bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metabolic Engineering of Pentose Phosphate Pathway in Ralstoniaeutropha for Enhanced Biosynthesis of Poly‐β‐hydroxybutyrate
Authors: Lee Jin‐Nam , Shin Hyun‐Dong , Lee Yong‐Hyun 
Published: October 2003

AbstractPoly‐β‐hydroxybutyrate (PHB) biosynthesis in Ralstonia eutrophafrom gluconate as a carbon source is carried out through the Entner‐Doudoroff (ED) pathway and the pentose‐phosphate (PP) pathway generating NADPH and glyceraldehyde‐3‐phosphate that flows to acetyl‐CoA, actively in the unbalanced PHB accumulation phase. The gnd gene encoding 6‐phosphogluconate dehydrogenase (6PGDH) and the tktA gene encoding the transketolase (TK) in PP pathway of E. coli were transformed into R. eutropha H16 to modify the metabolic flux of gluconate to the PHB biosynthesis. Over‐generated NADPH by the amplified gnd gene tended to depress the cell growth and PHB concentration. Meanwhile, the amplified tktA gene significantly increased both PHB biosynthesis and cell growth as a result of the effective flow of glyceraldehyde‐3‐phosphate into acetyl‐CoA along with the concomitant supplementation of NADPH. The amplified tktA gene also activated the enzyme activities directly associated with PHB biosynthesis. The transformant R. eutropha harboring tktA gene was cultivated using pH‐stat‐fed‐batch to achieve the overproduction of PHB.
Enzyme Distribution Derived from Macroscopic Particle Behavior of an Industrial Immobilized Penicillin‐G Acylase
Authors: Van Roon Jeroen L. , Joerink Michiel , Rijkers Marinus P. W. M. , Tramper Johannes , P. H. Schroën Catharina G. , Beeftink Hendrik H. 
Published: October 2003

AbstractThe macroscopic kinetic behavior of an industrially employed immobilized penicillin‐G acylase, called Assemblase, formed the basis for a discussion on some simple intraparticle biocatalytic model distributions. Assemblase catalyzes the synthesis of the widely used semisynthetic antibiotic cephalexin. Despite the obvious advantages of immobilization, less cephalexin and more of the unwanted byproduct d‐(–)‐phenylglycine are obtained due to diffusional limitations when the immobilized enzyme is employed. To rationally optimize Assemblase, the parameters particle size, enzyme loading, and enzyme distribution, which severely determine the macroscopic particle performance, were studied on the basis of macroscopic observations. Laser diffraction measurements showed that the particle sizes in Assemblase vary as much as 100‐fold. The relative and total enzyme loadings in Assemblase and fractions thereof of different sizes were determined by initial‐rate d‐(–)‐phenylglycine amide hydrolysis, cephalexin synthesis experiments, and active‐site titration. These experiments revealed that the loading of penicillin‐G acylase in Assemblase was inversely correlated with the particle diameter. Apart from enzyme loadings, estimates on the intraparticle enzyme distribution came from cephalexin synthesis experiments, where mass‐transport limitations were present. Although this method cannot provide the level of detail of specific labeling experiments, it is simple, fast, and cheap. Within the set of simple model predictions, a heterogeneous enzyme distribution with most biocatalyst present in the outer region of the particle (within the outer 100 μm) gave the best description of the observed behavior, although no exact correlation was established. Highly detailed determination of intraparticle enzyme distributions must come from immunolabeling.
Cell Surface Display of Organophosphorus Hydrolase in Pseudomonasputida Using an Ice‐Nucleation Protein Anchor
Authors: Shimazu Mark , Nguyen Anne , Mulchandani Ashok , Chen Wilfred 
Published: October 2003

AbstractA surface anchor system derived from the ice‐nucleation protein (INP) from Pseudomonas syringe was used to localize organophosphorus hydrolase (OPH) onto the surface of Pseudomonas putida KT2440. Cells harboring the shuttle vector pPNCO33 coding for the INP‐OPH fusion were capable of targeting OPH onto the cell surface as demonstrated by whole cell ELISA. The whole cell activity of P. putida KT2440 was shown to be 10 times higher than those of previous efforts expressing the same fusion protein in Escherichia coli. The capability of expressing enzymes on the surface of a robust and environmentally benign P. putida KT2440 should open up new avenues for a wide range of applications such as in situ bioremediation.
Novel Fermentation Strategy for Enhancing Glycerol Production by Candidakrusei
Authors: Liu Hong‐Juan , Liu De‐Hua , Zhong Jian‐Jiang 
Published: October 2003

