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Here, the authors develop a mouse model of Loa loa that reflects human infections, including eosinophilia, and determine effects of ivermectin treatment.

Basic and translational research on loiasis, a filarial nematode infection of medical importance, is impeded by a lack of suitable Loa loa infection models and techniques of obtaining and culturing life cycle stages. We describe the development of a new method for routine production of infective third-stage larvae (L3) of L. loa from the natural intermediate arthropod vector host, Chrysops silacea, following experimental infection with purified microfilariae. At 14-days post-infection of C. silacea, the fly survival rate was 43%. Survival was significantly higher in flies injected with 50 mf (55.2%) than those that received 100 mf (31.0%). However, yield per surviving fly and total yield of L3 was markedly higher in the group of flies inoculated with 100 mf (3474 vs 2462 L3 produced). The abdominal segment hosted the highest percentage recovery of L3 (47.7%) followed by head (34.5%) and thorax (17.9%). L. loa larval survival was higher than 90% after 30 days of in vitro culture. The in vitro moulting success rate to the L4 larval stage was 59.1%. After experimental infection of RAG2-/-IL-2γc-/-mice, the average L. loa juvenile adult worm recovery rate was 10.5% at 62 dpi. More than 87% of the worms were recovered from the muscles and subcutaneous tissues. Worms recovered measured an average 24.3 mm and 11.4 mm in length for females (n = 5) and males (n = 5), respectively. In conclusion, L. loa mf injected into C. silacea intrathoracically develop into infective larvae that remain viable and infective comparable to L3 obtained through natural feeding on the human host. This technique further advances the development of a full laboratory life cycle of L. loa where mf derived from experimentally-infected animals may be utilized to passage life cycle generations via intrathoracic injections of wild-caught vector hosts.

The Onchocerca ochengi adult implant and Brugia malayi microfilariemic Severe-Combined Immunodeficient (SCID) mouse models are validated screens to measure macrofilaricidal and microfilaricidal activities of candidate onchocerciasis drugs. The purpose of this study was to assess whether 5 daily sub-cutaneous (s.c.) injections of standard flubendazole (FBZ) suspension (10mg/kg), a single s.c. injection (10mg/kg) or 5 daily repeated oral doses of FBZ amorphous solid dispersion (ASD) formulation (0.2, 1.5 or 15mg/kg) mediated macrofilaricidal efficacy against O. ochengi male worms implanted into SCID mice. The direct microfilaricidal activity against circulating B. malayi microfilariae of single dose FBZ ASD formulation (2 or 40 mg/kg) was also evaluated and compared against the standard microfilaricide, ivermectin (IVM). Systemic exposures of FBZ/FBZ metabolites achieved following dosing were measured by pharmacokinetic (PK) bioanalysis. At necropsy, five weeks following start of FBZ SC injections, there were significant reductions in burdens of motile O. ochengi worms following multiple injections (93%) or single injection (82%). Further, significant proportions of mice dosed following multiple injections (5/6; 83%) or single injection (6/10; 60%) were infection negative (drug-cured). In comparison, no significant reduction in recovery of motile adult O. ochengi adult worms was obtained in any multiple-oral dosage group. Single oral-dosed FBZ did not mediate any significant microfilaricidal activity against circulating B. malayi mf at 2 or 7 days compared with >80% efficacy of single dose IVM. In conclusion, multiple oral FBZ formulation doses, whilst achieving substantial bioavailability, do not emulate the efficacy delivered by the parenteral route in vivo against adult O. ochengi. PK analysis determined FBZ efficacy was related to sustained systemic drug levels rather than achievable Cmax. PK modelling predicted that oral FBZ would have to be given at low dose for up to 5 weeks in the mouse model to achieve a matching efficacious exposure profile.

