First report of Fusarium falciforme causing root rot and wilt on strawberry in Sinaloa, Mexico.

In Mexico strawberry production has great economic importance for the local and export markets as the country is the main strawberry supplier to the United States (SIAP, 2020). In 2022, strawberry plants with yellowing and wilting leaves, root rot and wilting, necrosis of vascular bundles and small fruits symptoms were observed in different commercial fields in the north-central Mexican state of Sinaloa, causing yield losses of about 10%. Typical Fusarium spp. colonies were recovered from all samples. They produced abundant white aerial mycelium with cream to orange pigment and branched septate hyphae (Fig. 1) (Leslie and Summerell, 2006). A total of 18 monosporic isolates were obtained by serial dilutions. The 18 isolates grown for 10 days on carnation leaf agar (CLA) produced hyaline microconidia with 0-2 septa, measuring 9.2 - 15.4 by 4.5 - 6.5 µm (n = 40) and hyaline macroconidia with three septa that measured 28.4 - 53.5 by 4.5 - 9 µm (n = 40). Chlamydospores were not observed. A fragment of the translation elongation factor 1-alpha (EF1-alpha) gene was amplified by polymerase chain reaction (PCR) using the primer pair EF-1/EF-2 (O'Donnell et al. 1998) from two monosporic isolates. The sequences were registered in the NCBI GenBank under accession numbers OR878541 and OR878543 (FRESIN178 and FRESIN194). BLASTn queries of NCBI GenBank identified the sequences as F. falciforme with 98% and 100% similarity to accession numbers OQ262968 and DQ246941 respectively. Fusarium ID database also identified the sequences as F. falciforme, is a member of the F. solani species complex (FSSC). Phylogenetic analysis revealed the partial EF1 sequences grouped with F. falciforme (Fig. 2). A pathogenicity test was performed on thirty strawberry plants (cv. Cabrillo) grown in sterile vermiculite. The plants were inoculated by immersing roots in 20 mL of a conidial suspension (1 × 105 conidia/mL) of isolate FRESIN194. Twelve uninoculated plants served as the control. All plants were grown for 60 days under greenhouse conditions (28 to 35°C). The assay was repeated twice. After 50 days, symptoms of root rot and wilting leaves like those observed in the field were observed. Uninoculated control plants did not develop symptoms. The fungus was reisolated from necrotic tissues of the inoculated plants and identified as F. falciforme by sequencing the EF1-alpha gene and morphological characteristics, completing Koch's postulates. Fusarium falciforme has been reported as the causal agent of root rot, stem rot, and wilt of tomato, papaya, chickpea, onion, common bean, and maize in Mexico (Díaz-Najera et al. 2021, Douriet-Angulo et al. 2021, Felix et al 2022, Tirado-Ramírez et al 2018, Vega-Gutiérrez et al. 2019a, Vega-Gutiérrez et al. 2019b). To our knowledge this is the first report of F. falciforme causing root rot and wilt on strawberry in Sinaloa, Mexico. This result provides useful information for the development and implementation of disease control strategies to mitigate damage caused by F. falciforme.

Urease-powered nanobots for radionuclide bladder cancer therapy.

Bladder cancer treatment via intravesical drug administration achieves reasonable survival rates but suffers from low therapeutic efficacy. To address the latter, self-propelled nanoparticles or nanobots have been proposed, taking advantage of their enhanced diffusion and mixing capabilities in urine when compared with conventional drugs or passive nanoparticles. However, the translational capabilities of nanobots in treating bladder cancer are underexplored. Here, we tested radiolabelled mesoporous silica-based urease-powered nanobots in an orthotopic mouse model of bladder cancer. In vivo and ex vivo results demonstrated enhanced nanobot accumulation at the tumour site, with an eightfold increase revealed by positron emission tomography in vivo. Label-free optical contrast based on polarization-dependent scattered light-sheet microscopy of cleared bladders confirmed tumour penetration by nanobots ex vivo. Treating tumour-bearing mice with intravesically administered radio-iodinated nanobots for radionuclide therapy resulted in a tumour size reduction of about 90%, positioning nanobots as efficient delivery nanosystems for bladder cancer therapy.

A review of the management of water resources in Malaysia facing climate change.

This paper reviewed the impacts of climate change on the management of the water sector in Malaysia discussing the current status of water resources, water service, and water-related disasters. The implementation of engineering practices was discussed to provide the detailed assessment of climate change impacts, risks, and adaptation for sustainable development. The narrative methods of reviewing the literatures were used to get an understanding on the engineering practices of water infrastructures, implication of the government policies, and several models as the main motivation behind the concept of integrated water resource management to contribute as part of the sustainable development goals to achieve a better and more sustainable future for all. The findings of this review highlighted the impacts of climate change on the rivers, sea, lakes, dams, and groundwater affecting the availability of water for domestic and industrial water supplies, irrigation, hydropower, and fisheries. The impacts of climate change on the water-related disasters have been indicated affecting drought-flood abrupt alternation and water pollution. Challenges of water management practices facing climate change should be aware of the updated intensity-duration-frequency curves, alternative sources of water, effective water demand management, efficiency of irrigation water, inter-basin water transfer, and nonrevenue water. The transferability of this review findings contribute to an engagement with the society and policy makers to mobilize for climate change adaptation in the water sector.

