Morphological colour change: Stage independent, optically induced ommochrome synthesis in larvae of the stick insect,Carausius morosus Br.

Summary The eyes of 4th, 5th, and 6th instar larvae of the stick insect,Carausius morosus, were partially covered with black varnish, and the ommochrome content of treated and untreated animals was determined throughout the instar. In untreated animals kept at 20°C in 16:8 LD the ommochrome content of the integument remains at the level found in newly hatched larvae (10 g/animal), up to the third moult, and increases only slightly (to 30 g) until the adult moult. Darkening the dorsal halves of the eyes does not influence the ommochrome content. Darkening the ventral halves, thus imitating the visual situation of an animal in light on a dark ground, causes after a lag of 3–4 days, a continuous increase of ommochrome content by about 5 g per day. The increase is equal at the beginning and during the second half of the 4th instar, and is also equal in the three instars investigated. Ommine and xanthommatine equally contribute to the increase.     

An evaluation of the global potential of bioenergy production on degraded lands

In this article the global potential of energy crop production on degraded lands was estimated using detailed, spatially explicit data about the area, type and extent of degradation derived from the Global Assessment of Land Degradation Dataset, and by combining this dataset with various spatially explicit data sets. Next, an estimate was made of the possible yield of perennial energy crops on the degraded areas as a function of the type and degree of degradation. Lightly degraded areas were not included, as these areas might be suitable for conventional food production. The total global potential energy production on degraded lands was assessed to be slightly above 150 and 190 EJ yr^?1, for grassy and woody energy crops, respectively. Most of this potential, however, is on areas currently classified as forest, cropland or pastoral land, leaving a potential of around 25 and 32 EJ yr^?1 on other land cover categories. Most of the potential energy crop production on degraded land is located in developing regions. China has a total potential of 30 EJ yr^?1, of which 4 EJ yr^?1 from areas classified as other land. Also USA, Brazil, West Africa, East Africa, Russia and India have substantial potentials of 12–18 EJ yr^?1, with up to 30% of the potential from areas classified as other land.     

Biogas Production from Maize: Current State, Challenges, and Prospects. 1. Methane Yield Potential

Growing interest in converting biomass to renewable energies has led to a considerable expansion of maize cultivation in Germany to provide substrate for anaerobic digestion, producing methane for heat and electricity generation. For decades, maize has been bred for human and livestock nutrition as well as industrial purposes, but not for biomethanization. This review addresses the optimization potential for enhancing maize methane yield, especially open issues pertaining to biogas maize breeding objectives. A great challenge to be faced is the precise quantification of maize-specific methane yield (SMY), i.e., the methane yield per unit biomass. Methodological aspects covered in this review include the impact of the fermentation test procedure as well as of substrate conservation and pretreatment. The contribution of genotypic variation to methane hectare yield (MHY) and SMY are discussed and changes in SMY and MHY during maturation are assessed with respect to harvest timing. The review concludes with a systematic overview of research findings on the relation between SMY and chemical composition, approaches to SMY estimation, and their validation. There is still considerable controversy concerning a biogas maize ideotype; recent research, however, suggests that it differs from the forage maize ideotype, and that a high methane yield can be achieved by different breeding strategies.     

PHB accumulation in Nostoc muscorum under different carbon stress situations

Use of algae for intracellular poly-β-hydroxybutyrate (PHB) accumulation for bioplastic production offers an opportunity in economic efficiency by reduced costs. The cyanobacterium Nostoc muscorum is a PHB accumulator which presents a great potential as raw material supplier because of short generation cycles. Here, we examined a range of experimental conditions including different growth conditions of phosphate-starved cells with the addition of external carbon sources. The highest, absolute PHB accumulation was measured in a phosphate-starved medium with 1% (w/w) glucose and 1% (w/w) acetate. PHB accumulated inside algae cells. After 23 days of growth in phosphate-starved medium, 1 L of culture contained up to 145.1 mg PHB. The highest PHB accumulation based on the cell dry weight was in an experiment with aeration and CO₂ addition. The intracellular level of PHB was up to 21.5% cell dry weight after 8 days.     

Interplay between hydroxylamine,metarhodopsin II and GTP-binding protein in bovine photoreceptor membranes

The decay reactions of metarhodopsin II and the dissociation of the complex between rhodopsin (in the metarhodopsin II state) and the GTP-binding protein (G-protein) (in its inactive, GDP-binding form) have been compared at various concentrations of hydroxylamine. The reactions of the chromophore were measured by absorption changes in the visible range, the complex dissociation by changes in the near-in-frared scattering. An additional monitor of the complex was given by the G-protein-dependent equilibrium between metarhodopsin I and metarhodopsin II. For all measurements, fragments of isolated bovine rod outer segments in suspension were used. In the absence of hydroxylamine, the rhodopsin-G-protein complex dissociated within 20–30 min at room temperature. The presence of hydroxylamine greatly accelerated (e.g., 5-fold at 1 mM NH₂OH) the dissociation. Under all conditions, the free, dissociated G-protein can reassociate to metarhodopsin II produced by subsequent bleaching. Dissociation of the metarhodopsin II-G-protein complex required the decay of photoproducts with a maximal absorbance of 380 nm, but was not affected by the simultaneous presence of metarhodopsin III or metarhodopsin III — like photoproducts with a maximal absorbance between 450 and 470 nm. Despite the acceleration of metarhodopsin II-G-protein dissociation by NH₂OH, metarhodopsin II-G-protein was relatively stabilized as compared to free metarhodopsin II. The ratio of the decay rates of free metarhodopsin II and metarhodopsin III-G-protein was increased as much as 10-fold in the presence of 25 mM NH₂OH. The results indicate a mutual interdependence of retinal, opsin and G-protein.     

Oscillatory penicillin formation in carbon-limited batch fermentations of Penicillium chrysogenum

Circadian oscillations of penicillin productivity with a period of 22±2 h have been observed in carbon-limited batch fermentations of Penicillium chrysogenum. The specific penicillin production rate oscillated with an amplitude of 20 to 100% of its mean value, depending on the growth rate of the active (respiring and producting) biomass. In spite of this, the penicillin concentration increased almost linearly if the optimum growth rate of the active biomass for maximum penicillin productivity was maintained using microprocessor control. This apparently inconsistent behaviour of the fungus is discussed on the basis of chaos theory.