Microorganisms

Background and objectives: Increasing the use of chemical fertilizers in order to increase yield can over time have adverse effects on soil and environment and the reduction of consumption of these fertilizers in sustainable agriculture is necessary. EM contains selected species of microorganisms, including dominant populations of lactic acid bacteria and yeasts, and a small number of photosynthetic bacteria, octanomists that are compatible with each other. These microorganisms improve soil structure, manage organic matter and complete the cycle of elements, and can reduce dependence on fertilizers and chemical pesticides. The increase of protein activity and plant photosynthesis capacity, plant growth, root development, flowering, fruit harvesting, and the improvement of food availability and its better absorption by the plant are due to the benefits of using this biological fertilizer. The aim of this study was to investigate the effects of nitrogen application with Urea fertilizer source and bio-fertilizer EM on nutrient uptake by leaf and yield of strawberry Parous cultivar.
Materials and methods: This experiment was carried out as split plot based on randomized complete block design with three replications at the University of Mohaghegh Ardebili University during the years 2016-2015. Treatments consisted of nitrogen as urea fertilizer at three levels (50, 100 and 150 kg.ha-1 pure nitrogen) and EM bio-fertilizer using two methods of application (foliar and soil with irrigation water) at concentrations of 0, 1, 2 and 3%. In this research, the elements of nitrogen, potassium, phosphorus, sodium, magnesium, calcium, manganese, magnesium and iron of leaves and fruit yield were measured.
Results: According to the results, application of EM fertilizer had a significant and positive effect on all measured traits. The 2% EM treatment with the highest concentration was 2.04% and the control plants had the least leaf nitrogen content with 1.42%. The highest amount of phosphorus was obtained with 1.99, 1.93 and 1.67 mg.kg-1, respectively, with 2, 1 and 3% treatments and the leaves of control plants with the lowest content of 26.2 mg.kg-1 of phosphorus were lowest. The amount of potassium at 1% level was 46.18 at 2 level 45.95 and 44.86 mg.kg-1 in 3%, which was in a statistical group and the control plants had the least amount of potassium. The same trend was observed in the elements of calcium, iron, zinc and manganese. The highest fruit yield was obtained in plants treated with 2% and 3% EM (respectively 185.2 and 176.75 g per plant, respectively). Plants leave Nitrogen content treated with 150 kg of urea fertilizer was 2.9% higher than other concentrations. The amount of potassium, phosphorus, zinc and manganese in leaf and yield of plants treated with 100 kg.ha-1 was higher than other levels of urea fertilizer. Based on the results of the comparison of averages, the application of urea crop 100 kg.ha-1 with EM and 2 and 3% respectively with 141 and 139 mg.kg-1 produced the highest amount of magnesium in the leave.

Conclusion: Generally, it can be concluded that application of EM bio-fertilizer with both spraying and soil methods can improve plant growth, yield and nutrient uptake by roots of strawberries. The best and the most suitable nitrogen concentration in terms of fruit yield and leaf elements were 100 kg / ha.

We propose a dynamics model of galvanotaxis (locomotor response to electrical stimulus) of the protozoan Paramecium. Our purpose is to utilize microorganisms as micro- robots by using galvanotaxis. For precise and advanced actuation, it is necessary to describe the dynamics of galvanotaxis in a mathematical and quantitative manner in the framework of robotics. However, until now the explanation of Paramecium galvanotaxis in previous works has remained only qualitative. In this paper, we construct a novel model of galvanotaxis as a minimal step to utilizing Paramecium cells as micro-robots. Numerical experiments for our model demonstrate realistic behaviors, such as U-turn motions, like those of real cells. Index Terms—Paramecium, galvanotaxis, dynamics, model, microrobot

