The late elongated hypocotyl mutation of Arabidopsis disrupts circadian rhythms and the photoperiodic control of flowering

The dominant late elongated hypocotyl (lhy) mutation of Arabidopsis disrupted circadian clock regulation of gene expression and leaf movements and caused flowering to occur independently of photoperiod. LHY was shown to encode a MYB DNA-binding protein. In wild-type plants, the LHY mRNA showed a circadian pattern of expression with a peak around dawn but in the mutant was expressed constantly at high levels. Increased LHY expression from a transgene caused the endogenous gene to be expressed at a constant level, suggesting that LHY was part of a feedback circuit that regulated its own expression. Thus, constant expression of LHY disrupts several distinct circadian rhythms in Arabidopsis, and LHY may be closely associated with the central oscillator of the circadian clock.     

Chemical and sensory analysis of strawberry flavoured yogurt supplemented with an algae oil emulsion

A yogurt mix (2 g fat and 17g solids/100 g) was supplemented with an algae oil emulsion to provide 500 mg omega-3 fatty acids per 272 g serving of yogurt white mass. The emulsion was added to the yogurt mix either before or after the homogenization step and prior to pasteurization. It was then flavoured with a strawberry fruit base and fermented and stored for up to three weeks. The oxidative deterioration of the products was determined by hydroperoxide measurements and by trained and consumer sensory evaluations. The hydroperoxide content of the supplemented yogurts increased over the storage treatment and was unaffected by the stage of addition. The trained panel could distinguish a stronger fishy flavour in both of the supplemented yogurts after 22 days storage, but the consumer panel rated both control and supplemented samples similarly, as 'moderately liked'.     

Acceptability and Digestibility of Emulsions in a Rat Model: Effects of Solid Fat Content and Lipid Type

The present study sought to determine if alterations in the chemical nature and form of fat in food would reduce digestibility while maintaining acceptability in rats. Oil-in-water emulsions (d < 1 μm) were prepared with either liquid palm oil, solid hydrogenated palm oil or solid docosane, all stabilized with sodium caseinate. The emulsions were incorporated into a fat-free rodent feed, and each offered over 5 days to separate cohorts of 12 male Sprague–Dawley rats housed in metabolic cages. The feed formulated with solid hydrogenated palm oil was significantly less acceptable than the feeds containing either liquid palm oil or docosane (feed intake 4.9, 26.6 and 32.1 g/animal/day respectively). The proportion of the fat retained (i.e. absorbed) was significantly less in the animals consuming the feed formulated with solid docosane than in the animals consuming either the liquid or solid palm oil (retention 8.7, 99.6, and 97.2%, respectively). The appearance of the feces from the rats fed docosane was different from the rats fed the triacylglycerol samples and thermal analysis revealed many of the solid alkane droplets had not coalesced during passage through the rat’s digestive system. These results indicate that indigestible fats can be packaged into food in a manner that does not compromise the acceptability of the product, and does not produce any apparent intestinal distress.     

Early macular dysfunction detected by focal electroretinographic recording in non-insulin-dependent diabetics without retinopathy

The focal electroretinogram, which measures the functional integrity of the distal retina of the macula, was recorded with a hand-held stimulator-ophthalmoscope in 26 eyes from patients with non-insulin-dependent diabetes mellitus with normal fundus photography, and in 52 control eyes of similar age range. Implicit time and amplitude of the responses were studied as a function of the age, glycemic control through glycosylated hemoglobin measurement and duration of diabetes. Implicit time and amplitude were significantly delayed (F=5.05, p=0.028) and reduced (F=11.26, p=0.013) in diabetic patients without diabetic retinopathy compared to control subjects. Moreover, there was a significant relationship between the implicit time (r=0.57, p=0.002) and amplitude (r=-0.65, p=0.0004) with the duration of diabetes but not with hemoglobin Alc. These results strongly suggest an early macular dysfunction in non-insulin-dependent diabetes mellitus before the appearance of diabetic retinopathy.     

Ultrasonic determination of the effect of shear on lipid crystallization

The design and calibration of a novel rheometer incorporating ultrasonic sensors are described. The instrument is capable of the simultaneous measurements of torque, rate of temperature change, and ultrasonic properties of a liquid as a function of time, temperature, and shear rate. The effect of shear rate on the crystallization onset temperature of a sample of confectionery coating fat is studied using this device. The instrument detected the phase transition in the sheared sample as abrupt changes in all of the measured parameters. The onset temperature increased significantly with shear rate, implying lipid crystallization can be accelerated by mixing. There were also significant differences between sensing modalities.