I consider how cell shape and environmental geometry affect the rate of nutrient capture and the consequent maximum growth rate of a cell, focusing on rod-like species like E. coli. Simple modeling immediately implies that it is the elongated profiles of such cells that allows for them to grow – as observed – at exponential rates in nutrient-rich media. Growth is strongly suppressed when nutrie...

A mathematical model was developed and used to simulate the long-term dynamics of growth and plasmid transfer in nutrient-limited soil microcosms of Streptomyces lividans TK24 carrying chromosomal resistance to streptomycin, S. lividans 1326; and S. violaceolatus ISP5438. Donor, recipient, and transconjugant survival was modelled by an extension to the Verhulst logistic equation which takes acc...

Recent experiments for swarming of the bacteria Bacillus subtilis on nutrient rich media show that these cells are able to proliferate and spread out in colonies exhibiting complex patterns as dendritic ramifications. Is it possible to explain this process with a model that does not use local nutrient depletion? We present a new class of models which is compatible with the experimental observat...

Abstract Background and Objectives Proliferation and differentiation of mesenchymal stem cells (MSCs) in culture media requires the presence of nutrient supplements such as bovine fetal serum (FBS), which increases the risk of prion/xenotic infections. Platelet lysates as a rich source of growth factors and cytokines can replace FBS in cell culture medium. This study aimed to compare the effe...

Allelopathy can play an important role in structuring plant communities, but allelopathic effects are often difficult to detect because many methods used to test for allelopathy can be confounded by experimental artifacts. The use of activated carbon, a technique for neutralizing allelopathic compounds, is now employed in tests for allelopathy; however, this technique also could produce large e...

The present study evaluated the effects of the culturing media and the levels of nitrogen and phosphorus on the growth, biomass productivity and lipid production of four species of Microcystis (M. novacekii, M. aeruginosa, M panniformis and M. protocystis). The lipid extract was obtained by refluxing with dichloromethane (Soxhlet). The biomass and biomass productivity yields were maximized with...

A streptomycin-resistant variant of Xanthomonas campestris was grown in defined nutrient-deficient media in both batch and continuous culture. The production, composition and viscosity of the extracellular polysaccharide (xanthan) synthesized by this strain were influenced by the fermentation time and nutrient exhaustion in batch culture and by the dilution rate in continuous culture. The speci...

The aim of this study was to evaluate the survival responses of two strains of Vibrio splendidus, both in natural and in defined media. For this purpose, freshwater and defined media containing different salinities (3.3-0.9 %) and nutrient concentrations (17-0.005 mg x l(-1)) were assayed. The incubation temperatures were established at 4, 10 and 22 degrees C. The acridine orange staining techn...

in order to investigate the possibility of using organic fertilizers in tobacco floating nursery, an experiment was conducted at tobacco research institute of urmia in 2010. the experiment was done as factorial trail based on randomized complete block design (crbd) with four replications. the levels of first factor were disinfected poultry manure, disinfected pigeon manure, a complete fertilize...

In conventional wastewater treatment, biological nutrient removal (BNR) depends on bacterial assimilation for phosphorus removal and nitrification+denitrification for nitrogen removal, with the resulting loss of the fixed nitrogen resource. Alternatively, treatment by microalgae allows for assimilative removal of both phosphorus (P) and nitrogen (N) thereby avoiding the oxygen demand of nitrifi...