Anti-streptococcal antibodies in Chinese patients with type-1 narcolepsy
SLEEP MEDICINE
Authors: Ding, Qidi; Li, Jing; Xiao, Fulong; Zhang, Chi; Dong, Xiaosong; Han, Fang
Abstract
Background: Narcolepsy type 1 (NT1) is considered to be an autoimmune disease, and streptococcal infection may be an environmental trigger. However, previous studies from Asian narcolepsy patients did not reveal elevated anti-streptolysin O [ASO]. The aim is to investigate whether large sample Chinese patients with NT1 have an increase in antistreptococcal antibody titers. Methods: A total of 214 narcolepsy patients and 360 healthy controls were recruited. All patients were DQB1*0602 positive with clear-cut cataplexy or had low CSF hypocretin-1. Participants were tested for ASO and anti DNAse B [ADB]. These patients were divided into five groups according to disease duration, including 29 patients less than 3 months; 25 from 3 months to 1 year; 40 from 1 to 3 years; 61 from 3 to 10 years and 59 patients over 10 years. Comparison was also made between children and adults with age matched controls, respectively. Results: There were no significant differences between patients and healthy controls in regard to both ASO >= 200 IU (19.2% vs. 16.9%, p = 0.50) and ADB >= 480IU (9.8% vs. 10.3%, p = 0.86). For children narcolepsy patients, ASO positive rates (19.8% vs. 18%, p = 0.68) and ADB positive rates (10.4% vs. 12%, p = 0.72) had no differences compared to age matched controls. No difference was observed in adult narcolepsy patients either, with ASO positive rates (18.5% vs. 13.8%, p = 0.39) and ADB positive rates (9.3% vs. 5.3%, p = 0.42) compared to age matched controls, respectively. ASO and ADB positive rates had no significant differences among different disease duration groups (p = 0.55 and 0.9, respectively). Conclusion: Streptococcus infection reflected by increase of ASO and ADB levels was not found in Chinese patients with type 1 narcolepsy, additional triggers for narcolepsy need to be addressed in this population. (C) 2020 Elsevier B.V. All rights reserved.
Rumen Protozoa Play a Significant Role in Fungal Predation and Plant Carbohydrate Breakdown
FRONTIERS IN MICROBIOLOGY
Authors: Williams, Cate L.; Thomas, Benjamin J.; McEwan, Neil R.; Stevens, Pauline Rees; Creevey, Christopher J.; Huws, Sharon A.
Abstract
The rumen protozoa, alongside fungi, comprise the eukaryotic portion of the rumen microbiome. Rumen protozoa may account for up to 50% of biomass, yet their role in this ecosystem remains unclear. Early experiments inferred a role in carbohydrate and protein metabolism, but due to their close association with bacteria, definitively attributing these functions to the protozoa was challenging. The advent of 'omic technologies has created opportunities to broaden our understanding of the rumen protozoa. This study aimed to utilize these methods to further our understanding of the role that protozoa play in the rumen in terms of their metabolic capacities, and in doing so, contribute valuable sequence data to reduce the chance of mis or under-representation of the rumen protozoa in meta'omic datasets. Rumen protozoa were isolated and purified using glucose-based sedimentation and differential centrifugation, extracted RNA was Poly(A) fraction enriched and DNase treated before use in a phage-based, cDNA metatranscriptomic library. Biochemical activity testing of the phage library showed 6 putatively positive plaques in response to carboxymethyl cellulose agar (indicative of cellulose activity), and no positive results for tributyrin (indicative of esterase/lipase activity) or egg yolk agar (indicative of proteolysis). Direct sequencing of the cDNA was also conducted using the Illumina HiSeq 2500. The metatranscriptome identified a wealth of carbohydrate-active enzymes which accounted for 8% of total reads. The most highly expressed carbohydrate-active enzymes were glycosyl hydrolases 5 and 11, polysaccharide lyases and deacetylases, xylanases and enzymes active against pectin, mannan and chitin; the latter likely used to digest rumen fungi which contain a chitin-rich cell membrane. Codon usage analysis of expressed genes also showed evidence of horizontal gene transfer, suggesting that many of these enzymes were acquired from the rumen bacteria in an evolutionary response to the carbohydrate-rich environment of the rumen. This study provides evidence of the significant contribution that the protozoa make to carbohydrate breakdown in the rumen, potentially using horizontally acquired genes, and highlights their predatory capacity.