L-2-Hydroxyglutaric aciduria presenting with severe autistic features

L-2-Hydroxyglutaric aciduria (L-2-HGA) is an autosomal recessive neurometabolic disorder characterized by psychomotor delay, ataxia, macrocephaly and typical neuroradiological findings of subcortical leucoencephalopathy. Recently, the disease causing gene has been discovered (L2HGDH) encoding L-2-hydroxyglutarate dehydrogenase. We present a 3-year-old boy with L-2-HGA, who demonstrated macrocephaly, noted already in utero with ultrasound. Cranial MRI demonstrated diffuse subcortical encephalopathy with increased signal of the subcortical white matter. Subsequent metabolic screening revealed increased levels of L-2-HGA, and genomic DNA analysis demonstrated two missense mutations in L-2-HGDG. Patient's further motor development was mildly impaired, whilst his speech development was profoundly impaired (first words at the age of 2 years). Since the age of 2 years he started demonstrating autistic repetitive behaviors and movements, increasing aloofness to his environment and limitations in the variety of spontaneous activity (CARS score: 44/60-severe autism). Autism has not so far been described in L-2-HGA and may be considered as an additional feature of the phenotypic spectrum.

Occurrence and hygienic relevance of fungi in drinking water

Fungi, above all filamentous fungi, can occur almost everywhere, even in water. They can grow in such a quantity in water that they can affect the health of the population or have negative effects on food production. There are several reports of fungal growth in water from different countries, but to our knowledge none from Austria so far. The aim of this study was to gain an overview of the spectrum of filamentous fungi and yeasts in drinking water systems. Thirty-eight water samples from drinking water and groundwater were analysed. Fungi were isolated by using membrane filtration and plating method with subsequent cultivation on agar plates. The different taxa of fungi were identified using routine techniques as well as molecular methods. Fungi were isolated in all water samples examined. The mean value for drinking water was 9.1 CFU per 100 ml and for groundwater 5400 CFU per 100 ml. Altogether 32 different taxa of fungi were found. The taxa which occurred most frequently were Cladosporium spp., Basidiomycetes and Penicillium spp. (74.6%, 56.4% and 48.7%, respectively). This study shows that drinking water can be a reservoir for fungi, among them opportunists, which can cause infections in immunosuppressed patients.

Effects of cholesterol and simvastatin treatment in patients with Smith-Lemli-Opitz syndrome (SLOS)

Smith-Lemli-Opitz syndrome (SLOS) is a malformation syndrome caused by deficiency of 7-dehydrocholesterol reductase catalysing the last step of cholesterol biosynthesis. This results in an accumulation of 7- and 8-dehydrocholesterol (7 + 8-DHC) and, in most patients, a deficiency of cholesterol. Current therapy consists of dietary cholesterol supplementation, which raises plasma cholesterol levels, but clinical effects have been reported in only a few patients. Hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors were shown to reduce 7 + 8-DHC levels and increase cholesterol concentrations in two small trials with divergent clinical outcome. This retrolective study evaluates the effects of cholesterol only and of cholesterol plus the HMG-CoA reductase inhibitor simvastatin on plasma sterols in 39 SLOS patients and on anthropometric measures in 20 SLOS patients. Cholesterol as well as additional simvastatin decreased the plasma (7 + 8-DHC)/cholesterol ratio. However, the mechanism leading to the decreasing ratio was different. Whereas it was due to an increasing cholesterol concentration in the cholesterol-only cohort, a decreasing 7 + 8-DHC concentration was demonstrated in the cohort receiving additional simvastatin. We could not confirm a positive effect of simvastatin treatment on anthropometric measures or behaviour, as previously reported.

Ethylmalonic encephalopathy: clinical and biochemical observations

Ethylmalonic encephalopathy (EE) is a rare, recently defined inborn error of metabolism which affects the brain, gastrointestinal system and peripheral blood vessels and is characterized by a unique constellation of clinical and biochemical features. A 7-month-old male, who presented with psychomotor retardation, chronic diarrhea and relapsing petechiae is described with the objective of highlighting the biochemical and neuroradiological features of this disorder as well as the effect of high-dose riboflavin therapy. Urinary organic acid analysis revealed markedly increased excretion of ethylmalonic acid, isobutyrylglycine, 2-methylbutyrylglycine and isovalerylglycine. Acylcarnitine analysis in dried blood spots showed increased butyrylcarnitine. Short-chain acyl-CoA dehydrogenase (SCAD) activity in muscle was normal as were mitochondrial OXPHOS enzyme activities in cultured skin fibroblasts. In skeletal muscle the catalytic activity of complex II was decreased. Brain MRI revealed bilateral and symmetrical atrophy in the fronto-temporal areas, massive enlargement of the subarachnoid spaces and hyperdensities on T (2) sequences of the basal ganglia. Mutation analysis of the ETHE1 gene demonstrated homozygosity for the Arg163Gly mutation, confirming the diagnosis of EE at a molecular level. On repeat MRI, a significant deterioration was seen, correlating well with the clinical deterioration of the patient.

Abnormal sterol metabolism in holoprosencephaly: studies in cultured lymphoblasts

BACKGROUND

Holoprosencephaly (HPE) is the most common structural malformation of the developing forebrain in humans. The aetiology is heterogeneous and remains unexplained in approximately 75% of patients.

OBJECTIVE

To examine cholesterol biosynthesis in lymphoblastoid cell lines of 228 patients with HPE, since perturbations of cholesterol homeostasis are an important model system to study HPE pathogenesis in animals.

METHODS

An in vitro loading test that clearly identifies abnormal increase of C27 sterols in lymphoblast-derived cells was developed using [2-(14)C] acetate as substrate.

RESULTS

22 (9.6%) HPE cell lines had abnormal sterol pattern in the in vitro loading test. In one previously reported patient, Smith-Lemli-Opitz syndrome was diagnosed, whereas others also had clearly reduced cholesterol biosynthesis of uncertain cause. The mean (SD) cholesterol levels were 57% (15.3%) and 82% (4.7%) of total sterols in these cell lines and controls, respectively. The pattern of accumulating sterols was different from known defects of cholesterol biosynthesis. In six patients with abnormal lymphoblast cholesterol metabolism, additional mutations in genes known to be associated with HPE or chromosomal abnormalities were observed.

