Recent trends in nanomaterials immobilised enzymes for biofuel production

Application of nanomaterials as novel supporting materials for enzyme immobilisation has generated incredible interest in the biotechnology community. These robust nanostructured forms, such as nanoparticles, nanofibres, nanotubes, nanoporous, nanosheets, and nanocomposites, possess a high surface area to volume ratios that can cause a high enzyme loading and facilitate reaction kinetics, thus improving biocatalytic efficiency for industrial applications. In this article, we discuss research opportunities of nanoscale materials in enzyme biotechnology and highlight recent developments in biofuel production using advanced material supports for enzyme immobilisation and stabilisation. Synthesis and functionalisation of nanomaterial forms using different methods are highlighted. Various simple and effective strategies designed to result in a stable, as well as functional protein-nanomaterial conjugates are also discussed. Analytical techniques confirming enzyme loading on nanomaterials and assessing post-immobilisation changes are discussed. The current status of versatile nanomaterial support for biofuel production employing cellulases and lipases is described in details. This report concludes with a discussion on the likely outcome that nanomaterials will become an integral part of sustainable bioenergy production.     

Modern trends in perimetry

In this review of perimetry the subject is treated in two main sections. Part I discusses developments, particularly during the last thirty years, in classical clinical perimetry including the topics of kinetic and static perimetry, the use of multiple stimuli and the role of automation and objective techniques. Part II describes the development of various special techniques designed for more specific information about visual function. These include reference to the importance of controlling target illuminance, the value of spatial and temporal summation in perimetry and the use of coloured targets. The paper concludes by emphasizing the clinical value of routine field screening and the urgent need for standardization in perimetry.     

Precipitation of animal plasma proteins by puff-adder venom.

1. Plasma and serum samples obtained from various animals never previously exposed to snakes or snake venom were diffused against different concentrations of puff-adder, Bitis arietans, venom using the double immunodiffusion technique. 2. Depending upon venom concentration, two precipitin arcs could be produced in the case of all plasma samples used. No serum samples showed any arcs except pigeon serum, where one precipitin line was observed. 3. By altering the concentration of snake venom between 1% and 10% when immunodiffusing against plasma a change in position of the precipitin lines was observed and also the disappearance of one or both of the two bands at higher concentrations. This indicates that the arcs observed are in all probability due to precipitation of plasma protein fractions. 4. Previous results indicated that one of the two bands observed when diffusing venom against plasma was due to the precipitation of fibrinogen. By diffusing snake venom against heparin we have now shown that the second band involves this molecule and is not due to another coagulation factor as was suggested previously.     

Quantile regression estimates of animal population trends

Ecologists often estimate population trends of animals in time series of counts using linear regression to estimate parameters in a linear transformation of multiplicative growth models, where logarithms of rates of change in counts in time intervals are used as response variables. We present quantile regression estimates for the median (0.50) and interquartile (0.25, 0.75) relationships as an alternative to mean regression estimates for common density-dependent and density-independent population growth models. We demonstrate that the quantile regression estimates are more robust to outliers and require fewer distributional assumptions than conventional mean regression estimates and can provide information on heterogeneous rates of change ignored by mean regression. We provide quantile regression trend estimates for 2 populations of greater sage-grouse (Centrocercus urophasianus) in Wyoming, USA, and for the Crawford population of Gunnison sage-grouse (Centrocercus minimus) in southwestern Colorado, USA. Our selected Gompertz models of density dependence for both populations of greater sage-grouse had smaller negative estimates of density-dependence terms and less variation in corresponding predicted growth rates (λ) for quantile than mean regression models. In contrast, our selected Gompertz models of density dependence with piecewise linear effects of years for the Crawford population of Gunnison sage-grouse had predicted changes in λ across years from quantile regressions that varied more than those from mean regression because of heterogeneity in estimated λs that were both less and greater than mean estimates. Our results add to literature establishing that quantile regression provides better behaved estimates than mean regression when there are outlying growth rates, including those induced by adjustments for zeros in the time series of counts. The 0.25 and 0.75 quantiles bracketing the median provide robust estimates of population changes (λ) for the central 50% of time series data and provide a 50% prediction interval for a single new prediction without making parametric distributional assumptions or assuming homogeneous λs. Compared to mean estimates, our quantile regression trend estimates for greater sage-grouse indicated less variation in density-dependent λs by minimizing sensitivity to outlying values, and for Gunnison sage-grouse indicated greater variation in density-dependent λs associated with heterogeneity among quantiles.     

