Host specificity determinants as a genetic continuum

Host specificity is an important concept that underlies the interaction of all clinically and agriculturally relevant microbes with their hosts. Changes in the host specificity of animal pathogens, in particular, are often of greatest concern due to their immediate and unexpected impact on human health. Host switching or host jumps can often be traced to modification of key microbial pathogenicity factors that facilitate the formation of particular host associations. An increase in the number of genome-level studies has begun revealing that almost any type of change, from the simplest to the most complex, can potentially impact host specificity. This review highlights examples of host specificity determinants of viruses, bacteria and fungi, and presents them from within a genetic continuum that spans from the single residue through to entire genomic islands.     

Metabolic programs define dysfunctional immune responses in severe COVID-19 patients

1. Download : Download high-res image (212KB)
2. Download : Download full-size image

     

Host genetic determinants of neurological disease induced by Cas-Br-M murine leukemia virus.

Cas-Br-M is an ecotropic murine leukemia virus (MuLV) of wild-mouse origin that causes neurogenic hind-limb paralysis. By virtue of its N-tropism, the virus replicates well in tissues of mice bearing the n but not the b allele at the Fv-1 locus. To determine if different Fv-1n strains of mice were equally susceptible to virus-induced neurological disease, we inoculated NFS, C3H, DBA/2, CBA, AKR, C58, and NZB mice at birth with Cas-Br-M murine leukemia virus and observed them for the development of tremor and hind-limb paralysis. Three patterns of disease were observed: NFS and C3H mice developed disease within 3 months postinoculation; DBA/2 and CBA mice became affected between 8 and 15 months postinoculation; and no disease was observed in AKR, C58, or NZB mice up to 15 months after infection with Cas-Br-M murine leukemia virus. Studies of genetic crosses between intermediate-latency (DBA/2) or long-latency (AKR) strains with short-latency (NFS) strains showed that intermediate latency and long latency were semidominant traits determined by two or more interacting but independently assorting loci. These genes appear to determine the rate at which the virus replicates and at which viral gene products accumulate in the central nervous system.     

Metatranscriptomic analysis of host response and vaginal microbiome of patients with severe COVID-19

Science China Life Sciences -     

Host isolation and patterns of genetic variability in three populations of Teladorsagia from sheep

We have used a mitochondrial marker to explore the population genetics of an economically important parasite of sheep, Teladorsagia. We examined diversity within and between parasites from three very different host populations, as well as within and between individual hosts. One of our study populations, the Soay sheep on Hirta, St Kilda, is unusually isolated with no sheep having been introduced to the island since 1932. Worm haplotypes from Hirta were compared with those from two other host populations. Remarkably, despite its historical isolation the Hirta population shows similar levels of within-population diversity to the other study populations. No divergence between the three Teladorsagia populations was found, consistent with gene flow between the populations. The high diversity within Teladorsagia populations provides compelling evidence that this variability is a general feature of parasitic nematode populations. Such diversity may be caused by high effective population size, coupled with an increased mutation rate for mtDNA, which has important implications for the spread of anthelmintic resistance in nematode populations.     

Antibody glycosylation in COVID-19

Glycoconjugate Journal - Antibody glycosylation has received considerable attention in coronavirus disease 2019 (COVID-19) infections and recently also in vaccination. Antibody glycosylation and in...     

Host and virus determinants of picornavirus pathogenesis and tropism

The family Picornaviridae contains some notable members, including rhinovirus, which infects humans more frequently than any other virus; poliovirus, which has paralysed or killed millions over the years; and foot-and-mouth-disease virus, which led to the creation of dedicated institutes throughout the world. Despite their profound impact on human and animal health, the factors that regulate pathogenesis and tissue tropism are poorly understood. In this article, we review the clinical and economic challenges that these agents pose, summarize current knowledge of host-pathogen interactions and highlight a few of the many outstanding questions that remain to be answered.     

Causes of Hypoxemia in COVID-19

Journal of Evolutionary Biochemistry and Physiology - The global pandemic of a new coronavirus disease (COVID-19) has posed challenges to public health specialists around the world associated with...     

Stress and genetic variability

It was shown by D.K. Belyaev and the coworkers that stress can lead to changes in the degree of manifestation of genetic variation in a number of quantitative traits, such as fertility, growth rate and endocrine functions. The effects of emotional stress on the meiotic process in male mice were established. Stress inhibits both replication and repair of DNA at corresponding stages of meiosis. These are the reasons for an increase in X-Y and autosomal univalent frequency and recombination frequency in the 1-st and 2-nd chromosomes. Thus, stress leads to redistribution of recombination frequencies in the genome and produces the new spectrum of combination variation. The data presented support the concept of D.K. Belyaev that stress has substantial influence on the rate of evolution.     

Hesitancy Toward a COVID-19 Vaccine

EcoHealth - The scientific community has come together in a mass mobilization to combat the public health risks of COVID-19, including efforts to develop a vaccine. However, the success of any...     

Angiotensin converting enzyme inhibitors and angiotensin receptor blockers improved the outcome of patients with severe COVID-19 and hypertension

正Dear Editor.Hypertension was reportedly the most common coexisting condition of COVID-19 as 15%-31.2% patients with COVID-19 had hypertension,and the incidence of hypertension reached 58.3% in COVID-19 patients requiring ICU care (Wang et al.,2020).However,it remains unclear whether combined hypertension carries an increased risk for a worse outcome in patients with COVID-19 and what clinical factors independently predict death in these patients.     

Host genetic heterozygosity and age are important determinants of porcine circovirus type 2 disease prevalence in European wild boar

Emerging and zoonotic diseases are important challenges for veterinary and public health. It is therefore a key issue to assess the relative importance of various factors for disease dynamics and to understand the mechanisms behind these factors and interactions. Here, we evaluate the influence of a number of demographic and genetic factors on porcine circovirus type 2 (PCV2) antibody prevalence in the European wild boar (Sus scrofa). We measured PCV2 blood serum antibody levels of 462 randomly sampled wild boars from a cross-border area in the Netherlands and western parts of Germany in a 3-year period. These samples were also genotyped using a randomly selected genome-wide 351 SNP assay. Generalized linear mixed model analysis shows that wild boar PCV2 antibody status is determined by age and genetic heterozygosity, with an idiosyncratic influence of the year of sampling. In contrast, sex, population membership and domestic hybrid status did not significantly affect PCV2 antibody status. The observed positive relationship between PCV2 antibody status and age is most likely caused by cumulative exposure and PCV2-typical intracellular hiding behaviour. The observed positive relationship between wild boar genetic heterozygosity and PCV2 antibody status could be attributed to disappearance of relatively inbred (low-heterozygosity) individuals. This finding suggests that PCV2 can act as a selective force in wild boar populations and that disease mortality can be mediated by host heterozygosity.