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Production of chitin from shrimp shell powders using Serratia marcescens B742 and Lactobacillus plantarum ATCC 8014 successive two-step fermentation
Get PDFShrimp shell powders (SSP) were fermented by successive two-step fermentation of Serratia marcescens B742 and Lactobacillus plantarum ATCC 8014 to extract chitin. Taguchi experimental design with orthogonal array was employed to investigate the most contributing factors on each of the one-step fermentation first. The identified optimal fermentation conditions for extracting chitin from SSP using S. marcescens B742 were 2% SSP, 2 h of sonication time, 10% incubation level and 4 d of culture time, while that of using L. plantarum ATCC 8014 fermentation was 2% SSP, 15% glucose, 10% incubation level and 2 d of culture time. Successive two-step fermentation using identified optimal fermentation conditions resulted in chitin yield of 18.9% with the final deproteinization (DP) and demineralization (DM) rate of 94.5% and 93.0%, respectively. The obtained chitin was compared with the commercial chitin from SSP using scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FT-IR) and X-ray diffraction (XRD). Results showed that the chitin prepared by the successive two-step fermentation exhibited similar physicochemical and structural properties to those of the commercial one, while significantly less use of chemical reagents.Keywords: Shrimp shell powders, Successive two-step fermentation, Serratia marcescens B742, Chitin, Lactobacillus plantarum ATCC 801
ASLC_Guide_to_Marine_Life_08.pdf
No full textThe purpose of this book is to
provide you with a bit more information about the organisms maintained at the ASLC so that you
may deepen your understanding and appreciation of them.
However, as a prelude to the more species-specific information contained in this document, there
are three short chapters that explain more basic topics such as what criteria constitute living
organisms, the basis for classification of living organisms, and the characteristics of a marine
ecosystem. Reading these chapters should help to place the more species-oriented information
(which can get quite detailed) into the broader frameworks of general and marine biology.
Chapters IV through XVIII are descriptions of various phyla (e.g., Mollusks, Echinoderms, and
Chordates) and/or species within those phyla that are maintained at the ASLC.
In addition, a glossary, defining many of the less familiar, more biologically-oriented terms
appears at the end of this handbook. When seen for the first time in the regular text of this
handbook, such terms are presented in boldface type (the word domain, just immediately above,
is an example.
Effects of supercritical fluid treatments on physical properties of wood-based composites
Get PDFThe effects of supercritical fluid (SCF) impregnation on physical properties of composites were investigated at various pressures, temperatures, and treatment times with carbon dioxide as the fluid and tebuconazole as a biocide. In general, within the ranges tested, SCF treatment had no negative effects on modulus of rupture (MOR), modulus of elasticity (MOE), or dimensional stability of particleboard, flakeboard, or medium-density fiberboard; in some instances, SCF treatment appeared to be associated with slight property improvements in some panel types. Shear tests of plywood suggested a similar lack of treatment effect. Results indicate that, despite the elevated pressure employed during the process, SCF impregnation does not adversely affect the mechanical properties of various wood-based composites.Keywords: particleboard, supercritical fluid, SCF, strength properties, tebuconazole, plywood, flakeboard, composites, preservative treatment, medium-density fiberboar
Motivations and Needs of Consumers of Fresh Seafood Products in France: New Opportunities and Marketing Strategies
Get PDFSince 2004, the French fishery field has had to cope with a levelling off of
consumption of fresh seafood products whereas the consumption of processed seafood
products is increasing. Nowadays, consumers prefer easier products: fresh deli products,
easy to cook or ready to consume. Therefore, fresh seafood products do not seem to
fulfil current consumer demand intrinsically (aspect, taste) and extrinsically (cooking
methods, use, origin, brand and price). In order to understand the evolution of
behaviour, motivation and consumers’ needs, several behavioural studies have been
conducted within the COGEPECHE research programme. In our article we focus on
three of them: focus groups, trade off and cognitive map.
