Specificity of P2 primary alkylsulphohydrolase induction in the detergent-degrading bacterium Pseudomonas C12B. Effects of alkanesulphonates, alkyl sulphates and other related compounds.

Primary alkanesulphonates were shown to serve as non-metabolizable (gratuitous) inducers of the P2 primary alkylsulphohydrolase enzyme in resting cell suspensions of Pseudomonas C12B. The effects of increasing concentrations of inducer on the production of enzyme were complex and suggestive of a multiphasic phenomenon. However, it was possible to determine Kinducer constants (analogous to Km or Ki) for alkanesulphonates of chain length from C7 to c12. these decreased with increasing chain length in a manner characteristic of an homologous series. Primary alkyl sulphates also served as good inducers of alkylsulphohydrolase, but valid kinetic values could not be obtained because these esters are good substrates for the enzyme and are therefore appreciably hydrolysed during the induction period. Small amounts of enzyme were also produced when cyprinol sulphate, dodecyltriethoxy sulphate C12H23-[O-CH2-CH2]3-O-SO3-Na+), Crag herbicide and some secondary alkyl sulphates were tested as inducers.     

Biogenesis of mitochondria. 52

Summary The characteristics of recombination of several petite (rho ^-) mutants of S. cerevisiae that retain the -influenced region of the mitochondrial genome, identified by the markers cap1-r, ery1-r and tsr1, are described. The petites were derived from an ^– grande (rho ⁺) strain and those petites which retain all three markers show recombination properties similar to those of the ^- parental strain. However, other rho ^- mutants that retain the cap1 and ery1 loci but have lost the tsr1 locus, which is located between cap1 and ery1, show markedly different properties of mitochondrial transmission and recombination, consistent with the presence of ⁺ alleles. The association of an internal deletion between the cap1 and ery1 loci with a change in phenotype provides additional evidence for the location of between these two loci.Although the petites deleted for the tsr1 locus exhibited the recombination properties of ⁺ strains, it was not possible to transmit this characteristic to rho ⁺ recombinant cells. Experiments on the kinetics of elimination by ethidium bromide of the cap1 and eryl markers from the petites and measurements of the buoyant densities of their mtDNA species did not indicate major changes (such as selective sequence repetition) in the sequences of the mtDNAs. The possible nature of the changes in the mtDNAs of these petites is discussed in light of recent studies on the physical nature of the alleles.     

Sodium binding in Halobacterium halobium measured by the nuclear magnetic resonance technique

Relaxation time measurements T₁ and T₂ of sodium in Halobacterium halobium pellets were carried out at two frequencies. From those measurements, combined with intensity measurements of the sodium in the system, estimation of the properties of the sodium ions in the system was carried out. It is suggested that three types of sodium ions are present in the bacterial pellet. (A) The extracellular sodium with properties of free solution and (B) sodium which is in the pericellular volume between the cell wall and the cell membrane. There is an exchange between type A and type B sodium. The type B sodium has (e²qQ)/h = 3.7 · 10⁷ rad/s, τ_cB = 5.2 · 10⁻⁶ s and τ_B = 1 · 10⁻³ s. The sodium of type C is bound inside the cell and undetected. It's concentration inside the cell is assumed to be 1.9 M.     

Retinoblastoma,gross internal malformations,and deletion 13q14→q31

Summary A male patient with an interstitial deletion 13q14q31 is described. Our necropsy findings included a left retinoblastoma and several gross internal malformations. In this paper we reaffirm that band 13q14 is involved in cases of retinoblastoma and we propose, after studying accompanying cases of total or partial long arm trisomies 13, that the loss of specific 13q bands, from 13q14 to 13q31 is responsible for the congenital defects we are describing.     

Augmented therapeutic results elicited by splenectomy in combined modality treatment of spontaneous murine breast cancer

Summary Because it had been reported that splenectomy produces a tumor-inhibitory effect in several transplantable tumor systems when the surgery is performed before tumor challenge, we attempted to examine this putative immunological manipulation in a therapeutic situation.A spontaneous, autochthonous, murine breast tumor system was utilized in the present studies, and treatment was initiated in animals bearing large tumors (averaging 0.5 g). To amplify any immunological benefit ensuing from splenectomy, the tumor burden in the host was reduced by ancillary treatment with enucleative tumor surgery or with enucleative tumor surgery plus cytoreductive combination chemotherapy.Splenectomy performed in conjunction with enucleative tumor surgery was associated with an increment of cure in each of four separate experiments in comparison to treatment with enucleative tumor surgery alone. In four of five experiments utilizing different combinations or schedules of chemotherapeutic agents following enucleative tumor surgery, the addition of splenectomy resulted in a decrease in the rate of tumor recurrence as well as an increment in the cure rate. In the fifth experiment, splenectomy resulted in a decrease in the rate of tumor recurrence, but did not effect the ultimate cure rate.Although the nature of the immunological changes resulting from splenectomy are incompletely defined at present, these results provide encouragement in the search for immunological treatments for solid tumors.This work was supported in part by Contract No. N01-CM-73703 and Grant IR01CA-14768-01A1, both from the National Cancer Institute, National Institutes of Health, Department of Health, Education and Welfare, USA, and in part by a grant from the Chemotherapy Foundation of New York, Inc.     