Multimodal imaging of the role of hyperglycemia following experimental subarachnoid hemorrhage.

Hyperglycemia has been linked to worsening outcomes after subarachnoid hemorrhage (SAH). Nevertheless, the mechanisms involved in the pathogenesis of SAH have been scarcely evaluated so far. The role of hyperglycemia was assessed in an experimental model of SAH by T2 weighted, dynamic contrast-enhanced magnetic resonance imaging (T2W and DCE-MRI), [18F]BR-351 PET imaging and immunohistochemistry. Measures included the volume of bleeding, the extent of cerebral infarction and brain edema, blood brain barrier disruption (BBBd), neutrophil infiltration and matrix metalloprotease (MMP) activation. The neurofunctional outcome, neurodegeneration and myelinization were also investigated. The induction of hyperglycemia increased mortality, the size of the ischemic lesion, brain edema, neurodegeneration and worsened neurological outcome during the first 3 days after SAH in rats. In addition, these results show for the first time the exacerbating effect of hyperglycemia on in vivo MMP activation, Intercellular Adhesion Molecule 1 (ICAM-1) expression and neutrophil infiltration together with increased BBBd, bleeding volume and fibrinogen accumulation at days 1 and 3 after SAH. Notably, these data provide valuable insight into the detrimental effect of hyperglycemia on early BBB damage mediated by neutrophil infiltration and MMP activation that could explain the worse prognosis in SAH.

First report of Fusarium verticillioides causing safflower root rot in Sinaloa, Mexico.

Safflower cultivation is of great socioeconomic importance worldwide. Production is intended for the extraction of oil from the seeds. In 2021 Mexico ranked fifth in world production with approximately 52,553.28 tons (SIAP, 2021). In April 2022, in the north-central zone of Sinaloa, Mexico, diseased plants were reported in fields planted with safflower. Symptoms included chlorotic plants, necrosis and rot in vascular bundles, dwarfed plants and reflexed plants bent towards the ground. The disease caused estimated losses of 15% of seed production, with respect to the production obtained from the previous year in the safflower fields surveyed. Twenty-five plants with symptoms were sampled to isolate the pathogen. Plants were cut at the base of the stem near the roots and roots cut into 5 mm2 pieces. Tissue samples were superficially disinfected by immersing in 70% alcohol for 10 sec, 2% sodium hypochlorite for 1 min, washed in sterile water, and placed on potato dextrose agar (PDA) at 28 ºC for 7 days in the dark. Twelve monosporic isolates derived from the PDA culture were morphologically characterized. Abundant white aerial mycelium and small pink to dark violet pigments in the center of the culture were observed. From 10-day-old cultures grown on carnation leaf agar medium microconidia and macroconidia were produced. Microconidia were hyaline, had zero to two septa, and were oval or ellipsoidal, 4.6 to 14 x 1.8 to 4.2 µm (n = 40). The macroconidia were hyaline, were slightly curved with three to five septa, and measured from 26 to 69 x 3 to 6.1 µm (n = 40). No chlamydospores were observed. According to the morphological characteristics, the isolates were identified as Fusarium verticillioides (Leslie and Summerell, 2006). DNA was extracted from one isolate and the Translation Elongation Factor 1-α (EF1) gene was amplified and sequenced (O'Donnell et al. 2010). The sequence obtained from isolate FV3CARCULSIN with 645 base pairs was submitted to NCBI GenBank with accession number OQ262963. The BLAST search revealed 100% similarity with F. verticillioides isolate 13 (KM598773) (Lizárraga et al. 2015). Identification in FUSARIUM ID resulted in a 99.85% similarity with isolate F. verticillioides CBS 131389 (MN534047) (Yilmaz et al. 2021). A phylogenetic tree, made with sequences of the EF1 gene, revealed that FV3CARCULSIN was most closely related to F. verticillioides (100% bootstrap). Pathogenicity tests were carried out on safflower plants (cv. Oleico) grown in sterile vermiculite. Plants were inoculated with a conidial suspension (1 × 105 conidia/ml) obtained from FV3CARCULSIN grown on PDA for 7 days. A total of 45 plants were inoculated by drenching the roots with 20 ml of inoculum when the plants were 20 days old. Fifteen plants served as negative controls without inoculation. Plants were kept for 60 days in greenhouse conditions; however, after 45 days the plants began to die. The assay was conducted twice. Rotting and necrosis was observed in the roots of the plants. The pathogen was reisolated from the tissue of all the plants with symptoms and identified as F. verticillioides using morphological characteristics and EF1 sequences, completing Koch's postulates. No symptoms were observed in control plants after 60 days. This is the first report of root rot in safflower caused by F. verticillioides in Mexico. The fungus has been reported in maize (Figueroa et al. 2010), but it is unknown if it could be the same pathogen of safflower. Identification of the pathogen is important for implementing management methods to reduce yield losses and for additional studies on the impact of the disease on oil quality extracted from safflower seeds.

