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1.
J Hazard Mater ; 416: 125943, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492870

RESUMO

The Pb(II) adsorption characteristics of chemically activated waste activated sewage sludge (WAS) were compared to raw WAS. Adsorption kinetics and equilibrium isotherm parameters were fit using classic adsorption models. HCl and H2SO4 activation terminated any significant sludge-based adsorption. Raw and ZnCl2 activated WAS displayed Langmuir adsorption capacities of 307 mg/g and 274 mg/g, respectively. Surface characterization revealed that chemical activation with ZnCl2 increased the BET surface area for raw WAS from 0.97 m2/g to 1.78 m2/g, but did not significantly change the surface structure. FTIR analyzes and XPS were used to further investigate the nature of lead binding. The relationships between equilibrium ion concentration and Pb(II) adsorption suggest cationic exchange with hydrogen, calcium, and zinc as a significant mechanism of Pb(II) removal alongside electrostatic attraction. The pHPZC was determined as 2.58 and 2.30 for ZnCl2 activated WAS and raw WAS respectively. HNO3 and Ca(NO3)2 demonstrated sufficient elution properties for WAS recovery. For authentic industrial effluent both raw and ZnCl2 activated WAS displayed Pb(II) removal behavior comparable to simulated Pb(II) solutions. In comparison with modified and unmodified sludges from literature, this study demonstrates the auspicious potential of raw WAS as an effective Pb(II) adsorbent independent of pyrolytic or chemical activation.


Assuntos
Esgotos , Poluentes Químicos da Água , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Chumbo , Poluentes Químicos da Água/análise
2.
Rev Sci Instrum ; 87(5): 051804, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-27250371

RESUMO

X-ray mirrors are needed for beam shaping and monochromatization at advanced research light sources, for instance, free-electron lasers and synchrotron sources. Such mirrors consist of a substrate and a coating. The shape accuracy of the substrate and the layer precision of the coating are the crucial parameters that determine the beam properties required for various applications. In principal, the selection of the layer materials determines the mirror reflectivity. A single layer mirror offers high reflectivity in the range of total external reflection, whereas the reflectivity is reduced considerably above the critical angle. A periodic multilayer can enhance the reflectivity at higher angles due to Bragg reflection. Here, the selection of a suitable combination of layer materials is essential to achieve a high flux at distinct photon energies, which is often required for applications such as microtomography, diffraction, or protein crystallography. This contribution presents the current development of a Ru/C multilayer mirror prepared by magnetron sputtering with a sputtering facility that was designed in-house at the Helmholtz-Zentrum Geesthacht. The deposition conditions were optimized in order to achieve ultra-high precision and high flux in future mirrors. Input for the improved deposition parameters came from investigations by transmission electron microscopy. The X-ray optical properties were investigated by means of X-ray reflectometry using Cu- and Mo-radiation. The change of the multilayer d-spacing over the mirror dimensions and the variation of the Bragg angles were determined. The results demonstrate the ability to precisely control the variation in thickness over the whole mirror length of 500 mm thus achieving picometer-precision in the meter-range.

4.
Aust Vet J ; 92(5): 161-5, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24766046

RESUMO

BACKGROUND: Urinary tract infections caused by Corynebacterium urealyticum are uncommon in veterinary medicine. Encrusted cystitis, encrusted pyelitis and uroliths have been described as complications in humans, but only encrusted cystitis and cystoliths have been reported in dogs so far. Because C. urealyticum is usually resistant to all standard antibacterial drugs, antimicrobial treatment and elimination of this microorganism are challenging. CASE REPORT: An 11-month-old female spayed mixed-breed dog was evaluated because of a C. urealyticum urinary tract infection, mineralisation within both renal pelvises and failure of antimicrobial treatment. Physical examination, haematology and biochemistry were unremarkable. Radiographic and ultrasonographic examinations confirmed bilateral nephrolithiasis. Voided uroliths were composed of 100% carbonate apatite. Urinalysis was indicative of bacterial infection. Aerobic culture of the urine and 16S rRNA sequencing identified significant growth of C. urealyticum and susceptibility testing revealed sensitivity to only vancomycin and linezolid. CONCLUSION: Treatment with the oxazolidinone antibacterial, linezolid, in combination with a urine-acidifying diet resulted in elimination of this multiresistant microorganism and complete resolution of nephrolithiasis.


