The global potential for Agave as a biofuel feedstock

Large areas of the tropics and subtropics are too arid or degraded to support food crops, but Agave species may be suitable for biofuel production in these regions. We review the potential of Agave species as biofuel feedstocks in the context of ecophysiology, agronomy, and land availability for this genus globally. Reported dry biomass yields of Agave spp., when annualized, range from <1 to 34 Mg ha^?1 yr^?1 without irrigation, depending on species and location. Some of the most productive species have not yet been evaluated at a commercial scale. Approximately 0.6 Mha of land previously used to grow Agave for coarse fibers have fallen out of production, largely as a result of competition with synthetic fibers. Theoretically, this crop area alone could provide 6.1 billion L of ethanol if Agave were re‐established as a bioenergy feedstock without causing indirect land use change. Almost one‐fifth of the global land surface is semiarid, suggesting there may be large opportunities for expansion of Agave crops for feedstock, but more field trials are needed to determine tolerance boundaries for different Agave species.     

多因素异常修饰导致体内蛋白质选择性错误折叠和功能丧失的假设

蛋白质异常修饰导致错误折叠的机制目前尚不清楚.提出如下设想:细胞内的蛋白质分子可能发生多种异常修饰,引起蛋白质选择性错误折叠和聚积而导致神经退行性疾病.     

Species: towards new, well-grounded practices

Velasco recently criticized our formal definition of the species concept, arguing for its inappropriateness both in fundamental and practical aspects [Velasco JD (2008) Biological Journal of the Linnean Society , 93 , 865–869]. Here, we clarify some misunderstandings that are at the basis of Velasco's paper. First, we show why and how the definition of the species concept can be grounded in the theory of evolution and what that implies. Then, we explain why Velasco's formal criticisms are unjustified. Finally, we point out the practical and methodological consequences of a rigorous conceptual framework for species study, and we show that today's development of species delimitation methods fully agrees with our proposal.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 97 , 217–222.     

Isolation of microsatellite markers for the endangered Knysna seahorse Hippocampus capensis and their use in the detection of a genetic bottleneck

We report the isolation and characterization of 15 (12 di‐, 1 tri‐ and 2 tetranucleotide) microsatellite markers from Hippocampus capensis, the Knysna seahorse. This marker set allows the detection of a genetic bottleneck as shown in a captive population. Furthermore, we test their genotyping potential in eight other seahorse taxa.     

Density and variability of dinucleotide microsatellites in the parthenogenetic polyploid snail Melanoides tuberculata

Characterization of microsatellites in the parthenogenetic polyploid snail Melanoides tuberculata revealed an unusual high density of dinucleotide repeats. Multiple banding patterns were obtained at these loci, and interpreted as a consequence of polyploidy. Microsatellite variability was low within, but high between, shell morphotypes. Genotypes were wholly transmitted from mothers to offspring. These results suggest that reproduction is strictly apomictic, and that shell morphotypes are genetic clones.     

Temporal changes of gene frequencies in Cepaea hortensis

There have been few studies analysing long-term changes of gene frequencies in natural populations. This work is the first report of such changes in the land snail Cepaea hortensis (Mull).
Collections of C. hortensis were made at Silbury Hill, Wiltshire in 1957, 1963 and 1978. The banded phenotype significantly declined in frequency between 1963 and 1978. It is argued that the decline, which was statistically homogeneous at 15 separate sites within the area, was a consequence of natural selection. The average selection coefficient against the banded homozygote is estimated to have been greater than 1096.     

Geographical variation in male advertisement calls and female preference of the wide‐ranging canyon treefrog,Hyla arenicolor

We surveyed the geographical variation in male advertisement calls of the wide‐ranging canyon treefrog, Hyla arenicolor, and found large call differences among geographically distant lineages that had been characterized by a recent phylogeographical study. To test whether these call differences were biologically relevant and could allow reproductive isolation of different lineages should they come into secondary contact, we assessed female preference in a lineage occurring in southern Utah and north‐western Arizona, USA. These females exhibited a strong preference for their own lineage's call type over the calls of two Mexican lineages, but not over the calls from the geographically nearest lineage. We also identified traits that female frogs probably use to discriminate between lineage‐specific advertisement calls. Our behavioural results, together with recent molecular estimates of phylogenetic relationships among lineages, will guide future work addressing the evolutionary forces that have led to this biologically significant variation in male sexual signals. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ??, ??–??.     

Improving biodiversity monitoring

Effective biodiversity monitoring is critical to evaluate, learn from, and ultimately improve conservation practice. Well conceived, designed and implemented monitoring of biodiversity should: (i) deliver information on trends in key aspects of biodiversity (e.g. population changes); (ii) provide early warning of problems that might otherwise be difficult or expensive to reverse; (iii) generate quantifiable evidence of conservation successes (e.g. species recovery following management) and conservation failures; (iv) highlight ways to make management more effective; and (v) provide information on return on conservation investment. The importance of effective biodiversity monitoring is widely recognized (e.g. Australian Biodiversity Strategy). Yet, while everyone thinks biodiversity monitoring is a good idea, this has not translated into a culture of sound biodiversity monitoring, or widespread use of monitoring data. We identify four barriers to more effective biodiversity monitoring in Australia. These are: (i) many conservation programmes have poorly articulated or vague objectives against which it is difficult to measure progress contributing to design and implementation problems; (ii) the case for long‐term and sustained biodiversity monitoring is often poorly developed and/or articulated; (iii) there is often a lack of appropriate institutional support, co‐ordination, and targeted funding for biodiversity monitoring; and (iv) there is often a lack of appropriate standards to guide monitoring activities and make data available from these programmes. To deal with these issues, we suggest that policy makers, resource managers and scientists better and more explicitly articulate the objectives of biodiversity monitoring and better demonstrate the case for greater investments in biodiversitymonitoring. There is an urgent need for improved institutional support for biodiversity monitoring in Australia, for improved monitoring standards, and for improved archiving of, and access to, monitoring data. We suggest that more strategic financial, institutional and intellectual investments in monitoring will lead to more efficient use of the resources available for biodiversity conservation and ultimately better conservation outcomes.