Evidence Implicating Blood-Brain Barrier Impairment in the Pathogenesis of Acquired Epilepsy following Acute Organophosphate Intoxication.

Organophosphate (OP) poisoning can trigger cholinergic crisis, a life-threatening toxidrome that includes seizures and status epilepticus. These acute toxic responses are associated with persistent neuroinflammation and spontaneous recurrent seizures (SRS), also known as acquired epilepsy. Blood-brain barrier (BBB) impairment has recently been proposed as a pathogenic mechanism linking acute OP intoxication to chronic adverse neurologic outcomes. In this review, we briefly describe the cellular and molecular components of the BBB, review evidence of altered BBB integrity following acute OP intoxication, and discuss potential mechanisms by which acute OP intoxication may promote BBB dysfunction. We highlight the complex interplay between neuroinflammation and BBB dysfunction that suggests a positive feedforward interaction. Lastly, we examine research from diverse models and disease states that suggest mechanisms by which loss of BBB integrity may contribute to epileptogenic processes. Collectively, the literature identifies BBB impairment as a convergent mechanism of neurologic disease and justifies further mechanistic research into how acute OP intoxication causes BBB impairment and its role in the pathogenesis of SRS and potentially other long-term neurologic sequelae. Such research is critical for evaluating BBB stabilization as a neuroprotective strategy for mitigating OP-induced epilepsy and possibly seizure disorders of other etiologies. SIGNIFICANCE STATEMENT: Clinical and preclinical studies support a link between blood-brain barrier (BBB) dysfunction and epileptogenesis; however, a causal relationship has been difficult to prove. Mechanistic studies to delineate relationships between BBB dysfunction and epilepsy may provide novel insights into BBB stabilization as a neuroprotective strategy for mitigating epilepsy resulting from acute organophosphate (OP) intoxication and non-OP causes and potentially other adverse neurological conditions associated with acute OP intoxication, such as cognitive impairment.

Selective Neuronal Knockout of STAT3 Function Inhibits Epilepsy Progression, Improves Cognition, and Restores Dysregulated Gene Networks in a Temporal Lobe Epilepsy Model.

OBJECTIVE: Temporal lobe epilepsy (TLE) is a progressive disorder mediated by pathological changes in molecular cascades and hippocampal neural circuit remodeling that results in spontaneous seizures and cognitive dysfunction. Targeting these cascades may provide disease-modifying treatments for TLE patients. Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) inhibitors have emerged as potential disease-modifying therapies; a more detailed understanding of JAK/STAT participation in epileptogenic responses is required, however, to increase the therapeutic efficacy and reduce adverse effects associated with global inhibition. METHODS: We developed a mouse line in which tamoxifen treatment conditionally abolishes STAT3 signaling from forebrain excitatory neurons (nSTAT3KO). Seizure frequency (continuous in vivo electroencephalography) and memory (contextual fear conditioning and motor learning) were analyzed in wild-type and nSTAT3KO mice after intrahippocampal kainate (IHKA) injection as a model of TLE. Hippocampal RNA was obtained 24 h after IHKA and subjected to deep sequencing. RESULTS: Selective STAT3 knock-out in excitatory neurons reduced seizure progression and hippocampal memory deficits without reducing the extent of cell death or mossy fiber sprouting induced by IHKA injection. Gene expression was rescued in major networks associated with response to brain injury, neuronal plasticity, and learning and memory. We also provide the first evidence that neuronal STAT3 may directly influence brain inflammation. INTERPRETATION: Inhibiting neuronal STAT3 signaling improved outcomes in an animal model of TLE, prevented progression of seizures and cognitive co-morbidities while rescuing pathogenic changes in gene expression of major networks associated with epileptogenesis. Specifically targeting neuronal STAT3 may be an effective disease-modifying strategy for TLE. ANN NEUROL 2023;94:106-122.

Role of the nonribosomal peptide synthetase siderophore enzyme (Rfs) of Mucor lusitanicus in controlling the growth of fungal phytopathogens.

