Made available in DSpace on 2014-06-11T19:32:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-07-19Bitstream added on 2014-06-13T20:04:03Z : No. of bitstreams: 1 goncalves_mcm_dr_jabo.pdf: 761601 bytes, checksum: 6236742e70d7cbec76cc87afe87574a1 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Foi realizada a clonagem e expressão do gene da glicoproteína HN da estirpe La Sota do vírus da doença de Newcastle (VDN), como proteína recombinante de fusão, contendo uma cauda de poli-histidina no sistema hospedeiro constituído por leveduras da espécie Saccharomyces cerevisiae, que apesar de tentativas de otimização, não evidenciou a expressão da proteína recombinante. Após isso, foram produzidas as porções N-terminal e C-terminal da glicoproteína HN como proteínas recombinantes de fusão contendo uma cauda de poli-histidina e o peptídeo SUMO no sistema hospedeiro constituído pela bactéria Escherichia coli. Contatou-se que o sistema procarioto de expressão foi mais eficiente e permitiu a geração de dois peptídeos, que depois de devidamente caracterizados e purificados foram utilizados como antígenos para a realização de testes de imunodiagnóstico em sustituição aos kits comerciais utilizados atualmente. Foram desenvolvidos dois ensaios de ELISA baseados na adsorção de um antígeno formado pela expressão da porção N-terminal da glicoproteína HN (ELISA HN N-terminal) e na porção C-terminal da mesma glicoproteína (ELISA HN C-terminal), recuperados a partir da purificação da fração solúvel de culturas de E. coli. O ELISA C-terminal mostrou os melhores coeficientes de correlação com o teste padrão HI e com o teste S-ELISA-ConA, além de melhores índices de sensibilidade, especificidade e acurácia. Com isso, o ELISA baseado em um antígeno da porção C-terminal da glicoproteína HN e uma única diluição do soro desenvolvido neste estudo pode ser aplicado no diagnóstico e monitoramento pós-vacinal do VDN / Was carried out the cloning and expression of the glycoprotein gene of the strain La Sota HN of the Newcastle disease virus (NDV), as a recombinant fusion protein containing a poly-histidine tail at the host system consisting of the yeast species Saccharomyces cerevisiae, which despite attempts at optimizing, showed no expression of recombinant protein. After that, the portions N-terminal and C-terminal from glycoprotein HN were produced as recombinant proteins containing a fusion tail and the poly-histidine peptide SUMO at the host system consisting of Escherichia coli. It was noted that the prokaryotic expression system was more efficient and allowed the generation of two peptides, which once characterized and purified were used as antigens for immunodiagnostic tests replacement in the commercial kits currently used. Were developed two ELISA assays based on the adsorption of the antigen formed by expression of the N-terminal portion of the HN glycoprotein (HN ELISA N-terminal) and the C-terminal portion of the same glycoprotein (HN ELISA C-terminus), recovered from purification of the soluble fraction of cultures of E. coli. The C-terminal ELISA showed the best correlation coefficients with the standard HI test and ELISA test S-ConA-, and higher sensitivity, specificity and accuracy. Therefore, the ELISA of the antigen based on a C-terminal portion of the glycoprotein HN and a single serum dilution developed in this study can be applied in the diagnosis and monitoring of post-vaccination VDN

Made available in DSpace on 2014-11-10T11:09:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-01-31Bitstream added on 2014-11-10T11:57:41Z : No. of bitstreams: 1 000792136_20141231.pdf: 436044 bytes, checksum: df19c9ddacbd0b80cd1d62771aece5e9 (MD5) Bitstreams deleted on 2015-01-05T11:00:56Z: 000792136_20141231.pdf,Bitstream added on 2015-01-05T11:01:51Z : No. of bitstreams: 1 000792136.pdf: 1761626 bytes, checksum: 714d3718119b395634a93761902c8401 (MD5) / O vírus da doença de Newcastle (VDN) é o agente causador de uma das mais importantes enfermidades em aves e representa uma ameaça para a indústria avícola. O VDN é membro da família Paramyxoviridae, subfamília Paramyxovirinae, gênero Avulavirus. São vírus envelopados, não-segmentados dotados de genoma RNA de fita simples sentido negativo, associado à doença do trato respiratório, digestivo e nervoso