scholarly journals Three hamster species with different scrapie incubation times and neuropathological features encode distinct prion proteins.

1990 ◽  
Vol 10 (3) ◽  
pp. 1153-1163 ◽  
Author(s):  
D H Lowenstein ◽  
D A Butler ◽  
D Westaway ◽  
M P McKinley ◽  
S J DeArmond ◽  
...  
Keyword(s):  
Incubation Time ◽  
Prion Proteins ◽  
Inbred Mice ◽  
Critical Role ◽  
Clinical Signs ◽  
Amino Acid Sequences ◽  
Reading Frame ◽  
Rna Analysis ◽  
Prp Gene

Given the critical role of the prion protein (PrP) in the transmission and pathogenesis of experimental scrapie, we investigated the PrP gene and its protein products in three hamster species, Chinese (CHa), Armenian (AHa), and Syrian (SHa), each of which were found to have distinctive scrapie incubation times. Passaging studies demonstrated that the host species, and not the source of scrapie prions, determined the incubation time for each species, and histochemical studies of hamsters with clinical signs of scrapie revealed characteristic patterns of neuropathology. Northern (RNA) analysis showed the size of PrP mRNA from CHa, AHa, and SHa hamsters to be 2.5, 2.4, and 2.1 kilobases, respectively. Immunoblotting demonstrated that the PrP isoforms were of similar size (33 to 35 kilodaltons); however, the monoclonal antibody 13A5 raised against SHa PrP did not react with the CHa or AHa PrP molecules. Comparison of the three predicted amino acid sequences revealed that each is distinct. Furthermore, differences within the PrP open reading frame that uniquely distinguish the three hamster species are within a hydrophilic segment of 11 amino acids that includes polymorphisms linked to scrapie incubation times in inbred mice and an inherited prion disease of humans. Single polymorphisms in this region correlate with the presence or absence of amyloid plaques for a given hamster species or mouse inbred strain. Our findings demonstrate distinctive molecular, pathological, and clinical characteristics of scrapie in three related species and are consistent with the hypothesis that molecular properties of the host PrP play a pivotal role in determining the incubation time and neuropathological features of scrapie.

Three hamster species with different scrapie incubation times and neuropathological features encode distinct prion proteins

1990 ◽  
Vol 10 (3) ◽  
pp. 1153-1163
Author(s):  
D H Lowenstein ◽  
D A Butler ◽  
D Westaway ◽  
M P McKinley ◽  
S J DeArmond ◽  
...  
Keyword(s):  
Incubation Time ◽  
Prion Proteins ◽  
Inbred Mice ◽  
Critical Role ◽  
Clinical Signs ◽  
Amino Acid Sequences ◽  
Reading Frame ◽  
Rna Analysis ◽  
Prp Gene

Given the critical role of the prion protein (PrP) in the transmission and pathogenesis of experimental scrapie, we investigated the PrP gene and its protein products in three hamster species, Chinese (CHa), Armenian (AHa), and Syrian (SHa), each of which were found to have distinctive scrapie incubation times. Passaging studies demonstrated that the host species, and not the source of scrapie prions, determined the incubation time for each species, and histochemical studies of hamsters with clinical signs of scrapie revealed characteristic patterns of neuropathology. Northern (RNA) analysis showed the size of PrP mRNA from CHa, AHa, and SHa hamsters to be 2.5, 2.4, and 2.1 kilobases, respectively. Immunoblotting demonstrated that the PrP isoforms were of similar size (33 to 35 kilodaltons); however, the monoclonal antibody 13A5 raised against SHa PrP did not react with the CHa or AHa PrP molecules. Comparison of the three predicted amino acid sequences revealed that each is distinct. Furthermore, differences within the PrP open reading frame that uniquely distinguish the three hamster species are within a hydrophilic segment of 11 amino acids that includes polymorphisms linked to scrapie incubation times in inbred mice and an inherited prion disease of humans. Single polymorphisms in this region correlate with the presence or absence of amyloid plaques for a given hamster species or mouse inbred strain. Our findings demonstrate distinctive molecular, pathological, and clinical characteristics of scrapie in three related species and are consistent with the hypothesis that molecular properties of the host PrP play a pivotal role in determining the incubation time and neuropathological features of scrapie.

