Draft Genome Sequence of Nitrincola sp. Strain A-D6, an Arsenic-Resistant Gammaproteobacterium Isolated from a Salt Flat.

We report Nitrincola sp. strain A-D6, which was characterized as an arsenic-resistant bacterium isolated from the Ascotán Salt Flat in northern Chile. The size of the genome is 3,795,776 bp, with a G+C content of 49.

Diversity of the basic defect of homozygous CFTR mutation genotypes in humans.

Background: Knowledge of how CFTR mutations other than F508del translate into the basic defect in cystic fibrosis (CF) is scarce due to the low incidence of homozygous index cases.

Methods: 17 individuals who are homozygous for deletions, missense, stop or splice site mutations in the CFTR gene were investigated for clinical symptoms of CF and assessed in CFTR function by sweat test, nasal potential difference and intestinal current measurement.

Results: CFTR activity in sweat gland, upper airways and distal intestine was normal for homozygous carriers of G314E or L997F and in the range of F508del homozygotes for homozygous carriers of E92K, W1098L, R553X, R1162X, CFTRdele2(ins186) or CFTRdele2,3(21 kb).

Hearing loss in infantile Pompe's disease and determination of underlying pathology in the knockout mouse.

Hearing deficit occurs in several lysosomal storage disorders but has so far not been recognized as a symptom of Pompe's disease (glycogen storage disease type II). We discovered quite unexpectedly 30-90 dB hearing loss in four infants with Pompe's disease, who participated in a study on the safety and efficacy of enzyme replacement therapy. Three other patients with juvenile Pompe's disease did not have this symptom.

Cystic fibrosis transmembrane conductance regulator (CFTR)-mediated residual chloride secretion does not protect against early chronic Pseudomonas aeruginosa infection in F508del homozygous cystic fibrosis patients.

Cystic fibrosis (CF) disease severity is characterized by a broad variability that has been attributed, in addition to the CF transmembrane conductance regulator (CFTR) genotype, to modulating factors such as CFTR-mediated residual chloride (Cl-) secretion. Moreover, CFTR has been suggested to function as a receptor for Pseudomonas aeruginosa (PA). In this study, we investigated whether or not the presence of residual Cl- secretion protects against early chronic PA colonization of patients' airways.

Deformation of network connectivity in the inferior olive of connexin 36-deficient mice is compensated by morphological and electrophysiological changes at the single neuron level.

Compensatory mechanisms after genetic manipulations have been documented extensively for the nervous system. In many cases, these mechanisms involve genetic regulation at the transcription or expression level of existing isoforms. We report a novel mechanism by which single neurons compensate for changes in network connectivity by retuning their intrinsic electrical properties.

Chloride conductance and genetic background modulate the cystic fibrosis phenotype of Delta F508 homozygous twins and siblings.

To investigate the impact of chloride (Cl(-)) permeability, mediated by residual activity of the cystic fibrosis transmembrane conductance regulator (CFTR) or by other Cl(-) channels, on the manifestations of cystic fibrosis (CF), we determined Cl(-) transport properties of the respiratory and intestinal tracts in Delta F508 homozygous twins and siblings. In the majority of patients, cAMP and/or Ca(2+)-regulated Cl(-) conductance was detected in the airways and intestine. Our finding of cAMP-mediated Cl(-) conductance suggests that, in vivo, at least some Delta F508 CFTR can reach the plasma membrane and affect Cl(-) permeability.

Categories of deltaF508 homozygous cystic fibrosis twin and sibling pairs with distinct phenotypic characteristics.

Cystic fibrosis (CF), the most common severe autosomal recessive trait among Caucasians, is caused by molecular lesions in the cystic fibrosis transmembrane conductance regulator gene (CFTR). The course of the multi-organ disease CF is highly variable, suggesting the influence of environmental factors and/or modulating genes other than CFTR on the disease phenotype. To evaluate the cause of CF disease variability, the European CF Twin and Sibling Study collected data on two clinical parameters most sensitive for the course and prognosis of CF, ie weight predicted for height (wfh)% (representative for the nutritional status) and FEVPerc (representative for the pulmonary status) for a cohort of 277 sibling pairs, 12 pairs of dizygous twins and 29 pairs of monozygous twins.

Residual chloride secretion in intestinal tissue of deltaF508 homozygous twins and siblings with cystic fibrosis. The European CF Twin and Sibling Study Consortium.

