bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic analysis of some flowering time and adaptive traits in wheat
Authors: LAW C. N. , WORLAND A. J. 
Published: March 2003

summaryThe present understanding of the genetic control of flowering in wheat is reviewed. Although this information will continue to be of value in breeding and in recognizing the role such genes have had in adapting the wheat crop to global agriculture, its use in denning the processes responsible for flowering will be limited. Progress here will depend on developments in model plant systems such as Arabidopsis, where methods for isolating genes are much more advanced than in wheat. These developments, which have already started, will probably be used to establish homologies between the genes for flowering within the cereals, as well as more widely. An understanding of the flowering process in wheat is likely to emerge from this approach. In the meantime, there are some unknowns in the genetics of flowering in wheat which need to be resolved. These include the identification of a gene(s) on the group 4 chromosomes of wheat which is homoeoallelic with the gene Sh in barley. Also, the proposed gene(s) delaying flowering and located on the group 6 chromosomes needs to be recognized and mapped. Similar needs occur for the group 1 chromosomes as well as the resolution of whether or not Vrn5 is correctly positioned on chromosome 7BS.
Relationships between relative water content and growth parameters under water stress in barley: a QTL study
Authors: TEULAT B. , MONNEVEUX P. , WERY J. , BORRIES C. , SOUYRIS I. , CHARRIER A. , THIS D. 
Published: March 2003

summaryDrought strongly affects cereal yield in several regions of the world. Plant growth and plant water status in response to soil water deficit play an important role in tolerance to drought and in yield stability. In order to investigate the relationship between plant growth and water relations, 187 barley (Hordeum vulgare L.) recombinant inbred lines from a cross between two Mediterranean varieties, Tadmor and Er/Apm, were studied in a growth chamber for RWC, number of leaves on the main tiller (NL), number of tillers (NT) and total shoot fresh and dry biomass (TSFM and TSDM). Measurements were made at the beginning of tillering on well watered plants and at a soil moisture content of 14% of field capacity. A negative phenotypic correlation between RWC and growth parameters was obtained in both treatments. Under water stress, a negative genetic correlation was also found between the same characters. QTLs involved in RWC, NL and TSFM variation were positioned on a RFLP‐RAPD genetic map. Different DNA regions involved in constitutive and water stress responses were detected. In the stress treatment, one region on chromosome 1 was involved in RWC and NL variation giving a genetic basis to the phenotypic correlations found. Separated map positions were also found for RWC and NL. Epistatic interactions between several QTLs and between QTLs and other markers were detected only in the water stress treatment, suggesting that some chromosomal regions might be involved in the regulation of the expression of the traits under water stress. This work suggested that even if some parameters are strongly correlated, finding QTLs for only one trait is not sufficient to detect all the candidate regions which might be involved in the control of the correlated traits. The results of localization and co‐localization of QTLs are physiologically interpreted.
Mycorrhizal formation by Paxillus involutus strains in relation to their IAA‐synthesizing activity
Authors: RUDAWSKA M. L. , KIELISZEWSKA‐ROKICKA B. 
Published: March 2003

summaryIAA production by the ectomycorrhizal fungus Paxillus invotutus grown in pure culture was investigated by testing IAA accumulation or IAA‐synthesizing activity. All the Paxillus involutus strains studied released indole compounds either when incubated with 0.5 mM tryptophan or in its absence. HPLC analyses of indole compounds all yielded two main peaks identified by reference to controls as being IAA and indole‐3‐carboxylic acid and a small peak of indole‐3‐aldehyde. Mass spectrometry unequivocally confirmed IAA production in the culture filtrates and in the incubation solution used to study in vitro IAA‐synthesizing activity. The IAA‐synthesizing activity was found to vary widely, from 7.6 to 137.4 nmol IAA h−1 g−1 f. wt, between strains. The mycorrhizal activity of these strains with seedlings of Pinus sylvestris cultured under aseptic conditions was tested. Fungal strains that were characterized in pure culture conditions by high LAA‐synthesizing activity induced more fine roots and significantly higher numbers of mycorrhizas than strains which showed a low activity of IAA synthesizing enzymes. The increased ectomycarrhiza formation was generally accompanied by an increased growth of seedlings.
Ozone‐induced accumulation of carbohydrates changes enzyme activities of carbohydrate metabolism in birch leaves
Authors: EINIG W. , LAUXMANN U. , HAUCH B. , HAMPP R. , LANDOLT W. , MAURER S. , MATYSSEK R. 
Published: March 2003

