Effect of mutations found in carbohydrate-deficient glycoprotein syndrome type IA on the activity of phosphomannomutase 2.

Seven mutant forms of human phosphomannomutase 2 were produced in Escherichia coli and purified. These mutants had a Vmax of 0.2-50% of the wild enzyme and were unstable. The least active protein (R141H) bears a very frequent mutation, which has never been found in the homozygous state whereas the second least active protein (D188G) corresponds to a mutation associated with a particularly severe phenotype. We conclude that total lack of phosphomannomutase 2 is incompatible with life. Another conclusion is that the elevated residual phosphomannomutase activity found in fibroblasts of some patients is contributed by their mutated phosphomannomutase 2.

Urbanisation of yellow fever in Santa Cruz, Bolivia.

BACKGROUND: Reinvasion by Aedes aegypti of cities in the Americas poses a threat of urbanisation of yellow fever. After detection of yellow-fever infection in a resident of the city of Santa Cruz, Bolivia, in December, 1997, we investigated all subsequent suspected cases. METHODS: We introduced active surveillance of yellow fever in the Santa Cruz area. Hospitals and selected urban and rural health centres reported all suspected cases. Patients were serologically screened for yellow fever, dengue, hepatitis A and B, and leptospirosis. We collected clinical and epidemiological information from patients' records and through interviews. We also carried out a population-based serosurvey in the neighbourhood of one case. FINDINGS: Between December, 1997, and June, 1998, symptomatic yellow-fever infection was confirmed in six residents of Santa Cruz, five of whom died. Five lived in the southern sector of the city. Two had not left the city during the incubation period, and one had visited only an area in which sylvatic transmission was deemed impossible. Of the 281 people covered in the serosurvey 16 (6%) were positive for IgM antibody to yellow fever. Among five people for whom this result could not be explained by recent vaccination, there were two pairs of neighbours. INTERPRETATION: Urban transmission of yellow fever in Santa Cruz was limited in space and time. Low yellow-fever immunisation coverage and high infestation with A. aegypti in the city, and the existence of endemic areas in the region present a risk for future urban outbreaks. We recommend immediate large-scale immunisation of the urban population, as well as tightened surveillance and appropriate vector control.

PIP: Until recently, urban yellow fever had not been reported from the Americas since 1954, but jungle yellow fever increasingly affects forest dwellers in Bolivia, Brazil, Colombia, Ecuador, and Peru. The reinvasion by Aedes aegypti of cities in the Americas now threatens to urbanize yellow fever. After yellow fever infection was identified in a resident of Santa Cruz, Bolivia, in December 1997, all subsequent suspected cases were investigated. Active surveillance of yellow fever was introduced in the Santa Cruz area, with hospitals and selected urban and rural health centers reporting all suspected cases. Patients were serologically screened for yellow fever, dengue, hepatitis A and B, and leptospirosis; clinical and epidemiological data were collected from patients' records and through interviews; and a population-based serosurvey was conducted in the neighborhood of one case. Between December 1997 and June 1998, symptomatic yellow fever infection was confirmed in 6 residents of Santa Cruz, of whom 5 died. 5 lived in the southern sector of the city. 2 cases did not leave the city during their incubation period, and 1 had visited only an area in which sylvatic transmission was deemed impossible. Of the 281 people covered in the serosurvey, 16 (6%) were positive for IgM antibody to yellow fever. Among 5 people for whom that result could not be explained by recent vaccination, there were 2 pairs of neighbors. This instance of urban yellow fever transmission was limited in both time and space.

Kinetic properties and tissular distribution of mammalian phosphomannomutase isozymes.

Human tissues contain two types of phosphomannomutase, PMM1 and PMM2. Mutations in the PMM2 gene are responsible for the most common form of carbohydrate-deficient glycoprotein syndrome [Matthijs, Schollen, Pardon, Veiga-da-Cunha, Jaeken, Cassiman and Van Schaftingen (1997) Nat. Genet. 19, 88-92]. The protein encoded by this gene has now been produced in Escherichia coli and purified to homogeneity, and its properties have been compared with those of recombinant human PMM1. PMM2 converts mannose 1-phosphate into mannose 6-phosphate about 20 times more rapidly than glucose 1-phosphate to glucose 6-phosphate, whereas PMM1 displays identical Vmax values with both substrates. The Ka values for both mannose 1,6-bisphosphate and glucose 1,6-bisphosphate are significantly lower in the case of PMM2 than in the case of PMM1. Like PMM1, PMM2 forms a phosphoenzyme with the chemical characteristics of an acyl-phosphate. PMM1 and PMM2 hydrolyse different hexose bisphosphates (glucose 1,6-bisphosphate, mannose 1,6-bisphosphate, fructose 1,6-bisphosphate) at maximal rates of approximately 3.5 and 0.3% of their PMM activity, respectively. Fructose 1,6-bisphosphate does not activate PMM2 but causes a time-dependent stimulation of PMM1 due to the progressive formation of mannose 1,6-bisphosphate from fructose 1,6-bisphosphate and mannose 1-phosphate. Experiments with specific antibodies, kinetic studies and Northern blots indicated that PMM2 is the only detectable isozyme in most rat tissues except brain and lung, where PMM1 accounts for about 66 and 13% of the total activities, respectively.