Assuntos
Infecções por Corynebacterium/veterinária , Corynebacterium/isolamento & purificação , Doenças do Cão/microbiologia , Nefrolitíase/veterinária , Infecções Urinárias/veterinária , Sequência de Aminoácidos , Animais , Antibacterianos/uso terapêutico , Apatitas/análise , Sequência de Bases , Corynebacterium/genética , Infecções por Corynebacterium/complicações , Infecções por Corynebacterium/tratamento farmacológico , Infecções por Corynebacterium/microbiologia , Doenças do Cão/tratamento farmacológico , Doenças do Cão/patologia , Cães , Feminino , Dados de Sequência Molecular , Nefrolitíase/complicações , Nefrolitíase/dietoterapia , RNA Ribossômico 16S/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Infecções Urinárias/complicações , Infecções Urinárias/tratamento farmacológico , Infecções Urinárias/microbiologia
5.
Lett Appl Microbiol ; 54(1): 26-31, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22023239

RESUMO

AIMS: Commercially available selective media for methicillin-resistant Staphylococcus aureus (MRSA) were tested for the detection and isolation of methicillin-resistant Staphylococcus pseudintermedius (MRSP). METHODS AND RESULTS: Five different screening agars [mannitol salt agar with oxacillin and BD BBL™ Chromagar™ MRSA (BD Diagnostics); chromID™ MRSA agar (bioMérieux); Oxacillin resistance screening agar base (ORSAB); and Brilliance MRSA agar (Oxoid)] were analysed for the detection of MRSP. Bacteria that may be isolated together with MRSP and may grow on the screening agars were included in the study to determine possible interference with the growth of MRSP. MRSP grew well on all selective media except on BD BBL™ Chromagar™ MRSA (BD Diagnostics) and chromID™ MRSA agar (bioMérieux), on which a low to moderate growth rate was noted. CONCLUSIONS: ORSAB (Oxoid) and Brilliance MRSA agar (Oxoid) are most suitable for the detection and isolation of MRSP from clinical material. SIGNIFICANCE AND IMPACT OF THE STUDY: The importance of MRSP in veterinary medicine is increasing. Diagnostic systems are needed to detect MRSP carrier as soon as possible. This study provides information about selected MRSA screening agars for the detection of MRSP to the clinical microbiologists.


Assuntos
Meios de Cultura/química , Doenças do Cão/diagnóstico , Resistência a Meticilina , Infecções Estafilocócicas/veterinária , Staphylococcus/isolamento & purificação , Ágar/química , Animais , Portador Sadio , Doenças do Cão/microbiologia , Cães , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Oxacilina/farmacologia , Infecções Estafilocócicas/diagnóstico , Infecções Estafilocócicas/microbiologia , Staphylococcus/efeitos dos fármacos , Staphylococcus/crescimento & desenvolvimento
6.
Educ Health (Abingdon) ; 22(2): 269, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20029750

RESUMO

INTRODUCTION: E-learning is a teaching tool used successfully in many medical subspecialties. Experience with its use in urology, however, is scarce. We present our teaching experience with the INMEDEA simulator to teach urological care to medical students. METHODS: The INMEDEA simulator is an interactive e-learning system built around a virtual hospital which includes a department of urology. It allows students to solve virtual patient cases online. In this study, students were asked to prepare two urological cases prior to discussion of the cases in small groups. This blended teaching approach was evaluated by students through anonymous questionnaires. RESULTS: Of 70 4th year medical students 76% judged this teaching method as good or very good. Eighty-seven percent felt that it offered a good way to understand urological diseases better and 72% felt that learning with this method was fun. Nevertheless, 30 out of 70 free text statements revealed that further improvements of the program, including an easier and more comfortable navigation and a faster supply of information are necessary. CONCLUSIONS: Virtual patient cases offer a practicable solution for teaching based on problem solving in urology with a high acceptance rate by students.