summaryBirch cuttings (Betula pendula Roth) were grown in a sand‐culture system with two concentrations (0.05, HF and 0.005%, LF) of fertilizer containing macronutrients and micronutrients, and were exposed to 90/40 nl 1−1 O3(day/night) and < 3 nl 1−1 O3 (control) for one growing season in the field fumigation chambers at Birmensdorf (Switzerland). Leaves of different ages were analysed for gas exchange, contents of chlorophyll, protein, and for metabolites as well as enzyme activities of carbohydrate metabolism.Ozone reduced net photosynthesis and chlorophyll contents in mature leaves of both fertilization treatments, whereas that of protein was only reduced in high‐fertilized plants (HF). However, net photosynthesis, chlorophyll, and protein increased in young leaves of low‐fertilized plants (LF). The effects of ozone on enzyme activities of carbohydrate metabolism were most pronounced in leaves of LF plants. Specific activities of the sucrose‐cleaving enzymes, sucrose synthase and alkaline invertase, were induced, whereas acid invertase was unchanged. Extractable activity of sucrose phosphate synthase, which is a key enzyme of sucrose synthesis, was reduced. Levels of fructose 2,6‐bisphosphate, an inhibitor of sucrose synthesis, were increased in leaves of O3/LF plants, but reduced in O3/HF plants. In addition, activities of enzymes involved in starch metabolism, ADP‐glucose pyrophosphorylase and starch phosphorylase, were lowered in ozone‐treated samples and the ratio of ATP: ADP was increased.It is concluded that chronic ozone exposure leads to an inhibition of sucrose synthesis and favours sucrose degradation. This effect is modulated by the nutrient status of the plants, indicating higher O3 tolerance in HF plants. Furthermore, as the metabolic responses in the ozone‐treated samples resemble very closely those observed under end‐product inhibition of photosynthesis, we assume that the O3 effect is mainly due to reduced photosynthate export.
Allometric determination of tree growth in a CO2‐enriched sweetgum stand
Authors: Norby Richard J. , Todd Donald E. , Fults Jason , Johnson Dale W. 
Published: March 2003

Summary

In a free‐air CO2 enrichment (FACE) study, above‐ground growth of Liquidambar styraciflua (sweetgum) trees was measured in a closed‐canopy stand to test hypotheses about long‐term effects of rising [CO2] in a deciduous forest.
Allometric relationships were established between above‐ground dry mass and basal area, height, taper and wood density for all trees in the 314‐m2 plots. Leaf area index was calculated from leaf litter mass.
In the first year of exposure, elevated [CO2] stimulated stand‐level aboveground dry matter increment by 33%, but in the second year the growth stimulation was reduced to 15% and was no longer statistically significant. Leaf area index was not affected by CO2 enrichment in either year.
These results indicate that large trees that are no longer in an exponential growth phase retain the capacity to respond to elevated [CO2]. The combined 2‐yr response of a 24% increase in growth per unit leaf area is consistent with predictions from earlier studies. A longer‐term data set is needed to resolve the reason for different responses in the 2 years.
Flooding‐tolerant legume symbioses from the Brazilian Pantanal
Authors: James EuaN. K. , Loureiro M. de Fatima , Pott Arnildo , Pott ValI. J. , Martins Claudia M. , Franco Avilio A. , Sprent Janet I. 
Published: March 2003