CONCLUSIONS

Impaired cholesterol biosynthesis may be a contributing factor in the cause of HPE and should be considered in the evaluation of causes of HPE, even if mutations in HPE-associated genes have already been found.

Identification of 14 novel mutations in DHCR7 causing the Smith-Lemli-Opitz syndrome and delineation of the DHCR7 mutational spectra in Spain and Italy

The Smith-Lemli-Opitz syndrome (SLOS) is a phenotypically variable metabolic malformation and mental retardation syndrome for which more than 80 mutations in the DHCR7 disease-causing gene have been described. The DHCR7 mutational spectra differ significantly in different areas of Europe, and several common putative founder mutations account for a substantial fraction of all mutations in some ethnic groups. Here we have analysed 47 SLOS patients and describe 14 newly identified mutations in 18 SLOS patients of Ashkenazi Jewish, Austrian, British, German, Italian, Irish, Polish, Portuguese, and Spanish origins. Half of the new mutations are in the transmembrane domains of the protein. In addition, there were two null mutations, one mutation in the 4th cytoplasmic loop, two mutations in the first and last codons, and three mutations in other regions such as the second cytoplasmic loop and the first endoplasmic loop. The analysis included 20 Spanish and 12 Italian SLOS patients and revealed very different mutation spectra in these patients compared to previously described patients from Czechoslovakia, Germany, Poland, and the UK and implicated p.Thr93Met on the J haplotype as the most frequent Mediterranean founder mutation.

Mutations in the gene encoding peroxisomal sterol carrier protein X (SCPx) cause leukencephalopathy with dystonia and motor neuropathy

In this report, we describe the first known patient with a deficiency of sterol carrier protein X (SCPx), a peroxisomal enzyme with thiolase activity, which is required for the breakdown of branched-chain fatty acids. The patient presented with torticollis and dystonic head tremor as well as slight cerebellar signs with intention tremor, nystagmus, hyposmia, and azoospermia. Magnetic resonance imaging showed leukencephalopathy and involvement of the thalamus and pons. Metabolite analyses of plasma revealed an accumulation of the branched-chain fatty acid pristanic acid, and abnormal bile alcohol glucuronides were excreted in urine. In cultured skin fibroblasts, the thiolytic activity of SCPx was deficient, and no SCPx protein could be detected by western blotting. Mutation analysis revealed a homozygous 1-nucleotide insertion, 545_546insA, leading to a frameshift and premature stop codon (I184fsX7).

Astrocytic factors deactivate antigen presenting cells that invade the central nervous system

We hypothesized that CNS tissue has the potential to deactivate invading monocytes/macrophages in order to maintain the immune privilege of the brain, and furthermore, that astrocytes are the cells that initiate monocyte/macrophage deactivation. To test this hypothesis, fluorescent prelabeled rat spleen macrophages with typical amoeboid morphology were transferred into organotypic hippocampal slice cultures (OHSCs), where they gradually developed a ramified morphology similar to the appearance of resting microglial cells. This morphological transformation also occurred if macrophages or monocytes were co-cultured with mixed glial cultures or with astrocytoma cells, and ramification was accompanied by reduced expression of adhesion molecules leukocyte function antigen (LFA)-1, intercellular adhesion molecule (ICAM)-1, and major histocompatibility complex (MHC)-class-II molecules. Moreover, treatment of macrophages with astrocyte culture supernatant effectively down-regulated the LPS-induced expression of adhesion- and MHC-class-II-molecules. Astrocyte supernatant-induced inhibition of adhesion and MHC-class-II-molecule expression was mimicked by transforming growth factor (TGF)-beta1, furthermore, this inhibitory effect was diminished by simultaneous treatment with neutralizing anti-TGF-beta-antibodies. In conclusion, our results suggest that astrocyte-derived, soluble factors that are present in the CNS microenvironment deactivate invading macrophages, thus contributing to the maintenance of CNS immune-privilege following impairment of blood-brain-barrier (BBB) integrity.

L-2-Hydroxy-Glutarazidurie - eine seltene Differenzialdiagnose der Makrozephalie

We report on a 9-year-old girl who was referred to our department because of increasing macrocephaly and school problems. The neurological examination disclosed mild cerebellar dysfunction and positive pyramidal tract signs. An MRI of the brain revealed extensive signal alterations of the white matter. Biochemical investigations established the diagnosis of L-2-hydroxyglutaric aciduria which has to be kept in mind as a rare cause of macrocephaly.

Lethal brain abscess due to the fungusScedosporium apiospermum(teleomorphPseudallescheria boydii) after a near-drowning incident: case report and review of the literature

A 39-year-old healthy man developed a brain abscess weeks after a near-drowning incident. Scedosporium apiospermum, the anamorph of Pseudallescheria boydii, was isolated from the abscess. The patient died 153 days after the accident despite antifungal therapy. We discuss the role of antifungals and review the literature for comparable cases.

Smith-Lemli-Opitz syndrome with a classical phenotype, oesophageal achalasia and borderline plasma sterol concentrations

The diagnostic biochemical hallmarks of Smith-Lemli-Opitz syndrome (SLOS) are elevated concentrations of the cholesterol precursors 7- and 8-dehydrocholesterol (7- and 8-DHC). We describe a patient with classical SLOS phenotype and oesophageal achalasia, which has not been reported in SLOS patients before. Plasma 7-DHC and 8-DHC were only marginally elevated. The diagnosis was confirmed by sterol analysis in cultured skin fibroblasts and mutation analysis.

