogen interactions are informing novel strategies in virulence inhibition and in host resistance. We also outline potential innovations that could be exploited as the pressures to maximize a safe and productive food supply continue to become more numerous and more complex.     

Do Coaches Perceive Themselves as Influential on Physical Activity for Girls in Organised Youth Sport?

Participation in organised youth sports (OYS) has been recommended as an opportunity to increase young peoples'' physical activity (PA) levels. While coaches can potentially influence athletes'' PA levels, what has not been explored is the question; do coaches perceive themselves as influential on PA for girls in OYS? Participants were 30 coaches of girls OYS teams aged 9–17 years in the Greater Sydney Metropolitan Area, Australia. Participants took part in a semi-structured interview that lasted approximately 30 minutes. They responded to questions regarding their perceived role as coaches, their perceptions of themselves as role models for PA, their views on their athletes'' current PA levels, their opinions on improving their athletes'' PA levels, and their perceived challenges as coaches in OYS. Many coaches considered themselves role models for PA due to their own involvement in organised sports. Coaches felt that they were conscious of girls'' PA levels during training and could accurately gauge how active girls were. Coaches perceived their training sessions to provide sufficient PA and thus, did not feel the need to try to increase PA during training. Many coaches were cautious about conducting training sessions where the PA intensity was high for prolonged periods because they believed that it could potentially result in dropout from OYS. Coaches'' perceived time commitment to OYS, variability of skill/experience amongst girls, and poor parental support as major challenges they experienced in OYS. This study provided a unique insight from the perspective of coaches in OYS. Most coaches felt that they had the potential to influence PA for girls in OYS; however, coaches may underestimate or not fully realise the impact they can have on the girls they coach. Future research should focus on educating coaches to capitalise on the opportunity they have to promote PA through OYS.     

Multidecadal changes in functional diversity lag behind the recovery of taxonomic diversity

While there has been increasing interest in how taxonomic diversity is changing over time, less is known about how long‐term taxonomic changes may affect ecosystem functioning and resilience. Exploring long‐term patterns of functional diversity can provide key insights into the capacity of a community to carry out ecological processes and the redundancy of species’ roles. We focus on a protected freshwater system located in a national park in southeast Germany. We use a high‐resolution benthic macroinvertebrate dataset spanning 32 years (1983–2014) and test whether changes in functional diversity are reflected in taxonomic diversity using a multidimensional trait‐based approach and regression analyses. Specifically, we asked: (i) How has functional diversity changed over time? (ii) How functionally distinct are the community''s taxa? (iii) Are changes in functional diversity concurrent with taxonomic diversity? And (iv) what is the extent of community functional redundancy? Resultant from acidification mitigation, macroinvertebrate taxonomic diversity increased over the study period. Recovery of functional diversity was less pronounced, lagging behind responses of taxonomic diversity. Over multidecadal timescales, the macroinvertebrate community has become more homogenous with a high degree of functional redundancy, despite being isolated from direct anthropogenic activity. While taxonomic diversity increased over time, functional diversity has yet to catch up. These results demonstrate that anthropogenic pressures can remain a threat to biotic communities even in protected areas. The differences in taxonomic and functional recovery processes highlight the need to incorporate functional traits in assessments of biodiversity responses to global change.     

Social benefits of non-kin food sharing by female vampire bats

Regurgitations of blood among vampire bats appear to benefit both direct and indirect fitness. To maximize inclusive fitness, reciprocal food sharing should occur among close kin. Why then do females with kin roost-mates help non-kin? We tested the hypothesis that helping non-kin increases a bat''s success at obtaining future donations by expanding its network of potential donors. On six occasions, we individually fasted 14 adult females and measured donations from 28 possible donors. Each female was fasted before, during and after a treatment period, when we prevented donations from past donors (including 10 close relatives) by simultaneously fasting or removing them. This experiment was designed to detect partner switching and yielded three main results. First, females received less food when we prevented donations from a past donor versus a control bat. Donors within a group are therefore not interchangeable. Second, the treatment increased the variance in donors'' contributions to food received by subjects, suggesting the possibility of alternative responses to a partner''s inability to reciprocate. Finally, bats that fed more non-kin in previous years had more donors and received more food during the treatment. These results indicate that a bat can expand its network of possible donors by helping non-kin.     

