First determination of the isozyme patterns of phosphoglycerate mutases (E.C.2.7.5.3) and phosphoglycerate kinases (E.C.2.7.2.3) in human tissues.

We present in this paper the first report about identification of several fractions of phosphoglycerate mutase (PGlyM) activity using starch gel electrophoresis and two different buffer systems. A typical muscle form of PGlyM was detected. It is also shown that isozymes of phosphoglycerate kinase (PGK) can be separated through the buffer system used by Spencer et al; (1964) for the phosphogluco mutase.     

Metabolism of D-mannose in Aerobacter aerogenes: evidence for a cyclic pathway

Kamel, M. Y. (Michigan State University, East Lansing), and R. L. Anderson. Metabolism of d-mannose in Aerobacter aerogenes: evidence for a cyclic pathway. J. Bacteriol. 92:1689-1697. 1966.-Evidence is presented which suggests a cyclic pathway for the constitutive utilization of d-mannose in extracts of Aerobacter aerogenes PRL-R3. d-Mannose is phosphorylated with d-glucose-6-phosphate to yield d-mannose-6-phosphate and d-glucose. d-Glucose-6-phosphate may be regenerated by isomerization of d-mannose-6-phosphate through d-fructose-6-phosphate, or by phosphorylation of d-glucose with adenosine-5'-triphosphate. The pathway involves the participation of four constitutive enzymes: d-glucose-6-phosphate isomerase, d-mannose-6-phosphate isomerase, a stereospecific d-glucokinase, and a phosphotransferase which phosphorylates d-mannose with d-glucose-6-phosphate, acetyl phosphate, or carbamyl phosphate. The absence of d-mannokinase (adenosine-5'-triphosphate:d-mannose phosphotransferase) activity in extracts of this organism suggests that the pathway may be of functional significance. Also, the pathway accounts for an apparent 2-epimerization of d-mannose to d-glucose that was observed in extracts.     

Osmotic adjustment in three succulent species of Zygophyllaceae

Three species, Zygophyllum album L., Z. coccineum L. and Z. simplex L., from family Zygophyllaceae were collected from two locations in Egypt to study their response to environmental conditions. Organic solutes (amino acids, soluble proteins and soluble sugars) and inorganic solutes (Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl^?, PO₄^3? and SO₄^2?) were estimated to study their role in osmotic adjustment under the effect of drought and salinity. The study showed that Z. coccineum is most tolerant for drought and salinity than Z. simplex. Z. coccineum was dependent on soluble proteins and soluble sugars, to increase its content of bound water, to undergo water deficit in desert. Z. simplex accumulated inorganic solutes more than Z. coccineum and less organic solutes. Amino acids content increased in Z. coccineum and Z. simplex survived in saline conditions to play a role in osmotic adjustment. Under the effect of salinity, all the studied species showed a tendency and high capacity to accumulate inorganic solutes. The main inorganic salutes were Ca²⁺, Mg²⁺ and Cl^?. The role of Na⁺ was less than Ca²⁺ and Mg²⁺. Z. album and Z. simplex preferred Mg²⁺ more than Z. coccineum which preferred Ca²⁺.     

A profile for molecular biology databases and information resources

This paper examines the requirements for building database managementsystems and multi-database information resources to supportmolecular biology research. The paper profiles the most importantfeatures of 16 integrated resources and 102 databases relatedto molecular biology research. The aspects surveyed in thispaper include the nature of information in these databases,their sizes, update properties, cross-references, database managementsystem heterogeneity, geographical distribution, data quality,use of temporal information and level of interpretation. Thepaper also comments on the access patterns to these databases.Since not all these aspects were available for all databases,specific comparisons sometimes compare fewer than the full 102databases. Consequently, the same set of databases is not necessarilyalways being compared with respect to every aspect. The paperis organized primarily according to these comparison aspectsand ends with some concluding remarks.