Fusarium verticillioides Causing Root and Stem Rot in Papaya (Carica papaya) in Mexico.

Mexico is the fifth largest producer of papaya in the world with an estimated production of 1, 134, 753 metric tons per year (FAOSTAT 2022). In February 2022, in the center zone of Sinaloa State (Mexico), in a seedling-producing greenhouse, papaya seedlings were observed with an incidence (20%) of root and stem rot and necrotic tissue. Symptomatic tissues were collected from 10 papaya plants, which were cut into small pieces and surface sterilized sequentially with 70% alcohol for 20 s and 1% sodium hypochlorite for 2 min, dried, placed on potato dextrose agar (PDA), and incubated at 26°C in darkness for 5 days. Typical Fusarium spp. colonies were obtained from all root samples. Ten pure cultures were obtained by single-spore culturing and morphologically characterized on PDA and carnation leaf agar (CLA) media. On PDA, the colonies produced abundant white aerial mycelium, and the center of old cultures was yellow pigmentation (Leslie and Summerell 2006). From 10-day-old cultures grown on CLA medium, macroconidia were slightly curved, which showed zero to three septa, with some slightly sharp apices, and basal cells with notches, the measurements were from 22.53 to 48.94 x 6.9 to 13.73 µm (n= 50). The microconidia were presented in abundant chains of microconidia. The microconidia presented thin walls, oval and hyaline in shape, forming long chains, measuring 10.4 to 14.25 x 2.4 to 6.8 µm (n= 50). Chlamydospores were not observed. The translation elongation factor 1 alpha (EF1-α) gene (O'Donnell et al. 1998) was amplified by polymerase chain reaction and sequenced from isolate FVTPPYCULSIN (GenBank accession no. OM966892). Maximum likelihood analysis was carried out using the EF1-α sequence (OM966892) and other species from the genus Fusarium. Phylogenetic analysis revealed that the isolate was Fusarium verticillioides (100% bootstrap). Furthermore, the isolate FVTPPYCULSIN was 100 % similar with other reported Fusarium verticillioides sequence (GenBank accession nos. MN657268) (Dharanendra et al. 2019). Pathogenicity tests were performed on 60-day-old papaya plants (cultivar Maradol) grown on autoclaved sandy loam soil mix. Ten plants per isolate (n = 10) were inoculated by drenching with 20 ml of a conidial suspension (1 × 105 CFU/ml) of each isolate per plant. The suspension was obtained by collecting the spores of each isolate grown on PDA with 10 ml of an isotonic saline solution. Ten noninoculated plants served as controls. Plants were maintained for 60 days under greenhouse conditions (25 to 30°C). The assay was conducted twice. Root and stem rot similar to that observed on the infected plants in the greenhouse was observed on the papaya plants. No symptoms were observed on noninoculated control plants after 60 days. The pathogen was reisolated from the necrotic tissue from all inoculated plants and was identified again as Fusarium verticillioides by sequencing the partial EF1-α gene again and based on its morphological characteristics, genetic analysis, and pathogenicity test, fulfilling Koch's postulates. The molecular identification was confirmed via BLAST on the Fusarium ID and Fusarium MLST databases. The isolate FVTPPYCULSIN was deposited in the fungal collection of the Faculty of Agronomy of the Autonomous University of Sinaloa. To our knowledge, this is the first report of root and stem rot of papaya caused by F. verticillioides. Papaya is an important fruit crop in Mexico, and the occurrence of this disease needs to be taken into account in papaya production.

First report of Fusarium keratoplasticum causing strawberry root rot in Sinaloa, Mexico.

