共查询到20条相似文献,搜索用时 15 毫秒
1.
F. M. Cazorla M. A. Vázquez J. Rosales E. Arrebola J. Navarro A. Pérez-García A. de Vicente 《Journal of Phytopathology》2005,153(3):181-184
Bacterial leaf spot symptoms of coriander were first observed in January 2003 in three coriander fields in the valley region of the Axarquía (Málaga, Spain), showing a very high incidence. Pseudomonas syringae pv. coriandricola was consistently isolated from diseased plants, identified and its pathogenicity on coriander could be proved. The effective inoculum dose (ED50) of the isolated strains was estimated and it was very similar to those displayed by the P. syringae pv. coriandricola reference strains used as control. This is the first report of bacterial leaf spot on coriander in Spain. 相似文献
2.
Almost all about citrulline in mammals 总被引:2,自引:0,他引:2
Curis E Nicolis I Moinard C Osowska S Zerrouk N Bénazeth S Cynober L 《Amino acids》2005,29(3):177-205
Summary. Citrulline (Cit, C6H13N3O3), which is a ubiquitous amino acid in mammals, is strongly related to arginine. Citrulline metabolism in mammals is divided
into two fields: free citrulline and citrullinated proteins. Free citrulline metabolism involves three key enzymes: NO synthase
(NOS) and ornithine carbamoyltransferase (OCT) which produce citrulline, and argininosuccinate synthetase (ASS) that converts
it into argininosuccinate. The tissue distribution of these enzymes distinguishes three “orthogonal” metabolic pathways for
citrulline. Firstly, in the liver, citrulline is locally synthesized by OCT and metabolized by ASS for urea production. Secondly,
in most of the tissues producing NO, citrulline is recycled into arginine via ASS to increase arginine availability for NO
production. Thirdly, citrulline is synthesized in the gut from glutamine (with OCT), released into the blood and converted
back into arginine in the kidneys (by ASS); in this pathway, circulating citrulline is in fact a masked form of arginine to
avoid liver captation. Each of these pathways has related pathologies and, even more interestingly, citrulline could potentially
be used to monitor or treat some of these pathologies. Citrulline has long been administered in the treatment of inherited
urea cycle disorders, and recent studies suggest that citrulline may be used to control the production of NO. Recently, citrulline
was demonstrated as a potentially useful marker of short bowel function in a wide range of pathologies. One of the most promising
research directions deals with the administration of citrulline as a more efficient alternative to arginine, especially against
underlying splanchnic sequestration of amino acids. Protein citrullination results from post-translational modification of
arginine; that occurs mainly in keratinization-related proteins and myelins, and insufficiencies in this citrullination occur
in some auto-immune diseases such as rheumatoid arthritis, psoriasis or multiple sclerosis. 相似文献
3.
Maria del Mar Trigo Baltasar Cabezudo Marta Recio Francisco Javier Toro 《Aerobiologia》1996,12(2):85-90
In the Mediterranean area, Urticaceae pollen, together with the pollen of olive and grasses, are the aeroallergens with the
highest incidence in the population. From October 1991 to September 1993, with the aid of a Burkard spore-trap, we carried
out a study on the Urticaceae pollen content in the atmosphere of Málaga, a seaside resort situated in the Costa del Sol (southern
Spain). In Málaga, the Urticaceae pollen season is very long and their pollen grains are detected throughout the year. However,
peaks were recorded in March and April and the variables most influencing concentration were maximum air temperature, sunshine
hours and relative humidity. Diurnal patterns show that peaks occur generally from 10:00 h to 16:00 h when the temperature
reaches its highest values. 相似文献
4.
Polyamines and abiotic stress: recent advances 总被引:8,自引:0,他引:8
Summary. In this review we will concentrate in the results published the last years regarding the involvement of polyamines in the
plant responses to abiotic stresses, most remarkably on salt and drought stress. We will also turn to other types of abiotic
stresses, less studied in relation to polyamine metabolism, such as mineral deficiencies, chilling, wounding, heavy metals,
UV, ozone and paraquat, where polyamine metabolism is also modified.
