Identification of vegetative proteins for a two-dimensional protein index of Bacillus subtilis

Twenty-three of the most prominent spots which are visible on two-dimensional (2-D) protein gels of Bacillus subtilis crude extracts were selected as marker spots for the construction of a 2-D protein index. N-terminal sequencing of the corresponding proteins resulted in the identification of enzymes involved in glycolysis, TCA cycle, pentose phosphate cycle, amino acid metabolism, nucleotide biosynthesis and translation. Using computer analysis of the 2-D protein gels, most of these metabolic enzymes were found to be synthesized at a reduced rate after different stresses and glucose starvation. Such an approach permits a rapid and global evaluation of the regulation of different branches of metabolism in response to various physiological conditions.

Specific and general stress proteins in Bacillus subtilis--a two-deimensional protein electrophoresis study

A computer-aided analysis of high resolution two-dimensional polyacrylamide gels was used to investigate the changes in the protein synthesis profile in B. subtilis wild-type strains and sigB mutants in response to heat shock, salt and ethanol stress, and glucose of phosphate starvation. The data provided evidence that the induction of a least 42 general stress proteins absolutely required the alternative sigma factor sigmaB. However, at least seven stress proteins, among them ClpC, ClpP, Sod, AhpC and AhpF, remained stress-inducible in a sigB mutant. Such a detailed analysis also premitted the description of subgroups of general stress proteins which are subject to additional regulatory circuits, indicating a very thorough fine-tuning of this complex response. The relative synthesis rate of the general stress proteins constituted up to 40% of the total protein synthesis of stressed cells and thereby emphasizes the importance of the stress regulon. Besides the induction of these general or rather unspecific stress proteins, the induction of stress-specific proteins is shown and discussed.

The open conformation of a Pseudomonas lipase

BACKGROUND

. The interfacial activation of lipases results primarily from conformational changes in the enzymes which expose the active site and provide a hydrophobic surface for interaction with the lipid substrate. Comparison of the crystallization conditions used and the structures observed for a variety of lipases suggests that the enzyme conformation is dependent on solution conditions. Pseudomonas cepacia lipase (PCL) was crystallized in conditions from which the open, active conformation of the enzyme was expected. Its three-dimensional structure was determined independently in three different laboratories and was compared with the previously reported closed conformations of the closely related lipases from Pseudomonas glumae (PGL) and Chromobacterium viscosum (CVL). These structures provide new insights into the function of this commercially important family of lipases.

RESULTS

. The three independent structures of PCL superimpose with only small differences in the mainchain conformations. As expected, the observed conformation reveals a catalytic site exposed to the solvent. Superposition of PCL with the PGL and CVL structures indicates that the rearrangement from the closed to the open conformation involves three loops. The largest movement involves a 40 residue stretch, within which a helical segment moves to afford access to the catalytic site. A hydrophobic cleft that is presumed to be the lipid binding site is formed around the active site.

CONCLUSIONS

. The interfacial activation of Pseudomonas lipases involves conformational rearrangements of surface loops and appears to conform to models of activation deduced from the structures of fungal and mammalian lipases. Factors controlling the conformational rearrangement are not understood, but a comparison of crystallization conditions and observed conformation suggests that the conformation of the protein is determined by the solution conditions, perhaps by the dielectric constant.

An internal FK506-binding domain is the catalytic core of the prolyl isomerase activity associated with the Bacillus subtilis trigger factor

