Comparison of quasisteady-state performance of the DEAMOX process under intermittent and continuous feeding and different nitrogen loading rates

The recently developed denitrifying ammonium oxidation (DEAMOX) process combines the anammox reaction with autotrophic denitrifying conditions using sulfide as an electron donor for the production of nitrite from nitrate within an anaerobic biofilm. This paper compares a quasisteady-state performance of this process for treatment of baker's yeast wastewater under intermittent and continuous feeding and increasing nitrogen loading rate (NLR) from 300 till 858 mg N/L/d. The average total nitrogen removal slightly decreased on increasing the NLR: from 86 to 79% (intermittent feeding) and from 87 to 84% (continuous feeding). The better performance under continuous feeding was due to a more complete nitrate removal in the former case whereas the ammonia removal was similar for both feeding regimes under the comparable NLR. A possible explanation can be that, during continuous feeding (simultaneous supply of nitrate and sulfide), there were less mass transfer limitations for sulfide oxidizing denitrifiers presumably located in the outer layer of sludge aggregates. On the contrary, the ammonia oxidisers presumably located inside the aggregates apparently suffered from nitrite mass transfer limitations under both the feedings. The paper further describes some characteristics of the DEAMOX sludge.     

Targeting autophagic regulation of NFkappaB in HTLV-I transformed cells by geldanamycin: implications for therapeutic interventions

The IkappaB kinase (IKK)/NFkappaB signaling pathway plays an essential role in the development and survival of many types of cancers including adult T-cell leukemia (ATL) caused by the human T-cell leukemia virus type I (HTLV-I) infection. Accordingly, targeting NFkappaB provides an attractive strategy for cancer therapy. We recently found that specific inhibition of Hsp90 by geldanamycin (GA) results in autophagic degradation of IKK and NFkappaB-inducing kinase (NIK), an upstream kinase of IKK, and inactivation of NFkappaB in various cell lines. Here, we further report that GA inhibition of Hsp90 also led to IKK autophagic degradation and NFkappaB inhibition in both HTLV-transformed T cells and ATL-derived cell lines. Importantly, GA treatment led to efficient apoptosis of these malignant cells, whereas inhibition of autophagic degradation of IKK significantly ameliorated the cytotoxic effect of GA. These findings thus not only provide mechanistic insights into the tumor suppression function of autophagy and the anti-tumor activity of GA, but also suggest an immediate therapeutic strategy for ATL and other diseases associated with NFkappaB activation by targeting autophagic degradation of the central NFkappaB activating kinases.     

Identification of three phases in Onconase refolding

Onconase is an extremely stable member of the RNase A superfamily. The increase in the thermodynamic stability by 20 kJ x mol(-1) in comparison to RNase A was expected to result in altered folding behavior. Despite the lack of cis-Pro residues in native Onconase, refolding at low concentrations of guanidine hydrochloride was complex and showed three kinetic phases (fast, medium, and slow), with rate constants differing by a factor of about 10 each. None of the phases could be accelerated by peptidyl-prolyl cis-trans isomerases, pointing to the absence of kinetic phases that are limited by Pro isomerization. The detailed analysis by various probes indicates that the burial of the N-terminal Trp3, which is associated with the restoration of the active site, occurs in the slow phase, i.e. in the last step of refolding. Evidently, in contrast to the folding of RNase A, there is no catalytically active native-like intermediate in the folding of Onconase.     

Proteomic analysis in the model organism Daphnia has the potential to unravel molecular pathways involved in phenotypic changes in response to changing environmental conditions

Hydrobiologia - The crustacean genus Daphnia holds a key position in aquatic ecosystems rendering it an important model organism in environmental research. Its enormous sensitivity to environmental...     

‘Birth defects’ of photosystem II make it highly susceptible to photodamage during chloroplast biogenesis

High solar flux is known to diminish photosynthetic growth rates, reducing biomass productivity and lowering disease tolerance. Photosystem II (PSII) of plants is susceptible to photodamage (also known as photoinactivation) in strong light, resulting in severe loss of water oxidation capacity and destruction of the water‐oxidizing complex (WOC). The repair of damaged PSIIs comes at a high energy cost and requires de novo biosynthesis of damaged PSII subunits, reassembly of the WOC inorganic cofactors and membrane remodeling. Employing membrane‐inlet mass spectrometry and O₂‐polarography under flashing light conditions, we demonstrate that newly synthesized PSII complexes are far more susceptible to photodamage than are mature PSII complexes. We examined these ‘PSII birth defects’ in barley seedlings and plastids (etiochloroplasts and chloroplasts) isolated at various times during de‐etiolation as chloroplast development begins and matures in synchronization with thylakoid membrane biogenesis and grana membrane formation. We show that the degree of PSII photodamage decreases simultaneously with biogenesis of the PSII turnover efficiency measured by O₂‐polarography, and with grana membrane stacking, as determined by electron microscopy. Our data from fluorescence, Q_B‐inhibitor binding, and thermoluminescence studies indicate that the decline of the high‐light susceptibility of PSII to photodamage is coincident with appearance of electron transfer capability Q_A^? → Q_B during de‐etiolation. This rate depends in turn on the downstream clearing of electrons upon buildup of the complete linear electron transfer chain and the formation of stacked grana membranes capable of longer‐range energy transfer.     

Steroid accumulation in song nuclei of a sexually dimorphic duetting bird,the rufous and white wren

This study tested the hypothesis that the relative proportion of neurons that are hormone sensitive in avian song control nuclei is related to the basic motor ability to sing, whereas the absolute number of such neurons is related to the complexity of song behavior. Either [³H]testosterone (T) or estradiol (E₂) was injected into male and female rufous and white wrens (Thryothorus rufalbus), a tropical species in which females sing duets with males but have smaller song repertoires than males. Autoradiographic analysis indicated that there were no sex differences in the proportions of T or E₂ target cells in two song nuclei: the high vocal center (HVC) and the lateral portion of the magnocellular nucleus of the anterior neostriatum (IMAN). The density of labeled cells per unit volume of tissue did not differ between the sexes in either song nucleus. Males have larger song nuclei, however, which is consistent with their more complex song behavior, and therefore have a greater total number of hormone-sensitive neurons in these regions than do females. Comparison of these results with measures of hormone accumulation in zebra finches, canaries, and bay wrens supports the hypothesis presented. © 1996 John Wiley & Sons, Inc.