This study has been carried out using an innovative methodology. First, focus groups
were organized to evaluate cognitive, emotional and prospective behaviours. Then, the
drivers and discriminate criteria of purchasing behaviour were analysed by the trade off
method. A cognitive map was created in order to understand consumer expectations
when purchasing seafood.
Such association allowed us to highlight consumers’ purchasing criteria (price,
freshness). However, dissonances have been shown between consumers’ declarations
and their behaviour. As a whole, these methods have pointed out the lack of consumers’
knowledge about seafood products. Five general motives for seafood choices have been
noted: safety, pleasure, health, convenience and ethics.Keywords: Consumer Behavior, Markets and Trade, Fisheries EconomicsKeywords: Consumer Behavior, Markets and Trade, Fisheries Economic
Determining in-channel (dead zone) transient storage by comparing solute transport in a bedrock channel–alluvial channel sequence, Oregon
Get PDFCurrent stream tracer techniques do not allow separation of in-channel dead zone (e.g., eddies) and out-of-channel (hyporheic) transient storage, yet this separation is important to understanding stream biogeochemical processes. We characterize in-channel transient storage with a rhodamine WT solute tracer experiment in a 304 m cascade-pool-type bedrock reach with no hyporheic zone. We compare the solute breakthrough curve (BTC) from this reach to that of an adjacent 367 m alluvial reach with significant hyporheic exchange. In the bedrock reach, transient storage has an exponential residence time distribution with a mean residence time of 3.0 hours and a ratio of transient storage to stream volume of 0.14, demonstrating that at moderate discharge, bedrock in-channel storage zones provide a small volume of transient storage with substantial residence time. In the alluvial reach, though pools are similar in size to those in the bedrock reach, transient storage has a power law residence time distribution with a mean residence time of >100 hours (estimated at nearly 1200 hours) and a ratio of storage to stream volume of 105. Because the in-channel hydraulics of bedrock reaches are simpler than alluvial step-pool reaches, the bedrock results are probably a lower end-member with respect to volume and residence time, though they demonstrate that in-channel storage may be appreciable in some reaches. These results suggest that in-stream dead zone transient storage may be accurately simulated by exponential RTDs but that hyporheic exchange is better simulated with a power law RTD as a consequence of more complicated flow path and exchange dynamics.Keywords: residence time distribution, transient storage, dead zone, hyporheic exchange, H.J. Andrews Experimental Forest, bedrock channelKeywords: residence time distribution, transient storage, dead zone, hyporheic exchange, H.J. Andrews Experimental Forest, bedrock channe
SharptonThomasMicrobiologyExomeCaptureSaliva.pdf
No full textBACKGROUND: Targeted capture of genomic regions reduces sequencing cost while generating higher coverage by
allowing biomedical researchers to focus on specific loci of interest, such as exons. Targeted capture also has the
potential to facilitate the generation of genomic data from DNA collected via saliva or buccal cells. DNA samples
derived from these cell types tend to have a lower human DNA yield, may be degraded from age and/or have
contamination from bacteria or other ambient oral microbiota. However, thousands of samples have been previously
collected from these cell types, and saliva collection has the advantage that it is a non-invasive and appropriate for a
wide variety of research.
RESULTS: We demonstrate successful enrichment and sequencing of 15 South African KhoeSan exomes and 2 full
genomes with samples initially derived from saliva. The expanded exome dataset enables us to characterize genetic
diversity free from ascertainment bias for multiple KhoeSan populations, including new exome data from six HGDP
Namibian San, revealing substantial population structure across the Kalahari Desert region. Additionally, we discover
and independently verify thirty-one previously unknown KIR alleles using methods we developed to accurately map
and call the highly polymorphic HLA and KIR loci from exome capture data. Finally, we show that exome capture of
saliva-derived DNA yields sufficient non-human sequences to characterize oral microbial communities, including
detection of bacteria linked to oral disease (e.g. Prevotella melaninogenica). For comparison, two samples were
sequenced using standard full genome library preparation without exome capture and we found no systematic
bias of metagenomic information between exome-captured and non-captured data.
