[The role of virological tests in the diagnosis of cytomegalovirus infection in pregnant women]. / A virológiai vizsgálatok szerepe a terhes nok cytomegalovirusfertozésének kiderítésében.

INTRODUCTION: The most harmful and most frequent foetal agent is cytomegalovirus. The progress in diagnostic tools and therapeutic opportunities opened new perspectives in the diagnosis and management of foetal cytomegalovirus infection. AIM: Evaluation of cytomegalovirus virological test results performed during pregnancy between 2007 and 2012. METHOD: Clinical and virology data were retrospectively analysed. RESULTS: 64.5% of the 956 tested women were serologically protected and 33.3% were susceptible to cytomegalovirus. Recent infection was confirmed in 10 pregnant women, while the infection could not be confirmed or excluded in 3 pregnant women. Six pregnant women were asymptomatic, 5 had typical disease, and 2 had abnormal fetal ultrasound. One fetus aborted, congenital infection was confirmed in 2, and was excluded in one of the four newborns tested. CONCLUSIONS: The immunity of women to cytomegalovirus reflects high socioeconomic circumstances. Confimatory tests must be done both in women who have cytomegalovirus disease and those who have IgM positive result detected by enzyme (linked) immunoassay. Screening must be done prior to pregnancy. Strict collaboration between professionals of different medical specialties is necessary.

A predictive model of intein insertion site for use in the engineering of molecular switches.

Inteins are intervening protein domains with self-splicing ability that can be used as molecular switches to control activity of their host protein. Successfully engineering an intein into a host protein requires identifying an insertion site that permits intein insertion and splicing while allowing for proper folding of the mature protein post-splicing. By analyzing sequence and structure based properties of native intein insertion sites we have identified four features that showed significant correlation with the location of the intein insertion sites, and therefore may be useful in predicting insertion sites in other proteins that provide native-like intein function. Three of these properties, the distance to the active site and dimer interface site, the SVM score of the splice site cassette, and the sequence conservation of the site showed statistically significant correlation and strong predictive power, with area under the curve (AUC) values of 0.79, 0.76, and 0.73 respectively, while the distance to secondary structure/loop junction showed significance but with less predictive power (AUC of 0.54). In a case study of 20 insertion sites in the XynB xylanase, two features of native insertion sites showed correlation with the splice sites and demonstrated predictive value in selecting non-native splice sites. Structural modeling of intein insertions at two sites highlighted the role that the insertion site location could play on the ability of the intein to modulate activity of the host protein. These findings can be used to enrich the selection of insertion sites capable of supporting intein splicing and hosting an intein switch.

Engineering a thermoregulated intein-modified xylanase into maize for consolidated lignocellulosic biomass processing.

Plant cellulosic biomass is an abundant, low-cost feedstock for producing biofuels and chemicals. Expressing cell wall-degrading (CWD) enzymes (e.g. xylanases) in plant feedstocks could reduce the amount of enzymes required for feedstock pretreatment and hydrolysis during bioprocessing to release soluble sugars. However, in planta expression of xylanases can reduce biomass yield and plant fertility. To overcome this problem, we engineered a thermostable xylanase (XynB) with a thermostable self-splicing bacterial intein to control the xylanase activity. Intein-modified XynB (iXynB) variants were selected that have <10% wild-type enzymatic activity but recover >60% enzymatic activity upon intein self-splicing at temperatures >59 °C. Greenhouse-grown xynB maize expressing XynB has shriveled seeds and low fertility, but ixynB maize had normal seeds and fertility. Processing dried ixynB maize stover by temperature-regulated xylanase activation and hydrolysis in a cocktail of commercial CWD enzymes produced >90% theoretical glucose and >63% theoretical xylose yields.

MAX1, a regulator of the flavonoid pathway, controls vegetative axillary bud outgrowth in Arabidopsis.

We show that MAX1, a specific repressor of vegetative axillary bud outgrowth in Arabidopsis, acts a positive regulator of the flavonoid pathway, including 11 structural genes and the transcription factor An2. Repression of bud outgrowth requires MAX1-dependent flavonoid gene expression. As the flavonoidless state leads to lateral outgrowth in Arabidopsis, our data suggest that a flavonoid-based mechanism regulates axillary bud outgrowth and that this mechanism is under the control of MAX1. Flavonoid gene expression results in the diminished expression of auxin transporters in the bud and stem, and this, in turn, decreases the rate of polar auxin transport. We speculate that MAX1 could repress axillary bud outgrowth via regulating flavonoid-dependent auxin retention in the bud and underlying stem. Because MAX1 is implicated in synthesis of the carotenoid-derived branch regulator(s) from the root, it likely links long-distance signaling with local control of bud outgrowth.