Physical structures of Tn10-promoted deletions and inversions: role of 1400 bp inverted repetitions.

We report here the physical structures of deletions and inversions promoted by the translocatable tetracycline-resistance element Tn10. DNA/DNA heteroduplex and restriction enzyme analyses of alterations in the genome of bacteriophage lambda suggest that both types of DNA alterations almost always originate at the internal termini of the 1400 bp terminal inverted repetitions of Tn10. Tn10-promoted deletions remove a single contiguous DNA segment beginning at one such terminus; Tn10-promoted inversions are more complex, and involve both an inversion and a specific deletion of Tn10 DNA.     

Potential yields and properties of oil from the hydrothermal liquefaction of microalgae with different biochemical content

A range of model biochemical components, microalgae and cyanobacteria with different biochemical contents have been liquefied under hydrothermal conditions at 350 °C, ∼200 bar in water, 1 M Na₂CO₃ and 1 M formic acid. The model compounds include albumin and a soya protein, starch and glucose, the triglyceride from sunflower oil and two amino acids. Microalgae include Chlorella vulgaris,Nannochloropsis occulata and Porphyridium cruentum and the cyanobacteria Spirulina. The yields and product distribution obtained for each model compound have been used to predict the behaviour of microalgae with different biochemical composition and have been validated using microalgae and cyanobacteria. Broad agreement is reached between predictive yields and actual yields for the microalgae based on their biochemical composition. The yields of bio-crude are 5-25 wt.% higher than the lipid content of the algae depending upon biochemical composition. The yields of bio-crude follow the trend lipids > proteins > carbohydrates.     

Evidence that humidity influences snake activity patterns: a field study of the Malayan pit viper Calloselasma rhodostoma

Multivariate statistical methods were used to elucidate which environmental factors influence the activity patterns of free-living Malayan pit vipers, Calloselasma rhodostoma. Fourteen adult snakes were implanted with miniature radiotransmitters and located a total of 887 times in 5 months. The pit vipers usually remained coiled on the ground for several consecutive days before moving at night to a new site. Partial correlation tests revealed that the frequency and distance of movements to new sites by tagged snakes were highly positively correlated with ambient relative humidity, but not with rainfall, ambient temperature or the lunar cycle. This finding was corroborated by the frequency with which active non-tagged C. rhodostoma were encountered at night, In each site, the proportion of the snakes' bodies exposed to view was positively correlated with ambient humidity, and the snakes retreated to areas with deeper undergrowth when ambient humidity was low. Overt thermoregulatory behaviour was not observed, and implanted thermosensitive transmitters revealed that the snakes were passive thermoconformers.
These findings seem lo contradict much of the current literature which shows temperature to be the dominant abiotic factor affecting reptilian activity, but most herpetologists have considered only temperate forms. Ambient temperature in our tropical study site was warm and relatively constant throughout the year (mean daily range = 24- 33°C), so the pit vipers could passively maintain body temperature within a fairly narrow range, with a daytime mean of 29.4°C. Ambient relative humidity, on the other hand, was very variable, and confining exposure and activity to periods of high ambient humidity may be necessary to avoid dehydration     

Seasonal variation in the chemical composition of the bioenergy feedstock Laminaria digitata for thermochemical conversion

To avoid negative impacts on food production, novel non-food biofuel feedstocks need to be identified and utilised. One option is to utilise marine biomass, notably fast-growing, large marine ‘plants’ such as the macroalgal kelps. This paper reports on the changing composition of Laminaria digitata throughout it growth cycle as determined by new technologies. The potential of Laminaria sp. as a feedstock for biofuel production and future biorefining possibilities was assessed through proximate and ultimate analysis, initial pyrolysis rates using thermo-gravimetric analysis (TGA), metals content and pyrolysis gas chromatography-mass spectrometry.Samples harvested in March contained the lowest proportion of carbohydrate and the highest ash and alkali metal content, whereas samples harvested in July contained the highest proportions of carbohydrate, lowest alkali metals and ash content. July was therefore considered the most suitable month for harvesting kelp biomass for thermochemical conversion to biofuels.     

Galanin-Like Immunoreactivity Is Unchanged in Alzheimer''s Disease and Parkinson''s Disease Dementia Cerebral Cortex

Galanin is a recently isolated neuropeptide that is of particular interest in dementing disorders because of its known colocalization with choline acetyltransferase in magnocellular neurons of the basal nucleus of Meynert. These neurons degenerate in Alzheimer's disease, and there is a corresponding deficiency of cortical choline acetyltransferase activity. In the present study, galanin-like immunoreactivity was measured in the postmortem cerebral cortex and hippocampus of 10 controls and 14 patients who had had Alzheimer's disease. Significant reductions of choline acetyltransferase activity (50-60%) were found in all regions examined; however, there was no significant effect on concentrations of galanin-like immunoreactivity. Similar measurements were made in postmortem tissues of 12 control and 13 demented Parkinsonian patients who had had Alzheimer-type cortical pathology. Choline acetyltransferase activity was again significantly decreased in all regions examined but there were no significant reductions in galanin-like immunoreactivity. Experimental lesions of the fornix in rats produced parallel significantly correlated reductions of both choline acetyltransferase activity and galanin-like immunoreactivity in the hippocampus. Galanin-like immunoreactivity in the human hypothalamus consisted of two molecular-weight species on gel-permeation chromatography, and two forms were resolved by reverse-phase HPLC. The paradoxical preservation of galanin-like immunoreactivity, despite depletion of the activity of choline acetyltransferase, with which it is colocalized, is as yet unexplained. Recent studies have shown that galanin inhibits both acetylcholine release in the hippocampus and memory acquisition; therefore, preserved galanin may exacerbate the cholinergic and cognitive deficits that accompany dementia.