das aves. O controle da DN se baseia em biossegurança, uso de vacinas e detecção precoce de lotes infectados. No presente estudo foi feito o sequenciamento do genoma completo da estirpe vacinal lentogênica (LaSota) e de um isolado de campo brasileiro patogênico (APMV-1/Chicken/Brazil/SJM/75) do VDN, seguido de análise filogenética. Os resultados revelaram que o genoma das estirpes LaSota e APMV-1/Chicken/Brazil/SJM/75 estão constituídos respectivamente por um total de 15.186 e 15.192 nucleotídeos, seis genes na ordem 3'-NP-P-M-F-HN-L-5'. Para a estirpe LaSota o local de clivagem da proteína de fusão (F) apresenta a sequência de aminoácidos correspondentes às encontradas em estirpes não virulentas do VDN, oposto ao que acontece com a estirpe APMV-1/Chicken/Brazil/SJM/75, no qual o sítio de clivagem da proteína F apresenta a sequência de aminoácidos correspondente às encontradas nas estirpes virulentas do VDN. O genoma completo da estirpe LaSota não apresentou grandes diferenças genômicas, de forma que na análise filogenética ficou evidenciado que esta estirpe está classificada no genótipo II, já a estirpe APMV-1/Chicken/Brazil/SJM/75 apresentou grandes diferenças genômicas nas sequências deduzidas de aminoácidos de suas principais proteínas estruturais, de forma que na análise filogenética do genoma completo foi demonstrado que esse vírus está classificado no genótipo V. Os dados obtidos a partir do presente estudo podem contribuir consideravelmente para ... / Newcastle disease virus (NDV) is the agent that causes one of the most important diseases in birds and represents a threat to industrial aviculture. NDV is a member of the Paramyxoviridae family, Paramyxovirinae subfamily, Avulavirus genus. Viruses consist of single-stranded, non-segmented, negative-sense, RNA, associated with diseases in respiratory tract, digestive and nervous in birds. The ND control is based on biosafety, use of vaccines and early detection of infected batches. Here we present the complete genome sequence and phylogenetic analysis of a lentogenic strain (LaSota) and a velogenic strain (APMV-1/Chicken/Brazil/SJM/75) of NDV. The results revealed that the genome of LaSota and APMV-1/Chicken/Brazil/SJM/75 are constituted respectively by a total of 15,186 and 15,192 nucleotides and six genes in the order 3'-NP-P-M-F-HN-L-5’. The cleavage site of fusion protein (F) in LaSota strain shows the amino acid sequence found in non-virulent NDV strains, as opposed to happen with APMV-1/Chicken/Brazil/SJM/75 strain, the cleavage site of the F protein has the amino acid sequence corresponding to that found in virulent strains of NDV. The complete genome of LaSota strain showed no genomic differences and the phylogenetic analysis evidenced that this strain is classified in genotype II. The APMV-1/Chicken/Brazil/SJM/75 strain there are large differences in the genomic sequences and in the deduced amino acid sequences of its major structural proteins, so the phylogenetic analysis of the complete genome was demonstrated that this virus is classified in genotype V. This study can contribute significantly to understand better the genomic evolution of NDV in Brazil and in Americas, such as these strains with genotypic and phenotypic characteristics were no longer isolated in Brazil after 1975, while continued to be isolated in North America

Made available in DSpace on 2014-06-11T19:27:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-28Bitstream added on 2014-06-13T19:56:58Z : No. of bitstreams: 1 silva_kr_me_jabo.pdf: 746958 bytes, checksum: 651e28fc6f5b0bad0768768aa6ff7a22 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A nucleoproteina do vírus da doença de Newcastle (VDN) é um dos componentes antigênicos ideais para fazer o imunodiagnóstico da DN, por ser mais conservada e possuir uma elevada imunogenicidade. A sequência completa do gene da nucleoproteína (NP) (1470 pb) da estirpe La Sota do VDN foi amplificada, nesse estudo, por RT-PCR e submetida a clonagem no vetor de expressão em Escherichia coli pETSUMO (Invitrogen). A proteína NP foi expressa sob a forma de uma proteína recombinante de fusão contendo o peptídeo SUMO e a sequência de poli-histidina, em seguida foi purificada em resina de níquel-agarose e caracterizada por SDSPAGE e Western-blotting, apresentando um