Strawberry (Fragaria × ananassa) is a fruit of economic importance for Mexico, occupying the third place in world production, with an approximate production of 861, 337 t (SIAP, 2021). In January 2021, in Culiacan, Sinaloa, Mexico (24°46'46″N; 107°27'04″ W), wilting symptoms (stunted growth, leaf yellowing and wilting, necrosis in vascular bundles, root rot and wilting) were observed on commercial strawberry crops, with an incidence of 5 to 10 %. Tissue samples from symptomatic roots were cut and disinfected with alcohol, sodium hypochlorite and sterile water, to later be plated on potato dextrose agar (PDA). Fifteen monosporic isolates were obtained by single-spore culturing (Hansen and Smith, 1932). Typical Fusarium spp. colonies were obtained from all root samples. On PDA the colonies were abundant with white aerial mycelium, hyphae were branched and septate, and light-yellow pigmentation was observed in the center of old cultures (Leslie and Summerell 2006). From 10-day-old cultures grown on carnation leaf agar medium, macroconidia were slightly curved, showing three marked septa, broad central cells, slightly tapered apices, foot-shaped basal cells and measured 59.6 - 73.4 (x̄ = 68.7) x 10.4 - 14.9 µm (x̄ = 13.6) (n = 40). The microconidia (n = 40) were thin-walled, hyaline, ovoid unicellular that measured 19.7 - 32.2 (x̄ = 26.6) x 8.8 - 11.8 µm (x̄ = 10.2). The translation elongation factor 1 alpha (EF1-α) gene (O'Donnell et al. 1998) was amplified by polymerase chain reaction and sequenced. Maximum likelihood analysis was carried out using the EF1-α sequence from the isolate FKTFRESCULSIN (GenBank accession no. OK491929) and other Neocosmospora and Fusarium species. Phylogenetic analysis revealed the isolate was Fusarium keratoplasticum (currently named Neocosmospora keratoplastica) belonging to the Fusarium solani species complex (FSSC). Pathogenicity tests were performed on strawberry plants (cultivar Camarosa) grown on autoclaved sandy loam soil mix. Twenty plants were inoculated by drenching with 20 ml of a conidial suspension (1 × 105 CFU/ml) in an isotonic saline solution of FKTFRESCULSIN grown on PDA. Ten uninoculated plants served as controls. Plants were maintained for 60 days under greenhouse conditions (25 to 30°C). The assay was conducted twice. Root and stem rot similar to that observed on the infected plants in the field was observed. No symptoms were observed on uninoculated control plants after 60 days. The pathogen was reisolated from necrotic tissue from all inoculated plants and identified as F. keratoplasticum by sequencing the partial EF1-α gene and based on its morphological characteristics, thus fulfilling Koch's postulates. To our knowledge, this is the first report of root rot and wilt of strawberry caused by F. keratoplasticum in Mexico; it also contributes knowledge to the scientific community, since there is little information about this pathogen causing damage to plants in the world. Strawberry is an important crop in Mexico, and the occurrence of this disease could threaten strawberry production.

Therapeutic effect of α7 nicotinic receptor activation after ischemic stroke in rats.

Nicotinic acetylcholine α7 receptors (α7 nAChRs) have a well-known modulator effect in neuroinflammation. Yet, the therapeutical effect of α7 nAChRs activation after stroke has been scarcely evaluated to date. The role of α7 nAChRs activation with PHA 568487 on inflammation after brain ischemia was assessed with positron emission tomography (PET) using [18F]DPA-714 and [18F]BR-351 radiotracers after transient middle cerebral artery occlusion (MCAO) in rats. The assessment of brain oedema, blood brain barrier (BBB) disruption and neurofunctional progression after treatment was evaluated with T2 weighted and dynamic contrast-enhanced magnetic resonance imaging (T2 W and DCE-MRI) and neurological evaluation. The activation of α7 nAChRs resulted in a decrease of ischemic lesion, midline displacement and cell neurodegeneration from days 3 to 7 after ischemia. Besides, the treatment with PHA 568487 improved the neurofunctional outcome. Treated ischemic rats showed a significant [18F]DPA-714-PET uptake reduction at day 7 together with a decrease of activated microglia/infiltrated macrophages. Likewise, the activation of α7 receptors displayed an increase of [18F]BR-351-PET signal in ischemic cortical regions, which resulted from the overactivation of MMP-2. Finally, the treatment with PHA 568487 showed a protective effect on BBB disruption and blood brain vessel integrity after cerebral ischemia.

Pharmacokinetic Evaluation of New Drugs Using a Multi-Labelling Approach and PET Imaging: Application to a Drug Candidate with Potential Application in Neuromuscular Disorders.