Summary

Nodulated legumes in some of the flooded and seasonally flooded areas of the Pantanal Mato‐Grossense wetlands in Brazil are described here.
In the permanently flooded lakes (baias) of the Caracara national park Discolobium pulchellum, Mimosa pellita, Sesbania exasperata and Vigna lasiocarpa (syn. Phaseolus pilosus) were the most abundant, whereas close to Corumbá, at the edges of the river Paraguai, Neptunia spp. were also common. Adaptations that allow these legumes to fix N2 in a flooded environment included a floating growth habit, aerenchyma and nodulated adventitious roots.
By contrast, Aeschynomene spp. (A. ciliata, A. denticulata, A. fluminensis, and A. sensitiva) were the dominant nodulated legumes in the seasonally flooded pastures of Nhumirim.
Stem‐nodulation was commonly observed, particularly on seasonally flooded Aeschynomene and seasonal/permanently flooded Discolobium spp., but also, in a modified form, on floating stems of V. lasiocarpa. The structures of stem and/or root nodules on Aeschynomene spp., Discolobium leptophyllum and V. lasiocarpa are described in detail, and nodulation by D. leptophyllum and Neptunia pubescens is reported for the first time.
Protein tyrosine phosphatases in higher plants
Authors: Luan Sheng , Ting Julie , Gupta Rajeev 
Published: March 2003

SummaryReversible protein phosphorylation is the most common mechanism for cellular regulation in eukaryotic systems. Indeed, approximately 5% of the Arabidopsis genome encodes protein kinases and phosphatases. Among the thousands of such enzymes, only a small fraction has been examined experimentally. Studies have demonstrated that Ser/Thr phosphorylation and dephosphorylation play a key role in the regulation of plant physiology and development. However, function of tyrosine phosphorylation, despite the overwhelming importance in animals, has not been systematically studied in higher plants. As a result, it is still controversial whether tyrosine phosphorylation is important in plant signal transduction. Recently, the first two protein tyrosine phosphatases (PTPs) from a higher plant were characterized. A diverse group of genes encoding putative PTPs have been identified from the Arabidopsis genome sequence databases. Genetic analyses of various PTPs are underway and preliminary results have provided evidence that these PTPs serve critical functions in plant responses to stress signals and in plant development.
Mycorrhizas and nutrient cycling in ecosystems – a journey towards relevance?
Authors: Read D. J. , Perez‐Moreno J. 
Published: March 2003

SummaryProgress towards understanding the extent to which mycorrhizal fungi are involved in the mobilization of nitrogen (N) and phosphorus (P) from natural substrates is reviewed here. While mycorrhiza research has emphasized the role of the symbiosis in facilitation of capture of these nutrients in ionic form, attention has shifted since the mid‐1980s to analysing the mycorrhizal fungal abilities to release N and P from the detrital materials of microbial faunal and plant origins, which are the primary sources of these elements in terrestrial ecosystems. Ericoid, and some ectomycorrhizal fungi have the potential to be directly involved in attack both on structural polymers, which may render nutrients inaccessible, and in mobilization of N and P from the organic polymers in which they are sequestered. The advantages to the plant of achieving intervention in the microbial mobilization–immobilization cycles are stressed. While the new approaches may initially lack the precision achieved in studies of readily characterized ionic forms of N and P, they do provide insights of greater ecological relevance. The results support the hypothesis that selection has favoured ericoid and ectomycorrhizal systems with well developed saprotrophic capabilities in those ecosystems characterized by retention of N and P as organic complexes in the soil. The need for further investigation of the abilities of arbuscular mycorrhizal fungi to intervene in nutrient mobilization processes is stressed.
Relationship between the curriculum system and the understanding of nutritional terms in elementary school children
Authors: Suzuki Yoko , Rowedder Martha 
Published: March 2003

AbstractTo clarify the relation between the curriculum system and the understanding of nutrition terms, 944 students aged 8–12 years living in Japan, the USA and the UK, were asked about the recognition, medium for recognition, and understanding of nutrition terms. The effect of nutrition education from an early stage in elementary schools in the UK and the USA was confirmed. These results suggest the possibility of beginning nutrition education earlier in the elementary school in Japan. American students had paid attention to food labels. These results showed that a learning and teaching strategy founded on comprehensively based subjects in the USA had influenced good behaviour for dietary life. On the other hand, there was not a relationship between an understanding of nutrition terms and a developmental stage. Many students in three countries were influenced by television commercials to buy candy or soda. We think that it is important to develop a curriculum that includes practical learning and ensures hours of teaching for the purpose of acquirement of nutritional knowledge. It is also necessary to encourage critical thinking skills to evaluate television commercial messages through school lessons.
Furosine content, loss of o‐phthaldiadehyde reactivity, fluorescence and colour in stored enteral formulas
Authors: Rufián‐Henares J A , García‐Villanova B , Guerra‐Hernández E 
Published: March 2003