Biogenesis of mitochondria 49 identification and mapping of a new mitochondrial locus (tsr1) which maps within polar region of yeast mitochondrial genome.

Summary An enrichment procedure which facilitates the isolation of conditional respiratory-deficient mutants of Saccharomyces cerevisiae is reported. Detailed genetic analysis of one mutant which exhibits a respiratory deficient phenotype at low temperature (18°C) is also presented. The phenotype is due to a single lesion at a new locus, tsr1, located on the mitochondrial DNA. By analysis of locus retention patterns in a set of physically characterized petite strains, the tsr1 mutation has been mapped within the segment 0–5 map units on the physical map of the yeast mitochondrial genome. This segment of the mitochondrial DNA also contains the cap1 and ery1 loci and the cistron for the mitochondrial 21S rRNA. Studies of the frequencies of co-retention of markers in petite populations, and of the frequencies of recombination of markers in non-polar crosses (⁺ × ⁺), demonstrate linkage of the tsr1 locus to both the cap1 and ery1 loci. The degree of linkage indicates that tsr1 is closer to the ery1 locus. Comparison of pairwise recombination frequencies for these three markers indicate the order cap1-tsr1-ery1. The tsr1 locus lies within the segment of the mitochondrial genome which is influenced by the polarity locus , and analysis of transmission and recombination frequencies and polarities in a polar (⁺ × ^-) cross show that the behaviour of the tsr1 locus is similar to that of ery1. However striking features of this cross are that the recombination frequency between tsr1 and ery1 is comparable to that observed in non-polar crosses, and that the polarity for recombination between tsr1 and cap1 or ery1 is extremely low.     

The temperature-dependence of the loss of latency of lysosomal enzymes

1. When Triton-filled lysosomes from rat liver are incubated for up to 50min at 37 degrees C, pH7.4, in 0.25m-sucrose, no loss of latency of N-acetyl-beta-glucosaminidase or p-nitrophenyl phosphatase occurs unless the incubated lysosomes are cooled to approx. 15 degrees C. 2. It is suggested that a phase change takes place in the incubated lysosomal membranes on cooling; it starts at approx. 15 degrees C and probably is not complete at 0 degrees C. 3. Incubation of the lysosomes causes an increased potential for loss of latency of the lysosomal enzymes. This potential is not fully expressed at elevated temperature (e.g. 37 degrees C), but is expressed on cooling. 4. The increase at elevated temperature in potential for loss of latency exhibits biphasic kinetics, with an initial rapid phase followed by a slower phase, which is linear with respect to time. The extra loss of latency resulting from the rapid phase in proportional to the temperature of the incubation. 5. Arrhenius plots of the increase is potential for loss of latency during the slow phase for N-acetyl-beta-glucosaminidase and p-nitrophenyl phosphatase exhibit marked deviations from linearity beginning at approx. 15 degrees C. This suggests that the increase in potential for loss of latency is affected by a phase change that occurs around this temperature. 6. Activation energies for the increase in potential for loss of latency at and above 22 degrees C are 53.1+/-5.4kJ/mol (12.7+/-1.3kcal/mol) for N-acetyl-beta-glucosaminidase and 45.2+/-7.5kJ/mol (10.8+/-1.8kcal/mol) for p-nitrophenyl phosphatase. It is postulated that these energies reflect enzymic action, the products of which cause loss of latency to occur on cooling.     

Nonidentity of chromogranin a and dopamine β-monooxygenase

Dopamine β-monooxygenase (EC 1.14.17.1) and chromogranin A from bovine adrenal chromaffin granules were purified by established procedures and examined for evidence of structural identity. The minimum molecular weights were determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and found to be 74,000 and 35,000, respectively. Amino acid analyses of the two proteins are distinct. Dopamine β-monooxygenase does not possess a free amino terminus, whereas chromogranin A has a leucine amino terminus. Analysis in the protein sequencer showed that chromogranin A contains only a single degradable polypeptide chain. Radioactive S-carboxymethyl derivatives of the two proteins were prepared to compare the soluble peptides after thermolysin digestion. These thermolytic peptides were isolated from columns of Dowex 50-X8 resin and both the peptide and radioactive traces revealed no evidence for similarity of the two proteins, either in toto or in part. Thus, although dopamine β-monooxygenase and chromogranin A may sometimes be copurified, they are distinct entities.