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Endophytic fungi, especially asexual, systemic endophytes in grasses, are generally viewed as plant mutualists, mainly through the action of mycotoxins, such as alkaloids in infected grasses, which protect the host plant from herbivores. Most of the evidence for the defensive mutualism concept is derived from studies of agronomic grass cultivars, which may be atypical of many endophyte-host interactions. I argue that endophytes in native plants, even asexual, seed-borne ones, rarely act as defensive mutualists. In contrast to domesticated grasses where infection frequencies of highly toxic plants often approach 100%, natural grass populations are usually mosaics of uninfected and infected plants. The latter, however, usually vary enormously in alkaloid levels, from none to levels that may affect herbivores. This variation may result from diverse endophyte and host genotypic combinations that are maintained by changing selective pressures, such as competition, herbivory and abiotic factors. Other processes, such as spatial structuring of host populations and endophytes that act as reproductive parasites of their hosts, may maintain infection levels of seed-borne endophytes in natural populations, without the endophyte acting as a mutualist.

Myostatin (GDF-8) is a member of the transforming growth factor β superfamily of secreted growth and differentiation factors that is essential for proper regulation of skeletal muscle mass in mice. Here we report the myostatin sequences of nine other vertebrate species and the identification of mutations in the coding sequence of bovine myostatin in two breeds of double-muscled cattle, Belgian Blue and Piedmontese, which are known to have an increase in muscle mass relative to conventional cattle. The Belgian Blue myostatin sequence contains an 11-nucleotide deletion in the third exon which causes a frameshift that eliminates virtually all of the mature, active region of the molecule. The Piedmontese myostatin sequence contains a missense mutation in exon 3, resulting in a substitution of tyrosine for an invariant cysteine in the mature region of the protein. The similarity in phenotypes of double-muscled cattle and myostatin null mice suggests that myostatin performs the same biological function in these two species and is a potentially useful target for genetic manipulation in other farm animals.

The fiftieth anniversary edition of a landmark publication showcasing prehistoric North American landscapes and ecosystems, from a celebrated paleontologist at Yale University's Peabody Museum The fiftieth anniversary edition of John H. Ostrom's Stratigraphy and Paleontology of the Cloverly Formation revisits his groundbreaking work pinpointing the age of the continental sequence of the Bighorn Basin area in Wyoming and Montana. The Cloverly Formation is important for understanding the development of North American terrestrial landscapes and prehistoric ecosystems, and current investigations are reinterpreting the age of the Formation with new evidence and data. The reissue of Ostrom's original benchmark research offers contemporary relevance for researchers and students today.

To connect human biology to fish biomedical models, we sequenced the genome of spotted gar (Lepisosteus oculatus), whose lineage diverged from teleosts before teleost genome duplication (TGD). The slowly evolving gar genome has conserved in content and size many entire chromosomes from bony vertebrate ancestors. Gar bridges teleosts to tetrapods by illuminating the evolution of immunity, mineralization and development (mediated, for example, by Hox, ParaHox and microRNA genes). Numerous conserved noncoding elements (CNEs; often cis regulatory) undetectable in direct human-teleost comparisons become apparent using gar: functional studies uncovered conserved roles for such cryptic CNEs, facilitating annotation of sequences identified in human genome-wide association studies. Transcriptomic analyses showed that the sums of expression domains and expression levels for duplicated teleost genes often approximate the patterns and levels of expression for gar genes, consistent with subfunctionalization. The gar genome provides a resource for understanding evolution after genome duplication, the origin of vertebrate genomes and the function of human regulatory sequences.

The effects of grazing by white-tailed deer (Odocoileus virginianus) on populations of Trillium spp. were examined in remnant, old-growth patches of the highly fragmented Big Woods forest ecosystem in southeastern Minnesota. We conducted three separate studies involving an exclosure experiment, transplant experiments, and comparisons of Trillium populations among study sites. The highest grazing intensity was observed where deer occurred at high overwinter concentrations (∼ 25-35/km2); significantly lower grazing intensities occurred at low overwinter density (∼ 5-10/km2). Deer focused their grazing on large, reproductive plants; at sites with high deer density, Trillium population structure was skewed toward small plants, and deer consistently caused over 50% reduction in reproduction during the growing season. Protection of individual plants from deer for two growing seasons resulted in dramatically increased flowering rates and significantly greater leaf area compared to control plants. No significant impact of current-year herbivory on reproduction in the following year was detected. Nevertheless, flowering rates at one site with high overwinter deer densities for at least the past 5 years suggest that the cumulative effects of grazing over several years can reduce reproduction in subsequent years. Transplant experiments with Trillium grandiflorum also showed that deer had significant effects on growth and reproduction where deer occur at high density. Our results suggest that changes in landscape structure and local deer abundance have altered plant-deer relationships such that grazing can lead to the local extirpation of sensitive forbs such as Trillium spp. As a result, active, long-term management of deer at low densities appears necessary for the conservation and restoration of fragmented forest communities in eastern North America.