Maternal apo E genotype is a modifier of the Smith-Lemli-Opitz syndrome

BACKGROUND

Smith-Lemli-Opitz syndrome (MIM 270400) is an autosomal recessive malformation and mental retardation syndrome that ranges in clinical severity from minimal dysmorphism and mild mental retardation to severe congenital anomalies and intrauterine death. Smith-Lemli-Opitz syndrome is caused by mutations in the Delta7 sterol-reductase gene (DHCR7; EC 1.3.1.21), which impair endogenous cholesterol biosynthesis and make the growing embryo dependent on exogenous (maternal) sources of cholesterol. We have investigated whether apolipoprotein E, a major component of the cholesterol transport system in human beings, is a modifier of the clinical severity of Smith-Lemli-Opitz syndrome.

METHOD

Common apo E, DHCR7, and LDLR genotypes were determined in 137 biochemically characterised patients with Smith-Lemli-Opitz syndrome and 59 of their parents.

RESULTS

There was a significant correlation between patients' clinical severity scores and maternal apo E genotypes (p = 0.028) but not between severity scores and patients' or paternal apo E genotypes. In line with their effects on serum cholesterol levels, the maternal apo epsilon2 genotypes were associated with a severe Smith-Lemli-Opitz syndrome phenotype, whereas apo E genotypes without the epsilon2 allele were associated with a milder phenotype. The correlation of maternal apo E genotype with disease severity persisted after stratification for DHCR7 genotype. There was no association of Smith-Lemli-Opitz syndrome severity with LDLR gene variation.

CONCLUSIONS

These results suggest that the efficiency of cholesterol transport from the mother to the embryo is affected by the maternal apo E genotype and extend the role of apo E and its disease associations to modulation of embryonic development and malformations.

Ossäre Manifestationen und CT-Befunde bei der seltenen Skelettdysplasie Stueve-Wiedemann (SWS)

PURPOSE

Analysis of typical conventional radiological and CT findings in our group of patients with the rare skeletal dysplasia Stueve-Wiedemann-Syndrome (SWS) and comparison with published data.

MATERIALS AND METHODS

In 16 newborns with clinically dysmorphic features, dwarfism, and bowed limbs, radiographs of the chest and skeleton were obtained for classification of the underlying skeletal dysplasia. For the first time, computed tomography was performed for further investigation of midface hypoplasia. The early diagnosis of SWS could be made by correlation of the radiological and clinical findings. For evaluation of progression, follow-up radiological examinations of the skeleton were performed in four children surviving infancy.

RESULTS

Clinically, the newborns with SWS showed dwarfism, midface hypoplasia, bowed extremities with contractures and had severe problems with respiration, feeding, and swallowing as well as episodes of hyperthermia. Skeletal radiographs revealed bowing of the long tubular bones, most pronounced at the lower extremities. Additional findings were internal triangular cortical diaphyseal thickening at the concave side of the bowing, wide metaphyses with abnormal trabecular pattern and radiolucencies. Four patients survived infancy. Clinically, they suffered from recurrent aspiration pneumonia and recurrent episodes of hyperthermia as well as form cutaneous and mucosal infections. The follow-up radiographs showed progressive bowing of the long tubular bones as well as progressive metaphyseal decalcification.

CONCLUSIONS

Skeletal abnormalities in SWS are so characteristic that an early post partum diagnosis can be made. However, a close cooperation between radiologists, clinicians, and geneticists is required for correlation of clinical and radiological findings. The few cases that survive infancy have progressing orthopaedic problems.

Sedation with 4-hydroxybutyric acid: a potential pitfall in the diagnosis of SSADH deficiency

Deficiency of succinic semialdehyde dehydrogenase (SSADH) is a rare neurometabolic disorder with accumulation of 4-hydroxybutyric acid (4-HBA) as a biochemical hallmark. We present a boy with an unresolved severe neurological disorder and intermittent elevation of 4-HBA in serum and CSF which was later shown to result from iatrogenic administration of 4-HBA for sedation purposes.

Further delineation of Raine syndrome

We report o a baby from an Arab family with Raine syndrome. The baby presented at birth with severe craniofacial anomalies including a wide anterior fontanelle, exophthalmos, severe depression of the nasal bridge with a hypoplastic midface, bilateral choanal atresia and a large protruding tongue. All the limbs were short and the thorax was small. Radiologically there was increased bone density in some bones, periosteal new bone formation and marked bowing of the femurs, tibiae, and ulnae. We suggest that osteosclerosis in Raine syndrome is not necessarily severe and generalized, and bowing of the long bones is another variable radiological feature of the syndrome.

Antibiotic resistance of E. coli in sewage and sludge

The aim of the study is the evaluation of resistance patterns of E. coli in wastewater treatment plants without an evaluation of basic antibiotic resistance mechanisms. Investigations have been done in sewage, sludge and receiving waters from three different sewage treatment plants in southern Austria. A total of 767 E. coli isolates were tested regarding their resistance to 24 different antibiotics. The highest resistance rates were found in E. coli strains of a sewage treatment plant which treats not only municipal sewage but also sewage from a hospital. Among the antimicrobial agents tested, the highest resistance rates in the penicillin group were found for Ampicillin (AM) (up to 18%) and Piperacillin (PIP) (up to 12%); in the cephalosporin group for Cefalothin (CF) (up to 35%) and Cefuroxime-Axetil (CXMAX) (up to 11%); in the group of quinolones for Nalidixic acid (NA) (up to 15%); and for Trimethoprime/Sulfamethoxazole (SXT) (up to 13%) and for Tetracycline (TE) (57%). Median values for E. coli in the inflow (crude sewage) of the plants were between 2.0 x 10(4) and 6.1 x 10(4)CFU/ml (Coli ID-agar, BioMerieux 42017) but showed a 200-fold reduction in all three plants in the effluent. Nevertheless, more than 10(2)CFU E. coli/ml reached the receiving water and thus sewage treatment processes contribute to the dissemination of resistant bacteria in the environment.

