Antiviral susceptibility of clade 2.3.4.4b highly pathogenic avian influenza A(H5N1) viruses isolated from birds and mammals in the United States, 2022

Clade 2.3.4.4b highly pathogenic avian influenza (HPAI) A(H5N1) viruses that are responsible for devastating outbreaks in birds and mammals pose a potential threat to public health. Here, we evaluated their susceptibility to influenza antivirals. Of 1,015 sequences of HPAI A(H5N1) viruses collected in the United States during 2022, eight viruses (∼0.8%) had a molecular marker of drug resistance to an FDA-approved antiviral: three adamantane-resistant (M2-V27A), four oseltamivir-resistant (NA-H275Y), and one baloxavir-resistant (PA-I38T). Additionally, 31 viruses contained mutations that may reduce susceptibility to inhibitors of neuraminidase (NA) (n = 20) or cap-dependent endonuclease (CEN) (n = 11). A panel of 22 representative viruses was tested phenotypically. Overall, clade 2.3.4.4b A(H5N1) viruses lacking recognized resistance mutations were susceptible to FDA-approved antivirals. Oseltamivir was least potent at inhibiting NA activity, while the investigational NA inhibitor AV5080 was most potent, including against NA mutants. A novel NA substitution T438N conferred 12-fold reduced inhibition by zanamivir, and in combination with the known marker N295S, synergistically affected susceptibility to all five NA inhibitors. In cell culture-based assays HINT and IRINA, the PA-I38T virus displayed 75- to 108-fold and 37- to 78-fold reduced susceptibility to CEN inhibitors, baloxavir and the investigational AV5116, respectively. Viruses with PA-I38M or PA-A37T showed 5- to 10-fold reduced susceptibilities. As HPAI A(H5N1) viruses continue to circulate and evolve, close monitoring of drug susceptibility is needed for risk assessment and to inform decisions regarding antiviral stockpiling

Effective complex hydrophobizators for self-cleaning facade materials

In the work presented here, we present the research results of the effect of self-cleaning of surfaces. The methods of its achievement such as photocatalytic and the method of hydrophobization are considered. The known methods for determining the contact angle of wetting are used. An installation for generating a low-temperature nonequilibrium plasma was used to modify a fine aggregate. The contact angles of wetting obtained as a result of the use of various formulations of hydrophobizing suspensions are determined experimentally. A modification of the quartz filling matter was also carried out. Experiments have confirmed the technical effectiveness of hydrophobisers and the enhancement of their properties when dispersed fillers are used. Even higher values of wetting contact angle were achieved using a plasma-modified filling matter

Soil CO2 emission, microbial biomass, and microbial respiration of woody and grassy areas in Moscow (Russia)

Purpose: Urbanization significantly changes the carbon balance of the terrestrial ecosystem, an important component of which is soil CO2 emission. One of the main sources of soil CO2 emission is microbial decomposition of soil organic matter. In this regard, we hypothesized a relationship between soil CO2 emission and soil microbial properties (biomass, respiratory activity) in Moscow megapolis areas. Materials and methods: Soil CO2 emission was measured monthly (May–October) from the surface (or soil respiration, RS) and after the sequential removal of the two top 10-cm soil layers at woody (forest park, public garden) and grassy (grassland, arable) areas. Soil temperature (ST) and soil water content were recorded in 0–10-, 10–20-, and 20–30-cm layers, from which samples were taken to measure microbial biomass carbon (Cmic) and basal (microbial) respiration (BR). Results and discussion: RS ranged from 0.3 to 14.7 μmol СО2 m−2 s−1, with average values of 1.0, 5.4, 7.5, and 8.8 μmol СО2 m−2 s−1 for arable, forest park, public garden, and grassland, respectively. Removing the topsoil layer in woody areas resulted in higher CO2 release to the atmosphere than in grassy ones. Topsoil Cmic was on average 110, 331, 517, and 549 μg C g−1 and BR was 0.42, 0.87, 0.47, and 0.92 μg C-СО2 g−1 h−1 for arable, forest park, public garden, and grassland, respectively. Subsoil Cmic and BR were 1.5–3 times and 30–62% lower than in topsoil. RS in woody areas was more strongly dependent on ST than in grassy areas. Strong positive correlation between RS and topsoil Сmic and Corg (R2 = 0.98–0.99) was found. Conclusions: The RS of different Moscow’s areas might be predicted on the base of soil Cmic or Corg experimental data

Temperature Sensitivity of Topsoil Organic Matter Decomposition Does Not Depend on Vegetation Types in Mountains