scholarly journals Insights into the mysterious genetic variation profile oftprKinTreponema pallidumunder the development of natural human syphilis infection

2019 ◽  
Author(s):  
Dan Liu ◽  
Man-Li Tong ◽  
Yong Lin ◽  
Li-Li Liu ◽  
Li-Rong Lin ◽  
...  
Keyword(s):  
Amino Acid ◽  
Immune Evasion ◽  
High Frequency ◽  
Critical Role ◽  
Treponema Pallidum ◽  
Secondary Syphilis ◽  
Human Infection ◽  
Amino Acid Sequences ◽  
Potential Vaccine

AbstractAlthough the variations of thetprKgene inTreponema pallidumwere considered to play a critical role in the pathogenesis of syphilis, how actual variable characteristics oftprKin the course of natural human infection enabling the pathogen’s survive has thus far remained unclear. Here, we performed NGS to investigatetprKofT. pallidumdirectly from primary and secondary syphilis samples. Compared with diversity intprKof the strains from primary syphilis samples, there were more mixture variants found within seven V regions of thetprKgene among the strains from secondary syphilis samples, and the frequencies of predominant sequences within V regions oftprKwere generally decreased (less than 80%) with the proportion of minor variants in 10-60% increasing. Noteworthy, the variations within V regions oftprKalways obeyed a strict 3 bp changing pattern. AndtprKin the strains from the two-stage samples kept some stable amino acid sequences within V regions. Particularly, the amino acid sequences IASDGGAIKH and IASEDGSAGNLKH in V1 not only presented a high proportion of inter-population sharing, but also presented a relatively high frequency (above 80%) in the populations. Besides,tprKalways demonstrated remarkable variability in V6 at both the intra- and inter-strain levels regardless of the course. These findings unveiled that the different profile oftprK in T. pallidumdirectly from primary and secondary syphilis samples, indicating that throughout the development of syphilisT. pallidumconstantly varies its domaintprKgene to obtain the best adaptation to the host. While this changing was always subjected a strict gene conversion mechanism to keep an abnormal TprK. The highly stable peptides found in V1 would probably be promising potential vaccine components. And the highly heterogenetic regions (e.g. V6) could provide insight into the mysterious role oftprKin immune evasion.Author summaryAlthough the variations of thetprKgene inTreponema pallidumwere considered to play a critical role in the pathogenesis of syphilis, how actual variable characteristics oftprKin the course of natural human infection enabling the pathogen’s survive has thus far remained unclear. Here, we performed next-generation sequencing, a more sensitive and reliable approach, to investigatetprKofTreponema pallidumdirectly from primary and secondary syphilis patients, revealing that the profile oftprKinT. pallidumfrom the two-stage samples was different. Within the strains from secondary syphilis patients, more mixture variants within seven V regions oftprKwere found, the frequencies of their predominant sequences were generally decreased with the proportion of minor variants in 10-60% was increased. And the variations within V regions oftprKalways obeyed a strict 3 bp changing pattern. Noteworthy, the amino acid sequences IASDGGAIKH and IASEDGSAGNLKH in V1 presented a high proportion of inter-population sharing and presented a relatively high frequency in the populations. And V6 region always demonstrated remarkable variability at intra- and inter-patient levels regardless of the course. These findings provide insights into the mysterious role of TprK in immune evasion and for further exploring the potential vaccine components.

