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A series of fluorescent oligonucleotide probes that can hybridize with unique sequences of the small subunit (SSU) ribosomal RNA (rRNA) of Paraphysomonas vestita were prepared for bacterial identification. The fluorescent oligonucleotide probes specifically bonded to Paraphysomonas vestita and imparted a strong fluorescence to the nanoflagellate. Furthermore, SSU rRNA gene of the nanoflagellate exhibited numerous sequence differences compared to other Paraphysomonas species.

The purB gene of Escherichia coli chromosome was cloned and sequenced to determine its transcription regulators. The purB gene for succinyl-adenosine monophosphate (A-AMP) lyase is the second gene of the two-gene transcription-linked promoter which is composed of a pur operator and a DnaA box. The gene exhibited regulatory functions and it is co-transcribed with the ycfC upstream gene for encoding a membrane-associated protein.

Bactericidal/permeability-increasing protein [BPI] Is a cationic antimicrobial protein from neutrophils that specifically binds to the surfaces of Gram-negative bacteria via the lipid A component of lipopolysaccharide. To obtain information about the responses of Salmonella typhimurium to cell-surface damage by BPI, two-dimensional gel electrophoresis and N-terminal microsequencing were used to identify proteins that were induced or repressed following BPI treatment. The majority of the affected proteins are involved in central metabolic processes. Upon addition of BPI, the β-subunit of the F1 portion of Escherichia coli ATP synthase was repressed threefold whereas six proteins were induced up to 11-fold. Three of the latter were identified as lipoamide dehydrogenase, enoyl-acyl carrier protein reductase, and the heatshock protein HtpG. Additionally, a novel protein, BipA, was identified that is induced over sevenfold by BPI; sequence analysis suggests that it belongs to the GTPase superfamily and interacts with ribosomes. A conserved direct-repeat motif is present in the regulatory regions of several BPI-inducible genes. Including the bipA gene. Only one of the BPI-responsive proteins was induced when cells were treated with potymyxin B, which also binds to lipid A. We therefore conclude that BPI and polymyxin B affect different global regulatory networks in S. typhimurium even though they bind with high affinity to the same cell-surface component. [ABSTRACT FROM AUTHOR]

The nature of the experimental error in the initial velocities of an enzyme-catalysed reaction is required if meaningful least-squares regression is to be applied. When a rate equation more complex than that of Michaelis and Menten is to be solved least-squares techniques are the method of choice and so determination of the error structure becomes mandatory. The use of residual analysis and Tukey's T statistics to determine the weights to use are described. This method has the advantage of requiring no additional experimentation over than required for the primary investigation. Using data obtained for Carcinus maenas phosphofructokinase the variance was found to increase with velocity and was approximated by either an empirical power function. var (vi) α v11.8 or by the function, vat (vi)α 0.007 + v21. The latter function is preferred and suggests that the data contains both a constant absolute error and a constant percentage error component. [ABSTRACT FROM AUTHOR]