Rising air temperatures caused by global warming affects microbial decomposition rate of soil organic matter (SOM). The temperature sensitivity of SOM decomposition (Q(10)) may depend on SOM quality determined by vegetation type. In this study, we selected a long transect (3.6 km) across the five ecosystems and short transects (0.1 km) from grazed and ungrazed meadows to forests in the Northwest Caucasus to consider different patterns in Q(10) changes at shift of the vegetation belts. It is hypothesized that Q(10) will increase along altitudinal gradient in line with recalcitrance of SOM according to kinetics-based theory. The indicators of SOM quality (BR:C, respiration per unit of soil C; MBC:C, ratio of microbial biomass carbon to soil carbon; soil C:N ratio) were used for checking the hypothesis. It was shown that Q(10) did not differ across vegetation types within long and short transects, regardless differences in projective cover (14-99%) and vegetation species richness (6-12 units per plot). However, Q(10) value differed between the long and short transects by almost two times (on average 2.4 vs. 1.4). Such a difference was explained by environmental characteristics linked with terrain position (slope steepness, microclimate, and land forms). The Q(10) changes across studied slopes were driven by BR:C for meadows (R-2 = 0.64; negative relationship) and pH value for forests (R-2 = 0.80; positive relationship). Thus, proxy of SOM quality explained Q(10) variability only across mountain meadows, whereas for forests, soil acidity was the main driver of microbial activity

Microbial C-availability and organic matter decomposition in urban soils of megapolis depend on functional zoning

Urbanization has various strong effects on soil processes. Despite an increasing number of studies focused on soil carbon (C) distribution and stocks within cities, the C and nutrient availability to microorganisms and their capacity to decompose organic matter remain nearly unknown. The factors responsible for these processes in megacities are characterized by a very high spatial heterogeneity and therefore, their effects should be investigated as related to specific environmental conditions – common for urban functional zones. This study focuses on the examination of the texture, C, available phosphorus (AP) and potassium (AK), mineral nitrogen, pH, and heavy metals (HMs) contents considering microbial C-availability (ratio of microbial biomass to C) and organic matter decomposition (BR) in soils of Moscow megapolis. The sampling sites were referred to recreational, residential and industrial zones. In the industrial and residential zones, the pH, AK, AP, and HMs were increased compared to recreational. Concurrently, the microbial С-availability and BR were much less in these zones. The high pH and AP content had negative effects on the BR for all soils. Soil segregation into groups (C-poor and C-rich, light texture and heavy texture) reduced heterogeneity and showed the additional patterns. In C-poor soils, the AP effect on BR was confirmed, but not of pH. The AK and Cu contents had negative effects on C-availability for C-poor and light soils, respectively. We conclude that careful control of the soil phosphorus and potassium contents as well as texture is necessary for planning the soil construction in megacities to consider their optimal functioning

Microbial Properties of Urban Soils With Different Land-Use History in New Moscow

Soil microbial properties are highly sensitive to present and past anthropogenic influences such as urban expansion, which is among the most drastic form of land-use change having substantial consequences for soils. New Moscow is an ambitious project to reduce the population of Moscow city that resulted in a rapid urbanization of former croplands, fallow lands, and forested areas. This study aimed to investigate the effects of historical land use in New Moscow on urban soil microbial properties. The land-use map of New Moscow from 2016 was compared with a similar map from 1981 to investigate the main urbanization pathways and land-use history of the new urbanized areas. Compared with 1981, the 2016 urban areas were more than three times greater, and the forest, pasture, and cropland areas were reduced by 9%, 87%, and 18%, respectively. Topsoil (0–10 cm) and subsoil (10–30 cm) samples were collected from 11 nonurbanized and 11 urbanized areas from current and former forest, pasture, and cropland soils. Soil microbial biomass carbon and respiration rates and chemical (pH and total C and N) and physical (bulk density and texture) properties were compared. Urban soils converted from forests and pastures showed negative effects of urbanization on topsoil microbial properties, whereas a conversion of cropland to urban soil increased microbial biomass carbon and microbial respiration. Soil microbial properties and N and C contents showed a strong correlation. The influence of historic land use on subsoil microbial properties was not significant

Consequences of Grazing Cessation for Soil Environment and Vegetation in a Subalpine Grassland Ecosystem

Areas covered by seminatural grasslands have been in constant decline for decades in Europe. This trend is particularly strong for mountain territories, where such traditional agricultural practices as cattle grazing are no longer economically feasible. This study was conducted in the subalpine pasture of Cinte Tesino (TN, Italy), where local farmers have applied the following different management strategies: shorter and longer grazing durations during the season and a complete abandonment for the last 15 years. We aimed to study how these different management strategies impact the functioning and diversity of vegetation and the chemical and biological characteristics of the soil. Species richness was higher in plots subjected to longer grazing with a prevalence of D. caespitosa in terms of biomass share. A decline in species richness in abandoned plots was accompanied by an increase in the share of other graminoids in collected biomass. A concomitant increase in leaf N concentration and light availability in grazed plots resulted in higher photosynthetic efficiency in some species, as revealed by the δ13C of plant tissues. Soils under grazing were characterised by a higher concentration of total and extractable N, almost doubled microbial biomass C and increased extracellular enzymes activity, evidencing nutrient cycling mobilization. While the microbial pool was characterised by lower mineralization rates, C was lost from the soil with 15 years of abandonment. The longer grazing season demonstrated to be the most beneficial, promoting species richness, C accumulation and better soil microbial functioning. A change in soil pH from strongly acidic to moderately acidic with longer grazing is likely one of the important factors adding to the success in the functioning of primary producers and decomposers in this site

