23 research outputs found
Evolutionary rates for multivariate traits: the role of selection and genetic variation.
No full textThis is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.A fundamental question in evolutionary biology is the relative importance of selection and genetic architecture in determining evolutionary rates. Adaptive evolution can be described by the multivariate breeders' equation (Δz(-)=Gβ), which predicts evolutionary change for a suite of phenotypic traits (Δz(-)) as a product of directional selection acting on them (β) and the genetic variance-covariance matrix for those traits (G ). Despite being empirically challenging to estimate, there are enough published estimates of G and β to allow for synthesis of general patterns across species. We use published estimates to test the hypotheses that there are systematic differences in the rate of evolution among trait types, and that these differences are, in part, due to genetic architecture. We find some evidence that sexually selected traits exhibit faster rates of evolution compared with life-history or morphological traits. This difference does not appear to be related to stronger selection on sexually selected traits. Using numerous proposed approaches to quantifying the shape, size and structure of G, we examine how these parameters relate to one another, and how they vary among taxonomic and trait groupings. Despite considerable variation, they do not explain the observed differences in evolutionary rates.J.H., T.T. and J.B.W. were supported by NERC, J.H. and J.B.W. by the BBSRC and J.H. by a University Royal Society Fellowship. W.P. was supported by an NERC studentship (awarded to J.H. and T.T.) and I.D. and W.P. were funded by NIH grant no. 1R01GM094424
From Chip-in-a-lab To Lab-on-a-chip: Towards A Single Handheld Electronic System For Multiple Application-specific Lab-on-a-chip (asloc)
No full textWe present a portable, battery-operated and application-specific lab-on-a-chip (ASLOC) system that can be easily configured for a wide range of lab-on-a-chip applications. It is based on multiplexed electrical current detection that serves as the sensing system. We demonstrate different configurations to perform most detection schemes currently in use in LOC systems, including some of the most advanced such as nanowire-based biosensing, surface plasmon resonance sensing, electrochemical detection and real-time PCR. The complete system is controlled by a single chip and the collected information is stored in situ, with the option of transferring the data to an external display by using a USB interface. In addition to providing a framework for truly portable real-life developments of LOC systems, we envisage that this system will have a significant impact on education, especially since it can easily demonstrate the benefits of integrated microanalytical systems. © the Partner Organisations 2014.141321682176Manz, A., Graber, N., Widmer, H.M., (1990) Sens. Actuators, B, 1, pp. 244-248Ríos, Á., Zougagh, M., Avila, M., (2012) Anal. Chim. Acta, 740, pp. 1-11Elvira, K.S., Solvas, X.C.I., Wootton, R.C.R., Demello, A.J., (2013) Nat. Chem., 5, pp. 905-915Nge, P.N., Rogers, C.I., Woolley, A.T., (2013) Chem. Rev., 113, pp. 2550-2583Kaushik, A., Vasudev, A., Arya, S.K., Pasha, S.K., Bhansali, S., (2014) Biosens. Bioelectron., 53, pp. 499-512Han, K.N., Li, C.A., Seong, G.H., (2013) Annu. Rev. Anal. Chem., 6, pp. 119-141Lee, J., Lee, S.-H., (2013) Biomed. Eng. Lett., 3, pp. 59-66Lewis, A.P., Cranny, A., Harris, N.R., Green, N.G., Wharton, J.A., Wood, R.J.K., Stokes, K.R., (2013) Meas. Sci. Technol., 24, p. 042001Yushan, Z., Jacquemod, C., Sawan, M., (2013) 2013 IEEE International Symposium on Circuits and Systems (ISCAS), , Beijing, China, 1071-1074Yang, J., Brooks, C., Estes, M.D., Hurth, C.M., Zenhausern, F., (2014) Forensic Sci. Int.: Genet., 8, pp. 147-158Czugala, M., Maher, D., Collins, F., Burger, R., Hopfgartner, F., Yang, Y., Zhaou, J., Diamond, D., (2013) RSC Adv., 3, pp. 15928-15938Legiret, F.