Discovery of antimicrobial peptides clostrisin and cellulosin from Clostridium: insights into their structures, co-localized biosynthetic gene clusters, and antibiotic activity.

Antimicrobial resistance presents a substantial threat to global public health, demanding urgent attention and action. This study focuses on lanthipeptides, ribosomally encoded peptides that display significant structural diversity and hold promising potential as antibiotics. Genome mining was employed to locate biosynthetic gene clusters (BGCs) containing class II lanthipeptide synthetases encoded by lanM genes. A phylogenetic study analyzing homologous sequences of functional LanM sequences revealed a unique evolutionary clade of 17 LanM proteins associated with 12 Clostridium bacterial genomes. In silico exploration identified nine complete BGCs, including one super-cluster containing two co-localized operons from Clostridium cellulovorans 743B, that encode for two new peptides named clostrisin and cellulosin. Each operon was heterologously expressed in Escherichia coli. Molecular weights associated with the expected post-translational modifications of the purified lanthipeptide were confirmed by MS-MS/MS analysis for cellulosin, while clostrisin was not post-translationally modified. Both peptides demonstrated antimicrobial activity against multidrug-resistant bacteria, such as a clinical strain of Staphylococcus epidermidis MIQ43 and Pseudomonas aeruginosa PA14. This is the first report of lanthipeptides from the Clostridium genus produced with its native biosynthetic machinery, as well as chemically and biologically characterized. This study showcases the immense potential of genome mining in identifying new RiPP synthetases and associated bioactive peptides.

Pharmacokinetic and pharmacodynamic bioequivalence between regular human insulin (rDNA origin) in 0.9% sodium chloride ready-to-use infusion 1 U/mL and 100 U/mL concentrate diluted to 1 U/mL in healthy males.

AIM: To show pharmacokinetic (PK) and pharmacodynamic (PD) bioequivalence between Myxredlin, a novel, ready-to-use regular human insulin 1 U/mL formulation (BAX-HI), and Novolin R 100 U/mL concentrate diluted to 1 U/mL (NOVO-HI). MATERIALS AND METHODS: This phase 1, double-blind, randomized, two-way crossover study compared the PK and PD properties of BAX-HI and NOVO-HI. A total of 58 healthy males received 0.36 U/kg of each study drug, administered intravenously over a 6-hour period, concurrent with an 8-hour euglycaemic clamp at two treatment periods separated by a washout period of 7-10 days. The primary PK endpoint was the area under the insulin concentration-time curve at steady state (SS) measured from 300 to 360 minutes (AUCINS-SS 300-360 min ). The primary PD endpoint was the area under the glucose infusion rate-time curve at SS measured from 300 to 360 minutes (AUCGIR-SS 300-360 min ). RESULTS: All subjects completed the first treatment period and 54 subjects completed both treatment periods. Bioequivalence between BAX-HI and NOVO-HI was shown for the primary endpoints as the 90% confidence interval (CI) of the geometric least-squares (LS) mean ratio for AUCINS-SS 300-360 min , and the 90% CI and 95% CI of the geometric LS mean ratio for AUCGIR-SS 300-360 min were entirely contained within the prespecified limits of 80%-125%. Safety profiles were comparable for both study drugs and there were no serious adverse events. CONCLUSIONS: The study showed bioequivalence between BAX-HI and NOVO-HI in terms of PK and PD characteristics in healthy males.

Trait-based aerial dispersal of arbuscular mycorrhizal fungi.

Dispersal is a key process driving local-scale community assembly and global-scale biogeography of plant symbiotic arbuscular mycorrhizal (AM) fungal communities. A trait-based approach could improve predictions regarding how AM fungal aerial dispersal varies by species. We conducted month-long collections of aerial AM fungi for 12 consecutive months in an urban mesic environment at heights of 20 m. We measured morphological functional traits of collected spores and assessed aerial AM fungal community structure both morphologically and with high-throughput sequencing. Large numbers of AM fungal spores were present in the air over the course of one year and these spores exhibited traits that facilitate aerial dispersal. Measured aerial spores were smaller than average for Glomeromycotinan fungi. Trait-based predictions indicate that nearly 1/3 of described species from diverse genera demonstrate the potential for aerial dispersal. Diversity of aerial AM fungi was relatively high (20 spore species and 17 virtual taxa) and both spore abundance and community structure shifted temporally. The prevalence of aerial dispersal in AM fungi is perhaps greater than previously indicated and a hypothesized model of AM fungal aerial dispersal mechanisms is presented. Anthropogenic soil impacts may liberate AM fungal propagules initiating the dispersal of ruderal species.

