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.

Cultivation and characterization of the bacterial assemblage of epsomic Basque Lake, BC.

Athalassohaline waters that are rich in divalent ions are good analogues for the chemical environments of Mars and the ocean worlds. Sulfate salts, along with chlorides, are important in Mars regolith with Ca, Fe, Mg, and Na counterions. Certain lakes in the Pacific Northwest are saturated with MgSO as epsomite.

Nitrogen-fixation activity and the abundance and taxonomy of nifH genes in agricultural, pristine, and urban prairie stream sediments chronically exposed to different levels of nitrogen loading.

Small streams exert great influences on the retention and attenuation of nitrogen (N) within stream networks. Human land use can lead to increased transport of dissolved inorganic N compounds and downstream eutrophication. Microbial activity in streams is important for maintaining an actively functioning N cycle.

Prevalence of sucretolerant bacteria in common soils and their isolation and characterization.

Sucretolerant microbes grow in the presence of sugar concentrations high enough to substantially lower water activities. Natural habitats high in sugars are mainly limited to dried fruit, floral nectar, honey, sugarcane, and associated soils. Organisms that tolerate extremes of solute concentration, high enough to lower water activities, might not be expected in common oligoosmotic soils.

Isolation and Characterization of Halotolerant Soil Fungi from the Great Salt Plains of Oklahoma.

The Great Salt Plains (GSP) of Oklahoma is an inland terrestrial hypersaline environment where saturated brines leave evaporite crusts of NaCl. The current report examines the fungal community, complementing earlier reports on the bacterial and archaeal communities. Twenty-five fungal isolates from GSP soils were obtained on medium containing 10% NaCl and characterized.

Molecular and Phenetic Characterization of the Bacterial Assemblage of Hot Lake, WA, an Environment with High Concentrations of Magnesium Sulfate, and Its Relevance to Mars.

Hot Lake (Oroville, WA) is an athalassohaline epsomite lake that can have precipitating concentrations of MgSO salts, mainly epsomite. Little biotic study has been done on epsomite lakes and it was unclear whether microbes isolated from epsomite lakes and their margins would fall within recognized halotolerant genera, common soil genera, or novel phyla. Our initial study cultivated and characterized epsotolerant bacteria from the lake and its margins.

Comparative molecular analysis of the prokaryotic diversity of two salt mine soils in southwest China.

While much is known about the microbial diversity in some hypersaline environments, little is known about those of salt mine tunnel soils. The objective of this study was to conduct a comprehensive phylogenetic comparison of the archaeal and bacterial communities present in Yipinglang salt mine (YPL) and Qiaohou salt mine (QH) tunnels differing in salinity and salt composition using 16S rRNA gene clone libraries. Two hundred twenty-eight sequences for QH and 182 sequences for YPL were analyzed by amplified ribosomal DNA-restriction analysis.

Colorimetric microbial diversity analysis and halotolerance along a soil salinity gradient at the Great Salt Plains of Oklahoma.

Microbial diversity was measured along a salinity gradient at the Great Salt Plains of Oklahoma using colony color quantified as RGB components of microbial isolate streaks. Numerical taxonomy was performed using a UPGMA method to create trees of relatedness, define OTUs, and calculate diversity indices. Surface soil samples along a 6-m salinity gradient (from hypersaline soil with 7.

Inexpensive and safe DNA gel electrophoresis using household materials.

Gel electrophoresis is the single most important molecular biology technique and it is central to life sciences research, but it is often too expensive for the secondary science classroom or homeschoolers. A simple safe low-cost procedure is described here that uses household materials to construct and run DNA gel electrophoresis. Plastic containers are fitted with aluminum foil electrodes and 9-V batteries to run food-grade agar-agar gels using aquarium pH buffers and then stained with gentian violet.

Bacterial growth at the high concentrations of magnesium sulfate found in martian soils.

The martian surface environment exhibits extremes of salinity, temperature, desiccation, and radiation that would make it difficult for terrestrial microbes to survive. Recent evidence suggests that martian soils contain high concentrations of MgSO₄ minerals. Through warming of the soils, meltwater derived from subterranean ice-rich regolith may exist for an extended period of time and thus allow the propagation of terrestrial microbes and create significant bioburden at the near surface of Mars.

Culture-independent analysis of the soil bacterial assemblage at the Great Salt Plains of Oklahoma.

