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121.
Networks of marine reserves are increasingly being promoted as a means of conserving marine biodiversity. One consideration in designing systems of marine reserves is the maintenance of connectivity to ensure the long-term persistence and resilience of populations. Knowledge of connectivity, however, is frequently lacking during marine reserve design and establishment. We characterise patterns of genetic connectivity of 3 key species of habitat-forming macroalgae across an established network of temperate marine reserves on the east coast of Australia and the implications for adaptive management and marine reserve design. Connectivity varied greatly among species. Connectivity was high for the subtidal macroalgae Ecklonia radiata and Phyllospora comosa and neither species showed any clear patterns of genetic structuring with geographic distance within or among marine parks. In contrast, connectivity was low for the intertidal, Hormosira banksii, and there was a strong pattern of isolation by distance. Coastal topography and latitude influenced small scale patterns of genetic structure. These results suggest that some species are well served by the current system of marine reserves in place along this temperate coast but it may be warranted to revisit protection of intertidal habitats to ensure the long-term persistence of important habitat-forming macroalgae. Adaptively managing marine reserve design to maintain connectivity may ensure the long-term persistence and resilience of marine habitats and the biodiversity they support. 相似文献
122.
Inka Keränen Aapo Kahilainen K. Emily Knott Janne S. Kotiaho Katja Kuitunen 《Biological journal of the Linnean Society. Linnean Society of London》2013,108(3):534-545
Hybridization is a well‐known phenomenon, but there are still relatively few studies addressing the question of reproductive isolation between related sympatric animal species with largely overlapping ranges. Population density, relative abundance, and operational sex ratio (OSR) are among the factors known to have an influence on the frequency of heterospecific matings in sympatric populations. Here we had two aims. First, we used microsatellite markers and field observations to study the frequency of hybrids, and backcrosses, and the rate of heterospecific matings between two sympatric damselfly species Calopteryx splendens (Harris, 1780) and Calopteryx virgo (Linné, 1758). Second, we investigated the role of population densities, relative abundances, and OSRs on conspecific and heterospecific mating rates. Altogether we genotyped 2104 individuals from both species and found four hybrids (0.19%), one of which was a backcross. Of all the 272 matings observed, 17 (6%) were between heterospecifics, and all of these were between a C. splendens male and a C. virgo female. In addition, all of the hybrids contained mitochondrial DNA (mtDNA) of C. virgo. We show that the population density of C. virgo, which was the maternal species of all the heterospecific matings and hybrid individuals, was the only significant factor covarying with the rate of the heterospecific matings. The OSRs did not correlate with the rate of con‐ or heterospecific matings. Studies on interspecific interactions in sympatric species can give information about the maintenance of reproductive isolation, and thus speciation. © 2012 The Linnean Society of London 相似文献
123.
Bohumil Maco Anthony Holtmaat Marco Cantoni Anna Kreshuk Christoph N. Straehle Fred A. Hamprecht Graham W. Knott 《PloS one》2013,8(2)
Correlating in vivo imaging of neurons and their synaptic connections with electron microscopy combines dynamic and ultrastructural information. Here we describe a semi-automated technique whereby volumes of brain tissue containing axons and dendrites, previously studied in vivo, are subsequently imaged in three dimensions with focused ion beam scanning electron microcopy. These neurites are then identified and reconstructed automatically from the image series using the latest segmentation algorithms. The fast and reliable imaging and reconstruction technique avoids any specific labeling to identify the features of interest in the electron microscope, and optimises their preservation and staining for 3D analysis. 相似文献
124.
The harmony and function of the complex brain circuits and synapses are sustained mainly by excitatory and inhibitory neurotransmission,
neurotrophins, gene regulation, and factors, many of which are incompletely understood. A common feature of brain circuit
components, such as dendrites, synaptic membranes, and other membranes of the nervous system, is that they are richly endowed
in docosahexaenoic acid (DHA), the main member of the omega-3 essential fatty acid family. DHA is avidly retained and concentrated
in the nervous system and known to play a role in neuroprotection, memory, and vision. Only recently has it become apparent
why the surprisingly rapid increases in free (unesterified) DHA pool size take place at the onset of seizures or brain injury.