peso molecular de cerca de 66kDa e reatividade com anticorpos policlonais de galinhas hiperimunizadas com esse mesmo vírus. Foi então desenvolvido um método indireto de ELISA com essa proteína (NPVDN- ELISA) para ser aplicado na detecção de anticorpos anti-virais específicos. O NP-VDN-ELISA revelou ser capaz de diferenciar amostras de soros positivos para o VDN das amostras de soros negativos e, na comparação dos resultados obtidos na análise de 125 soros de campo pelo NP-VDN-ELISA com os do teste de Inibição da Hemaglutinação (HI), foi encontrado um coeficiente de correlação significante entre estes métodos (r = 0,8345), bem como elevadas sensibilidade (89,3%), acurácia (90,4%) e especificidade (95,5%). Concluindo, a proteína NP recombinante expressa pelo sistema pET SUMO – E. coli compartilha os principais epítopos para interagir com anticorpos de galinhas produzidos contra a proteína NP do VDN, tendo, portanto, um bom potencial de ser aplicada de forma bem sucedida e com vantagens no teste de ELISA para realizar de forma mais rápida e prática, o imunodiagnóstico da DN de um maior número de amostras séricas de galinhas / The nucleocapsid protein (NP) of Newcastle Disease Virus (NDV), is a preferred choice to develop a serologic assay on account of highly conserved sequences, and high immunogenicity. The whole open-reading-frame (orf) of NP gene from LaSota strain of NDV was amplified by RT-PCR and cloned in pETSUMO vector (Invitrogen) and Escherichia coli as cellular host. The NP protein was expressed as a fusion recombinant protein containing SUMO peptide and poly-histidine tags. This protein was easily purified in nickel-agarose resin, and characterized by SDS-PAGE and Western-blotting, showing a molecular weight of approximately 66 kDa and reactivity with polyclonal antibodies from NDV hiperimmunized chickens. The recombinant NP protein was used as antigen to develop an indirect ELISA (NP-NDVELISA) for the detection chicken anti-NDV antibodies. The capability of the recombinant NP protein to differentiate positive from normal chicken sera was evident in NP-NDV-ELISA, and by comparing this ELISA with haemagglutination-inhibition test (HI) a high and significant correlation with the haemagglutination-inhibition test (r = 0,8345), as well as high sensitivity (89,3%), specificity (95,5%) and accuracy (90,4%) were obtained. In conclusion the results indicated that the recombinant NP protein shared the main epitopes with the homologous viral protein and has a great potential to be advantageously used in the ELISA for the analysis of large number of samples in the DN immunodiagnosis

Orientador: Helio José Montassier / Banca: Samir Issa Samara / Banca: Alessandro de Mello Varani / Banca: João Pessoa de Araujo Junior / Banca: Ricardo Luiz Moro de Sousa / Resumo: O vírus da doença de Newcastle (VDN) é o agente causador de uma das mais importantes enfermidades em aves e representa uma ameaça para a indústria avícola. O VDN é membro da família Paramyxoviridae, subfamília Paramyxovirinae, gênero Avulavirus. São vírus envelopados, não-segmentados dotados de genoma RNA de fita simples sentido negativo, associado à doença do trato respiratório, digestivo e nervoso das aves. O controle da DN se baseia em biossegurança, uso de vacinas e detecção precoce de lotes infectados. No presente estudo foi feito o sequenciamento do genoma completo da estirpe vacinal lentogênica (LaSota) e de um isolado de campo brasileiro patogênico (APMV-1/Chicken/Brazil/SJM/75) do VDN, seguido de análise filogenética. Os resultados revelaram que o genoma das estirpes LaSota e APMV-1/Chicken/Brazil/SJM/75 estão constituídos respectivamente por um total de 15.186 e 15.192 nucleotídeos, seis genes na ordem 3'-NP-P-M-F-HN-L-5'. Para a estirpe LaSota o local de clivagem da proteína de fusão (F) apresenta a sequência de aminoácidos correspondentes às encontradas em estirpes não virulentas do VDN, oposto ao que acontece com a estirpe APMV-1/Chicken/Brazil/SJM/75, no qual o sítio de clivagem da proteína F apresenta a sequência de aminoácidos correspondente às encontradas nas estirpes virulentas do VDN. O genoma completo da estirpe LaSota não apresentou grandes diferenças genômicas, de forma que na análise filogenética ficou evidenciado que esta estirpe está classificada no genótipo