Background & Aims: Cholinergic stimulation of chloride secretion is impaired in the intestines of patients with cystic fibrosis (CF). However, intestinal chloride secretion has been observed in patients with mild CF mutations. The aim of this study was to investigate residual Cl(-) secretion in the intestine of DeltaF508 homozygous CF patients, and examine the contribution of cystic fibrosis transmembrane conductance regulator (CFTR) and alternative Cl(-) conductances.

Clinical presentation of exclusive cystic fibrosis lung disease.

The diagnosis of cystic fibrosis (CF) is based on the occurrence of two mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene and on assays that measure the basic defect of abnormal chloride transport in the affected organs. However, in cases of atypical CF not all diagnostic tests may be positive. We present a patient with an atypical CF phenotype in whom the only presenting symptom was severe CF-like lung disease substantiated by an abnormal nasal potential difference.

Cystic-fibrosis-like disease unrelated to the cystic fibrosis transmembrane conductance regulator.

Cystic fibrosis (CF) is considered to be a monogenic disease caused by molecular lesions within the cystic fibrosis transmembrane conductance regulator (CFTR) gene and is diagnosed by elevated sweat electrolytes. We have investigated the clinical manifestations of cystic fibrosis, CFTR genetics and electrophysiology in a sibpair in which the brother is being treated as having CF, whereas his sister is asymptomatic. The diagnosis of CF in the index patient is based on highly elevated sweat electrolytes in the presence of CF-related pulmonary symptoms.

Genistein activates CFTR Cl- channels via a tyrosine kinase- and protein phosphatase-independent mechanism.

Previous studies have revealed an adenosine 3',5'-cyclic monophosphate (cAMP)-independent activation of cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channels by the tyrosine kinase inhibitor genistein. To further explore its mechanism of action, we have reconstituted genistein activation of CFTR in excised inside-out membrane patches. In the presence or absence of ATP, genistein appeared unable to open silent CFTR Cl- channels.

Cystic fibrosis transmembrane conductance regulator mediates the cyclic adenosine monophosphate-induced fluid secretion but not the inhibition of resorption in mouse gallbladder epithelium.

We have studied the physiological role of the cystic fibrosis (CF) gene product (cystic fibrosis transmembrane conductance regulator [CFTR]) in gallbladder epithelium using a knockout mouse model for CF. We found that normal mouse gallbladder epithelium expresses functional CFTR as shown by reverse-transcription polymerase chain reaction (RT-PCR) analysis and Ussing chamber experiments. Gallbladders from Cftr -/- mice were structurally intact as shown by microscopic and physiological parameters but lacked the cyclic adenosine monophosphate (cAMP)-induced chloride current observed in normal gallbladders.

CFTR expression and mucin secretion in cultured mouse gallbladder epithelial cells.

Dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) in humans is frequently associated with progressive liver disease, which appears to result from obstruction of biliary ducts with mucous material. CFTR in the liver is expressed in the biliary epithelium. With the use of a mouse model for cystic fibrosis (CF) we have studied the relationship between CFTR expression and glycoprotein secretion in primary culture of mouse gallbladder epithelial cells (MGBC) MGBC in culture maintain a well-differentiated phenotype as shown by microscopy.

In vivo measurement of chloride and water secretion in the jejunum of cystic fibrosis patients.

In the present study, we have investigated the possible consequences of the chloride channel defect in the intestine of cystic fibrosis (CF) patients for electrolyte and water transport in the jejunum in vivo, using a multilumen, double occluding balloon catheter, and an Ag/AgCl intraluminal electrode. During a chloride-free perfusion, to optimize the sensitivity of our measurements, the transmural potential difference (PD) (lumen with reference to serosal side) was found to be significantly higher in the jejunum of CF patients (+8.0 +/- 2.

A delta F508 mutation in mouse cystic fibrosis transmembrane conductance regulator results in a temperature-sensitive processing defect in vivo.

The most prevalent mutation (delta F508) in cystic fibrosis patients inhibits maturation and transfer to the plasma membrane of the mutant cystic fibrosis transmembrane conductance regulator (CFTR). We have analyzed the properties of a delta F508 CFTR mouse model, which we described recently. We show that the mRNA levels of mutant CFTR are normal in all tissues examined.

Isotype-specific activation of cystic fibrosis transmembrane conductance regulator-chloride channels by cGMP-dependent protein kinase II.