AbstractDuring the later stage of glycerol production by fermentation of Candida krusei, glycerol consumption by the strain was observed, although there was residual sugar in the medium. To enhance the final glycerol accumulation, a new fermentation strategy was developed by maintaining high activities of glycerol synthetic enzymes (i.e., glycerol‐3‐phosphate dehydrogenase (ctGPD) and glycerol‐3‐phosphatase (GPP)) for a relatively long period while conducting oxygen limitation at a later stage to inhibit the increase of another enzyme activity related to glycerol degradation (i.e., mitochondrial glycerol‐3‐phosphate dehydrogenase (mtGPD)). With oxygen limitation performed from 88 h, when ctGPD and GPP activities were already at a low level while mtGPD activity was increasing, the glycerol dissimilation was efficiently reduced. The final glycerol concentration reached 55.6 g/L, which was about 18% (96 h) and 30% (104 h) higher than control, and its productivity increased to 0.54 g/(L h). The proposed strategy based on cell physiology was proved useful to the glycerol fermentation process.
Attachment of Marine Sponge Cells of Hymeniacidon perleve on Microcarriers
Authors: Zhao Quanyu , Jin Meifang , G. Müller Werner E. , Zhang Wei , Yu Xingju , Deng Maicun 
Published: October 2003

AbstractToward the development of an in vitro cultivation of marine sponge cells for sustainable production of bioactive metabolites, the attachment characteristics of marine sponge cells of Hymeniacidon perleve on three types of microcarriers, Hillex, Cytodex 3, and glass beads, were studied. Mixed cell population and enriched cell fractions of specific cell types by Ficoll gradient centrifugation (6%/8%/15%/20%) were also assessed. Cell attachment ratio (defined as the ratio of cells attached on microcarrier to the total number of cells in the culture) on glass beads is much higher than that on Cytodex 3 and Hillex for both mixed cell population and cell fraction at Ficoll 15–20% interface. The highest attachment ratio of 41% was obtained for the cell fraction at Ficoll 15–20% interface on glass beads, which was significantly higher than that of a mixed cell population (18%). The attachment kinetics on glass beads indicated that the attachment was completed within 1 h. Cell attachment ratio decreases with increase in cell‐to‐microcarrier ratio (3–30 cells/bead) and pH (7.6–9.0). The addition of serum and BSA (bovine serum albumin) reduced the cell attachment on glass beads.
Improved Mammalian Expression Systems by Manipulating Transcriptional Termination Regions
Authors: Kim Dongjun , Kim Jeong Do , Baek Kwanghee , Yoon Yeup , Yoon Jaeseung 
Published: October 2003

AbstractHere we show that the transcriptional terminator element of human gastrin gene, which is the only element characterized to date in terms of its function in transcriptional termination, increases the transient expression levels of recombinant proteins. The expression of the β‐galactosidase gene was enhanced 3–4‐fold in HeLa cells by inserting the terminator element of human gastrin gene at the 3′‐side of the SV40 polyadenylation signal/cleavage site of the control vector (pSV‐β‐gal). This effect of the terminator element is orientation‐dependent but not cell‐specific since a similar enhancement of β‐galactosidase gene expression was detected in COS.M6 and CHO DG44 cells. The increased level of β‐galactosidase gene expression by the transcriptional terminator element of human gastrin gene turned out to arise from elevated cellular mRNA levels, suggesting that the terminator element stabilizes mRNA by enhancing proper 3′‐end processing of mRNA.
Size and Stability of Reconstituted Sesame Oil Bodies
Authors: Peng Chi‐Chung , Lin I‐Ping , Lin Ching‐Kuan , Tzen Jason T. C. 
Published: October 2003