Stüve-Wiedemann syndrome in children surviving infancy: clinical and radiological features

We report three children from two inbred Arab families with Stüve-Wiedemann syndrome who have survived the first year of life (ages are 6 years, 2.8 years and 2 years). All exhibited a characteristic phenotype resembling that described by Chen et al.[(2001). Am J Med Genet 101:240-245]. In all three children the skeletal abnormalities progressed to severe bowing of the long bones with prominent joints and severe spinal deformity. Neurological symptoms were present in all of them. These included temperature instability with excessive sweating, reduced pain sensation with repeated injury to the tongue and limbs, absent corneal reflexes and a smooth tongue. Mentality was normal in all of them. Radiological changes included under tubulation of the diaphyses, rarefaction and striation of metaphyses, destruction of the femoral heads and spinal deformity. We confirm that survival in this syndrome is possible and that the prognosis improves after the first year of life. This should be taken into consideration when counselling parents of affected children. This report further supports the existence of a characteristic phenotype in Stüve-Wiedemann syndrome survivors which include, in addition to the skeletal abnormalities and distinctive radiological features, neurological symptoms reminiscent of dysautonomia.

CT and MR patterns of hypoxic ischemic brain damage following perinatal asphyxia

The objectives were to study the clinical and neurological abnormalities in children with cerebral palsy and to attempt to correlate the signs with radiological abnormalities detected by CT scan and/or MRI of the brain. In a prospective, hospital-based study, 65 children with cerebral palsy were examined neurologically and their perinatal history was reviewed. Their cranial CT scan, and/or magnetic resonance images were studied. The association between the gestational ages, perinatal history, neurological deficits, and the radiological appearances were studied. Of the 24 preterm-born and 41 term-born children, 23 had spastic diplegia; 57 per cent of these children has significant periventricular leucomalacia, which was more common among preterm-born children. Of the 13 children with hemiplegia, 12 had unilateral lesions on neuroimaging. Spastic tetraplegia was associated with extensive, bilateral, diffuse brain damage. Extrapyramidal cerebral palsy was far more common among term-born infants and 80 per cent of these showed significant abnormalities in the basal ganglia region. Ataxic cerebral palsy was an uncommon variety and there was no significant correlation between neurological signs and abnormalities on brain imaging. In conclusion, the radiological findings were closely related to the type of cerebral palsy and the neurological deficit except in the ataxic type. We believe that CT and MRI imaging are helpful in understanding the pathology and the timing of the lesion in cerebral palsy.

Regulatory roles of the GacS/GacA two-component system in plant-associated and other gram-negative bacteria

The sensor kinase GacS and the response regulator GacA are members of a two-component system that is present in a wide variety of gram-negative bacteria and has been studied mainly in enteric bacteria and fluorescent pseudomonads. The GacS/GacA system controls the production of secondary metabolites and extracellular enzymes involved in pathogenicity to plants and animals, biocontrol of soilborne plant diseases, ecological fitness, or tolerance to stress. A current model proposes that GacS senses a still-unknown signal and activates, via a phosphorelay mechanism, the GacA transcription regulator, which in turn triggers the expression of target genes. The GacS protein belongs to the unorthodox sensor kinases, characterized by an autophosphorylation, a receiver, and an output domain. The periplasmic loop domain of GacS is poorly conserved in diverse bacteria. Thus, a common signal interacting with this domain would be unexpected. Based on a comparison with the transcriptional regulator NarL, a secondary structure can be predicted for the GacA sensor kinases. Certain genes whose expression is regulated by the GacS/GacA system are regulated in parallel by the small RNA binding protein RsmA (CsrA) at a posttranscriptional level. It is suggested that the GacS/GacA system operates a switch between primary and secondary metabolism, with a major involvement of posttranscriptional control mechanisms.

The sigma factor AlgU (AlgT) controls exopolysaccharide production and tolerance towards desiccation and osmotic stress in the biocontrol agent Pseudomonas fluorescens CHA0

A variety of stress situations may affect the activity and survival of plant-beneficial pseudomonads added to soil to control root diseases. This study focused on the roles of the sigma factor AlgU (synonyms, AlgT, RpoE, and sigma(22)) and the anti-sigma factor MucA in stress adaptation of the biocontrol agent Pseudomonas fluorescens CHA0. The algU-mucA-mucB gene cluster of strain CHA0 was similar to that of the pathogens Pseudomonas aeruginosa and Pseudomonas syringae. Strain CHA0 is naturally nonmucoid, whereas a mucA deletion mutant or algU-overexpressing strains were highly mucoid due to exopolysaccharide overproduction. Mucoidy strictly depended on the global regulator GacA. An algU deletion mutant was significantly more sensitive to osmotic stress than the wild-type CHA0 strain and the mucA mutant were. Expression of an algU'-'lacZ reporter fusion was induced severalfold in the wild type and in the mucA mutant upon exposure to osmotic stress, whereas a lower, noninducible level of expression was observed in the algU mutant. Overexpression of algU did not enhance tolerance towards osmotic stress. AlgU was found to be essential for tolerance of P. fluorescens towards desiccation stress in a sterile vermiculite-sand mixture and in a natural sandy loam soil. The size of the population of the algU mutant declined much more rapidly than the size of the wild-type population at soil water contents below 5%. In contrast to its role in pathogenic pseudomonads, AlgU did not contribute to tolerance of P. fluorescens towards oxidative and heat stress. In conclusion, AlgU is a crucial determinant in the adaptation of P. fluorescens to dry conditions and hyperosmolarity, two major stress factors that limit bacterial survival in the environment.

