Microcomputer interfacing to mass flow type gas controllers for biotechnology applications

Summary An Apple IIe microcomputer with an Isaac analog-digital package has been interfaced to Tylan proportionating mass flow gas controllers to regulate three substrate gases which are introduced into an anaerobic bioreactor. Advantages of the system include: straightforward interfacing and programming, accurate monitoring and controlling, and advanced real time control capabilities.     

Unravelling developmental disregard in children with unilateral cerebral palsy by measuring event-related potentials during a simple and complex task

Background

In a subset of children with unilateral Cerebral Palsy (CP) a discrepancy between capacity and performance of the affected upper limb can be observed. This discrepancy is known as Developmental Disregard (DD). Though the phenomenon of DD has been well documented, its underlying cause is still under debate. DD has originally been explained based on principles of operant conditioning. Alternatively, it has been proposed that DD results from a diminished automaticity of movements, resulting in an increased cognitive load when using the affected hand. To investigate the amount of involved cognitive load we studied Event-Related Potentials (ERPs) preceding task-related motor responses during a single-hand capacity and a dual-hand performance task. It was hypothesised that children with DD show alterations related to long-latency ERP components when selecting a response with the affected upper limb, reflecting increased cognitive load in order to generate an adequate response and especially so within the dual-hand task.

Methods

Fifteen children with unilateral CP participated in the study. One of the participants was excluded due to major visual impairments. Seven of the remaining participants displayed DD. The other seven children served as a control group. All participants performed two versions of a cue-target paradigm, a single-hand capacity and a dual-hand performance task. The ERP components linked to target presentation were inspected: the mid-latency P2 component and the consecutive long-latency N2b component.

Results

In the dual-hand performance task children with DD showed an enhancement in mean amplitude of the long-latency N2b component when selecting a response with their affected hand. No differences were found regarding the amplitude of the mid-latency P2 component. No differences were observed regarding the single-hand capacity task. The control group did not display any differences in ERPs linked to target evaluation processes between both hands.

Conclusion

These electrophysiological findings show that DD is associated with increased cognitive load when movements are prepared with the affected hand during a dual-hand performance task. These findings confirm behavioural observations, advance our insights on the neural substrate of DD and have implications for therapy.     

The stress responsive and morphologically regulated <Emphasis Type="Italic">hsp90</Emphasis> gene from <Emphasis Type="Italic">Paracoccidioides brasiliensis</Emphasis> is essential to cell viability

Background  

Paracoccidioides brasiliensis is a dimorphic fungus that causes the most prevalent systemic mycosis in Latin America. The response to heat shock is involved in pathogenesis, as this pathogen switches from mycelium to yeast forms in a temperature dependent fashion that is essential to establish infection. HSP90 is a molecular chaperone that helps in the folding and stabilization of selected polypeptides. HSP90 family members have been shown to present important roles in fungi, especially in the pathogenic species, as an immunodominant antigen and also as a potential antifungal therapeutic target.     

Do we know enough? A scientific and ethical analysis of the basis for genetic-based personalized nutrition

This article discusses the prospects and limitations of the scientific basis for offering personalized nutrition advice based upon individual genetic information. Two divergent scientific positions are presented, with an ethical comment. The crucial question is whether the current knowledge base is sufficiently strong for taking an ethically responsible decision to offer personalized nutrition advice based upon gene–diet–health interaction. According to the first position, the evidence base for translating the outcomes of nutrigenomics research into personalized nutritional advice is as yet immature. There is also limited evidence that genotype-based dietary advice will motivate appropriate behavior changes. Filling the gaps in our knowledge will require larger and better randomized controlled trials. According to the second position, personalized nutrition must be evaluated in relation to generally accepted standard dietary advice—partly derived from epidemiological observations and usually not proven by clinical trials. With personalized nutrition, we cannot demand stronger evidence. In several specific cases of gene–diet interaction, it may be more beneficial for individuals with specific genotypes to follow personalized advice rather than general dietary recommendations. The ethical comment, finally, considers the ethical aspects of deciding how to proceed in the face of such uncertainty. Two approaches for an ethically responsible way forward are proposed. Arguing from a precautionary approach, it is suggested that personalized dietary advice should be offered only when there is strong scientific evidence for health effects, followed by stepwise evaluation of unforeseen behavioral and psychological effects. Arguing from theoretical and applied ethics as well as psychology, it is also suggested that personalized advice should avoid paternalism and instead focus on supporting the autonomous choice of each person.     

Hybridization in sunfish influences the muscle metabolic phenotype

Hybridization has the potential to exert pleiotropic effects on metabolism. Effects on mitochondrial enzymes may arise through incompatibilities in nuclear- and mitochondrial-encoded subunits of the enzyme complexes of oxidative phosphorylation. We explored the metabolic phenotype of bluegill (Lepomis macrochirus), pumpkinseed (Lepomis gibbosus), and their unidirectional F(1) hybrids (male bluegill × female pumpkinseed). In hybrids, glycolytic enzyme activities were indistinguishable from (aldolase, pyruvate kinase) or intermediate to (lactate dehydrogenase, phosphoglucoisomerase) parentals, but complex IV activities aligned with pumpkinseed, both 30% lower than bluegill. In isolated mitochondria, the specific activities of complexes I, II, and V were indistinguishable between groups. However, both complex III and IV showed indications of depressed activities in hybrid mitochondria, though no effects on mitochondrial state 3 or state 4 respiration were apparent. The patterns in complex IV activities were due to differences in enzyme content rather than enzyme V(max); immunoblots comparing complex IV content with catalytic activity were indistinguishable between groups. The sequence differences in complex IV catalytic subunits (CO1, CO2, CO3) were minor in nature; however, the mtDNA-encoded subunit of complex III (cytochrome b) showed eight differences between bluegill and pumpkinseed, several of which could have structural consequences to the multimeric enzyme, contributing to the depressed complex III catalytic activity in hybrids.     

Polycationic lipids translocate lipopolysaccharide into HeLa cells

We have investigated the ability of LIPOFECTAMINE, a polycationic lipid reagent used in DNA transfection, to translocate E. coli lipopolysaccharide (LPS) into HeLa cells. Although HeLa cells did not spontaneously take up fluorescein isothiocyanate-labelled LPS (FITC-LPS) from the culture medium, the cells that were co-incubated with greater than 1 g/mL FITC-LPS and LIPOFECTAMINE showed punctate fluorescence. Virtually all cells were loaded on incubation with 100 micrograms/mL FITC-LPS. Confocal scanning laser microscopy showed extensive FITC-LPS loading in the cytoplasm of HeLa cells, but no label was evident in the nuclear regions of these cells. Loading with LPS for up to six hours had no effect on the viability of HeLa cells, beyond the 30% reduction in live cells that is attributable to the toxic effect of LIPOFECTAMINE itself. In contrast to cells treated with etoposide for six hours, LPS-loaded cells did not display apoptotic bodies. Exposure of cells to 4 beta-phorbol 12-myristate 13-acetate led to the induction of the immediate early gene c-fos and resulted in an enhanced c-Fos signal, detected by Western blot analysis. In contrast, LPS loading did not alter the c-fos expression in HeLa cells. The loading of LPS into HeLa cells by means of polycationic lipids results in relatively low acute toxicity, as judged from cell viability, morphology and c-fos expression. Therefore, our method appears well suited to the study of acute actions of LPS in the intracellular compartment of mammalian cells.