Carbon dioxide emission and soil microbial respiration activity of Chernozems under anthropogenic transformation of terrestrial ecosystems

The total soil CO2 emission (EM) and portion of microbial respiration were measured (in situ; May, June, July 2015) in Chernozems typical of virgin steppe, oak forest, bare fallow and urban ecosystems (Kursk region, Russia). In soil samples (upper 10 cm layer), the soil microbial biomass carbon (Cmic), basal respiration (BR) and fungi-to-bacteria ratio were determined and the specific microbial respiration (BR / Cmic = qCO2) was calculated. The EM was varied from 2.0 (fallow) to 23.2 (steppe) g СО2 m-2 d-1. The portion of microbial respiration in EM was reached in average 83, 51 and 60% for forest, steppe and urban, respectively. The soil Cmic and BR were decreased along a gradient of ecosystems transformation (by 4 and 2 times less, respectively), while the qCO2 of urban soil was higher (in average by 42%) compared to steppe, forest and fallow. In urban soil the Cmic portion in soil Сorg and Сfungi-to-Сorg ratio were by 2.6 and 2.4 times less than those for steppe. The relationship between microbial respiration and BR values in Chernozems of various ecosystems was significant (R2 = 0.57)

Technosols on mining wastes in the subarctic: Efficiency of remediation under Cu-Ni atmospheric pollution

The copper-nickel factory's emissions in the Murmansk region, Russia, led to the degradation of plant cover and topsoil with the subsequent formation of industrial barrens. In this study, the industrial barrens were remediated by means of Technosol engineering, when grasses were sown on the two different types of mining wastes (carbonatite and serpentinite-magnesite) covered by hydroponic vermiculite. The serpentinite-magnesite waste was significantly different from the carbonatite waste in the content of silicon (Si) and manganese (Mn), pH, and texture. Both wastes had an alkaline pH level and high content of calcium (Ca) and magnesium (Mg). The vegetation and Technosol properties at the remediated sites were analyzed in 2017 and compared to the initial state (2010 year) to assess the efficiency of the long-term remediation. The quality and sustainability of Technosols based on the serpentinite-magnesite wastes were substantially higher compared to the carbonatite-based Technosol. Biomass and a projective cover of the grass community depended on Si content in the original mining waste and were found to be higher in the serpentinite-magnesite Technosol. The content of organic carbon and its fractions, microbial biomass and basal respiration after seven years of Technosol evolution was comparable to natural values. These parameters were directly related to plant cover state and were inversely proportional to copper (Cu) content in Technosol. The Technosol development led to the reduction of nickel (Ni) and Cu migration in soil-plant ecosystems due to neutralization and adsorption properties of mining wastes and phytostabilization by underground parts of grass communities. The Technosol development in its early stage of pedogenesis indicates the efficiency of applied remediation technology to the degraded acidic soil under the conditions of industrial atmospheric pollution

Organic matter accumulation by alkaline-constructed soils in heavily metal-polluted area of Subarctic zone

Purpose: The research aimed to investigate properties and functions of soils constructed from alkaline mining wastes of different origin to remediate the industrial barren resulted from long-term emissions of the copper-nickel factory in the Subarctic region (Kola Peninsula, Russia). Conventional indicators of the remediation effectiveness (pH and metal content in geochemical fractions) were related to the indicators of soil functions such as biomass production, accumulation of organic carbon, microbial activity, and soil respiration. Materials and methods: The experimental area included two sites with polluted and degraded Podzol and Histosol soils located in 1.5 and 0.7 km from the nonferrous (Cu-Ni) smelter, respectively. At the sites, artificial soil constructions were made from mining wastes or quarry sand covered by the vermiculite layer with lawn grasses planted on top. Plant biomass was collected every year starting from the experiment set-up. In 5 to 8 years, soil samples were collected on the layer basis, and chemical, biological, and morphological properties were analyzed. Sequential fractionation of metals was conducted using a modified Tessier’s scheme. The microbial biomass and its respiration activity were determined. Micromorphological studies were conducted using an optical microscope. Soil respiration was measured on-site by IRGA with simultaneous observations of soil moisture and temperature. Results: The plant growth and residues' deposition at both experimental sites triggered carbon accumulation and resulted in 2–3 times higher content of organic carbon in the upper constructed soil layer compared to the initial content in mining wastes. Carbon accumulation was a key driver for the development of soil microbial communities and had a positive effect on the metal immobilization. This effect was strengthened by high pH inherited from the alkaline wastes and resulted in the performance of constructed soils as geochemical barriers. In their upper layers, where the root biomass was the highest, about 30–60% of Cu and Ni were bound by organic matter. In the underlying polluted soil, the most toxic water-soluble metal fraction was completely neutralized; and the metal concentrations in exchangeable fraction decreased by a factor of four improving the habitat conditions of the microbiome. Organic matter accumulation by clay material with the formation of organo-mineral films was found in the vermiculite-lizardite variant. Conclusion: Soil constructions made from alkaline mining wastes in the Subarctic supported the development of plant and microbial communities, organic matter accumulation, and metal immobilization. This technology allows protecting the environment from further pollution under the continuous emissions of the copper-nickel factory