ABSTRACT
In this article we studied, by nuclear magnetic resonance relaxation measurements, the disassembly of a virus particle-the MS2 bacteriophage. MS2 is one of the single-stranded RNA bacteriophages that infect Escherichia coli. At pH 4.5, the phage turns to a metastable state, as is indicated by an increase in the observed nuclear magnetic resonance signal intensity upon decreasing the pH from 7.0 to 4.5. Steady-state fluorescence and circular dichroism spectra at pH 4.5 show that the difference in conformation and secondary structure is not pronounced if compared with the phage at pH 7.0. At pH 4.5, two-dimensional (15)N-(1)H heteronuclear multiple quantum coherence (HMQC) spectrum shows approximately 40 crosspeaks, corresponding to the most mobile residues of MS2 coat protein at pH 4.5. The (15)N linewidth is approximately 30 Hz, which is consistent with an intermediate with a rotational relaxation time of 100 ns. The average spin lattice relaxation time (T(1)) of the mobile residues was measured at different temperatures, clearly distinguishing between the dimer and the equilibrium intermediate. The results show, for the first time, the presence of intermediates in the process of dissociation of the MS2 bacteriophage.
Subject(s)
Crystallography/methods , Escherichia coli/virology , Levivirus/chemistry , Models, Molecular , Nuclear Magnetic Resonance, Biomolecular/methods , Protein Denaturation , Viral Proteins/chemistry , Virion/chemistry , Computer Simulation , Dimerization , Macromolecular Substances , Motion , Protein Binding , Protein Conformation , Protein Folding , Virus AssemblyABSTRACT
This study aimed to compare the radiographic characteristics of patients with pulmonary tuberculosis (TB) and human immunodeficiency virus (HIV) infection with those of HIV-negative patients. In all, 275 TB patients attending the outpatients clinics at the University Hospital/UFPE, were studied from January 1997 to March 1999. Thirty nine (14.2%) of them were HIV(+), with a higher frequency of males in this group (p=0.044). Seventy-five percent of the HIV(+) patients and 19% of the HIV(-) had a negative tuberculin test (PPD) (p < 0.001). The proportion of positive sputum smears in the two groups was similar. The radiological finding most strongly associated with co-infection was absence of cavitation (p < 0.001). It may therefore be concluded that the lack of cavitation in patients with pulmonary TB may be considered a useful indicator of the need to investigate HIV infection. This approach could contribute to increasing the effectiveness of local health services, by offering appropriate treatment to co-infected patients.
Subject(s)
HIV Infections/complications , Tuberculosis, Pulmonary/complications , Tuberculosis, Pulmonary/diagnostic imaging , Adolescent , Adult , Aged , Female , Humans , Male , Middle Aged , RadiographyABSTRACT
We report a large Brazilian kindred with 28 cases of the autosomal dominant multiple synostosis syndrome. The main anomalies were symphalangism and carpal and tarsal synostoses. Other common findings included synostosis involving other bones, absence of phalanges and nails, short metacarpals, pes planovalgus with prominent lateral border, hypoplastic alae of nose, short upper lip, and dermatoglyphic abnormalities. This may be a variant of the WL syndrome.
Subject(s)
Abnormalities, Multiple/genetics , Synostosis/genetics , Abnormalities, Multiple/diagnosis , Adolescent , Adult , Aged , Brazil , Child , Child, Preschool , Female , Humans , Male , Middle Aged , Pedigree , Syndrome , Synostosis/diagnosisABSTRACT
An inbred kindred with 15 cases of the autosomal recessive Ellis-van Creveld syndrome is reported. The ages of the 12 living affected varied between 3 and 82 years. The main characteristics include polydactyly of the hands and feet and several other skeletal anomalies, oral manifestations, and malformations of the heart in 50% of the living affected.