Global positioning system and associated technologies in animal behaviour and ecological research

Biologists can equip animals with global positioning system (GPS) technology to obtain accurate (less than or equal to 30 m) locations that can be combined with sensor data to study animal behaviour and ecology. We provide the background of GPS techniques that have been used to gather data for wildlife studies. We review how GPS has been integrated into functional systems with data storage, data transfer, power supplies, packaging and sensor technologies to collect temperature, activity, proximity and mortality data from terrestrial species and birds. GPS ‘rapid fixing’ technologies combined with sensors provide location, dive frequency and duration profiles, and underwater acoustic information for the study of marine species. We examine how these rapid fixing technologies may be applied to terrestrial and avian applications. We discuss positional data quality and the capability for high-frequency sampling associated with GPS locations. We present alternatives for storing and retrieving data by using dataloggers (biologging), radio-frequency download systems (e.g. very high frequency, spread spectrum), integration of GPS with other satellite systems (e.g. Argos, Globalstar) and potential new data recovery technologies (e.g. network nodes). GPS is one component among many rapidly evolving technologies. Therefore, we recommend that users and suppliers interact to ensure the availability of appropriate equipment to meet animal research objectives.     

An Imported Case of Cystic Echinococcosis in the Liver

A 25-year-old Uzbek male presented with right upper abdominal pain for 20 days. On radiologic studies, a huge cystic mass was noticed in the right liver which was suspected as parasitic. The patient received right hepatic segmentectomy (segment 7), and the surgically resected mass was confirmed as cystic echinococcosis (CE), measuring 10.5 cm in its diameter. The inner surface of the cyst was bile-stained. The patient was discharged on the 8th hospital day, and was rechecked 6 months after the surgical intervention without any evidence of recurrence. The present report describes findings of an imported case of CE which represented ultrasound images of the ''ball of wool''.     

Selection Against Heterodera glycines Males by Soybean Lines with Genes for Resistance

Soybeans with genes for resistance select against Heterodera glycines with the corresponding genes for avirulence. There may be a differential effect of sex with some specific gene interactions, which would influence the magnitude of gene frequency changes. No effect on H. glycines males was detected with one selected nematode population and the resistant soybean line PI88788. The selective effect of PI89772 against male nematodes was greater with two inbred nematode populations than with one selected (on PI88788) population, presumably due to differences in H. glycines gene frequencies. ''Peking'' also had few males with the one inbred nematode population, whereas Forrest and ''Pickett 71'' had intermediate numbers. Apparently Forrest and Pickett 71 did not get all the Peking genes for resistance that affect male as well as female nematode development. Other H. glycines-soybean genes stop only females, since there were few or no cysts, except on the susceptible soybean Williams. The number of males'' phenotype will help identify specific genes in both organisms.     

What Are Imprinted Genes Doing in the Brain?

As evidence for the existence of brain?expressed imprinted genes accumulates, we need to address exactly what they are doing in this tissue, especially in terms of organizational themes and the major challenges posed by reconciling imprinted gene action in brain with current evolutionary theories attempting to explain the origin and maintenance of genomic imprinting. We are at the beginning of this endeavor and much work remains to be done but already it is clear that imprinted genes have the potential to influence diverse behavioral processes via multiple brain mechanisms. There are also grounds to believe that imprinting may contribute to risk of mental and neurological disease. As well as being a source of basic information about imprinted genes in the brain (e.g., via the newly established website, www.bgg.cardiff.ac.uk/imprinted_tables/index.html), we have used this chapter to identify and focus on a number of key questions. How are brain?expressed imprinted genes organized at the molecular and cellular levels? To what extent does imprinted action depend on neurodevelopmental mechanisms? Do imprinted gene effects interact with other epigenetic influences, especially early on in life? Are imprinted effects on adult behaviors adaptive or just epiphenomena? If they are adaptive, what areas of brain function and behavior might be sensitive to imprinted effects? These are big questions and, as shall become apparent, we need much more data, arising from interactions between behavioral neuroscientists, molecular biologists and evolutionary theorists, if we are to begin to answer them.     

Conservation Priorities when Species Interact: The Noah's Ark Metaphor Revisited

This note incorporates ecological interactions into the Noah''s Ark problem. In doing so, we arrive at a general model for ranking in situ conservation projects accounting for species interrelations and provide an operational cost-effectiveness method for the selection of best preserving diversity projects under a limited budget constraint.