Assuntos
Educação de Graduação em Medicina/métodos , Internet , Urologia/educação , Interface Usuário-Computador , Simulação por Computador , Humanos , Inquéritos e Questionários
8.
Plant Mol Biol ; 43(1): 83-101, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10949376

RESUMO

Families of papain- and legumain-like cysteine proteinases (CPR) were found in Vicia seeds. cDNAs and antibodies were used to follow organ specificity and the developmental course of CPR-specific mRNAs and polypeptides. Four papain-like cysteine proteinases (CPR1, CPR2, proteinase A and CPR4) from vetch seeds (Vicia sativa L.) were analysed. CPR2 and its mRNA were already found in dry embryonic axes. CPR1 was only detected there during early germination. Both CPR1 and CPR2 strongly increased later during germination. In cotyledons, both CPR1 and CPR2 were only observed one to two days later than in the axis. Proteinase A was not found in axes. In cotyledons it could only be detected several days after seeds had germinated. CPR4 mRNA and polypeptide were already present in embryonic axes and cotyledons during seed maturation and decreased in both organs during germination. Purified CPR1, CPR2 and proteinase A exhibited partially different patterns of globulin degradation products in vitro. Although the cDNA-deduced amino acid sequence of the precursor of proteinase A has an N-terminal signal peptide, the enzyme was not found in vacuoles whereas the other papain-like CPRs showed vacuolar localization. Four different legumain-like cysteine proteinases (VsPB2, proteinase B, VnPB1 and VnPB2) of Vicia species were analysed. Proteinase B and VnPB1 mRNAs were detected in cotyledons and seedling organs after seeds had germinated. Proteinase B degraded globulins isolated from mature vetch seeds in vitro. VsPB2 and proteinase B are localized to protein bodies of maturing seeds and seedlings, respectively, of V. sativa. Like VsPB2 from V sativa, also VnPB2 of V. narbonensis corresponds to vacuolar processing enzymes (betaVPE). Based on these results different functions in molecular maturation and mobilization of storage proteins could be attributed to the various members of the CPR families.


Assuntos
Cotilédone/enzimologia , Cisteína Endopeptidases/metabolismo , Fabaceae/enzimologia , Hipocótilo/enzimologia , Proteínas de Plantas , Plantas Medicinais , Sementes/enzimologia , Fracionamento Químico , Cisteína Endopeptidases/genética , Regulação da Expressão Gênica no Desenvolvimento , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Germinação/genética , Globulinas/metabolismo , Isoenzimas/genética , Isoenzimas/metabolismo , Papaína/genética , Papaína/metabolismo , Filogenia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Sementes/crescimento & desenvolvimento , Vacúolos/enzimologia , Vacúolos/ultraestrutura
9.
J Exp Bot ; 51(349): 1423-33, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10944156

RESUMO

Vicilin and legumin, the storage globulins of mature dry vetch (Vicia sativa L.) seeds, are found in protein bodies which are present not only in the cotyledons, but also in the radicle, axis and shoot (together, for reasons of simplicity, here called axis). When at 24 h after the start of imbibition (hai) the radicle breaks through the seed coat a major part of the globulins in the axis has already been degraded, whereas in the cotyledons globulin breakdown cannot yet be detected. Globulin mobilization starts with the degradation of vicilin. At 48 hai when globulin mobilization in the cotyledons just begins, the axis is already nearly depleted of globulins. Mobilization of storage globulin is probably brought about by a complex of different cysteine proteinases (CPRs). The papain-like CPR2 and CPR4, and the legumain-like VsPB2, together with their mRNAs, are already present in axes and cotyledons of dry seeds. This means that they must have been formed during seed maturation. Additional papain-like CPRs are formed later during germination and seedling growth. CPR4 and VsPB2 together with their corresponding mRNAs become undetectable as germination and seedling growth proceed. VsPB2 and VsPB2-mRNA are substituted by the homologous legumain-like proteinase B and its mRNA. The composition of stored and newly formed CPRs undergoes developmental changes which differ between axes and cotyledons. It is concluded that storage globulin mobilization in germinating vetch seeds is started by stored CPRs, whereas the mobilization of the bulk of globulin is predominantly mediated by CPRs which are formed de novo.