Myristate and the ecology of AM fungi: significance, opportunities, applications and challenges.

A recent study by Sugiura and coworkers reported the non-symbiotic growth and spore production of an arbuscular mycorrhizal (AM) fungus, Rhizophagus irregularis, when the fungus received an external supply of certain fatty acids, myristates (C:14). This discovery follows the insight that AM fungi receive fatty acids from their hosts when in symbiosis. If this result holds up and can be repeated under nonsterile conditions and with a broader range of fungi, it has numerous consequences for our understanding of AM fungal ecology, from the level of the fungus, at the plant community level, and to functional consequences in ecosystems. In addition, myristate may open up several avenues from a more applied perspective, including improved fungal culture and supplementation of AM fungi or inoculum in the field. We here map these potential opportunities, and additionally offer thoughts on potential risks of this potentially new technology. Lastly, we discuss the specific research challenges that need to be overcome to come to an understanding of the potential role of myristate in AM ecology.

The relative importance of ecological drivers of arbuscular mycorrhizal fungal distribution varies with taxon phylogenetic resolution.

The phylogenetic depth at which arbuscular mycorrhizal (AM) fungi harbor a coherent ecological niche is unknown, which has consequences for operational taxonomic unit (OTU) delineation from sequence data and the study of their biogeography. We tested how changes in AM fungi community composition across habitats (beta diversity) vary with OTU phylogenetic resolution. We inferred exact sequence variants (ESVs) to resolve phylotypes at resolutions finer than provided by traditional sequence clustering and analyzed beta diversity profiles up to order-level sequence clusters. At the ESV level, we detected the environmental predictors revealed with traditional OTUs or at higher genetic distances. However, the correlation between environmental predictors and community turnover steeply increased at a genetic distance of c. 0.03 substitutions per site. Furthermore, we observed a turnover of either closely or distantly related taxa (respectively at or above 0.03 substitutions per site) along different environmental gradients. This study suggests that different axes of AM fungal ecological niche are conserved at different phylogenetic depths. Delineating AM fungal phylotypes using DNA sequences should screen different phylogenetic resolutions to better elucidate the factors that shape communities and predict the fate of AM symbioses in a changing environment.

Sensorless FOC Performance Improved with On-Line Speed and Rotor Resistance Estimator Based on an Artificial Neural Network for an Induction Motor Drive.

Three-phase induction motor drive requires high accuracy in high performance processes in industrial applications. Field oriented control, which is one of the most employed control schemes for induction motors, bases its function on the electrical parameter estimation coming from the motor. These parameters make an electrical machine driver work improperly, since these electrical parameter values change at low speeds, temperature changes, and especially with load and duty changes. The focus of this paper is the real-time and on-line electrical parameters with a CMAC-ADALINE block added in the standard FOC scheme to improve the IM driver performance and endure the driver and the induction motor lifetime. Two kinds of neural network structures are used; one to estimate rotor speed and the other one to estimate rotor resistance of an induction motor.

Aligning spatial ecological theory with the study of clonal organisms: the case of fungal coexistence.

Established ecological theory has focused on unitary organisms, and thus its concepts have matured into a form that often hinders rather than facilitates the ecological study of modular organisms. Here, we use the example of filamentous fungi to develop concepts that enable integration of non-unitary (modular) organisms into the established community ecology theory, with particular focus on its spatial aspects. In doing so, we provide a link between fungal community ecology and modern coexistence theory (MCT). We first show how community processes and predictions made by MCT can be used to define meaningful scales in fungal ecology. This leads to the novel concept of the unit of community interactions (UCI), a promising conceptual tool for applying MCT to communities of modular organisms with indeterminate clonal growth and hierarchical individuality. We outline plausible coexistence mechanisms structuring fungal communities, and show at what spatial scales and in what habitats they are most likely to act. We end by describing challenges and opportunities for empirical and theoretical research in fungal competitive coexistence.

