Improved synthesis and application of an alkyne-functionalized isoprenoid analogue to study the prenylomes of motor neurons, astrocytes and their stem cell progenitors.

Protein prenylation is one example of a broad class of post-translational modifications where proteins are covalently linked to various hydrophobic moieties. To globally identify and monitor levels of all prenylated proteins in a cell simultaneously, our laboratory and others have developed chemical proteomic approaches that rely on the metabolic incorporation of isoprenoid analogues bearing bio-orthogonal functionality followed by enrichment and subsequent quantitative proteomic analysis. Here, several improvements in the synthesis of the alkyne-containing isoprenoid analogue C15AlkOPP are reported to improve synthetic efficiency. Next, metabolic labeling with C15AlkOPP was optimized to obtain useful levels of metabolic incorporation of the probe in several types of primary cells. Those conditions were then used to study the prenylomes of motor neurons (ES-MNs), astrocytes (ES-As), and their embryonic stem cell progenitors (ESCs), which allowed for the identification of 54 prenylated proteins from ESCs, 50 from ES-MNs, and 84 from ES-As, representing all types of prenylation. Bioinformatic analysis revealed specific enriched pathways, including nervous system development, chemokine signaling, Rho GTPase signaling, and adhesion. Hierarchical clustering showed that most enriched pathways in all three cell types are related to GTPase activity and vesicular transport. In contrast, STRING analysis showed significant interactions in two populations that appear to be cell type dependent. The data provided herein demonstrates that robust incorporation of C15AlkOPP can be obtained in ES-MNs and related primary cells purified via magnetic-activated cell sorting allowing the identification and quantification of numerous prenylated proteins. These results suggest that metabolic labeling with C15AlkOPP should be an effective approach for investigating the role of prenylated proteins in primary cells in both normal cells and disease pathologies, including ALS.

Improved synthesis and application of an alkyne-functionalized isoprenoid analogue to study the prenylomes of motor neurons, astrocytes and their stem cell progenitors.

Protein prenylation is one example of a broad class of post-translational modifications where proteins are covalently linked to various hydrophobic moieties. To globally identify and monitor levels of all prenylated proteins in a cell simultaneously, our laboratory and others have developed chemical proteomic approaches that rely on the metabolic incorporation of isoprenoid analogues bearing bio-orthogonal functionality followed by enrichment and subsequent quantitative proteomic analysis. Here, several improvements in the synthesis of the alkyne-containing isoprenoid analogue C15AlkOPP are reported to improve synthetic efficiency. Next, metabolic labeling with C15AlkOPP was optimized to obtain useful levels of metabolic incorporation of the probe in several types of primary cells. Those conditions were then used to study the prenylomes of motor neurons (ES-MNs), astrocytes (ES-As), and their embryonic stem cell progenitors (ESCs), which allowed for the identification of 54 prenylated proteins from ESCs, 50 from ES-MNs and 84 from ES-As, representing all types of prenylation. Bioinformatic analysis revealed specific enriched pathways, including nervous system development, chemokine signaling, Rho GTPase signaling, and adhesion. Hierarchical clustering showed that most enriched pathways in all three cell types are related to GTPase activity and vesicular transport. In contrast, STRING analysis showed significant interactions in two populations that appear to be cell type dependent. The data provided herein demonstrates that robust incorporation of C15AlkOPP can be obtained in ES-MNs and related primary cells purified via magnetic-activated cell sorting allowing the identification and quantification of numerous prenylated proteins. These results suggest that metabolic labeling with C15AlkOPP should be an effective approach for investigating the role of prenylated proteins in primary cells in both normal cells and disease pathologies, including ALS.

AAV-Mediated Delivery of Plakophilin-2a Arrests Progression of Arrhythmogenic Right Ventricular Cardiomyopathy in Murine Hearts: Preclinical Evidence Supporting Gene Therapy in Humans.