Modern problems of population genetics in animal husbandry

Summary Knowledge in animal husbandry derives from a complex of disciplines, and in this review the theory of one of these (population genetics) is discussed with regard to animal improvement, but with consideration of its implications in the other disciplines together with contributions from these to animal improvement programmes.The conventional programme for genetic improvement is outlined, but with particular emphasis placed on the lack of knowledge as to just what constitutes an adequate foundation population and what procedures will provide maximum total response to selection. An adequate foundation population is one containing as wide a sample as possible of the genetic variability existing in the species, and it is argued that genes of low initial frequency may comprise a significant proportion of the genetic variability available to selection. Further, a significant proportion of this variability may result from the segregation of a relatively small number of genes of large effect. The need for detailed information on the nature of gene action determining quantitative variation is emphasised.Maximisation of foundation population size is of prime importance, while the effective population size in subsequent generations of selection will largely determine total response to selection. Because of the restricted size of breeding programmes, selection responses will generally cease at less than the possible limit, so that methods of breaking through such apparent limits are discussed.In practical breeding programmes, a number of characters are generally under selection, and improvement then depends on genetic correlations among these characters. But to predict changes under selection, or to interpret those that have occurred, the basic causes of genetic correlations must be understood. Such understanding is further complicated by the possibility of change in magnitude or even direction of a genetic correlation during selection.Contributions from anatomy, physiology and animal behaviour are discussed in terms of information relevant to the definition of breeding objectives, optimum husbandry techniques, and limits to intensification in animal management. Artificial insemination has revolutionised dairy cattle breeding, and the development of techniques for oestrus synchronisation make more practical its use in other species. The implications of super-ovulation and egg transfer and modification of sex ratio on breeding programmes are considered, and the review concludes with a plea for information on the economics of breeding programmes.

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Zusammenfassung Grundlage der Entwicklung der Tierzüchtung sind die Erkenntnisse einer Reihe von Wissensgebieten. In der vorliegenden Übersicht wird über eine dieser Disziplinen, die Populationsgenetik, berichtet, und zwar speziell über die Theorie der Verbesserung von Leistungseigenschaften unter Einbeziehung anderer Disziplinen und ihrer Beiträge zum Tierzüchtungsprogramm.Es wird das konventionelle Programm für eine genetische Leistungssteigerung skizziert, aber mit besonderem Nachdruck darauf hingewiesen, daß keine genaue Kenntnis darüber besteht, was als angemessene Ausgangspopulation anzusehen ist und welche Maßnahmen den größten Selektionserfolg sichern. Eine angemessene Ausgangspopulation sollte die in der Spezies vorhandene genetische Variabilität im größtmöglichen Umfange enthalten, und es wird die Ansicht vertreten, daß Gene, die in der Ausgangspopulation mit geringer Frequenz vorhanden sind, doch einen signifikanten Anteil der einer Selektion zugänglichen genetischen Variablität ausmachen. Ein weiterer signifikanter Anteil dieser Variabilität dürfte aus der Spaltung einer relativ geringen Anzahl von Majorgenen herrühren. Die Notwendigkeit eingehender Unterrichtung über die Art der Genwirkung, welche die quantitative Variabilität bestimmt, wird betont.Es ist von primärer Wichtigkeit, die Ausgangspopulation so groß wie möglich vorzusehen, der Selektionserfolg in den folgenden Generationen wird wesentlich durch die vorhandene Populationsgröße bestimmt. Infolge der beschränkten Größe der Züchtungsprogramme erreicht die Selektion in der Regel nicht das Mögliche; Methoden zur Durchbrechung solcher Grenzen werden besprochen.In praktischen Züchtungsprogrammen wird im allgemeinen auf eine Reihe von Eigenschaften selektiert, die Leistungssteigerung hängt dann von den genetischen Korrelationen zwischen diesen Eigenschaften ab. Um aber durch Selektion zu bewirkende Veränderungen abschätzen oder aufgetretene erklären zu können, ist es notwendig, die Ursachen der genetischen Korrelation zu erkennen. Das wird durch die Möglichkeit von Stärke- oder sogar Richtungsänderungen der Korrelationen während der Selektion erschwert.Es wird schließlich über die Beiträge anderer Disziplinen, wie Anatomie, Physiologie, Verhaltensforschung, zur Festlegung der Zuchtziele, zu den besten Zuchttechniken und bezüglich der Grenzen einer Intensivierung der Tierhaltung berichtet. Die künstliche Besamung hat eine Revolution in der Rinderzüchtung bewirkt und durch die Entwicklung von Techniken zur Synchronisation des Geschlechtszyklus wird ihre Anwendung auch bei anderen Arten möglich. Es werden die Auswirkungen von Super-Ovulation und Ei-Übertragung sowie der Veränderungen des Geschlechtsverhältnisses behandelt. Die Übersicht schließt mit dem Ersuchen, daß auch über Fragen der Ökonomik von Züchtungsprogrammen informiert werden sollte.