Dimorphic species of Mucor, which are cosmopolitan fungi belonging to subphylum Mucoromycotina, are metabolically versatile. Some species of Mucor are sources of biotechnological products, such as biodiesel from Mucor circinelloides and expression of heterologous proteins from Mucor lusitanicus. Furthermore, Mucor lusitanicus has been described as a model for understanding mucormycosis infections. However, little is known regarding the relationship between Mucor lusitanicus and other soil inhabitants. In this study, we investigated the potential use of Mucor lusitanicus as a biocontrol agent against fungal phytopathogens, namely Fusarium oxysporum f. sp. lycopersici, Fusarium solani, and Alternaria solani, which destroy economically important crops. Results showed that aerobic cell-free supernatants of the culture broth (SS) from Mucor lusitanicus inhibited the growth of the fungal phytopathogens in culture, soil, and tomato fruits. The SS obtained from a strain of Mucor lusitanicus carrying the deletion of rfs gene, which encodes an enzyme involved in the synthesis of siderophore rhizoferrin, had a decreased inhibitory effect against the growth of the phytopathogens. Contrarily, this inhibitory effect was more evident with the SS from an rfs-overexpressing strain compared to the wild-type. This study provides a framework for the potential biotechnological use of the molecules secreted from Mucor lusitanicus in the biocontrol of fungal phytopathogens.

Real Time Water-In-Oil Emulsion Size Measurement in Optofluidic Channels.

In this work, we investigated a platform for real-time emulsion droplet detection and size measurement in optofluidic platforms. An 8.2 µm core diameter input optical fiber and a multi-mode Gradient Refractive Index (GRIN) output fiber were integrated into an acrylic microfluidic channel platform consisting of three layers. Water-in-oil emulsions were investigated, since relevant applications have emerged in the recent past for these types of emulsions, such as drug encapsulation as well as droplet-based Polymerase Chain Reaction (PCR) amplification of DNA, among others. The main contribution of this work is in understanding the main physical phenomena (i.e., total internal reflection, refraction, and interference) behind the complex transmittance pattern obtained for these droplets. For this purpose, a frequency domain electromagnetic wave propagation modelling of the structure using the Finite Element Method (FEM) was used along with experimental measurements.

Down-regulation of AMPA receptors and long-term potentiation during early epileptogenesis.

Epilepsy is a brain disorder characterized by the occurrence of recurrent spontaneous seizures. Behavioral disorders and altered cognition are frequent comorbidities affecting the quality of life of people with epilepsy. These impairments are undoubtedly multifactorial and the specific mechanisms underlying these comorbidities are largely unknown. Long-lasting alterations in synaptic strength due to changes in expression, phosphorylation, or function of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors (AMPARs) have been associated with alterations in neuronal synaptic plasticity. In particular, alterations in hippocampal long-term potentiation (LTP), a well-accepted model of learning and memory, have been associated with altered cognition in epilepsy. Here, we analyzed the effects of pilocarpine-induced status epilepticus (SE) on AMPARs to determine if alterations in AMPAR signaling might be one of the mechanisms contributing to altered cognition during epilepsy. We found alterations in the phosphorylation and plasma membrane expression of AMPARs. In addition, we detected altered expression of GRIP, a key scaffolding protein involved in the proper distribution of AMPARs at the neuronal cell surface. Interestingly, a functional analysis revealed that these molecular changes are linked to impaired LTP. Together, these observations suggest that seizure-induced alterations in the molecular machinery regulating AMPARs likely impact the neuron's ability to support synaptic plasticity that is required for learning and memory.

Transcript pattern analysis of Arf-family genes in the phytopathogen Fusarium oxysporum f. sp. lycopersici reveals the role of Arl3 in the virulence.

Fusarium oxysporum f. sp. lycopersici is an important plant pathogen that has been used to understand the virulence mechanisms that soil inhabiting fungi exhibit during the infection process. In F. oxysporum many of the virulence factors are secreted, and the secretion process requires the formation of vesicles. Arf family members, represented by Arf (ADP- Ribosylation Factor), Arl (Arf-like), and Sar (Secretion-associated and Ras-related) proteins, are involved in the vesicle creation process. In this study we identified the Arf family members in F. oxysporum f. sp. lycopersici, which includes seven putative proteins: Arf1, Arf3, Arl1 through Arl3, Arl8B, and Sar1. Quantification of the mRNA levels of each arf encoding gene revealed that the highest expression corresponds to arf1 in all tested conditions. The phylogenetic analysis revealed that no other Arf1 paralogue, such as Arf2 from yeast, is present in F. oxysporum f. sp. lycopersici. The essential function suggested of Arf1 in F. oxysporum f. sp. lycopersici was corroborated experimentally when, after several attempts, it was impossible to obtain a knockout mutant in arf1. Moreover, arl3 mRNA levels increased significantly when plant tissue was added as a sole carbon source, suggesting that the product of these genes could play pivotal roles during plant infection, the corresponding mutant ∆arl3 was less virulent compared to the wild-type strain. These results describe the role of arl3 as a critical regulator of the virulence in F. oxysporum f. sp. lycopersici and stablish a framework for the arf family members to be studied in deeper details in this phytopathogen.