BACKGROUND: Pathogenic variants in PKP2 (plakophilin-2) cause arrhythmogenic right ventricular cardiomyopathy, a disease characterized by life-threatening arrhythmias and progressive cardiomyopathy leading to heart failure. No effective medical therapy is available to prevent or arrest the disease. We tested the hypothesis that adeno-associated virus vector-mediated delivery of the human PKP2 gene to an adult mammalian heart deficient in PKP2 can arrest disease progression and significantly prolong survival. METHODS: Experiments were performed using a PKP2-cKO (cardiac-specific, tamoxifen-activated PKP2 knockout murine model). The potential therapeutic, adeno-associated virus vector of serotype rh.74 (AAVrh.74)-PKP2a (PKP2 variant A; RP-A601) is a recombinant AAVrh.74 gene therapy viral vector encoding the human PKP2 variant A. AAVrh.74-PKP2a was delivered to adult mice by a single tail vein injection either before or after tamoxifen-activated PKP2-cKO. PKP2 expression was confirmed by molecular and histopathologic analyses. Cardiac function and disease progression were monitored by survival analyses, echocardiography, and electrocardiography. RESULTS: Consistent with prior findings, loss of PKP2 expression caused 100% mortality within 50 days after tamoxifen injection. In contrast, AAVrh.74-PKP2a-mediated PKP2a expression resulted in 100% survival for >5 months (at study termination). Echocardiographic analysis revealed that AAVrh.74-PKP2a prevented right ventricle dilation, arrested left ventricle functional decline, and mitigated arrhythmia burden. Molecular and histological analyses showed AAVrh.74-PKP2a-mediated transgene mRNA and protein expression and appropriate PKP2 localization at the cardiomyocyte intercalated disc. Importantly, the therapeutic benefit was shown in mice receiving AAVrh.74-PKP2a after disease onset. CONCLUSIONS: These preclinical data demonstrate the potential for AAVrh.74-PKP2a (RP-A601) as a therapeutic for PKP2-related arrhythmogenic right ventricular cardiomyopathy in both early and more advanced stages of the disease.

Magnitude and Impact of Workplace Violence Against Obstetric Healthcare Personnel: A Multicentre Cross-Sectional Study.

Background: Workplace violence is defined by the World Health Organization (WHO) as incidents where staff is abused, threatened or assaulted in work settings. In emergency predominated branch like obstetrics, there is a need to study the magnitude and impact of violence against healthcare workers (HCW). Materials and Methodology: This cross-sectional study was conducted in the Department of Obstetrics at 2 centres in Lucknow district, for a period of 6 months. The study population included trainee residents, senior residents, nursing staff and consultants. Standard definitions from the WHO were used to define the types of violence. The validated questionnaire was designed in English with 25 questions to understand the incidence of workplace violence, prevention policy, reporting and follow-ups of incidents and impact of violence. Results: With a response rate of 90%, 274 HCW participated in the study. In total, 172 HCW (62.7%) either faced physical or verbal assault. In 70% of incidents, patient, their relatives or public were perpetrators of violence, and the rest 30% incidents were by colleagues or management. Majority of the incidents were in emergency areas. Only 22% of the abused reported to the concerned authorities. At least 123 (71.5%) HCW were extremely dissatisfied with the action taken. Action was taken against only 9.8% of the perpetrators. None of the respondents received any training to handle workplace violence. Conclusion: There is an alarming high prevalence of workplace violence by patients and colleagues. Adequate training to handle these incidents, improvement of working environment and unconditional support from management will bring a positive work experience. Supplementary Information: The online version contains supplementary material available at 10.1007/s13224-023-01809-0.

An Approach to Evaluate Pb Tolerance and Its Removal Mechanisms by Pleurotus opuntiae.

