Asunto(s)
Diterpenos , Ácidos Grasos Insaturados/sangre , Factor de Activación Plaquetaria/antagonistas & inhibidores , Choque/tratamiento farmacológico , Anafilaxia/sangre , Anafilaxia/tratamiento farmacológico , Anafilaxia/etiología , Animales , Aspirina/farmacología , Ácidos Grasos Insaturados/antagonistas & inhibidores , Femenino , Ginkgólidos , Imidazoles/farmacología , Cetotifen/farmacología , Lactonas/farmacología , Masoprocol/farmacología , Ratones , Naftalenos/farmacología , Factor de Activación Plaquetaria/farmacología , Ratas , Ratas Endogámicas , Choque/sangre , Choque/etiología , Choque Séptico/sangre , Choque Séptico/tratamiento farmacológico , Choque Séptico/etiologíaRESUMEN
The envelope glycoproteins of Newcastle disease virus (NDV), hemagglutinin-neuraminidase (HN) and fusion (F) proteins, play important roles in determining the host immune response and the virulence of that particular virus strain. The complete nucleotide sequence of the HN and F genes of a highly neurovirulent strain of NDV (Texas G. B., 1948) was determined in an effort to study the molecular basis of this strain's neurotropic properties. Comparison of the predicted amino acid sequences for the HN and F among the American NDV strains revealed that the Texas G. B. and Beaudette C envelope genes are closely related to each other and are less closely related to the avirulent B1 Hitchner strain. We have found 11 amino acid changes in the predicted HN protein between the Beaudette C and Texas G. B. strain but only 2 conservative amino acid changes (amino acids 11 and 197) in the F protein between these two strains. Although the virulence of NDV strains has been related to sequences at the cleavage site of F0, the property of neurovirulence cannot depend solely upon these sequences because there are no sequence differences between the Beaudette C and Texas G. B. strains. We suggest that the neurovirulence phenotype could be due to the molecular properties of the HN protein; however, we cannot exclude the possibility that the two conservative amino acid differences between the two F proteins could also play a role in determining the phenotypic differences between these two virus strains.
Asunto(s)
Genes Virales , Virus de la Enfermedad de Newcastle/genética , Proteínas del Envoltorio Viral/genética , Proteínas Virales de Fusión/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Pollos , ADN/genética , Genes , Proteína HN , Datos de Secuencia Molecular , Virus de la Enfermedad de Newcastle/patogenicidad , Homología de Secuencia de Ácido Nucleico , VirulenciaRESUMEN
The specific attachment of Mycoplasma pneumoniae to the respiratory ciliated epithelium is mediated by a surface protein designated P1. The nucleotide (nt) sequence of the P1 attachment-protein gene has been determined and the amino acid (aa) sequence deduced. mRNA and cDNA sequencing confirm that this gene is transcribed in M. pneumoniae. The predicted amino acid sequence matches the N-terminal 12 aa residues of P1 protein from M. pneumoniae [Jacobs et al., J. Gen. Microbiol. 133 (1987) 2233-2236] beginning with Asn at aa position 60, where aa 1 represents the first codon of the open reading frame (ORF). Notably, the Trp at aa position 69 aligns with a UGA codon deduced from the nucleotide sequence, providing supporting evidence that UGA is read as Trp rather than stop in M. pneumoniae. Analysis of the first 59 aa suggests that it is probably a leader sequence that is processed to yield the mature protein. The codons of the mature P1 protein sequence represent 1568 aa with a calculated Mr of 169,758. A unique feature of this protein sequence is the lack of cysteine, and this was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of M. pneumoniae proteins metabolically labeled with radioactive cysteine or methionine. This study has revealed that the 4881 nt of the P1 structural gene are flanked by ORFs, and there are no obvious ribosome-binding sites or transcription termination sequences in the immediately adjacent regions. This suggests that the P1 gene is transcribed as part of a larger polycistronic message. In addition, a number of untranscribed and therefore nonfunctional P1 epitope sequences were found in the M. pneumoniae genome; their purpose remains unknown.
Asunto(s)
Adhesinas Bacterianas , Proteínas Bacterianas/genética , Genes Bacterianos , Genes , Mycoplasma pneumoniae/genética , Secuencia de Aminoácidos , Secuencia de Bases , Clonación Molecular , Codón , Enzimas de Restricción del ADN , ADN Bacteriano/genética , Vectores Genéticos , Datos de Secuencia MolecularRESUMEN
In a well defined endotoxin (ET) shock model we compared the influence of a selective LOX-inhibitor FLM 5011 and the COX-inhibitor Acetylsalicylic acid (ASA) on survival as well as on their effects on TXB2 and 6-oxo-PGF1 and on selected parameters characterizing the shock syndrome. Pretreatment with both substances reduced the lethality rate. Neither TXB2 nor the PGF1 concentration revealed a consistent trend after therapeutic intervention. None of the investigated mediators could be identified as the primary "shock mediator".
