Enhanced low-cost lipopeptide biosurfactant production by Bacillus velezensis from residual glycerin.

Biosurfactants (BSFs) are molecules produced by microorganisms from various carbon sources, with applications in bioremediation and petroleum recovery. However, the production cost limits large-scale applications. This study optimized BSFs production by Bacillus velezensis (strain MO13) using residual glycerin as a substrate. The spherical quadratic central composite design (CCD) model was used to standardize carbon source concentration (30 g/L), temperature (34 °C), pH (7.2), stirring (239 rpm), and aeration (0.775 vvm) in a 5-L bioreactor. Maximum BSFs production reached 1527.6 mg/L of surfactins and 176.88 mg/L of iturins, a threefold increase through optimization. Microbial development, substrate consumption, concentration of BSFs, and surface tension were also evaluated on the bioprocess dynamics. Mass spectrometry Q-TOF-MS identified five surfactin and two iturin isoforms produced by B. velezensis MO13. This study demonstrates significant progress on BSF production using industrial waste as a microbial substrate, surpassing reported concentrations in the literature.

Severity of white matter microstructural damage in a Brazilian relapsing-remitting multiple sclerosis cohort: A possible window to optimize treatment.

BACKGROUND: Multiple sclerosis (MS) is an important cause of acquired neurological disability in young adults, characterized by multicentric inflammation, demyelination, and axonal damage. OBJECTIVE: The objective is to investigate white matter (WM) damage progression in a Brazilian MS patient cohort, using diffusion tensor imaging (DTI) post-processed by tract-based spatial statistics (TBSS). METHODS: DTI scans were acquired from 76 MS patients and 37 sex-and-age matched controls. Patients were divided into three groups based on disease duration. DTI was performed along 30 non-collinear directions by using a 1.5T imager. For TBSS analysis, the WM skeleton was created, and a 5000 permutation-based inference with a threshold of p < .05 was used, to enable the identification of abnormalities in fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD). RESULTS: Decreased FA and increased RD, MD, and AD were seen in patients compared to controls and a decreased FA and increased MD and RD were seen, predominantly after the first 5 years of disease, when compared between groups. CONCLUSION: Progressive WM deterioration is seen over time with a more prominent pattern after 5 years of disease onset, providing evidence that the early years might be a window to optimize treatment and prevent disability.

Serum BDNF and cognitive dysfunction in SLE: findings from a cohort of 111 patients.

OBJECTIVE: The association between brain-derived neurotrophic factor (BDNF) and neuropsychiatric systemic lupus erythematosus (NPSLE) is controversial in the literature. Cognitive dysfunction (CD) is a common, underdiagnosed NPSLE manifestation, but its pathophysiology is unknown. Thus, we investigate serum BDNF as a potential biomarker of CD in a cohort of SLE patients. METHODS: We included 63 SLE patients, 48 NPSLE, and 57 age- and gender-matched controls (CON). All participants underwent neuropsychological assessment. Data on cardiovascular comorbidities, SLE disease activity index (SLEDAI), and Systemic Lupus International Collaborating Clinics damage index (SLICC-DI) were compiled. Multiple regression analyses evaluated predictors of serum BDNF levels. RESULTS: Serum BDNF levels were lower in SLE and NPSLE patients than in CON (SLE 800.4 ± 502.7 vs. NPSLE 779.7 ± 426.3 vs. CON 1,345.5 ng/mL ± 438.4; p < 0.001). In addition, hypertension (B: - 192.5, SE: 84.3, 95% CI: - 359.7 to - 25.3, p = 0.024) and SLICC-DI score (B: - 75.9, SE: 27.2, 95% CI: - 129.8 to - 22, p = 0.006) were predictors of serum BDNF levels in SLE. There was no relation between BDNF levels and CD. CONCLUSION: BDNF levels are lower in SLE patients than CON and inversely associated with hypertension and SLICC-DI scores. No association between BDNF levels and CD or NPSLE was observed in this cohort. These findings indicate that BDNF may be associated with overall burden in SLE rather than specific manifestations such as cognition impairment. Key Points • BDNF is associated with an overall burden in SLE rather than specific manifestations such as cognition dysfunction. • BDNF levels are reduced in patients with SLE, and higher SLICC-DI scores and hypertension are independent predictors of lower serum BDNF levels. • The cognitive dysfunction rate is elevated (46%) among Brazilian SLE patients.