The global posttranscriptional regulator RsmA modulates production of virulence determinants and N-acylhomoserine lactones in Pseudomonas aeruginosa

Posttranscriptional control is known to contribute to the regulation of secondary metabolism and virulence determinants in certain gram-negative bacteria. Here we report the isolation of a Pseudomonas aeruginosa gene which encodes a global translational regulatory protein, RsmA (regulator of secondary metabolites). Overexpression of rsmA resulted in a substantial reduction in the levels of extracellular products, including protease, elastase, and staphylolytic (LasA protease) activity as well as the PA-IL lectin, hydrogen cyanide (HCN), and the phenazine pigment pyocyanin. While inactivation of rsmA in P. aeruginosa had only minor effects on the extracellular enzymes and the PA-IL lectin, the production of HCN and pyocyanin was enhanced during the exponential phase. The influence of RsmA on N-acylhomoserine lactone-mediated quorum sensing was determined by assaying the levels of N-(3-oxododecanoyl)homoserine lactone (3-oxo-C12-HSL) and N-butanoylhomoserine lactone (C4-HSL) produced by the rsmA mutant and the rsmA-overexpressing strain. RsmA exerted a negative effect on the synthesis of both 3-oxo-C12-HSL and C4-HSL, which was confirmed by using lasI and rhlI translational fusions. These data also highlighted the temporal expression control of the lasI gene, which was induced much earlier and to a higher level during the exponential growth phase in an rsmA mutant. To investigate whether RsmA modulates HCN production solely via quorum-sensing control, hcn translational fusions were employed to monitor the regulation of the cyanide biosynthesis genes (hcnABC). RsmA was shown to exert an additional negative effect on cyanogenesis posttranscriptionally by acting on a region surrounding the hcnA ribosome-binding site. This suggests that, in P. aeruginosa, RsmA functions as a pleiotropic posttranscriptional regulator of secondary metabolites directly and also indirectly by modulating the quorum-sensing circuitry.

Th2 cells support intrinsic anti-inflammatory properties of the brain

In experimental autoimmune encephalomyelitis (EAE), Th1 cells are responsible for disease induction while Th2 cells can be protective. To address the mechanisms of this differential behavior, we utilized organotypic murine entorhinal-hippocampal slice cultures to analyze interactions between myelin basic protein-specific Th1 and Th2 cells with microglial cells. While both Th1 and Th2 cells induced CD40 expression, only Th1 cells induced intercellular adhesion molecule-1 (ICAM-1) expression on microglia. Moreover, Th2 cells prevented or even reversed Th1-induced ICAM-1 upregulation. Evidently, Th2 cells could diminish Th1-induced inflammatory reactions and actively support the resting state of microglia, which could be one mechanism of Th2-mediated remission of neuroinflammation during EAE.

Characterization of spontaneous gacS and gacA regulatory mutants of Pseudomonas fluorescens biocontrol strain CHAO

In Pseudomonasfluorescens strain CHAO, the response regulator gene gacA controls expression of extracellular enzymes and antifungal secondary metabolites, which are important for this strain's biocontrol activity in the plant rhizosphere. Two Tn5 insertion mutants of strain CHA0 that had the same pleiotropic phenotype as gacA mutants were complemented by the gacS sensor kinase gene of P. syringae pv. syringae as well as that of P. fluorescens strain Pf-5, indicating that both transposon insertions had occurred in the gacS gene of strain CHA0. This conclusion was supported by Southern hybridisation using a gacS probe from strain Pf-5. Overexpression of the wild-type gacA gene partially compensated for the gacS mutation, however, the overexpressed gacA gene was not stably maintained, suggesting that this is deleterious to the bacterium. Strain CHA0 grown to stationary phase in nutrient-rich liquid media for several days accumulated spontaneous pleiotropic mutants to levels representing 1.25% of the population; all mutants lacked key antifungal metabolites and extracellular protease. Half of 44 spontaneous mutants tested were complemented by gacS, the other half were restored by gacA. Independent point and deletion mutations arose at different sites in the gacA gene. In competition experiments with mixtures of the wild type and a gacA mutant incubated in nutrient-rich broth, the mutant population temporarily increased as the wild type decreased. In conclusion, loss of gacA function can confer a selective advantage on strain CHA0 under laboratory conditions.

Biotic Factors Affecting Expression of the 2,4-Diacetylphloroglucinol Biosynthesis Gene phlA in Pseudomonas fluorescens Biocontrol Strain CHA0 in the Rhizosphere

ABSTRACT Production of the polyketide antimicrobial metabolite 2,4-diacetyl-phloroglucinol (DAPG) is a key factor in the biocontrol activity of Pseudomonas fluorescens CHA0. Strain CHA0 carrying a translational phlA'-'lacZ fusion was used to monitor expression of the phl biosynthetic genes in vitro and in the rhizosphere. Expression of the reporter gene accurately reflected actual production of DAPG in vitro and in planta as determined by direct extraction of the antimicrobial compound. In a gnotobiotic system containing a clay and sand-based artificial soil, reporter gene expression was significantly greater in the rhizospheres of two monocots (maize and wheat) compared with gene expression in the rhizospheres of two dicots (bean and cucumber). We observed this host genotype effect on bacterial gene expression also at the level of cultivars. Significant differences were found among six additional maize cultivars tested under gnotobiotic conditions. There was no difference between transgenic maize expressing the Bacillus thuringiensis insecticidal gene cry1Ab and the near-isogenic parent line. Plant age had a significant impact on gene expression. Using maize as a model, expression of the phlA'-'lacZ reporter gene peaked at 24 h after planting of pregerminated seedlings, and dropped to a fourth of that value within 48 h, remaining at that level throughout 22 days of plant growth. Root infection by Pythium ultimum stimulated bacterial gene expression on both cucumber and maize, and this was independent of differences in rhizosphere colonization on these host plants. To our knowledge, this is the first comprehensive evaluation of how biotic factors that commonly confront bacterial inoculants in agricultural systems (host genotype, host age, and pathogen infection) modulate the expression of key biocontrol genes for disease suppression.