BACKGROUND AND OBJECTIVE: The determination of pharmacokinetic properties of new chemical entities is a key step in the process of drug development. Positron emission tomography (PET) is an ideal technique to obtain both biodistribution and pharmacokinetic parameters of new compounds over a wide range of chemical modalities. Here, we use a multi-radionuclide/multi-position labelling approach to investigate distribution, elimination, and metabolism of a triazole-based FKBP12 ligand (AHK2) with potential application in neuromuscular disorders. METHODS: Target engagement and stabilizing capacity of the drug candidate (AHK2) towards FKBP12-RyR was evaluated using competitive ligand binding and proximity ligation assays, respectively. Subsequently, AHK2 was labelled either with the positron emitter carbon-11 (11C) via 11C-methylation to yield both [11C]AHK2.1 and [11C]AHK2.2, or by palladium-catalysed reduction of the corresponding 5-iodotriazole derivative using 3H gas to yield [3H]AHK2. Metabolism was first investigated in vitro using liver microsomes. PET imaging studies in rats after intravenous (IV) administration at different doses (1 µg/Kg and 5 mg/Kg) were combined with determination of arterial blood time-activity curves (TACs) and analysis of plasma samples by high performance liquid chromatography (HPLC) to quantify radioactive metabolites. Arterial TACs were obtained in continuous mode by using an in-house developed system that enables extracorporeal blood circulation and continuous measurement of radioactivity in the blood. Pharmacokinetic parameters were determined by non-compartmental modelling of the TACs. RESULTS: In vitro studies indicate that AHK2 binds to FKBP12 at the rapamycin-binding pocket, presenting activity as a FKBP12/RyR stabilizer. [11C]AHK2.1, [11C]AHK2.2 and [3H]AHK2 could be obtained in overall non-decay corrected radiochemical yields of 14 ± 2%, 15 ± 2% and 0.05%, respectively. Molar activities were 60-110 GBq/µmol, 68-122 GBq/µmol and 0.4-0.5 GBq/µmol, respectively. In vitro results showed that oxidation of the thioether group into sulfoxide, demethylation of the CH3O-Ar residue and demethylation of -N(CH3)2 were the main metabolic pathways. Fast metabolism was observed in vivo. Pharmacokinetic parameters obtained from metabolite-corrected arterial blood TACs showed a short half-life (12.6 ± 3.3 min). Dynamic PET imaging showed elimination via urine when [11C]AHK2.2 was administered, probably reflecting the biodistribution of [11C]methanol as the major metabolite. Contrarily, accumulation in the gastrointestinal track was observed after administration of [11C]AKH2.1. CONCLUSIONS: AHK2 binds to FKBP12 at the rapamycin-binding pocket, presenting activity as a FKBP12/RyR stabilizer. Studies performed with the 3H- and 11C-labelled FKBP12/RyR stabilizer AHK2 confirm fast blood clearance, linear pharmacokinetics and rapid metabolism involving oxidation of the sulfide and amine moieties and oxidative demethylation of the CH3-O-Ar and tertiary amine groups as the main pathways. PET studies suggest that knowledge about metabolic pathways is paramount to interpret images.

Assessment of Regional Lung Ventilation with Positron Emission Tomography Using the Radiofluorinated Gas [18F]SF6: Application to an Animal Model of Impaired Ventilation.

PURPOSE: Clinical ventilation studies are primarily performed with computerized tomography (CT) and more often with single-photon emission Computerized tomography (SPECT) using radiolabelled aerosols, both presenting certain limitations. Here, we investigate the use of the radiofluorinated gas [18F]SF6 as a positron emission tomography (PET) ventilation marker in an animal model of impaired lung ventilation. PROCEDURES: Sprague-Dawley rats (n = 15) were randomly assigned to spontaneous ventilation (sham group), endotracheal administration of phosphate-buffered saline (PBS group), or endotracheal administration of lipopolysaccharide (LPS group). PET-[18F]SF6 images (10-min acquisition) were acquired at t = 48 h after LPS or PBS administration under mechanical ventilation. CT images were acquired after each PET session. Volumes of interest were manually delineated in the lungs on CT images, and voxel-by-voxel analysis was carried out on PET images to obtain the corresponding histograms. After the imaging sessions, lungs were harvested to conduct histological analysis. RESULTS: Ventilation studies in sham animals showed uniform distribution of [18F]SF6 and fast elimination of the radioactivity after discontinuation of the administration. For PBS- and LPS-treated rats, ventilation defects were observed on PET images in some animals, identified as regions with low presence of the radiolabelled gas. Hypoventilated areas co-localized with regions with higher x-ray attenuation than healthy lungs on the CT images, suggesting the presence of oedema and, in some cases, atelectasis. Histograms obtained from PET images showed quasi-Gaussian distributions for control animals, while PBS- and LPS-treated animals demonstrated the presence of hypoventilated voxels. Deviation of the histograms from Gaussian distribution correlated with histological score was obtained by ex vivo histological analysis. CONCLUSIONS: [18F]SF6 is an appropriate marker of regional lung ventilation and may find application in the early diagnose of acute lung disease.

Longitudinal evaluation of neuroinflammation and oxidative stress in a mouse model of Alzheimer disease using positron emission tomography.

