[en] Evolution to multicellularity from an aggregate of cells involves altruistic cooperation between individual cells, which is in conflict with Darwinian evolution. How cooperation arises and how a cell community resolves such conflicts remains unclear. In this study, we investigated the spontaneous emergence of cell differentiation and the subsequent division of labour in evolving cellular metabolic networks. In spatially extended cell aggregates, our findings reveal that resource limitation can lead to the formation of subpopulations and cooperation of cells, and hence multicellular communities. A specific example of our model can explain the recently observed oscillatory growth in Bacillus subtilis biofilms. (paper)

[en] During the present studies, compost-inhabiting microorganisms including 44 fungi and 15 bacteria isolated from different compost samples were evaluated for their in vitro efficacy against soil-borne pathogens viz., Fusarium solani, Macrophomina phaseolina, Pythium aphanidermatum, Rhizoctonia solani, and Sclerotium rolfsii. Compost inhabiting microbes like Trichoderma harzianum, T. virens, Bacillus cereus, B. pumilus, B. subtilis, Micrococcus varians and Pseudomonas fluorescens were found to inhibit all the test pathogens. Acrophialophora fusispora and Penicillium citrinum reduced the mycelial growth of all the test pathogens except Sclerotium rolfsii. Bacillus licheniformis and Bacillus megaterium showed biocontrol activity against all the pathogens except Rhizoctonia solani. Trichoderma harzianum parasitized mycelia of all the tested pathogens and produced coiling around the mycelium. (author)

[en] Bacillus megaterium as a companion strain in two-stage fermentation of vitamin C could secrete some active substances to spur growth of Gluconobacter oxydans to produce 2-KLG. In the fermenting system where Gluconobacter oxydans was combined with GB82-a mutated strain of B. megaterium by ion implantation, the amount of 2-KLG harvested was larger than that produced by the original B. megaterium BP52 being substituted for GB82. In this paper, authors studied the effect of the active substances secreted by GB82 to enhance the capability of Gluconobacter oxydans to produce 2-KLG. The supernate of GB82 sampled at different cultivation times all had much more activity to spur Gluconobacter oxydans to yield 2-KLG than that of the original B. megaterium, which might be due to the genetic changes in the active components caused by ion implantation. Furthermore, the active substances of GB82's supernate would lose a part of its activity in extreme environments, which is typical of some proteins

[en] The effect of temperature, pH and metal ions on the activity and stability of crude protease from Bacillus licheniformis MZK03 was studied. The fermentation in shake culture revealed that maximum level of enzyme was produced at 37 degree C and pH 8.5 after 39 hr at 120 rpm. It lost its activity rapidly above 50 degree C and half-life of the protease at this temperature was 50 min with optimum activity at 40 degree C. It was most stable at pH 8.5 and lost its activity rapidly above pH 10.0, and at pH 11.0 reached 30% of the activity obtained at pH 9.0. The enzyme lost its activity completely at pH 13.0. Optimum proteolytic activity was found at 40 degree C and pH 9.5. The enzyme activity was accelerated by the addition of Mg/sup 2+/, Ca/sup 2+/ and Mn/sup 2+/, whereas it was inhibited by Hg/sup 2+/. (author)

[en] The swimming of a bacterium in fluids occurs in a low Reynolds number regime. The ability to confine the swimming motion by trapping a bacterium in laser light, can give information on the propulsion coefficients, which are important in explaining the efficiency of swimming of these bacteria. In this work, we report the results of an optically trapped Bacillus subtilis in an optical tweezer and the studies on the rotatory motion of the bacterium. The data is gathered and analysed using video microscopy. The propulsion coefficients of such swimming bacterium are determined through a power spectral analysis of the rotatory motion of the bacterium in the trap. (paper)

[en] The initial bioburden or count of colony forming unit (CFU) were determined on the locally manufactured non-sterilized sanitary pads and Sterilization Dose (SD) and Device Verification Dose (DVD) calculations were done. A total of 180 tests were carried out on sixty samples. The maximum and minimum microbial contaminants found were 248 and 92 respectively with an average of 175. The 20% samples were subjected to identification, only aerobic microorganisms were isolated and identified as bacilli. Most of the isolates (83%) were Bacillus pumilus and subtillis. The Sterilization Dose (SD) calculated by the method proposed by Sterilization Standards Committee, Association of the Advancement of Medical Instrumentation (AAMI), for a Sterility Assurance Level (SAL) of 10/sup -3/ set for this item was 1.18 Mrads whereas Device Verification Dose (DVD) was 0.59 Mrads. (author)

[en] The germicidal effects of a non-equilibrium atmospheric pressure plasma generated by a novel resistive barrier discharge on representatives of the two classes of bacteria (Gram-negative and Gram-positive) are discussed. The plasma exposure, while being lethal to both bacterial classes, also produced gross structural damage in the Gram-negative E. coli while none was observed in the more structurally robust Gram-positive Bacillus subtilis. An electrophysical process involving the role of the electrostatic tension on a charged body in a plasma is invoked to explain both observations. Since the efficacy of this electrophysical process depends not only on the tensile strength of the bacterial cell wall but also on its shape and texture, the need for more experimental studies, using a wide range of bacteria belonging to various morphological groups, is suggested. Ways to further test the validity of this electrophysical lysis mechanism for Gram-negative bacteria on one hand, and also to extend its operation to the more robust Gram-positive bacteria on the other, are suggested

[en] Bacillus Cereus is an opportunistic pathogen. It is a causative agent in both gastrointestinal and in non gastrointestinal infections. In this study, 41 strains of Bacillus Cereus were isolated on Polymixin-Mannitol-Egg-Yolk Phenol red Agar (PMYPA) from foods (milk products, pasta, meat). These isolates were characterised and identified by biochemical and molecular tests. Pcr was performed for detection and characterisation of toxins genes in bacillus cereus. (author). 108 refs

[en] A short summary of the main topics and developments of microbial leaching methods with thiobacilli and heterotrophic (chemorganotrophic) fungi and bacteria during the last 4 years is given. (orig.)

[en] The capacity to solubilize phosphate and to produce indole compounds Indole Acetic Acid type, was evaluated in 15 strains isolated from castor bean lignocellulosic residues (Ricinus communis). To determine the solubilizing activity of phosphates a qualitative test by using Pikovskaya culture medium was employed and for the evaluation of the production of indole compounds (IAA) a Salkowsky colorimetric analysis technique was applied. Among the microorganisms tested, the Bacillus pumilus GIBI 206 demonstrated capacity to solubilize phosphates and Bacillus subtilis GIBI 200 showed of capacity to solubilize phosphates and to produce Indoleacetic Acid (IAA). To determine the effect of the Bacillus subtilis strain on germination and growth promotion, tomato seeds (Solanum lycopersicum Santa Clara) were inoculated; the inoculation of the seeds along with the microorganism revealed statistically significant differences, during the germination stage compared to the control treatment. Nevertheless, it revealed a positive influence on the development of tomato plants, originating a significant increase on the mass and length of its stem and root. The results of this research offer the possibility of using the Bacillus subtilis as a growth promoter in tomato seedlings and in the formulation of bio-products.