Two major families of peptidylprolyl cis-trans-isomerases, the cyclophilins and the structurally unrelated FK506-binding proteins (FKBPs), have been identified as cellular factors involved in protein folding in vitro. Here we report on the biochemical characterization of a second prolyl isomerase of Bacillus subtilis that was purified from a cyclophilin-negative (ppiB null) mutant and was shown to be the trigger factor (TigBS). N-terminal sequencing of 27 amino acid residues of the purified protein revealed 100% identity to the deduced sequence encoded by the tig gene, sequenced as a part of the B. subtilis genome project. The tigBS gene, located at 246 degrees on the genetic map upstream of the clpX and lonA,B genes, encodes an acidic protein (pI 4.3) of 47.5 kDa. Purified and recombinant TigBS-His proteins share the same substrate specificity and catalytic activity (Kcat/K(m) of 1.5 microM-1 s-1); both are inhibited by the macrolide FK506 with IC50 the range of 500 nM. We also demonstrate that the prolyl isomerase activity of TigBS is mediated by an internal domain of about 13 kDa (homologous to FKPB12) that represents the catalytic core of the trigger factor.

Laparoscopic anterior extended seromyotomy with posterior truncal vagotomy: an experimental study

We describe a new laparoscopic modification of parietal cell vagotomy. The laparoscopic anterior extended seromyotomy with posterior truncal vagotomy was performed in five pigs weighing 21 to 25 kg each. Congo-red and pH tests were undertaken 2 weeks later by open gastrotomy. The photographs of the stained gastric mucosa made at the 5-min interval after Congo-red administration were analyzed with a computer-driven area calculation program. Preoperative and postoperative weights were taken for all animals. The experimental parietal cell vagotomy group was compared with the sham group and showed a minimal amount of nondenervated parietal cell mass (0.9 +/- 0.4% versus 28.2 +/- 3.9%, p < 0.05). The pH values showed an inhibition of gastric acid secretion (7.8 +/- 0.7 versus 2.2 +/- 0.4, p < 0.05). During postoperative follow-up, no significant difference in the weight increase of the experimental and the sham control group was noticed (1.6 +/- 0.6 kg versus 2.0 +/- 0.1 kg, p < 0.27). The laparoscopic anterior extended seromyotomy with posterior truncal vagotomy efficiently suppresses gastric acid secretion, preserving the motility of the antrum and pylorus and diminishing the risk of residual areas of innervation. This procedure avoids dissection of the esophagus and can provide an easier but equally effective operative treatment of ulcer disease compared with other types of parietal cell vagotomy.

Copurification of ribosomal protein S2 and DNA-dependent RNA polymerase from heat-shocked cells of Bacillus subtilis

The DNA-dependent RNA polymerases from heat-shocked and vegetatively grown cells of Bacillus subtilis were isolated and compared. The RNA polymerase from non-stressed cells had the well known alpha, beta, beta' and sigma composition of eubacterial RNA polymerases. The RNA polymerase from heat-shocked cells exhibited one additional band shown by SDS-PAGE. N-terminal sequencing of the first 16 amino acids of the associated protein demonstrated its identity with the ribosomal protein S2.

General and oxidative stress responses in Bacillus subtilis: cloning, expression, and mutation of the alkyl hydroperoxide reductase operon

The AhpC subunit of the Bacillus subtilis alkyl hydroperoxide reductase was identified as a general stress protein induced in response to heat or salt stress or after entry of the organism into the stationary phase. The ahp operon, encoding the two subunits AhpC and AhpF, was cloned and localized between the gntRKPZ operon and the bglA locus. Two-dimensional gel analyses revealed an especially strong induction of AhpC and AhpF in cells subjected to oxidative stress. Transcriptional studies showed a 3- to 4-fold induction of ahp mRNA after heat or salt stress or starvation for glucose and a 20-fold induction by oxidative stress, thus confirming the protein induction data for AhpC and AhpF. Stress induction occurred at a sigmaA-dependent promoter that overlaps with operator sites similar to the per box. Compared with the wild type, the ahpC mutant was resistant to hydrogen peroxide because of the derepression of the peroxide regulon (N. Bsat, L. Chen, and J. D. Helmann, J. Bacteriol. 178:6579-6586, 1996) but more sensitive to cumene hydroperoxide (CHP) during exponential growth. In contrast, stationary-phase wild-type and ahpC mutant cells displayed complete resistance to treatment with 1 mM CHP. Moreover, a sigmaB mutant was found to be extremely sensitive to CHP during vegetative growth and in stationary phase, which indicates that sigmaB-dependent general stress proteins are involved in the protection of cells against oxidative stress.