Widespread lead (Pb) contamination prompts various environmental problems and accounts for about 1% of the global disease burden. Thus, it has necessitated the demand for eco-friendly clean-up approaches. Fungi provide a novel and highly promising approach for the remediation of Pb-containing wastewater. The current study examined the mycoremediation capability of a white rot fungus, P. opuntiae, that showed effective tolerance to increasing concentrations of Pb up to 200 mg L-1, evidenced by the Tolerance Index (TI) of 0.76. In an aqueous medium, the highest removal rate (99.08%) was recorded at 200 mg L-1 whereas intracellular bioaccumulation also contributed to the uptake of Pb in significant amounts with a maximum of 24.59 mg g-1. SEM was performed to characterize the mycelium, suggesting changes in the surface morphology after exposure to high Pb concentrations. LIBS indicated a gradual change in the intensity of some elements after exposure to Pb stress. FTIR spectra displayed many functional groups including amides, sulfhydryl, carboxyl, and hydroxyl groups on the cell walls that led to binding sites for Pb and indicated the involvement of these groups in biosorption. XRD analysis unveiled a mechanism of biotransformation by forming a mineral complex as PbS from Pb ion. Further, Pb fostered the level of proline and MDA at a maximum relative to the control, and their concentration reached 1.07 µmol g-1 and 8.77 nmol g-1, respectively. High Pb concentration results in oxidative damage by increasing the production of ROS. Therefore, the antioxidant enzyme system provides a central role in the elimination of active oxygen. The enzymes, namely SOD, POD, CAT, and GSH, served as most responsive to clear away ROS and lower the stress. The results of this study suggested that the presence of Pb caused no visible adverse symptoms in P. opuntiae. Moreover, biosorption and bioaccumulation are two essential approaches involved in Pb removal by P. opuntiae and are established as worthwhile agents for the remediation of Pb from the environment.

Beta glucan as an immune stimulant in tumor microenvironment - Insight into lessons and promises from past decade.

Cancer is characterized by a perturbed immune landscape. Inside tumor microenvironment, immune system is reprogrammed to facilitate tumor growth and survival rather than eliminating it. This immune evasive mechanism needs to be reversed to normal for effective anticancer therapeutic strategy. Immunotherapy has emerged as a novel strategy for redeployment of immune cells against cancer. However, they suffer in their efficacy, response rate and side effects. This necessitated us to turn toward natural repertoires which can act as a substitute to conventional immunotherapeutics. Beta glucan, a polysaccharide derived from mushroom, serves the role of immunomodulator inside tumor microenvironment. It acts as pathogen associated molecular pattern and bind to various pattern recognition receptors expressed on surface of immune cells thereby facilitating their activation and crosstalk. This result in resurgence of suppressed immune surveillance in the tumor milieu. In this review, we highlight in brief the advances and limitation of cancer immunotherapy. Alongside, we have discussed the detailed mechanistic principle and recent advances underlying restoration of immune functionality by beta glucan.

Bioengineered Ciprofloxacin-Loaded Chitosan Nanoparticles for the Treatment of Bovine Mastitis.

Mastitis is the most devastating economic disease in dairy cattle. Mastitis in dairy cattle frequently occurs during the dry period or during early lactation. Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus)are the main causative agents of mastitis in India. S. aureus can form microabscesses in the udder and develop a subclinical form of mastitis. This bacterial property hinders an effective cure during the lactation period. Antimicrobials used for treatments have a short half-life at the site of action because of frequent milking; thereforethey are unable to maintain the desired drug concentration for effective clearance of bacteria. We demonstrated the potential of ciprofloxacin-encapsulated nanocarriersthat can improve the availability of drugs and provide an effective means for mastitis treatment. These drug-loaded nanoparticles show low toxicity and slow clearance from the site of action. Antimicrobial activity against clinical strains of E. coli and S. aureus showed that the zone of inhibition depended on the dose (0.5 mg to 2 mg/mL nanoparticle solution from 11.6 to 14.5 mm and 15 to 18 mm). These nanoparticles showed good antimicrobial activity in broth culture and agar diffusion assay against bacteria.