Alteration of Fermentative Metabolism Enhances Mucor circinelloides Virulence.

The fungus Mucor circinelloides undergoes yeast-mold dimorphism, a developmental process associated with its capability as a human opportunistic pathogen. Dimorphism is strongly influenced by carbon metabolism, and hence the type of metabolism likely affects fungus virulence. We investigated the role of ethanol metabolism in M. circinelloides virulence. A mutant in the adh1 gene (M5 strain) exhibited higher virulence than the wild-type (R7B) and the complemented (M5/pEUKA-adh1+) strains, which were nonvirulent when tested in a mouse infection model. Cell-free culture supernatant (SS) from the M5 mutant showed increased toxic effect on nematodes compared to that from R7B and M5/pEUKA-adh1+ strains. The concentration of acetaldehyde excreted by strain M5 in the SS was higher than that from R7B, which correlated with the acute toxic effect on nematodes. Remarkably, strain M5 showed higher resistance to H2O2, resistance to phagocytosis, and invasiveness in mouse tissues and induced an enhanced systemic inflammatory response compared with R7B. The mice infected with strain M5 under disulfiram treatment exhibited only half the life expectancy of those infected with M5 alone, suggesting that acetaldehyde produced by M. circinelloides contributes to the toxic effect in mice. These results demonstrate that the failure in fermentative metabolism, in the step of the production of ethanol in M. circinelloides, contributes to its virulence, inducing a more severe tissue burden and inflammatory response in mice as a consequence of acetaldehyde overproduction.

Effects of a potassium channel opener on brain injury and neurologic outcomes in an animal model of neonatal hypoxic-ischemic injury.

BACKGROUND: Hypoxia-ischemia (HI) is the most common cause of brain injury in newborns and the survivors often develop cognitive and sensorimotor disabilities that undermine the quality of life. In the current study, we examined the effectiveness of flupirtine, a potassium channel opener, shown previously in an animal model to have strong anti-neonatal-seizure efficacy, to provide neuroprotection and alleviate later-life disabilities caused by neonatal hypoxic-ischemic injury. METHODS: The rats were treated with a single dose of flupirtine for 4 days following HI induction in 7-day-old rats. The first dose of flupirtine was given after the induction of HI and during the reperfusion period. The effect of treatment was examined on acute and chronic brain injury, motor functions, and cognitive abilities. RESULTS: Flupirtine treatment significantly reduced HI-induced hippocampal and cortical tissue loss at acute time point. Furthermore, at chronic time point, flupirtine reduced contralateral hippocampal volume loss and partially reversed learning and memory impairments but failed to improve motor deficits. CONCLUSION: The flupirtine treatment regimen used in the current study significantly reduced brain injury at acute time point in an animal model of neonatal hypoxic-ischemic encephalopathy. However, these neuroprotective effects were not persistent and only modest improvement in functional outcomes were observed at chronic time points.

Virulence Conferred by PumA Toxin from the Plasmid-Encoded PumAB Toxin-Antitoxin System is Regulated by Quorum System.