La cobertura de la vacuna de Fiebre Amarilla en Santa Cruz - Bolivia entre 1980 y 1999 / The covering of the vaccine against the Yellow Fever, in Santa Cruz - Bolivia, between 1980 and 1997

La prevencion mas afectiva contra la fiebre amarilla es la vacunacion y la estrategia con mayor costo beneficio para lograr coberturas eficaces es la vacunacion sistematica de la poblacion en riesgo y de futuras generaciones mediante el programa ampliado de Inmunizacion (PAI). Como en otros paises en Africa y America Latina, Bolivia no logro implementar esta estrategia por falta de vacunas. Del otro lado de Bolivia cuenta con una ciudad como Santa Cruz de la Sierra con 1 millon de habitantes en alto riesgo. A fin de estimar la cobertura de vacunacion actual contra la fiebre amarilla en la ciudad de Santa Cruz, se revisaron la literatura cientifica, las estadisticas nacioales y los informes de encuestas realizada a partir del 1980 y se entrevisto a personas claves. La mayoria de las campaña de vacunacion en el Dpto. de Santa Cruz fueron organizadas para contrarrestar brotes de fiebre amarilla selvatica. con la campaña masiva en 1982 en la ciudad de Santa Cruz se llego a una cobertura de 87 por ciento (IC 95 por ciento 81-93) de la poblacion urbana. Los esfuerzos de vacunacion posteriores fueron limitados y no lograron compensar el crecimiento de mas de 200 por ciento de la poblacion. La cobertura bajo a 35 por ciento (IC95 por ciento 31-39) en 1990 y la mejor estimacion de la proteccion inmunitaria para 1997 es de 41 por ciento 41 por ciento (IC 95 por ciento 35-47) para los mayores. Los niños y residentes de zonas perifericas de la ciudad tienen una cobertura menor. La informacion mas confiable proviene de seroencuestas. Los datos obtenido mediante entrevista sobreestiman la cobertura y la falta de datos rutinarios desglosados por ciudad y zona rural junto con el problema de la revacunacion impiden el calculo de la cobertura. Los datos recolectados demuestran que la cobertura actual es insuficiente para proteger la poblacion de la ciudad. Se estima la necesidad de vacunas para una campaña entre 500,000 y 650,000 y se recomienda priorizar los barrios perifericos, los migrantes y todas las personas nacidas despues de 1982 y posteriormente integrar la vacuna contra la fiebre amarilla en el PAI

Short communication: dengue serotype 2 subtype III ('Jamaica') epidemic in Santa Cruz, Bolivia.

BACKGROUND: During the past decade, dengue and dengue haemorrhagic fever (DHF) have become a public health problem in various Latin American countries. Indications of increased dengue cases in the city of Santa Cruz, Bolivia, early in 1997 were promptly investigated. METHODS: We conducted a sample sero-survey in one district of the city. Levels of antidengue IgM were determined and genetic analysis was performed on virus isolates. RESULTS: IgM antibodies were detected in 6.5% (95% CI: 3.4%-9.6%) of adults (over 15 years old) and 5.1% (2.0%-8.2%) of children (5-7 years old). Dengue virus serotype 2 subtype III ('Jamaica') was isolated. CONCLUSIONS: The estimated attack rates are compatible with a dengue epidemic in Santa Cruz. Isolation of dengue-2 'Jamaica' virus documents the further spread of this subtype from the Caribbean via Brazil into South America. Increased DHF preparedness seems mandatory.

A new class of phosphotransferases phosphorylated on an aspartate residue in an amino-terminal DXDX(T/V) motif.

When incubated with their substrates, human phosphomannomutase and L-3-phosphoserine phosphatase are known to form phosphoenzymes with chemical characteristics of an acyl-phosphate. The phosphorylated residue in phosphomannomutase has now been identified by mass spectrometry after reduction of the phosphoenzyme with tritiated borohydride and trypsin digestion. It is the first aspartate in a conserved DVDGT motif. Replacement of either aspartate of this motif by asparagine or glutamate resulted in complete inactivation of the enzyme. The same mutations performed in the DXDST motif of L-3-phosphoserine phosphatase also resulted in complete inactivation of the enzyme, except for the replacement of the second aspartate by glutamate, which reduced the activity by only about 40%. This suggests that the first aspartate of the motif is also the phosphorylated residue in L-3-phosphoserine phosphatase. Data banks contained seven other phosphomutases or phosphatases sharing a similar, totally conserved DXDX(T/V) motif at their amino terminus. One of these (beta-phosphoglucomutase) is shown to form a phosphoenzyme with the characteristics of an acyl-phosphate. In conclusion, phosphomannomutase and L-3-phosphoserine phosphatase belong to a new phosphotransferase family with an amino-terminal DXDX(T/V) motif that serves as an intermediate phosphoryl acceptor.