Assuntos
Cotilédone/metabolismo , Cisteína Endopeptidases/metabolismo , Germinação , Globulinas/metabolismo , Cotilédone/embriologia , Cotilédone/crescimento & desenvolvimento
10.
Planta ; 208(1): 66-72, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10213002

RESUMO

To analyze the role of phosphoenolpyruvate carboxylase (PEPCase, EC 4.1.1.31) during seed development, two cDNA clones encoding two isoforms of PEPCase were isolated from a seed-specific library of Vicia faba. The two sequences (VfPEPCase1 and VfPEPCase2) have a sequence identity of 82 and 89% on the nucleotide and amino acid levels. The VfPEPCase1 mRNA was found to be predominantly expressed in roots and developing cotyledons whereas the VfPEPCase2 mRNA was more abundant in green and maternal tissues. In the cotyledons, PEPCase mRNAs accumulated from early to mid cotyledon stage and decreased thereafter. The PEPCase activity increased continuously during cotyledon development. The enzyme was strongly activated by glucose-6-phosphate, but not by glucose, fructose or sucrose. Asparagine was weakly activating whereas malate, aspartate and glutamate were inhibitory. The inhibitors became less effective with increasing pH. Aspartate was a much stronger inhibitor of cotyledonary PEPCase than glutamate at both pH 7.0 and 7.5. The sensitivity of PEPCase to malate inhibition decreased from early to mid cotyledon stage at a time when storage proteins are synthesized. This indicates activation on the protein level, possibly by protein phosphorylation. Nitrogen starvation in the presence of hexoses but not sucrose decreased mRNA levels of VfPEPCase1 and enzyme activity, indicating control on the mRNA level by both carbon and nitrogen. It is concluded that in developing cotyledons PEPCase is probably important for the synthesis of organic acids to provide carbon skeletons for amino acid synthesis.


Assuntos
Fabaceae/enzimologia , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Fosfoenolpiruvato Carboxilase/metabolismo , Plantas Medicinais , Sequência de Bases , Primers do DNA , DNA Complementar , Fabaceae/embriologia , Fabaceae/crescimento & desenvolvimento , Nitrogênio/metabolismo , Fosfoenolpiruvato Carboxilase/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Sementes/enzimologia
11.
J Mol Evol ; 47(4): 486-92, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9767693

RESUMO

The development of seeds as a specialized organ for the nutrition, protection, and dispersal of the next generation was an important step in the evolution of land plants. Seed maturation is accompanied by massive synthesis of storage compounds such as proteins, starch, and lipids. To study the processes of seed storage protein evolution we have partially sequenced storage proteins from maturing seeds of representatives from the gymnosperm genera Gnetum, Ephedra, and Welwitschia-morphologically diverse and unusual taxa that are grouped in most formal systems into the common order Gnetales. Based on partial N-terminal amino acid sequences, oligonucleotide primers were derived and used for PCR amplification and cloning of the corresponding cDNAs. We also describe the structure of the nuclear gene for legumin of Welwitschia mirabilis. This first gnetalean nuclear gene structure contains introns in only two of the four conserved positions previously characterized in other spermatophyte legumin genes. The distinct phylogenetic status of the gnetalean taxa is also reflected in a sequence peculiarity of their legumin genes. A comparative analysis of exon/intron sequences leads to the hypothesis that legumin genes from Gnetales belong to a monophyletic evolutionary branch clearly distinct from that of legumin genes of extant Ginkgoales and Coniferales as well as from all angiosperms.


Assuntos
Cycadopsida/classificação , Cycadopsida/genética , Evolução Molecular , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/genética , Sequência de Aminoácidos , Dados de Sequência Molecular , RNA Mensageiro/genética , Técnica de Amplificação ao Acaso de DNA Polimórfico , Sementes , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Leguminas
12.
Biochim Biophys Acta ; 1395(3): 329-44, 1998 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-9512669

