<Emphasis Type="Italic">Micrococcus luteus</Emphasis> - Survival in Amber

A growing body of evidence now supports the isolation of microorganisms from ancient materials. However, questions about the stringency of extraction methods and the genetic relatedness of isolated organisms to their closest living relatives continue to challenge the authenticity of these ancient life forms. Previous studies have successfully isolated a number of spore-forming bacteria from organic and inorganic deposits of considerable age whose survival is explained by their ability to enter suspended animation for extended periods of time. However, despite a number of putative reports, the isolation of non-spore-forming bacteria and an explanation for their survival have remained enigmatic. Here we describe the isolation of non-spore-forming cocci from a 120-million-year-old block of amber, which by genetic, morphological, and biochemical analyses are identified as belonging to the bacterial species Micrococcus luteus. Although comparison of 16S rRNA sequences from the ancient isolates with their modern counterparts is unable to confirm the precise age of these bacteria, we demonstrate, using complementary molecular and cell biological techniques, evidence supporting the view that these (and related modern members of the genus) have numerous adaptations for survival in extreme, nutrient-poor environments, traits that will assist in this bacterias persistence and dispersal in the environment. The bacterias ability to utilize succinic acid and process terpine-related compounds, both major components of natural amber, support its survival in this oligotrophic environment.     

Population decline in California spotted owls near their southern range boundary

Species worldwide have begun to shift their range boundaries in response to climate change and other anthropogenic causes, with population declines at the trailing edge of a species' range often foreshadowing future changes in core parts of the range. Therefore, we analyzed a 30-year (1991–2019) data set for the California spotted owl (Strix occidentalis occidentalis) near its southern range boundary in southern California, USA, that included the largest regional population (San Bernardino Mountains) to estimate trends in territory occupancy and reproduction. We then assessed how these demographic rates were affected by habitat, wildfire, fuel treatments, and climate. Mean occupancy declined from 0.82 to 0.39 during our study, whereas reproductive output showed no temporal trends ( young/occupied territory). Territory extinction (extirpation) rates were relatively low in territories with more large trees (≥50 cm dbh), and colonization increased strongly with large tree density for low-elevation territories within the shrub-woodland ecotype but not for higher-elevation territories within mixed-conifer forest. High-severity wildfire had an adverse effect on occupancy: territory extinction rates steadily increased with the amount of high-severity fire within an owl territory during the previous 10 years, while colonization declined to nearly zero when ≥40% of a territory burned at high-severity during the previous 10 years. The effects of high-severity fire were unlikely to be confounded with post-fire fuel treatments, which primarily consisted of the removal, burning, or scattering of brush and small trees and snags (<40.6 cm dbh) and affected much smaller areas than high-severity fire. Of the 40 territories that received fuel treatments within 10 years of a fire, only 3 of them had post-fire fuel treatments that affected >5% of the territory, whereas average area burned at high severity for all 40 territories was 17%. Fuel treatments intended to modify fire behavior and reduce the likelihood of large, high-severity fires led to increases in territory extinction and colonization such that their net effect on occupancy was minimal. Our simulations of occupancy dynamics indicated that high-severity fire accounted for 9.6% of the observed decline in occupancy, whereas fuel treatments effectively accounted for none of the decline. Spotted owl reproductive output was lower at territories where fuel treatments occurred, but low- to moderate-severity fire resulted in much larger, population-level reductions in reproductive output (141 fewer young) from 2006–2019 than treatments (19 fewer young). Thus, the benefits of fuel treatments that reduce fire occurrence and severity appear to outweigh potential short-term costs to spotted owls and their habitat. Because high-severity fire only explained a modest amount of the long-term occupancy decline and much of the decline occurred in the 1990s before large fires occurred, additional factors are likely adversely affecting the owl population and merit further study. Nevertheless, the large observed population decline, limited evidence of owl dispersal among mountain ranges in the southern California metapopulation, and negative effects of increasingly large and severe fire suggest that California spotted owls at their southern range boundary are vulnerable to extirpation. In an era of climate change, owls in the core part of the range will likely become increasingly susceptible to warmer temperatures and increased severe fire activity in the future. Thus, the restoration of historical, low-severity fire regimes through fuels management while maintaining large trees is important to improving owl persistence.     

The abiotic stress as a factor responsible for gypsy moth outbreaks

The close quantitative interrelation between the reaction of birch to abiotic stress (spring–summer droughts) (the degree to which the yearly radial increment of trees decreases) and entomoresistance has been established. Tree stands that were heavily defoliated by gypsy moth showed a much stronger reaction to the droughts which preceded the outbreaks by the decrease in their radial increment than those weakly defoliated by this phytophagous insect. The reaction of trees to the abiotic stress is regarded as the key factor that controls the drop in their entomoresistance during outbreaks of gypsy moth in woods damaged by anthropogenic effects.     

Investigation of pulsed X-ray radiation of a plasma focus in a broad energy range

The results of the experimental investigations of the spectral composition of plasma focus X-ray radiation in the photon energy range of 1.5 keV-400 keV are presented. Three regions in the radiation spectrum where the latter is of a quasi-thermal nature with a corresponding effective temperature are distinguished.     

Detection of Salt Marsh Vegetation Stress and Recovery after the Deepwater Horizon Oil Spill in Barataria Bay,Gulf of Mexico Using AVIRIS Data

The British Petroleum Deepwater Horizon Oil Spill in the Gulf of Mexico was the biggest oil spill in US history. To assess the impact of the oil spill on the saltmarsh plant community, we examined Advanced Visible Infrared Imaging Spectrometer (AVIRIS) data flown over Barataria Bay, Louisiana in September 2010 and August 2011. Oil contamination was mapped using oil absorption features in pixel spectra and used to examine impact of oil along the oiled shorelines. Results showed that vegetation stress was restricted to the tidal zone extending 14 m inland from the shoreline in September 2010. Four indexes of plant stress and three indexes of canopy water content all consistently showed that stress was highest in pixels next to the shoreline and decreased with increasing distance from the shoreline. Index values along the oiled shoreline were significantly lower than those along the oil-free shoreline. Regression of index values with respect to distance from oil showed that in 2011, index values were no longer correlated with proximity to oil suggesting that the marsh was on its way to recovery. Change detection between the two dates showed that areas denuded of vegetation after the oil impact experienced varying degrees of re-vegetation in the following year. This recovery was poorest in the first three pixels adjacent to the shoreline. This study illustrates the usefulness of high spatial resolution airborne imaging spectroscopy to map actual locations where oil from the spill reached the shore and then to assess its impacts on the plant community. We demonstrate that post-oiling trends in terms of plant health and mortality could be detected and monitored, including recovery of these saltmarsh meadows one year after the oil spill.     

Simulation of individual risk based on the results of exercise tests and analysis of risk factors

The materials of a cross-sectional and prospective Russian-US population study (the Russian Lipid Research Clinics Prevalence Study) have been used to develop models intended for estimating the probability of death from coronary heart disease, all cardiovascular disease, and all causes over 10 and 20 years. The prediction was performed by constructing artificial neural networks. Testing on an independent sample has shown an accuracy of 66–73%.