Endothelial Cells Are Essential to Sense Lipopolysaccharide in a MYD88-Dependent Manner and to Subsequently Induce Emergency Myelopoiesis

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 641-641
Author(s):  
Steffen Boettcher ◽  
Rahel Gerosa ◽  
Ramin Radpour ◽  
Markus G. Manz
Keyword(s):  
Endothelial Cells ◽  
Conflicts Of Interest ◽  
Critical Role ◽  
Hematopoietic Cells ◽  
Clinical Signs ◽  
Dependent Manner ◽  
Perivascular Cells ◽  
Hematopoietic Stem ◽  
Emergency Myelopoiesis

Abstract Abstract 641 Severe systemic infections evoke a number of characteristic clinical signs such as fever, neutrophilia and the appearance of immature myeloid precursors in the circulation (left-shift). This reflects a well-regulated hematopoietic response program to enhance myeloid cell output during times of increased hematopoietic demand, a condition which is referred to as 'emergency myelopoiesis'. Important molecular components of the emergency myelopoiesis cascade, such as cytokines and transcription factors involved, have been elucidated. However, the initial steps of emergency myelopoiesis involving pathogen recognition and translation into accelerated bone marrow (BM) myelopoiesis have only been inferred from findings on Toll-like receptor (TLR) expression on immature hematopoietic stem and progenitor cells (HSPCs) as well as on mature hematopoietic cells (e.g. macrophages). Accordingly, it has been assumed that both immature as well as mature hematopoietic cells are involved in sensing infection and inducing emergency myelopoiesis directly and indirectly, respectively. Surprisingly, by generating reciprocal BM chimeric animals mice with TLR4−/− hematopoiesis on a wild-type (WT) nonhematopoietic background (TLR4−/−→WT mice) and WT hematopoiesis on a TLR4−/− nonhematopoietic background (WT→TLR4−/−mice), we demonstrated that LPS-Induced emergency myelopoiesis depends on TLR4-expressing nonhematopoietic cells (Boettcher et al., J Immunol. 2012 Jun 15;188(12):5824–8.). However, the precise identity and localization of the nonhematopoietic cell type crucial for sensing gramnegative infection-derived lipopolysaccharide (LPS) has remained elusive to date. We now have addressed this fundamental question using BM transplantation experiments and Cre-loxP recombination technology. BM chimeric mice with a myeloid differentiation primary response gene 88 (Myd88)-deficiency in the hematopoietic lineage (MYD88−/−→WT mice) showed a normal LPS response indistinguishable to control (WT→WT) mice, while knocked out Myd88 within the nonhematopoietic compartment (WT→MYD88−/− mice) led to a non-responsiveness towards LPS similar to controls (Myd88−/−→Myd88−/− mice). These results are in line with our earlier data, thus confirming the critical role of the TLR4/MYD88 pathway in nonhematopoietic cells for the induction of emergency myelopoiesis. In order to specifically delete TLR-MyYD88-downstream signaling in various nonhematopoietic cells including BM Nestin+ mesenchymal stem cells (MSCs) and their progeny, perivascular cells, endothelial cells, and hepatocytes, we generated Nes-Cre;Myd88fl/fl, Pdgfrb-Cre;Myd88fl/fl, Tek-Cre;Myd88fl/fl, and Alb-Cre;Myd88fl/fl mice, respectively. We observed a normal increase in the frequency of BM CD11b+Gr-1low immature myeloid precursors accompanied by a decrease of BM CD11b+Gr-1high mature myeloid cells upon LPS stimulation characteristic for efficient emergency myelopoiesis in Nes-Cre;Myd88fl/fl, Pdgfrb-Cre;Myd88fl/fl, and Alb-Cre;Myd88fl/fl mice as compared to control mice. Furthermore, we measured highly-elevated plasma G-CSF levels in these mouse strains upon LPS injection. Hence, intact TLR signaling in mesenchymal stromal cells incl. Nestin+ MSCs, perivascular cells as well as hepatocytes is dispensable for induction of emergency myelopoiesis. Strikingly, Tek-Cre;Myd88fl/fl mice were completely non-responsive towards LPS stimulation as assessed by the above-mentioned parameters. Our results thus demonstrate a fundamental and unanticipated role of the endothelium for sensing of systemically spread pathogens and subsequent stimulation of BM emergency myelopoiesis. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Marked elevation in plasma osteoprotegerin constitutes an early and consistent feature of cerebral malaria

