Cytochrome c-poly(acrylic acid) conjugates with improved peroxidase turnover number.

Cytochrome c-poly(acrylic acid) (cyt c-PAA) conjugates with 34-fold enchancement in peroxidase turnover number (kcat) are reported. Cyt c-PAA conjugates were prepared by carbodiimide coupling. PAA with molecular weight (Mw) ranging from 1.8k to 250k g mol-1 were employed, and the effect of PAA Mw on peroxiodase kinetics was assessed. The kcat value increased with increased Mw of PAA, ranging from 0.077(±0.002) s-1 in the absence of PAA to 2.66(±0.08) s-1 for the conjugate of cyt c with 250k PAA. Enzymatic activity studies over pH 6-8 indicated improved activity for cyt c-PAA conjugates at neutral or slightly alkaline pH. Examination of the cyt c heme spectroscopy in the presence of H2O2 revealed that formation of compound III, a reactive intermediate that leads to enzyme inactivation, was supressed in cyt c-PAA conjugates. Thus, we suggest the kcat enhancement can be attributed to acidification of the pH microenvironment and inhibition of the formation of a reactive intermediate that deactivates cyt c during the catalytic cycle.

The emergence of ecology from natural history.

The modern discipline of biology was formed in the 20th century from roots deep in the natural-history tradition, which dates from Aristotle. Not surprisingly, therefore, ecology can also be traced to natural history, especially its 19th-century tradition emphasizing the adaptive nature of organisms to their environment. During the 20th century, ecology has developed and matured from pioneering work on successional stages to mathematically rich work on ecosystem energetics. By the end of the century, ecology has made a return to its natural-history heritage, emphasizing the importance of the integrity of ecosystems in considering human interactions with the environment.

Welch, Sedgwick, and the Hopkins model of hygiene.

William H. Welch and William T. Sedgwick, two of the founding fathers of American public health, were both early generation "Hopkins Men." Sedgwick was part of the first group of graduate students to attend Johns Hopkins University, and Welch was part of the initial faculty at the University's medical school. While they never worked together as colleagues at Hopkins, both became interested in the exciting new discoveries of the microbial nature of human disease and developed similar public health programs based on this information. Sedgwick expanded upon these investigations in the new sanitary science program at MIT, where academic public health first emerged in the United States following Sedgwick's appointment in 1883. Welch, who had been exposed to European research in microbiology, promoted microbial research in pathology in Baltimore in 1884. His laboratory-based investigations expanded until they led to the formation of the country's first school of public health in 1916. Thus, a "Hopkins Model" for hygiene and public health emerged from the efforts of both Welch and Sedgwick.

The Journal of Morphology as window and mirror: reflections and glimpses on the birth of American biology.

The centennial of the Journal of Morphology provides a fitting occasion to reflect upon the condition of American biology surrounding the founding years of the Journal. The Journal was started by C.O. Whitman in 1887. At this same time, the American biological community experienced a gradual change from a community of amateurs based within the natural history tradition to a professional community based within universities with specialized research programs. Many of the changes associated with this maturation process are exhibited in the pages of the first ten volumes of the Journal. They show that the Journal played a central role in communicating research methods and questions to the growing community of professional biologists. Moreover, these same volumes provide an accurate record of the character of the morphological sciences at the end of the 19th century.