II, já a estirpe APMV-1/Chicken/Brazil/SJM/75 apresentou grandes diferenças genômicas nas sequências deduzidas de aminoácidos de suas principais proteínas estruturais, de forma que na análise filogenética do genoma completo foi demonstrado que esse vírus está classificado no genótipo V. Os dados obtidos a partir do presente estudo podem contribuir consideravelmente para ... / Abstract: Newcastle disease virus (NDV) is the agent that causes one of the most important diseases in birds and represents a threat to industrial aviculture. NDV is a member of the Paramyxoviridae family, Paramyxovirinae subfamily, Avulavirus genus. Viruses consist of single-stranded, non-segmented, negative-sense, RNA, associated with diseases in respiratory tract, digestive and nervous in birds. The ND control is based on biosafety, use of vaccines and early detection of infected batches. Here we present the complete genome sequence and phylogenetic analysis of a lentogenic strain (LaSota) and a velogenic strain (APMV-1/Chicken/Brazil/SJM/75) of NDV. The results revealed that the genome of LaSota and APMV-1/Chicken/Brazil/SJM/75 are constituted respectively by a total of 15,186 and 15,192 nucleotides and six genes in the order 3'-NP-P-M-F-HN-L-5'. The cleavage site of fusion protein (F) in LaSota strain shows the amino acid sequence found in non-virulent NDV strains, as opposed to happen with APMV-1/Chicken/Brazil/SJM/75 strain, the cleavage site of the F protein has the amino acid sequence corresponding to that found in virulent strains of NDV. The complete genome of LaSota strain showed no genomic differences and the phylogenetic analysis evidenced that this strain is classified in genotype II. The APMV-1/Chicken/Brazil/SJM/75 strain there are large differences in the genomic sequences and in the deduced amino acid sequences of its major structural proteins, so the phylogenetic analysis of the complete genome was demonstrated that this virus is classified in genotype V. This study can contribute significantly to understand better the genomic evolution of NDV in Brazil and in Americas, such as these strains with genotypic and phenotypic characteristics were no longer isolated in Brazil after 1975, while continued to be isolated in North America / Mestre

For many paramyxoviruses, including Newcastle disease virus (NDV), syncytia formation requires the expression of both surface glycoproteins (HN and F) in the same cell, and evidence suggests that fusion involves a specific interaction between the HN and F proteins (23, 73). Because a potential interaction in paramyxovirus infected cells has never been clearly demonstrated, such an interaction was explored in Chapter 2 using coimmunoprecipitation and crosslinking. Both HN and F proteins could be precipitated with heterologous antisera after a five minute radioactive pulse as well as after a two hour chase in non-radioactive media, but at low levels. Chemical crosslinking increased detection of complexes containing HN and F proteins at the cell surface. After crosslinking, intermediate as well as high molecular weight species containing both proteins were precipitated with monospecific antisera. Precipitation of proteins with anti-HN after crosslinking resulted in the detection of complexes which electrophoresed in the stacker region of the gel, from 160-300 kD, at 150 kD and at 74 kD. Precipitates obtained with anti-F after crosslinking contained species which migrated in the stacker region of the gel, between 160-300 kD, at 120 kD and at 66 kD. The 3-4 discrete complexes ranging in size from 160-300 kD contained both HN and F proteins when precipitated with either HN or F antisera. That crosslinking of complexes containing both HN and F proteins was not simply a function of overexpression of viral glycoproteins at the cell surface was addressed by demonstrating crosslinking at early time points post infection, when levels of viral surface glycoproteins are low. Use of cells infected with an avirulent strain of NDV showed that chemically crosslinked HN and F proteins were precipitated independent of cleavage of F0. Furthermore, under conditions that maximized HN protein binding to its receptor, there was no change in the percentages of HN and F0 proteins precipitated with heterologous antisera, but a decrease in