Elemental Analysis, Phytochemical Screening and Evaluation of Antioxidant, Antibacterial and Anticancer Activity of Pleurotus ostreatus through In Vitro and In Silico Approaches.

Oyster mushrooms form an integral part of many diets owing to their characteristic aroma, delicious taste and nutraceutical value. In this study, we examined oyster mushrooms by direct arc optical emission spectroscopy for the presence of various biologically important elements. Furthermore, we screened phytochemicals present in Pleurotus ostreatus by applying GC-MS. Additionally, the antioxidant, antibacterial and anticancer activities of the ethanolic extract of Pleurotus ostreatus were studied. Moreover, we docked the phytochemicals and examined their binding affinities with EGFR, PR and NF-κB proteins, which are overexpressed in breast cancer. The elemental analysis showed the presence of Fe, K, Na, Ca, Mg, Cr and Sr in the spectrum. Moreover, GC-MS data revealed the presence of 32 biologically active compounds in oyster mushrooms. The ethanolic extract displayed remarkable free radical scavenging activity (~50%) against DPPH. The mushroom has shown promising antibacterial activity against both Gram-positive (S. aureus) and Gram-negative bacteria (Pseudomonasaeruginosa, Proteus vulgaris and Proteus mirabilis). The present study also revealed that oyster mushrooms possess significant anticancer activity. The ethanolic extract inhibited the growth and proliferation of MCF-7 cells. It also induced cell shrinkage, membrane blebbing and nuclear fragmentation, resulting in apoptosis of malignant cells. The molecular docking analysis showed that ligand 15 (Linoleic acid ethyl ester), ligand 27 (Ergosta-5,7,9(11),22-tetraen-3-ol, (3. beta.,22E), ligand 28 (Stigmasta-5,22-dien-3-ol, acetate, (3. beta.,22Z), ligand 30 (Ergosta-5,7,22-Trien-3-Ol, (3. Beta.,22E) and ligand 32 (gamma. Sitosterol) exhibited better binding affinities with EGFR, PR and NF-κB proteins. This result provides a strong ground for confirmation of the in vitro anticancer effect of Pleurotus ostreatus. From the present in vitro and in silico studies, it can be concluded that Pleurotus ostreatus is a useful source of essential elements and reservoir of bioactive compounds which confer its significant antioxidant, antibacterial and anticancer properties.

Retromer dysfunction in amyotrophic lateral sclerosis.

Retromer is a heteropentameric complex that plays a specialized role in endosomal protein sorting and trafficking. Here, we report a reduction in the retromer proteins-vacuolar protein sorting 35 (VPS35), VPS26A, and VPS29-in patients with amyotrophic lateral sclerosis (ALS) and in the ALS model provided by transgenic (Tg) mice expressing the mutant superoxide dismutase-1 G93A. These changes are accompanied by a reduction of levels of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor subunit GluA1, a proxy of retromer function, in spinal cords from Tg SOD1G93A mice. Correction of the retromer deficit by a viral vector expressing VPS35 exacerbates the paralytic phenotype in Tg SOD1G93A mice. Conversely, lowering Vps35 levels in Tg SOD1G93A mice ameliorates the disease phenotype. In light of these findings, we propose that mild alterations in retromer inversely modulate neurodegeneration propensity in ALS.

Immobilization of catalase on functionalized magnetic nanoparticles: a statistical approach.