Astrocyte-released cytokines induce ramification and outward K+ channel expression in microglia via distinct signalling pathways

Differentiation of microglial cells is characterized by transformation from ameboid into ramified cell shape and up-regulation of K+ channels. The processes of microglial differentiation are controlled by astrocytic factors. The mechanisms by which astrocytes cause developmental changes in morphological and electrophysiological properties of microglia have remained unclear. We show here that the cytokines transforming growth factor-beta (TGF-beta), macrophage colony-stimulating factor (M-CSF) and granulocyte/macrophage colony-stimulating factor (GM-CSF) are released by astrocytes at concentrations sufficient to induce ramification and up-regulation of delayed rectifier (DR) K+ channels in microglia. Transformation from ameboid into ramified morphology induced in microglia by exposure to astrocyte-conditioned medium (ACM) was inhibited by neutralizing antibodies against TGF-beta, M-CSF or GM-CSF, whilst ACM-induced DR channel expression was exclusively inhibited by antibodies against TGF-beta. Although both ramification and DR channel up-regulation occurred simultaneously, DR channel blockade by charybdotoxin failed to inhibit microglial ramification. The ACM-induced ramification of microglia was inhibited by the tyrosine kinase inhibitor genistein, whereas DR channel up-regulation did not occur in the presence of the serine/threonine kinase inhibitor H7. Our data suggest that astrocytes modulate processes of microglial differentiation in parallel but via distinct signalling pathways.

Leukodepletion for acute lymphocytic leukemia in a three-week-old infant

We report the smallest infant (4.5 kg) to receive leukapheresis as an immediate treatment for Infantile Acute Lymphocytic Leukemia. Leukodepletion helps prevent the risks of hyperviscosity and cerebrovascular and pulmonary leukostasis. In addition, it is a desirable precursor to chemotherapy to potentially reduce metabolic and renal complications associated with rapid cell lysis. Because of this infant's small size, she presented us with multiple concerns, including hypocalcemia from citrate anticoagulation, extracorporeal volume and fluid balance, inlet flow rates. and establishment of adequate interface. Our positive experience in performing this procedure suggests that cytapheresis is a feasible treatment even for very young infants.

Gerodermia osteodysplastica and wrinkly skin syndrome: are they the same?

Gerodermia osteodysplastica (GO) is a connective tissue disorder characterized by premature aging, wrinkled, and lax skin with reduced elasticity which is more marked on the dorsum of the hands and feet associated with hyperextensible joints and osteoporosis. The wrinkly skin syndrome (WSS) is characterized by wrinkled skin over the dorsum of the hands, feet, and abdomen; hyperextensible joints, particularly of the hands; intrauterine growth retardation; postnatal failure to thrive; and mental and developmental delay. We report on five children from two consanguineous Arab families with features overlapping both GO and WSS. All five children had similar dysmorphic facial features consisting of broad and prominent forehead, hypotelorism with epicanthal folds, prominent bulbous nose, flat malar region, and large protruding ears. All had wrinkling of the skin more marked on the dorsum of the hands, feet, and abdomen; hyperextensibility of the joints, particularly of the hands; and aged appearance. Intrauterine growth retardation, subsequent failure to thrive, developmental delay, and variable degree of osteoporosis was also present in all of them. The older three children developed progressive prognathism. We suggest that GO and WSS could represent variable manifestation of the same disorder.

Dual control of hydrogen cyanide biosynthesis by the global activator GacA in Pseudomonas aeruginosa PAO1

The global response regulator GacA of Pseudomonas aeruginosa PAO1 positively controls the production of the quorum sensing signal molecule N-butanoyl-homoserine-lactone (C4-HSL) and hence the synthesis of several C4-HSL-dependent virulence factors, including hydrogen cyanide (HCN). This study presents evidence that GacA positively influences the transcription of the rhlI gene, specifying C4-HSL synthase, explaining the quorum sensing-dependent transcriptional control of the HCN biosynthetic genes (hcnABC). In addition, GacA was found to modulate hcn gene expression positively at a post-transcriptional level involving the hcnA ribosome-binding site. Thus, the activating effect of GacA on cyanogenesis results from both transcriptional and post-transcriptional mechanisms.

Inherited disorders of cholesterol biosynthesis

Defects of cholesterol biosynthesis comprise a heterogeneous group of disorders, most of which have only been recently described and more are likely to follow in the near future. Mevalonic aciduria (MVA) and hyperimmunoglobulinemia D syndrome (HIDS) are due to allelic defects in mevalonate kinase, an enzyme located proximally in the pathway of cholesterol and nonsterol isoprene biosynthesis. Clinically, patients affected with these disorders present with recurrent febrile attacks. This is the only manifestation in most patients with HIDS, and, in the case of classical mevalonic aciduria, is part of a severe multisystemic disease, including malformations, severe failure to thrive and neurological abnormalities. The other recognized defects of cholesterol biosynthesis are due to enzyme defects located distally in the pathway beyond the branching points of nonsterol isoprene biosynthesis and solely affecting cholesterol biosynthesis. Patients with these disorders all present with complex malformation syndromes involving different organ systems. The main characteristics of CHILD syndrome and Conradi-Huenermann syndrome are skeletal defects and ichthyosiform skin involvement. Smith-Lemli-Opitz syndrome and desmosterolosis are generalized malformation syndromes involving many different organs including the central nervous system.The diagnosis of MVA and HIDS is based on determination of mevalonic acid in urine followed by determination of enzyme activity, whereas the search for the distally located defects of cholesterol biosynthesis requires sterol analysis in blood or tissues by GCMS. Rational therapeutic approaches have been described for HIDS, MVA and Smith-Lemli-Opitz syndrome.

The CbrA-CbrB two-component regulatory system controls the utilization of multiple carbon and nitrogen sources in Pseudomonas aeruginosa

