VOLN27B: A New Head-Tailed Halovirus Isolated from an Underground Salt Crystal and Infecting Halorubrum

A novel halovirus, VOLN27B, was isolated from a drill core sample taken at a depth of approximately 430 m, from a layer formed during the Cretaceous period (Anhui, China). VOLN27B infects the halophilic archaeon Halorubrum sp. LN27 and has a head-tailed morphotype with a contractile tail, typical of myoviruses. The average head diameter is 64 ± 2.0 nm, and uncontracted tails are 15 ± 1.0 × 65 ± 2.0 nm. The latent period is about 10 h. The maturing time of VOLN27B in cells of Halorubrum sp. LN27 was nearly 8 h. The adsorption time of VOLN27B on cells of Halorubrum sp. LN27 was less than 1 min. Virus particles are unstable at pH values less than 5 or when the NaCl concentration is below 12% ( w / v ). VOLN27B and Halorubrum sp. LN27 were recovered from the same hypersaline environment and provide a new virus-host system in haloarchaea.

Biomarker Characterization of Oil Seepages in Tomori Basin, Central Sulawesi, Indonesia

Tomori Basin is located close to the Banggai Basin which has several productive oil fields. Further investigation of the hydrocarbon potential in Tomori Basin is an important issue as potential hydrocarbon resources are indicated by the discovery of several oil seepages in the area. This study identified Tomori Basin oil seepage characteristics using a biomarker analysis approach. The Wosu and Kolo Areas were the main objectives of this study. Oil seepage characteristics were determined using Gas Chromatography (GC) and Gas Chromatography-Mass Spectrometry (GC-MS) methods to generate biomarker data which could be analysed to identify organic matter origin, oxic and anoxic conditions, source facies, or depositional environment. Based on the GC analysis of is oprenoids, the Pristane C19/Phytane C20 ratio (Pr/Ph) of Wosu Oil was 0.75, indicating anoxic conditions typical of a hypersaline environment. Kolo Oil had a Pr/Ph ratio of 3.37 indicative of terrestrial organic input under oxic conditions. A cross plot between Pristane/nC17 and Pr/Ph ratios indicates that Wosu Oil derives from a highly anoxic environment with algae/bacterial organic matter input whereas Kolo Oil derives from a suboxic-oxic environment dominated by terrestrial organic matter input. Trycyclic terpene analysis from C19 to C25 shows Wosu Oil seepages tend to originate from an environment of mixed terrestrial and marine organic matter (transitional environment). Overall, biomarker characteristics indicate that Wosu Oil originated from organic matter in a hypersaline and anoxic environment, whereas Kolo Oil originated from terrestrial matter in a suboxic – oxic environment.

An archaeal histone-like protein regulates gene expression in response to salt stress

Histones, ubiquitous in eukaryotes as DNA-packing proteins, find their evolutionary origins in archaea. Unlike the characterized histone proteins of a number of methanogenic and themophilic archaea, previous research indicated that HpyA, the sole histone encoded in the model halophile Halobacterium salinarum, is not involved in DNA packaging. Instead, it was found to have widespread but subtle effects on gene expression and to maintain wild type cell morphology; however, its precise function remains unclear. Here we use quantitative phenotyping, genetics, and functional genomic to investigate HpyA function. These experiments revealed that HpyA is important for growth and rod-shaped morphology in reduced salinity. HpyA preferentially binds DNA at discrete genomic sites under low salt to regulate expression of ion uptake, particularly iron. HpyA also globally but indirectly activates other ion uptake and nucleotide biosynthesis pathways in a salt-dependent manner. Taken together, these results demonstrate an alternative function for an archaeal histone-like protein as a transcriptional regulator, with its function tuned to the physiological stressors of the hypersaline environment.

Characterization of bioplastics produced by haloarchaeon Haloarcula sp strain NRS20 using cost-effective carbon sources

As good models for developing techniques, Haloarchaea are using as cell factories to produce a considerable concentration of bioplastics, polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), and polyhydroxyvalerate (PHV). In this study, low-cost carbon sources by Sudan Black staining was applied for screening haloarchaea a hypersaline environment (southern coast of Jeddah, Saudi Arabia). The growth of the selected isolate and PHB-production under different carbon sources, temperature, pH values and NaCl concentrations were investigated. The biopolymer was extracted and quantitatively measured. The biopolymer was qualitatively identified by Fourier-transform infra-red analysis (FTIR) and High Performance Liquid Chromatography (HPLC). The potential Haloarcula sp strain NRS20 (MZ520352) could significantly accumulate PHB under nutrient-limiting conditions using different carbon sources including starch, carboxymethyl cellulose (CMC), sucrose, glucose and glycerol with 23.83%, 14%, 11%, 12% and 8% of PHB/CDW respectively under 25% NaCl (w/v), pH 7, at 37 °C. The results of FTIR pattern indicated that the significant peak at 1709.22 cm−1 confirmed the presence of the ester carbonyl-group (C=O) which is typical of PHB. HPLC analysis indicated that produced PHB was detected at 7.5 min with intensity exceeding the standard PHB at 8.0 min. Few potential species of haloarchaea were reported for economical PHB-production, here, Haloarcula sp strain NRS20 showed high content of PHB, exhibited a promising PHB-producer using inexpensive sources of carbon.