     

Secular trends of annual morbidities of animal infectious diseases

Supposing two mathematical models, additive and multiplicative, the authors estimated the secular trends of annual morbidities (1949 approximately 1975) of twelve infectious diseases of domestic animals. For each diseases ten different trend curves were fitted. It was found that five regression equations, namely, those for bovine trichomoniasis, bovine tuberculosis, equine infectious anemia, pullorum disease in chickens, and foulbrood, gave the coefficient of determination of 97.9, 92.7, 91.0, 93.5, and 85.2%, respectively. Four of them were multiplicative, and the remaining one for equine infectious anemia was additive. From the viewpoint of practical utility, there was little doubt that even these secular trends might be used for predicting the relevant morbidities with fairly good preciseness.     

Large-scale trends in the evolution of gene structures within 11 animal genomes

We have used the annotations of six animal genomes (Homo sapiens, Mus musculus, Ciona intestinalis, Drosophila melanogaster, Anopheles gambiae, and Caenorhabditis elegans) together with the sequences of five unannotated Drosophila genomes to survey changes in protein sequence and gene structure over a variety of timescales—from the less than 5 million years since the divergence of D. simulans and D. melanogaster to the more than 500 million years that have elapsed since the Cambrian explosion. To do so, we have developed a new open-source software library called CGL (for “Comparative Genomics Library”). Our results demonstrate that change in intron–exon structure is gradual, clock-like, and largely independent of coding-sequence evolution. This means that genome annotations can be used in new ways to inform, corroborate, and test conclusions drawn from comparative genomics analyses that are based upon protein and nucleotide sequence similarities.     

Lignin-based polymers and nanomaterials

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Evolutionary trends in animal ribosomal DNA loci: introduction to a new online database

Ribosomal DNA (rDNA) loci encoding 5S and 45S (18S-5.8S-28S) rRNAs are important components of eukaryotic chromosomes. Here, we set up the animal rDNA database containing cytogenetic information about these loci in 1343 animal species (264 families) collected from 542 publications. The data are based on in situ hybridisation studies (both radioactive and fluorescent) carried out in major groups of vertebrates (fish, reptiles, amphibians, birds, and mammals) and invertebrates (mostly insects and mollusks). The database is accessible online at www.animalrdnadatabase.com. The median number of 45S and 5S sites was close to two per diploid chromosome set for both rDNAs despite large variation (1–74 for 5S and 1–54 for 45S sites). No significant correlation between the number of 5S and 45S rDNA loci was observed, suggesting that their distribution and amplification across the chromosomes follow independent evolutionary trajectories. Each group, irrespective of taxonomic classification, contained rDNA sites at any chromosome location. However, the distal and pericentromeric positions were the most prevalent (>?75% karyotypes) for 45S loci, while the position of 5S loci was more variable. We also examined potential relationships between molecular attributes of rDNA (homogenisation and expression) and cytogenetic parameters such as rDNA positions, chromosome number, and morphology.