A novel two-component system, CbrA-CbrB, was discovered in Pseudomonas aeruginosa; cbrA and cbrB mutants of strain PAO were found to be unable to use several amino acids (such as arginine, histidine and proline), polyamines and agmatine as sole carbon and nitrogen sources. These mutants were also unable to use, or used poorly, many other carbon sources, including mannitol, glucose, pyruvate and citrate. A 7 kb EcoRI fragment carrying the cbrA and cbrB genes was cloned and sequenced. The cbrA and cbrB genes encode a sensor/histidine kinase (Mr 108 379, 983 residues) and a cognate response regulator (Mr 52 254, 478 residues) respectively. The amino-terminal half (490 residues) of CbrA appears to be a sensor membrane domain, as predicted by 12 possible transmembrane helices, whereas the carboxy-terminal part shares homology with the histidine kinases of the NtrB family. The CbrB response regulator shows similarity to the NtrC family members. Complementation and primer extension experiments indicated that cbrA and cbrB are transcribed from separate promoters. In cbrA or cbrB mutants, as well as in the allelic argR9901 and argR9902 mutants, the aot-argR operon was not induced by arginine, indicating an essential role for this two-component system in the expression of the ArgR-dependent catabolic pathways, including the aruCFGDB operon specifying the major aerobic arginine catabolic pathway. The histidine catabolic enzyme histidase was not expressed in cbrAB mutants, even in the presence of histidine. In contrast, proline dehydrogenase, responsible for proline utilization (Pru), was expressed in a cbrB mutant at a level comparable with that of the wild-type strain. When succinate or other C4-dicarboxylates were added to proline medium at 1 mM, the cbrB mutant was restored to a Pru+ phenotype. Such a succinate-dependent Pru+ property was almost abolished by 20 mM ammonia. In conclusion, the CbrA-CbrB system controls the expression of several catabolic pathways and, perhaps together with the NtrB-NtrC system, appears to ensure the intracellular carbon: nitrogen balance in P. aeruginosa.

Tetrahydrobiopterin responsiveness in phenylketonuria differs between patients with the same genotype

Recently, BH(4)-responsive phenylalanine hydroxylase (PAH) deficiency was reported in patients with specific mutations in the PAH gene, and it was suggested that BH(4) responsiveness may be determined by the respective genotypes. We now report on three patients with PAH deficiency and the same genotype but different responses to standardized BH(4) loading. Our results suggest that BH(4) responsiveness in PAH deficiency is at least partly independent from PAH genotype.

Transposase and cointegrase: specialized transposition proteins of the bacterial insertion sequence IS21 and related elements

The bacterial insertion sequence IS21 shares with many insertion sequences a two-step, reactive junction transposition pathway, for which a model is presented in this review: a reactive junction with abutted inverted repeats is first formed and subsequently integrated into the target DNA. The reactive junction occurs in IS21-IS21 tandems and IS21 minicircles. In addition, IS21 shows a unique specialization of transposition functions. By alternative translation initiation, the transposase gene codes for two products: the transposase, capable of promoting both steps of the reactive junction pathway, and the cointegrase, which only promotes the integration of reactive junctions but with higher efficiency. This review also includes a survey of the IS21 family and speculates on the possibility that other members present a similar transpositional specialization.

Essential PchG-dependent reduction in pyochelin biosynthesis of Pseudomonas aeruginosa

The biosynthetic genes pchDCBA and pchEF, which are known to be required for the formation of the siderophore pyochelin and its precursors salicylate and dihydroaeruginoate (Dha), are clustered with the pchR regulatory gene on the chromosome of Pseudomonas aeruginosa. The 4.6-kb region located downstream of the pchEF genes was found to contain three additional, contiguous genes, pchG, pchH, and pchI, probably forming a pchEFGHI operon. The deduced amino acid sequences of PchH and PchI are similar to those of ATP binding cassette transport proteins with an export function. PchG is a homolog of the Yersinia pestis and Y. enterocolitica proteins YbtU and Irp3, which are involved in the biosynthesis of yersiniabactin. A null mutation in pchG abolished pyochelin formation, whereas mutations in pchH and pchI did not affect the amounts of salicylate, Dha, and pyochelin produced. The pyochelin biosynthetic genes were expressed from a vector promoter, uncoupling them from Fur-mediated repression by iron and PchR-dependent induction by pyochelin. In a P. aeruginosa mutant lacking the entire pyochelin biosynthetic gene cluster, the expressed pchDCBA and pchEFG genes were sufficient for salicylate, Dha, and pyochelin production. Pyochelin formation was also obtained in the heterologous host Escherichia coli expressing pchDCBA and pchEFG together with the E. coli entD gene, which provides a phosphopantetheinyl transferase necessary for PchE and PchF activation. The PchG protein was purified and used in combination with PchD and phosphopantetheinylated PchE and PchF in vitro to produce pyochelin from salicylate, L-cysteine, ATP, NADPH, and S-adenosylmethionine. Based on this assay, a reductase function was attributed to PchG. In summary, this study completes the identification of the biosynthetic genes required for pyochelin formation from chorismate in P. aeruginosa.

Micromelic dwarfism--humerus, femur and tibia type

We report a baby with severe micromelic dwarfism characterized by severe shortening of the humeri, femora and tibiae with hypoplastic radii, ulnae and fibulae which are of normal shape. We suggest that this case is similar to the case reported by Baxova et al [(1993), Paediatr Radiol 23:446-449] confirming the identity of this new bone dysplasia.

Manipulation of salicylate content in Arabidopsis thaliana by the expression of an engineered bacterial salicylate synthase

Salicylic acid (SA) plays a central role as a signalling molecule involved in plant defense against microbial attack. Genetic manipulation of SA biosynthesis may therefore help to generate plants that are more disease-resistant. By fusing the two bacterial genes pchA and pchB from Pseudomonas aeruginosa, which encode isochorismate synthase and isochorismate pyruvate-lyase, respectively, we have engineered a novel hybrid enzyme with salicylate synthase (SAS) activity. The pchB-A fusion was expressed in Arabidopsis thaliana under the control of the constitutive cauliflower mosaic virus (CaMV) 35S promoter, with targeting of the gene product either to the cytosol (c-SAS plants) or to the chloroplast (p-SAS plants). In p-SAS plants, the amount of free and conjugated SA was increased more than 20-fold above wild type (WT) level, indicating that SAS is functional in Arabidopsis. P-SAS plants showed a strongly dwarfed phenotype and produced very few seeds. Dwarfism could be caused by the high SA levels per se or, perhaps more likely, by a depletion of the chorismate or isochorismate pools of the chloroplast. Targeting of SAS to the cytosol caused a slight increase in free SA and a significant threefold increase in conjugated SA, probably reflecting limited chorismate availability in this compartment. Although this modest increase in total SA content did not strongly induce the resistance marker PR-1, it resulted nevertheless in enhanced disease resistance towards a virulent isolate of Peronospora parasitica. Increased resistance of c-SAS lines was paralleled with reduced seed production. Taken together, these results illustrate that SAS is a potent tool for the manipulation of SA levels in plants.

