Search

Mixotrophy, the concurrent use of inorganic and organic carbon in the presence of light for microalgal growth, holds ecological and industrial significance. However, it is poorly explored in diatoms, especially in ecologically relevant species like Skeletonema marinoi. This study strategically employed mixotrophic metabolism to optimize the growth of a strain of Skeletonema marinoi (Sm142), which was found potentially important for biomass production on the west coast of Sweden in winter conditions. The aim of this study was to discern the most effective organic carbon sources by closely monitoring microalgal growth through the assessment of optical density, chlorophyll a fluorescence, and biomass concentration. The impact of various carbon sources on the physiology of Sm142 was investigated using photosynthetic and respiratory parameters. The findings revealed that glycerol exhibited the highest potential for enhancing the biomass concentration of Sm142 in a multi‐cultivator under the specified experimental conditions, thanks to the increase in respiration activity. Furthermore, the stimulatory effect of glycerol was confirmed at a larger scale using environmental photobioreactors simulating the winter conditions on the west coast of Sweden; it was found comparable to the stimulation by CO2‐enriched air versus normal air. These results were the first evidence of the ability of Skeletonema marinoi to perform mixotrophic metabolism during the winter and could explain the ecological success of this diatom on the Swedish west coast. These findings also highlight the importance of both organic and inorganic carbon sources for enhancing biomass productivity in harsh winter conditions. [ABSTRACT FROM AUTHOR]

Micellar electrokinetic chromatography with electrochemical detection has been used to quantify biogenic amines in microdissected Drosophila melanogaster brains and brain regions. The effects of pigment from the relatively large fly eyes on the separation have been examined to find that the rod pigment from the compound eye masks much of the signal from biogenic amines. The brains of white mutant flies, which have characteristically low pigment in the eyes, have a significantly simplified separation profile in comparison to the red-eyed, wild-type, Canton S fly. Yet, the white mutant flies were found to have significantly less amounts of dopamine, 1-3,4-dihydroxyphenylalanine (L-DOPA), salsolinol, and N-acetyl-tyramine in their dissected brains when compared to dissected brains of Canton S flies. In addition, significant variation has been observed in the dissected brains between individual flies that might be related to changes in neurotransmitter turnover. The transgenic GFP fly line (TH-GFP), for which the overall profile of biogenic amines is not found to be significantly different from Canton S, can be used to visualize the location of dopamine neurons. Biogenic amines were then quantified in throe brain regions observed to have dopamine levels, the central brain, optic lobes, and posterior superiormedial protocerebrum (PPM1) region. 10.1021/ac101603d

By exploiting the capabilities of steady-state electrochemical measurements, we have measured the inner diameter of a lipid nanotube using Fick's first law of diffusion in conjunction with an imposed linear concentration gradient of electroactive molecules over the length of the nanotube. Fick's law has been used in this way to provide a direct relationship between the nanotube diameter and the measurable experimental parameters [DELTA]i (change in current) and nanotube length. Catechol was used to determine the [DELTA]i attributed to its flux out of the nanotube. Comparing the nanotube diameter as a function of nanotube length revealed that membrane elastic energy was playing an important role in determining the size of the nanotube and was different when the tube was connected to either end of two vesicles or to a vesicle on one end and a pipet tip on the other. We assume that repulsive interaction between neck regions can be used to explain the trends observed. This theoretical approach based on elastic energy considerations provides a qualitative description consistent with experimental data. 10.1021/ac902282d