Heat effects induced during the storage of enteral formula under laboratory and industrial conditions were evaluated using the following indicators: furosine; loss of available amino groups, measured by decrease in o‐phthaldialdehyde (OPA) reactivity; fluorescence associated with the Maillard reaction (345 nm excitation, 415 nm emission); and colour (absorbance at 420 nm). The storage of formulas A and B (with different protein content) at 4, 20 and 30°C during 12, 24 and 36 weeks produced an increase in furosine values. Under industrial storage conditions at 55°C for between 1 and 12 weeks the behaviour of furosine differed between the two types of formulas. In Formula A (lesser protein content), there was a decrease in furosine level after the third week, whereas in formula B (greater protein content) a decrease was observed after the eighth week.The loss of OPA reactivity reached 18% and 22%, respectively, for formula B and formula A stored at 30°C for 36 weeks. In adverse storage conditions (55°C), the loss of OPA reactivity reached 50%.Fluorescence intensity (FI) and absorbance at 420 nm increased at all time/temperatures assayed. It reached values of 22.5 and 27.5 for FI and 0.161 and 0.173 for A420, respectively, for formula A and B, stored for 36 weeks at 30°C.Furosine, loss of OPA reactivity, fluorescence intensity and colour are useful indicators of nonenzymatic browning during storage of enteral formulas.
Influence of milk‐clotting enzymes on acidification rate of natural whey starter culture
Authors: Meinardi C A , Alonso A A , Hynes E R , Zalazar C A 
Published: March 2003

The aim of this work was to study the influence of milk‐clotting enzymes on whey starter culture and hard cheesemaking. Four cheeses were prepared simultaneously per cheesemaking day, and the experiment repeated on eight consecutive days. Adult bovine rennet was used in the control cheeses, and three formulations of fermentation‐produced chymosin (FPC) in the experimental cheeses. Whey cultures were obtained from the whey of the preceding cheeses, incubated individually for 24 h at 42°C. pH values of the control and experimental whey did not differ significantly before incubation, but after 24 h incubation the pH of the FPC whey was significantly higher than that of the control. Soluble nitrogen content in trichloroacetic acid 2% and 12% and in phosphotungstic acid 2.5% was significantly lower for all experimental whey samples than for control whey. This probably explains the decrease in the acidification rate of the whey cultures when bovine coagulant is replaced by FPC in hard cheesemaking.
Optimization of ingredients for the manufacture of soft‐serve ice‐cream (Softy) by response surface methodology (RSM)
Authors: Sharma H K , Prasad K , Jindal S , Sood P , Pandey H 
Published: March 2003

Soft ice‐cream samples were prepared with different proportions of cream and skimmed milk powder (SMP) and were examined for quality by physico‐chemical parameters and sensory attributes. The specific proportions of cream and SMP were designed using the central composite rotatable design (CCRD). Response surface analysis indicated that sensory flavour, texture and overall acceptability (OAA) scores of soft ice‐cream varied from 7.12 to 8.86, 6.66 to 8.03 and 6.90 to 8.45, respectively. The differences in the sensory scores for respective attributes were highly significant (P ≤ 0.01). The soft ice‐cream containing a minimum level of 3.24% cream and 4.94% SMP resulted in a product having a minimum of 4.3% fat, 5.7% lactose and 33% total solids, with a minimum OAA score of 8. The derived mathematical second‐order polynomial models against cream (X) and SMP (Y) were found to be adequate as coefficients of multiple determinants (R2) were more than 80% except for melting resistance.
Viability of Salmonella enterica subsp. enterica during the preparation and cold storage of Egyptian soft cheeses and ice‐cream
Authors: Nassib Taha A , Zin El‐Din Mohamed , El‐Sharoud Walid M 
Published: March 2003

