Continuous ethanol fermentation of cheese whey powder solution: effects of hydraulic residence time

Continuous ethanol fermentation of cheese whey powder solution was realized using pure culture of Kluyveromyces marxianus (DSMZ 7239) at hydraulic residence times (HRT) between 12.5 and 60 h. Sugar utilization, ethanol and biomass formation were investigated as functions of HRT. Effluent sugar concentration decreased, but percent sugar utilization, ethanol and biomass concentrations increased with HRT. Ethanol productivity was maximum (0.745 gE l⁻¹h⁻¹) at an HRT of 43.2 h where the biomass productivity was almost minimum (0.18 gX l⁻¹ h⁻¹). The ethanol yield coefficient was almost constant at 0.4 gE g⁻¹S up to HRT of 43.2 h and the growth yield coefficient was minimum at HRT of 43.2 h. Kinetic models were developed and the constants were determined by using the experimental data.     

Rhodobacter capsulatus magnesium chelatase subunit BchH contains an oxygen sensitive iron–sulfur cluster

Magnesium chelatase is the first unique enzyme of the bacteriochlorophyll biosynthetic pathway. It consists of three subunits (BchI, BchD, and BchH). Amino acid sequence analysis of the Rhodobacter capsulatus BchH revealed a novel cysteine motif (³⁹³CX₂CX₃CX₁₄C) that was found in only six other proteobacteria (CX₂CX₃CX_11–14C). The cysteine motif is likely to coordinate an unprecedented [Fe–S] cluster. Purified BchH demonstrated absorbance in the 460 nm region. This absorbance was abolished in BchH proteins with alanine substitutions at positions Cys396 and Cys414. These modified proteins were also EPR silent. In contrast, wild type BchH protein in the reduced state showed EPR signals resembling those of a [4Fe–4S] cluster with rhombic symmetry and g values at 1.90, 1.93, and 2.09, superimposed with a [3Fe–4S] cluster centered at g = 2.02. The [3Fe–4S] signal was observed independently of the [4Fe–4S] signal under oxidizing conditions. Mg-chelatase activity assays showed that the cluster is not catalytic. We suggest that the [4Fe–4S] and [3Fe–4S] signals originate from a single coordination site on the monomeric BchH protein and that the [4Fe–4S] cluster is sensitive to oxidation. It is speculated that the cluster participates in the switching between aerobic and anaerobic life of the proteobacteria.     

Synthesis and characterization of novel substituted thiophene derivatives and discovery of their carbonic anhydrase and acetylcholinesterase inhibition effects

Novel substituted thiophene derivatives ( 1, 2a‐e, 3, and 4 ) were synthesized and their structures were characterized by infrared radiation, nuclear magnetic resonance, and mass analysis. These novel substituted thiophene derivatives were effective inhibitor compounds of the carbonic anhydrase I and II isozymes (hCA I and II), and acetylcholinesterase (AChE) enzyme with K _i values in the range of 447.28 to 1004.65 nM for hCA I, 309.44 to 935.93 nM for hCA II, and 0.28 to 4.01 nM for AChE, respectively. Novel substituted thiophene derivatives can be good candidate drugs for the treatment of some diseases like neurological disorders, epilepsy, glaucoma, gastric and duodenal ulcers, mountain sickness, or osteoporosis as carbonic anhydrase isozymes inhibitors, and for the treatment of Alzheimer’s and Parkinson’s diseases as acetylcholinesterase inhibitors.     

Spectroscopic and Structural Characterization,Enzyme Inhibitions,and Antioxidant Effects of New Ru(II) and Ni(II) Complexes of Schiff Base

The new complex compounds [RuLCl(p‐cymene)] ? 3H₂O and [NiL₂(H₂O)₂] ? 3H₂O (L: 1‐{4‐[(2‐hydroxy‐3‐methoxybenzylidene)amino]phenyl}ethanone) were prepared and characterized using FT‐IR, ¹H‐ and ¹³C‐NMR, mass spectroscopy, TGA, elemental analysis, X‐ray powder diffraction and magnetic moment techniques. Octahedral geometry for new Ni(II) and Ru(II) complexes was proposed. Thermal decomposition confirmed the existence of lattice and coordinated water molecule in the complexes. To determine the antioxidant properties of Schiff base ligand and its Ni(II), Ru(II) metal complexes, FRAP, CUPRAC, ABTS and DPPH methods of antioxidant assays were used. Moreover, enzyme inhibition of complexes was evaluated against carbonic anhydrase I and II isoenzymes (CA I and CA II) and acetylcholinesterase (AChE). For CA I and CA II, the best inhibition enzymes, was the Ni(II) complex with 62.98±18.41, 86.17±23.62 Ki values, whereas this inhibition effect showed ligand with 24.53±2.66 Ki value for the AChE enzyme.     

