Clinical severity of respiratory adenoviral infection by serotypes in Korean children over 17 consecutive years (1991-2007)
Human adenoviruses (HAdVs) are important causes of acute respiratory tract illness in children.
To evaluate the risk factors for severe respiratory HAdV infections and the temporal change in case-severity in relation to HAdV types.
From January 1991 to December 2007, respiratory HAdV infections of Korean children requiring hospitalization or an emergency room visit were included. An episode of HAdV infection requiring an intensive care unit stay, use of mechanical ventilation and/or death was designated as a severe infection. The medical records were reviewed retrospectively.
A total of 428 respiratory HAdV infections were included in the clinical analysis. The mean age of patients was 2.6 years. The most frequent diagnosis was a lower respiratory tract infection (312/428, 72.9%), and 44% of respiratory HAdV infections occurred in patients with underlying co-morbidities. Fifteen percent of clinical events resulted in severe HAdV infections with a case-fatality rate of 5.1%. HAdV types 7 and 8 were associated with severe infections, after adjusting for co-morbidity and the age of patients (adjusted OR 8.5 and 15.1, respectively, by a logistic regression model). The case-severity of HAdV-7 associated with lower respiratory tract infections has decreased over time, coinciding with the decreasing size of subsequent epidemics after a large outbreak (P for trend = 0.003).
HAdV types 7 and 8 were independent risk factors for severe respiratory HAdV infections. In addition, the overall severity of HAdV-7 associated lower respiratory tract infections has shown a decreasing trend, which may reflect increasing level of herd immunity.
Available from: Bala Rathinasabapathi
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ABSTRACT: A glutaredoxin of the fern Pteris vittata PvGRX5 was previously implicated in arsenic tolerance. Because of possible involvements of glutaredoxins in metabolic adaptations to high temperature stress, transgenic Arabidopsis lines constitutively expressing PvGRX5 were evaluated for thermotolerance. Homozygous lines expressing PvGRX5 exhibited significantly greater tolerance to high temperature stress than the vector control and wild-type, based upon growth during stress and during recovery from stress, and this was related to leaf glutaredoxin specific activities. Measurements of tissue ion leakage, thiobarbituric acid reactive substances and protein carbonyl content showed that PvGRX5-expressors were significantly (P < 0.05) less affected by the high temperature treatment compared to wild-type and vector control lines for damage to membranes and proteins. Immunoblots indicated that specific protein bands, carbonylated during the stress treatment in the control lines, were protected in PvGRX5-expressors, thus implicating PvGRX5 in heat tolerance, likely mediated through cellular protection against oxidative stress.
Available from: Bernd Bukau
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ABSTRACT: The oligomeric AAA+ chaperones ClpB/Hsp104 mediate the reactivation of aggregated proteins, an activity that is crucial for the survival of cells during severe stress. Hsp104 is also essential for the propagation of yeast prions by severing prion fibres. Protein disaggregation depends on the cooperation of ClpB/Hsp104 with a cognate Hsp70 chaperone system. While Hsp70 chaperones are also involved in prion propagation, their precise role is much less well defined compared with its function in aggregate solubilization. Therefore, it remained unclear whether both ClpB/Hsp104 activities are based on common or different mechanisms. Novel data show that ClpB/Hsp104 uses a motor threading activity to remodel both protein aggregates and prion fibrils. Moreover, transfer of both types of substrates to the ClpB/Hsp104 processing pore site requires initial substrate interaction of Hsp70. Together these data emphasize the similarity of thermotolerance and prion propagation pathways and point to a shared mechanistic principle of Hsp70-ClpB/Hsp104-mediated solubilization of amorphous and ordered aggregates.
Available from: László Vígh
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ABSTRACT: It is now recognized that membranes are not simple physical barriers but represent a complex and dynamic environment that affects membrane protein structures and their functions. Recent data emphasize the role of membranes in sensing temperature changes, and it has been shown that the physical state of the plasma membrane influences the expression of a variety of genes such as heat shock genes. It has been widely shown that minor alterations in lipid membranes are critically involved in the conversion of signals from the environment to the transcriptional activation of heat shock genes. Previously, we have proposed that the composition, molecular arrangement, and physical state of lipid membranes and their organization have crucial roles in cellular responses during stress caused by physical and chemical factors as well as in pathological states. Here, we show that transformation of Salmonella enterica serovar Typhimurium LT2 (Salmonella Typhimurium) with a heterologous Delta(12)-desaturase (or with its trans-membrane regions) causes major changes in the pathogen's membrane dynamic. In addition, this pathogen is strongly impaired in the synthesis of major stress proteins (heat shock proteins) under heat shock. These data support the hypothesis that the perception of temperature in Salmonella is strictly controlled by membrane order and by a specific membrane lipid/protein ratio that ultimately causes transcriptional activation of heat shock genes. These results represent a previously unrecognized mode of sensing temperature variation used by this pathogen at the onset of infection.
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