Investigating Physical and Chemical Interaction of Aspergillus terreus Spores for Changes in Morphology and Physiology

It has been widely reported that in filamentous fungi, spore inoculum size affects culture morphology and secondary metabolite production. The reasons for this, however, have not been investigated thus far. There are two possible explanations as to why spore inoculum size affects fungal morphology, growth and productivity. Firstly, a quorum sensing phenomenon (QS). In this case, after population densities reach a certain threshold, signalling chemicals secreted into the environment effect expression of specific genes leading to a range of physiological responses. Secondly, due to physical spore-to-spore contact, communication may develop that could trigger a physical response, altering morphology and productivity. To explore these hypotheses, research was split into two parts: the first “supplementation”, the addition of known quorum sensing molecules butyrolactone I, tyrosol and farnesol, alongside other chemicals expressed in literature as having potential effects on the physiology and morphology of a microbial culture. Furthermore, supplements from Aspergillus terreus MUCL 38669 obtained from I) spore supernatant, II) concentrated spore supernatant via freeze drying (FDSS) and III) high spore culture supernatants from 72-hour liquid cultures, were added to various concentrations of A. terreus spore inocula. The second part investigated effects of physical contact between spores by increasing spore interactions through sonication of spore suspensions and also, altering the physical space in which spores are confined to during growth, thereby forcing spore to spore contact. Investigations showed behaviours similar to cultures affected by QS process. These included morphological changes and increased productivities. Additions of 0.01M farnesol to (low) spore inoculum concentrations of 1x103 spores/mL altered culture morphology to that seen of cultures of 1x107 spores/mL (high), lovastatin production also increased by 1208%. Similarly, the morphology of low spore cultures supplemented with FDSS were that of high spore cultures and lovastatin production increased by 67%. Sonication had no effect on cultures, however, confinement evoked changes in morphological characteristics and germination times of the culture

Correlations in nuclear energy recurrence relations

The excitation energies of states belonging to the ground state bands of heavy even-even nuclei are analysed using recurrence relations. Excellent agreement with experimental data at the 10 keV level is obtained by taking into account strong correlations which emerge in the analysis. This implies that the excitation energies can be written as a polynomial of maximum degree four in the angular momentum.Comment: 4 pages, 1 figure, 1 table, 9 reference

‘The tempter or the tempted, who sins most?’: Love and Lust in Measure for Measure and The Law Against Lovers

On 8 December 1660, following a long history of the prohibition of actresses in England, a feminine presence took to the London stage and altered it..

The effects of localized damping on structural response

The effect of localized structural damping on the excitability of higher order normal modes of the large space telescope was investigated. A preprocessor computer program was developed to incorporate Voigt structural joint damping models in a NASTRAN finite-element dynamic model. A postprocessor computer program was developed to select critical modes for low-frequency attitude control problems and for higher frequency fine-stabilization problems. The mode selection is accomplished by ranking the flexible modes based on coefficients for rate gyro, position gyro, and optical sensors, and on image-plane motions due to sinusoidal or random power spectral density force and torque inputs

Current and Shot Noise Measurements in a Carbon Nanotube-Based Spin Diode

Low-temperature measurements of asymmetric carbon nanotube (CNT) quantum dots are reported. The CNTs are end-contacted with one ferromagnetic and one normal-metal electrode. The measurements show a spin-dependent rectification of the current caused by the asymmetry of the device. This rectification occurs for gate voltages for which the normal-metal lead is resonant with a level of the quantum dot. At the gate voltages at which the current is at the maximum current, a significant decrease in the current shot noise is observed