Advances in diffusion MRI acquisition and processing in the Human Connectome Project.

The Human Connectome Project (HCP) is a collaborative 5-year effort to map human brain connections and their variability in healthy adults. A consortium of HCP investigators will study a population of 1200 healthy adults using multiple imaging modalities, along with extensive behavioral and genetic data. In this overview, we focus on diffusion MRI (dMRI) and the structural connectivity aspect of the project. We present recent advances in acquisition and processing that allow us to obtain very high-quality in-vivo MRI data, whilst enabling scanning of a very large number of subjects. These advances result from 2 years of intensive efforts in optimising many aspects of data acquisition and processing during the piloting phase of the project. The data quality and methods described here are representative of the datasets and processing pipelines that will be made freely available to the community at quarterly intervals, beginning in 2013.

Racial and ethnic variation in referral times for thoracic oncologic surgery in a major metropolitan area.

OBJECTIVE: The study objective was to understand the impact of race/ethnicity on access to thoracic surgical care for patients undergoing lung resection for cancer. METHODS: We performed a retrospective analysis on 206 consecutive patients who underwent lung resection for cancer (120 female, 86 male; median age 66 years), with respect to how race and ethnicity impact time to referral for thoracic surgery to a major healthcare center. Time between initial radiographic appearance of a lung nodule/mass 1 cm or greater to surgical referral and time from surgical referral to operation were evaluated for 121 White, 30 Asian, 26 Hispanic, 12 African American, and 17 mixed or other race patients. The impact of age, sex, median income of patient's household, national and state Area Deprivation Indices, insurance type, and distance between the patient's domicile and our hospital was evaluated. The influence of the referring physician's practice (hospital-based, hospital-affiliated, or private), internal or external referral, race/ethnicity, and level of specialization was also studied. RESULTS: African American, Asian, Hispanic, and mixed/other race patients had significantly longer wait times between initial radiographic finding of a lung nodule/mass 1 cm or greater and surgical referral compared with White individuals (median days: African American, 78; Asian, 95; Hispanic, 92; mixed or other, 65; White, 35). Multiple linear regression analysis demonstrated that race/ethnicity was the only significant predictor of prolonged time to surgical referral when adjusted for age, sex, median household income level, national and state Area Deprivation Indices, insurance type, and distance between patient's home and our hospital. The referring physician's type of practice and internal versus external referral were not significant. However, the physician's race/ethnicity and level of specialization had an impact on referral times, with nonspecialists referring patients sooner to thoracic surgery compared with specialists who ordered more workup tests. For all patient races/ethnicities, there was no difference in time between surgical referral and day of operation. CONCLUSIONS: Race and ethnicity have a major impact on the time from initial radiographic appearance of a lung nodule/mass 1 cm or greater to referral for surgical resection for cancer. This study suggests the need to develop strategies to reduce minority wait times and improve timely access to surgery for patients with thoracic malignancies. VIDEO ABSTRACT: Discussion of how race and ethnicity impact referral time to thoracic surgery discussed by Dr Moises Hernandez.

Adipose tissue measurement in clinical research for obesity, type 2 diabetes and NAFLD/NASH.