The Great Salt Plains (GSP) of Oklahoma is a natural inland terrestrial hypersaline environment that forms evaporite crusts of mainly NaCl. Previous work described GSP bacterial assemblages through the phylogenetic and phenetic characterization of 105 isolates from 46 phylotypes. The current report describes the same bacterial assemblages through culture-independent 16S rRNA gene clone libraries.

Archaeal diversity at the great salt plains of Oklahoma described by cultivation and molecular analyses.

The Great Salt Plains of Oklahoma is a natural inland terrestrial hypersaline environment that forms evaporite crusts of mainly NaCl. Previous work described the bacterial community through the characterization of 105 isolates from 46 phylotypes. The current report describes the archaeal community through both microbial isolation and culture-independent techniques.

West Nile virus antibodies in permanent resident and overwintering migrant birds in south-central Kansas.

Unlabelled: We conducted serological studies, using epitope-blocking ELISAs directed at West Nile virus (WNV) and flavivirus antibodies, of wild birds in south-central Kansas, the first for this state, in the winters of 2003-04 through 2005-06. Overwintering migratory species (primarily the American tree sparrow and dark-eyed junco) consistently showed significantly lower seropositivity than permanent residents (primarily the northern cardinal). The cardinal showed annual variation in seropositivity between winters.

Carbon substrate utilization, antibiotic sensitivity, and numerical taxonomy of bacterial isolates from the Great Salt Plains of Oklahoma.

The current work extends the phenotypic characterization of a bacterial culture collection from the Great Salt Plains of Oklahoma. This barren expanse of mud flats is typically crusted with thalassohaline salt evaporites. The initial account of the aerobic heterotrophic bacteria from the Great Salt Plains described 105 halotolerant isolates that represented 47 phylotypes.

Delta-aminolevulinic acid biosynthesis in Ustilago maydis.

A biosynthetic precursor of tetrapyrroles, delta-aminolevulinic acid (ALA), can be formed via two pathways: enzymatic condensation of glycine and succinyl-CoA by ALA synthase in animal mitochondria and some fungi, and the C5 pathway converting glutamate to ALA in plants, algae, archaea, and most bacteria. The two pathways are distinguishable using specifically radiolabeled compounds. The C1 of glutamate is lost during conversion to succinate in the TCA cycle, and the C2 of glycine is lost during conversion to acetyl-CoA on the way to glutamate.

DNA-repair potential of Halomonas spp. from the Salt Plains Microbial Observatory of Oklahoma.

The Great Salt Plains (GSP), an unvegetated, barren salt flat that is part of the Salt Plains National Wildlife Refuge near Cherokee, Oklahoma, is the site of the Salt Plains Microbial Observatory. At the GSP the briny remains of an ancient sea rise to the surface, evaporate under dry conditions, and leave crusts of white salt. Adaptation to this environment requires development of coping mechanisms providing tolerance to desiccating conditions due to the high salinity, extreme temperatures, alkaline pH, unrelenting exposure to solar UV radiation, and prevailing winds.

Halotolerant aerobic heterotrophic bacteria from the Great Salt Plains of Oklahoma.

The Salt Plains National Wildlife Refuge (SPNWR) near Cherokee, Oklahoma, contains a barren salt flat where Permian brine rises to the surface and evaporates under dry conditions to leave a crust of white salt. Rainfall events dissolve the salt crust and create ephemeral streams and ponds. The rapidly changing salinity and high surface temperatures, salinity, and UV exposure make this an extreme environment.

Elemental and redox analysis of single bacterial cells by x-ray microbeam analysis.

High-energy x-ray fluorescence measurements were used to make elemental maps and qualitative chemical analyses of individual Pseudomonas fluorescens strain NCIMB 11764 cells. Marked differences between planktonic and adhered cells were seen in the morphology, elemental composition, and sensitivity to Cr(VI) of hydrated cells at spatial scales of 150 nm. This technology can be applied to natural geomicrobiological systems.

Direct extraction of DNA from soils for studies in microbial ecology.

Molecular analyses for the study of soil microbial communities often depend on the extraction of DNA directly from soils. These extractions are by no means trivial, being complicated by humic substances that are inhibitory to PCR and restriction enzymes or being too highly colored for blot hybridization protocols. Many different published protocols exist, but none have been found to be suitable enough to be generally accepted as a standard.

Biomass byproducts for the remediation of wastewaters contaminated with toxic metals.

Pollution of the environment with toxic metals is widespread and often involves large volumes of wastewater. Remediation strategies must be designed to support high throughput while keeping costs to a minimum. Biosorption is presented as an alternative to traditional physicochemical means for removing toxic metals from wastewater.