The role of extracellular nucleic acids in the immune system modulation of Rhodnius prolixus (Hemiptera: Reduviidae).

Extracellular traps (ETs) are extracellular nucleic acids associated with cytoplasmic proteins that may aid in the capture and killing of pathogens. To date, only a few insects were shown to display this kind of immune response. Jaburetox, a peptide derived from jack bean urease, showed toxic effects in Rhodnius prolixus, affecting its immune response. The present study aims to evaluate the role of extracellular nucleic acids in R. prolixus' immune response, using Jaburetox as a model entomotoxin. The insects were treated with extracellular nucleic acids and/or Jaburetox, and the cellular and humoral responses were assessed. We also evaluated the release of extracellular nucleic acids induced by toxins, and performed immunocompetence assays using pathogenic bacteria. Our results demonstrated that extracellular nucleic acids can modulate the insect immune responses, either alone or associated with the toxin. Although RNA and DNA induced a cellular immune response, only DNA was able to neutralize the Jaburetox-induced aggregation of hemocytes. Likewise, the activation of the humoral response was different for RNA and DNA. Nevertheless, it was observed that both, extracellular DNA and RNA, immunocompensated the Jaburetox effects on insect defenses upon the challenge of a pathogenic bacterium. The toxin was not able to alter cellular viability, in spite of inducing an increase in the reactive species of oxygen formation. In conclusion, we have demonstrated a protective role for extracellular nucleic acids in R. prolixus´ immune response to toxins and pathogenic bacteria.

Soyuretox, an Intrinsically Disordered Polypeptide Derived from Soybean (Glycine Max) Ubiquitous Urease with Potential Use as a Biopesticide.

Ureases from different biological sources display non-ureolytic properties that contribute to plant defense, in addition to their classical enzymatic urea hydrolysis. Antifungal and entomotoxic effects were demonstrated for Jaburetox, an intrinsically disordered polypeptide derived from jack bean (Canavalia ensiformis) urease. Here we describe the properties of Soyuretox, a polypeptide derived from soybean (Glycine max) ubiquitous urease. Soyuretox was fungitoxic to Candida albicans, leading to the production of reactive oxygen species. Soyuretox further induced aggregation of Rhodnius prolixus hemocytes, indicating an interference on the insect immune response. No relevant toxicity of Soyuretox to zebrafish larvae was observed. These data suggest the presence of antifungal and entomotoxic portions of the amino acid sequences encompassing both Soyuretox and Jaburetox, despite their small sequence identity. Nuclear Magnetic Resonance (NMR) and circular dichroism (CD) spectroscopic data revealed that Soyuretox, in analogy with Jaburetox, possesses an intrinsic and largely disordered nature. Some folding is observed upon interaction of Soyuretox with sodium dodecyl sulfate (SDS) micelles, taken here as models for membranes. This observation suggests the possibility for this protein to modify its secondary structure upon interaction with the cells of the affected organisms, leading to alterations of membrane integrity. Altogether, Soyuretox can be considered a promising biopesticide for use in plant protection.

Modulation of Disordered Proteins with a Focus on Neurodegenerative Diseases and Other Pathologies.

Intrinsically disordered proteins (IDPs) do not have rigid 3D structures, showing changes in their folding depending on the environment or ligands. Intrinsically disordered proteins are widely spread in eukaryotic genomes, and these proteins participate in many cell regulatory metabolism processes. Some IDPs, when aberrantly folded, can be the cause of some diseases such as Alzheimer's, Parkinson's, and prionic, among others. In these diseases, there are modifications in parts of the protein or in its entirety. A common conformational variation of these IDPs is misfolding and aggregation, forming, for instance, neurotoxic amyloid plaques. In this review, we discuss some IDPs that are involved in neurodegenerative diseases (such as beta amyloid, alpha synuclein, tau, and the "IDP-like" PrP), cancer (p53, c-Myc), and diabetes (amylin), focusing on the structural changes of these IDPs that are linked to such pathologies. We also present the IDP modulation mechanisms that can be explored in new strategies for drug design. Lastly, we show some candidate drugs that can be used in the future for the treatment of diseases caused by misfolded IDPs, considering that cancer therapy has more advanced research in comparison to other diseases, while also discussing recent and future developments in this area of research. Therefore, we aim to provide support to the study of IDPs and their modulation mechanisms as promising approaches to combat such severe diseases.