BACKGROUND: Validation of new biomarkers of Alzheimer disease (AD) is crucial for the successful development and implementation of treatment strategies. Additional to traditional AT(N) biomarkers, neuroinflammation biomarkers, such as translocator protein (TSPO) and cystine/glutamine antiporter system (xc-), could be considered when assessing AD progression. Herein, we report the longitudinal investigation of [18F]DPA-714 and [18F]FSPG for their ability to detect TSPO and xc- biomarkers, respectively, in the 5xFAD mouse model for AD. METHODS: Expression of TSPO and xc- system was assessed longitudinally (2-12 months of age) on 5xFAD mice and their respective controls by positron emission tomography (PET) imaging using radioligands [18F]DPA-714 and [18F]FSPG. In parallel, in the same mice, amyloid-ß plaque deposition was assessed with the amyloid PET radiotracer [18F]florbetaben. In vivo findings were correlated to ex vivo immunofluorescence staining of TSPO and xc- in microglia/macrophages and astrocytes on brain slices. Physiological changes of the brain tissue were assessed by magnetic resonance imaging (MRI) in 12-month-old mice. RESULTS: PET studies showed a significant increase in the uptake of [18F]DPA-714 and [18F]FSPG in the cortex, hippocampus, and thalamus in 5xFAD but not in WT mice over time. The results correlate with Aß plaque deposition. Ex vivo staining confirmed higher TSPO overexpression in both, microglia/macrophages and astrocytes, and overexpression of xc- in non-glial cells of 5xFAD mice. Additionally, the results show that Aß plaques were surrounded by microglia/macrophages overexpressing TSPO. MRI studies showed significant tissue shrinkage and microstructural alterations in 5xFAD mice compared to controls. CONCLUSIONS: TSPO and xc- overexpression can be assessed by [18F]DPA-714 and [18F]FSPG, respectively, and correlate with the level of Aß plaque deposition obtained with a PET amyloid tracer. These results position the two tracers as promising imaging tools for the evaluation of disease progression. Longitudinal in vivo study in the 5xFAD mouse model shows that TSPO and oxidative stress assessment through [18F]DPA-714 and [18F]FSPG-PET imaging, respectively, could serve as a potential tool for the evaluation of Alzheimer disease progression.

First Report of Mango malformation disease caused by Fusarium proliferatum in Mexico.

Mango (Mangifera indica L.) is the most economically important fruit in the tropical and subtropical regions of the world. Mexico is ranked the fourth largest mango producer worldwide with an approximate production of 2 396 675 t in 2019 (FAO 2020). Sinaloa is the principal mango production state in Mexico with 410,147 t in 2020 (SIAP 2021). Mango malformation disease (MMD) is one of the main limitations in the production of this crop worldwide, causing serious losses in yield. During December 2017 to April 2018, symptoms of MMD were observed in commercial mango in the municipality of El Rosario (Sinaloa, Mexico). These symptoms included malformed and compacted inflorescences, abnormal development of vegetative shoots with shortened internodes at an incidence of 25 %. Tissue from 15 symptomatic trees were superficially disinfested with 2% sodium hypochlorite and transferred to potato dextrose agar (PDA). Typical Fusarium spp. colonies were obtained from all samples. Fifteen pure cultures were obtained by single spore culturing. White to cream-colored aerial mycelia of typical Fusarium colonies were observed from all samples on PDA (Leslie and Summerell 2006). From 10-day-old cultures grown on carnation leaf agar medium, macroconidia (n = 50) were hyaline, relatively slender with a curve, 4 to 5 septate, and measured 39.5 to 76.8 x 5.7 to 9.5 µm. The microconidia (n = 50) were hyaline and pyriform, without septa, and measured 8.1 to 10.6 x 5.1 to 6.9 µm. Chlamydospores were observed. The EF1-α gene (O'Donnell et al. 1998) was amplified by PCR and sequenced from the isolates. The EF1-α sequence from one representative isolate (128FRSIN) was deposited in GenBank with the accession number MK932806. Maximum likelihood analysis was carried out using the representative EF1-α sequence for F. proliferatum (MK932806) and other Fusarium species. Phylogenetic analysis revealed the isolate most closely related was F. proliferatum (100% bootstrap). The molecular identification was also confirmed via BLAST on the Fusarium ID and Fusarium MLST databases. The pathogenicity tests were carried out on healthy three-month-old mango plants. Twenty plants and five shoots per plant were inoculated with 20 µl of the conidial suspension (1 x 106 conidia/ml) (Freeman et al. 1999). Twenty plants served as noninoculated controls. Plants were maintained for 365 days under greenhouse conditions (25 to 30°C). The assay was conducted twice. Symptoms of multiple vegetative shoots and shortened internodes were observed four months after inoculation on the infected plants with an average disease of 4.5 in the first trial and 4.4 in the second assay according to the disease severity scale outlined by Iqbal et al., (2006). No symptoms were observed on non inoculated control plants after 365 days. One isolate per plant was isolated again from the plants with malformation symptoms (n=20), and identified again as F. proliferatum, by morphological and molecular characteristics. F. proliferatum was identified as the causal agent of MMD in China by Zhan et al. (2010). To our knowledge, this is the first report of F. proliferatum causing MMD in Mexico. The development of management strategies to prevent crop loss is required in this important mango production area.

