A possible unique ecosystem in the endoglacial hypersaline brines in Antarctica.

Here, we present the results related to a new unique terrestrial ecosystem found in an englacial hypersaline brine found in Northern Victoria Land (Antarctica). Both the geochemistry and microbial (prokaryotic and fungal) diversity revealed an unicity with respect to all the other known Antarctic brines and suggested a probable ancient origin mainly due a progressive cryoconcentration of seawater. The prokaryotic community presented some peculiarities, such as the occurrence of sequences of Patescibacteria (which can thrive in nutrient-limited water environments) or few Spirochaeta, and the presence of archaeal sequences of Methanomicrobia closely related to Methanoculleus, a methanogen commonly detected in marine and estuarine environments. The high percentage (35%) of unassigned fungal taxa suggested the presence of a high degree of undiscovered diversity within a structured fungal community (including both yeast and filamentous life forms) and reinforce the hypothesis of a high degree of biological uniqueness of the habitat under study.

The effect of substituting energy crop with agricultural waste on the dynamics of bacterial communities in a two-stage anaerobic digester.

The replacement of energy crops with agricultural waste in biogas production through anaerobic digestion (AD) is both an environmentally sustainable and economically profitable strategy. However, the change of feeding mix in AD might result in nutrient imbalance or increase of the ammonium concentration, negatively affecting the activity of the microbes responsible for the process. In the present study the structure and dynamics of the bacterial communities of a full-scale two-stage AD plant, composed of a hydrolysis/acidogenesis (H) and an acetogenesis/methanogenesis (M) tanks, was monitored during feedstock substitution. Energy crop (triticale) was replaced by poultry manure litter and olive mill pomace. The increase percentage of poultry manure litter (up to 8.6%) and olive mill pomace (up to 30.5%) in the recipe incremented the total solids (up to 21% in H) and, consequently, the nitrogen content in the digestate (6.7 g N/kg in the solid fraction in H and 4-5 g NH4+-N/L in the liquid fraction). This favored the growth of Lactococcus sp. with consequent increment of lactate production (∼ 1 mg L-1 last two days of the survey) and the establishment of Weissella and Lactobacillus spp. Syntrophic acetate-oxidizers, including Syntrophaceticus (6% ± 1.7%), were detected manly in M but were negatively affected by the addition of the poultry manure litter, while the sulfate-reducing bacteria correlated with the variations of the volatile fatty acids. Planctomycetes putatively capable of anammox process were also found in the H during the first two days of the survey and accounted for 0.3 ± 0.01% of the total bacterial community. The stability of the process during feedstock change is the result of the shift of bacterial populations of different functional groups that showed peculiar adaptation patterns in the two stages of the plant.

Copper and zinc as a window to past agricultural land-use.

Intensive agricultural management significantly affects soil chemical properties. Such impacts, depending on the intensity of agronomic practices, might persist for several decades. We tested how current soil properties, especially heavy metal concentrations, reflect the land-use history over a 24,000 ha area dominated by intensive apple orchards and viticulture (South Tyrol, ITA). We combined georeferenced soil analyses with land-use maps from 1850 to 2010 in a space-for-time approach to detect the accumulation rates of copper and zinc and understand how present-day soil heavy metal concentrations reflect land-use history. Soils under vineyards since the 1850s showed the highest available copper concentration (median of 314.0 mg kg-1, accumulation rate between 19.4 and 41.3 mg kg-1·10 y-1). Zinc reached the highest concentration in the same land-use type (median of 32.5 mg kg-1, accumulation rate between 1.8 and 4.4 mg kg-1·10 y-1). Using a random forest approach on 44,132 soil samples, we extrapolated land-use history on the permanent crop area of the region, reaching an accuracy of 0.72. This suggests that combining current soil analysis, historical management information, and machine learning models provides a valuable tool to predict land-use history and understand management legacies.

Nonlinear analysis of tRNAs nucleotide sequences by random walks: randomness and order in the primitive informational polymers.

In order to test the hypothesis that the nucleotide sequences of the primitive informational polymers might not be chosen randomly and in the attempt to compare among taxa, we propose a comparison of computer-generated random sequences with tRNAs nucleotide sequences present in the bacterial and archaeal genomes, being tRNAs molecules possible "fossils" of the time (billions years ago) in which life arose. Our approach is based on the analysis of sequences of tRNAs described as random walks and the distances from the origin evaluated by the use of nonlinear indexes (largest Lyapunov exponent, entropy, BDS statistic). Six different tRNAs of Bacteria and Archaea (ten Archaea and ten Bacteria, thermophilic and mesophilic ones; n = 120), and computer-generated random sequences (n = 50) were studied. Our data show that tRNAs present indices statistical lower than the ones of computer-generated random data (tRNAs own a more ordered sequence than random ones: Lyapunov, p < 0.01; entropy, p < 0.05; BDS, p < 0.01). The observed deviation from pure randomness should be arisen from some constraints like the secondary structure of this biologic macromolecule and/or from a "frozen" stochastic transition, or even from the possible peculiar origin of tRNA by replication of older proto-RNA. Comparing between taxa, in the species studied, Bacteria present BDS and Base ratio (G+C)/(A+T) indexes statistically lower than in Archaea, together which a 20% of entropy increase. The analysis of a greater number of tRNAs and species will permit to explain if this finding, showing a higher randomness in the bacterial tRNAs sequences, is linked to the different base ratio, to the different environments in which the microorganisms live or to an evolutionary effect.

Kodamaea ohmeri isolate from two immunocompromised patients: first report in Italy.

Kodamaea ohmeri is an unusual yeast-form fungus that has recently been identified as an important aetiological agent of fungaemia, endocarditis, cellulitis, funguria and peritonitis in immunocompromised patients. We present two new isolated of K. ohmeri. The microorganisms were identified by CHROMagar Candida medium, VitekII system and API ID32C. Biochemical identification of the two yeast isolates was confirmed by sequence analysis of the 26S ribosomal DNA. Antifungal susceptibility testing done by Sensititre YeastOne showed that the isolates were susceptible to amphotericin B, voriconazole and itraconazole. This work is the first report of isolation of K. ohmeri in immunocompromised patients in Italy.

[Short-term and long-term surgical prophylaxis with pefloxacin]. / Short-term e long-term profilassi chirurgica con pefloxacina.

In the present study the efficacy and safety of pefloxacin (400 mg/5 ml vial) intravenously administrated for surgical prophylaxis was assessed. Nine hundred and fifty-two patients were treated (599 M, 343 F), with a mean age of 57.9 years +/- 18.6 SD, and in all cases surgical prophylaxis was carried out according to the following scheme: short-term with 2 vials (800 mg) 1 h before the operation, repeated at 12 and 24 hours after the operation; long-term 2 vials (800 mg) 1 h before the operation repeated at 12 and 24 hours after the operation and followed by 1 vial every 12 h for other 2 days. The choice between the two schemes was conditioned by the type of operation and by the basic conditions of the patient. Pefloxacin was seen to be effective in preventing the onset of post-surgical infections (97%), also maintaining the clinical parameters considered within normal limits. Safety was also highly satisfactory, since only 22 (2.3%) cases of side effects occurred, particularly involving the gastro-intestinal system. Thus, in conclusion, the validity of pefloxacin in surgical prophylaxis, with special emphasis on its efficacy in elderly and compromised patients is asserted.