Application of time-series regularity metrics to ion flux data from a population of pollen tubes.

Detecting the presence of an irregularity/regularity or chaos in the ion flows of an evolving plant cell is an important task that can be unraveled by performing the analyses by different metrics. Here I show that the results of the advanced fluctuation estimation methods that are obtained from the time series that is generated by the extracellular ion fluxes of tobacco pollen tubes (Nicotiana tabacum L.) have long-range correlations at critical temperatures. Further experimental evidence has been found to support the claim that the autonomous growth organization of extreme plant cell expansion is accomplished by self-organizing criticality (SOC), which is an orchestrated instability that occurs in an optimally evolving cell. The temperature-induced synchronous action of the ionic fluxes that are manifested, inter alia, by minimal dynamic entropy enabled the molecularly encoded information about germination and optimal growth temperatures of tobacco pollen tubes to be determined.

Extracellular ionic fluxes suggest the basis for cellular life at the 1/f ridge of extended criticality.

The criticality hypothesis states that a system may be poised in a critical state at the boundary between different types of dynamics. Previous studies have suggested that criticality has been evolutionarily selected, and examples have been found in cortical cell cultures and in the human nervous system. However, no one has yet reported a single- or multi-cell ensemble that was investigated ex vivo and found to be in the critical state. Here, the precise 1/f noise was found for pollen tube cells of optimum growth and for the physiological ("healthy") state of blood cells. We show that the multi-scale processes that arise from the so-called critical phenomena can be a fundamental property of a living cell. Our results reveal that cell life is conducted at the border between order and disorder, and that the dynamics themselves drive a system towards a critical state. Moreover, a temperature-driven re-entrant state transition, manifest in the form of a Lorentz resonance, was found in the fluctuation amplitude of the extracellular ionic fluxes for the ensemble of elongating pollen tubes of Nicotiana tabacum L. or Hyacintus orientalis L. Since this system is fine-tuned for rapid expansion to reach the ovule at a critical temperature which results in fertilisation, the core nature of criticality (long-range coherence) offers an explanation for its potential in cell growth. We suggest that the autonomous organisation of expansive growth is accomplished by self-organised criticality, which is an orchestrated instability that occurs in an evolving cell.

Response of Natural Cyanobacteria and Algae Assemblages to a Nutrient Pulse and Elevated Temperature.

Eutrophication (nutrient over-enrichment) is the primary worldwide water quality issue often leading to nuisance cyanobacterial blooms. Climate change is predicted to cause further rise of cyanobacteria blooms as cyanobacteria can have a competitive advantage at elevated temperatures. We tested the hypothesis that simultaneous rise in nutrients and temperature will promote cyanobacteria more than a single increase in one of the two drivers. To this end, controlled experiments were run with seston from 39 different urban water bodies varying in trophic state from mesotrophic to hypertrophic. These experiments were carried out at two different temperatures, 20°C (ambient) and 25°C (warming scenario) with or without the addition of a surplus of nutrients (eutrophication scenario). To facilitate comparisons, we quantified the effect size of the different treatments, using cyanobacterial and algal chlorophyll a concentrations as a response variable. Cyanobacterial and algal chlorophyll a concentrations were determined with a PHYTO-PAM phytoplankton analyzer. Warming caused an 18% increase in cyanobacterial chlorophyll-a, while algal chlorophyll-a concentrations were on average 8% higher at 25°C than at 20°C. A nutrient pulse had a much stronger effect on chlorophyll-a concentrations than warming. Cyanobacterial chlorophyll-a concentrations in nutrient enriched incubations at 20 or 25°C were similar and 9 times higher than in the incubations without nutrient pulse. Likewise, algal chlorophyll-a concentrations were 6 times higher. The results of this study confirm that warming alone yields marginally higher cyanobacteria chlorophyll-a concentrations, yet that a pulse of additional nutrients is boosting blooms. The responses of seston originating from mesotrophic waters seemed less strong than those from eutrophic waters, which indicates that nutrient control strategies -catchment as well as in-system measures- could increase the resilience of surface waters to the negative effects of climate change.

Optimización del medio de cultivo QBP para la producción de biomasa del consorcio BIOYAF / Optimization of culture media QBP to the production of biomass of consortium BIOYAF

La optimización de los medios de cultivo con fines industriales en la mayoría de los casos ha sido efectuada mediante procedimientos empíricos de ensayo y error. Empleando diversos métodos estadísticos es probable que el medio de cultivo original pueda ser optimizado, en muchos casos es posible obtener un medio que no solo sea más productivo, sino de menor o igual costo que el original. Se optimizó el medio de cultivo QBP para el crecimiento de las cepas del consorcio bacteriano BIOYAF capaz de degradar hidrocarburos del petróleo, empleando un Diseño de Factor Categórico Individual para determinar el tiempo de trabajo, un Diseño Factorial (24) para determinar los rangos de trabajo de concentración de los nutrientes y un Diseño de Superficie de Respuesta para optimizar las concentraciones. Las variables de respuesta de evaluación de los experimentos fueron masa húmeda, masa (UDO), conteo de viables, conductividad, pH y tensión superficial. El tiempo óptimo para el crecimiento de las cepas del consorcio BIOYAF es de seis horas. El medio de cultivo QBP con concentraciones óptimas de fosfato de amonio (3,19 g.L-1), sulfato de magnesio (0,04 g.L-1), levadura (3,77 g.L-1) y sacarosa (47,89 g.L-1) permite que la producción de biomasa aumente de 1,540 UDO a 3,082 UDO.

The optimization of culture media with industrial purposes, in most cases, has been made through empirical trial and error procedures. Using different statistical methods original culture media can be optimized, in many cases, is possible to obtain a more productive media, at the same cost as the original one. The culture media QBP was optimized for the growth of the bacterial consortium BIOYAF, which can degrade petroleum hydrocarbons, using a Categorical Individual Factor Design to determine the working time, a Factorial Design (24) to determine working range of elements concentration and a Surface Response Design to optimize the concentrations. The response variables of the experiments used in this work were: wet mass, mass (UDO), viable's count, conductivity, pH and surface tension. The optimal time for growth of the consortium was of six hours. The optimized QBP culture media (ammonium phosphate: 3.19; magnesium sulphate: 0,04; yeast extract : 3,77; sucrose: 47,89) allowed that the biomass' production increases of 1,540 UDO to 3,082 UDO.

Comparison of simple sequence repeats in 19 Archaea

All organisms that have been studied until now have been found to have differential distribution of simple sequence repeats (SSRs), with more SSRs in intergenic than in coding sequences. SSR distribution was investigated in Archaea genomes where complete chromosome sequences of 19 Archaea were analyzed with the program SPUTNIK to find di- to penta-nucleotide repeats. The number of repeats was determined for the complete chromosome sequences and for the coding and non-coding sequences. Different from what has been found for other groups of organisms, there is an abundance of SSRs in coding regions of the genome of some Archaea. Dinucleotide repeats were rare and CG repeats were found in only two Archaea. In general, trinucleotide repeats are the most abundant SSR motifs; however, pentanucleotide repeats are abundant in some Archaea. Some of the tetranucleotide and pentanucleotide repeat motifs are organism specific. In general, repeats are short and CG-rich repeats are present in Archaea having a CG-rich genome. Among the 19 Archaea, SSR density was not correlated with genome size or with optimum growth temperature. Pentanucleotide density had an inverse correlation with the CG content of the genome.