Toxin-antitoxin (TA) systems are small genetic elements composed of a toxin gene and its cognate antitoxin that are important for plasmid stabilization (plasmid-encoded) and bacterial virulence (chromosome-encoded). These systems are also related to biofilm and persister cell formations. Pseudomonas aeruginosa is an antibiotic-resistant human pathogen that produces virulence factors modulated by quorum sensing (QS) and can form biofilms. The type II PumAB TA system of pUM505, isolated from a clinical strain of P. aeruginosa, confers plasmid stability. Additionally, the PumA toxin increases P. aeruginosa virulence and is neutralized by the PumB antitoxin. In this study, we determined whether virulence conferred by PumA toxin is regulated by QS. The pumA gene was transferred to P. aeruginosa lasI/rhlI, a mutant strain in the LasI and RhlI QS systems, to analyze the effect on virulence of the transformants. pumA transfer did not increase bacterial virulence in lettuce and Caenorhabditis elegans, suggesting that the virulence conferred by PumA requires QS modulation. pumA mRNA levels drastically decreased in the P. aeruginosa lasI/rhlI (pUC_pumA) strain, suggesting positive regulation of pumA gene expression by QS. Supplementation of the growth medium of P. aeruginosa lasI/rhlI (pUC_pumA) with C4-AHL and 3-oxo-C12-AHL autoinducers increased pumA mRNA levels and restored bacterial virulence, suggesting that both autoinducers complemented the mutations and positively regulated the toxic effects of PumA. This strengthened the hypothesis that QS regulates bacterial virulence conferred by the PumA toxin. Thus, this report establishes an important function of QS in the virulence conferred by plasmid-encoded TA systems in bacterial pathogens.

Calpain activation and neuronal death during early epileptogenesis.

Epilepsy is a brain disorder characterized by a predisposition to suffer epileptic seizures. Acquired epilepsy might be the result of brain insults like head trauma, stroke, brain infection, or status epilepticus (SE) when one of these triggering injuries starts a transformative process known as epileptogenesis. There is some data to suggest that, during epileptogenesis, seizures themselves damage the brain but there is no conclusive evidence to demonstrate that spontaneous recurrent seizures themselves injure the brain. Our recent evidence indicates that calpain overactivation might be relevant for epileptogenesis. Here, we investigated if spontaneous recurrent seizures that occur during an early period of epileptogenesis show any correlation with the levels of calpain activation and/or expression. In addition, we also investigated a possible association between the occurrence of spontaneous seizures and increased levels of cell death, gliosis and inflammation (typical markers associated with epileptogenesis). We found that the number of spontaneous seizures detected prior to sample collection was correlated with altered calpain activity and expression. Moreover, the levels of hippocampal neurodegeneration were also correlated with seizure occurrence. Our findings suggest that, at least during early epileptogenesis, there is a correlation between seizure occurrence, calpain activity and neurodegeneration. Thus, this study opens the possibility that aberrant calpain reactivation by spontaneous seizures might contribute to the manifestation of future spontaneous seizures.

Role of Arf-like proteins (Arl1 and Arl2) of Mucor circinelloides in virulence and antifungal susceptibility.

Mucor circinelloides is an etiologic agent of mucormycosis, a fungal infection produced by Mucorales often associated with mortality due to unavailability of antifungal drugs. Arl proteins belong to the Arf family and are involved in vesicle trafficking and tubulin assembly. This study identified two Arl (Arf-like)-encoding genes, arl1 and arl2, in M. circinelloides and explored their function in morphogenesis, virulence, and antifungal susceptibility. Although Arl1 and Arl2 proteins shared 55% amino acid sequence identity, arl1 and arl2 genes showed distinct transcriptional expression patterns. arl1 was expressed at higher levels than arl2 and induced in mycelia, suggesting a role in morphological transitions. Disruption of the arl1 and arl2 genes led to heterokaryon (Δarl1(+)(-)) and homokaryon (Δarl2) genotypes, respectively. The incapacity to generate homokaryon mutants for arl1 suggested that it is essential for growth of M. circinelloides. Deletion of each gene reduced the expression of the other, suggesting the existence of a positive cross-regulation between them. Thus, deletion of arl2 resulted in a ~60% reduction of arl1 expression, whereas the Δarl1(+)(-) showed ∼90% reduction of arl1 expression. Mutation of arl2 showed no phenotype or a mild phenotype between Δarl1(+)(-) and wild-type (WT), suggesting that all observed phenotypes in both mutant strains corresponded to arl1 low expression. The Δarl1(+)(-) produced a small amount of spores that showed increased sensitivity to dodecyl-sulfate and azoles, suggesting a defect in the cell wall that was further supported by decrease in saccharide content. These defects in the cell wall were possibly originated by abnormal vesicle trafficking since FM4-64 staining of both mutants Δarl1(+)(-) and Δarl2 revealed less well-localized endosomes compared to the WT. Moreover, aberrant vesicle trafficking may be responsible for the secretion of specific virulence-related proteins since cell-free medium from Δarl1(+)(-) were found to increase killing of Caenorhabditis elegans compared to WT.

Low-loss pedestal Ta2O5 nonlinear optical waveguides.