ABSTRACT Many fungal adhesins have short, β-aggregation-prone sequences that play important functional roles, and in the Candida albicans adhesin Als5p, these sequences cluster the adhesins after exposure to shear force. Here, we report that Saccharomyces cerevisiae flocculins Flo11p and Flo1p have similar β-aggregation-prone sequences and are similarly stimulated by shear force, despite being nonhomologous. Shear from vortex mixing induced the formation of small flocs in cells expressing either adhesin. After the addition of Ca2+, yeast cells from vortex-sheared populations showed greatly enhanced flocculation and displayed more pronounced thioflavin-bright surface nanodomains. At high concentrations, amyloidophilic dyes inhibited Flo1p- and Flo11p-mediated agar invasion and the shear-induced increase in flocculation. Consistent with these results, atomic force microscopy of Flo11p showed successive force-distance peaks characteristic of sequentially unfolding tandem repeat domains, like Flo1p and Als5p. Flo11p-expressing cells bound together through homophilic interactions with adhesion forces of up to 700 pN and rupture lengths of up to 600 nm. These results are consistent with the potentiation of yeast flocculation by shear-induced formation of high-avidity domains of clustered adhesins at the cell surface, similar to the activation of Candida albicans adhesin Als5p. Thus, yeast adhesins from three independent gene families use similar force-dependent interactions to drive cell adhesion. IMPORTANCE The Saccharomyces cerevisiae flocculins mediate the formation of cellular aggregates and biofilm-like mats, useful in clearing yeast from fermentations. An important property of fungal adhesion proteins, including flocculins, is the ability to form catch bonds, i.e., bonds that strengthen under tension. This strengthening is based, at least in part, on increased avidity of binding due to clustering of adhesins in cell surface nanodomains. This clustering depends on amyloid-like β-aggregation of short amino acid sequences in the adhesins. In Candida albicans adhesin Als5, shear stress from vortex mixing can unfold part of the protein to expose aggregation-prone sequences, and then adhesins aggregate into nanodomains. We therefore tested whether shear stress from mixing can increase flocculation activity by potentiating similar protein remodeling and aggregation in the flocculins. The results demonstrate the applicability of the Als adhesin model and provide a rational framework for the enhancement or inhibition of flocculation in industrial applications.

ABSTRACT There is increasing evidence that many amyloids in living cells have physiological functions. On the surfaces of fungal cells, amyloid core sequences in adhesins can aggregate into 100- to 1,000-nm-wide patches to form high-avidity adhesion nanodomains on the cell surface. The nanodomains form through interactions that have amyloid-like properties: binding of amyloid dyes, perturbation by antiamyloid agents, and interaction with homologous sequences. To test whether these functional interactions are mediated by typical amyloid interactions, we substituted an amyloid core sequence, LVFFA, from human Aβ protein for the native sequence IVIVA in the 1,419-residue Candida albicans adhesin Als5p. The chimeric protein formed cell surface nanodomains and mediated cellular aggregation. The native sequence and chimeric adhesins responded similarly to the amyloid dye thioflavin T and to amyloid perturbants. However, unlike the native protein, the nanodomains formed by the chimeric protein were not force activated and formed less-robust aggregates under flow. These results showed the similarity of amyloid interactions in the amyloid core sequences of native Als5p and Aβ, but they also highlighted emergent properties of the native sequence. Also, a peptide composed of the Aβ amyloid sequence flanked by amino acids from the adhesin formed two-dimensional sheets with sizes similar to the cell surface patches of the adhesins. These results inform an initial model for the structure of fungal cell surface amyloid nanodomains. IMPORTANCE Protein amyloid aggregates are markers of neurodegenerative diseases such as Alzheimer’s and Parkinsonism. Nevertheless, there are also functional amyloids, including biofilm-associated amyloids in bacteria and fungi. In fungi, glycoprotein adhesins aggregate into cell surface patches through amyloid-like interactions, and the adhesin clustering strengthens cell-cell binding. These fungal surface amyloid nanodomains mediate biofilm persistence under flow, and they also moderate host inflammatory responses in fungal infections. To determine whether the amyloid-like properties of fungal surface nanodomains are sequence specific, we ask whether a disease-associated amyloid core sequence has properties equivalent to those of the native sequence in a fungal adhesin. A chimeric adhesin with an amyloid sequence from the Alzheimer’s disease protein Aβ instead of its native sequence effectively clustered the adhesins on the cell surface, but it showed a different response to hydrodynamic shear. These results begin an analysis of the sequence dependence for newly discovered activities for fungal surface amyloid nanodomains.

Candida albicans adhesins have amyloid-forming sequences. In Als5p, these amyloid sequences cluster cell surface adhesins to create high avidity surface adhesion nanodomains. Such nanodomains form after force is applied to the cell surface by atomic force microscopy or laminar flow. Here we report centrifuging and resuspending S. cerevisiae cells expressing Als5p led to 1.7-fold increase in initial rate of adhesion to ligand coated beads. Furthermore, mechanical stress from vortex-mixing of Als5p cells or C. albicans cells also induced additional formation of amyloid nanodomains and consequent activation of adhesion. Vortex-mixing for 60 seconds increased the initial rate of adhesion 1.6-fold. The effects of vortex-mixing were replicated in heat-killed cells as well. Activation was accompanied by increases in thioflavin T cell surface fluorescence measured by flow cytometry or by confocal microscopy. There was no adhesion activation in cells expressing amyloid-impaired Als5pV326N or in cells incubated with inhibitory concentrations of anti-amyloid dyes. Together these results demonstrated the activation of cell surface amyloid nanodomains in yeast expressing Als adhesins, and further delineate the forces that can activate adhesion in vivo. Consequently there is quantitative support for the hypothesis that amyloid forming adhesins act as both force sensors and effectors.

