We have identified the function of the 'extra' polypeptides involved in phycobilisome assembly in Nostoc sp. These phycobilisomes, as those of other cyanobacteria, are composed of an allophycocyanin core, phycoerythrinand phycocyanin-containing rods, and five additional polypeptides of 95, 34.5, 34, 32, and 29 kilodaltons. The 95 kilodalton polypeptide anchors the phycobilisome to the thylakoid...

presence and activity of denitrifiers. These factors have The effect of NO3--N diffusion on the order and rate of debeen studied bv several workers, for example, Bremner and nitrification reaction was studied in IS soils from various locations in Shaw (1958a, 1958b), Nommik (1956), Patrick (1960), the U.S. The soils were amended with 0.5% rice straw and incubated Broadbent and Clark (1965), and...

In this paper, we model the pair-wise similarities of a set of documents as a weighted network with a single cutoff parameter. Such a network can be thought of an ensemble of unweighted graphs, each consisting of edges with weights greater than the cutoff value. We look at this network ensemble as a complex system with a temperature parameter, and refer to it as a Latent Network. Our experiment...

The stability of postlogarithmic mRNA has been assessed in Bacillus subtilis during sporulation time periods. The appearance of refractile bodies, alkaline phosphatase synthesis, and total protein synthesis is controlled by mRNA which has an estimated half-life of less than 10 min. Inhibition of RNA synthesis at various times by rifampin addition or temperature shift with a temperature-sensitiv...

We have devised a new method that permits the investigation of exogenous secretory vesicle function using frog oocytes and bovine chrornaffin granules, the secretory vesicles from adrenal chromaffin cells. Highly purified chrornaffin granule membranes were injected into Xenopus laevis oocytes . Exocytosis was detected by the appearance of dopamineß-hydroxylase of the chrornaffin granule membran...

Some additional negative ion reactions of possible D-region importance have been measured in the ESSA flowing afterglow system at 300°K. It has been found that NO,does not react with atomic oxygen or atomic nitrogen with a rate constant as large as lo-” cm*/sec. The electron affinity of NO, is found to be greater than that of NOZ by more than 0.9 eV. It is pointed out that conversion of 02to Op...

Development of the neuromuscular junction on differentiating muscle was investigated in the regenerating limb of the newt Triturus . Motor end-plate formation begins when vesiclefilled axon terminations approach differentiating muscle cells that have reached the stage of a multinucleate cell containing myofibrils . Slight ridges or elevations occur on the muscle surface, and there is an increas...

The ureides, allantoin and allantoic acid, represented major fractions of the soluble nitrogen pool of nodulated plants of cowpea ( Vigna unuiulata [L.] Walp. cv. Caloona) throughout vegetative and reproductive growth. Stem and petioles were the principal sites of ureide accumulation, especialy in early fruiting. Labeling studies using 14C02 and 15N2 and incubation periods of 25 to 245 minutes ...

Additional Index Words: rate constant, zero-order reaction, firstorder reaction, submerged soil, available carbon. A theoretical analysis of denitrification occurring in submerged soil in a test tube, when assumed to be a zero-order reaction with available ———————————————————— organic carbon nonlimiting, appears to be a first-order reaction if the __ , , , , c effects of diffusion are neglected...

Nitrate uptake has been studied in nitrogen-deficient cells of the marine diatom Skektowema costatum. When these cells are incubated in the presence of nitrate, this ion is quickly taken up from the medium, and nitrite is excreted by the cells. Nitrite is excreted following classical saturation kineffcs, its rate being independent of nitrate concentration in the incubation medium for nitrate co...