Changes occurring in the viability of Salmonella enterica subsp. enterica during the preparation and cold storage of Domiati cheese, Kariesh cheese and ice‐cream were examined. A significant decrease in numbers was observed after whey drainage during the manufacture of Domiati cheese, but Salmonella remained viable for 13 weeks in cheeses prepared from milks with between 60 and 100 g/L NaCl; the viability declined in Domiati cheese made from highly salted milk during the later stages of storage. The method of coagulation used in the preparation of Kariesh cheese affected the survival time of the pathogen, and it varied from 2 to 3 weeks in cheeses made with a slow‐acid coagulation method to 4–5 weeks for an acid‐rennet coagulation method. This difference was attributed to the higher salt‐in‐moisture levels and lower pH values of Kariesh cheese prepared by the slow‐acid coagulation method. A slight decrease in the numbers of Salmonella resulted from ageing ice‐cream mix for 24 h at 0°C, but a greater reduction was evident after one day of frozen storage at −20°C. The pathogen survived further frozen storage for four months without any substantial change in numbers.
IPF, a vesicular uptake inhibitory protein factor, can reduce the Ca2+‐dependent, evoked release of glutamate, GABA and serotonin
Authors: Tamura Yutaka , Özkan Eric D. , Bole David G. , Ueda Tetsufumi 
Published: March 2003

Synaptic vesicles in the nerve terminal play a pivotal role in neurotransmission. Neurotransmitter accumulation into synaptic vesicles is catalyzed by distinct vesicular transporters, harnessing an electrochemical proton gradient generated by V‐type proton‐pump ATPase. However, little is known about regulation of the transmitter pool size, particularly in regard to amino acid neurotransmitters. We previously provided evidence for the existence of a potent endogenous inhibitory protein factor (IPF), which causes reduction of glutamate and GABA accumulation into isolated, purified synaptic vesicles. In this study we demonstrate that IPF is concentrated most in the synaptosomal cytosol fraction and that, when introduced into the synaptosome, it leads to a decrease in calcium‐dependent exocytotic (but not calcium‐independent) release of glutamate in a concentration‐dependent manner. In contrast, α‐fodrin (non‐erythroid spectrin), which is structurally related to IPF and thought to serve as the precursor for IPF, is devoid of such inhibitory activity. Intrasynaptosomal IPF also caused reduction in exocytotic release of GABA and the monoamine neurotransmitter serotonin. Whether IPF affects vesicular storage of multiple neurotransmitters in vivo would depend upon the localization of IPF. These results raise the possibility that IPF may modulate synaptic transmission by acting as a quantal size regulator of one or more neurotransmitters.
Brain succinic semialdehyde dehydrogenase: identification of reactive lysyl residues labeled with pyridoxal‐5′‐phosphate
Authors: Choi Soo Young , Bahn Jae Hoon , Lee Byung Ryong , Jeon Seong Gyu , Jang Joong Sik , Kim Choong Kwon , Jin Li Hua , Kim Kyung Hee , Park Jin Sun , Park Jinseu , Cho Sung‐Woo 
Published: March 2003

An NAD+‐dependent succinic semialdehyde dehydrogenase from bovine brain was inactivated by pyridoxal‐5′‐ phosphate. Spectral evidence is presented to indicate that the inactivation proceeds through formation of a Schiff's base with amino groups of the enzyme. After NaBH4reduction of the pyridoxal‐5′‐phosphate inactivated enzyme, it was observed that 3.8 mol phosphopyridoxyl residues were incorporated/enzyme tetramer. The coenzyme, NAD+, protected the enzyme against inactivation by pyridoxal‐5′‐phosphate. The absorption spectrum of the reduced and dialyzed pyridoxal‐5′‐phosphate‐inactivated enzyme showed a characteristic peak at 325 nm, which was absent in the spectrum of the native enzyme. The fluorescence spectrum of the pyridoxyl enzyme differs completely from that of the native enzyme. After tryptic digestion of the enzyme modified with pyridoxal‐5′‐phosphate followed by [3H]NaBH4reduction, a radioactive peptide absorbing at 210 nm was isolated by reverse‐phase HPLC. The sequences of the peptide containing the phosphopyridoxyllysine were clearly identical to sequences of other mammalian succinic semialdehyde dehydrogenase brain species including human. It is suggested that the catalytic function of succinic semialdehyde dehydrogenase is modulated by binding of pyridoxal‐5′‐phosphate to specific Lys347residue at or near the coenzyme‐binding site of the protein.