This phenomenon began to be clarified by the discovery of neuroprotectin D1 (NPD1), the first-uncovered bioactive docosanoid
formed from free DHA through 15-lipoxygenase-1 (15-LOX-1). NPD1 synthesis includes, as agonists, oxidative stress and neurotrophins.
The evolving concept is that DHA-derived docosanoids set in motion endogenous signaling to sustain homeostatic synaptic and
circuit integrity. NPD1 is anti-inflammatory, displays inflammatory resolving activities, and induces cell survival, which
is in contrast to the pro-inflammatory actions of the many of omega-6 fatty acid family members. We highlight here studies
relevant to the ability of DHA to sustain neuronal function and protect synapses and circuits in the context of DHA signalolipidomics.
DHA signalolipidomics comprises the integration of the cellular/tissue mechanism of DHA uptake, its distribution among cellular
compartments, the organization and function of membrane domains containing DHA phospholipids, and the precise cellular and
molecular events revealed by the uncovering of signaling pathways regulated by docosanoids endowed with prohomeostatic and
cell survival bioactivity. Therefore, this approach offers emerging targets for prevention, pharmaceutical intervention, and
clinical translation involving DHA-mediated signaling. 相似文献
125.
Omran Z Kay G Di Salvo A Knott RM Cairns D 《Bioorganic & medicinal chemistry letters》2011,21(1):45-47
The genetic disease, nephropathic cystinosis is characterized by lysosomal accumulation of the amino acid cystine. Crystallization of cystine in affected organs, if untreated, results in mortality of the affected individuals by their middle to late teens. The only approved treatment for cystinosis is administration of cysteamine. However, cysteamine is associated with an offending odor and taste and this, coupled to a rapid first pass metabolism and a 6 h dosing regimen, suggest a clear need to improve the therapy. A number of PEGylated derivatives of cystamine, the disulfide counterpart of cysteamine, have been synthesised and evaluated in cultured cystinotic fibroblasts for toxicity and efficacy. All of the tested compounds were non-cytotoxic and displayed a remarkable depletion of intralysosomal cystine. 相似文献
126.
Colin W. Hiebert Tom G. Fetch Taye Zegeye Julian B. Thomas Daryl J. Somers D. Gavin Humphreys Brent D. McCallum Sylvie Cloutier Davinder Singh Doug R. Knott 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,122(1):143-149
Stem rust (caused by Puccinia graminis Pers.:Pers. f. sp. tritici Eriks. & E. Henn.) has re-emerged as a threat to wheat production with the evolution of new pathogen races, namely TTKSK
(Ug99) and its variants, in Africa. Deployment of resistant wheat cultivars has provided long-term control of stem rust. Identification
of new resistance genes will contribute to future cultivars with broad resistance to stem rust. The related Canadian cultivars
Peace and AC Cadillac show resistance to Ug99 at the seedling stage and in the field. The purpose of this study was to elucidate
the inheritance and genetically map resistance to Ug99 in these two cultivars. Two populations were produced, an F2:3 population from LMPG/AC Cadillac and a doubled haploid (DH) population from RL6071/Peace. Both populations showed segregation
at the seedling stage for a single stem rust resistance (Sr) gene, temporarily named SrCad. SrCad was mapped to chromosome 6DS in both populations with microsatellite markers and a marker (FSD_RSA) that is tightly linked
to the common bunt resistance gene Bt10. FSD_RSA was the closest marker to SrCad (≈1.6 cM). Evaluation of the RL6071/Peace DH population and a second DH population, AC Karma/87E03-S2B1, in Kenya showed
that the combination of SrCad and leaf rust resistance gene Lr34 provided a high level of resistance to Ug99-type races in the field, whereas in the absence of Lr34 SrCad conferred moderate resistance. A survey confirmed that SrCad is the basis for all of the seedling resistance to Ug99 in Canadian wheat cultivars. While further study is needed to determine
the relationship between SrCad and other Sr genes on chromosome 6DS, SrCad represents a valuable genetic resource for producing stem rust resistant wheat cultivars. 相似文献
127.