Abstract The use of herbal products for the treatment of malaria, has increased globally. However, inadequate scientific studies about the safety and effectiveness of such herbal products have been raised. Also, the reduced sensitivity of the malaria parasites to artemisinin-based combination therapies is of concern. There is therefore the need for new antimalarial medications including those from alternative sources such as herbal medicinal products. In this study, a prospective, comparative parallel group randomized, clinical study was done to assess the safety and effectiveness of Mist Amen Fevermix and Mist Edhec Malacure with Artemether/Lumefantrine as control at the Tafo Government Hospital, Kumasi between July and November 2019, after Committee on Human Research, Publication and Ethics approval (CHRPE/AP/424/19). The study was conducted in accordance with Good Clinical and Laboratory Practice (GCLP) and registered with the Pan African Clinical Trials Registry with trial number PACTR202109664146698. Participant completed an informed consent form. Randomization was based on a single sequence to allocate participants to a group. SPSS version 19. One-way ANOVA test and exploratory statistics was used for data analysis. Total sample size was 150 participants with 50 on each arm of the group. Male and female patients aged 15–45 years and meet inclusion criteria with clinically established malaria were treated with Mist Amen Fevermix and Mist Edhec Malacure, at the specified doses of 45 mls (0.1063 g) and 30 mls (0.0521 g) three times daily after meals for three days. Artemether/Lumefantrine was administered at a dose of 80/480 mg/kg twice daily after meals for three days. Baseline data was taken on day 0. Patients were then followed up on Day 3, 7 and 28 to establish treatment outcomes and any side effect using a checklist for signs and symptoms and Karnofsky’s scale to assess the quality of life. Mist Amen Fevermix was effective with a cure rate of 95.89%. Mist Edhec Malacure was also effective with a cure rate of 91.87%. The cure rate of Artemether/Lumefantrine was 97.25%. Kidney and liver panels were within normal reference range at the end of the 28-day study. This study supports the use of Mist Amen Fevermix and Mist Edhec Malacure, two multi-component products as safe and effective for the treatment of uncomplicated malaria. Both products achieved a comparable clinical treatment outcome with Artemether/Lumefantrine.

There is an upsurge in the incidence of persons living with infectious diseases and their associated symptoms. Also, there is increased resistance and high cost of available synthetic antimicrobial therapeutic agents. This calls for screening candidate herbal products to examine the risk-to-benefit ratio for users. Moreover, there are inadequate proven scientific studies to assess the quality, effectiveness, and toxicity of herbal products that traditional medicine practitioners in Ghana commonly use for the management of infectious diseases such as those caused by Neisseria gonorrhoeae, Candida albicans and the symptomatic management of symptoms associated with infections like cough, skin infections among others and gastritis. Kantinka BA and Kantinka Herbaltics, two multicomponent herbal products, have been used to manage the above-mentioned disease conditions. The study aims to evaluate the in vitro antibacterial activity, assess the retrospective clinical effectiveness (clinical responses; the disappearance of presenting signs and symptoms associated with infections, gastritis), and the quality and toxicity of Kantinka BA and Kantinka Herbaltics. The products are registered by the Food and Drugs Authority (FDA). Data on 200 patients who were diagnosed with infectious diseases such as Human Immunodeficiency Virus (HIV) / Acquired Immunodeficiency Syndrome (AIDS) and associated symptoms from January 2018 to June 2018 was obtained from the Adom Herbal Clinic, and the Tafo Government Herbal Medicine Records Unit was assessed. The antibacterial activity of the products was evaluated using the HT-SPOTi method. Phytochemical screening, microbial load, and pH were carried out according to standard procedures. Acute toxicity was carried out according to the Organization for Economic Cooperation and Development (OECD) guideline 425. Phytochemical screening, pH, and microbial load have been established for both products. Binding toxicity studies revealed that the products are non-toxic at a 2000 mg/kg dose. The two products exhibited antimicrobial activities against the test organisms with Minimum Inhibitory Concentration (MIC) and Minimum Lethal Concentration (MLC) determined for Kantinka BA and Kantinka Herbaltics as 5% and 10% and

The author offers an experiment that develops an equation for the period of a mass rotating in a vertical circle with string tension at the top of the circle as zero. Calculus- and algebra-based models, comparing experimental and theoretical results, and the method for determining speed at the bottom of the circle are discussed.