Root Rot and Wilt caused by Fusarium nygamai of Bean (Phaseolus vulgaris) in Sinaloa, Mexico.

Bean (Phaseolus vulgaris) is the second most important crop in Mexico after corn due to high consumption in all regions of the country. Sinaloa state is ranked second in Mexico, producing 140,830 tons in 2020 (SIAP, 2021). In October 2020, wilting symptoms (stunted growth, withered leaves, root rot and wilt) were observed on commercial bean crops in three fields in Culiacan, Sinaloa with an incidence of 3 to 5%. Tissue samples from symptomatic roots were plated on potato dextrose agar (PDA). Typical Fusarium spp. colonies were obtained from all root samples. Three pure cultures were obtained by single-spore culturing. On PDA, the colonies produced abundant white aerial mycelium, and the center of old cultures was light pink with yellow pigmentation (Leslie and Summerell 2006). Macroconidia, from 10-day-old cultures grown on carnation leaf agar, were slightly curved, with three septa, wide central cells, slightly sharp apices, basal foot-shaped cells, measuring 38.5  2.5 × 5.5  1.0 µm (n = 40). Microconidia were hyaline, ovoid, unicellular and measured 12.0  1.5 x 4.8  0.95 µm (n= 40). Chlamydospores were not observed. The translation elongation factor 1 alpha (EF1-α) gene (O'Donnell et al. 1998) was amplified by polymerase chain reaction and sequenced from isolate FNTL6P7CULSIN (GenBank accession no. OK491917). Maximum likelihood analysis was carried out using the EF1-α sequence (OK491917) and other species from the genus Fusarium. Phylogenetic analysis revealed the isolate was F. nygamai (100% bootstrap). Moreover, isolate FNTL6P7CULSIN was 99.7% (648 bp/649bp), and 99.9 % (648bp/650bp) similar, respectively, with other reported F. nygamai sequences (GenBank accession no. OL415419 and KR612341). Pathogenicity tests were performed on 20-day-old bean plants (cultivar Mayocoba) grown on autoclaved sandy loam soil mix. Twenty plants were inoculated by drenching with 20 ml of a conidial suspension (1 × 105 CFU/ml) in an isotonic saline solution of FNTL6P7CULSIN grown on PDA. Ten uninoculated plants served as controls. Plants were maintained for 60 days under greenhouse conditions (25 to 30°C). The assay was conducted twice. Root and stem rot similar to that observed on the infected plants in the field was observed. No symptoms were observed on uninoculated control plants after 60 days. The pathogen was reisolated from necrotic tissue from all inoculated plants and identified as F. nygamai by sequencing the partial EF1-α gene and based on its morphological characteristics, thus fulfilling Koch's postulates. Fusarium nygamai was associated with Fusarium foot rot of rice in Sardinia by Balmas et al., (2000). Also, this pathogen was reported by Leyva (2015) causing root rot in Maize in Sinaloa, Mexico. To our knowledge, this is the first report of root rot and wilt of bean caused by F. nygamai in Mexico. Bean is an important crop in Mexico, and the occurrence of this disease could threaten bean production.

Endovascular administration of magnetized nanocarriers targeting brain delivery after stroke.

The increasing use of mechanical thrombectomy in stroke management has opened the window to local intraarterial brain delivery of therapeutic agents. In this context, the use of nanomedicine could further improve the delivery of new treatments for specific brain targeting, tracking and guidance. In this study we take advantage of this new endovascular approach to deliver biocompatible poly(D-L-lactic-co-glycolic acid) (PLGA) nanocapsules functionalized with superparamagnetic iron oxide nanoparticles and Cy7.5 for magnetic targeting, magnetic resonance and fluorescent molecular imaging. A complete biodistribution study in naïve (n = 59) and ischemic (n = 51) mice receiving intravenous or intraarterial nanocapsules, with two different magnet devices and imaged from 30 min to 48 h, showed an extraordinary advantage of the intraarterial route for brain delivery with a specific improvement in cortical targeting when using a magnetic device in both control and ischemic conditions. Safety was evaluated in ischemic mice (n = 69) showing no signs of systemic toxicity nor increasing mortality, infarct lesions or hemorrhages. In conclusion, the challenging brain delivery of therapeutic nanomaterials could be efficiently and safely overcome with a controlled endovascular administration and magnetic targeting, which could be considered in the context of endovascular interventions for the delivery of multiple treatments for stroke.

