Molecular characterization of a heme-binding protein of Bacteroides fragilis BE1

An iron-repressible 44-kDa outer membrane protein plays a crucial role in the acquisition of heme by the anaerobic bacterium Bacteroides fragilis. The DNA sequence of the gene encoding the 44-kDa protein (hupA) was determined. The hupA gene encodes a protein of 431 amino acid residues with a calculated molecular mass of 48,189 Da. The hupA gene is preceded by an open reading frame of 480 bp that probably encodes a protein with a calculated molecular mass of 18,073 Da. hupA and this open reading frame are likely organized in an operon, and a sequence homologous to the Escherichia coli consensus Fur box was present in the putative promoter region of the operon. Heme-binding studies showed that HupA binds heme. Analysis of the deduced amino acid sequence revealed signature heme-binding consensus motifs, characteristic of heme lyases. Subcellular localization studies in E. coli revealed that HupA was mainly found in the cytoplasmic membrane but not in the outer membrane of E. coli. This suggested that B. fragilis uses another strategy for the translocation of this outer membrane protein across its cell envelope than E. coli does. HupA did not have significant homology with other putative bacterial heme receptors.     

A genomic region of lactococcal temperate bacteriophage TP901-1 encoding major virion proteins

Two major structural proteins, MHP (major head protein) and MTP (major tail protein), from the lactococcal temperate phage TP901-1 were sequenced at their amino acid termini, and derived degenerate oligonucleotides were used to locate the corresponding genes in the phage genome. This genomic region was sequenced. The sequence characterized includes a total of 11 open reading frames (ORFs) showing an operon structure. Upstream of each ORF, except ORF b2 and ORF x, potential ribosome-binding sites were found, suggesting independent translation. However, coupled translation is suggested for ORF x and as a possibility for ORF b3 and ORF c2, which have ribosome-binding sites located more distant from their start codons. ORF b2 may be translationally fused with mhp at a low frequency. The mhp and mtp genes are transcribed as a 3.7-kb mRNA with at least six additional ORFs. The organization of the genomic region analyzed resembles that of other distantly related phages, providing possible roles for the uncharacterized ORFs.     

Intravitreal tolerance of a new perfluorocarbon vitreous replacement, Multifluor APF-144

OBJECTIVE: To evaluate the intravitreal tolerance of a new perfluorocarbon vitreous replacement, Multifluor APF-144 (perfluorotetramethylcyclohexane). DESIGN: Ten New Zealand albino rabbits (one eye from each) underwent vitrectomy. The vitreous was replaced in five eyes with Multifluor APF-144 and in five eyes with saline (control group). OUTCOME MEASURES: Appearance on indirect ophthalmoscopy, electroretinography recordings before and 2, 4 and 8 weeks after vitrectomy, findings on electron and light microscopy at 8 weeks. RESULTS: Endophthalmitis did not develop in any of the eyes. There was no significant change in electroretinography values for the experimental eyes after vitrectomy. No evidence of retinal toxicity was found on light or electron microscopic examination. CONCLUSIONS: Multifluor APF-144 shows promise as a short-term postoperative retinal tamponading agent.     

Absence of bacteremia and endotoxemia despite contaminated dialyzate

Fevers associated with hemodialysis have been attributed to the transfer of relatively large endotoxin molecules and/or bacteria from contaminated dialyzate across the dialyzing membrane. We evaluated 27 patients during hollow-fiber dialysis when, due to a malfunction, dialysis fluids contained bacteria and endotoxin at levels previously reported to be associated with pyrogenic reactions. Neither endotoxin nor bacteria was detected in 54 venous and arterial blood specimens collected at the termination of hemodialysis. Temperature elevations did not occur during or within 1/2 hr after dialysis. In an extended study, 20 dialyzers were collected after single patient use and the dialyzate compartment was filled with highly contaminated dialyzate, while the blood compartment was filled with sterile pyrogen-free saline. Following 5 to 7 days incubation, bacteria were present in the blood compartments of 4 of 20 dialyzers, probably due to contamination during dialyzer handling. However, the much smaller endotoxin molecule could not be detected in the absence of bacterial contamination. These results indicate that the intact cellophane membrane is an effective barrier to endotoxin and bacteria under clinical conditions.     

Conservative therapy of angina pectoris using nifedipine (Adalat)

35 patients with angina pectoris or previous myocardial infarction were treated for the period of 6 weeks with a new calcium-antagonist (4-2'-Nitrophenyl-2,6-Dimethyl 1,4-dihydro-pyridin-3,5-dicarbon acid dimethylester) Adalat. The attacks of angina pectoris decreased by 75 percent, the need for nitroglycerin decreased by 84 percent. Examination at rest and under exercise before and during the treatment with Adalat showed when registered by electrocardiogram and by the mean pulmonary-capillary pressure a better tolerance under exercise during treatment as well as a decrease of the PCPm in rest and under exercise after 6 week-therapy with Adalat. No improvement during the period of treatment was seen in 2 patients, who suffered from a severe diffuse type of coronary artery disease.     

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