Functional characterization of monomeric photosystem II core preparations from Thermosynechococcus elongatus with or without the Psb27 protein

Two monomeric fractions of photosystem II (PS II) core pacticles from the thermophilic cyanobacterium Thermosynechococcus elongatus have been investigated using flash-induced variable fluorescence kinetics and EPR spectroscopy. One fraction was highly active in oxygen evolution and contained the extrinsic protein subunits PsbO, PsbU, and PsbV. The other monomeric fraction lacked oxygen evolving activity as well as the three extrinsic subunits, but the luminally located, extrinsic Psb27 lipoprotein was present. In the monomeric fraction with bound Psb27, flash-induced variable fluorescence showed an absence of oxidizable Mn on the donor side of PS II and impaired forward electron transfer from the primary quinone acceptor, QA. These results were confirmed with EPR spectroscopy by the absence of the "split S1" interaction signal from YZ* and the CaMn4 cluster and by the absence of the S2-state multiline signal. A different protein composition on the donor side of PS II monomers with Psb27 was also supported by the lack of an EPR signal from cytochrome c550 (in the PsbV subunit). In addition, we did not observe any oxidation of cytochrome b559 at low temperature in this fraction. The presence of Psb27 and the absence of the CaMn4 cluster did not affect the protein matrix around YD or the acceptor side quinones as can be judged from the appearance of the corresponding EPR signals. The diminished electron transport capabilities on both the donor and the acceptor side of PS II when Psb27 is present give further indications that this PS II complex is involved in the earlier steps of the PS II repair cycle.     

Knowledge, Learning and the Evolution of Conservation Practice for Social-Ecological System Resilience

There are two broadly conceptualized ways in which conservation knowledge may evolve: the depletion crisis model and the ecological understanding model. The first one argues that developing conservation thought and practice depends on learning that resources are depletable. Such learning typically follows a resource crisis. The second mechanism emphasizes the development of conservation practices following the incremental elaboration of environmental knowledge by a group of people. These mechanisms may work together. Following a perturbation, a society can self-organize, learn and adapt. The self-organizing process, facilitated by knowledge development and learning, has the potential to increase the resilience (capability to absorb disturbance and reorganize while undergoing change) of resource use systems. Hence, conservation knowledge can develop through a combination of long-term ecological understanding and learning from crises and mistakes. It has survival value, as it increases the resilience of integrated social--ecological systems to deal with change in ways that continue to sustain both peoples and their environments.     

Effect of 3-(1<Emphasis Type="Italic">H</Emphasis>-Pyrrol-2-yl)-1<Emphasis Type="Italic">H</Emphasis>-Indazole on the Antioxidant Status of Rats

The influence of injection periods of 3-(1H-pyrrol-2-yl)-1H-indazole regarding vitamins A, E, C, selenium (Se), malondialdehyde (MDA) levels, and glutathione peroxidase (GSH-Px) activity in rats has been investigated. The substance was given by subcutaneous injection at 20 mg/kg every other day for a total of 15 injections. At the end of the treatment, Se levels in serum were determined by fluorimetry, and those of vitamins A, E, C, and malondialdehyde in serum, liver, and kidney were determined by high-performance liquid chromatography. GSH-Px activities in erythrocytes were determined spectrophotometrically. Vitamins A, E, C, and Se levels were generally lower than in the controls, while GSH-Px activity at the third injection period was maximally increased, with the activities after the other injection periods being higher than in the control group. In addition, vitamins A, E, and C levels were generally lower than the control groups, while serum, liver, and kidney MDA levels gradually increased depending on injection periods. On the other hand, GSH-Px activity was higher than in the control group. Thus, the results show that while vitamins A, E, C, and Se levels decreased, MDA levels and GSH-Px activities increased after administration of 3-(1H-pyrrol-2-yl)-1H-indazole to the rats. These findings might be related to the increased amount of free radicals caused by 3-(1H-pyrrol-2-yl)-1H-indazole injection.     

Comparison of the selenium level with GSH-Px activity in the liver of mice treated with 7,12 DMBA

In this study, the relationship between selenium (Se) and glutathione peroxidase (GSHPx) levels was investigated in 7,12-dimethylbenz(a)anthracene (7,12-DMBA)-treated mouse liver. The potential mammary carcinogen 7,12-DMBA, was injected intraperitoneally (20 mg kg(-1) day(-1)) into 10-12 month old female mice. After 21 days of application the mice were sacrificed and GSHPx and Se levels of liver homogenates were measured. Se and GSHPx levels in 7,12-DMBA-treated mice were significantly lower than those of controls (p < 0.05). The control group exhibited 0.9 +/- 0.066 U mg(-1) protein and 0.86 +/- 0.058 p.p.m. levels of GSHPx and Se respectively. The 7,12-DMBA-treated group had significantly (p < 0.05) decreased GSHPx and Se levels (0.42 +/- 0.062 U mg(-1) protein and 0.69 +/- 0.034 p.p.m. respectively). The results show a direct relationship between Se and GSHPx activity and a negative correlation between antioxidant capacity and existence of a carcinogen in metabolism.     

Indigenous Knowledge of Ecological Variability and Commons Management: A Case Study on Berry Harvesting from Northern Canada

Common property arrangements govern the subsistence harvest of berries in the Gwich’in region of the Northwest Territories, Canada. Some of these arrangements, including rules for resource access, sharing information and harvest sharing, enable the Gwich’in to deal with ecological variability. The rules change in response to year-to-year variations in the abundance and distribution of the species, spatially and temporally across the region. This paper illustrates the interrelationships between ecosystem dynamics and local institutions, a neglected area of commons research.An erratum to this article can be found at