Antunes EM Afolayan AF Chiwakata MT Fakee J Knott MG Whibley CE Hendricks DT Bolton JJ Beukes DR 《Phytochemistry》2011,72(8):769-772
Five known (1, 2, 4, 6 and 7) halogenated monoterpenes together with 1Z,3R∗,4S∗,5E,7Z)-1-bromo-3,4,8-trichloro-7-(dichloromethyl)-3-methylocta-1,5,7-triene (3) and (3R∗,4S∗)-3,4,6,7-tetrachloro-3,7-dimethyl-octen-1-ene (5) were isolated from the red macroalga Plocamium suhrii and their structures deduced from their spectroscopic data. The seven compounds from P. suhrii together with five related compounds from Plocamium cornutum have been evaluated for their cytotoxic effects on an esophageal cancer cell line (WHCO1). Compounds 1-6 showed greater cytotoxicity in this assay as compared to the known anticancer drug cisplatin. 相似文献
128.
Omran Z Moloney KA Benylles A Kay G Knott RM Cairns D 《Bioorganic & medicinal chemistry》2011,19(11):3492-3496
As part of our continuing work to obtain new pro-drugs for the treatment of nephropathic cystinosis, a number of glutaric and succinic acid derivatives of cystamine have been designed, synthesised and biologically evaluated in vitro. These compounds have been designed as odourless and tasteless pro-drugs which will release multiple molecules of cysteamine upon administration. All of the synthesised compounds evaluated in this study were non-cytotoxic and displayed a greater ability than cysteamine to deplete the levels of cystine in cultured fibroblasts. 相似文献
129.
A survey of 11 sites covering three large (>10 km long, 6 sites) playa lakes and four pans (<1 km2, 5 sites) of the Yarra Yarra salt lake system in the Northern Agricultural Region of Western Australia commenced in 2001.
These salt lakes are shallow and ephemeral, with inundation being more regular following winter rainfall, but summer inundation
also occurred in 2001. Salinity was generally higher in playas (156–368 g l−1) than pans (30–284 g l−1), but salinity responded noticeably to heavy rainfall events, especially in pans. pH values in the playa lakes (6.68–7.82)
were less variable than in the pans (6.81–8.08). The range of dissolved oxygen concentrations was greater in pans (3.7–14.4
mg l−1) than in playas (3.9–8.2 mg l−1). Cationic concentrations generally followed the pattern of sea water cation dominance. Benthic microbial communities comprised
either cohesive to loosely mucilaginous mats, or thin films of diatoms. Five genera of diatom and two species of filamentous
cyanobacteria were recorded.
Guest Editor: John M. Melack
Saline Waters and their Biota 相似文献
130.
Jessica Lynas Andrew W. Storey Brenton Knott 《Marine and Freshwater Behaviour and Physiology》2007,40(2):105-116
The freshwater crayfish, Cherax destructor Clark, native to southeastern Australia, was first introduced to farm dams in southwestern Western Australia in 1932. The geographic range of the crayfish in Western Australia has increased substantially since then, and in recent years it has become established in natural waterways where it co-occurs with species of freshwater crayfish endemic to southwestern Australia, Cherax cainii and Cherax quinquecarinatus. The potential for competitive exclusion of these endemic species by C. destructor was investigated through laboratory experiments measuring aggressive behaviour. Body mass and species were found to be important factors governing aggressive dominance between C. cainii and C. destructor, with C. cainii winning significantly more interactions only when they were larger in body mass than their opponent. In trials between C. quinquecarinatus and C. destructor of similar body mass, there was no difference between the number of interactions 'won' by the two species. The implications for natural populations are discussed. 相似文献