Quantitative polymerase chain reaction Extraction efficiency Water Microbial source tracking a b s t r a c t Quantitative PCR (qPCR), applied to complex environmental samples such as water, wastewater, and feces, is susceptible to methodological and sample related biases. In this study, we evaluated two exogenous DNA spike-and-recovery controls as proxies for recovery efficiency of Bacteroidales 16S rDNA gene sequences (AllBac and qHF183) that are used for microbial source tracking (MST) in river water. Two controlsd(1) the plant pathogen Pantoea stewartii, carrying the chromosomal target gene cpsD, and (2) Escherichia coli, carrying the plasmid-borne target gene DsRed2dwere added to raw water samples immediately prior to concentration and DNA extraction for qPCR. When applied to samples processed in replicate, recovery of each control was positively correlated with the observed concentration of each MST marker. Adjustment of MST marker concentrations according to recovery efficiency reduced variability in replicate analyses when consistent processing and extraction methodologies were applied. Although the effects of this procedure on accuracy could not be tested due to uncertainties in control DNA concentrations, the observed reduction in variability should improve the strength of statistical comparisons.

Traditional smoked fermented sausages are highly appreciated in Portugal and are mostly manufactured according to traditional procedures. The aim of the present work was to evaluate the effect of autochthonous starter cultures on the safety and quality of a smoked fermented sausage, Painho da Beira Baixa (PBB), preserving its sensory quality. Physicochemical parameters, namely pH and water activity (aW), microbiological parameters, biogenic amines, colour, texture profile and sensory attributes were assessed. Different starters were selected based on our previous work. Staphylococcus equorum S2M7, Staphylococcus xylosus CECT7057, Lactobacillus sakei CV3C2, Lactobacillus sakei CECT7056 and a yeast strain (2RB4) were co-inoculated in meat batters at defined concentrations. Starters had a significant effect on the reduction of pH. Enterobacteria and Listeria monocytogenes were not detected in inoculated end-product sausages. Moreover, sausages inoculated with S. equorum S2M7/L. sakei C...

Nitrogen fixation, a prokaryotic, O 2 -inhibited process that reduces N 2 gas to biomass, is of paramount importance in biogeochemical cycling of nitrogen. We analyzed the levels of nif transcripts of Synechococcus ecotypes, NifH subunit and nitrogenase activity over the diel cycle in the microbial mat of an alkaline hot spring in Yellowstone National Park. The results showed a rise in nif transcripts in the evening, with a subsequent decline over the course of the night. In contrast, immunological data demonstrated that the level of the NifH polypeptide remained stable during the night, and only declined when the mat became oxic in the morning. Nitrogenase activity was low throughout the night; however, it exhibited two peaks, a small one in the evening and a large one in the early morning, when light began to stimulate cyanobacterial photosynthetic activity, but O 2 consumption by respiration still exceeded the rate of O 2 evolution. Once the irradiance increased to the point at which the mat became oxic, the nitrogenase activity was strongly inhibited. Transcripts for proteins associated with energy-producing metabolisms in the cell also followed diel patterns, with fermentation-related transcripts accumulating at night, photosynthesis-and respiration-related transcripts accumulating during the day and late afternoon, respectively. These results are discussed with respect to the energetics and regulation of N 2 fixation in hot spring mats and factors that can markedly influence the extent of N 2 fixation over the diel cycle.

The genus Veillonella is a common and abundant member of the oral microbiome. It includes eight species, V. atypica, V. denticariosi, V. dispar, V. infantium, V. nakazawae, V. parvula, V. rogosae and V. tobetusensis. They possess important metabolic pathways that utilize lactate as an energy source. However, the overall metabolome of these species has not been studied. To further understand the metabolic framework of Veillonella in the human oral microbiome, we conducted a comparative pan-genome analysis of the eight species of oral Veillonella. Analysis of the oral Veillonella pan-genome revealed features based on KEGG pathway information to adapt to the oral environment. We found that the fructose metabolic pathway was conserved in all oral Veillonella species, and oral Veillonella have conserved pathways that utilize carbohydrates other than lactate as an energy source. This discovery may help to better understand the metabolic network among oral microbiomes and will provide guid...