Sulfide oxidation by spheroplasts of Thiobacillus ferrooxidans.

Thiobacillus ferrooxidans is an acidophilic organism important to metal leaching of low-grade ores. The aforementioned importance is related to the ability of the bacterium to oxidize reduced iron and sulfur, principally found in nature as pyrite (FeS2). The present study dealt with sulfide oxidation at low pH values and the involvement of the cell envelope in the process of the inorganic oxidations. Sulfide oxidation was noted in spheroplasts of T. ferrooxidans prepared by enzymatic and chemical treatments and partially purified by differential centrifugation. No enzyme activities were noted in membrane fractions containing enrichments of lipopolysaccharide symbolic of outer membrane material or in membrane vesicles containing (or associated with) higher levels of proteins. Results to date indicate that in an acid milieu the envelope structure containing both the outer membrane and the intact inner cytoplasmic membrane is required for sulfide oxidation.     

The synthesis,characterization, and preliminary biological evaluation of 1-β-D-arabinofuranosylcytosine-5′-diphosphate-L-1,2-dipalmitin

Recently, 1-β-$\text{D}$-arabinofuranosylcytosine-5′-diphosphate-$\text{DL}$-1,2-dipalmitin (VIa) was reported to inhibit the growth of L51784 cells in mice and of human colon carcinoma HCT-15 cells, also in mice. This paper describes the synthesis of a single diastereomer by conversion of 1-β-$\text{D}$-arabinofuranosylcytosine 5′-monophosphate (II) to the nucleoside 5′-phosphomorpholidate (III), followed by reaction with $\text{L}$-α-dipalmitoylphosphatidic acid (IV) to give 1-β-$\text{D}$-arabinofuranosylcytosine-5′-diphosphate-$\text{L}$-1,2-dipalmitin (V) in good yield. The separation of the product is described and its characterization by chromatography, elemental analysis, and spectroscopic methods. The lipophilic nature of V renders it insoluble in aqueous media and a method of sample preparation utilizing sonication techniques is described which provides a clear solution suitable for biological evaluation. In addition, the ability of V to inhibit the $\text{in}\text{vitro}$ growth of L1210 cells and of mouse myeloma MPC 11 cells is desscribed and compared with 1-β-$\text{D}$-arabinofuranosylcytosine (I) and other lipophilic prodrugs of I.     

Light-dependent development of thermoluminescence, delayed emission and fluorescence variation in dark-grown spruce leaves

Thermoluminescence profiles of spruce leaves grown under various light or dark conditions were measured after excitation at a low temperature (−70 to −20 °C) by 1-min illumination with red light, and the following results were obtained. Mature spruce leaves showed five thermoluminescence bands at −30, −5, +20, +40 (or +35) and +70 °C (denoted as Z_v, A, B₁, B₂ and C bands, respectively), but dark-grown spruce leaves with a similar chlorophyll content showed only two bands, at −30 and +70 °C (the Z_v and C bands) and were devoid of the three other bands (the A, B₁ and B₂ bands). On exposure of the dark-grown leaves to continuous red light, the A, B₁ and B₂ bands were rapidly developed, and the development was accompanied by enhancement of delayed emission, fluorescence variation and the Hill activity (photoreduction of 2,6-dichlorophenolindophenol with water as electron donor). It was demonstrated that the dark-grown spruce leaves are devoid of the water-splitting system in Photosystem II, and that the latent water-splitting activity is rapidly photoactivated by exposure of the leaves to continuous red light. These results on the gymnosperm spruce leaves, in which greening proceeds in complete darkness, being independent of the development of the water-splitting system in light, were discussed in relation to previous observations on angiosperm leaves, in which both greening and the activity generation proceed in the light.     

Multiple-flash development of thermoluminescence bands in dark-grown spruce leaves

Spruce leaves greened in darkness were devoid of three of the five thermoluminescence bands found for mature leaves. These bands were developed rapidly by exposure of the dark-grown leaves to continuous light. The development of these bands was studied by illumination with repetitive flashes at varied intervals. Flashes at intervals of 1 s were the most effective in inducing these bands. Those at shorter or longer intervals were less effective. It was deduced from these data that the development of these bands is a multiquantum process which involves at least two photo-events with a dark reaction between them.     

Adsorption of Vibrio parahaemolyticus onto Chitin and Copepods

Vibrio parahaemolyticus was observed to adsorb onto chitin particles and copepods. The efficiency of adsorption was found to be dependent on pH and on the concentration of NaC1 and other ions found in seawater. Highest efficiency was observed in water samples collected from Chesapeake Bay and lowest in water from the open sea. V. parahaemolyticus was found to adborb onto chitin with the highest efficiency of the several bacterial strains tested. Escherichia coli and Pseudomonas fluorescens did not adsorb onto chitin. The adsorption effect is considered to be one of the major factors determining the distribution of this species and affecting the annual cycle of V. parahaemolyticus in the estuarine system.     

Oxygen evolution in dark-developed spruce chloroplasts

Chloroplasts isolated from dark-grown seedlings of Picea abiesshowed activities of DCIP and Fecy photoreductions widiout additionof an electron donor to PS-II. In addition to this, when light-inducedoxygen evolution was measured with an oxygen electrode, a significantamount of oxygen was found. These results indicate that thephotoreductions are coupled to the oxygen-evolving reaction.Furthermore, thylakoid membranes were functional in the protonuptake and the 515-nm absorbance change as parameters of theirphysicochemical functions. Electron microscopy showed that thylakoidswere well-developed with prolamellar bodies and partially stackedto from grana. We conclude that oxygen-evolving ability and the physicochemicalfunction of thylakoid membranes develop in chloroplasts of dark-grownspruce seedlings. (Received September 21, 1974; )