Zinc – An Indispensable Micronutrient

Availability of Zn to plant is hampered by its immobile nature and adverse soil conditions. Thus, Zn deficiency is observed even though high amount is available in soil. Root-shoot barrier, a major controller of zinc transport in plant is highly affected by changes in the anatomical structure of conducting tissue and adverse soil conditions like pH, clay content, calcium carbonate content, etc. Zn deficiency results in severe yield losses and in acute cases plant death. Zn deficiency in edible plant parts results in micronutrient malnutrition leading to stunted growth and improper sexual development in humans. To overcome this problem several strategies have been used to enrich Zn availability in edible plant parts, including nutrient management, biotechnological tools, and classical and molecular breeding approaches.     

An extracellular α-l-arabinofuranosidase fromSclerotium rolfsii

Activity of -l-arabinofuranosidae (EC 3.2.1.55) ranged between 0.03 and 1.63 U/ml whenSclerotium rolfsii was grown in a synthetic medium containing different nitrogen and carbon sources. Agricultural and forest residues such as rice straw, corn cob, groundnut husk, and apple pomace were suitable substrates for enzyme production. Maximum activity, 4.2 U/ml, was with pre-treated corn cobs.The authors are with the National Chemical Laboratory, Division of Biochemistry, Pune 411 008, India     

An error catastrophe in cancer?

A comparison between the evolution of cancer cell populations and RNA viruses reveals a number of remarkable similarities. Both display high levels of plasticity and adaptability as a consequence of high degrees of genetic variation. It has been suggested that, as it occurs with RNA viruses, there is a threshold in the levels of genetic instability affordable by cancer cells in order to be able to overcome selection barriers (Trends Genet. 15 (1999) M57). Here we explore this concept by means of a simple mathematical model. It is shown that an error threshold exists in this model, which investigates both competition between cancer cell populations and its impact on overall tumor growth dynamics. Once the threshold is reached, the highly unstable tumor cell populations, which were sustaining malignant growth, become unable to maintain their genetic information, which in turn triggers a slowed down overall tumor growth regime.     

An inherited α1-antitrypsin variant

The pedigree of a family some of whose members are heterozygous for an electrophoretically slower ₁-antitrypsin variant is reported. Linkage relations to other common genetic markers have not been found.     

Water-saving Agriculture： An Urgent Issue

The twentieth century has witnessed the great effort of mankind to strive for more food production, which has led to an unprecedented increase in grain production known as the First Green Revolution. As mankind entered the 21st century, the Blue Revolution -the struggle in agriculture for better use of water resources - has just begun. Norman E. Borlaug, 1970 Nobel Peace Prize Laureate, said in 2000, “how can we continue to expand food production for a growing world population within the parameters of likely water availability？ The inevitable conclusion is that humankind in the 21st Century will need to bring about a ＇Blue Revolution - more crop for every drop＇ to complement the ＇Green Revolution＇ of the 20th Century. Water use productivity must be wedded to land use productivity. Science and technology will be called upon to show the way”.