2016 ◽  
Vol 115 (04) ◽  
pp. 773-780 ◽  
Author(s):  
Kristina Gegenbauer ◽  
Jamie M. O’Sullivan ◽  
Alain Chion ◽  
Owen P. Smith ◽  
Roger J. S. Preston ◽  
...  
Keyword(s):  
Cerebral Malaria ◽  
Severe Malaria ◽  
Critical Role ◽  
Fatal Outcome ◽  
Prognostic Significance ◽  
Clinical Signs ◽  
Marked Elevation ◽  
Consistent Feature ◽  
Lactate Levels

SummaryAdherence of infected erythrocytes to vascular endothelium causes acute endothelial cell (EC) activation during Plasmodium falciparum infection. Consequently, proteins stored in Weibel-Palade (WP) bodies within EC are secreted into the plasma. Osteoprotegerin (OPG) binds to VWF and consequently is stored within WP bodies. Given the critical role of EC activation in the pathogenesis of severe malaria, we investigated plasma OPG levels in children with P. falciparum malaria. At presentation, plasma OPG levels were significantly elevated in children with cerebral malaria (CM) compared to healthy controls (means 16.0 vs 0.8 ng/ml; p<0.01). Importantly, OPG levels were also significantly higher in children with CM who had a fatal outcome, compared to children with CM who survived. Finally, in children with CM, plasma OPG levels correlated with other established prognostic indices (including plasma lactate levels and peripheral parasite density). To further investigate the relationship between severe malaria and OPG, we utilised a murine model of experimental CM in which C57BL/6J mice were infected with P. berghei ANKA. Interestingly, plasma OPG levels were increased 4.6 fold within 24 hours following P. berghei inoculation. This early marked elevation in OPG levels was observed before any objective clinical signs were apparent, and preceded the development of peripheral blood parasitaemia. As the mice became increasingly unwell, plasma OPG levels progressively increased. Collectively, these data suggest that OPG constitutes a novel biomarker with prognostic significance in patients with severe malaria. In addition, further studies are required to determine whether OPG plays a role in modulating malaria pathogenesis.

scholarly journals Ovarian gonadotrophin surge-attenuating factor (GnSAF): where are we after 20 years of research?

Reproduction ◽  
2003 ◽  
pp. 689-699 ◽  
Author(s):  
PA Fowler ◽  
T Sorsa-Leslie ◽  
W Harris ◽  
HD Mason
Keyword(s):  
Critical Role ◽  
Specific Effect ◽  
Amino Acid Sequences ◽  
Aromatase Activity ◽  
Main Role ◽  
Ovarian Granulosa Cells ◽  
Gonadotropin Surge ◽  
Lh Secretion

When gonadotrophin-stimulated IVF methods were being developed in the 1970s and 1980s, understanding of the physiology of FSH improved. In addition to its classic actions of stimulating aromatase activity and oestradiol secretion by ovarian granulosa cells, FSH was found to stimulate the ovarian production of an uncharacterized hormone known by its specific effect of reducing pituitary responsiveness to GnRH. This hormone has been called gonadotrophin surge-attenuating factor (GnSAF), gonadotropin surge-inhibiting factor (GnSIF), various abbreviations (GnSAF/IF, GnSIF/AF) and also attenuin. Although first described in the 1980s, GnSAF has still not been convincingly characterized and no published candidate amino acid sequences conclusively relate to GnSAF bioactivity. On the basis of superovulation studies and in vitro experimentation into the roles of steroids in regulating LH, GnRH and GnRH self-priming, the concept that GnSAF has a role in the regulation of LH secretion, the timing of the LH surge and the prevention of premature luteinization developed. For at least a decade, understanding of the specific GnSAF effects of reducing pituitary sensitivity to GnRH, especially GnRH self-priming and antagonizing the stimulatory effects of oestradiol on GnRH-induced LH secretion, supported this concept. However, improved knowledge of the changes in GnSAF bioactivity in follicular fluid and serum in women requires revision of this concept. The present authors propose that the main role of GnSAF is probably the negative regulation of pulsatile LH secretion, mainly during the first half of the follicular phase, indicating a critical role in the regulation of folliculogenesis and oestradiol secretion.