Default-mode network and deep gray-matter analysis in neuromyelitis optica patients.

OBJECTIVE: The aim of our study was to detect functional changes in default-mode network of neuromyelitis optica (NMO) patients using resting-state functional magnetic resonance images and the evaluation of subcortical gray-matter structures volumes. MATERIALS AND METHODS: NMO patients (n=28) and controls patients (n=19) were enrolled. We used the integrated registration and segmentation tool, part of FMRIB's Software Library (FSL) to segment subcortical structures including the thalamus, caudate nucleus, putamen, hippocampus and amygdalae. Resting-state functional magnetic resonance images were post-processed using the Multivariate Exploratory Linear Optimized Decomposition into Independent Components, also part of FSL. Average Z-values extracted from the default-mode network were compared between patients and controls using t-tests (P values <0.05 were considered statistically significant). RESULTS: There were areas of increased synchronization in the default-mode network of patients compared to controls, notably in the precuneus and right hippocampus (corrected P<0.01). The frontal area had decreased synchronization in patients compared to controls (corrected P<0.01). There were no observed differences between patients and controls in subcortical volumes or average Z-values values for default-mode network. CONCLUSION: The hyperactivity of certain default-mode network areas may reflect cortical compensation for subtle structural damage in NMO patients.

Structural analysis of the interaction between Jaburetox, an intrinsically disordered protein, and membrane models.

Jack bean urease is entomotoxic to insects with cathepsin-like digestive enzymes, and its toxicity is mainly caused by a polypeptide called Jaburetox (Jbtx), released by cathepsin-dependent hydrolysis of the enzyme. Jbtx is intrinsically disordered in aqueous solution, as shown by CD and NMR. Jbtx is able to alter the permeability of membranes, hinting to a role of Jbtx-membrane interaction as the basis for its toxicity. The present study addresses the structural aspects of this interaction by investigating the behaviour of Jbtx when in contact with membrane models, using nuclear magnetic resonance and circular dichroism spectroscopies in the absence or presence of micelles, large unilamellar vesicles, and bicelles. Fluorescence microscopy was also used to detect protein-insect membrane interaction. Significant differences were observed depending on the type of membrane model used. The interaction with negatively charged SDS micelles increases the secondary and tertiary structure content of the polypeptide, while, in the case of large unilamellar vesicles and bicelles, conformational changes were observed at the terminal regions, with no significant acquisition of secondary structure motifs. These results were interpreted as suggesting that the Jbtx-lipids interaction anchors the polypeptide to the cellular membrane through the terminal portions of the polypeptide and that, following this interaction, Jbtx undergoes conformational changes to achieve a more ordered structure that could facilitate its interaction with membrane-bound proteins. Consistently with this hypothesis, the presence of these membrane models decreases the ability of Jbtx to bind cellular membranes of insect nerve cord. The collected evidence from these studies implies that the biological activity of Jbtx is due to protein-phospholipid interactions.

Bacillus spp. Isolated from Puba as a Source of Biosurfactants and Antimicrobial Lipopeptides.