INTRODUCTION: Excess body fat is linked to higher risks for metabolic syndrome, type 2 diabetes mellitus (T2DM), and cardiovascular disease (CV), among other health conditions. However, it is not only the level but also the distribution of body fat that contributes to increased disease risks. For example, an increased level of abdominal fat, or visceral adipose tissue (VAT), is associated with a higher risk of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). METHODS: A review of the most relevant primary and secondary sources on body composition from the last 25 years was conducted. Relevant articles were identified using PUBMED and Google Scholar. Narrative synthesis was performed as statistical pooling was not possible due to the heterogeneous nature of the studies. RESULTS: The body mass index (BMI) is commonly used as a proxy measure of body fatness. However, BMI does not reflect the level and distribution of body fat. Other anthropometric methods such as waist circumference measurement and waist-hip ratio, as well as methodologies like hydro densitometry, bioelectrical impedance, and isotope dilution are also limited in their ability to determine body fat distribution. Imaging techniques to define body composition have greatly improved performance over traditional approaches. Ultrasound (US), computed tomography (CT), dual-energy X-ray absorptiometry (DXA), magnetic resonance imaging (MRI), are now commonly used in clinical research. Of these, MRI can provide the most accurate and high-resolution measure of body composition. In addition, MRI techniques are considered the best for the determination of fat at the organ level. On the other hand, imaging modalities require specialized, often expensive equipment and expert operation. CONCLUSIONS: Anthropometric methods are suitable for rapid, high-volume screening of subjects but do not provide information on body fat distribution. Imaging techniques are more accurate but are expensive and do not lend themselves for high throughput. Therefore, successful trial strategies require a tiered approach in which subjects are first screened using anthropometric methods followed by more sophisticated modalities during the execution of the trial. This article provides a brief description of the most clinically relevant adipose tissue measurement techniques and discusses their value in obesity, diabetes, and NAFLD/NASH clinical research.

JAGGED-NOTCH3 signaling in vascular remodeling in pulmonary arterial hypertension.

Within the pulmonary arterial tree, the NOTCH3 pathway is crucial in controlling vascular smooth muscle cell proliferation and maintaining smooth muscle cells in an undifferentiated state. Pulmonary arterial hypertension (PAH) is a fatal disease without cure, characterized by elevated pulmonary vascular resistance due to vascular smooth muscle cell proliferation in precapillary arteries, perivascular inflammation, and asymmetric neointimal hyperplasia. Here, we show that human PAH is characterized by overexpression of the NOTCH ligand JAGGED-1 (JAG-1) in small pulmonary artery smooth muscle cells and that JAG-1 selectively controls NOTCH3 signaling and cellular proliferation in an autocrine fashion. In contrast, the NOTCH ligand DELTA-LIKE 4 is minimally expressed in small pulmonary artery smooth muscle cells from individuals with PAH, inhibits NOTCH3 cleavage and signaling, and retards vascular smooth muscle cell proliferation. A new monoclonal antibody for the treatment of PAH, which blocks JAG-1 cis- and trans-induced cleavage of the NOTCH3 receptor in the pulmonary vasculature, was developed. Inhibition of JAG-1-induced NOTCH3 signaling in the lung reverses clinical and pathologic pulmonary hypertension in two rodent models of disease, without toxic side effects associated with nonspecific NOTCH inhibitors. Our data suggest opposing roles of NOTCH ligands in the pulmonary vasculature in pulmonary hypertension. We propose that selectively targeting JAG-1 activation of NOTCH3 may be an effective, safe strategy to treat PAH.

A Randomized, Single Ascending Dose Study to Assess the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of a Novel Insulin Dimer.

Insulin molecules of size much greater than natural insulin have been synthesized and studied with the intention of widening the therapeutic window between adequate glycemic control and hypoglycemia as compared with conventional insulins. MK-1092 is a synthetic insulin dimer with favorable properties demonstrated in preclinical studies. Here, we report the results of the first-in-human, randomized, double-blind, active-control, single ascending dose trial of MK-1092, conducted in healthy adults, adults with type 1 diabetes (T1D), and adults with type 2 diabetes (T2D). MK-1092 was well tolerated in all study populations, and no dose-related adverse events were identified across the evaluated dose range (4-64 nmol/kg). Circulating concentrations of MK-1092 were approximately dose-proportional. Maximum glucose infusion rate (GIR) and 24-hour time-weighted average GIR were evaluated under euglycemic clamp conditions. These pharmacodynamic measurements were approximately dose-proportional in all study populations; at similar doses, the GIR parameters were lower in adults with T2D than in healthy adults or adults with T1D, likely due to the influence of insulin resistance. At doses ≥ 16 nmol/kg, MK-1092 had similar or greater effects than glargine 3 nmol/kg (0.5 units/kg) on increasing GIR in each study population and on suppressing free fatty acids and ketone generation in adults with T1D. MK-1092 did not prevent a subsequent high dose of lispro from increasing the GIR in healthy adults. Additional studies in adults with T1D and T2D are needed to further evaluate the safety, tolerability, and efficacy profile of MK-1092 and its potential for differentiation from more conventional insulins. (ClinicalTrials.gov: NCT03170544).