RESUMO

The chitinase gene FB7-1 of Nicotiana tabacum cv. samsun line 5 was expressed in the two Saccharomyces cerevisiae strains, INVSC2 and H4, under the control of the GAL1 promoter from S. cerevisiae and a multicopy plasmid vector. Both yeast strains express the plant gene as enzymatic active proteins. In transformants of the strain INVSC2, 94% of the total plant chitinase is contained inside the cells, probably within the vacuole which has been confirmed by subcellular fractionation as well as immunohistochemical experiments. This retention inside the cells is due to the C-terminally located 7 amino acids long vacuolar targeting peptide of the prochitinase. When this sequence was removed, chitinase was transported into the culture medium. Pulse-chase experiments revealed that during translation in transformants of both yeast strains one chitinase polypeptide can be immunoadsorbed with specific antibodies. In the case of INVSC2-transformants, newly formed chitinase is modified in a 60 min chase to slightly increase its molecular mass, whereas in H4-transformants the molecular mass constantly remained 32 kDa. By Western blot analysis two chitinase corresponding polypeptides of 32 and 37 kDa were accumulated in the culture medium of both transformants carrying the chitinase gene without the vacuolar targeting sequence. The larger one was very likely O-glycosylated. Whereas, both polypepitdes were also detected in cell extracts of the H4-transformant, only the smaller one was found in the INVSC2-transformant. The plant chitinase passed through the endoplasmic reticulum on its way to the vacuole. The N-terminal signal peptide responsible for the uptake into the endoplasmic reticulum is cleaved correctly. However, cleavage of the vacuolar targeting peptide located at the C-terminus, to give the mature chitinase is obviously influenced by the genetic background of the host strain. In INVSC2-transformants chitinase accumulates in its mature form whereas both the polypeptides of H4-transformants retain their vacuolar targeting peptide. Our results demonstrate that in the case of plant class I chitinase, the plant sorting signal is recognized in yeast cells but post-translational modifications are influenced by the host strain.


Assuntos
Quitinases/genética , Quitinases/metabolismo , Nicotiana/enzimologia , Plantas Tóxicas , Processamento de Proteína Pós-Traducional , Vacúolos/enzimologia , Sequência de Aminoácidos , Sequência de Bases , Quitinases/biossíntese , Clonagem Molecular/métodos , Escherichia coli , Imuno-Histoquímica , Cinética , Mutagênese Sítio-Dirigida , Oligodesoxirribonucleotídeos , Fragmentos de Peptídeos/química , Regiões Promotoras Genéticas , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/metabolismo , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/ultraestrutura , Nicotiana/genética , Vacúolos/ultraestrutura
13.
Eur J Biochem ; 258(2): 546-58, 1998 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-9874222

RESUMO

An asparaginyl-specific cysteine endopeptidase which was named 'legumain-like proteinase' (LLP) and has an apparent molecular mass of 38.1 kDa was isolated from cotyledons of kidney bean (Phaseolus vulgaris L.) seedlings and partially characterized. It is, to our knowledge, the first known proteinase which in vitro extensively degrades native phaseolin, the major storage globulin of this grain legume. Phaseolin that in vitro had been partially degraded by LLP (Pvitro) and phaseolin that was isolated after partial in vivo breakdown 6 days after the start of seed imbibition (Pvivo) showed similar fragment patterns on SDS/polyacrylamide gels. The fragments had identical cleavage sites in Pvitro and Pvivo as determined by partial amino acid sequencing. In both types of partially degraded phaseolin, these cleavage sites have asparagine in the P1 position. Two of the cleavage sites are located in the beta-barrel domain of the C-terminal module and only one cleavage site was found in the beta-barrel domain of the N-terminal module according to the consensus structural model of phaseolin subunits. These results suggest that very likely LLP could in vivo be responsible for the initiation of phaseolin proteolysis. Two different legumain-specific clones named cp6b and p21b were isolated from a cDNA library of germinated bean cotyledons. Cp6b encodes LLP, while p21b encodes a VPE-like enzyme. Southern-blot analysis revealed a single gene copy for Pv-VPE and, presumably, at least two gene copies for LLP in the kidney bean genome. Northern-blot analysis indicated that mRNAs for both clones appear de novo during seed germination. However, the developmental patterns of the transcript levels corresponding to the two clones differed significantly. The temporal pattern of phaseolin degradation and of LLP polypeptide levels agreed well with the suggestion that LLP plays a key role in the mobilization of phaseolin during and after kidney bean germination.