Opposite alterations of 5-HT2A receptor brain density in subjects with schizophrenia: relevance of radiotracers pharmacological profile.

The status of serotonin 5-HT2A receptors (5-HT2ARs) in schizophrenia has been controversial. In vivo positron emission tomography neuroimaging and in vitro post-mortem binding studies have reported conflicting results about 5-HT2AR density. Radiotracers bind different receptor conformations depending on their agonist, antagonist or inverse agonist properties. This study investigates 5-HT2AR density in the post-mortem prefrontal cortex from subjects with schizophrenia and controls using three radiotracers with a different pharmacological profile. The specific binding parameters of the inverse agonist [18F]altanserin, the agonist [3H]lysergic acid diethylamide (LSD) and the antagonist [3H]MDL100907 to brain cortex membranes from 20 subjects with schizophrenia and 20 individually matched controls were evaluated under similar methodological conditions. Ten schizophrenia subjects were antipsychotic-free at death. Saturation curve analyses were performed by non-linear regression to obtain a maximal density of binding sites (Bmax) and the affinity of the respective radiotracers (Kd). In schizophrenia subjects, 5-HT2AR density was decreased when quantified by [18F]altanserin binding, whereas increased when evaluated by [3H]LSD binding. However, [3H]MDL100907 binding was unaltered. A slight loss of affinity (higher Kd) was observed exclusively in [3H]LSD binding. The findings were more evident in antipsychotic-free subjects than in antipsychotic-treated subjects. In conclusion, a higher proportion of the 5-HT2AR-active functional conformation, which is rather identified by agonist radiotracers, was observed in schizophrenia patients. A consequent reduction of the inactive 5-HT2AR conformation, which is preferentially identified by inverse agonist radiotracers, was also obtained. Antagonist radiotracers do not distinguish between molecular conformations of the receptor, and accordingly, the absence of changes was shown. These results are compatible with the proposed increased functional activity of brain cortical 5-HT2ARs in schizophrenia.

Longitudinal evaluation of a novel BChE PET tracer as an early in vivo biomarker in the brain of a mouse model for Alzheimer disease.

Purpose: The increase in butyrylcholinesterase (BChE) activity in the brain of Alzheimer disease (AD) patients and animal models of AD position this enzyme as a potential biomarker of the disease. However, the information on the ability of BChE to serve as AD biomarker is contradicting, also due to scarce longitudinal studies of BChE activity abundance. Here, we report 11C-labeling, in vivo stability, biodistribution, and longitudinal study on BChE abundance in the brains of control and 5xFAD (AD model) animals, using a potent BChE selective inhibitor, [11C]4, and positron emission tomography (PET) in combination with computerised tomography (CT). We correlate the results with in vivo amyloid beta (Aß) deposition, longitudinally assessed by [18F]florbetaben-PET imaging. Methods: [11C]4 was radiolabelled through 11C-methylation. Metabolism studies were performed on blood and brain samples of female wild type (WT) mice. Biodistribution studies were performed in female WT mice using dynamic PET-CT imaging. Specific binding was demonstrated by ex vivo and in vivo PET imaging blocking studies in female WT and 5xFAD mice at the age of 7 months. Longitudinal PET imaging of BChE was conducted in female 5xFAD mice at 4, 6, 8, 10 and 12 months of age and compared to age-matched control animals. Additionally, Aß plaque distribution was assessed in the same mice using [18F]florbetaben at the ages of 2, 5, 7 and 11 months. The results were validated by ex vivo staining of BChE at 4, 8, and 12 months and Aß at 12 months on brain samples. Results: [11C]4 was produced in sufficient radiochemical yield and molar activity for the use in PET imaging. Metabolism and biodistribution studies confirmed sufficient stability in vivo, the ability of [11C]4 to cross the blood brain barrier (BBB) and rapid washout from the brain. Blocking studies confirmed specificity of the binding. Longitudinal PET studies showed increased levels of BChE in the cerebral cortex, hippocampus, striatum, thalamus, cerebellum and brain stem in aged AD mice compared to WT littermates. [18F]Florbetaben-PET imaging showed similar trend of Aß plaques accumulation in the cerebral cortex and the hippocampus of AD animals as the one observed for BChE at ages 4 to 8 months. Contrarily to the results obtained by ex vivo staining, lower abundance of BChE was observed in vivo at 10 and 12 months than at 8 months of age. Conclusions: The BChE inhibitor [11C]4 crosses the BBB and is quickly washed out of the brain of WT mice. Comparison between AD and WT mice shows accumulation of the radiotracer in the AD-affected areas of the brain over time during the early disease progression. The results correspond well with Aß accumulation, suggesting that BChE is a promising early biomarker for incipient AD.