Multifocal Calcifying Fibrous Tumor at Seven Intrathoracic Sites in One Patient.

Calcifying fibrous tumors are rare lesions that occur throughout the body. A 35-year-old man presented with exertional dyspnea. Computed tomography showed a polypoid mass abutting pericardium, diaphragm, and left chest wall, and a pleural-based lesion adjacent to T12. Thoracoscopy revealed a large mass with diaphragmatic stalk, two pleural-based nodules, and four diaphragmatic nodules. Pathologic analysis of resected lesions showed calcifying fibrous tumors. Three lesions contained heterogenous mutations associated with this tumor type. The patient is disease free 1 year later. Calcifying fibrous tumors should be recognized as rare multifocal pleural and diaphragmatic-based tumors. Complete resection leads to excellent survival for patients with this uncommon disease.

Upregulation of Calcium Homeostasis Modulators in Contractile-To-Proliferative Phenotypical Transition of Pulmonary Arterial Smooth Muscle Cells.

Excessive pulmonary artery (PA) smooth muscle cell (PASMC) proliferation and migration are implicated in the development of pathogenic pulmonary vascular remodeling characterized by concentric arterial wall thickening and arteriole muscularization in patients with pulmonary arterial hypertension (PAH). Pulmonary artery smooth muscle cell contractile-to-proliferative phenotypical transition is a process that promotes pulmonary vascular remodeling. A rise in cytosolic Ca2+ concentration [(Ca2+) cyt ] in PASMCs is a trigger for pulmonary vasoconstriction and a stimulus for pulmonary vascular remodeling. Here, we report that the calcium homeostasis modulator (CALHM), a Ca2+ (and ATP) channel that is allosterically regulated by voltage and extracellular Ca2+, is upregulated during the PASMC contractile-to-proliferative phenotypical transition. Protein expression of CALHM1/2 in primary cultured PASMCs in media containing serum and growth factors (proliferative PASMC) was significantly greater than in freshly isolated PA (contractile PASMC) from the same rat. Upregulated CALHM1/2 in proliferative PASMCs were associated with an increased ratio of pAKT/AKT and pmTOR/mTOR and an increased expression of the cell proliferation marker PCNA, whereas serum starvation and rapamycin significantly downregulated CALHM1/2. Furthermore, CALHM1/2 were upregulated in freshly isolated PA from rats with monocrotaline (MCT)-induced PH and in primary cultured PASMC from patients with PAH in comparison to normal controls. Intraperitoneal injection of CGP 37157 (0.6 mg/kg, q8H), a non-selective blocker of CALHM channels, partially reversed established experimental PH. These data suggest that CALHM upregulation is involved in PASMC contractile-to-proliferative phenotypical transition. Ca2+ influx through upregulated CALHM1/2 may play an important role in the transition of sustained vasoconstriction to excessive vascular remodeling in PAH or precapillary PH. Calcium homeostasis modulator could potentially be a target to develop novel therapies for PAH.

Adult Stem Cell-derived Complete Lung Organoid Models Emulate Lung Disease in COVID-19.

SARS-CoV-2, the virus responsible for COVID-19, causes widespread damage in the lungs in the setting of an overzealous immune response whose origin remains unclear. We present a scalable, propagable, personalized, cost-effective adult stem cell-derived human lung organoid model that is complete with both proximal and distal airway epithelia. Monolayers derived from adult lung organoids (ALOs), primary airway cells, or hiPSC-derived alveolar type-II (AT2) pneumocytes were infected with SARS-CoV-2 to create in vitro lung models of COVID-19. Infected ALO-monolayers best recapitulated the transcriptomic signatures in diverse cohorts of COVID-19 patient-derived respiratory samples. The airway (proximal) cells were critical for sustained viral infection whereas distal alveolar differentiation (AT2→AT1) was critical for mounting the overzealous host immune response in fatal disease; ALO monolayers with well-mixed proximodistal airway components recapitulated both. Findings validate a human lung model of COVID-19 which can be immediately utilized to investigate COVID-19 pathogenesis, and vet new therapies and vaccines.