Diagnostic and prognostic value of cerebral 31P magnetic resonance spectroscopy in neonates with perinatal asphyxia

The impact of depressed neonatal cerebral oxidative phosphorylation for diagnosing the severity of perinatal asphyxia was estimated by correlating the concentrations of phosphocreatine (PCr) and ATP as determined by magnetic resonance spectroscopy with the degree of hypoxic-ischemic encephalopathy (HIE) in 23 asphyxiated term neonates. Ten healthy age-matched neonates served as controls. In patients, the mean concentrations +/- SD of PCr and ATP were 0.99 +/- 0.46 mmol/L (1.6 +/- 0.2 mmol/L) and 0.99 +/- 0.35 mmol/L (1.7 +/- 0.2 mmol/L), respectively (normal values in parentheses). [PCr] and [ATP] correlated significantly with the severity of HIE (r = 0.85 and 0.9, respectively, p < 0.001), indicating that the neonatal encephalopathy is the clinical manifestation of a marred brain energy metabolism. Neurodevelopmental outcome was evaluated in 21 children at 3, 9, and 18 mo. Seven infants had multiple impairments, five were moderately handicapped, five had only mild symptoms, and four were normal. There was a significant correlation between the cerebral concentrations of PCr or ATP at birth and outcome (r = 0.8, p < 0.001) and between the degree of neonatal neurologic depression and outcome (r = 0.7). More important, the outcome of neonates with moderate HIE could better be predicted with information from quantitative 31P magnetic resonance spectroscopy than from neurologic examinations. In general, the accuracy of outcome predictability could significantly be increased by adding results from 31P magnetic resonance spectroscopy to the neonatal neurologic score, but not vice versa. No correlation with outcome was found for other perinatal risk factors, including Apgar score.

Biochemical identification of a lipoprotein with maltose-binding activity in the thermoacidophilic Gram-positive bacterium Alicyclobacillus acidocaldarius

Growth of the thermoacidophilic Gram-positive bacterium Alicyclobacillus acidocaldarius strain ATCC 27009 on maltose resulted in the increased production of a protein with apparent molecular mass of 40 kDa. By metabolic labelling with 14C-palmitic acid, the 40-kDa protein was identified as a lipoprotein. The protein exhibited maltose-binding activity at pH 3.5, as demonstrated by chromatography on cross-linked amylose. Partial amino acid sequence analysis revealed that the 40-kDa protein corresponds to the product of an open reading frame downstream from the amylase gene (amy) that displays similarity to enterobacterial maltose-binding proteins.

Analyte and label binding assay read by flow cytometry

A new immunometric two-site sandwich assay is introduced, in which a label-scavenging binding partner is added to the sample in addition to the analyte-binding partner. The scavenger binding partner binds excess label antibody, giving a signal proportional to the amount of excess label antibody in the sample solution. A set of two calibration curves is obtained from the two binding partners simultaneously, and a combination of the two signals gives an unambiguous determination of the analyte concentration, even for high analyte concentrations where the hook effect may occur. Two-particle immunofluorometric assays developed for placental alkaline phosphatase and human chorionic gonadotropin on the basis of this principle and yielding signals measured by flow cytometry gave rapid results (2 h) and had working ranges in excess of 5 and 6 orders of magnitude for the respective analytes.