-E., Sieben, V.J., Woodward, E.M.S., Abi Kaed Bey, S.K., Mowlem, M.C., Connelly, D.P., Achterberg, E.P., (2013) Talanta, 116, pp. 382-387Fernández-La-Villa, A., Sánchez-Barragán, D., Pozo-Ayuso, D.F., Castaño-Álvarez, M., (2012) Electrophoresis, 33, pp. 2733-2742Wang, S., Inci, F., Chaunzwa, T.L., Ramanujam, A., Vasudevan, A., Subramanian, S., Ip, A.C.F., Demirci, U., (2012) Int. J. Nanomed., 7, pp. 2591-2600Lillehoj, P.B., Huang, M.C., Ho, C.M., (2013) 2013 IEEE 26th International Conference on Micro Electro Mechanical Systems (MEMS), , Taipei, Taiwan, 53-56Ansari, K., Ying, J.Y.S., Hauser, P.C., De Rooij, N.F., Rodriguez, I., (2013) Electrophoresis, 34, pp. 1390-1399Toumazou, C., Shepherd, L.M., Reed, S.C., Chen, G.I., Patel, A., Garner, D.M., Wang, C.J., Zhang, L., (2013) Nat. Methods, 10, pp. 641-646Fintschenko, Y., (2011) Lab Chip, 11, pp. 3394-3400Hemling, M., Crooks, J.A., Oliver, P.M., Brenner, K., Gilbertson, J., Lisensky, G.C., Weibel, D.B., (2013) J. Chem. Educ., 91, pp. 112-115Yang, C.W., Lagally, E.T., (2013) Methods Mol. Biol., 949, pp. 25-40Priye, A., Hassan, Y.A., Ugaz, V.M., (2012) Lab Chip, 12, pp. 4946-4954Neuzil, P., Pipper, J., Hsieh, T.M., (2006) Mol. BioSyst., 2, pp. 292-298Neuzil, P., Zhang, C., Pipper, J., Oh, S., Zhuo, L., (2006) Nucleic Acids Res., 34, p. 77Novak, L., Neuzil, P., Pipper, J., Zhang, Y., Lee, S., (2007) Lab Chip, 7, pp. 27-29Pipper, J., Inoue, M., Ng, L.F., Neuzil, P., Zhang, Y., Novak, L., (2007) Nat. Med., 13, pp. 1259-1263Pipper, J., Zhang, Y., Neuzil, P., Hsieh, T.M., (2008) Angew. Chem., Int. Ed., 47, pp. 3900-3904Neuzil, P., Novak, L., Pipper, J., Lee, S., Ng, L.F., Zhang, C., (2010) Lab Chip, 10, pp. 2632-2634Neuzil, P., Reboud, J., (2008) Anal. Chem., 80, pp. 6100-6103Novak, L., Neuzil, P., Woon, J.S.B., Wee, Y., (2009) IEEE Sensors 2009 Conference, , Christchurch, New Zealand, 405-407Gaydos, C.A., Van Der Pol, B., Jett-Goheen, M., Barnes, M., Quinn, N., Clark, C., Daniel, G.E., Hook III, E.W., (2013) J. Clin. Microbiol., 51, pp. 1666-1672Neuzil, P., Wong, C.C., Reboud, J., (2010) Nano Lett., 10, pp. 1248-1252Cui, Y., Wei, Q., Park, H., Lieber, C.M., (2001) Science, 293, pp. 1289-1292Zhang, G.J., Luo, Z.H., Huang, M.J., Ang, J.J., Kang, T.G., Ji, H., (2011) Biosens. Bioelectron., 28, pp. 459-463Zhang, G.J., Zhang, G., Chua, J.H., Chee, R.E., Wong, E.H., Agarwal, A., Buddharaju, K.D., Balasubramanian, N., (2008) Nano Lett., 8, pp. 1066-1070Cumyn, V.K., Fleischauer, M.D., Hatchard, T.D., Dahn, J.R., (2003) Electrochem. Solid-State Lett., 6, pp. E15-E18Drake, K.F., Van Duyne, R.P., Bond, A.M., (1978) J. Electroanal. Chem., 89, pp. 231-24
From chip-in-a-lab to lab-on-a-chip: towards a single handheld electronic system for multiple application-specific lab-on-a-chip (ASLOC)
No full textWe present a portable, battery-operated and application-specific lab-on-a-chip (ASLOC) system that can be easily configured for a wide range of lab-on-a-chip applications. It is based on multiplexed electrical current detection that serves as the sensing system. We demonstrate different configurations to perform most detection schemes currently in use in LOC systems, including some of the most advanced such as nanowire-based biosensing, surface plasmon resonance sensing, electrochemical detection and real-time PCR. The complete system is controlled by a single chip and the collected information is stored in situ, with the option of transferring the data to an external display by using a USB interface. In addition to providing a framework for truly portable real-life developments of LOC systems, we envisage that this system will have a significant impact on education, especially since it can easily demonstrate the benefits of integrated microanalytical systems
Episymbiotic microbes as food and defence for marine isopods : unique symbioses in a hostile environment
No full textAuthor Posting. © Royal Society, 2005. This article is posted here by permission of
Royal Society for personal use, not for redistribution. The definitive version was published