There is a great amount of data demonstrating that under many types of abiotic stresses, an accumulation of the three main
polyamines putrescine, spermidine and spermine does occur. However, there are still many doubts concerning the role that polyamines
play in stress tolerance. Several environmental challenges (osmotic stress, salinity, ozone, UV) are shown to induce ADC activity
more than ODC. The rise in Put is mainly attributed to the increase in ADC activity as a consequence of the activation of
ADC genes and their mRNA levels. On the other hand, free radicals are now accepted as important mediators of tissue injury
and cell death. The polycationic nature of polyamines, positively charged at physiological pH, has attracted the attention
of researchers and has led to the hypothesis that polyamines could affect physiological systems by binding to anionic sites,
such as those associated with nucleic acids and membrane phospholipids. These amines, involved with the control of numerous
cellular functions, including free radical scavenger and antioxidant activity, have been found to confer protection from abiotic
stresses but their mode of action is not fully understood yet. In this review, we will also summarize information about the
involvement of polyamines as antioxidants against the potential abiotic stress-derived oxidative damage.
Authors’ address: Dr. María Patricia Benavides, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956,
Buenos Aires 1113, Argentina 相似文献
5.
Summary. The modeling of whole organism sulfur amino acid flux control has been aided in recent years by advancements in proteomics
and mass spectroscopy-based metabolite analysis. The convergence of these two fields and their respective techniques, as demonstrated
by a new study using yeast by Lafaye et al., has shown that researchers seeking to model whole cell/organism metabolism should
give careful consideration to the relationships connecting enzyme concentration, enzyme activity, substrate concentration,
and metabolic flux. In this paper, we outline some of the fundamental concepts for modeling sulfur amino acid metabolism and
how they relate to our current understanding of mammalian sulfur amino acid metabolism. 相似文献
6.
Summary. The kinetic aspects of the Perinaphthenone-sensitized photooxidation (singlet molecular oxygen [O2 (1Δg)]-mediated) of α-chymotrypsin (α-Chymo) have been studied at pH 8 and pH 11 as well in reverse micelles (RMs) of sodium 1,
4 bis (2-ethylhexyl) sulfosuccinate (AOT) in n-heptane.
The rate constant values for both overall (kt) and chemical (kr) quenching of O2 (1Δg) by α-Chymo in homogeneous media were higher at pH = 11 than at pH = 8, indicating that the OH-ionized tyrosine (Tyr) residues,
clearly dominate the quenching process. Besides, the rate constants in water were higher than those determined in RMs, demonstrating
that the organized medium protects the protein against photooxidation, probably due to a diminution in both, the accessibility
towards oxidizable amino acid residues and the polarity inside the aggregate, as compared to water. The protection effect
of α-Chymo against the attack by the oxidative species O2 (1Δg) in RMs of AOT seems to be due to the increase of protein stability by the encapsulation within the micellar structure.
The effect of both, surfactant concentration and variation of the ratio ([H2O]/[AOT]) = W on the reactive rate constant was also investigated. The process does not depend significantly on micelles concentration
while the kr values increase as W increases. Furthermore, at W = 30, the highest W studied, kr tends to the value obtained in aqueous medium.
Authors’ address: M. A. Biasutti, Departamento de Química, Campus Universitario, Universidad Nacional de Río Cuarto, (X5804ALH)
Río Cuarto, Argentina 相似文献
7.
González-Hernández JC Aguilera-Aguirre L Pérez-Vázquez V Ramírez J Clemente-Guerrero M Cortés-Rojo C Saavedra-Molina A 《Amino acids》2003,24(1-2):163-169
Summary. We studied the role of the D-amino acids (D-aa) D-serine, D-alanine, D-methionine, D-aspartate, D-tyrosine and D-arginine
on rat liver mitochondria. The stability of D-amino acids, mitochondrial swelling, transmembrane potential and oxygen consumption
were studied under oxidative stress conditions in rat liver mitochondria. In the presence of glutamate-malate all D-aas salts
increased mitochondrial swelling, while in the presence of succinate plus rotenone only D-ala, D-arg and D-ser, induced mitochondrial
swelling. The transmembrane potential (ΔΨ) was decreased in the presence of 1 μM Ca2+. The D-aas inhibited oxygen consumption in state 3. The D-aa studied exerted effects on mitochondria via an increase of free
radicals production.