Magnetic nanoparticles (MNPs) Fe3O4, by virtue of easily modifiable surface, high surface-to-mass ratio and super-paramagnetic properties, are one of suitable candidates for the enzyme immobilization. Optimization of five important variables viz. concentration of 3-aminopropyl-tri-ethoxy-silane (APTES), glutaraldehyde (GA) and enzyme, time and temperature of loading was carried out using central composite type of experimental design without blocks giving 50 experiments including eight replicates at the central point. Characterization, stability and reusability studies were also carried out with optimized preparation. Results established the correlation between observed and response surface method (RSM) equation envisaged value (R 2 0.99, 0.97 and 0.98 for enzyme's activity, its loading over MNPs and corresponding specific activity, respectively. The predicted values suggested by RSM equation were 64.00 mM of APTES, 10.97 µL of GA, 14.50 mg mL-1 of enzyme for 67 min at 22.6 °C, resulted in activity 32.1 U mg-1 MNPs, while specific activity was 97.7 U mg-1. Transmission electron microscopy (TEM) showed the sizes of MNPs (10.5 ± 1.7 nm), APTES-MNPs (10.23 ± 1.74 nm), GA-APTES-MNPs (11.84 ± 1.49 nm) and Catalase-GA-APTES-MNPs (13.32 ± 2.74 nm) were statistically similar. The enzyme MNPs preparation retained 81.65% activity after 144 h at 4 °C (free enzyme retained 7.87%) and 64.34% activity after 20 reuse cycles. Statistical optimized MNPs-based catalase preparation with high activity and magnetic strength was stable and can be used for further studies related to its application as analytical recyclable enzyme or magnetically oriented delivery in the body. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-022-03173-8.

Promising anticancer activity of polysaccharides and other macromolecules derived from oyster mushroom (Pleurotus sp.): An updated review.

Cancer dominates among many causes of mortality worldwide. Traditional chemotherapeutic agents are powerful anti-cancer agents employed for treatment of this deadly disease. However, they are always associated with toxic side effects and immunosuppression making person more vulnerable to tumor relapse and fatalities. A promising alternative could be identification, isolation and transfer of naturally occurring bioactive macromolecules to the tumorigenic population. Oyster mushroom, a major source of nutraceuticals, belonging to class basidiomycetes of kingdom Mycota is known to have immense therapeutic properties. It is a reservoir of macromolecules like ß-glucan, α-glucan, resveratrol, concanavalin A, cibacron blue affinity protein, p-hydroxybenzoic acid, ergosterol, linoleic acid etc. that are responsible for mediating anti-tumor, immunomodulatory, antioxidant, and anti-diabetic roles. Various studies have shown that extracts derived from oyster mushroom is rich in polysaccharides like ß-glucan and other macro molecules which have an anti-proliferative effect against cancer cell lines, without harming the normal cells. This review presents a brief highlight of the work covering the overall significance of oyster mushroom in different types of cancer treatment. It also explores the immunomodulatory effects of polysaccharides, proteoglycans and polypeptides derived from oyster mushroom that boosts the immune system to overcome the limitation of traditional cancer therapies.

Systematic elucidation of neuron-astrocyte interaction in models of amyotrophic lateral sclerosis using multi-modal integrated bioinformatics workflow.

Cell-to-cell communications are critical determinants of pathophysiological phenotypes, but methodologies for their systematic elucidation are lacking. Herein, we propose an approach for the Systematic Elucidation and Assessment of Regulatory Cell-to-cell Interaction Networks (SEARCHIN) to identify ligand-mediated interactions between distinct cellular compartments. To test this approach, we selected a model of amyotrophic lateral sclerosis (ALS), in which astrocytes expressing mutant superoxide dismutase-1 (mutSOD1) kill wild-type motor neurons (MNs) by an unknown mechanism. Our integrative analysis that combines proteomics and regulatory network analysis infers the interaction between astrocyte-released amyloid precursor protein (APP) and death receptor-6 (DR6) on MNs as the top predicted ligand-receptor pair. The inferred deleterious role of APP and DR6 is confirmed in vitro in models of ALS. Moreover, the DR6 knockdown in MNs of transgenic mutSOD1 mice attenuates the ALS-like phenotype. Our results support the usefulness of integrative, systems biology approach to gain insights into complex neurobiological disease processes as in ALS and posit that the proposed methodology is not restricted to this biological context and could be used in a variety of other non-cell-autonomous communication mechanisms.

