Relationship between age of culture and occurrence of the pigments of photosystem II of photosynthesis in heterocysts of a blue-green alga

Microspectrophotometric examination of the pigments in vivo of heterocysts of Anabaena sp. L-31 has shown that most heterocysts of 2-day-old cultures possess only very small amounts, if any, of c-phycocyanin, allo-phycocyanin, and c-phycoerythrin, the main pigments comprising photosystem II of photosynthesis. The quantities of these pigments, however, increase with age of cultures, and by the end of 5 days the majority of heterocysts contain comparatively large amounts. The culmination of this sequential development is observed in most heterocysts of 7- to 15-day-old cultures when the full complement of photosystem II pigments is present. The spectral characteristics at this stage are similar to those of vegetative cells and suggest a dedifferentiation of heterocysts.

Chemical compositions of elastins isolated from aortas and pulmonary tissues of humans of different ages

1. Elastins were isolated from the visceral pleuras and parenchymas of lungs of humans of different ages. 2. The elastin content of pleuras increased whereas that of parenchymas remained constant with increasing age. 3. The amino acid compositions and carbohydrate contents of elastins isolated from both pulmonary tissues changed in the same way with increasing age of the subjects. These changes were similar to those observed in elastins isolated from the aorta. 4. Similar glycoproteins were isolated from pleuras and aortas, and were more difficult to extract from the elastins of older subjects. Contamination with these glycoproteins was responsible for the changes in composition of elastin, as the age of the tissue from which it was extracted increased. 5. The amount of the cross-linking amino acids desmosine and isodesmosine was lower in elastins isolated from both aorta and pulmonary tissues of senile subjects than those from younger subjects.

The Effects of Shear Deformation and Rotary Inertia on the Lateral Frequencies of Cantilever Beams in Bending

This paper deals with the effect of shear deformation and rotary inertia on the frequencies of flexural vibration of pre-twisted and non-pre-twisted uniform and tapered cantilever beams. The equations of motion are derived and transformed into a set of linear simultaneous algebraic equations by using finite-difference solutions for the derivatives. The resulting eigenvalue matrix equation is solved for the frequency parameters by a QR transformation. The effects of various tapers, depth-to-length ratios and pre-twist angles on the frequencies of vibration are investigated for the first five modes. Results obtained are compared with those presented by other investigators where available and show good agreement. The experimental results presented also show good agreement with the corresponding theoretical values.

The Coupled Bending—Bending Vibration of Pre-Twisted Tapered Blading

The work of this paper deals with the coupled bending–bending vibration of pre-twisted tapered cantilever blades. The equations of motion are established for a beam tapered in width (or depth) only and for a blade tapered in both width and depth. The equations are solved to obtain the frequencies and modal shapes and the theoretical results are compared with corresponding experimental values. Close agreement is obtained between the calculated and measured results. It is shown that taper has a considerable influence on both the frequencies of vibration and the associated modal shapes.

Effect of monosodium n-alkylsalicylates on spores of Bacillus subtilis

The effects of several monosodium n-alkylsalicylates on washed spores of Bacillus subtilis have been examined. None of the compounds was sporicidal, but in general they prevented dormancy induced by incubating the spores in water. This effect was related to the position in the ring and size of the alkyl groups substituted on the salicylic acid nucleus.

The binding of bupivacaine to maternal and foetal plasma proteins

The binding of bupivacaine to maternal and foetal plasma proteins has been investigated using a three-compartment dialysis apparatus, in which maternal and foetal plasma could be examined simultaneously. Maternal protein bound approximately twice as much bupivacaine as foetal protein per gram of protein at drug concentrations in the range 0·05 to 5·0 μg/ml. Over the same range of concentrations, 92–78% of bupivacaine was bound to maternal plasma protein but only 35–31% was bound to human albumin indicating that other proteins are involved in the binding of the drug to plasma proteins.

Antimicrobial activity of sodium n-alkylsalicylates

The activities are reported of sodium salts of several n-alkylsalicylic acids against Staphylococcus aureus, Pseudomonas aeruginosa, Mycobacterium phlei, and Candida albicans. The acids had alkyl substituents of 1 to 18 carbon atoms in the 3, 4, or 5 positions relative to the carboxyl group of salicylic acid. Generally, the antimicrobial properties were typical of anionic surface-active agents although the salicylates are more potent than most of these, particularly against S. aureus.