Neuroglial networks: neurons and glia talk to each other

Recent results show that certain neurons and glia are connected by gap junctions, and that neurons can regulate gap-junctional communication by glia. The findings are inspiring a major reexamination of the role of glia in the regulation of neuronal integration in the central nervous system.     

Morphometry of bladder carcinoma: morphometry and grading complement each other

Subjective grading of bladder carcinoma is a good predictor of the clinical outcome in those patients whose tumours are grade 1 or grade 3. However, in grade 2 tumours, which account for 45% of cases, grading has little predictive value in an individual patient. We have complemented the use of subjective grading with measurement of nuclear area and used a calculation of the distribution of nuclear sizes as a predictor of the clinical course. When subjective grading was complemented by morphometry the outcome was correctly predicted in 55 of 58 cases and all cases with poor clinical outcome were identified.     

Biochemistry and evolutionary biology: Two disciplines that need each other

Biochemical information has been crucial for the development of evolutionary biology. On the one hand, the sequence information now appearing is producing a huge increase in the amount of data available for phylogenetic analysis; on the other hand, and perhaps more fundamentally, it allows understanding of the mechanisms that make evolution possible. Less well recognized, but just as important, understanding evolutionary biology is essential for understanding many details of biochemistry that would otherwise be mysterious, such as why the structures of NAD and other coenzymes are far more complicated than their functions would seem to require. Courses of biochemistry should thus pay attention to the essential role of evolution in selecting the molecules of life.     

Cyclomaltodextrinase, neopullulanase, and maltogenic amylase are nearly indistinguishable from each other

Over 20 enzymes denoted as cyclomaltodextrinase, maltogenic amylase, or neopullulanase that share 40-86% sequence identity with each other are found in public data bases. These enzymes are distinguished from typical alpha-amylases by containing a novel N-terminal domain and exhibiting preferential substrate specificities for cyclomaltodextrins (CDs) over starch. In this research field, a great deal of confusion exists regarding the features distinguishing the three groups of enzymes from one another. Although a different enzyme code has been assigned to each of the three different enzyme names, even a single differentiating enzymatic property has not been documented in the literature. On the other hand, an outstanding question related to this issue concerns the structural basis for the preference of these enzymes for CDs. To clarify the confusion and to address this question, we have determined the structures of two enzymes, one from alkalophilic Bacillus sp. I-5 and named cyclomaltodextrinase and the other from a Thermus species and named maltogenic amylase. The structure of the Bacillus enzyme reveals a dodecameric assembly composed of six copies of the dimer, which is the structural and functional unit of the Thermus enzyme and an enzyme named neopullulanase. The structure of the Thermus enzyme in complex with beta-CD led to the conclusion that Trp47, a well conserved N-terminal domain residue, contributes greatly to the preference for beta-CD. The common dimer formation through the novel N-terminal domain, which contributes to the preference for CDs by lining the active-site cavity, convincingly indicates that the three groups of enzymes are not different enough to preserve the different names and enzyme codes.