AbstractOil bodies of sesame seeds comprise a triacylglycerol matrix, which is surrounded by a monolayer of phospholipids embedded with unique proteins, mainly structural proteins termed oleosins. Artificial oil bodies were successfully reconstituted with various compositions of triacylglycerols, phospholipids, and oil‐body proteins. The sizes of reconstituted oil bodies displayed a normal distribution with an average size proportional to the ratio of triacylglycerols to oil‐body proteins. Both thermostability and structural stability of reconstituted oil bodies decreased as their sizes increased, and vice versa. Proteinase K digestion indicated that oleosins anchored both native and reconstituted oil bodies via their central hydrophobic domains. The stability of reconstituted oil bodies, as well as the purified ones from sesame seeds, could be substantially enhanced after their surface proteins were cross‐linked by glutaraldehyde or genipin.
Effects of stem fraction on the optimization of biomass allocation and maximum photosynthetic capacity
Authors: Osone Y. , Tateno M. 
Published: October 2003

SummaryA model was developed to examine effects of the stem biomass fraction on the optimal responses of plants to soil nitrogen availability.Our model predicts that the optimal leaf : root ratio and optimal photosynthetic capacity (Pmax) increase with soil N availability. For a given N availability, the optimal leaf : root ratio decreases and the optimalPmaxincreases with increasing stem fraction. As a result, the increase in optimal leaf : root ratio is smaller, and that in optimalPmaxis greater, in response to increasing N availability when stem fraction is large.To test these predictions we grew two herbs with different stem fractions:Polygonum cuspidatumSieb. et Zucc. andChenopodium albumL.Showing excellent agreement with the simulation results, the leaf N concentration and leaf : root ratio of the two herbs increased with increasing N availability, and leaf N concentration was larger forC. albumwith higher stem fraction thanP. cuspidatum.The general tendency for plants with larger stem fractions also to have greater leaf N concentrations andPmaxwas demonstrated for a wide range of temperate herbs. This suggests that stem fraction may be a source of variation inPmaxamong plants in the same functional group.
Effects of inbreeding on immune response and body size in a social insect, Bombus terrestris
Authors: Gerloff C. U. , Ottmer B. K. , Schmid‐Hempel P. 
Published: October 2003

Summary

Inbreeding can negatively affect various fitness components. Here we examine how immune response and body size of a social insect are affected by inbreeding, sex and ploidy.
In the bumble‐bee, Bombus terrestris (L.), the offspring of colonies resulting from brother–sister matings were compared with that of outbred colonies. Immune response was measured as the degree of encapsulation of a novel antigen, body size as the length of the radial cell in the forewings.
Inbreeding affected neither immune response nor body size in either workers or haploid males under laboratory conditions. However, fitness characteristics varied significantly among maternal families and colonies. The lack of detectable inbreeding depression for two fitness components might help explain why B. terrestris is a good colonizer in nature.
In addition, sex and ploidy strongly affected the fitness components studied: diploid males had a significantly lower immune response than haploid males, who in turn had a significantly lower immune response than workers of the same colony. The body size of diploid males was intermediate between the body size of workers and haploid males.
Detection of serum immunoglobulins in wild birds by direct ELISA: a methodological study to validate the technique in different species using antichicken antibodies
Authors: Martínez J. , Tomás G. , Merino S. , Arriero E. , Moreno J. 
Published: October 2003

Summary

This study presents an easy protocol to measure the amount of immunoglobulins from the blood serum of different bird species in the wild (Ficedula hypoleuca Pallas, Parus caeruleus L., Lanius meridionalis Temminkck, Lanius collurio L., Athene noctua Scopoli and Falco tinnunculus L.) by direct enzyme‐linked immunosorbent assay, ELISA using commercial antichicken antibodies.
Additionally, the ELISA technique is validated for detecting serum immunoglobulins by means of other electrophoretic (sodium dodecyl sulphate polyacrylamide gel electrophoresis, SDS‐PAGE, and native electrophoresis) and immunological (Western blot) methods.
The results by Western blot show that the commercial antibody recognized proteins with apparent molecular weight according to heavy and light chains of immunoglobulins.
Both ELISA and Western blot data were correlated, implying that the commercial antibody bound to immunoglobulins and not to other proteins or ELISA plates. Densitometric data achieved by SDS‐PAGE and native electrophoresis were only correlated in some species indicating a problem in detecting clearly the heavy and light chains, and γ‐globulin fraction, respectively.
It is concluded that the proposed protocol is easy to carry out and may be used to detect total serum immunoglobulins from most bird species.
Seed set and gene flow patterns in an experimental population of an endangered heterostylous herb with controlled local opposite‐morph density
Authors: Ishihama F. , Nakano C. , Ueno S. , Ajima M. , Tsumura Y. , Washitani I. 
Published: October 2003

