Glycerol phosphate (GroP)-based teichoic acids (TAs) are antigenic cell-wall components found in both enterococcus and staphylococcus species. Their immunogenicity has been explored using both... Show moreGlycerol phosphate (GroP)-based teichoic acids (TAs) are antigenic cell-wall components found in both enterococcus and staphylococcus species. Their immunogenicity has been explored using both native and synthetic structures, but no details have yet been reported on the structural basis of their interaction with antibodies. This work represents the first case study in which a monoclonal antibody, generated against a synthetic TA, was developed and employed for molecular-level binding analysis using TA microarrays, ELISA, SPR-analyses, and STD-NMR spectroscopy. Our findings show that the number and the chirality of the GroP residues are crucial for interaction and that the sugar appendage contributes to the presentation of the backbone to the binding site of the antibody. Show less
Delgadillo, J.; McMillan, D.; Gilbody, S.; Jong, K. de; Lucock, M.; Lutz, W.; ... ; Ali, S. 2021
Isolated neuroinflammatory disease has been described in case reports of familial hemophagocytic lymphohistiocytosis (FHL), but the clinical spectrum of disease manifestations, response to therapy... Show moreIsolated neuroinflammatory disease has been described in case reports of familial hemophagocytic lymphohistiocytosis (FHL), but the clinical spectrum of disease manifestations, response to therapy and prognosis remain poorly defined. We combined an international survey with a literature search to identify FHL patients with (i) initial presentation with isolated neurological symptoms; (ii) absence of cytopenia and splenomegaly at presentation; and (iii) systemic HLH features no earlier than 3 months after neurological presentation. Thirty-eight (20 unreported) patients were identified with initial diagnoses including acute demyelinating encephalopathy, leukoencephalopathy, CNS vasculitis, multiple sclerosis, and encephalitis. Median age at presentation was 6.5 years, most commonly with ataxia/gait disturbance (75%) and seizures (53%). Diffuse multifocal white matter changes (79%) and cerebellar involvement (61%) were common MRI findings. CSF cell count and protein were increased in 22/29 and 15/29 patients, respectively. Fourteen patients progressed to systemic inflammatory disease fulfilling HLH-2004 criteria at a mean of 36.9 months after initial neurological presentation. Mutations were detected inPRF1in 23 patients (61%),RAB27Ain 10 (26%),UNC13Din 3 (8%),LYSTin 1 (3%), andSTXBP2in 1 (3%) with a mean interval to diagnosis of 28.3 months. Among 19 patients who underwent HSCT, 11 neurologically improved, 4 were stable, one relapsed, and 3 died. Among 14 non-transplanted patients, only 3 improved or had stable disease, one relapsed, and 10 died. Isolated CNS-HLH is a rare and often overlooked cause of inflammatory brain disease. HLH-directed therapy followed by HSCT seems to improve survival and outcome. Show less
Ma, Y.; Li, Y.; Ali, S.; Li, P.; Zhang, W.; Rauch, M.; ... ; Wang, Y. 2019
Natural deep eutectic solvents (NADES) are proposed as alternative solvents for peroxygenase‐catalysed oxyfunctionalization reactions. Choline chloride‐based NADES are of particular interest as... Show moreNatural deep eutectic solvents (NADES) are proposed as alternative solvents for peroxygenase‐catalysed oxyfunctionalization reactions. Choline chloride‐based NADES are of particular interest as they can serve as solvent, enzyme‐stabiliser and sacrificial electron donor for the in situ H2O2 generation. This report provides the first proof‐of‐concept and basic characterisation of this new reaction system. Highly promising turnover numbers for the biocatalysts of up to 200,000 have been achieved. Show less
Delgadillo, J.; Jong, K. de; Lucock, M.; Lutz, W.; Rubel, J.; Gilbody, S.; ... ; McMillan, D. 2018
In previous publications, we described the population incidence of abnormalities in zebrafish larvae exposed to toxicants. Here, we examine the phenomenon of clustering or co-occurrence of... Show moreIn previous publications, we described the population incidence of abnormalities in zebrafish larvae exposed to toxicants. Here, we examine the phenomenon of clustering or co-occurrence of abnormalities in individual larva. Our aim is to see how this clustering can be used to assess the specificity and severity of teratogenic effect. A total of 11,214 surviving larvae, exposed continuously from 1 day postfertilization (dpf) to one of 60 toxicants, were scored at 5 dpf for the presence of eight different abnormal phenotypes. These were as follows: pericardial edema, yolk sac edema, dispersed melanocytes, bent tail, bent trunk, hypoplasia of Meckel's cartilage, hypoplasia of branchial arches, and uninflated swim bladder. For 43/60 compounds tested, there was a concentration-dependent increase in the severity score (number of different abnormalities per larva). Statistical analysis showed that abnormalities tended to cluster (i.e., to occur in the same larva) more often than expected by chance alone. Yolk sac edema and dispersed melanocytes show a relatively strong association with one another and were typically the first abnormalities to appear in single larvae as the concentration of compound was increased. By contrast, hypoplastic branchial arches and hypoplastic Meckel's cartilage were only frequently observed in the most severely affected larvae. We developed a metric of teratogenicity (TC3/8), which represents the concentration of a compound that produces, on average, 3/8 abnormalities per larva. On this basis, the most teratogenic compounds tested here are amitriptyline, chlorpromazine hydrochloride, and sodium dodecyl sulfate; the least teratogenic is ethanol. We find a strong correlation between TC3/8 and LC50 of the 43 compounds that showed teratogenic effects. When we examined the ratio of TC3/8 to LC50, benserazide hydrochloride, copper (II) nitrate trihydrate, and nicotine had the highest specific teratogenicity, while aconitine, hesperidin, and ouabain octahydrate had the lowest. We conclude that analyzing the clustering of abnormalities per larva can provide an enriched teratogenic dataset compared with simple measurement of the population frequency of abnormalities. Show less