Several products of industrial interest are produced by Bacillus, including enzymes, antibiotics, amino acids, insecticides, biosurfactants and bacteriocins. This study aimed to investigate the potential of two bacterial isolates (P5 and C3) from puba, a regional fermentation product from cassava, to produce multiple substances with antimicrobial and surface active properties. Phylogenetic analyses showed close relation of isolates P5 and C3 with Bacillus amyloliquefaciens and Bacillus thuringiensis, respectively. Notably, Bacillus sp. P5 showed antimicrobial activity against pathogens such as Listeria monocytogenes and Bacillus cereus, in addition to antifungal activity. The presence of genes encoding pre-subtilosin (sboA), malonyl CoA transacylase (ituD), and the putative transcriptional terminator of surfactin (sfp) were detected in Bacillus sp. P5, suggesting the production of the bacteriocin subtilosin A and the lipopeptides iturin A and surfactin by this strain. For Bacillus sp. C3 the presence of sboA and spas (subtilin) genes was observed by the first time in members of B. cereus cluster. Bacillus sp. P5 showed emulsifying capability on mineral oil, soybean biodiesel and toluene, while Bacillus sp. C3 showed emulsifying capability only on mineral oil. The reduction of the surface tension in culture medium was also observed for strain P5, confirming the production of surface-active compounds by this bacterium. Monoprotonated molecular species and adducts of sodium and potassium ions of surfactin, iturin, and fengycin were detected in the P5 culture medium. Comparative MS/MS spectra of the peak m/z 1030 (C14 surfactin A or C15 surfactin B [M+Na]+) and peak m/z 1079 (C15 iturin [M+Na]+) showed the same fragmentation profile of standards, confirming the molecular identification. In conclusion, Bacillus sp. P5 showed the best potential for the production of antifungal, antibacterial, and biosurfactant substances.

Humoral and cellular immune responses induced by the urease-derived peptide Jaburetox in the model organism Rhodnius prolixus.

BACKGROUND: Although the entomotoxicity of plant ureases has been reported almost 20 years ago, their insecticidal mechanism of action is still not well understood. Jaburetox is a recombinant peptide derived from one of the isoforms of Canavalia ensiformis (Jack Bean) urease that presents biotechnological interest since it is toxic to insects of different orders. Previous studies of our group using the Chagas disease vector and model insect Rhodnius prolixus showed that the treatment with Jack Bean Urease (JBU) led to hemocyte aggregation and hemolymph darkening, among other effects. In this work, we employed cell biology and biochemical approaches to investigate whether Jaburetox would induce not only cellular but also humoral immune responses in this species. RESULTS: The findings indicated that nanomolar doses of Jaburetox triggered cation-dependent, in vitro aggregation of hemocytes of fifth-instar nymphs and adults. The use of specific eicosanoid synthesis inhibitors revealed that the cellular immune response required cyclooxygenase products since indomethacin prevented the Jaburetox-dependent aggregation whereas baicalein and esculetin (inhibitors of the lipoxygenases pathway) did not. Cultured hemocytes incubated with Jaburetox for 24 h showed cytoskeleton disorganization, chromatin condensation and were positive for activated caspase 3, an apoptosis marker, although their phagocytic activity remained unchanged. Finally, in vivo treatments by injection of Jaburetox induced both a cellular response, as observed by hemocyte aggregation, and a humoral response, as seen by the increase of spontaneous phenoloxidase activity, a key enzyme involved in melanization and defense. On the other hand, the humoral response elicited by Jaburetox injections did not lead to an increment of antibacterial or lysozyme activities. Jaburetox injections also impaired the clearance of the pathogenic bacteria Staphylococcus aureus from the hemolymph leading to increased mortality, indicating a possible immunosuppression induced by treatment with the peptide. CONCLUSIONS: In our experimental conditions and as part of its toxic action, Jaburetox activates some responses of the immune system of R. prolixus both in vivo and in vitro, although this induction does not protect the insects against posterior bacterial infections. Taken together, these findings contribute to the general knowledge of insect immunity and shed light on Jaburetox's mechanism of action.

Effect of pH and interaction between egg white protein and hydroxypropymethylcellulose in bulk aqueous medium on foaming properties.

Egg white protein (EW) is used as surface-active ingredient in aerated food and hydroxypropylmethylcellulose (HPMC) is a polysaccharide that behaves as a surfactant. This study aimed at investigating the effects of process parameters biopolymer concentration (2.0-5.0%, w/w), EW:HPMC ratio (2:1-18:1), pH (3.0-6.0), and the influence of biopolymers' behavior in aqueous solution at different pH on the foaming properties (overrun, drainage, and bubble growth rate). Process parameters had effect on foaming properties. The pH was the major factor influencing the type of EW/HPMC interaction and affected the foaming properties of biopolymer mixture. At pH 3.0, EW and HPMC showed thermodynamic compatibility leading to better foaming properties, higher foaming capacity, and stability than without HPMC addition whereas at pH 4.5 and 6.0, EW and HPMC are incompatible that causes lower stability concerning the disproportionation comparing to foam without HPMC. At pH between 3.0 and 4.5, HPMC improves foaming properties of aerated products.