In this work, we investigate a pedestal tantalum oxide (Ta2O5) material platform for integrated nonlinear optics (NLO). In order to achieve low propagation losses with this material, pedestal waveguides with Ta2O5 cores were designed. The nonlinear refractive index n2 of this new platform was obtained by measuring the amount of spectral broadening due to self-phase modulation (SPM) of 23 fs optical pulses at 785 nm propagating through the waveguides. In this manner, a nonlinear index of (5.8 ± 2.0) × 10-19 m2W-1 was found for this material, which is in good agreement with values reported in related works where strip waveguides were used for a similar purpose. Furthermore, due to the pedestal configuration, propagation losses as low as 1.6 dB·cm-1 for narrow waveguides and 0.1 dB·cm-1 for large waveguides were obtained. Finite element method (FEM) mode analysis was performed to calculate the mode characteristics, as well as the effective areas of the waveguides. The high nonlinear and linear refractive indices, wide bandgap and low propagation losses make this platform ideal for applications extending from the visible into the mid-IR regions of the optical spectrum. Due the large gap, Ta2O5 should have low two photon absorption at the near-IR as well.

Sporulation on blood serum increases the virulence of Mucor circinelloides.

Mucor circinelloides is an opportunistic human pathogen that is used to study mucormycosis, a rare but lethal infection in susceptible immunosuppressed patients. However, the virulence characteristics of this pathogen have not been fully elucidated. In this study, sporangiospores (spores) produced on YPG medium supplemented with native blood serum increased the virulence of M. circinelloides compared with spores produced on YPG supplemented with denatured blood serum or on YPG alone. The spores produced from YPG supplemented with native blood serum increased nematode death and led to significant increases in interleukin (IL)-6, IL-1ß, macrophage inhibitory protein-2, and tumour necrosis factor α mRNA levels in liver and lung tissues from infected diabetic mice compared with those in tissues from animals infected with spores produced in the presence of YPG supplemented with denatured blood serum or of YPG alone. Moreover, spores produced from cultures supplemented with native blood serum showed increased germination rates and longer hyphae compared with other spores. The spores produced in YPG supplemented with native blood serum also enhanced resistance to stress factors and H2O2 and increased thermotolerance compared with spores produced under other conditions. In addition, spores produced in presence of blood serum increased the ability of the pathogen to survive in the presence of macrophages. Taken together, our results showed that these factors were important features for fungal virulence in humans and suggested that thermolabile components in the blood serum may induce M. circinelloides virulence.

Control of morphology and virulence by ADP-ribosylation factors (Arf) in Mucor circinelloides.

Mucor circinelloides is a dimorphic fungus used to study cell differentiation that has emerged as a model to characterize mucormycosis. In this work, we identified four ADP-ribosylation factor (Arf)-encoding genes (arf1-arf4) and study their role in the morphogenesis and virulence. Arfs are key regulators of the vesicular trafficking process and are associated with both growth and virulence in fungi. Arf1 and Arf2 share 96% identity and Arf3 and Arf4 share 89% identity, which suggests that the genes arose through gene-duplication events in M. circinelloides. Transcription analysis revealed that certain arf genes are affected by dimorphism of M. circinelloides, such as the arf2 transcript, which was accumulated during yeast development. Therefore, we created knockout mutants of four arf genes to evaluate their function in dimorphism and virulence. We found that both arf1 and arf2 are required for sporulation, but these genes also perform distinct functions; arf2 participates in yeast development, whereas arf1 is involved in aerobic growth. Conversely, arf3 and arf4 play only minor roles during aerobic growth. Moreover, we observed that all single arf-mutant strains are more virulent than the wild-type strain in mouse and nematode models, with the arf3 mutant being most virulent. Lastly, arf1/arf2 and arf3/arf4 double mutations produced heterokaryon strains that did not reach the homokaryotic state, indicating that these genes participate in essential and redundant functions. Overall, this work reveals that Arfs proteins regulate important cellular processes in M. circinelloides such as morphogenesis and virulence, laying the foundation to characterize the molecular networks underlying this regulation.

A calpain inhibitor ameliorates seizure burden in an experimental model of temporal lobe epilepsy.

