Protecting Free-Living Dormice: Molecular Identification of Cestode Parasites in Captive Dormice (Muscardinus avellanarius) Destined for Reintroduction

The success of any population translocation programme relies heavily on the measures implemented to control and monitor the spread of disease. Without these measures, programmes run the risk of releasing immunologically naïve species or, more dangerously, introducing novel infectious agents to native populations. As a precaution, a reintroduction programme for the common or hazel dormouse, Muscardinus avellanarius, in England screens dormice before release following captive breeding. Using PCR sequencing of a range of genes, we tested whether the same species of tapeworm(s) were present in captive and free-living dormice. Whilst only Rodentolepis straminea were identified in free-living dormice, cestode ova found in a captive individual produced a molecular match closely related to Hymenolepis microstoma and a previously unrecorded Rodentolepis species. To prevent putting at risk the free-living population, we recommended the continued treatment of dormice showing tapeworm infection before release. Our work demonstrates how molecular techniques can be used to inform reintroduction programmes, reduce risk from disease and increase chances of reintroduction success

Rheological study of the chitosan/glutaraldehyde chemical gel system

©1998. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This document is the Accepted, version of a Published Work that appeared in final form in Polymer Gels and Networks . To access the final edited and published work see https://doi.org/10.1016/S0966-7822(98)00032-XChitosan dissolved in 0.1 mol l~1 acetic acid shows an apparent yield stress at very low frequencies, probably due to a structuring process yielding gel-like response. It re#ects complex relaxation mechanisms once chains disentangle and relax, presumably due to incipient hydrophobic contacts reinforced by the relative sti!ness of the chitosan chains, which tend to slow down reptation. When chemical cross-linkages are introduced, the weak self-associated network of chitosan is gradually replaced by a permanent covalent network as the molar ratio of aldehyde/amine groups, R, is increased. At R"0.4 a glass-to-rubber-type transition is observed, while at R"0.5 the form of the mechanical spectrum suggests the co-existence of a chemically cross-linked gel &dissolved' in a second entangled network formed by chitosan chains of restricted mobility. At higher cross-linking levels (R'1) a strong permanent gel is formed. The observed frequency dependence near the rheological gel point suggests several modes of relaxation processes

Physicochemical properties and cell viability of shrimp chitosan films as affected by film casting solvents. I-potential use as wound dressing

: Chitosan solubility in aqueous organic acids has been widely investigated. However, most of the previous works have been done with plasticized chitosan films and using acetic acid as the film casting solvent. In addition, the properties of these films varied among studies, since they are influenced by different factors such as the chitin source used to produce chitosan, the processing variables involved in the conversion of chitin into chitosan, chitosan properties, types of acids used to dissolve chitosan, types and amounts of plasticizers and the film preparation method. Therefore, this work aimed to prepare chitosan films by the solvent casting method, using chitosan derived from Litopenaeus vannamei shrimp shell waste, and five different organic acids (acetic, lactic, maleic, tartaric, and citric acids) without plasticizer, in order to evaluate the effect of organic acid type and chitosan source on physicochemical properties, degradation and cytotoxicity of these chitosan films. The goal was to select the best suited casting solvent to develop wound dressing from shrimp chitosan films. Shrimp chitosan films were analyzed in terms of their qualitative assessment, thickness, water vapor permeability (WVP), water vapor transmission rate (WVTR), wettability, tensile properties, degradation in phosphate buffered saline (PBS) and cytotoxicity towards human fibroblasts using the resazurin reduction method. Regardless of the acid type employed in film preparation, all films were transparent and slightly yellowish, presented homogeneous surfaces, and the thickness was compatible with the epidermis thickness. However, only the ones prepared with maleic acid presented adequate characteristics of WVP, WVTR, wettability, degradability, cytotoxicity and good tensile properties for future application as a wound dressing material. The findings of this study contributed not only to select the best suited casting solvent to develop chitosan films for wound dressing but also to normalize a solubilization protocol for chitosan, derived from Litopenaeus vannamei shrimp shell waste, which can be used in the pharmaceutical industry.info:eu-repo/semantics/publishedVersio

Next-Generation Probiotics Targeting \u3ci\u3eClostridium difficile\u3c/i\u3e through Precursor- Directed Antimicrobial Biosynthesis

Integration of antibiotic and probiotic therapy has the potential to lessen the public health burden of antimicrobial-associated diseases. Clostridium difficile infection (CDI) represents an important example where the rational design of next-generation probiotics is being actively pursued to prevent disease recurrence. Because intrinsic resistance to clinically relevant antibiotics used to treat CDI (vancomycin, metronidazole, and fidaxomicin) is a desired trait in such probiotic species, we screened several bacteria and identified Lactobacillus reuteri to be a promising candidate for adjunct therapy. Human-derived L. reuteri bacteria convert glycerol to the broad-spectrum antimicrobial compound reuterin. When supplemented with glycerol, strains carrying the pocR gene locus were potent reuterin producers, with L. reuteri 17938 inhibiting C. difficile growth at a level on par with the level of growth inhibition by vancomycin. Targeted pocR mutations and complementation studies identified reuterin to be the precursor-induced antimicrobial agent. Pathophysiological relevance was demonstrated when the codelivery of L. reuteri with glycerol was effective against C. difficile colonization in complex human fecal microbial communities, whereas treatment with either glycerol or L. reuteri alone was ineffective. A global unbiased microbiome and metabolomics analysis independently confirmed that glycerol precursor delivery with L. reuteri elicited changes in the composition and function of the human microbial community that preferentially targets C. difficile outgrowth and toxicity, a finding consistent with glycerol fermentation and reuterin production. Antimicrobial resistance has thus been successfully exploited in the natural design of human microbiome evasion of C. difficile, and this method may provide a prototypic precursor-directed probiotic approach. Antibiotic resistance and substrate bioavailability may therefore represent critical new determinants of probiotic efficacy in clinical trials