F1protein precipitated was observed upon attachment. These data argue that the HN and F proteins interact in the RER. Upon attachment of the HN protein to its receptor, the HN protein undergoes a conformational change which causes a subsequent change in the associated F protein, releasing the hydrophobic fusion peptide into the target membrane and initiating fusion. Chapter 3 explores the stalk region of the NDV HN protein, which has been implicated in both fusion promotion and virus specificity of that activity. The NDV F protein contains two heptad repeat motifs which have been shown by site-directed mutagenesis to be critical for fusion (7, 51, 57). Heptad repeat motifs mediate protein-protein interactions by enabling the formation of coiled-coils. Upon analysis of the stalk region of the NDV HN protein, we identified two heptad repeats. Secondary structure analysis of these repeats suggested the potential for these regions to form alpha-helices. To investigate the importance of this sequence motif for fusion promotion, we mutated the hydrophobic "a" position amino acids of each heptad repeat to alanine or methionine. In addition, hydrophobic amino acids in other positions were also changed to alanine. Every mutant protein retained levels of attachment activity that was greater than or equal to the wild-type protein and bound to conformation-specific monoclonal as well as polyclonal antisera. Neuraminidase activity was variably affected. Every mutation, however, showed a dramatic decrease in fusion promotion activity. The phenotypes of these mutant proteins indicate that individual amino acids within the heptad repeat region of the stalk domain of the HN protein are important for the fusion promotion activity of the protein. These data are consistent with the idea that the HN protein associates with the F protein via specific interactions between the heptad repeat regions of both proteins.

In the modern poultry industry, intense genetic selection for meat production has negatively influenced the reproductive performance of commercial birds. Parthenogenesis, embryonic development in unfertilized eggs without any sperm-egg interactions, is known to hinder the normal fertilization process and could be one of the reasons for this reduced reproductive performance in the poultry industry. Therefore, the overall objective of this research was to gain a better understanding of the process of parthenogenesis using Chinese painted quail as the model. Studies on Chinese painted quail reproduction revealed that they are very inefficient in sustained sperm storage and that number of sperm penetrating the egg and subsequent embryonic development potentially alter egg transit time through the oviduct. This poor sperm storage capacity and high sperm-egg interaction requirement might be responsible for the occurrence of parthenogenesis in this species; and in fact, this makes Chinese painted quail an excellent choice for parthenogenesis research. Further, dams selected for parthenogenesis as well as embryonic development, including parthenogen size, alter egg components by possibly delaying the transit time of the egg through the oviduct. Also, both dams and sires selected for the parthenogenesis trait appear to influence their progenies performance, including 1st wk mortality and occurrence of parthenogenesis. Additionally, vaccination of virgin hens with live pigeon pox virus increases parthenogenesis as well as parthenogen size and livability by the direct action of the virus on the embryo. Moreover, live Newcastle disease virus under in vitro conditions was found to have similar effects on the embryo. Because parthenogenesis exists in the modern poultry industry, even the accidental selection of the trait in either males or females could have a negative impact on overall chick production and performance. Also, as vaccination is a routine practice in the industry, it is possible that vaccination of birds that carry the trait will reduce fertility and hatchability due to enhanced parthenogenesis. Overall, currently it appears that, parthenogenesis is adversely affecting the poultry industry; and therefore, additional research on the accurate determination of losses in the poultry industry due to parthenogenesis could further benefit the industry.

