Effects of noradrenaline on45Ca2+ efflux from isolated rat islets of Langerhans

Noradrenaline caused a prompt but transient increase in the rate of⁴⁵Ca²⁺ efflux from isolated rat islets of Langerhans perifused in Ca²⁺ depleted medium. The response was modest in size and was unaffected by isosmotic replacement of NaCl with choline chloride or by inclusion of 0.5 mM dibutyryl cAMP in the perifusion medium, suggesting that it was not mediated by Na+: Ca²⁺ exchange nor by lowered cAMP. Despite its effect on⁴⁵Ca²⁺ efflux, noradrenaline treatment did not alter the kinetics of⁴⁵Ca²⁺ efflux in response to the muscarinic agonist, carbamylcholine, nor did it change the magnitude of the response to this agent. Simultaneous introduction of 20 mM glucose with noradrenaline prevented a rise in⁴⁵Ca²⁺ efflux and indeed resulted in inhibition of⁴⁵Ca²⁺ efflux. The data suggest that noradrenaline does not directly activate the mechanisms which regulate Ca²⁺ extrusion from islets cells, and they do not support a primary role for the Ca²⁺ efflux response in mediating adrenergic inhibition of insulin secretion.     

Development of a fermentation procedure to produce a tempe-related food using common beans as substrate

Summary A basic procedure was developed to produce a tempe-like product using the mouldRhizopus oligosporus and black common beans (Phaseolus vulgaris) as substrate. The initial pH of the substrate was 5.8, and fermentation was conducted at 37°C with a relative humidity of 70% for 72 hrs. Levels of soluble solids and soluble protein increased dramatically as a result of fermentation. Some changes were as well observed in fatty acid contents of fermented samples. It was concluded that the common bean used was an acceptable substrate for preparing this product.     

A new method for the quantitative determination of monosaccharides, amino sugars and N-acetylneuraminic acid and of 6-deoxyhexose (fucose) in the presence of other sugars

1. Monosaccharides, amino sugars and N-acetylneuraminic acid were determined by using an original colorimetric assay procedure, based on the detection of formaldehyde released after periodate oxidation. A range of these compounds was investigated by this method and they were all found to obey Beer's law within the concentration range 0-0.6mumole/ml. 2. A simple method for the determination of 6-deoxyhexose concentration in the presence of other monosaccharides is also described. 3. The optimum pH for the release of formaldehyde from sugars by periodate oxidation was 7.0-7.5. 4. The methods described have considerable advantages over existing assay systems and their particlar value in automatic colorimetry, where the use of concentrated acids is undesirable, is discussed.     

The effect of inhibition of hexosemonophosphate shunt on the metabolism of glucose and function in rat brain in vivo

Rats treated 4 hr previously with 6-aminonicotinamide showed a twenty-four fold increase of [¹⁴C]phosphogluconate in the adult brain at 30 min after injection of [U-¹⁴C]glucose indicating a blockade of the hexosemonophosphate shunt. There was a significant increase in the¹⁴C-content of glucose and glucose 6-phosphate, and a decrease in that of amino acids. [¹⁴C]Phosphoglycerate content showed no consistent change after 6-aminonicotinamide treatment. The concentration of glucose and glucose 6-phosphate increased significantly without a significant change in the lactate pool in the brain of 6-aminonicotinamide treated rats. The rate of utilization of glucose in the brain of control rats was 0.73 mol/min per g of brain. It decreased by 16% in rats treated with 6-aminonicotinamide; the results suggested that both glycolysis and pyruvate oxidation were affected. The amount of glucose utilized in the brain by the hexosemonophosphate shunt was approximately 0.0093 mol/min per g of brain, i.e. 1.3% of the total rate of utilization of glucose. The observed changes were not due to hypothermia. The rate of glucose utilization was higher in animals exposed to higher ambient temperature and to stress caused by handling. The results were explained by postulating a role for the hexosemonophosphate shunt in providing neurotransmitter amino acids glutamate and -aminobutyrate, and interdependence of brain function and glucose utilization.This paper is dedicated to Dr. Derek Richter on his seventy-fifth birthday.     

Isolation and characterization of bacteriophages infecting Salmonella spp

Bacteriophages infecting Salmonella spp. were isolated from sewage using soft agar overlays containing three Salmonella serovars and assessed with regard to their potential to control food-borne salmonellae. Two distinct phages, as defined by plaque morphology, structure and host range, were obtained from a single sample of screened sewage. Phage FGCSSa1 had the broadest host range infecting six of eight Salmonella isolates and neither of two Escherichia coli isolates. Under optimal growth conditions for S. Enteritidis PT160, phage infection resulted in a burst size of 139 PFU but was apparently inactive at a temperature typical of stored foods (5 degrees C), even at multiplicity of infection values in excess of 10 000. While neither isolate had characteristics that would make them candidates for biocontrol of Salmonella spp. in foods, phage FGCSSa1 behaved unusually when grown on two Salmonella serotypes at 37 degrees C in that the addition of phages appeared to retard growth of the host, presumably by the lysis of a fraction of the host cell population.     

Escape behaviors in insects

Escape behaviors are, by necessity, fast and robust, making them excellent systems with which to study the neural basis of behavior. This is especially true in insects, which have comparatively tractable nervous systems and members who are amenable to manipulation with genetic tools. Recent technical developments in high-speed video reveal that, despite their short duration, insect escape behaviors are more complex than previously appreciated. For example, before initiating an escape jump, a fly performs sophisticated posture and stimulus-dependent preparatory leg movements that enable it to jump away from a looming threat. This newfound flexibility raises the question of how the nervous system generates a behavior that is both rapid and flexible. Recordings from the cricket nervous system suggest that synchrony between the activity of specific interneuron pairs may provide a rapid cue for the cricket to detect the direction of an approaching predator and thus which direction it should run. Technical advances make possible wireless recording from neurons while locusts escape from a looming threat, enabling, for the first time, a direct correlation between the activity of multiple neurons and the time-course of an insect escape behavior.     

Participant understanding and recall of informed consent for induced pluripotent stem cell biobanking

The ability to generate human induced pluripotent stem cells (iPSCs) has opened new avenues for human disease modelling and therapy. The aim of our study was to determine research participants’ understanding of the information given when donating skin biopsies for the generation of patient-specific iPSCs. A customised 35-item questionnaire based on previous iPSC consent guidelines was sent to participants who had previously donated samples for iPSC research. The questionnaire asked pertinent demographic details, participants' motivation to take part in iPSC research and their attitudes towards related ethical issues. 234 participants were contacted with 141 (60.3 %) complete responses received. The median duration between recruitment and follow-up questioning was 313 days (range 10–573 days). The majority of participants (n = 129, 91.5 %) believed they understood what a stem cell was; however, only 22 (16.1 %) correctly answered questions related to basic stem cell properties. We found no statistically significant difference in responses from participants with different levels of education, or those with a health sciences background. The poor understanding amongst participants of iPSC research is unlikely to be unique to our study and may impact future research if not improved. As such, there is a need to develop an easily understood yet comprehensive consent process to ensure ongoing ethical progress of iPSC biobanking.