The broad antibacterial activity of a small synthetic receptor for cellular phosphatidylglycerol lipids.

A small receptor molecule composed of a porphyrin core with tetrakis-ammonium glycine pickets (liptin 3e) appears to target anionic phosphatidylglycerol (PG) lipid head groups through multifunctional binding-pocket complementarity. Although a major component of bacterial cell membranes, PG is not widely found in animal cells, making PG potentially selective for bacterial targeting. Growth of microbial isolates was monitored in liquid cultures treated with liptin 3e by dilution plate counts and turbidity.

Bacterial Growth in Brines Formed by the Deliquescence of Salts Relevant to Cold Arid Worlds.

Hygroscopic salts at Mars' near-surface (MgSO, (per)chlorates, NaCl) may form brines by absorbing moisture from the atmosphere at certain times through the process of deliquescence. We have previously shown strong bacterial growth in saturated MgSO (∼67% w/v as epsomite) at room temperature, and growth was observed at the MgSO eutectic point (43% w/v at -4°C). Here, we have investigated the growth of salinotolerant microbes () from Hot Lake, Washington; Basque Lake, British Columbia; and Great Salt Plains, Oklahoma under deliquescing conditions.

Effects of Nitrogen and Phosphorus Limitation on Lipid Accumulation by str. UTEX 263 Grown in Darkness.

Growing algae in darkness for biodiesel production eliminates the challenges of evaporation and light penetration reported for open ponds and the costs and fouling that plague photobioreactors. The current study demonstrated that str. UTEX 263 could grow heterotrophically in the dark on pure sugars or lignocellulosic hydrolysates of plant biomass.

Mars Extant Life: What's Next? Conference Report.

On November 5-8, 2019, the "Mars Extant Life: What's Next?" conference was convened in Carlsbad, New Mexico. The conference gathered a community of actively publishing experts in disciplines related to habitability and astrobiology. Primary conclusions are as follows: A significant subset of conference attendees concluded that there is a realistic possibility that Mars hosts indigenous microbial life.

Bacterial Growth in Saturated and Eutectic Solutions of Magnesium Sulphate and Potassium Chlorate with Relevance to Mars and the Ocean Worlds.

Liquid water on Mars might be created by deliquescence of hygroscopic salts or by permafrost melts, both potentially forming saturated brines. Freezing point depression allows these heavy brines to remain liquid in the near-surface environment for extended periods, perhaps as eutectic solutions, at the lowest temperatures and highest salt concentrations where ices and precipitates do not form. Perchlorate and chlorate salts and iron sulfate form brines with low eutectic temperatures and may persist under Mars near-surface conditions, but are chemically harsh at high concentrations and were expected to be incompatible with life, while brines of common sulfate salts on Mars may be more suitable for microbial growth.