Received January 15, 2002 Accepted April 14, 2002 Published online September 4, 2002
Acknowledgements The authors appreciated the partial economical support from Mexican grants of CONACYT (to A.S.-M. during its sabbatical)
and CIC-UMSNH (2.5) and critical readings from Rafael álvarez-González.
Authors' address: Alfredo Saavedra-Molina, Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo,
Edificio B-3. C.U., Morelia, Mich. 58030. México, Fax: 52-443-326-5788, E-mail: saavedra@zeus.umich.mx 相似文献
8.
Saavedra-Molina A Ramírez-Emiliano J Clemente-Guerrero M Pérez-Vázquez V Aguilera-Aguirre L González-Hernández JC 《Amino acids》2003,24(1-2):95-102
Summary. Nitric oxide is a small potentially toxic molecule and a diatomic free radical. We report the interaction of L-arginine,
oxygen and calcium with the synthesis of nitric oxide in heart mitochondria. Nitric oxide synthesis is increased in broken
rat heart mitochondria compared with intact and permeabilized mitochondria. Intact mitochondria subjected to hypoxia-reoxygenation
conditions accumulated nitric oxide that inhibits oxygen consumption and ATP synthesis. ATPase activity is not affected during
this augment of nitric oxide. Physiological free calcium concentrations protected mitochondria from the damage caused by the
accumulation of nitric oxide. Higher concentrations of the divalent cation increase the damage exerted by nitric oxide.
Received April 15, 2002 Accepted June 17, 2002 Published online November 14, 2002
Acknowledgements This work was supported in part by Mexican Grants from CONACYT (to A.S.M. during its sabbatical) and CIC-UMSNH (2.5).
Authors' address: Alfredo Saavedra-Molina, Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo,
Edificio B-3. C.U., Morelia, Mich. 58030, México, Fax: 52-443-326-5788, E-mail: saavedra@zeus.umich.mx 相似文献
9.
Pontoni G Rotondo F Spagnuolo G Aurino MT Cartenì-Farina M Zappia V Lama G 《Amino acids》2000,19(2):469-476
Summary. Proton Nuclear Magnetic Resonance (NMR) Spectroscopy of urine (as well as of other biological fluids) is a very powerful
technique enabling multi-component analysis useful in both diagnosis and follow-up of a wide range of inherited metabolic
diseases. Among these pathologies, cystinuria is characterised by accumulation in urine of four dibasic amino acids, namely
lysine, arginine, ornithine and cystine; the last one, being only slightly water soluble, generates urolithiasis. The mentioned
aminoacids can be detected in the urine NMR spectrum of cystinuric patients, the most abundant being the lysine (5 mM and
over are often detected), whose typical signals become very high; arginine and ornithine are also usually detectable, although
pathologic concentrations are lower (usually below 2 mM).
The proposed NMR technique is also suitable in monitoring the therapy with α-mercaptopropionylglycine (MPG), providing quantitation
of several metabolites of interest in the follow-up of the pathology, like cystine, creatinine and citrate.
Received May 9, 1999; Accepted September 26, 1999 相似文献
10.
Bio-available amino acids and mineral nitrogen forms in soil of moderately mown and abandoned mountain meadows 总被引:1,自引:0,他引:1
Summary. The abandonment of traditional mowing methods of mountain meadows in the Czech Republic at the end of the last century has
resulted in secondary re-colonization of these areas. Altered accumulation of plant biomass resulted in a deceleration of
N turnover. A mountain meadow may be regarded as a N-limited ecosystem in which plant nutrition is dependent on direct uptake
of soil amino acids. The composition and distribution of ammonium ions, nitrate ions and the 16 bio-available proteinaceuous
amino acids were investigated in the top 7 cm of the Ah horizon of a Gleyic Luvisol in a long-term moderately mown meadow
and an eleven year old, abandoned or uncut meadow. Ammonium N has a dominant role in both ecosystems. The moderately mown
meadow showed accelerated N-turnover and higher net ammonization. The plant community showed a dependence on this form. Plant
utilization of nitrates and amino acids appeared to be negligible. The uncut or abandoned meadow showed net ammonization from
May (start of the experiment) through August, after which plant N-uptake consisted only of amino acids due to microbial immobilization.