Deletion of Ripk3 Prevents Motor Neuron Death In Vitro but not In Vivo.

Increasing evidence suggests that necroptosis, a form of programmed cell death (PCD), contributes to neurodegeneration in several disorders, including ALS. Supporting this view, investigations in both in vitro and in vivo models of ALS have implicated key molecular determinants of necroptosis in the death of spinal motor neurons (MNs). Consistent with a pathogenic role of necroptosis in ALS, we showed increased mRNA levels for the three main necroptosis effectors Ripk1, Ripk3, and Mlkl in the spinal cord of mutant superoxide dismutase-1 (SOD1G93A) transgenic mice (Tg), an established model of ALS. In addition, protein levels of receptor-interacting protein kinase 1 (RIPK1; but not of RIPK3, MLKL or activated MLKL) were elevated in spinal cord extracts from these Tg SOD1G93A mice. In postmortem motor cortex samples from sporadic and familial ALS patients, no change in protein levels of RIPK1 were detected. Silencing of Ripk3 in cultured MNs protected them from toxicity associated with SOD1G93A astrocytes. However, constitutive deletion of Ripk3 in Tg SOD1G93A mice failed to provide behavioral or neuropathological improvement, demonstrating no similar benefit of Ripk3 silencing in vivo. Lastly, we detected no genotype-specific myelin decompaction, proposed to be a proxy of necroptosis in ALS, in either Tg SOD1G93A or Optineurin knock-out mice, another ALS mouse model. These findings argue against a role for RIPK3 in Tg SOD1G93A-induced neurodegeneration and call for further preclinical investigations to determine if necroptosis plays a critical role in the pathogenesis of ALS.

Fungal pretreatment of sweet sorghum bagasse with supplements: improvement in lignin degradation, selectivity and enzymatic saccharification.

Sweet sorghum bagasse (SSB) from food processing and agricultural industry has attracted the attention for uses in production of biofuel, enzymes and other products. The alteration in lignocellulolytic enzymes by use of supplements in fungal pretreatment of SSB to achieve higher lignin degradation, selectivity value and enzymatic hydrolysis to fermentable sugar was studied. Fungal strain Coriolus versicolor was selected for pretreatment due to high ligninolytic and low cellulolytic enzyme production resulting in high lignin degradation and selectivity value. SSB was pretreated with supplements of veratryl alcohol, syringic acid, catechol, gallic acid, vanillin, guaiacol, CuSO4 and MnSO4. The best results were obtained with CuSO4, gallic acid and syringic acid supplements. CuSO4 increased the activities of laccase (4.9-fold) and polyphenol oxidase (1.9-fold); gallic acid increased laccase (3.5-fold) and manganese peroxidase (2.5-fold); and syringic acid increased laccase (5.6-fold), lignin peroxidase (13-fold) and arylalcohol oxidase (2.8-fold) resulting in enhanced lignin degradations and selectivity values than the control. Reduced cellulolytic enzyme activities resulted in high cellulose recovery. Enzymatic hydrolysis of pretreated SSB yielded higher sugar due to degradation of lignin and reduced the crystallinity of cellulose. The study showed that supplements could be used to improve the pretreatment process. The results were confirmed by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and thermogravimetric/differential thermogravimetric analysis of SSB.

Enhancement in multiple lignolytic enzymes production for optimized lignin degradation and selectivity in fungal pretreatment of sweet sorghum bagasse.

The objective of this work was to study the increase in multiple lignolytic enzyme productions through the use of supplements in combination in pretreatment of sweet sorghum bagasse (SSB) by Coriolus versicolor such that enzymes act synergistically to maximize the lignin degradation and selectivity. Enzyme activities were enhanced by metallic salts and phenolic compound supplements in SSF. Supplement of syringic acid increased the activities of LiP, AAO and laccase; gallic acid increased MnP; CuSO4 increased laccase and PPO to improve the lignin degradations and selectivity individually, higher than control. Combination of supplements optimized by RSM increased the production of laccase, LiP, MnP, PPO and AAO by 17.2, 45.5, 3.5, 2.4 and 3.6 folds respectively for synergistic action leading to highest lignin degradation (2.3 folds) and selectivity (7.1 folds). Enzymatic hydrolysis of pretreated SSB yielded ∼2.43 times fermentable sugar. This technique could be widely applied for pretreatment and enzyme productions.