in Proceedings of the Royal Society of London B 272 (2005): 1209-1216, doi:10.1098/rspb.2005.3082.Symbioses profoundly affect the diversity of life, often through novel biochemical services that symbionts provide to their hosts. These biochemical services are typically nutritional enhancements and less commonly defensive, but rarely both simultaneously. On the coral reefs of Papua New Guinea, we discovered unique associations between marine isopod crustaceans (Santia spp.) and episymbiotic microbes. Transmission electron microscopy and pigment analyses show that episymbiont biomass is dominated by large (20–30μm) cyanobacterial cells. The isopods consume these photosymbionts and ‘cultivate’ them by inhabiting exposed sunlit substrates, a behaviour made possible by symbionts' production of a chemical defence that is repulsive to fishes. Molecular phylogenetic analyses demonstrated that the symbiotic microbial communities are diverse and probably dominated in terms of population size by bacteria and small unicellular Synechococcus-type cyanobacteria. Although largely unknown in the oceans, defensive symbioses probably promote marine biodiversity by allowing niche expansions into otherwise hostile environments.This work was supported by an NSF Predoctoral Fellowship
awarded to J.B.W and a grant from the North Carolina
Biotechnology Center to N.L and Richard Manderville
(Wake Forest University)
Zooplankton abundance reflects oxygen concentration and dissolved organic matter in a seasonally hypoxic estuary
No full text© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Weinstock, J., Vargas, L., & Collin, R. Zooplankton abundance reflects oxygen concentration and dissolved organic matter in a seasonally hypoxic estuary. Journal of Marine Science and Engineering, 10(3), (2022): 427, https://doi.org/10.3390/jmse10030427.Ocean deoxygenation, warming, and acidification resulting from global change and increasing nutrient inputs are major threats to marine ecosystems. Despite this, spatial and temporal patterns of oxygen availability and their impacts on marine life are understudied compared to warming and acidification, particularly in coastal tropical ecosystems. We measured the abundance of major groups of zooplankton in the context of five covarying environmental parameters [temperature, salinity, dissolved oxygen (DO), dissolved organic matter (DOM), and chlorophyll concentration] in a tropical estuary for one year. Partial least squares demonstrated that environmental conditions explained 20% of the variation in the community and found that temperature, salinity, DO, and DOM were most important (Variable Importance in Projection [VIP] > 0.8). A generalized linear model identified depth, DO, salinity, and chlorophyll as significant main effects, and temperature and DOM were also significant via two-way interactions (p < 0.05). When examined separately, the abundance of each zooplankton group was explained by a slightly different combination of environmental factors, but in all cases DO had large, significant effects, and in most cases DOM or its interactions were also significant. These results demonstrate that the seasonal cycle of hypoxia in this system significantly impacts the abundance of major zooplankton groups and likely also recruitment of benthic fauna through impacts on meroplankton and benthic-pelagic food webs.This research was funded by a Fulbright Fellowship awarded to J.B.W. and a Smithsonian Tropical Research Institute internship awarded to L.V
The utility of volunteer home-visiting support to prevent maternal depression in the first year of life
No full textBackground Maternal depression can be detrimental to infant development. Structured home visiting initiated either in pregnancy or soon after the birth by a professional has led to better outcomes for mothers and their children but some vulnerable families may respond more favourably to a local volunteer. The value of volunteer support provided in the UK by Home-Start for maternal well-being is noted in qualitative studies, but there is no evidence of its impact from trials. The support is not structured and both the frequency and content of visits may vary.