The release of bio-available nitrogen from spring until the beginning of summer in the Ah horizon was too low to explain total
plant N-uptake. Glutamic acid, arginine and aspartic acids had the highest concentrations of any of the amino acids analyzed.
Authors’ address: Pavel Formánek, Department of Geology and Pedology, Mendel University of Agriculture and Forestry, Zemedelska
3, 613 00 Brno, Czech Republic 相似文献
11.
A high frequency of satellite association phenomena in a number of specimens of Rattus rattus and R. norvegicus, captured on the coastal fringe of Málaga province (Southern Spain), was found. Only Ag-NOR bearing chromosomes participated in associations in both species. R. rattus is characterized by 14/18 heterologous and R. norvegicus by 5/5 and 13/13 homologous association types. 相似文献
12.
Summary. The influence of the operation conditions (temperature and residence time) of a thermic treatment on the total amount (free
and protein-bound) of amino acid enantiomers of dry fullfat soya was investigated. Total amino acid content was determined
using conventional ion-exchange amino acid analysis of total hydrolysates and chiral amino acid analysis was performed by
HPLC after precolumn derivatization with o-phthaldialdehyde and 1-thio-β-D-glucose tetraacetate. Contrary to corn that was investigated previously, notable racemization
was detected even at lower temperatures. At 140 °C the ratio of the D-enantiomer was 0.87% for glutamic acid, 2.81% for serine,
and 1.92% for phenylalanine; at 220 °C the ratios of the D-enantiomer of the above amino acids were 1.43, 4.61, and 4.68%,
respectively. The concentration of several L-amino acids decreased. At 220 °C there was 10% less L-glutamic acid, 17% less
L-serine, 5% less L-phenylalanine, 6.6% less L-aspartic, acid and 21% less L-lysine than in the control; their loss can be
assigned to different degrees of L – D conversion. While nearly complete transformation of L-phenylalanine can be attributed
to racemization, the main cause of the loss of L-lysine is not racemization. The treatments in the same order of magnitude
resulted in the formation of more D-amino acids and greater extent of racemization of amino acids in fullfat soya than that
of maize.
Authors’ address: J. Csapó, Faculty of Animal Science, Institute of Chemistry, University of Kaposvár, Guba S. u. 40., H-7400
Kaposvár, Hungary 相似文献
13.
Gastón Guzmán 《Economic botany》2008,62(3):404-412
Hallucinogenic Mushrooms in Mexico: An Overview.
Psilocybe, with 53 known hallucinogenic species in Mexico, is the most important and diverse group of sacred mushrooms used by Mexican
indigenous cultures. Psilocybe caerulescens, known by the present-day Nahuatl Indians as teotlaquilnanácatl, is hypothesized to be the ceremonially-used teonanácatl mushroom cited by Sahagún in the 16th century, the true identity of which has remained obscure for centuries. Correcting
a widely disseminated error derived from early published information on Mexican hallucinogenic mushrooms, emphasis is placed
on the fact that Panaeolus species have never been used traditionally in Mexico. Reports of the use of species of Amanita, Clavaria, Conocybe, Cordyceps, Dictyophora, Elaphomyces, Gomphus, Lycoperdon, Psathyrella, and Stropharia as sacred or narcotic mushrooms are discussed. A brief history of the discovery of hallucinogenic mushrooms in Mexico is
presented, as well as notes on their taxonomy, distribution, and traditional use in Mexico.