GC-mass determination for the biodegradative products of 2,6-dimethylpyridine using Dead-Sea bacterial isolate

Dead sea soil is known for its hypersaline environment and it is a promising location for isolating extremophilic bacteria with interesting metabolic features. In the current study, we isolated a gram-positive bacterium with the ability to degrade 2,6-dimethyl pyridine (2,6-DMP), also known as 2,6-lutidine, a chemical pollutant. The isolated bacteria were identified using the automated Microscan Walkaway system and the different biochemical reactions were determined. In minimal media using the 2,6-DMP as a sole carbon source, the bacterial isolate showed the ability to convert approximately 40 % of 2,6-DMP within 5 days. The GC-Mass analysis for the degradation products indicated that mono- and dihydroxylation for the pyridine ring and oxidation of one or both of the terminal methyl groups have occurred. Based on this finding, this isolated bacterial can further be utilized for bioremediation purposes.

Lithostratigraphic definition of the Anisian carbonate-ramp deposit of the Annaberg Formation (Middle Triassic, Northern Calcareous Alps, Austria)

Concerning the Middle Triassic stratigraphic succession of the Northern Calcareous Alps (NCA), a modern, litho- and biostratigraphic oriented evaluation of the early- and middle Anisian Annaberg Formation is presented. Due to the fact, that Middle Triassic formations are characterized by a wide distribution within the NCA, any lithostratigraphic definitions of these formations would be of great benefit for mapping geologists, engineers and hydrogeologists. The lithostratigraphic term Annaberg Formation may substitute former designations like “Alpiner Muschelkalk”, “Anisian Limestone and Dolomite” or, partly, “Gutenstein Limestone”. It is exclusively of Anisian age and earlier then the Steinalm and Reifling Formation. Mainly based on microfacies data and lithological data, we define the Annaberg Formation (former: Annaberg Limestone) as one of the most significant Middle Triassic lithostratigraphic units within the NCA. After a detailed description of the type area, findings gained in other areas of the NCA are incorporated to obtain the largest possible overview about the lithological variability and constituents of the Annaberg Formation. As a result, we can describe the Annaberg Formation as mainly organic-rich, medium bedded wackestone, containing remnants of crinoids, little bivalves and gastropods. Typically, fossil-rich layers with accumulations of bivalves and crinoids can often be observed within the Annaberg Formation. In contrast to the Gutenstein Formation no siliceous concretions or fossils (like radiolarians) appear and the fauna is in the main shallow marine. The rock-colour varies from dark- to medium-grey and the bench thicknesses are greater than within the Gutenstein Formation sensu stricto. The fossil content is also larger than in the essentially anaerobe Gutenstein Formation. With respect to the Virgloria Formation the Annaberg Formation is rather planar bedded, not so rich in bioturbation-structures and poor in silica and clay. Hence, the depositional environment of the Annaberg Formation can be described as a restricted carbonate ramp succession, with only minor water movement and separated from the open sea by a shoal with crinoid and brachiopod meadows. Breccias may be an indication for collapse-structures and slumping. In addition, knife-cavity structures (“Messerstichkalke”) indicate an occasional hypersaline environment with precipitation of evaporite-minerals like gypsum. Fossil-rich layers with accumulations of molluscs and crinoids may indicate short-term storm affected sedimentation.

Exploring Microbial Resource of Different Rhizocompartments of Dominant Plants Along the Salinity Gradient Around the Hypersaline Lake Ejinur

Lake littoral zones can also be regarded as another extremely hypersaline environment due to hypersaline properties of salt lakes. In this study, high-throughput sequencing technique was used to analyze bacteria and fungi from different rhizocompartments (rhizosphere and endosphere) of four dominant plants along the salinity gradient in the littoral zones of Ejinur Salt Lake. The study found that microbial α-diversity did not increase with the decrease of salinity, indicating that salinity was not the main factor on the effect of microbial diversity. Distance-based redundancy analysis and regression analysis were used to further reveal the relationship between microorganisms from different rhizocompartments and plant species and soil physicochemical properties. Bacteria and fungi in the rhizosphere and endosphere were the most significantly affected by SO42–, SOC, HCO3–, and SOC, respectively. Correlation network analysis revealed the potential role of microorganisms in different root compartments on the regulation of salt stress through synergistic and antagonistic interactions. LEfSe analysis further indicated that dominant microbial taxa in different rhizocompartments had a positive response to plants, such as Marinobacter, Palleronia, Arthrobacter, and Penicillium. This study was of great significance and practical value for understanding salt environments around salt lakes to excavate the potential microbial resources.