In this study, we used the pilocarpine model of epilepsy to evaluate the involvement of calpain dysregulation on epileptogenesis. Detection of spectrin breakdown products (SBDPs, a hallmark of calpain activation) after induction of pilocarpine-induced status epilepticus (SE) and before appearance of spontaneous seizure suggested the existence of sustained calpain activation during epileptogenesis. Acute treatment with a cell permeable inhibitor of calpain, MDL-28170, resulted in a partial but significant reduction on seizure burden. The reduction on seizure burden was associated with a limited reduction on the generation of SBDPs but was correlated with a reduction in astrocytosis, microglia activation and cell sprouting. Together, these observations provide evidence for the role of calpain in epileptogenesis. In addition, provide proof-of-principle for the use of calpain inhibitors as a novel strategy to prevent epileptic seizures and its associated pathologies.

Study of the pedestal process for reducing sidewall scattering in photonic waveguides.

In this work we investigate the principles of an alternative method for defining sidewall in optical waveguides fabricated using planar technology. The efficiency of this method is demonstrated through simulations and experimental results regarding propagation losses of a solid core ARROW waveguide fabricated on silicon substrate. It is well known that waveguides fabricated using sidewalls etched via Reactive Ion Etching (RIE) can present high sidewall roughness, especially if metallic hard-masks are used. This is largely responsible for the undesirable losses observed in these waveguides. The basic strategy of the proposed method is to do the etching step, in the fabrication of the waveguides, before the deposition of the core, so as to have the lower cladding layer and part of the silicon substrate etched away. Only after this, is the core of the waveguide deposited. This results in a waveguide sustained by a silicon pedestal. With this process, losses as low as 0.45 dB cm-1 for multimode and 0.84 dB cm-1 for single mode waveguides are obtained. The numerical simulations demonstrate that roughness in sidewalls implicates in propagation losses which are at least five times larger that those in the bulk of the material, thus corroborating the idea behind the proposed method.

In vivo and in vitro degradation comparison of pure Mg, Mg-10Gd and Mg-2Ag: a short term study.

The purpose of this study was to compare short term in vitro and in vivo biodegradation studies with low purity Mg (> 99.94 %), Mg-10Gd and Mg-2Ag designed for biodegradable implant applications. Three in vitro testing conditions were applied, using (i) phosphate buffered saline (PBS), (ii) Hank's balanced salt solution (HBSS) and (iii) Dulbecco's modified eagle medium (DMEM) in 5 % CO2 under sterile conditions. Gas evolution and mass loss (ML) were assessed, as well as the degradation layer, by elemental mapping and scanning electron microscopy (SEM). In vivo, implantations were performed on male Sprague-Dawley rats evaluating both, gas cavity volume and implant volume reduction by micro-computed tomography (µCT), 7 d after implantation. Samples were produced by casting, solution heat treatment and extrusion in disc and pin shape for the in vitro and in vivo experiments, respectively. Results showed that when the processing of the Mg sample varied, differences were found not only in the alloy impurity content and the grain size, but also in the corrosion behaviour. An increase of Fe and Ni or a large grain size seemed to play a major role in the degradation process, while the influence of alloying elements, such as Gd and Ag, played a secondary role. Results also indicated that cell culture conditions induced degradation rates and degradation layer elemental composition comparable to in vivo conditions. These in vitro and in vivo degradation layers consisted of Mg hydroxide, Mg-Ca carbonate and Ca phosphate.

Identification of a Polyketide Synthase Involved in Sorbicillin Biosynthesis by Penicillium chrysogenum.

UNLABELLED: Secondary metabolism in Penicillium chrysogenum was intensively subjected to classical strain improvement (CSI), the resulting industrial strains producing high levels of ß-lactams. During this process, the production of yellow pigments, including sorbicillinoids, was eliminated as part of a strategy to enable the rapid purification of ß-lactams. Here we report the identification of the polyketide synthase (PKS) gene essential for sorbicillinoid biosynthesis in P. chrysogenum We demonstrate that the production of polyketide precursors like sorbicillinol and dihydrosorbicillinol as well as their derivatives bisorbicillinoids requires the function of a highly reducing PKS encoded by the gene Pc21g05080 (pks13). This gene belongs to the cluster that was mutated and transcriptionally silenced during the strain improvement program. Using an improved ß-lactam-producing strain, repair of the mutation in pks13 led to the restoration of sorbicillinoid production. This now enables genetic studies on the mechanism of sorbicillinoid biosynthesis in P. chrysogenum and opens new perspectives for pathway engineering. IMPORTANCE: Sorbicillinoids are secondary metabolites with antiviral, anti-inflammatory, and antimicrobial activities produced by filamentous fungi. This study identified the gene cluster responsible for sorbicillinoid formation in Penicillium chrysogenum, which now allows engineering of this diverse group of compounds.