After antagonization of acute opiate overdose: a survey at hospitals in Vienna

This study describes the clinical management and characteristics of people who, following acute opioid overdose, are taken to hospital after efficient antagonization by the pre-hospital emergency service. In addition, it defines areas of interest for further research. Over a 4-month period (September-December 1993) we collected data by a structured protocol sheet on patients' characteristics, anamnestic data on abuse and emergencies, clinical presentation, treatment by specific antidote and routine laboratory investigations. Outcome was verified by retrospective review of prehospital and forensic data. We studied 77 subjects, predominantly young males, who were involved in 83 emergencies, mostly occurring at weekends. In more than 60% of cases a single administration of specific antidote sufficed to stabilize the patients; 64% of patients left hospital against medical advice after an average stay of less than 6 hours; 46% denied daily opioid abuse and half the subjects, especially younger drug-users, seemed interested in counselling. This hospital-based study did not provide reliable data on the epidemiology of opioid overdose. Clinical management is determined by experience, pragmatism and beliefs. Efforts towards secondary prevention of drug problems at emergency departments might be warranted, and further research on pattern and management of opioid overdose is needed.

Analyte and label binding assay read by flow cytometry

A new immunometric two-site sandwich assay is introduced, in which a label-scavenging binding partner is added to the sample in addition to the analyte-binding partner. The scavenger binding partner binds excess label antibody, giving a signal proportional to the amount of excess label antibody in the sample solution. A set of two calibration curves is obtained from the two binding partners simultaneously, and a combination of the two signals gives an unambiguous determination of the analyte concentration, even for high analyte concentrations where the hook effect may occur. Two-particle immunofluorometric assays developed for placental alkaline phosphatase and human chorionic gonadotropin on the basis of this principle and yielding signals measured by flow cytometry gave rapid results (2 h) and had working ranges in excess of 5 and 6 orders of magnitude for the respective analytes.

[Sudden vertigo--differential diagnosis and therapy in peripheral vestibular (inner ear-induced) forms]

The most important forms of inner ear disorders manifesting as sudden vertigo may be distinguished by the duration of the vertiginous spells: sudden vertigo, diminishing during days = acute peripheral vestibulopathy, recurrent spells lasting for hours = Ménière's disease, recurrent vertigo lasting for minutes = "vascular', recurrent positioning-induced vertigo lasting for seconds = benign paroxysmal positioning vertigo (BPPV). In the last years, major progress was made in the treatment of BPPV. Based on new ideas on the underlying pathomechanism, this most common form of vestibular vertigo now can be treated definitively in most patients within a few minutes by a simple maneuver (canalith reposition maneuver by Epley/Parnes). This procedure is presented in this paper.

[Cost reduction in long-term nursing thanks to a memory clinic--results of a case control study]

Between 1991 and 1995, 334 persons from the city of Zurich have been investigated at the gerontologic counselling facility of the memory clinic of the nursing home Entlisberg near Zurich. 49 (14.7%) of these persons suffered from a treatable disease (16 from depression, 13 from chronic intoxication, 20 from other treatable diseases), 10 from other disturbances (debility or postapoplectic state), and 275 from dementia. In 45% of the cases dementia was moderate, in 47% moderate to severe, and in 8% severe. In most cases dementia was of Alzheimer's type (60.7%), others were of multi-infarct type (17.5%), of mixed type (13.1%), or other types (8.7%). Until march 1996, 64 (19.4%) of these 334 on the average 74-year-old persons treated in the memory clinic have been admitted to a city nursing home. They have compared to a random sample, including 312 demented persons of similar ages and similar date of admittance to the same institutions. The proportion of demented persons cared before admittance by a spouse was about 28% in both groups. On an average, the mini mental state (Zurich variant) at admittance to a nursing home was 10.95 points in patients from the memory clinic, compared to 13.43 points in the control group. Thus, patients that have formerly been advised and trained entered the nursing home in a state of dementia more advanced by 2.48 points. Based on an average yearly demelioration by about 2.4 points, this means admittance to a nursing home is delayed by 376 days. Patients for whom admittance to a nursing home could be avoided completely by the treatment proposed by the counselling were not considered in this calculation.