Methods A cluster randomized study allocated Home-Start local schemes to intervention or control conditions. Mothers in all areas were screened at routine health checks in late pregnancy. In intervention areas names of those scoring 9+ on the Social Disadvantage Screening Index were passed to Home-Start to be offered a volunteer. Not all those offered the support accepted the offer. In control areas no support was offered. Research assessments were conducted at 2 and 12 months. The outcomes were major or minor depression occurring between 2 and 12 months (Structured Clinical Interview for Diagnostic and Statistical Manual – Third Edition – Revised) and depression symptoms at 12 months (Edinburgh Postnatal Depression Scale). Three groups were compared: supported, case-matched controls and those offered but not receiving support.
Results Almost one-third experienced depression during the time period. Volunteer support had no identifiable impact on the emergence of maternal depression from 2 to 12 months or on depression symptoms when infants were 12 months. The major predictor of both was depression identified at 2 months.
Conclusions It was not found that informal support initiated following screening for disadvantage in pregnancy reduced the likelihood of depression for mothers with infants
Demonstrating the self-healing behaviour of some selected ceramics under combustion chamber conditions
No full textClosure of surface cracks by self-healing of conventional and MAX phase ceramics under realistic turbulent combustion chamber conditions is presented. Three ceramics namely; Al2O3, Ti2AlC and Cr2AlC are investigated. Healing was achieved in Al2O3 by even dispersion of TiC particles throughout the matrix as the MAX phases, Ti2AlC and Cr2AlC exhibit intrinsic self-healing. Fully dense samples (>95%) were sintered by spark plasma sintering and damage was introduced by indentation, quenching and low perpendicular velocity impact methods. The samples were exposed to the oxidizing atmosphere in the post flame zone of a turbulent flame in a combustion chamber to heal at temperatures of approx. 1000 °C at low pO2 levels for 4 h. Full crack-gap closure was observed for cracks up to 20 mm in length and more than 10 μm in width. The reaction products (healing agents) were analysed by scanning electron microscope, x-ray microanalysis and XRD. A semi-quantification of the healing showed that cracks in Al2O3/TiC composite (width 1 μm and length 100 μm) were fully filled with TiO2. In Ti2AlC large cracks were fully filled with a mixture of TiO2 and Al2O3. And in the Cr2AlC, cracks of up to 1.0 μm in width and more than 100 μm in length were also completely filled with Al2O3
Resolution of Prochlorococcus and Synechococcus ecotypes by using 16S-23S ribosomal DNA internal transcribed spacer sequences
No full textAuthor Posting. © American Society for Microbiology, 2002. This article is posted here by permission of American Society for Microbiology for personal use, not for redistribution. The definitive version was published in Applied and Environmental Microbiology 68 (2002): 1180-1191, doi:10.1128/AEM.68.3.1180-1191.2002.Cultured isolates of the marine cyanobacteria Prochlorococcus and Synechococcus vary widely in their pigment compositions and growth responses to light and nutrients, yet show greater than 96% identity in their 16S ribosomal DNA (rDNA) sequences. In order to better define the genetic variation that accompanies their physiological diversity, sequences for the 16S-23S rDNA internal transcribed spacer (ITS) region were determined in 32 Prochlorococcus isolates and 25 Synechococcus isolates from around the globe. Each strain examined yielded one ITS sequence that contained two tRNA genes. Dramatic variations in the length and G+C content of the spacer were observed among the strains, particularly among Prochlorococcus strains. Secondary-structure models of the ITS were predicted in order to facilitate alignment of the sequences for phylogenetic analyses. The previously observed division of Prochlorococcus into two ecotypes (called high and low-B/A after their differences in chlorophyll content) were supported, as was the subdivision of the high-B/A ecotype into four genetically distinct clades. ITS-based phylogenies partitioned marine cluster A Synechococcus into six clades, three of which can be associated with a particular phenotype (motility, chromatic adaptation, and lack of phycourobilin). The pattern of sequence divergence within and between clades is suggestive of a mode of evolution driven by adaptive sweeps and implies that each clade represents an ecologically distinct population. Furthermore, many of the clades consist of strains isolated from disparate regions of the world's oceans, implying that they are geographically widely distributed. These results provide further evidence that natural populations of Prochlorococcus and Synechococcus consist of multiple coexisting ecotypes, genetically closely related but physiologically distinct, which may vary in relative abundance with changing environmental conditions.This work was supported by an NSF graduate fellowship to G.R., by
NASA grant NAG5-3727 and NSF grant OCE9820035 to S.W.C., and
by NSF grant OCE9315895 to D.L.D. and J.B.W