Technological innovation has helped the zebrafish embryo gain ground as a disease model and an assay system for drug screening. Here, we review the use of zebrafish embryos and early larvae in... Show moreTechnological innovation has helped the zebrafish embryo gain ground as a disease model and an assay system for drug screening. Here, we review the use of zebrafish embryos and early larvae in applied biomedical research, using selected cases. We look at the use of zebrafish embryos as disease models, taking fetal alcohol syndrome and tuberculosis as examples. We discuss advances in imaging, in culture techniques (including microfluidics), and in drug delivery (including new techniques for the robotic injection of compounds into the egg). The use of zebrafish embryos in early stages of drug safety-screening is discussed. So too are the new behavioral assays that are being adapted from rodent research for use in zebrafish embryos, and which may become relevant in validating the effects of neuroactive compounds such as anxiolytics and antidepressants. Readouts, such as morphological screening and cardiac function, are examined. There are several drawbacks in the zebrafish model. One is its very rapid development, which means that screening with zebrafish is analogous to __screening on a run-away train.__ Therefore, we argue that zebrafish embryos need to be precisely staged when used in acute assays, so as to ensure a consistent window of developmental exposure. We believe that zebrafish embryo screens can be used in the pre-regulatory phases of drug development, although more validation studies are needed to overcome industry scepticism. Finally, the zebrafish poses no challenge to the position of rodent models: it is complementary to them, especially in early stages of drug research. Show less
Background. Enteric fever is defined by circulating Salmonella serotype Typhi or Paratyphi in the blood. The first step in developing enteric fever is internalization of salmonellae in the gut... Show moreBackground. Enteric fever is defined by circulating Salmonella serotype Typhi or Paratyphi in the blood. The first step in developing enteric fever is internalization of salmonellae in the gut epithelium. In in vitro experiments, attachment of S. Typhi to the cystic fibrosis transmembrane conductance regulator (CFTR) on the intestinal mucosa is crucial for bacterial uptake. We recently found a microsatellite polymorphism in the CFTR gene, IVS8CA, to be associated with susceptibility to enteric fever in a case-control study in Indonesia. Methods. To determine which functional variation in CFTR is associated with susceptibility to enteric fever, we sequenced all 27 exons of the CFTR gene in 25 individuals from Indonesia. Polymorphisms that occurred more than once were genotyped in the full enteric fever cohort of 116 case patients and 322 control subjects. Results. We identified 12 variants in, or adjacent to, the exons: 1 novel variant (L435V), 3 known mutations (N287K, I556V, Q1352H), and 8 known polymorphisms. Variations that occurred more than once were genotyped in the full cohort. The IVS8 TG(11)TG(12) genotype appears to provide some protection from acquiring enteric fever: having this protective genotype or a variation that is known to affect CFTR protein expression provides modest protection from enteric fever (odds ratio, 0.57; 95% confidence interval, 0.37-0.87; P < .01). Conclusions. The findings demonstrate that a correlation exists between variations in the CFTR gene and protection from enteric fever. The IVS8CA polymorphism that was identified previously may, however, be the principal functional variation causing the difference in susceptibility. Show less
In a surveillance study in Jakarta, Indonesia, 88 typhoid and 26 paratyphoid fever patients were identified by blood culture. Risk factors for transmission of typhoid fever were mainly intra... Show moreIn a surveillance study in Jakarta, Indonesia, 88 typhoid and 26 paratyphoid fever patients were identified by blood culture. Risk factors for transmission of typhoid fever were mainly intra-household factors (poor hand-washing hygiene, recent household contacts), whereas paratyphoid was mainly contracted through street food. In an additional study, street vendors observed poorer hand-washing and food-handling hygiene compared to food handlers in restaurants, and had higher bacterial loads in dishwater. Further host factor-studies in (para)typhoid patients revealed that polymorphisms in genes encoding pro-inflammatory cytokines (IFN-_, IL1A/B, IL1R1, TNFRSF1A, CASP1 and CRP) were not associated with susceptibility to typhoid fever, and might therefore at most be associated with severity of disease. An association was found of typhoid fever and a polymorphism in the PARK2/PACRG proteasome-mediated protein degradation pathway through ubiquitination, similar to infection with Mycobacterium leprae. Also an association between genotypes in the Cystic Fibrosis Transmembrane Conductance Regulator (the affected protein in Cystic Fibrosis) and susceptibility to typhoid fever was found, suggesting a decreased adherence potential of S. typhi to intestinal mucosal cells with these polymorphisms. Finally, bacterial characteristics were compared by use of AFLP and biochemical/antibiotic susceptibility profiles, showing very homogeneous S. typhi and S. paratyphi A strains circulating in the study area. Show less