Assuntos
Cotilédone/enzimologia , Cisteína Endopeptidases/química , Cisteína Endopeptidases/genética , Fabaceae/enzimologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Medicinais , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , Genes de Plantas/genética , Dados de Sequência Molecular , Fragmentos de Peptídeos/química , Filogenia , Proteínas de Plantas/química , Estrutura Secundária de Proteína , RNA Mensageiro/genética , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Especificidade por Substrato
14.
Eur J Biochem ; 248(2): 304-12, 1997 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-9346282

RESUMO

Proteinase A is a papain-like cysteine endopeptidase of vetch (Vicia sativa L.) which was assumed to initiate storage-globulin breakdown just after the onset of seed germination. This enzyme was purified from cotyledons of vetch seedlings. On gelatin-containg SDS gels, active proteinase A migrated with an apparent molecular mass of 21 kDa, whereas after heat denaturation its molecular size on SDS/PAGE was 29 kDa. Although proteinase A is capable of hydrolyzing storage globulins in vitro it could not be localized in the protein-body fraction of cotyledons from germinating seeds. cDNA clones encoding proteinase A precursor have been obtained by PCR. The precursor is composed of an N-terminal signal sequence followed by a propeptide, the region encoding mature proteinase A, and a C-terminal KDEL sequence. Mature proteinase A with a derived molecular mass of 25,244 Da does not have the KDEL sequence. The derived amino acid sequence of the proteinase A precursor is 78.2% identical to sulfhydryl-endopeptidase (SH-EP), a cysteine endopeptidase from germinating Vigna mungo seedlings. Northern blot analysis indicated that proteinase A mRNA appears de novo in cotyledons of 1-day-germinated vetch seeds, where its amount increases up to day 6. No proteinase A mRNA was detected in other vetch organs, not even in the embryo axis, which contains stored globulins. By means of antibodies raised against the purified and against recombinantly produced proteinase A, the 29-kDa bands of mature proteinase A were detected in cotyledon extracts of 6-day-germinated seeds when globulin degradation has already far proceeded. The reported data do not agree with the proposed triggering role of proteinase A in storage-globulin breakdown during germination.


Assuntos
Ácido Aspártico Endopeptidases/fisiologia , Fabaceae/metabolismo , Globulinas/metabolismo , Plantas Medicinais , Sequência de Aminoácidos , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Ácido Aspártico Endopeptidases/isolamento & purificação , Sequência de Bases , Compartimento Celular , Cotilédone/imunologia , Cotilédone/metabolismo , DNA Complementar , Ativação Enzimática , Escherichia coli/genética , Fabaceae/química , Regulação da Expressão Gênica de Plantas , Germinação , Dados de Sequência Molecular , Inibidores de Proteases/farmacologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Sementes/enzimologia , Transcrição Gênica
15.
Phytochemistry ; 45(8): 1549-53, 1997 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9254903

RESUMO

A new method for the purification of wheat cysteine proteinase A which plays a key role in the mobilization of seed storage proteins during germination has been developed. It consists of (NH4)2SO4 fractionation, gel filtration, and both ion-exchange and hydrophobic chromatography. Constancy of the specific activity of chromatographic fractions and their SDS-electrophoretic pattern indicates the homogeneity of the final enzyme preparation. However, electrophoresis in nondenaturing conditions revealed three protein bands of similar intensity, each showing proteolytic activity. The N-terminal sequences of all three electrophoretic components are identical. They are also identical to a segment of the amino acid sequence deduced from one of several cDNA clones derived from closely related, but non-identical mRNAs that accumulate in the aleurone layer of gibberellic acid-treated wheat. It is very likely that the three electrophoretic components found are isoenzymes encoded by cDNA clones described by these authors.