Improvement of selective lignin degradation in fungal pretreatment of sweet sorghum bagasse using synergistic CuSO4-syringic acid supplements.

Sweet sorghum bagasse (SSB) generated in large quantities could be hydrolyzed to sugar and then fermented to green fuels. The hydrolysis of SSB polysaccharides interlocked in recalcitrant lignin network is the major problem. Pretreatment of SSB in SSF by using Coriolus versicolor with CuSO4-syringic acid supplements for effects on production of ligninocellulolytic enzymes, lignin degradation and selectivity values (SV) were studied. C. versicolor was selected based on high ligninolytic and low cellulolytic abilily. Individually, CuSO4 increased the activities of laccase (4.9 folds) and PPO (1.9 folds); syringic acid increased LiP (13 folds), AAO (2.8 folds) and laccase (5.6 folds) resulting in increased lignin degradation and SVs. Combined syringic acid (4.4 µmol g-1 SSB) and CuSO4 (4.4 µmol g-1 SSB) increased the activities of laccase, LiP, MnP, PPO and AAO by 11.2, 17.6, 2.8, 2.4 and 2.3 folds respectively due to synergistic effect, resulting in maximum lignin degradation 35.9 ± 1.3% (w w-1) (1.86 fold) and highest SV 3.07 (4.7 fold). Enzymatic hydrolysis of pretreated SSB yielded higher (∼2.2 times) fermentable sugar. Pretreated SSB was characterized by XRD, SEM, FTIR and TGA/DTG analysis to confirm results. It is possible to improve fungal pretreatment of agricultural waste by combination of supplements.

Fungal Pretreatment of Sweet Sorghum Bagasse with Combined CuSO4-Gallic Acid Supplement for Improvement in Lignin Degradation, Selectivity, and Enzymatic Saccharification.

Sweet sorghum (Sorghum sp.) has high biomass yield. Hydrolysis of lignocellulosic sweet sorghum bagasse (SSB) to fermentable sugar could be useful for manufacture of biofuel or other fermentation products. Pretreatment of lignocellulosic biomass to degrade lignin before enzymatic hydrolysis is a key step. Fungal pretreatment of SSB with combined CuSO4-gallic acid supplements in solid-state fermentation (SSF) to achieve higher lignin degradation, selectivity value (SV), and enzymatic hydrolysis to sugar was studied. Coriolus versicolor was selected due to high activities of ligninolytic enzymes laccase, lignin peroxidase (LiP), manganese peroxidase (MnP), polyphenol oxidase (PPO), and arylalcohol oxidase (AAO) and low activities of cellulolytic enzymes CMCase, FPase, and ß-glucosidase with high lignin degradation and SV in 20 days. CuSO4/gallic acid increased the activities of ligninolytic enzymes resulting in enhanced lignin degradations and SVs. Cumulative/synergistic effect of combined supplements further increased the activities of laccase, LiP, MnP, PPO, and AAO by 7.6, 14.6, 2.67, 2.06, and 2.15-folds, respectively (than control), resulting in highest lignin degradation 31.1 ± 1.4% w/w (1.56-fold) and SV 2.33 (3.58-fold). Enzymatic hydrolysis of pretreated SSB yielded higher (~2.2 times) fermentable sugar. The study showed combined supplements can improve fungal pretreatment of lignocellulosic biomass. XRD, SEM, FTIR, and TGA/DTG of SSB confirmed the results.

