Bacterial Necromass Is Rapidly Metabolized by Heterotrophic Bacteria and Supports Multiple Trophic Levels of the Groundwater Microbiome.

Pristine groundwater is a highly stable environment with microbes adapted to dark, oligotrophic conditions. Input events like heavy rainfalls can introduce the excess particulate organic matter, including surface-derived microorganisms, thereby disturbing the groundwater microbiome. Some surface-derived bacteria will not survive this translocation, leading to an input of necromass to the groundwater.

Combined effect of salicylic acid and potassium mitigates drought stress through the modulation of physio-biochemical attributes and key antioxidants in wheat.

Improving physio-biochemical traits in wheat under drought stress conditions has received more research attention in recent years for better adaptability and higher yield. In this study, we explored the potential bio-physiological mechanisms underlying improved plant growth and water use efficiency in wheat following soil application of potassium (0 and 100 kg ha) and seed primed salicylic acid (SA) (150 mg per L) and SA foliar application (100 mg per L) under drought stresses (100%, 60% and 30% FC). Two years' average data revealed that inducing drought stress resulted in a decrease in plant pigments content, growth traits, and plant water status however, the influence was substantially reduced with the combined application of K and SA under drought stress conditions.

Heterologous Lactate Synthesis in sp. Strain PCC 6803 Causes a Growth Condition-Dependent Carbon Sink Effect.

Cyanobacteria are considered promising hosts for product synthesis directly from CO via photosynthetic carbon assimilation. The introduction of heterologous carbon sinks in terms of product synthesis has been reported to induce the so-called "carbon sink effect," described as the release of unused photosynthetic capacity by the introduction of additional carbon. This effect is thought to arise from a limitation of carbon metabolism that represents a bottleneck in carbon and electron flow, thus enforcing a downregulation of photosynthetic efficiency.

PredicTF: prediction of bacterial transcription factors in complex microbial communities using deep learning.

Background: Transcription factors (TFs) are proteins controlling the flow of genetic information by regulating cellular gene expression. A better understanding of TFs in a bacterial community context may open novel revenues for exploring gene regulation in ecosystems where bacteria play a key role. Here we describe PredicTF, a platform supporting the prediction and classification of novel bacterial TF in single species and complex microbial communities.

In silico deconjugation of glucuronide conjugates enhances tandem mass spectra library annotation of human samples.

Mass spectral library annotation of liquid chromatography-high resolution tandem mass spectrometry (LC-HRMS/MS) data is a reliable approach for fast identification of organic contaminants and toxicants in complex environmental and biological matrices. While determining the exposure of humans or mammals, it is indispensable to include phase I and phase II metabolites (conjugates) along with the parent compounds, but often, tandem mass spectra for these are unavailable. In this study, we present and evaluate a strategy for annotating glucuronide conjugates in LC-HRMS/MS scans by applying a neutral loss search for detection, then truncating the spectra which we refer to as in silico deconjugation, and finally searching these against mass spectral libraries of the aglycones.

Trait-based responses to cessation of nutrient enrichment in a tundra plant community.

Plant communities worldwide show varied responses to nutrient enrichment-including shifts in species identity, decreased diversity, and changes in functional trait composition-but the factors determining community recovery after the cessation of nutrient addition remain uncertain. We manipulated nutrient levels in a tundra community for 6 years of nutrient addition followed by 8 years of recovery. We examined how community recovery was mediated by traits related to plant resource-use strategy and plant ability to modify their environment.

Temporal rarity is a better predictor of local extinction risk than spatial rarity.

Spatial rarity is often used to predict extinction risk, but rarity can also occur temporally. Perhaps more relevant in the context of global change is whether a species is core to a community (persistent) or transient (intermittently present), with transient species often susceptible to human activities that reduce niche space. Using 5-12 yr of data on 1,447 plant species from 49 grasslands on five continents, we show that local abundance and species persistence under ambient conditions are both effective predictors of local extinction risk following experimental exclusion of grazers or addition of nutrients; persistence was a more powerful predictor than local abundance.

Microbial Identification, High-Resolution Microscopy and Spectrometry of the Rhizosphere in Its Native Spatial Context.

During the past decades, several stand-alone and combinatorial methods have been developed to investigate the chemistry (i.e., mapping of elemental, isotopic, and molecular composition) and the role of microbes in soil and rhizosphere.

Species loss due to nutrient addition increases with spatial scale in global grasslands.

The effects of altered nutrient supplies and herbivore density on species diversity vary with spatial scale, because coexistence mechanisms are scale dependent. This scale dependence may alter the shape of the species-area relationship (SAR), which can be described by changes in species richness (S) as a power function of the sample area (A): S = cA , where c and z are constants. We analysed the effects of experimental manipulations of nutrient supply and herbivore density on species richness across a range of scales (0.

Thermal flexibility and a generalist life history promote urban affinity in butterflies.

Urban expansion poses a serious threat to biodiversity. Given that the expected area of urban land cover is predicted to increase by 2-3 million km by 2050, urban environments are one of the most widespread human-dominated land-uses affecting biodiversity. Responses to urbanization differ greatly among species.

Demographic analysis of an Israeli Carpobrotus population.

Carpobrotus species are harmful invaders to coastal areas throughout the world, particularly in Mediterranean habitats. Demographic models are ideally suited to identify and understand population processes and stages in the life cycle of the species that could be most effectively targeted with management. However, parameterizing these models has been limited by the difficulty in accessing the cliff-side locations where its populations are typically found, as well as accurately measuring the growth and spread of individuals, which form large, dense mats.

Suppression of an Invasive Native Plant Species by Designed Grassland Communities.