Evolutionary novelties require rewiring of transcriptional networks and/or the evolution of new gene functions. Sex determination (SD), one of the most plastic evolutionary processes, requires such novelties. Studies on the evolution of vertebrate SD revealed that new master SD genes are generally recruited from genes involved in the downstream SD regulatory genetic network. Only a single exception to this rule is currently known in vertebrates: the intriguing case of the salmonid master SD gene (sdY), which arose from duplication of an immune-related gene. This exception immediately posed the question of how a gene outside from the classical sex differentiation cascade could acquire its function as a male SD gene. Here we show that SdY became integrated in the classical vertebrate sex differentiation cascade by interacting with the Forkhead box domain of the female-determining transcription factor, Foxl2. In the presence of Foxl2, SdY is translocated to the nucleus where the SdY:Foxl2 complex prevents activation of the aromatase (cyp19a1a) promoter in cooperation with Nr5a1 (Sf1). Hence, by blocking a positive loop of regulation needed for the synthesis of estrogens in the early differentiating gonad, SdY disrupts a preset female differentiation pathway, consequently allowing testicular differentiation to proceed. These results also suggest that the evolution of unusual vertebrate master sex determination genes recruited from outside the classical pathway like sdY is strongly constrained by their ability to interact with the canonical gonadal differentiation pathway.

Interspecies chemical communication is widespread among many groups of organisms, including vertebrates. Kairomones belong to a group of intensively researched substances, represent means for interspecific chemical communication in animals and bring benefit to the acceptor of the chemical signal. Important and often studied is the chemical communication between hosts and their ectoparasites such as ticks and other parasitic mite species. Uric acid is a host stimulus of the kairomone type, which is a product of bird metabolism, or secretions of blood-fed (ingested) ticks. Secretion of volatile substances with kairomone effect may depend on the health of the host organism. Another examined group is the haematophagous ectoparasite insects of the order Diptera, where in addition to the attractiveness of CO2 a number of other attractants have been described. Specificity of substances in chemical communication can also be determined by their enantiomers. Detailed study of the biology of these ectoparasites is very important from a practical point of view: these parasites play an important role as vectors in a number of infectious diseases. Another area of interspecific chemical communication is the predator-prey relationship, or rather the ability to detect the proximity of predator and induce anti-predator behaviour in the prey. This relationship has been demonstrated in aquatic vertebrates (otter Lutra lutra - salmon Salmo salar) as well as in rodents and their predators. The substances produced by carnivores that induce behavioural response in mice have already been identified. The knowledge of interspecies communication (e.g., between host and parasite) is becoming a prerequisite in successful animal breeding and care.

The presented video explains the technique of posterior fixation of the atlantoaxial joints in patients with atlantoaxial instability. Prof. Atul Goel has pioneered the method and is the gold standard used to fix the craniovertebral junction. The technique consists of opening the C1 C2 joint, denuding the joint's articular cartilage, putting bone chips into the joint, and performing a plate and screw fixation of the region. The C1 screw is through the lateral mass of C1, and the C2 screw engages the C2 pedicle. It demonstrates the nuances to perform a solid atlantoaxial fixation. The targeted audience includes neurosurgeons and spine surgeons. The viewer will learn the tricks for performing an ideal C1-C2 fixation.

Data collected by the Gap Analysis Program in the state of Idaho (U.S.A.) are used to prioritize the selection of locations for conservation action and research. Set coverage and integer programming algorithms provide a sequence of localities that maximize the number of species or vegetation classes represented at each step. Richness maps of vegetation cover class diversity, terrestrial vertebrate species diversity (\"hot spot analysis\"), when prioritized, show a rapid accumulation of species as more localities are chosen for terrestrial vertebrates and unprotected vertebrates. Gap analysis identifies four target areas (\"gaps\") that include 79 of the 83 vertebrate species not currently protected. Accumulation of vegetation cover classes and endangered, threatened, and candidate species is much slower. Sweep analysis is used to determine how well prioritizing on one component of diversity accumulates other components. Endangered, threatened, and candidate species do not sweep endangered, threatened, and candidate species better than vegetation classes. Total vertebrates sweep endangered, threatened, and candidate species better than unprotected vertebrates do, which in turn are better than vegetation classes. We emphasize that prioritization must be part of conservation efforts at multiple scales and that prioritization points out important localities where more detailed work must be undertaken.

Urbanization is modifying previously pristine natural habitats and creating “new” ecosystems for wildlife. As a result, some animals now use habitat fragments or have colonized urban areas. Such animals are exposed to novel stimuli that they have not been exposed to in their evolutionary history. Some species have adapted to the challenges they face – a phenomenon known as synurbanization – while others have not. Here we present a review of the sublethal consequences of life in the city for wild vertebrates, and demonstrate that urban animals face an almost completely different set of physiological and behavioural challenges compared to their rural counterparts. We focus on the negative fitness-related impacts of urbanization, but also identify instances where there are benefits to wildlife. The effects of urbanization appear to be both species- and context-dependent, suggesting that although the field of urban ecology is far from nascent, we are still just beginning to understand how the intricacies of biodiversity on our planet are affected by our presence.