On one-dimensional nucleation and growth of “living” polymers I. Homogeneous nucleation

The kinetics of one-dimensional polymerization are described in terms of successive monomer additions. During homogeneous nucleation, the concentration c_n of critical nuclei is proportional to the nth power of monomer concentration c₁ and, initially, to the (n?1)th power of time.     

Studies on the survival of corn stalk rot bacteria

Summary Erwinia carotovora andPseudomonas lapsa which cause stalk rot of corn survived in soil and host tissues under different conditions.E. carotovora survived for 150 days and 90 days in sterile and unsterile soils, respectively, whileP. lapsa survived for 135 days and 75 days under similar conditions when they were added as cell suspensions.E. carotovora survived in diseased tissues for 22, 8, and 7 months at 0–5°C (refrigerator), 22–28°C (room), and 20–37°C (field) temperatures whileP. lapsa survived for 26, 10, and 9 months, respectively, under similar conditions. Seeds of Ganga 3 were found to carryP. lapsa for 14 months, when they were stored at room (22–28°C) temperature.     

Haem as a multifunctional regulator

Haem has long been known as the prosthetic group of haemoproteins such as haemoglobin, catalase and the cytochromes. Its biosynthesis is regulated by feedback mechanisms that ensure its adequate production but prevent its overaccumulation, which is highly deleterious as diseases such as porphyrias attest. However, recent years have seen rapid strides in our understanding of how haem (or more accurately haemin, its oxidized form) itself acts as an intracellular regulator of a variety of other metabolic pathways for systems that utilize oxygen.     

Cell surface components of Leishmania: identification of a novel parasite lectin?

Protozoan parasites of the genus Leishmania have a glycoconjugatesurface coat (the glycocalyx) that acts as the interface betweenthe parasite and its external environment. The prinicipal componentsof the glycocalyx, the lipophosphoglycans and the glycoinositolphospholipids,have a variety of functions that facilitate parasite survivalin both the extracellular and the intracellular stages of thelife cycle. Recently, a novel hydrophilic Leishmania protein,the Gene B protein, has been identified on the surface of infectiveparasite stages. Attachment to the surface appears to be byassociation between a region of repeated amino acids in thismolecule and components of the glycocalyx. As a consequence,the Gene B protein is exposed on the parasite surface whileother peptides are buried beneath the glycocalyx. The putativefunctions of this unusual molecule are discussed. differentially regulated genes glycoconjugates infective parasites Leishmania surface protein