CONCLUSIONS: DNA from human saliva samples, collected and extracted using standard procedures, can be used to
successfully sequence high quality human exomes, and metagenomic data can be derived from non-human reads.
We find that individuals from the Kalahari carry a higher oral pathogenic microbial load than samples surveyed in
the Human Microbiome Project. Additionally, rare variants present in the exomes suggest strong population structure
across different KhoeSan populations.Keywords: Exomes, Microbiome, Genetic diversity, KhoeSan, Metagenomic
Two-scale convergence of a model for flow in a partially fissured medium
Get PDFThe distributed-microstructure model for the flow of single phase
fluid in a partially fissured composite medium due to Douglas-Peszyńska-Showalter [12] is extended to a quasi-linear version. This model contains the
geometry of the local cells distributed throughout the medium, the flux exchange
across their intricate interface with the imbedded fissure system, and
the secondary flux resulting from diffusion paths within the matrix. Both the
exact but highly singular micro-model and the macro-model are shown to be
well-posed, and it is proved that the solution of the micro-model is two-scale
convergent to that of the macro-model as the spatial parameter goes to zero.
In the linear case, the effective coefficients are obtained by a partial decoupling
of the homogenized system.Keywords: microstructure, two-scale convergence, dual permeability, homogenization, fissured medium, modelin
Distant effect of assimilation of moored currents into a model of coastal wind-driven circulation off Oregon
Get PDFAn optimal interpolation (OI) sequential algorithm is implemented for a three-dimensional primitive equation model to assimilate current measurements from acoustic Doppler profilers moored on the Oregon shelf as a part of the Coastal Ocean Advances in Shelf Transport (COAST) upwelling experiment (May–August 2001). A stationary estimate of the forecast error covariance required by the OI is computed based on the error covariance in the model solution not constrained by data assimilation. Lagged model error covariances are used to account for the effect of previously assimilated data. The forecast error covariance has a shorter alongshore spatial scale than the model error covariance unconstrained by the data, as an effect of propagating dynamical modes. Assimilation of currents from one or two of the moorings located on the path of the upwelling jet helps to improve the model data rms error and correlation at the mooring sites located at an alongshore distance of 90 km, south or north from the assimilation sites. The coastal jet is deflected offshore over Heceta Bank, and assimilation of data from an inner-shelf mooring in the jet separation zone does not help to improve prediction in the far field. Larger improvements are obtained for the first part of the study period (yeardays 146–190). In the second part (days 191–237) the geometry of our limited area model possibly limits
prediction accuracy. In numerical experiments involving assimilation of data from only one mooring the actual and expected rms error improvements are compared, providing a consistency test for the forecast error covariance.Keywords: upwelling, coastal ocean prediction, data assimilationKeywords: upwelling, coastal ocean prediction, data assimilatio
Shelfbreak upwelling induced by alongshore currents: analytical and numerical results
Get PDFAlongshore flow in the direction of propagation of coastal trapped waves can result in upwelling at the shelfbreak. The intensity of this upwelling can be comparable in magnitude to wind-driven coastal upwelling, with its associated ecological features. Recent numerical experiments by Matano & Palma indicate that this upwelling results from convergence of Ekman transport at the shelfbreak. The mechanism for this phenomenon can be understood in terms of steady solutions to the shallow water equations in the presence of Coriolis force and bottom drag. Matano & Palma interpreted their numerical results in terms of the arrested topographic wave, but did not present direct comparisons. Here we present a family of analytical solutions to the equations of the arrested topographic wave that shows striking quantitative agreement with earlier numerical resultsThis is the publisher's version of record. The original submission is copyrighted by Cambridge University Press and can be found here: http://www.tos.org/Keywords: shallow water flows, ocean processes, topographic effectsKeywords: shallow water flows, ocean processes, topographic effect