Within-family marker-assisted selection for aquaculture species

A within-family marker-assisted selection scheme was designed for typical aquaculture breeding schemes, where most traits are recorded on sibs of the candidates. Here, sibs of candidates were tested for the trait and genotyped to establish genetic marker effects on the trait. BLUP breeding values were calculated, including information of the markers (MAS) or not (NONMAS). These breeding values were identical for all family members in the NONMAS schemes, but differed between family members in the MAS schemes, making within-family selection possible. MAS had up to twice the total genetic gain of the corresponding NONMAS scheme. MAS was somewhat less effective when heritability increased from 0.06 to 0.12 or when the frequency of the positive allele was < 0.5. The relative efficiency of MAS was higher for schemes with more candidates, because of larger fullsib family sizes. MAS was also more efficient when male:female mating ratio changed from 1:1 to 1:5 or when the QTL explained more of the total genetic variation. Four instead of two markers linked to the QTL increased genetic gain somewhat. There was no significant difference in polygenic genetic gain between MAS and NONMAS for most schemes. The rates of inbreeding were lower for MAS than NON-MAS schemes, because fewer full-sibs were selected by MAS.     

Polymers for enhanced oil recovery: fundamentals and selection criteria

With a rising population, the demand for energy has increased over the years. As per the projections, both fossil fuel and renewables will remain as major energy source (678 quadrillion BTU) till 2030 with fossil fuel contributing 78% of total energy consumption. Hence, attempts are continuously made to make fossil fuel production more sustainable and cheaper. From the past 40 years, polymer flooding has been carried out in marginal oil fields and have proved to be successful in many cases. The common expectation from polymer flooding is to obtain 50% ultimate recovery with 15 to 20% incremental recovery over secondary water flooding. Both naturally derived polymers like xanthan gum and synthetic polymers like partially hydrolyzed polyacrylamide (HPAM) have been used for this purpose. Earlier laboratory and field trials revealed that salinity and temperature are the major issues with the synthetic polymers that lead to polymer degradation and adsorption on the rock surface. Microbial degradation and concentration are major issues with naturally derived polymers leading to loss of viscosity and pore throat plugging. Earlier studies also revealed that polymer flooding is successful in the fields where oil viscosity is quite higher (up to 126 cp) than injection water due to improvement in mobility ratio during polymer flooding. The largest successful polymer flood was reported in China in 1990 where both synthetic and naturally derived polymers were used in nearly 20 projects. The implementation of these projects provides valuable suggestions for further improving the available processes in future. This paper examines the selection criteria of polymer, field characteristics that support polymer floods and recommendation to design a large producing polymer flooding.     

An introduction to mass cytometry: fundamentals and applications

Mass cytometry addresses the analytical challenges of polychromatic flow cytometry by using metal atoms as tags rather than fluorophores and atomic mass spectrometry as the detector rather than photon optics. The many available enriched stable isotopes of the transition elements can provide up to 100 distinguishable reporting tags, which can be measured simultaneously because of the essential independence of detection provided by the mass spectrometer. We discuss the adaptation of traditional inductively coupled plasma mass spectrometry to cytometry applications. We focus on the generation of cytometry-compatible data and on approaches to unsupervised multivariate clustering analysis. Finally, we provide a high-level review of some recent benchmark reports that highlight the potential for massively multi-parameter mass cytometry.     

Ecological studies on ectomycorrhizal fungi: an introduction

Abstract

The characteristics of mycorrhizal associations in general and of different kinds of mycorrhizas are briefly indicated. The morphology, functional relationships, distribution, host specifity, succession and decline of ectomycorrhizas are concisely treated. Methods, advantages and limitations of four main approaches to ectomycorrhizal research are discussed. At the end an example of an attempt to an integrated approach is given.     

Strategies for regulation of aquaculture site selection in coastal areas

Marine fish farming is a relatively new component in the complex mixture of coastal resource uses in north temperate zone countries. In Western Canada, the Province of British Columbia issues site and operational licences for marine fish farms. Before granting licenses, staff evaluate fish farm applications for their technical feasibility as part of a conflict resolution process. This ensures that aquaculture develops in an environmental responsible manner, and is part of a public accountability process that recognises the interests of conflicting marine resource users. A referral system which solicits input from national and local organisations is part of this licensing process. The Norwegian YS for ordering salmon farming industry development involves partitioning the coast at a national level and developing organic loading maxima for each section of the coast. Within the constraints of this national plan Leaf authorities license aquaculture. This paper describes these different approaches and compares their strengths and weaknesses.     

Ecological integration of alien species into a tree-parasitic fungus network

The diversification of species and their interactions during the course of evolution has produced ecological networks with a complex topology. This topology influences the current functioning of ecosystems. It is therefore important to investigate whether the species introduced recently by human activities have merged seamlessly into recipient ecological networks by developing interactions quantitatively and qualitatively similar to those of native species, or whether their establishment has altered the topology of the networks. We tackled this issue in the case of a well resolved interaction network between 51 forest tree taxa and 154 pathogenic fungal species. We found that alien and native species with similar phylogenetic histories and life-history strategies had similar types and numbers of interactions. Our results also suggest that the clustered architecture of the network has not been altered by the integration of alien species. It therefore seems that a few centuries have been sufficient for the network to assimilate the newly introduced species. This rapid integration was unexpected for a plant-pathogen network, because selection acts continually on plants, favouring the emergence of defences against new pathogens and impeding the development of new interactions. However, it was recently shown that perturbation of the structure of ecological networks might be overlooked if species interactions are not quantified. The tree-parasitic fungus network considered in this study is binary. We might therefore end up with different results by using quantitative data.     

