D. L. N. Rao

Parapedobacter indicus sp. nov., isolated from hexachlorocyclohexane-contaminated soil

Strain RK1(T), a Gram-stain-negative, non-spore-forming, rod-shaped, non-motile bacterium was isolated from a hexachlorocyclohexane (HCH) dumpsite, Lucknow, India. 16S rRNA gene sequence analysis revealed that strain RK1(T) belongs to the family Sphingobacteriaceae and showed highest sequence similarity to Parapedobacter koreensis Jip14(T) (95.63%). The major cellular fatty acids of strain RK1(T) were iso-C15:0, summed feature 3 (C16:1ω7c and/or C16:1ω6c), iso-C17:0 3-OH, summed feature 9 (10-methyl C16:0 and/or iso-C17:1ω9c), iso-C15:0 3-OH and C16 : 0. The major respiratory pigment and polyamine of RK1(T) were menaquinone (MK-7) and homospermidine, respectively. The main polar lipids were phosphatidylethanolamine and sphingolipid. The G+C content of the DNA was 44.5 mol%. The results of physiological and biochemical tests and 16S rRNA sequence analysis clearly demonstrated that strain RK1(T) represents a novel species of the genus Parapedobacter, for which the name Parapedobacter indicus sp. nov. is proposed. The type strain is RK1(T) ( = DSM 28470(T) =MCC 2546(T)).

Experiments in soil biology and biochemistry: P. K. Chhonkar, S. Bhadraray, A. K. Patra and T. J. Purkayastha, 2007, Westville Publishing House, New Delhi 182 pp, Rs. 600.

Soil ecosystems remain fi rmly at the foundations of human life support systems. They are the least understood and also among the most degraded. Impaired soil health is a leading contributor to reduced crop yields and poverty. Global warming is likely to further exacerbate the problem. All these concerns have naturally led to an increased attention to the microbiology of soils and to a new surge of interest in soil biodiversity, soil health indicators and their measurement. The study of theoretical and practical soil biology is now essential curriculum for not only students of microbiology and soil science but also agronomy, forestry and environmental science. A need for a practical manual on methods of soil biology has been a felt in order to ensure the use of uniform and standardized methods for various soil types and situations, which is fulfi lled by this book. The book is divided into six sections: Enumeration of Soil Biota; Determining Soil Biological Activity; Soil Enzymes; Biochemical Transformations of Nitrogen; Soil Biotechnology and Biological Methods of Soil Fertility Measurement. There are 29 chapters covering the various measurements in the six sections. The methods given in most cases are easy to follow with suffi cient details and are executable in a post-graduate laboratory. The sections on soil enzymes, biological activity, N transformations and biological soil fertility assessment are well written. Of particular interest to students and researchers would be the classical methods for enumeration of soil protozoa and bioassay of available potassium. The book is well illustrated with line diagrams to describe practical procedures and with four color plates to familiarize students with various groups of micro-biota. The book is extremely well produced and printed. Like all good books have their share of drawbacks, this book also has few which need attention in the second edition. In the chapter on counting of bacteria in soil (1.1), the student should be introduced to the concept of non-proportionality factor during dilution and hence the rules of counting. The chapter on Rhizobium (1.2) should include a section on strain authentication by physiological, biochemical and nodulation tests. The section on soil biotechnology while being useful to the student as a source of information on the modern approaches, but would not be directly useful for measuring soil biodiversity changes in various farming situations/management interventions, as that would require a much more detailed treatment of the subject and methodology. The chapter on ‘BIOLOG’ also needs updating with latest procedures. Fortunately, there are very few spelling mistakes due to good production (except in chapter 5.1 on extraction of genomic DNA from soil) which need correction in future edition. Overall, the authors have done a very good job borne out their of long experience of teaching and practical exercises for the soil biology course at the Indian Agricultural Research Institute, New Delhi, and deserve compliments. The cost of the book is steep and a paper-back priced more modestly would serve most laboratories/colleges/students well.

Draft Genome Sequence of Hexachlorohexane (HCH)-Degrading Sphingobium lucknowense Strain F2T, Isolated from an HCH Dumpsite

ABSTRACT Sphingobium lucknowense F2T, isolated from the hexachlorocylcohexane (HCH) dumpsite located in Ummari village, Lucknow, India, rapidly degrades HCH isomers. Here we report the draft genome of strain F2 (4.4 Mbp), consisting of 4,910 protein coding genes with an average G+C content of 64.3%.

Microbial Populations, Activity and Gene Abundance in Tropical Vertisols Under Intensive Chemical Farming

There are increasing concerns on the environmental impacts of intensive chemical agriculture. The effect of high agrochemical inputs used in intensive chemical farming was assessed on soil microbiological, molecular and biochemical properties in tropical Vertisols in India. Farm field sites under normal cultivation of arable crops using high inputs of fertilizers and pesticides in chili (Capsicum annum L., 5.0× dose for fertilizers and 1.5× dose for pesticides over normal inputs) and black gram (Vigna mungo L. Hepper, 2.2× dose for fertilizers and 2.3× dose for pesticides over normal inputs) were compared with adjacent sites using normal recommended doses. Organic carbon and basal respiration showed no response to high inputs of fertilizers and pesticides in soils of both crops. Labile carbon decreased by 10% in chili soils and increased by 24% in black gram soils under high input farming system. The proportion of soil labile carbon as a fraction of soil organic carbon was unaffected by high inputs. The labile carbon mineralization coefficient (qMLC) increased by 50.0% in chili soils, indicating that the soil microorganisms were under stress due to high agochemical inputs, whereas qMLC decreased by 36.4% in black gram soils. Copiotrophs increased due to high inputs in soils of both chili (63.1%) and black gram (47.1%). Oligotrophs increased by 10.8% in black gram soils but not in chili soils. The abundance of amoA gene reduced by 39.3% in chili soils due to high inputs and increased significantly by 110.8% in black gram soils. β-Glucosidase also increased by 27.2% and 325.0%, respectively. Acid phosphatase activity reduced by 29.2% due to high inputs in chili soils and increased by 105.0% in black gram soils. The use of high agrochemical inputs thus had adverse consequences on biological health in chili but not in black gram soils. In soils cultivated with black gram, the moderating effect of cultivating legumes and their beneficial effect on soil health were evident from the increase in soil labile carbon, lower qMLC, higher amoA gene and enzyme activities. Overall results showed that cultivation of legumes permits intensive chemical farming without deteriorating soil biological health.