[Epidemic outbreak of dengue virus 2/Jamaica genotype in Bolivia]. / Brote epidémico de denguevirus 2, genotipo Jamaica, en Bolivia.

OBJECTIVE: To confirm an epidemic outbreak of Dengue virus in the city of Santa Cruz, Bolivia, and to determine the serotype of the virus, to estimate the rate of attack and the proportion of symptomatic infections. MATERIAL AND METHODS: In March 1997, a seroepidemiological survey was conducted with random sampling in a central district of the city of Santa Cruz, Bolivia. Information on recent acute illness and febrile episodes was gathered, and venous blood samples were obtained. Levels of antidengue IgM were determined by MAC Elisa and the virus was typified with RT-PCR. RESULTS: IgM antibodies were detected in 6.5% of adults (CI 95% 3.4-9.6) and 5.1% of children (CI 95% 2.0-8.2). Circulating virus was identified as Dengue serotype 2, subgroup Jamaica. Less than half of the infected children experienced a symptomatic infection compared to almost 90% of adults. CONCLUSIONS: The estimated attack rates are compatible with a Dengue epidemic outbreak in Santa Cruz. The introduction of the serotype 2/ subgroup Jamaica virus into the country increases the risk of hemorrhagic Dengue.

Comparison of PMM1 with the phosphomannomutases expressed in rat liver and in human cells.

Carbohydrate-deficient glycoprotein syndrome type I (CDGI) is most often due to phosphomannomutase deficiency; paradoxically, the human phosphomannomutase gene PMM1 is located on chromosome 22, whereas the CDGI locus is on chromosome 16. We show that phosphomannomutases present in rat or human liver share with homogeneous recombinant PMM1 several kinetic properties and the ability to form an alkali- and NH2OH-sensitive phosphoenzyme with a subunit mass of approximately 30,000 Mr. However, they have a higher affinity for the activator mannose-1,6-bisphosphate than PMM1 and are not recognized by anti-PMM1 antibodies, indicating that they represent a related but different isozyme. Phosphomannomutases belong to a novel mutase family in which the active residue is a phosphoaspartyl or a phosphoglutamyl.

PMM (PMM1), the human homologue of SEC53 or yeast phosphomannomutase, is localized on chromosome 22q13.

We have cloned the human homologue of SEC53 or yeast phosphomannomutase (HGMW-approved symbol PMM1) from a liver cDNA library. This cDNA encodes a protein of 262 amino acids with a predicted molecular mass of 29 kDa and 54% identity with yeast phosphomannomutase. Expression of the human cDNA in Escherichia coli yielded an active phosphomannomutase, which was purified to homogeneity. Northern blot analysis of human tissues showed strong expression in liver, heart, brain, and pancreas and a lower expression in skeletal muscle. The gene was assigned to chromosome 22q13.1 by the use of hybrid cell lines and by fluorescence in situ hybridization. Most patients presenting with carbohydrate-deficient glycoprotein syndrome type 1 (CDG1 or Jaeken disease) have a greatly reduced phosphomannomutase activity; the gene encoding this enzyme is a likely candidate for CDG1. Since the CDG1 locus maps else where in the genome (16p13), mutations in the phosphomannomutase gene encoded by chromosome 22 are not a major cause of CDG1.

La verosimilitud de transmision local de Malaria en areas urbanas y periurbanas de Santa Cruz-Bolivia / The truth about the local transmission of malaria in urban and suburbs of Santa Cruz

La aparicion de casos urbanos de malarias es un problema observado a nivel mundial. La informacion acerca del paludismo en la ciudad de Santa Cruz, Bolivia, es escasa y no permite distinguir entre casos importados y autoctonos. Por los antecedentes de brotes de cuadros febriles sospechosos de malaria, la notificacion esporadicas de casos con resistencia en Santa Cruz y las condiciones favorables para la reproduccion del vector en ciertas zonas periurbanas, se decidio investigar el problema de la malaria urbana mediante entrevista con personas claves y la revision de la informacion en registros de servicios de salud. Por un metodo de mapeo de los casos confirmados durante el año 1994 entre los residentes de Santa Cruz se documento posibles factores de riesgo geograficos y ecologicos. Se delimito de manera cualitativa la areas con un elevado potencial transmision local de malaria por Plasmodium vivax. Se recomienda a corto plazo realizar investigaciones clinicas, epidemiologicas y entomologicas a fin de comprobar o descartar la transmision local. A mediano plazo hay que optimizar el sistema de informacion sanitaria acerca de malaria