Adult stem cell-derived complete lung organoid models emulate lung disease in COVID-19.

Background: SARS-CoV-2, the virus responsible for COVID-19, causes widespread damage in the lungs in the setting of an overzealous immune response whose origin remains unclear. Methods: We present a scalable, propagable, personalized, cost-effective adult stem cell-derived human lung organoid model that is complete with both proximal and distal airway epithelia. Monolayers derived from adult lung organoids (ALOs), primary airway cells, or hiPSC-derived alveolar type II (AT2) pneumocytes were infected with SARS-CoV-2 to create in vitro lung models of COVID-19. Results: Infected ALO monolayers best recapitulated the transcriptomic signatures in diverse cohorts of COVID-19 patient-derived respiratory samples. The airway (proximal) cells were critical for sustained viral infection, whereas distal alveolar differentiation (AT2→AT1) was critical for mounting the overzealous host immune response in fatal disease; ALO monolayers with well-mixed proximodistal airway components recapitulated both. Conclusions: Findings validate a human lung model of COVID-19, which can be immediately utilized to investigate COVID-19 pathogenesis and vet new therapies and vaccines. Funding: This work was supported by the National Institutes for Health (NIH) grants 1R01DK107585-01A1, 3R01DK107585-05S1 (to SD); R01-AI141630, CA100768 and CA160911 (to PG) and R01-AI 155696 (to PG, DS and SD); R00-CA151673 and R01-GM138385 (to DS), R01- HL32225 (to PT), UCOP-R00RG2642 (to SD and PG), UCOP-R01RG3780 (to P.G. and D.S) and a pilot award from the Sanford Stem Cell Clinical Center at UC San Diego Health (P.G, S.D, D.S). GDK was supported through The American Association of Immunologists Intersect Fellowship Program for Computational Scientists and Immunologists. L.C.A's salary was supported in part by the VA San Diego Healthcare System. This manuscript includes data generated at the UC San Diego Institute of Genomic Medicine (IGC) using an Illumina NovaSeq 6000 that was purchased with funding from a National Institutes of Health SIG grant (#S10 OD026929).

Interactions between adenosine and K+ channel-related pathways in the coupling of somatosensory activation and pial arteriolar dilation.

Multiple, perhaps interactive, mechanisms participate in the linkage between increased neural activity and cerebral vasodilation. In the present study, we assessed whether neural activation-related pial arteriolar dilation (PAD) involved interactions among adenosine (Ado) A(2) receptors (A(2)Rs), large-conductance Ca(2+)-operated K(+) (BK(Ca)) channels, and inward rectifier K(+) (K(ir)) channels. In rats with closed cranial windows, we monitored sciatic nerve stimulation (SNS)-induced PAD in the absence or presence of pharmacological blockade of A(2)Rs (ZM-241385), ecto-5'-nucleotidase (α,ß-methylene-adenosine diphosphate), BK(Ca) channels (paxilline), and K(ir) channels (BaCl(2)). Individually, these interventions led to 53-66% reductions in SNS-induced PADs. Combined applications of these blockers led to little or no further repression of SNS-induced PADs, suggesting interactions among A(2)Rs and K(+) channels. In the absence of SNS, BaCl(2) blockade of K(ir) channels produced 52-80% reductions in Ado and NS-1619 (BK(Ca) channel activator)-induced PADs. In contrast, paxilline blockade of BK(Ca) channels was without effect on dilations elicited by KCl (K(ir) channel activator) and Ado suffusions, indicating that Ado- and NS-1619-associated PADs involved K(ir) channels. In addition, targeted ablation of the superficial glia limitans was associated with a selective 60-80% loss of NS-1619 responses, suggesting that the BK(Ca) channel participation (and paxilline sensitivity) derived largely from channels within the glia limitans. Additionally, blockade of either PKA or adenylyl cyclase caused markedly attenuated pial arteriolar responses to SNS and, in the absence of SNS, responses to Ado, KCl, and NS-1619. These findings suggested a key, possibly permissive, role for A(2)R-linked cAMP generation and PKA-induced K(+) channel phosphorylation in somatosensory activation-evoked PAD.