SummarySeed reproduction of a plant species is strongly affected by the spatial structures of its population through gene flow patterns. We assessed the effects of the spatial arrangement of genetically compatible mates on the seed set and gene flow of a heterostylous perennial species,Primula sieboldiiE. Morren (Primulaceae), using a patchy experimental population.Seed set was significantly higher in patches containing opposite‐morph genets than in patches without opposite‐morph genets. Pollen flow within patches explained 76·9% of total pollen flow, while 13·5% was ascribed to pollen flow between patches. Mean and maximum pollen dispersal distances within the experimental population were 7·23 and 89 m, respectively.Mean and maximum seed dispersal distances were 10·4 and 23·0 cm, respectively.Our results suggest a profound effect of the spatial arrangement of compatible mates within the patchy population on seed set and gene flow. Investigations using experimental populations in combination with molecular markers will provide highly effective means for evaluating the influences of spatial structures on plant gene flow and reproduction, and will also provide valuable information for conservation efforts.
Does morphology or the size of the internal nitrogen store determine how Vaccinium spp. respond to spring nitrogen supply?
Authors: Grelet G.‐A. , Alexander I. J. , Millard P. , Proe M. F. 
Published: October 2003

Summary

Vaccinium myrtillus (deciduous) and V. vitis‐idaea (evergreen) are ericaceous shrubs adapted to low‐nitrogen environments. Their comparative responsiveness to N supply was determined in relation to both N storage and developmental constraints.
Plants were grown with high or low N in sand culture to condition their N storage, and their growth measured during the first flush of a second year when plants from each treatment were again supplied either high or low N. 15N‐labelling was used to quantify remobilization of N taken up in the first year for growth in the second.
In both species, the growth response to external N availability was mediated through a change in the number of buds, initially present, which produced shoots, with no alteration of the number of leaves per shoot; but the magnitude of the response was smaller in the evergreen species. The second flush of growth took place more rapidly in V. myrtillus than in V. vitis‐idaea, and depended on both external and internal N supply, in terms of the number of shoots produced and the number of leaves per shoot.
The amount of labelled N remobilized by both species depended on the level of N reserves, and on the number of initial buds which produced shoots. In V. myrtillus, the total amount of N remobilized to new growth was significantly affected by external N supply. Since the total amount of N remobilized is independent of external N availability during spring growth, this result implies that the age of the N remobilized depended on the number of buds that produced shoots. We explain this result by the perennial nature of N storage in V. myrtillus and the age range of the pool of buds coming into growth each year on an individual plant.
Nitrogen remobilization and the growth response to N supply were closely linked with the pattern of bud activation. Species‐specific growth responses to N supply in spring were better explained by developmental constraints on growth than by the ability to store and re‐use N.
Quantifying individual feeding variability: implications for mollusc feeding experiments
Authors: Hanley M. E. , Bulling M. T. , Fenner M. 
Published: October 2003

Summary

In order to quantify the level of variability in seedling consumption displayed by individual molluscs, we placed one snail (Helix aspersa) in each of 51 trays containing (7‐day‐old) Taraxacum officinale seedlings for 7 days.
Initially, individual snails displayed considerable variability in their consumption of seedlings; however, this variability declined with time. The consumption of seedlings was not related to individual snail mass.
A second grazing experiment, using five different snail densities in similar experimental conditions to the first, showed that increasing snail number reduced variability within treatment groups.
A computer simulation, based on data from the first experiment correctly predicted the basic form of the decline in feeding variability with increasing snail density found in the second. Post hoc changes to the model, based on empirical analysis of the second experiment to account for mutual interference, reduced discrepancies between empirical and model results.
This study highlights the consequences that individual feeding behaviour has on feeding trials with molluscs, and provides a simple method by which this variability can be quantified and accommodated within experimental design.
Influence of acclimation and incubation medium on supercooling by hatchling painted turtles, Chrysemys picta
Authors: Packard G. C. , Packard M. J. 
Published: October 2003