A new synthetic methodology for tiazofurin

A new synthesis of tiazofurin is described from 2,3-O-isopropylidene-5-O-benzoyl-beta-D-ribofuranosyl cyanide.     

Predicting and mapping the risk of introduction of marine non-indigenous species into Great Britain and Ireland

Non-indigenous species (NIS) can have adverse environmental, economic and social impacts. Their management is now incorporated into key legislation, including the European Union (EU) Marine Strategy Framework Directive and the EU Regulation on the prevention and management of the introduction and spread of invasive alien species. Prevention of NIS introductions and the early detection of NIS following their introduction are recognised as the most effective approaches for reducing the potential impacts of NIS. This is true for most aquatic environments but especially so for the marine environment, where control and/or eradication are often not achievable. By assessing introduction vector activity, it is possible to identify coastal areas and specific locations where marine NIS may be more likely to be introduced. This study uses data relating to the activity of key introduction vectors; shipping, recreational boating and live animal aquaculture import, to estimate the relative risk of introduction of NIS around coastal regions of Great Britain and Ireland. Spatial analysis was used to create “heat” maps indicating coastal areas of increased relative risk of introduction of NIS by these vectors. The results of the present study will be crucial for the implementation of targeted vector management plans, supporting preventive strategies, and will facilitate a risk analyses of NIS threats to inform monitoring and surveillance programmes.     

Ecological restoration of aquatic and semi-aquatic ecosystems in the Netherlands: an introduction*

Hydrobiologia - In 1989, a symposium was held under the title `Netherlands-Wetlands', aiming at the presentation of the state of the art of the existing knowledge of structure and functioning...     

Candida species: new insights into biofilm formation

Biofilms of Candida albicans, Candida parapsilosis, Candida glabrata and Candida tropicalis are associated with high indices of hospital morbidity and mortality. Major factors involved in the formation and growth of Candida biofilms are the chemical composition of the medical implant and the cell wall adhesins responsible for mediating Candida-Candida, Candida-human host cell and Candida-medical device adhesion. Strategies for elucidating the mechanisms that regulate the formation of Candida biofilms combine tools from biology, chemistry, nanoscience, material science and physics. This review proposes the use of new technologies, such as synchrotron radiation, to study the mechanisms of biofilm formation. In the future, this information is expected to facilitate the design of new materials and antifungal compounds that can eradicate nosocomial Candida infections due to biofilm formation on medical implants. This will reduce dissemination of candidiasis and hopefully improve the quality of life of patients.     

Evolutionary genetics: jumping into a new species

A new study finds a dramatic increase in transposable element numbers in three new sunflower hybrid species, and may suggest a novel role for transposable elements in speciation.     

Optimization of carbon and nitrogen sources and growth factors for the production of an aquaculture probiotic (Pseudomonas MCCB 103) using response surface methodology

AIM: To develop a new medium for enhanced production of biomass of an aquaculture probiotic Pseudomonas MCCB 103 and its antagonistic phenazine compound, pyocyanin. METHODS AND RESULTS: Carbon and nitrogen sources and growth factors, such as amino acids and vitamins, were screened initially in a mineral medium for the biomass and antagonistic compound of Pseudomonas MCCB 103. The selected ingredients were further optimized using a full-factorial central composite design of the response surface methodology. The medium optimized as per the model for biomass contained mannitol (20 g l(-1)), glycerol (20 g l(-1)), sodium chloride (5 g l(-1)), urea (3.3 g l(-1)) and mineral salts solution (20 ml l(-1)), and the one optimized for the antagonistic compound contained mannitol (2 g l(-1)), glycerol (20 g l(-1)), sodium chloride (5.1 g l(-1)), urea (3.6 g l(-1)) and mineral salts solution (20 ml l(-1)). Subsequently, the model was validated experimentally with a biomass increase by 19% and fivefold increase of the antagonistic compound. CONCLUSION: Significant increase in the biomass and antagonistic compound production could be obtained in the new media. SIGNIFICANCE AND IMPACT OF THE STUDY: Media formulation and optimization are the primary steps involved in bioprocess technology, an attempt not made so far in the production of aquaculture probiotics.     

Myoblast-mediated fusion-injection: a new technique for introduction of macromolecules specifically into living skeletal muscle cells

A new technique for the introduction of macromolecules specifically into living skeletal muscle cells has been developed by a modification of the red blood cell ghost-mediated fusion-injection technique [M. Furusawa (1980) Int. Rev. Cytol. 62, 29-67]. Fluorescein-labeled bovine serum albumin (FITC-BSA) was introduced into chicken skeletal muscle myoblasts by the human red blood cell-mediated fusion-injection method in the presence of polyethylene glycol. Myoblasts loaded with FITC-BSA were then purified by a fluorescence cell sorter and cocultured with myotubes. Specific cell fusion between myoblasts and myotubes occurred under normal culture conditions and BSA was successfully introduced into living myotubes. This technique may provide a new method not only for the study of a given macromolecule's function in living muscle cells but also for therapeutic purposes such as muscle-specific drug delivery.     

Gene flow and hybridization following introduction of Mus domesticus into an established population

Seventy-seven house mice ( Mus domesticus ) from Eday, Orkney were released into a long-established population on the Isle of May (56^o 12'N) in 1982. Introduced allozymes, mt and Y-chromosome DNA, and Robertsonian chromosomes spread rapidly, reaching approximate stability c . 3 years later at frequencies different to those in both parental populations. The hybrid population was morphometrically intermediate between the two parents. This is a preliminary summary only; full details will be published elsewhere.