Asunto(s)
Aspirina/uso terapéutico , Inhibidores de la Ciclooxigenasa , Ácidos Láuricos , Inhibidores de la Lipooxigenasa , Oximas , Choque Séptico/tratamiento farmacológico , 6-Cetoprostaglandina F1 alfa/sangre , Animales , Modelos Animales de Enfermedad , Recuento de Leucocitos/efectos de los fármacos , Lipooxigenasa/uso terapéutico , Masculino , Recuento de Plaquetas/efectos de los fármacos , Ratas , Ratas Endogámicas , Choque Séptico/fisiopatología , Tromboxano B2/sangreRESUMEN
Experiments were carried out to lower the mortality (LD70-90) of rats in ovalbumin-induced anaphylactic (DA) shock and in endotoxin-induced (ET) shock, and of mice after injection of Platelet-activating Factor (PAF shock) comparing the effects of the cyclooxygenase (COX)-inhibitors aspirin (ASA), indomethacin, of the COX-/lipoxygenase (LOX)-inhibitors nordihydroguajaretic acid (NDGA), phenidone and X 86 (analogue of BW 755c), of the inhibitor of thromboxane (TX) synthesis HOE 944, of the TX-antagonist BM 13177, of the PAF-antagonist BN 52021 and of ketotifen. Ketotifen was strongly effective in DA shock, COX- and LOX-inhibitors only slightly. Combined COX- and LOX-inhibitors and BN 52021 showed good effects in the ET shock. Ketotifen was inefficacious. All the used substances influenced the PAF shock. The shock syndromes were biochemically characterized by determination of isocitratedehydrogenase (ICDH) activity, lactate, glucose, haematocrit, numbers of thrombocytes and leucocytes, TXB2 and 6-keto-Prostaglandin(PG)F1 alpha.
Asunto(s)
Inhibidores de la Ciclooxigenasa , Inhibidores de la Lipooxigenasa , Choque Séptico/tratamiento farmacológico , Anafilaxia/tratamiento farmacológico , Anafilaxia/mortalidad , Animales , Modelos Animales de Enfermedad , Femenino , Factor de Activación Plaquetaria , Ratas , Ratas Endogámicas , Choque Séptico/mortalidadRESUMEN
From a Mycoplasma pneumoniae genomic library, three recombinant clones encoding approximately one-third of the attachment (P1) gene were identified. P1 fusion proteins expressed by these clones in Escherichia coli were found to be much smaller than expected from the sizes of the cloned DNA fragments. Nucleotide sequence analysis revealed the presence of UGA codons in the open reading frames of two of the clones, explaining the incomplete translation of the inserts. Sequencing data further revealed that two of the recombinant clones did have similar but not identical carboxyl-end sequences. This finding suggests the existence of more than one genomic DNA sequence coding for the 3'-end of the P1 gene. Potential transcriptional regulatory sequences, a possible termination signal at the 3'-end of the P1 gene and possible promoter-like structures, have been recognized.
Asunto(s)
Proteínas Bacterianas/genética , Codón , ADN Bacteriano/genética , Genes Bacterianos , Mycoplasma pneumoniae/genética , ARN Mensajero , Secuencia de Aminoácidos , Secuencia de Bases , ADN Recombinante , Genes , Datos de Secuencia Molecular , Proteínas Recombinantes de Fusión/genética , Regiones Terminadoras GenéticasRESUMEN
In previous studies with hyperimmune rabbit sera and monoclonal antibodies against the P1 protein of Mycoplasma pneumoniae, we obtained evidence of a shared antigenic determinant with a single protein of Mycoplasma genitalium. Because of biologic and morphologic similarities between these two human Mycoplasma species, attempts were made to characterize this cross-reacting protein of M. genitalium (designated MgPa). The protein was surface exposed and had an estimated molecular size of 140 kilodaltons. Electron microscopy with monoclonal antibodies produced against either MgPa or P1 demonstrated that MgPa is located over the surface of the terminal structure of M. genitalium which is covered by a nap layer. These immunologic and morphologic findings suggest that the MgPa protein of M. genitalium could be the counterpart of the P1 protein of M. pneumoniae.