Summary

Baby Painted Turtles, Chrysemys picta (Schneider 1783), ingest soil and fragments of eggshell as they are hatching from their eggs. The ingested soil typically contains bacterial nucleating agents that can cause water in the gut to freeze at high subzero temperatures. If ice forms in the gut, however, the crystals penetrate the wall of that organ and cause water in body compartments to freeze. Thus, newly hatched turtles freeze spontaneously at high subzero temperatures owing to the nucleation of ice by bacteria in the gut.
Painted Turtles purge their gut of soil in the weeks after hatching, but removing particulate material from the GI tract does not, by itself, result in elimination of the bacterial nucleating agents. The purging of nucleating agents requires that hatchlings also be exposed to low (but non‐freezing) temperatures. The response to low temperature is completed in little more than 1 month; a longer exposure does not elicit a demonstrable improvement in the capacity for supercooling.
The limit of supercooling does not vary significantly among turtles hatching on different kinds of soil, despite the fact that different soils typically harbour different concentrations of nucleating agents. Thus, the risk of heterogeneous nucleation probably does not vary appreciably among turtles hatching and overwintering in different kinds of soil in the field.
Hatchling Painted Turtles that have become acclimatized to low temperatures in the field presumably have acquired a high resistance to freezing by inoculation (as shown by prior study) and an enhanced capacity for supercooling (current study), thereby enabling many animals to withstand exposure to ice and cold during winter by remaining unfrozen and supercooled.
A critique of the Diagnostic Criteria for Psychiatric Disorders for Use with Adults with Learning Disabilities/Mental Retardation (DC‐LD) chapter on non‐affective psychotic disorders
Authors: Melville Craig A. 
Published: October 2003

AbstractBackground  There has been a longstanding interest in the study of psychotic disorders in adults with intellectual disability. The DC‐LD chapter for non‐affective psychotic disorders provides operationalised criteria for use with this population.Methods  A detailed, structured review of the literature was carried out. Relevant papers were reviewed to provide a framework for a critique of the DC‐LD criteria.Results  Most of the research literature focuses on psychotic disorders in adults with mild intellectural disability and suggests that this group experience clinical symptoms similar to those experienced by adults with average abilities. Although the DC‐LD criteria for non‐affective psychotic disorders are derived from the ICD‐10 equivalent categories they are broader than other classification systems, which may affect their reliability, validity and utility.Conclusions  At this stage, it is important that the DC‐LD criteria are used alongside established systems to gather information about their use for clinical and research purposes.
Psychiatric diagnosis, intellectual disabilities and Diagnostic Criteria for Psychiatric Disorders for Use with Adults with Learning Disabilities/Mental Retardation (DC‐LD)
Authors: Cooper Sally‐Ann , Melville Craig A. , Einfeld Stewart L. 
Published: October 2003

AbstractBackground  Classification of psychopathology using operationalized diagnostic criteria is one component of psychiatric assessment. Previous literature has demonstrated that there are limitations in the International Classification of Diseases−10 (ICD‐10) and the Diagnostic and Statistical Manual–IV (DSM‐IV) when used with adults with intellectual disabilities.Methods  A literature search using Medline, PsychLIT and hand searching of key journals identified the existing literature, which was reviewed by the Diagnostic Criteria for Psychiatric Disorders for Use with Adults with Learning Disabilities/Mental Retardation (DC‐LD) Development Working Group. Key findings are integrated into this paper. This, together with expert consensus led to the development of DC‐LD, a new psychiatric classificatory system devised specifically for use with adults with intellectual disabilities. The new diagnostic criteria and classification within DC‐LD were piloted with 52 field investigators drawing on 709 clinical cases. Validity of DC‐LD classification was measured by comparison between the criteria providing DC‐LD diagnosis and the gold standard of learning disabilities psychiatric assessment.Results  In 96.3% of cases, the DC‐LD diagnosis was fully concordant with that of clinical opinion. The few discrepancies related to level of detail.Conclusion  DC‐LD accommodates the pathoplastic effect of intellectual disabilities on psychopathology. Its use will hopefully improve clinical practice and facilitate research, but further work to determine its usefulness and limitations is required.