Grassland biodiversity is declining due to climatic change, land-use intensification, and establishment of invasive plant species. Excluding or suppressing invasive species is a challenge for grassland management. An example is , an invasive native plant in wet grasslands of Central Europe, that is causing problems to farmers by being poisonous, overabundant, and fast spreading.

Community change can buffer chronic nitrogen impacts, but multiple nutrients tip the scale.

Anthropogenic nitrogen (N) inputs are causing large changes in ecosystems worldwide. Many previous studies have examined the impact of N on terrestrial ecosystems; however, most have added N at rates that are much higher than predicted future deposition rates. Here, we present the results from a gradient of experimental N addition (0-10 g·N·m ) in a temperate grassland.

Roux-en-Y gastric bypass contributes to weight loss-independent improvement in hypothalamic inflammation and leptin sensitivity through gut-microglia-neuron-crosstalk.

Objective: Hypothalamic inflammation and endoplasmic reticulum (ER) stress are extensively linked to leptin resistance and overnutrition-related diseases. Surgical intervention remains the most efficient long-term weight-loss strategy for morbid obesity, but mechanisms underlying sustained feeding suppression remain largely elusive. This study investigated whether Roux-en-Y gastric bypass (RYGB) interacts with obesity-associated hypothalamic inflammation to restore central leptin signaling as a mechanistic account for post-operative appetite suppression.

Phylogenetic and metabolic diversity have contrasting effects on the ecological functioning of bacterial communities.

Quantifying the relative contributions of microbial species to ecosystem functioning is challenging, because of the distinct mechanisms associated with microbial phylogenetic and metabolic diversity. We constructed bacterial communities with different diversity traits and employed exoenzyme activities (EEAs) and carbon acquisition potential (CAP) from substrates as proxies of bacterial functioning to test the independent effects of these two aspects of biodiversity. We expected that metabolic diversity, but not phylogenetic diversity would be associated with greater ecological function.

Impacts of predator-mediated interactions along a climatic gradient on the population dynamics of an alpine bird.

According to classic theory, species' population dynamics and distributions are less influenced by species interactions under harsh climatic conditions compared to under more benign climatic conditions. In alpine and boreal ecosystems in Fennoscandia, the cyclic dynamics of rodents strongly affect many other species, including ground-nesting birds such as ptarmigan. According to the 'alternative prey hypothesis' (APH), the densities of ground-nesting birds and rodents are positively associated due to predator-prey dynamics and prey-switching.

Synergistic effects of long-term herbivory and previous fire on fine-scale heterogeneity of prescribed grassland burns.

Grassland and savanna ecosystems, important for both livelihoods and biodiversity conservation, are strongly affected by ecosystem drivers such as herbivory, fire, and drought. Interactions among fire, herbivores and vegetation produce complex feedbacks in these ecosystems, but these have rarely been studied in the context of fuel continuity and resultant fire heterogeneity. We carried out 36 controlled burns within replicated experimental plots that had allowed differential access by wild and domestic large herbivores since 1995 in a savanna ecosystem in Kenya.

Nutrients cause grassland biomass to outpace herbivory.

Human activities are transforming grassland biomass via changing climate, elemental nutrients, and herbivory. Theory predicts that food-limited herbivores will consume any additional biomass stimulated by nutrient inputs ('consumer-controlled'). Alternatively, nutrient supply is predicted to increase biomass where herbivores alter community composition or are limited by factors other than food ('resource-controlled').

Increasing effects of chronic nutrient enrichment on plant diversity loss and ecosystem productivity over time.

Human activities are enriching many of Earth's ecosystems with biologically limiting mineral nutrients such as nitrogen (N) and phosphorus (P). In grasslands, this enrichment generally reduces plant diversity and increases productivity. The widely demonstrated positive effect of diversity on productivity suggests a potential negative feedback, whereby nutrient-induced declines in diversity reduce the initial gains in productivity arising from nutrient enrichment.

Thresholds for ecological responses to global change do not emerge from empirical data.

To understand ecosystem responses to anthropogenic global change, a prevailing framework is the definition of threshold levels of pressure, above which response magnitudes and their variances increase disproportionately. However, we lack systematic quantitative evidence as to whether empirical data allow definition of such thresholds. Here, we summarize 36 meta-analyses measuring more than 4,600 global change impacts on natural communities.

Combined application of Bacillus sp. MN-54 and phosphorus improved growth and reduced lead uptake by maize in the lead-contaminated soil.

Lead (Pb) is considered an important environmental contaminant due to its considerable toxicity to living organisms. It can enter and accumulate in plant tissues and become part of the food chain. In the present study, individual and combined effects of Bacillus sp.

Phylogenetic and functional distinctiveness explain alien plant population responses to competition.

Several invasion hypotheses predict a positive association between phylogenetic and functional distinctiveness of aliens and their performance, leading to the idea that distinct aliens compete less with their resident communities. However, synthetic pattern relationships between distinctiveness and alien performance and direct tests of competition as the driving mechanism have not been forthcoming. This is likely because different patterns are observed at different spatial grains, because functional trait and phylogenetic information are often incomplete, and because of the need for competition experiments that measure demographic responses across a variety of alien species that vary in their distinctiveness.

Microbial processing of plant remains is co-limited by multiple nutrients in global grasslands.

Microbial processing of aggregate-unprotected organic matter inputs is key for soil fertility, long-term ecosystem carbon and nutrient sequestration and sustainable agriculture. We investigated the effects of adding multiple nutrients (nitrogen, phosphorus and potassium plus nine essential macro- and micro-nutrients) on decomposition and biochemical transformation of standard plant materials buried in 21 grasslands from four continents. Addition of multiple nutrients weakly but consistently increased decomposition and biochemical transformation of plant remains during the peak-season, concurrent with changes in microbial exoenzymatic activity.