Newcastle disease virus (NDV) is one of the paramyxovirus that has been studied at length since this virus infects the birds of all species. NDV is highly virulent in chickens and results in a high mortality rate because the V protein of NDV is found to inhibit the avian immune response system. No drugs are available for treating NDV therefore, determining the structure of V protein would help in developing a drug that can inactivate the V protein, thereby increasing the host immune response against viral infection. The research here is focused on purification and initial structural analysis of the V protein of NDV. The V protein was purified by gel filtration chromatography and the structure was studied using fluorescence and CD spectroscopy, and NMR. The results suggested that the V protein is unstructured. The research also involved purification and structural analysis of the flowering locus T (FT) protein, which is found to play a major role in theninitiation of flowering in plants. Structural analysis of the FT protein may help in finding the possible domains of the FT protein that interacts with other plant proteins, leading ton flowering. The FT protein was purified by ion exchange chromatography and the structure was studied by fluorescence and CD spectroscopy. The fluorescence data suggested that the FT protein may be folded, where as the CD data was inconclusive. More accurate secondary structure information about the protein could be obtained using NMR, but since the concentration of the FT protein was too low (0.007 mM), proper NMR study was not possible.

Desinfektionsmittel sind ein elementarer Bestandteil der Tierseuchenbekämpfung und damit auch der Lebensmittelsicherheit. Die Prüfung chemischer Desinfektionsmittel ist Voraussetzung für deren zuverlässige Wirksamkeit und zielgerichteten Einsatz. In Deutschland geschieht dies nach den Richtlinien der Deutschen Veterinärmedizinischen Gesellschaft e.V. (DVG). Seit der ersten Fassung sind die Richtlinien einem ständigen Anpassungsprozess unterworfen. Im Zuge der europäischen Harmonisierung gilt es nun, sich gesamteuropäischen Richtlinien, verfasst durch das europäische Komitee für Normung (Comité Européen de Normalisation) (CEN) anzupassen. Das Thema dieser Arbeit entwickelte sich im Kontext der derzeitigen Diskussion über Verbesserungsvorschläge zu den bestehenden Richtlinien und deren Anpassung an die europäischen Normen. Es wurden je zwei Testviren für die Bereiche Tierhaltung und tierärztliche Praxis ausgewählt, um sie auf Eignung für die Viruzidieprüfung zu testen und gegebenenfalls zu etablieren. Des Weiteren wurde in einem zweiten Teil, in Anlehnung an die Forderungen der europäischen Normen die Prüfung zu vereinfachen, ein alternatives Zellkulturnachweissystem für das Newcastle-Disease-Virus (NDV) geprüft. Die Prüfung der viruziden Wirksamkeit erfolgte mit fünf verschiedenen Grundsubstanzen, gewählt um ein möglichst breites Spektrum an Desinfektionsmittelwirkstoffen abzudecken. Es wurden Glutaraldehyd, Ethanol, Natronlauge, Natriumhypochlorit und Peressigsäure verwendet. Die Versuche wurden mit einer niedrigen Eiweißbelastung und bei einer Temperatur von 20°C durchgeführt. Um eine praxisnahe Situation zu simulieren wurde auf, bereits in den DVG-Richtlinien, verankerten Stahl- und Holzkeimträgertests zurückgegriffen. Als mögliche Prüfviren für die Tierhaltung wurden das Equine Arteritis-Virus (EAV) und das Bovine Virus Diarrhoe Virus verwendet. Bei beiden Viren handelt es sich um weit verbreitete Tierseuchenerreger mit einer großen epidemiologischen Bedeutung. Die Untersuchung von fünf verschiedenen Desinfektionsmitteln erfolgte im Keimträgertest auf Holz. Sowohl EAV als auch BVD stellen ein weniger geeignetes Prüfvirus dar, da beide Viren enorme Titerverluste im Trocknungsvorgang der Holzkeimträger zeigten. Die Viren ließen sich zwar leicht vermehren, aber die erzielten Ausgangstiter reichten nicht aus um die Trocknungsverluste zu kompensieren und aussagekräftige Ergebnisse zu produzieren. Für den Bereich tierärztliche Praxis wurden das Feline Coronavirus (FCoV) und das Murine Parvovirus (MPV) genutzt. FCoV ist ein weltweit in Hauskatzenpopulationen vorkommendes Virus mit einer hohen Seroprävalenz und wurde daher ausgewählt. MPV