Comparing vector–host and SIR models for dengue transmission

Various simple mathematical models have been used to investigate dengue transmission. Some of these models explicitly model the mosquito population, while others model the mosquitoes implicitly in the transmission term. We study the impact of modeling assumptions on the dynamics of dengue in Thailand by fitting dengue hemorrhagic fever (DHF) data to simple vector–host and SIR models using Bayesian Markov chain Monte Carlo estimation. The parameter estimates obtained for both models were consistent with previous studies. Most importantly, model selection found that the SIR model was substantially better than the vector–host model for the DHF data from Thailand. Therefore, explicitly incorporating the mosquito population may not be necessary in modeling dengue transmission for some populations.     

Study of Surface Enhanced Raman Scattering of Single Molecule Adsorbed on the Surface of Metal Nanogeometries: Electrostatic Approach

Plasmonics - In this paper, we have studied the surface enhanced raman scattering (SERS) from a molecule adsorbed on coated and non-coated spherical shape metallic nanoparticles. We have accounted...     

Endophytes of opium poppy differentially modulate host plant productivity and genes for the biosynthetic pathway of benzylisoquinoline alkaloids

Planta - Endophytes reside in different parts of the poppy plant and perform the tissue-specific functions. Most leaf endophytes modulate photosynthetic efficiency, plant growth, and productivity...     

Rare medicinal herbs of the Himalayas: an ardent need for preservation

The forest wealth of the Himalayan ranges is abundant with unique medicinal herbs, having tremendous economic importance. Latterly, these have adversely suffered at the hands of poachers and unlawful trade activities. The author cites the names of some of the rare species, in a bid to achieve their conservation through sensitization and participation of the masses, especially the tribals, in the greater interest of humanity.     

Correction to: External Supplement of Impulsive Micromanager Trichoderma Helps in Combating CO2 Stress in Rice Grown Under FACE

Plant Molecular Biology Reporter - The original version of this article unfortunately contained missing information at author’s affiliations. The affiliation address of the author’s...     

Immobilization Results in Sustained Calcium Transport in Nostoc calcicola Bréb

The uptake pattern of Ca²⁺ by the cyanobacterium Nostoc calcicola Bréb in its freely suspended and immobilized form is comprised of two distinct phages; (a) rapid uptake for 1^st 10 min followed by (b) slower transport at least up to 60 min. Entrapment of cyanobacterial cells in polyvinyl foam always maintained a higher Ca²⁺ profile over freely suspended cells. Also, the intracellular Ca²⁺ concentration was three times more in the former under similar experimental conditions. Whereas, illumination supported maximum Ca²⁺ transport in all the sets, darkness resulted in drastic reduction (90%) of Ca²⁺ uptake in freely suspended cells and least (15%) in polyvinyl entrapped cyanobacterial cells. Exogenously added ATP (10 μM) on the other hand, enhanced Ca²⁺ uptake in dark incubated freely suspended cells; ATP at the same concentration failed to bring out any significant enhancement in cation uptake in immobilized cells facing dark exposure. It was observed that these cells were still able to sustain sufficient ATP preserves to drive active transport of Ca²⁺ even in the dark. Furthermore, the immobilized cells exhibited remarkable Ca²⁺ transport rate even at the age of 20 and 50 days at which its free living counterpart took up insignificant Ca²⁺. These findings suggest the improved metabolic efficiency of polyvinyl foam entrapped cells over freely suspended cells in terms of Ca²⁺ accumulation and its possible use as a bioreactor for metal accumulation/removal in repetitive cycles without any measurable loss in cell biomass. Received: 21 May 2001 / Accepted: 27 June 2001     

Microbial metabolites as eco-friendly agrochemicals for the next millennium

As a result of the increasing environmental and health-related problems caused by the synthetic agrochemicals currently used, suitable and non-hazardous innovative alternatives are being sought. Antagonism and allelopathy, both in nature and in agro-ecosystems, have attracted these researchers' attention, with the main goal of using these phenomena in the biological control of weeds. This article presents a review on the use and efficacy of microbial secondary metabolites which have potential as natural herbicides, either directly or as templates for bio-rational eco-friendly agrochemicals (allelochemicals). Their merits as alternatives to synthetic chemicals and biological control agents have been highlighted for an holistic approach in integrated pest/weed management.     

Microbial degradation of pyridine and α-picoline using a strain of the genera <Emphasis Type="Italic">Pseudomonas</Emphasis> and <Emphasis Type="Italic">Nocardia</Emphasis> sp.

Biodegradation of pyridine and α-picoline (2-methyl pyridine) by Pseudomonas pseudoalcaligenes-KPN and Nocardia sp. isolated from garden soil were investigated in batch culture experiments. Pyridine and α-picoline (50–200 mg L⁻¹) were used as sole source of carbon and energy in the investigation. The kinetic constants were evaluated for pyridine and α-picoline degradation under optimized nutritional (C, N, P) and environmental (pH, temperature) conditions. The values of bio-kinetic constant obtained in the present investigation indicate the usefulness of both the cultures for treatment of waste containing pyridine and its derivatives.