Stability of haemoglobin and of certain endoerythrocytic enzymes in vitro

A prospective study of maternal carboxyhaemoglobin and pre-eclampsia risk

We aimed to measure the relationship between early-pregnancy maternal carboxyhaemoglobin and subsequent pre-eclampsia risk. A nested case-control analysis was conducted using data from a western Washington State cohort study (1996-2004). We measured maternal whole blood carboxyhaemoglobin in 128 women who developed pre-eclampsia and 419 normotensive controls (mean gestational age at blood draw, 14.8 weeks). After adjustment for confounders, high (>/=1%) vs. low (<0.7%) carboxyhaemoglobin odds ratios [OR] and 95% confidence intervals [CI] were 4.09 [1.30, 12.9] in multiparous women, 0.53 [0.23, 1.26] in primiparae and 1.11 [0.55, 2.25] in the overall study population (parity interaction P = 0.01). The influence of parity on the association was unexpected. The association between high carboxyhaemoglobin and pre-eclampsia risk in multiparae implicates hypoxia at the fetal-maternal interface as a pathogenic mechanism. These results also suggest that the aetiology of the disease may differ according to parity.

Digestion in the tick,Argas persicus,Oken

1.Studies on the histological changes during digestion inArgas persicusreveal that the ingestion of blood is accompanied by the destruction of the existing gut epithelial cells.

2.The blood remains unlysed for 2–3 days while a new epithelium develops which contains cells that secrete a saliva-fast PAS-positive colloid that causes haemolysis.

3.Other epithelial cells remove the freed erythrocytic nuclei by phagocytosis.

4.Most of the gut cells then absorb protein from the lumen and intracellular digestion takes place leaving pure haematin granules as the waste product of the digestion of haemoglobin.

5.After the initial rapid phase of digestion only relatively few cells show signs of absorptive and digestive activity.

6.Absorption of protein is accompanied by increased alkaline phosphatase activity in the microvilli of the cell border; this activity is lost once absorption finishes and digestion begins.

7.Strong aminopeptidase activity can be demonstrated at the border of some of the protein vacuoles.

8.In vitrotests show that the gut proteinase is active only in the acid range with peaks at pH 2·6 and 3·8 and has aKmof 0·32 % with bovine serum albumin as substrate.

9.In vivodata show that digestion, after haemolysis has occurred, takes place in two phases; the first is rapid and lasts approximately 1–2 weeks and is followed by the second phase which is slow and remains constant until the next blood feed.

10.The proportion of the blood meal which remains after the rapid phase of digestion is determined by the sex and developmental stage of the tick and within each category it is constant and serves, in the absence of significant fat and glycogen reserves, as a food reserve.

David Keilin, 1887-1963

The sudden death on 27 February 1963 of David Keilin deprived the scientific world of a biologist the span of whose scientific activities is unlikely to be equalled, much less excelled, in the future. These activities extended from descriptive morphology of protists, fungi and insects to the biochemistry of respiratory enzymes and metallo-protein compounds. It is, consequently, not possible for one person to deal adequately with all aspects of his work and in this appreciation of the man and his scientific achievements the main emphasis will be on his biological work. That bearing on parasitology will be considered in some detail, whereas the later, more biochemical, work will be considered briefly as fuller accounts of it have already been given by E. F. Hartree (Biochem. J.89, 1–5), T. R. R. Mann (Biogr. Mem. Fellows R. Soc.10, 185–207) and E. C. Slater (Enzymologia, 26, 313–20). In the brief survey of his biochemical work I have made much use of summaries and reports written by Keilin himself and I have often given the essence of lines of work summed up in his own words which express his conclusions with the elegance, lucidity and brevity characteristic of his style. As I was closely associated with David Keilin and in almost daily contact with him for just on forty years, it is natural that the following account will to some extent reflect my own interests and those aspects of his personality which became manifested during long and intimate contact both in private life and collaboration in scientific and administrative work.

The Leeuwenhoek Lecture - The problem of anabiosis or latent life: history and current concept

The eight previous Leeuwenhoek Lectures covered a great variety of problems is bacteriology and virology, and each of the lecturers paid an enthusiastic tribute Antony van Leeuwenhoek as the founder of microbiology. When the Council honoured me by their invitation to deliver the ninth Leeuwen hoek Lecture I thought that it would be appropriate to devote it to the problem of anabiosis or latent life.

Proteins and molecular palaeontology

Protein taxonomy has existed as a concept at least since 1958, but despite the efforts of the past 30 years, comparative studies of protein sequence, structure and distribution have not revolutionized any areas of systematics. The most interesting results of single gene phylogenies have been the anomalies, such as insulin in hystricomorphs or cytochrome c in the rattlesnake. It is likely that protein sequence information can be obtained in sufficient quality and quantity from ancient material as to change this finding? The paper will assess possibilities and the likely limitations of chemical studies of ancient protein material.

Preservation of proteins in mummified tissues

Protein material was extracted from the dessicated tissues of several Egyptian mummies and a frozen Eskimo. The distribution and degree of preservation of high molecular weight protein was analyzed by gel filtration, protein assays, amino acid analysis, and polyacrylamide gel electrophoresis. The protein has undergone considerable degradation although some high molecular weight protein (C. 130,000 daltons) remains intact. Amino acid analysis of the extracted protein indicates the basic amino acids have undergone a chemical modification and may represent a point of preferential breakdown in the polypeptide chain. Atomic absorption spectrophotometry of tissue cations suggests a correlation between degree of preservation of mummified tissue and levels of sodium salts (natron) in the tissue.

Purification and properties of human serum cholinesterase

Cholinesterase was purified from human serum by a three-stage procedure involving chromatography on DEAE-cellulose at pH4.0, an electrofocusing technique and gel filtration on Sephadex G-200. The final product was purified 13000-fold with a yield of 54%, and only one protein and one cholinesterase band could be demonstrated by polyacrylamide-disc electrophoresis. The catalytic properties appeared to be unchanged by the purification procedure. The molecular weight was determined by both ultracentrifugation in a density gradient and gel filtration, and values close to 366000 were obtained. The isoelectric point of cholinesterase was estimated to be pH3.99. The method appears suitable for the preliminary purification of the rare genetic variants of human cholinesterase.

Phenoxyethanol: protein preservative for taxonomists

Pieces of chicken heart or skeletal muscle were placed in a dilute solution of the antimicrobial agent 2-phenoxyethanol and stored at room temperature. Under these conditions, the serum albumin, lactate dehydrogenase, and malate dehydrogenase in these tissues survived in easily detectable amounts for at least 2 weeks. The surviving proteins appeared to be identical with those of fresh tissues in physical, catalytic, and immunological properties. Phenoxyethanol also preserved heart and muscle proteins of representatives of other vertebrate classes. Tissue samples collected in the analysis by biochemical taxonomists.