Pliable natural biocide: Jaburetox is an intrinsically disordered insecticidal and fungicidal polypeptide derived from jack bean urease.

Jaburetox is a polypeptide derived from jack bean (Canavalia ensiformis) urease and toxic to a broad spectrum of insects, phytopathogenic filamentous fungi and yeasts of medical importance. The elucidation of the structural basis for the mode of action of Jaburetox is the focus of this multifaceted study. Jaburetox in solution is a monomer of 11.0 kDa featuring a large hydrodynamic radius, suggestive of a disordered polypeptide. The intrinsically disordered nature of Jaburetox was theoretically predicted by a comprehensive bioinformatics analysis and experimentally confirmed by light scattering as well as by circular dichroism and NMR spectroscopy. NMR signal assignment provided backbone secondary chemical shifts that indicated that Jaburetox has a low propensity to assume a stable secondary structure. (15)N relaxation studies revealed significant backbone mobility, especially in the N-terminal portion of the polypeptide. The solution structure of Jaburetox shows the presence of an α-helical motif close to the N terminus, together with two turn-like structures situated in the central portion of the protein and close to the C terminus. Similar regions were predicted as potential protein-protein interaction sites using computational tools. The knowledge of the structural properties of Jaburetox in solution is a key step to correlate its structural and biological activities.

Influence of protein-pectin electrostatic interaction on the foam stability mechanism.

This study aimed at evaluating the effect of three independent variables: biopolymer concentration (egg white proteins and pectin) (2.0-4.0%, w/w); protein:pectin ratio (15:1-55:1); and temperature (70-80 °C), at pH 3.0, using a central composite design on the foaming properties (overrun, drainage and bubble growth rate). Foams produced with protein:pectin ratio 15:1 showed the lowest bubble growth rate and the greatest drainage, whereas protein:pectin ratio 55:1 presented the lowest drainage. Complexes obtained with protein:pectin ratio 15:1 were close to electroneutrality and showed larger size (95.91 ± 8.19 µm) than those obtained with protein:pectin ratio 55:1 (45.92 ± 3.47 µm) not electrically neutral. Larger particles seemed to build an interfacial viscoelastic network at the air-water interface with reduced gas permeability, leading to greater stability concerning the disproportionation. Soluble complexes of smaller sizes increased viscosity leading to a low drainage of liquid and inhibiting the bubbles coalescence.

Sex-specific extent and severity of white matter damage in multiple sclerosis: implications for cognitive decline.

Cognitive dysfunction is common in multiple sclerosis (MS). However, the relationship between white matter (WM) damage and cognition remains insufficiently clear. This study investigates the extent and severity of WM diffusion abnormalities in MS patients and relations with cognition. Diffusion tensor imaging scans were obtained in 131 MS patients (88 women, 6 years postdiagnosis) and 49 age-matched controls (29 women). Patient groups were equal in terms of disease duration, disability, and WM lesion volume. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were compared between groups. Post hoc analyses calculated the spatial extent and severity of diffusion abnormalities to relate these to cognitive performance. In controls, 31% of WM voxels showed higher FA in men; therefore, all patient analyses were within-sex. The extent of diffusion changes was higher in male patients than in female patients for all parameters (FA: 24% in women, 53% in men), as was the severity of changes (FA: Z = -0.18 in women, Z = -0.41 in men). Especially the extent of FA abnormalities was strongly related to cognitive performance in all patients (r = -0.42, P < 0.0001). Regionally, thalamic decreases in FA were especially correlated with cognitive performance. Cognitively impaired patients showed greater extent and severity on all diffusion parameters compared to cognitively preserved patients. The WM of male patients was both more extensively and also more severely affected than that of female patients. The extent of WM FA changes, especially in the thalamus, was associated with cognitive performance in this cohort of early MS patients.

Diffusion-weighted imaging and demyelinating diseases: new aspects of an old advanced sequence.