Transcriptional control of the hydrogen cyanide biosynthetic genes hcnABC by the anaerobic regulator ANR and the quorum-sensing regulators LasR and RhlR in Pseudomonas aeruginosa

Virulence factors of Pseudomonas aeruginosa include hydrogen cyanide (HCN). This secondary metabolite is maximally produced at low oxygen tension and high cell densities during the transition from exponential to stationary growth phase. The hcnABC genes encoding HCN synthase were identified on a genomic fragment complementing an HCN-deficient mutant of P. aeruginosa PAO1. The hcnA promoter was found to be controlled by the FNR-like anaerobic regulator ANR and by the quorum-sensing regulators LasR and RhlR. Primer extension analysis revealed two transcription starts, T1 and T2, separated by 29 bp. Their function was confirmed by transcriptional lacZ fusions. The promoter sequence displayed an FNR/ANR box at -42.5 bp upstream of T2 and a lux box centered around -42.5 bp upstream of T1. Expression of the hcn genes was completely abolished when this lux box was deleted or inactivated by two point mutations in conserved nucleotides. The lux box was recognized by both LasR [activated by N-(oxododecanoyl)-homoserine lactone] and RhlR (activated by N-butanoyl-homoserine lactone), as shown by expression experiments performed in quorum-sensing-defective P. aeruginosa mutants and in the N-acyl-homoserine lactone-negative heterologous host P. fluorescens CHA0. A second, less conserved lux box lying 160 bp upstream of T1 seems to account for enhanced quorum-sensing-dependent expression. Without LasR and RhlR, ANR could not activate the hcn promoter. Together, these data indicate that expression of the hcn promoter from T1 can occur under quorum-sensing control alone. Enhanced expression from T2 appears to rely on a synergistic action between LasR, RhlR, and ANR.

Human brain-cell death induced by tumour-necrosis-factor-related apoptosis-inducing ligand (TRAIL)

Cell death induced by tumour-necrosis-factor-related apoptosis-inducing ligand (TRAIL) was believed to occur exclusively in tumour cells, suggesting that this drug is safe to use as an antitumour therapy. Concerns were raised, however, when cultured normal human hepatocytes were shown to be susceptible to TRAIL. Here we report that TRAIL induces apoptosis in the human brain. Our finding therefore argues against the use of TRAIL for therapy of human brain tumours. However, neuroinflammatory T cells that express TRAIL might induce apoptosis of brain tissue, indicating a potential target for treatment of multiple sclerosis.

[Waste management--health: a longitudinal study]

Altogether 256 (148 men and 108 women) employees from manual sorting facilities and 120 (98 men and 22 women) employees from compost facilities were examined The main focus of the investigations was in the assessment of the lung-function and the immune-system. A part of employees (87 in sorting and 34 in compost facilities) was observed over a period of 3 years. The lung-function was in the area of the expected values, decreased however from year to year. The concentration of total-IgE increased over the period of 3 years. The observation is from great interest that the difference of the concentration of the total-IgE fluctuated within the 3 years at the employees of manual sorting facilities from +200% to -100% while it amounted to 0% at employees of the compost facilities.

[Comparative studies of airborne, cultivatable microorganisms at selected sites of waste managements, domestic animal husbandry and in the surrounding residential area]

During the last years, sampling of airborne microorganisms (including mesophilic bacteria, moulds, thermophilic bacteria and A. fumigatus) in waste disposal, recycling industry and control sampling locations in the urban and rural districts of Graz was conducted using Andersen 6-stage viable cascade impactors. In the present study additional sampling in livestock buildings has been conducted. Except mesophilic bacteria the emission in the area of waste disposal and recycling industry was significantly higher than in livestock buildings. In the surroundings of the livestock buildings the number of microorganisms was not increased, while the normal background level in the surroundings of the waste proceeding plants was reached from a distance of 150 to 300 meters.

A new syndrome of optic nerve colobomas and renal abnormalities associated with arthrogryposis multiplex

Renal-coloboma syndrome is a developmental disorder involving optic nerve colobomas and renal hypoplasia/insufficiency, which exhibits autosomal dominant inheritance and a highly variable phenotype (OMIM:120330). Mutation in the PAX2 gene was found to result in the renal-coloboma phenotype. We report on an Arab family with autosomal dominant inheritance of a syndrome characterized by a variable combination of optic nerve colobomas, renal abnormalities, vesicoureteral reflux, lax joints and arthrogryposis multiplex. Apart from the arthrogryposis multiplex which has not been described in the renal-coloboma syndrome, the features of the syndrome in this family are very similar to the renal-coloboma syndrome. However sequencing of all 12 axons of PAX2 gene revealed no mutation in this family. The disorder in this family is likely to represent a new syndrome with features overlapping with the renal-coloboma syndrome.

Multicopy suppression of a gacA mutation by the infC operon in Pseudomonas fluorescens CHA0: competition with the global translational regulator RsmA

The gacA gene of the biocontrol strain Pseudomonas fluorescens CHA0 codes for a response regulator which, together with the sensor kinase GacS (=LemA), is required for the production of exoenzymes and secondary metabolites involved in biocontrol, including hydrogen cyanide (HCN). A gacA multicopy suppressor was isolated from a cosmid library of strain CHA0 and identified as the infC-rpmI-rplT operon, which encodes the translation initiation factor IF3 and the ribosomal proteins L35 and L20. The efficiency of suppression was about 30%, as determined by the use of a GacA-controlled reporter construct, i.e. a translational hcnA'-'lacZ fusion. Overexpression of the rsmA gene (coding for a global translational repressor) reversed the suppressive effect of the amplified infC operon. This finding suggests that some product(s) of the infC operon can compete with RsmA at the level of translation in P. fluorescens CHA0 and that important biocontrol traits can be regulated at this level.