Type II cGMP-dependent protein kinase (cGKII) isolated from pig intestinal brush borders and type I alpha cGK (cGKI) purified from bovine lung were compared for their ability to activate the cystic fibrosis transmembrane conductance regulator (CFTR)-Cl- channel in excised, inside-out membrane patches from NIH-3T3 fibroblasts and from a rat intestinal cell line (IEC-CF7) stably expressing recombinant CFTR. In both cell models, in the presence of cGMP and ATP, cGKII was found to mimic the effect of the catalytic subunit of cAMP-dependent protein kinase (cAK) on opening CFTR-Cl-channels, albeit with different kinetics (2-3-min lag time, reduced rate of activation). By contrast, cGKI or a monomeric cGKI catalytic fragment was incapable of opening CFTR-Cl- channels and also failed to potentiate cGKII activation of the channels.

A mouse model for the cystic fibrosis delta F508 mutation.

Most cystic fibrosis (CF) patients produce a mutant form (delta F508) of the cystic fibrosis transmembrane conductance regulator (CFTR), which is not properly processed in normal cells but is active as a chloride channel in several experimental systems. We used a double homologous recombination ('Hit and Run') procedure to generate a mouse model for the delta F508 mutation. Targeted embryonic stem (ES) cells (Hit clones) were found; of these either 80 or 20% of the clones had lost the delta F508 mutation, depending on the distance between the linearization site in the targeting construct and the delta F508 mutation.

Chronic hypokalaemia of adults: Gitelman's syndrome is frequent but classical Bartter's syndrome is rare.

We evaluated 27 adult patients with chronic hypokalaemia (K+ = 2.9 +/- 0.2 mmol/l), documented over at least 5 years, in whom the cause of the hypokalaemia had not been clarified in spite of previous testing.

Determinants of mild clinical symptoms in cystic fibrosis patients. Residual chloride secretion measured in rectal biopsies in relation to the genotype.

Previous Ussing chamber measurements of secretagogue-provoked changes in short circuit current in rectal suction biopsies of cystic fibrosis (CF) patients showed that in a minority of patients chloride secretion in response to cholinergic agonists is reduced but not completely absent. To assess a possible relationship between this phenomenon and both the genotype and the phenotype, we performed Ussing chamber experiments on rectal suction biopsies of 51 CF patients. The CF mutation was identified in 89 out of 102 CF alleles.

Synergistic activation of non-rectifying small-conductance chloride channels by forskolin and phorbol esters in cell-attached patches of the human colon carcinoma cell line HT-29cl.19A.

Cell-attached patch-clamp studies with the human colon carcinoma HT-29cl.19A cells revealed a small chloride channel with a unitary conductance of 6.5 pS at 70 mV and 4.

The value of in vivo electrophysiological measurements for monitoring functional adaptation after massive small bowel resection in the rat.

The process of functional adaptation after extensive small bowel resection is complex and imprecisely understood. In vivo electrophysiological measurements for monitoring the functional adaptive process after massive small bowel resection in Brown-Norway rats were evaluated. Rats underwent either a sham operation (SH) or a 90% small bowel resection (SB).

Calcium ionophore plus excision induce a large conductance chloride channel in membrane patches of human colon carcinoma cells HT-29cl.19A.

In excised inside-out membrane patches of the human colon carcinoma HT-29cl.19A cells a large conductance (373 +/- 10 pS) chloride channel was found. Channel activity could only be observed after excision of patches from cells incubated with calcium ionophore.

Regulation of chloride channels in the human colon carcinoma cell line HT29.cl19A.

Chloride (Cl-) channels are important in the regulation of salt and water transport in secretory epithelial cells. A disturbed Cl- secretion is the most consistent characteristic in the genetic disease cystic fibrosis. An outwardly rectifying Cl- channel (OR) with a conductance of 25-50 pS had been proposed to play a major role in Cl- secretion.

Low-conductance chloride channels in IEC-6 and CF nasal cells expressing CFTR.

The properties of the cystic fibrosis gene product (CFTR) were studied by expression of cloned cDNA in different cell systems. Infection of both simian fibroblast (Vero) cells and immortalized CF nasal polyp cells (NCF3A) with a vaccinia virus encoding CFTR induced forskolin-induced Cl- permeability and low-conductance (8 pS) Cl- channels. By stable transfection of the rat intestinal crypt-derived cell line IEC-6 we have isolated a clone, IEC-CF7, which expresses CFTR mRNA and antigen.