wurde als Stellvertreter für die, in der Praxis häufig vorkommenden Parvovirusinfektionen gewählt. Es schien ein ideales Modellvirus aufgrund seiner weiten Verbreitung in der Forschung zu sein. Bei beiden Viren erfolgte die Prüfung auf Stahlkeimträgern. Unter Laborbedingungen konnte FCoV ohne Probleme zu hohen Titern vermehrt werden. Es gab keine nennenswerten Trocknungsverluste. FCoV erwies sich als geeignetes Prüfvirus. MPV hingegen ist bedingt durch die langen Versuchszeiten und schwierig auszuwertenden Zellkulturen, sowie wegen der niedrigen Ausgangstiter weniger geeignet als Modellvirus für die Desinfektionsmittelprüfung. Die Anzucht von NDV in Allantoisflüssigkeit von SPF Hühnereiern erschien sehr aufwendig und mit hohem Eiweißfehler belastet. In den Versuchen konnte ein deutlich höherer Eiweißgehalt als in den vergleichend geprüften, in Zellkultur angezogenen Viren nachgewiesen werden. Infolge der Probleme mit der Kultivierung der LMH-Zelllinie und den damit verbundenen langen Wartezeiten bis zur eigentlichen Versuchsdurchführung kann nur eine teilweise Empfehlung, von auf Zellkultur vermehrtem NDV (NDV (ZK)) gegeben werden. Nach Behebung dieser Probleme ist durchaus eine Ablösung, von in Allantoisflüssigkeit angezüchtetem NDV durch NDV (ZK) zu empfehlen. Die Verfälschung der Ergebnisse durch die höheren Eiweißgehalte bei Desinfektionsmitteln mit deutlichem Eiweißfehler könnten so vermieden werden.

Orientador: Helio Jose Montassier / Banca: Ricardo Luiz Moro de Sousa / Banca: Manoel Victor Franco Lemos / Banca: Camillo Del Cistia Andrade / Banca: Everlon Cid Rigobelo / Resumo: Foi realizada a clonagem e expressão do gene da glicoproteína HN da estirpe La Sota do vírus da doença de Newcastle (VDN), como proteína recombinante de fusão, contendo uma cauda de poli-histidina no sistema hospedeiro constituído por leveduras da espécie Saccharomyces cerevisiae, que apesar de tentativas de otimização, não evidenciou a expressão da proteína recombinante. Após isso, foram produzidas as porções N-terminal e C-terminal da glicoproteína HN como proteínas recombinantes de fusão contendo uma cauda de poli-histidina e o peptídeo SUMO no sistema hospedeiro constituído pela bactéria Escherichia coli. Contatou-se que o sistema procarioto de expressão foi mais eficiente e permitiu a geração de dois peptídeos, que depois de devidamente caracterizados e purificados foram utilizados como antígenos para a realização de testes de imunodiagnóstico em sustituição aos kits comerciais utilizados atualmente. Foram desenvolvidos dois ensaios de ELISA baseados na adsorção de um antígeno formado pela expressão da porção N-terminal da glicoproteína HN (ELISA HN N-terminal) e na porção C-terminal da mesma glicoproteína (ELISA HN C-terminal), recuperados a partir da purificação da fração solúvel de culturas de E. coli. O ELISA C-terminal mostrou os melhores coeficientes de correlação com o teste padrão HI e com o teste S-ELISA-ConA, além de melhores índices de sensibilidade, especificidade e acurácia. Com isso, o ELISA baseado em um antígeno da porção C-terminal da glicoproteína HN e uma única diluição do soro desenvolvido neste estudo pode ser aplicado no diagnóstico e monitoramento pós-vacinal do VDN / Abstract: Was carried out the cloning and expression of the glycoprotein gene of the strain La Sota HN of the Newcastle disease virus (NDV), as a recombinant fusion protein containing a poly-histidine tail at the host system consisting of the yeast species Saccharomyces cerevisiae, which despite attempts at optimizing, showed no expression of recombinant protein. After that, the portions N-terminal and C-terminal from glycoprotein HN were produced as recombinant proteins containing a fusion tail and the poly-histidine peptide SUMO at the host system consisting of Escherichia coli. It was noted that the prokaryotic expression system was more efficient and allowed the generation of two peptides, which once characterized and purified were used as antigens for immunodiagnostic tests replacement in the commercial kits currently used. Were developed two ELISA assays based on the adsorption of the antigen formed by expression of the N-terminal portion of the HN glycoprotein (HN ELISA N-terminal) and the C-terminal portion of the same glycoprotein (HN ELISA C-terminus), recovered from purification of the soluble fraction of cultures of E. coli. The C-terminal ELISA showed the best correlation coefficients with the standard HI test and ELISA test S-ConA-, and higher sensitivity, specificity and accuracy. Therefore, the ELISA of the antigen based on a C-terminal portion of the glycoprotein HN and a single serum dilution developed in this study can be applied in the diagnosis and monitoring of post-vaccination VDN / Doutor