Hongos Alucinógenos en México: Historia, Taxonomia, Distribución Geográfica y Uso Tradicional. Psilocybe, con 53 especies alucinógenas conocidas en México, es el grupo más importante y más diverso de hongos sagrados usados por las culturas indígenas mexicanas. Se propone aquí que Psilocybe caerulescens, nombrado por los nahuatls de hoy día teotlaquilnanácatl, es el hongo ceremonial teonanácatl citado por Sahagún en el siglo XVI, cuya identidad verdadera permanece oscura desde hace siglos. A fin de corregir un error muy diseminado derivado de los primeros datos publicados sobre los hongos alucinógenos mexicanos, se hará hincapié en el hecho de que las especies Paneolus nunca han sido usadas tradicionalmente en México. Se discutirán aquí informes sobre el uso de especies de Amanita, Clavaria, Conocybe, Cordyceps, Dictyophora, Elaphomyces, Gomphus, Lycoperdon, Psathyrella y Stropharia como hongos sagrados o narcóticos, y se presentará también una breve historia del descubrimiento de hongos alucinógenos en México, como también algunos datos sobre su taxonomía, su distribución, y su uso tradicional en México.相似文献
14.
According to chloroplast rps4 sequence data the genus Syntrichia forms a monophyletic clade clearly separated from Tortula, while Pottia is shown to be polyphyletic and the Rhynchostegiae species (with rostrate lid) are very similar to Tortula. Crossidium is probably polyphyletic. The close affinity of Desmatodon, Stegonia, Pterygoneurum and some of the species of Phascum with Tortula is confirmed by the molecular data.
Received May 23, 2002; accepted August 23, 2002 Published online: November 22, 2002
Address of the authors: O. Werner, R. M. Ros, M. J. Cano, J. Guerra (E-mail: werner@um.es) Departamento de Biología Vegetal
(Botánica), Facultad de Biología, Universidad de Murcia, Campus de Espinardo, E-30100-Murcia, Spain. 相似文献
15.
In an effort to detect factors which may be under positive selection, a survey for such genes in two pathogenic strains of
Helicobacter pylori (J99 and 26695) was performed. Based on an analysis of synonymous and nonsynonymous substitutions, we identified 19 candidate
genes under positive selection. A search for homologues with known crystallographic structures revealed Escherichia coli carbomoyl phosphate synthetase as a homologue of H. pylori carbamoyl phosphate synthetase. Carbamoyl phosphate synthetase as isolated from E. coli is a heterodimeric enzyme that possesses two different but coupled functionalities and is involved in the first committed
step in the separate biosynthetic pathways for arginine and pyrimidine nucleotides. In this study, we provide evidence indicating
that one of these functionalities appears to be under selective pressure. Reports from previously published site-directed
mutagenesis studies point to a decoupling of amidotransferase and synthetase activities. Implications of these findings for
a metabolic enzyme under positive selection are discussed in terms of the mechanisms of H. pylori pathogenesis.
Received: 11 June 2001 / Accepted: 12 September 2001 相似文献
16.
Mühling J Engel J Halabi M Müller M Fuchs M Krüll M Harbach H Langefeld TW Wolff M Matejec R Welters ID Menges T Hempelmann G 《Amino acids》2006,31(1):11-26
Summary. We have examined the effects of Nω-nitro-L-arginine-methylester-hydrochloride [L-NAME; inhibitor of nitric oxide synthase], S-nitroso-N-acetyl-penicillamine
[SNAP; nitric oxide donor], α-difluoro-methyl-ornithine [DFMO; inhibitor of ornithine decarboxylase] arginine or ornithine
as well as the combination of arginine or ornithine with L-NAME, SNAP or DFMO on intracellular free amino- and α-keto acid
profiles and the immune function markers superoxide anion and hydrogen peroxide generation as well as released myeloperoxidase
activity in neutrophils (PMN). Although the underlying mechanisms still remain unclear, we believe from our results that nitric
oxide as well as polyamine-dependent pathways are involved in the signal transmission of free radical molecule, beneficial
nutritional therapy or maleficient pharmacological stress-induced alterations in PMN nutrient composition. Relevant changes
in intragranulocyte free amino- and α-keto acid homeostasis and metabolism, especially, may be one of the determinants in
PMN nutrition that positively or negatively influences and modulate neutrophil host defence capability and immunocompetence. 相似文献
17.