Assuntos
Ácido Aspártico Endopeptidases/química , Isoenzimas/química , Triticum/enzimologia , Sequência de Aminoácidos , Ácido Aspártico Endopeptidases/genética , Eletroforese em Gel de Poliacrilamida , Isoenzimas/genética , Dados de Sequência Molecular , RNA Mensageiro/genética
16.
EMBO J ; 16(15): 4489-96, 1997 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-9303293

RESUMO

A single-chain Fv antibody (scFv) gene, which has previously been used to immunomodulate abscisic acid (ABA) activity in transgenic tobacco to create a 'wilty' phenotype, was put under control of the seed-specific USP promoter from Vicia faba and used to transform tobacco. Transformants were phenotypically similar to wild-type plants apart from their seeds. Anti-ABA scFv embryo development differed markedly from wild-type embryo development. Seeds which accumulated similar levels of a scFv that binds to oxazolone, a hapten absent from plants, developed like wild-type embryos. Anti-ABA scFv embryos developed green cotyledons containing chloroplasts and accumulated photosynthetic pigments but produced less seed storage protein and oil bodies. Anti-ABA scFv seeds germinated precociously if removed from seed capsules during development but were incapable of germination after drying. Total ABA levels were higher than in wild-type seeds but calculated free ABA levels were near-zero until 21 days after pollination. We show for the first time seed-specific immunomodulation and the resulting switch from the seed maturation programme to a germination programme. We conclude that the immunomodulation of hormones can alter the development programme of target organs, allowing the study of the directly blocked endogenous molecules and manipulation of the system concerned.


Assuntos
Ácido Abscísico/metabolismo , Sementes/imunologia , Sementes/metabolismo , Ácido Abscísico/antagonistas & inibidores , Ácido Abscísico/imunologia , Sequência de Aminoácidos , Fabaceae/genética , Genes de Plantas , Fragmentos de Imunoglobulinas/genética , Fenótipo , Plantas Geneticamente Modificadas , Plantas Medicinais , Plantas Tóxicas , Regiões Promotoras Genéticas , Engenharia de Proteínas , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Sementes/genética , Nicotiana/genética , Nicotiana/imunologia , Nicotiana/metabolismo
17.
Hereditas ; 126(3): 219-24, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9350136

RESUMO

The 'Salmon system' consists of isogenic but alloplasmic wheat lines with either sexual or autonomous embryo development. Using two-dimensional gel electrophoresis these lines have been screened for proteins potentially involved in the initiation of parthenogenesis. A temporally altered expression of the polypeptide 'P 115.1' in the sexual and parthenogenetic 'Salmon' lines seems to be related with the autonomous embryo formation. Around anthesis when most of the egg cells begin the parthenogenetic development, the polypeptide 'P 115.1' was present in ovaries of the parthenogenetic lines but not in ovaries of the sexual line. Moreover, this polypeptide is only expressed in the ovaries of amphidiploid parthenogenetic plants containing differentiated embryo sacs. It is absent from ovaries of the analogous polyhaploid plants, which lack any embryo sac structure within their ovules. Furthermore, the polypeptide was neither detectable in meristematic tissue of root tips nor in leaves. N-terminal amino acid sequencing identified 'P 115.1' as an alpha-tubulin. Thus, 'P 115.1' apparently represents an embryo sac-specific isoform of alpha-tubulin involved in the initiation of embryo development.


Assuntos
Triticum/fisiologia , Tubulina (Proteína)/biossíntese , Sequência de Aminoácidos , Arabidopsis/genética , Partenogênese , Alinhamento de Sequência , Triticum/genética , Tubulina (Proteína)/química
18.
Eur J Biochem ; 241(1): 221-8, 1996 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-8898910

RESUMO

The G2 (A2B1a) glycinin subunit from soybean (Glycine max L. Merr.) was purified and renatured to the homohexameric holoprotein. This protein along with purified beta-conglycinin were subjected to limited proteolysis by trypsin. The generated polypeptide fragments were separated via SDS/PAGE and the amino acid sequence of the N-terminals was determined. Four cleavage points were detected in the alpha-chain A2 of glycinin as well as in the alpha'-chain of beta-conglycinin. From the known three-dimensional structure of 7S globulin and the hypothetical model of 7S globulin-like 11S globulin structure, it was possible to draw the conclusion that two distinct types of susceptible sites for proteolytic cleavage are characteristic of the subunits of both globulins. The first includes the sequences linking N- and C-terminal domains of both globulins and the sequence of N-terminal extensions of 70-kDa subunits from the vicilin-like 7S globulins. The second type includes the loop between beta-strands E and F of the N-terminal domain of 11S globulins and of the C-terminal domain of 7S globulins. A statistically significant similarity was found between the N-terminal extension of the alpha'-chain of beta-conglycinin and the interdomain linker regions of soybean glycinin and pea legumin. It is proposed that the three sequence regions which form the first type of susceptible sites are of similar structural function and might have evolved from the N-terminal segment of a putative single-domain ancestor.