Microscopic Origin of Heisenberg and Non-Heisenberg Exchange Interactions in Ferromagnetic bcc Fe.

By means of first principles calculations, we investigate the nature of exchange coupling in ferromagnetic bcc Fe on a microscopic level. Analyzing the basic electronic structure reveals a drastic difference between the 3d orbitals of E_{g} and T_{2g} symmetries. The latter ones define the shape of the Fermi surface, while the former ones form weakly interacting impurity levels. We demonstrate that, as a result of this, in Fe the T_{2g} orbitals participate in exchange interactions, which are only weakly dependent on the configuration of the spin moments and thus can be classified as Heisenberg-like. These couplings are shown to be driven by Fermi surface nesting. In contrast, for the E_{g} states, the Heisenberg picture breaks down since the corresponding contribution to the exchange interactions is shown to strongly depend on the reference state they are extracted from. Our analysis of the nearest-neighbor coupling indicates that the interactions among E_{g} states are mainly proportional to the corresponding hopping integral and thus can be attributed to be of double-exchange origin. By making a comparison to other magnetic transition metals, we put the results of bcc Fe into context and argue that iron has a unique behavior when it comes to magnetic exchange interactions.

Blood pressure-lowering efficacy of reserpine for primary hypertension.

BACKGROUND: Many antihypertensive agents exist today for the treatment of primary hypertension (systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg, or both). Randomised controlled trials (RCTs) have been carried out to investigate the evidence for these agents. There is, for example, strong RCT evidence that thiazides reduce mortality and morbidity. Some of those trials used reserpine as a second-line therapy. However, the dose-related blood pressure reduction with this agent is not known. OBJECTIVES: The primary objective of this review was to quantify the dose-related efficacy of reserpine versus placebo or no treatment in reducing systolic blood pressure (SBP) or diastolic blood pressure (DBP), or both.We also aimed to evaluate the dose-related effects of reserpine on mean arterial blood pressure (MAP) and heart rate (HR), as well as the dose-related effects on withdrawals due to adverse events. SEARCH METHODS: We searched the Cochrane Hypertension Group Specialised Register (January 1946 to October 2016), CENTRAL (2016, Issue 10), MEDLINE (January 1946 to October 2016), Embase (January 1974 to October 2016), and ClinicalTrials.gov (all dates to October 2016). We also traced citations in the reference sections of the retrieved studies. SELECTION CRITERIA: Included studies were truly randomised controlled trials (RCTs) comparing reserpine monotherapy to placebo or no treatment in participants with primary hypertension. DATA COLLECTION AND ANALYSIS: We assessed methods of randomisation and concealment. We extracted and analysed data on blood pressure reduction, heart rate, and withdrawal due to adverse effects. MAIN RESULTS: We found four RCTs (with a total of 237 participants) that met the inclusion criteria, none of which we found through the 2016 update search. The overall pooled effect demonstrates a statistically significant systolic blood pressure (SBP) reduction in participants taking reserpine compared with placebo (weighted mean difference (WMD) -7.92, 95% confidence interval (CI) -14.05 to -1.78). Because of significant heterogeneity across the trials, a significant effect in diastolic blood pressure (DBP), mean arterial pressure (MAP), and heart rate (HR) could not be found. A dose of reserpine 0.5 mg/day or greater achieved the SBP effects. However, we could not determine the dose-response pattern because of the small number of trials. We did not combine data from the trial that investigated Rauwiloid against placebo with reserpine data from the remaining three trials. This is because Rauwiloid is a different alkaloid extract of the plant Rauwolfia serpentina, and the dose used is not comparable to reserpine. None of the included trials reported withdrawals due to adverse effects. AUTHORS' CONCLUSIONS: Reserpine is effective in reducing SBP roughly to the same degree as other first-line antihypertensive drugs. However, we could not make definite conclusions regarding the dose-response pattern because of the small number of included trials. More RCTs are needed to assess the effects of reserpine on blood pressure and to determine the dose-related safety profile before the role of this drug in the treatment of primary hypertension can be established.