J. Vander Stappen J. De Laet S. Gama-López S. Van Campenhout G. Volckaert 《Plant Systematics and Evolution》2002,234(1-4):27-51
Phylogenetic relationships in Stylosanthes are inferred by DNA sequence analysis of the ITS region (ITS1–5.8S–ITS2) of the nuclear ribosomal DNA in 119 specimens, representing
36 species of Stylosanthes and 7 species of the outgroup genera Arachis and Chapmannia. In all examined specimens of any particular diploid and (allo)polyploid species, only a single ITS sequence type was observed.
This allowed us to identify a parental genome donor for some of the polyploids. In several diploid and polyploid species,
different specimens contained a different ITS sequence. Some of these sequence types were present in more than one species.
Parsimony analysis yielded several well-supported clades that agree largely with analyses of the chloroplast trnL intron and partially with the current sectional classification. Discordances between the nuclear and cpDNA analyses are
explained by a process of allopolyploidization with inheritance of the cpDNA of one parent and fixation of the ITS sequences
of the other. S. viscosa has been an important genome donor in this process of speciation by allopolyploidy.
Received August 14, 2001; accepted March 4, 2002 Published online: November 14, 2002
Addresses of the authors: Jacqueline Vander Stappen, Steven Van Campenhout and Guido Volckaert (E-mail: guido.volckaert@agr.kuleuven.ac.be),
Katholieke Universiteit Leuven, Laboratory of Gene Technology, Kasteelpark Arenberg 21, B-3001 Leuven, Belgium. Jan De Laet,
American Museum of Natural History, Division of Invertebrate Zoology, Central Park West at 79th Street, New York 10024–5192,
USA. Susana Gama-López, Universidad Nacional Autónoma de México, Unidad de Biología, Tecnología y Protipos (UBIPRO), FES-Iztacala,
Laboratorio de Recursos Naturales, Av. de Los Barrios S/N, Colonia Los Reyes Iztacala, Municipio Tlalnepantla, Estado de México,
C.P. 54090, México. Present address: Apartado Postal 154, Cto. Parque No. 3, C.P. 53102, México. 相似文献
18.
19.
Protein-bound advanced glycation endproducts (AGEs) as bioactive amino acid derivatives in foods 总被引:2,自引:0,他引:2
Henle T 《Amino acids》2005,29(4):313-322
Summary. The Maillard reaction or nonenzymatic browning is of outstanding importance for the formation of flavour and colour of heated
foods. Corresponding reactions, also referred to as “glycation”, are known from biological systems, where the formation of
advanced glycation endproducts (AGEs) shall play an important pathophysiological role in diabetes and uremia. In this review,
pathways leading to the formation of individual protein-bound lysine and arginine derivatives in foods are described and nutritional
consequences resulting from this posttranslational modifications of food proteins are discussed. 相似文献
20.
M. J. Velasco-Jiménez P. Alcázar L. R. Valenzuela D. Gharbi C. Díaz de la Guardia C. Galán 《Plant biosystems》2018,152(4):657-665
In Andalusia (southern Spain), Pinus species are found in mountainous areas and nature reserves, though some species are also grown as ornamentals in cities. Annual airborne pollen trends are regarded as an indicator of variations in climate prompted by overall climate change. Airborne pollen concentration also provides a useful tool for analyzing alterations in the distribution of vegetation in response to environmental factors and to changes in land use. The present study analyzed the Pinus pollen season over 22 years (1993–2014) in 4 Andalusian cities (Córdoba, Granada, Jaén, and Málaga), and examined correlations between airborne pollen concentrations and meteorological parameters (temperature and rainfall). Pinus pollen season lasted from March to June, starting first in Málaga and later in eastern Andalusia. Differences between the pollen curves for each city were attributable to differing proportions of pine species in each province. Temperatures during the months prior to flowering tended to fall, prompting delayed onset of the pollen season in most cities. No significant results were observed for rainfall patterns in most cities. Total pollen concentrations increased at most sites, suggesting that the recorded decline in pine-nut output was not influenced by flowering rates, but to the impact of a local pest. 相似文献