Synergistic effects of Arbuscular mycorrhizal fungi and plant growth promoting rhizobacteria in bioremediation of iron contaminated soils.

Three Arbuscular mycorrhizal fungi (AMF) from Glomus, Acaulospora and Scutellospora, and four plant growth promoting rhizobacteria (PGPR) isolates related to genera Streptomyces, Azotobacter, Pseudomonas and Paenibacillus were found to be effective in phytoremediation of Fe(3+) contaminated soil where Pennisetum glaucum and Sorghum bicolor were growing as host plants. Co-inoculation of AMF and PGPR showed better results in comparison to either, AMF and PGPR under pot conditions. Both AMF and PGPR were able to produce siderophores. AMF and PGPR associated to P. glaucum and S. bicolor plants increased the extent of iron absorption. AMF and PGPR combination exhibited superior (p < 0.01) phytoremediation efficiency with P. glaucum compared to S. bicolor. These findings warrant further investigations of these synergistic interactions and large-scale in situ studies for bioremediation of iron-contaminated soils.

Effects of impaired membrane interactions on α-synuclein aggregation and neurotoxicity.

The post-mortem brains of individuals with Parkinson's disease (PD) and other synucleinopathy disorders are characterized by the presence of aggregated forms of the presynaptic protein α-synuclein (aSyn). Understanding the molecular mechanism of aSyn aggregation is essential for the development of neuroprotective strategies to treat these diseases. In this study, we examined how interactions between aSyn and phospholipid vesicles influence the protein's aggregation and toxicity to dopaminergic neurons. Two-dimensional NMR data revealed that two familial aSyn mutants, A30P and G51D, populated an exposed, membrane-bound conformer in which the central hydrophobic region was dissociated from the bilayer to a greater extent than in the case of wild-type aSyn. A30P and G51D had a greater propensity to undergo membrane-induced aggregation and elicited greater toxicity to primary dopaminergic neurons compared to the wild-type protein. In contrast, the non-familial aSyn mutant A29E exhibited a weak propensity to aggregate in the presence of phospholipid vesicles or to elicit neurotoxicity, despite adopting a relatively exposed membrane-bound conformation. Our findings suggest that the aggregation of exposed, membrane-bound aSyn conformers plays a key role in the protein's neurotoxicity in PD and other synucleinopathy disorders.

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is selectively toxic to primary dopaminergic neurons in vitro.

Parkinson's disease (PD) is the second most common neurodegenerative disease. Much data has linked the etiology of PD to a variety of environmental factors. The majority of cases are thought to arise from a combination of genetic susceptibility and environmental factors. Chronic exposures to dietary factors, including meat, have been identified as potential risk factors. Although heterocyclic amines that are produced during high-temperature meat cooking are known to be carcinogenic, their effect on the nervous system has yet to be studied in depth. In this study, we investigated neurotoxic effects of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), a highly abundant heterocyclic amine in cooked meat, in vitro. We tested toxicity of PhIP and the two major phase I metabolites, N-OH-PhIP and 4'-OH-PhIP, using primary mesencephalic cultures from rat embryos. This culture system contains both dopaminergic and nondopaminergic neurons, which allows specificity of neurotoxicity to be readily examined. We find that exposure to PhIP or N-OH-PhIP is selectively toxic to dopaminergic neurons in primary cultures, resulting in a decreased percentage of dopaminergic neurons. Neurite length is decreased in surviving dopaminergic neurons. Exposure to 4'-OH-PhIP did not produce significant neurotoxicity. PhIP treatment also increased formation of oxidative damage markers, 4-hydroxy-2-nonenal (HNE) and 3-nitrotyrosine in dopaminergic neurons. Pretreatment with N-acetylcysteine was protective. Finally, treatment with blueberry extract, a dietary factor with known antioxidant and other protective mechanisms, prevented PhIP-induced toxicity. Collectively, our study suggests, for the first time, that PhIP is selectively toxic to dopaminergic neurons likely through inducing oxidative stress.