OBJECTIVE: The purpose of this article is to discuss classic applications in diffusion-weighted imaging (DWI) in demyelinating disease and progression of DWI in the near future. CONCLUSION: DWI is an advanced technique used in the follow-up of demyelinating disease patients, focusing on the diagnosis of a new lesion before contrast enhancement. With technical advances, diffusion-tensor imaging; new postprocessing techniques, such as tract-based spatial statistics; new ways of calculating diffusion, such as kurtosis; and new applications for DWI and its spectrum are about to arise.

Subcortical atrophy and cognition: sex effects in multiple sclerosis.

OBJECTIVES: Gray matter (GM) atrophy is common in multiple sclerosis (MS), as is cognitive dysfunction. Understanding the exact relationship between atrophy and cognition requires further investigation. The aim of this study was to investigate the relationship between subcortical GM atrophy and cognition in early relapsing onset MS. METHODS: Structural MRI and neuropsychological evaluations were performed in 120 patients (80 women) and 50 controls (30 women), part of an early inception cohort, 6 years postdiagnosis. Deep GM volumes were segmented automatically. Cognition was assessed in 7 domains. Stepwise linear regression was used to predict average cognition in the patient group. RESULTS: Most deep GM volumes were reduced in patients, with larger effects on average in men (-11%) than in women (-6.3%). Only the bilateral hippocampus, amygdala, and right nucleus accumbens in men, and right hippocampus and nucleus accumbens, bilateral amygdala, and putamen in women, showed no atrophy compared to controls. All cognitive domains except visuospatial memory were affected in men; none were significantly affected in women. In the MS group, average cognition was best predicted by thalamic volume, sex, and education (adjusted R(2) = 0.31), while lesion volume was not a significant predictor in the model. CONCLUSIONS: Six years postdiagnosis, almost all subcortical structures were affected by MS, especially in men. Cognition was most severely affected in male patients. Thalamic volume, sex, and education best predicted average cognition. These results underline the relevance of specific subcortical structures to cognition, as well as the relevance of (sex-specific) atrophy in MS.

The role of demyelination in neuromyelitis optica damage: diffusion-tensor MR imaging study.

PURPOSE: To test the hypothesis that white matter damage in neuromyelitis optica (NMO) is more extensive than previously described and likely includes involvement of normal-appearing white matter and to explore by using diffusion-tensor (DT) imaging whether white matter lesions are not only related to wallerian degeneration but are also caused by demyelination. MATERIALS AND METHODS: Seventeen patients with NMO (mean age, 45 years; 14 women) were compared with 17 sex- and age-matched control subjects. The institutional review board approved the study, and all subjects gave written informed consent. In addition to conventional magnetic resonance imaging sequences, DT imaging was performed along 30 noncollinear directions by using a 1.5-T imager. For tract-based spatial statistics (TBSS) analysis, the white matter skeleton was created, and a permutation-based inference with 5000 permutations with a threshold of P less than .05 to enable the identification of abnormalities in fractional anisotropy (FA), radial diffusivity (RD), and axial diffusivity (AD) was used. Partial correlation was applied to identify whether the number of clinical relapses and disease duration were correlated with all TBSS parameters. RESULTS: TBSS showed multiple areas with significant FA decrease in patients with NMO, mainly located in the corona radiata, uncinate fasciculus, corpus callosum, optic radiation, internal and external capsules, and cerebral peduncles. The mean FA, RD, and AD in the abnormal voxels located on the corpus callosum were, respectively, 0.69 ± 0.03 (standard deviation), 0.39 × 10(23) mm(2)/sec ± 0.04, and 1.53 × 10(23) mm(2)/sec ± 0.04 in patients with NMO compared with 0.75 ± 0.02, 0.33 × 10(23) mm(2)/sec ± 0.03, and 1.57 × 10(23) mm(2)/sec ± 0.04 in control subjects (P < .0001, P < .0001, and P = .007, respectively). There was a highly significant inverse correlation between FA and RD (r = 20.976, P < .0001). CONCLUSION: The use of TBSS allowed the identification of extensive white matter damage in patients with NMO. Multiple white matter tracts were involved, including the pyramidal tract, optic radiation, and corpus callosum, likely related to both demyelination and wallerian degeneration.