The fusion protein of the Newcastle Disease Virus (NDV) contains three hydrophobic domains. To explore the topogenic signals of these domains, mutants were constructed in which each of the hydrophobic domains was deleted. The membrane insertion and topology of these proteins was characterized in a wheat germ cell-free translation system supplemented with canine microsomal membranes. The results indicated that the first 13 amino acids of the fusion protein are necessary to confer translation inhibition by SRP. Translocation of the nascent chains containing all or part of the first hydrophobic sequence resulted in the appearance of a species of higher molecular weight consistent with glycosylation of at least four of the five potential N-linked glycosylation sites. When glycosylation was inhibited with a glycosylation competitor peptide, signal sequence cleavage was detected. Protease digestion of mutants missing the C-terminal hydrophobic domain indicated that the C-terminus has stop transfer activity. A comparison of membrane insertion of the wild-type fusion protein to that of a mutant missing the second hydrophobic domain, the fusion sequence, indicated that the fusion domain has stop-transfer activity when synthesized in vitro. Furthermore, the fusion domain shows little signal sequence activity when positioned near the amino terminus of the fusion protein. The fusion protein has a highly conserved leucine zipper motif immediately upstream from the transmembrane domain of the F1 subunit. In order to determine the role that the conserved leucines have for the oligomeric structure and biological activity of the NDV fusion protein, the heptadic leucines at positions 481,488, and 495 were changed individually and in combination to an alanine residue. Whereas single amino acid changes had little effect on fusion, substitution of two or three leucine residues abolished the fusogenic activity of the protein although cell surface expression of the mutants and sedimentation in sucrose gradients was similar to that of the wild type. Furthermore, deletion of the C-terminal 91 amino acids, including the leucine zipper motif and transmembrane domain resulted in secretion of an oligomeric structure. These results indicate that the conserved leucines do not play a role in oligomer formation but are required for the fusogenic ability of the protein. When the polar face of the potential alpha helix was altered by nonconservative substitutions of a serine-to-alanine (position 473), glutamic acid-to-lysine (position 482) or an asparagine-to-lysine (position 485), the fusogenic ability of the protein was not significantly disrupted. A phenylalanine residue is at the amino terminus of the F1 protein of all paramyxovirus fusion proteins with the exception of the avirulent strains which have a leucine residue in this position. To explore the role of this phenylalanine in the fusion activity of the protein, this residue was changed to leucine (F117L) or to glycine (F117G) by site-specific mutagenesis while maintaining the cleavage site sequence of virulent strains of NDV. Whereas both the wild-type and the F117G proteins were proteolytically cleaved and F1 was detected, the leucine subsitution abolished cleavage. When co-expressed with the HN protein, the fusion protein with either a phenylalanine and glycine residue at position 117, but not a leucine, was shown to stimulate membrane fusion. However, incubation in trypsin activated the fusion activity of the F117L protein. Thus the presence of a leucine at position 117 of the precursor sequence blocks cleavage, but not fusion acitivity, and indicated that the phenylalanine at the amino terminus of the F1 subunit is not conserved for the fusion activity of the protein.