Acute effects of 2-methoxyestradiol on endothelial aortic No release in male and ovariectomized female rats.

The endogenous metabolites of 17beta-estradiol are thought to have protective vascular effects, especially in males and estrogen-deprived females. The present study evaluated the acute in vitro effects of the active metabolite 2-methoxyestradiol on endothelial NO release from ovariectomized female and intact male and female rat aortas. NO was measured electrochemically by differential normal pulse amperometry using carbon fiber microsensors, and also by fluorescence microscopy using 4,5-diaminofluorescein diacetate. 2-Methoxyestradiol alone induced a maintained increase in endothelial NO release in male and ovariectomized rats that was reduced by pretreatment with L-NAME. NO release induced by calcium ionophore alone (A23187) was lower in aortas from ovariectomized rats than from intact females, indicating that estrogen deprivation induces endothelial dysfunction. Pretreatment of aortas with 2-methoxyestradiol potentiated significantly the A23187-induced-NO release in ovariectomized as well as in males, but not in intact females. This potentiation was reduced or abolished by L-NAME. 2-Methoxyestradiol potentiated the vasodilatory effect of A23187 on intestinal arterioles, and also increased intestinal tissular laser-Doppler blood flow signal. These results demonstrate that 17beta-estradiol and its active metabolite 2-methoxyestradiol increase basal aortic endothelial NO production and also cause a potentiation of the calcium ionophore-stimulated NO release in male and ovariectomized, while it has no effects on intact females. 2-Methoxyestradiol appears to be a promising pharmacological agent capable of improving endothelial function in men and postmenopausal women.

Nitrogen Type and Availability Drive Mycorrhizal Effects on Wheat Performance, Nitrogen Uptake and Recovery, and Production Sustainability.

Plant performance is strongly dependent on nitrogen (N), and thus increasing N nutrition is of great relevance for the productivity of agroecosystems. The effects of arbuscular mycorrhizal (AM) fungi on plant N acquisition are debated because contradictory results have been reported. Using 15N-labeled fertilizers as a tracer, we evaluated the effects of AM fungi on N uptake and recovery from mineral or organic sources in durum wheat. Under sufficient N availability, AM fungi had no effects on plant biomass but increased N concentrations in plant tissue, plant N uptake, and total N recovered from the fertilizer. In N-deficient soil, AM fungi led to decreased aboveground biomass, which suggests that plants and AM fungi may have competed for N. When the organic source had a low C:N ratio, AM fungi favored both plant N uptake and N recovery. In contrast, when the organic source had a high C:N ratio, a clear reduction in N recovery from the fertilizer was observed. Overall, the results indicate an active role of arbuscular mycorrhizae in favoring plant N-related traits when N is not a limiting factor and show that these fungi help in N recovery from the fertilizer. These results hold great potential for increasing the sustainability of durum wheat production.

Soil Saprobic Fungi Differ in Their Response to Gradually and Abruptly Delivered Copper.

The overwhelming majority of studies examining environmental change deliver treatments abruptly, although, in fact, many important changes are gradual. One example of a gradually increasing environmental stressor is heavy metal contamination. Essential heavy metals, such as copper, play an important role within cells of living organisms but are toxic at higher concentrations. In our study, we focus on the effects of copper pollution on filamentous soil fungi, key players in terrestrial ecosystem functioning. We hypothesize that fungi exposed to gradually increasing copper concentrations have higher chances for physiological acclimation and will maintain biomass production and accumulate less copper, compared to fungi abruptly exposed to the highest copper concentration. To test this hypothesis, we conducted an experiment with 17 fungal isolates exposed to gradual and abrupt copper addition. Contrary to our hypothesis, we find diverse idiosyncratic responses, such that for many fungi gradually increasing copper concentrations have more severe effects (stronger growth inhibition and higher copper accumulation) than an abrupt increase. While a number of environmental change studies have accumulated evidence based on the magnitude of changes, the results of our study imply that the rate of change can be an important factor to consider in future studies in ecology, environmental science, and environmental management.