Application of reverse vaccinology for the identification of epitope candidates from Rickettsia rickettsii

643-647Rocky mountain spotted fever is a severe disease caused by Rickettsia rickettsii that frequently causes the death of the patients. As there are not effective vaccines for this disease, we employed reverse vaccinology to find epitope candidates useful for vaccine development. To apply this bioinformatics, we used the following online software: ProPred1, RANKPEP, and HLA binding, to evaluate 143 amino acid sequences in the genome of Rickettsia rickettsii (NC_009882 Sheila Smith). This strategy allowed us to identify 19 epitope sequences with affinity to HLA I alleles: A0201, A24; HLA-B: B3501, B3901

Application of reverse vaccinology for the identification of epitope candidates from Rickettsia rickettsii

Rocky mountain spotted fever is a severe disease caused by Rickettsia rickettsii that frequently causes the death of the patients. As there are not effective vaccines for this disease, we employed reverse vaccinology to find epitope candidates useful for vaccine development. To apply this bioinformatics, we used the following online software: ProPred1, RANKPEP, and HLA binding, to evaluate 143 amino acid sequences in the genome of Rickettsia rickettsii (NC_009882 Sheila Smith). This strategy allowed us to identify 19 epitope sequences with affinity to HLA I alleles: A0201, A24; HLA-B: B3501, B3901

Mass spectrometry imaging identifies palmitoylcarnitine as an immunological mediator during Salmonella Typhimurium infection

Salmonella Typhimurium causes a self-limiting gastroenteritis that may lead to systemic disease. Bacteria invade the small intestine, crossing the intestinal epithelium from where they are transported to the mesenteric lymph nodes (MLNs) within migrating immune cells. MLNs are an important site at which the innate and adaptive immune responses converge but their architecture and function is severely disrupted during S. Typhimurium infection. To further understand host-pathogen interactions at this site, we used mass spectrometry imaging (MSI) to analyse MLN tissue from a murine model of S. Typhimurium infection. A molecule, identified as palmitoylcarnitine (PalC), was of particular interest due to its high abundance at loci of S. Typhimurium infection and MLN disruption. High levels of PalC localised to sites within the MLNs where B and T cells were absent and where the perimeter of CD169+ sub capsular sinus macrophages was disrupted. MLN cells cultured ex vivo and treated with PalC had reduced CD4+CD25+ T cells and an increased number of B220+CD19+ B cells. The reduction in CD4+CD25+ T cells was likely due to apoptosis driven by increased caspase-3/7 activity. These data indicate that PalC significantly alters the host response in the MLNs, acting as a decisive factor in infection outcome

Study of the Thermal Phase Transition of Poly(N,N-diethylacrylamide-co-N-ethylacrylamide) Random Copolymers in Aqueous Solution

N-alkyl-substituted polyacrylamides exhibit a thermal coil-to-globule transition in aqueous solution driven by an increase in hydrophobic interactions with rising temperature. With the aim of understanding the role of N-alkyl substituents in the thermal transition, this study focuses on the molecular interactions underlying the phase transition of poly(N,N-diethylacrylamide-co-N-ethylacrylamide) random copolymers. Poly(N,N-diethylacrylamide) (PDEAm), poly(N-ethylacrylamide) (PNEAm), and their random copolymers were synthesized by free radical polymerization and their chemical structure characterized spectroscopically. It was found that the values of the cloud-point temperature increased with PNEAm content, and particle aggregation processes took place, increasing the negative charge density on their surface. The cloud-point temperature of each copolymer decreased with respect to the theoretical values calculated assuming an absence of interactions. It is attributed to the formation of intra- and interchain hydrogen bonding in aqueous solutions. These interactions favor the formation of more hydrophobic macromolecular segments, thereby promoting the cooperative nature of the transition. These results definitively reveal the dominant mechanism occurring during the phase transition in the aqueous solutions of these copolymers

Rickettsia typhi IN RODENTS AND R. felis IN FLEAS IN YUCATÁN AS A POSSIBLE CAUSAL AGENT OF UNDEFINED FEBRILE CASES

Rickettsia typhi is the causal agent of murine typhus; a worldwide zoonotic and vector-borne infectious disease, commonly associated with the presence of domestic and wild rodents. Human cases of murine typhus in the state of Yucatán are frequent. However, there is no evidence of the presence of Rickettsia typhi in mammals or vectors in Yucatán. The presence of Rickettsia in rodents and their ectoparasites was evaluated in a small municipality of Yucatán using the conventional polymerase chain reaction technique and sequencing. The study only identified the presence of Rickettsia typhi in blood samples obtained from Rattus rattus and it reported, for the first time, the presence of R. felis in the flea Polygenis odiosus collected from Ototylomys phyllotis rodent. Additionally, Rickettsia felis was detected in the ectoparasite Ctenocephalides felis fleas parasitizing the wild rodent Peromyscus yucatanicus. This study’s results contributed to a better knowledge of Rickettsia epidemiology in Yucatán