Assuntos
Globulinas/metabolismo , Glycine max/química , Proteínas de Soja , Sequência de Aminoácidos , Antígenos de Plantas , Sítios de Ligação , Eletroforese em Gel de Poliacrilamida , Evolução Molecular , Dados de Sequência Molecular , Fragmentos de Peptídeos/química , Proteínas de Plantas/química , Conformação Proteica , Sequências Repetitivas de Ácido Nucleico/genética , Proteínas de Armazenamento de Sementes , Análise de Sequência , Homologia de Sequência de Aminoácidos , Tripsina/metabolismo , Tripsina/farmacologia , Leguminas
19.
Plant Physiol ; 111(2): 533-40, 1996 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8787027

RESUMO

The nicotianamine-deficient mutant chloronerva resembles phenotypically an Fe-deficient plant despite the high accumulation of Fe in the leaves, whereas if suffers from Cu deficiency in the shoot. Two-dimensional electrophoretic separation of proteins from root tips and leaves of wild-type Lycopersicon esculentum Mill. cv Bonner Beste and the mutant grown with and without Fe showed a number of consistent differences. In root tips of the Fe-deficient wild type and the Fe-sufficient as well as the Fe-deficient mutant, the expression of glyceraldehyde-3-phosphate dehydrogenase, formate dehydrogenase, and ascorbate peroxidase was increased. In leaves of the Fe-sufficient and -deficient mutant, Cu-containing chloroplastic and cytosolic superoxide dismutase (Cu-Zn) and plastocyanin (Cu) were nearly absent. This low plastocyanin content could be restored by supplying Cu via the xylem, but the superoxide dismutase levels could not be increased by this treatment. The differences in the protein patterns between wild type and mutant indicate that the apparent Fe deficiency of mutant plants led to an increase in enzymes involved in anaerobic metabolism as well as enzymes involved in stress defense. The biosynthesis of plastocyanin was diminished in mutant leaves, but it was differentially induced by increased Cu content.


Assuntos
Cobre/metabolismo , Ferro/metabolismo , Proteínas de Plantas/metabolismo , Solanum lycopersicum/genética , Solanum lycopersicum/metabolismo , Sequência de Aminoácidos , Ácido Azetidinocarboxílico/análogos & derivados , Ácido Azetidinocarboxílico/metabolismo , Eletroforese em Gel Bidimensional , Enzimas/genética , Enzimas/isolamento & purificação , Enzimas/metabolismo , Dados de Sequência Molecular , Mutação , Proteínas de Plantas/genética , Proteínas de Plantas/isolamento & purificação , Homologia de Sequência de Aminoácidos
20.
Appl Microbiol Biotechnol ; 45(1-2): 102-6, 1996 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8920185

RESUMO

The glucoamylase gene of the yeast Arxula adeninivorans was expressed in Kluyveromyces lactis by using the GAP promoter from Saccharomyces cerevisiae and a multicopy plasmid vector. The transformants secreted 90.1% of the synthesized glucoamylase into the culture medium. The secreted glucoamylase activities are about 20 times higher in comparison to those of Saccharomyces cerevisiae transformants using the same promoter. Secreted glucoamylase possesses identical N-terminal amino acid sequences to those secreted by A. adeninivorans showing that cleavage of the N-terminal signal peptide takes place at the same site. Biochemical characteristics of glucoamylase expressed by K. lactis and A. adeninivorans are very similar.


Assuntos
Genes Fúngicos , Glucana 1,4-alfa-Glucosidase/genética , Kluyveromyces/genética , Leveduras/enzimologia , Leveduras/genética , Sequência de Aminoácidos , Sequência de Bases , Mapeamento Cromossômico , DNA Fúngico/genética , Expressão Gênica , Vetores Genéticos , Dados de Sequência Molecular , Plasmídeos/genética , Regiões Promotoras Genéticas , Sinais Direcionadores de Proteínas/genética , Saccharomyces cerevisiae/genética , Transformação Genética
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