scholarly journals Aedes albopictus Autophagy-Related Gene 8 (AaAtg8) Is Required to Confer Anti-Bacterial Gut Immunity

2020 ◽  
Vol 21 (8) ◽  
pp. 2944
Author(s):  
Chang Eun Kim ◽  
Ki Beom Park ◽  
Hye Jin Ko ◽  
Maryam Keshavarz ◽  
Young Min Bae ◽  
...  
Keyword(s):  
Aedes Albopictus ◽  
Critical Role ◽  
Blood Feeding ◽  
Malpighian Tubules ◽  
Related Protein ◽  
Reading Frame ◽  
Interaction Sites ◽  
Microbial Infections ◽  
Gut Immunity

Autophagy is an important process by which pathogens and damaged or unused organelles are eliminated. The role of autophagy in development and the immune response to pathogens is well established. Autophagy-related protein 8 (Atg8) is involved in the formation of the autophagosome and, with the help of the serine protease Atg4, mediates the delivery of both vesicles and the autophagosome to the vacuole. Here, we cloned the Aedes albopictus autophagy-related protein 8 (AaAtg8) gene and characterized its role in the innate immunity of the mosquito against microbial infections. AaAtg8 is comprised of an open reading frame (ORF) region of 357 bp encoding a polypeptide of 118 amino acid residues. A domain analysis of AaAtg8 revealed an Atg8 ubiquitin-like domain, Atg7/Atg4 interaction sites, and peptide binding sites. The AaAtg8 mRNA expression was high in the Malpighian tubules and heads of both sugar-fed and blood-fed adult female mosquitoes. The expression level of AaAtg8 mRNA increased in the midgut and abdominal carcass following being challenged with Listeria monocytogenes. To investigate the role of AaAtg8 in the innate immune responses of Ae. albopictus, AaAtg8 gene-silenced adult mosquitoes were challenged by injection or by being fed microorganisms in blood. High mortality rates were observed in mosquitoes in which AaAtg8 was silenced after challenges of microorganisms to the host by blood feeding. This suggests that Atg8-autophagy plays a critical role in the gut immunity in Ae. albopictus.

scholarly journals Regulatory Role of Fc Receptor in mIgM+ B Lymphocyte Phagocytosis in Flounder (Paralichthys olivaceus)

2021 ◽  
Vol 12 ◽  
Author(s):  
Yanbo Hao ◽  
Xiaoqian Tang ◽  
Jing Xing ◽  
Xiuzhen Sheng ◽  
Heng Chi ◽  
...  
Keyword(s):  
B Cell ◽  
B Lymphocytes ◽  
Incubation Time ◽  
B Lymphocyte ◽  
Critical Role ◽  
Fc Receptor ◽  
Control Flow ◽  
Control Group ◽  
Cell Mediated Immunity

Fc receptor (FcR) is an important opsonin receptor on the surface of immune cells, playing an important role in antibody-dependent cell-mediated immunity. Our previous work found that the FcR of flounder showed a marked expression response in phagocytizing IgM+ B cell, which suggested that FcR might participate in regulating Ig-opsonized phagocytosis. In this paper, in order to elucidate the potential role of FcR in mediating phagocytosis of IgM+ B cell, flounder anti-E. tarda serum was prepared and complement-inactivated for the use of E. tarda opsonization, and the sera of healthy flounder were used as control. Flow cytometric analysis showed that the phagocytosis rates of antiserum-opsonized E. tarda in peripheral blood mIgM+ B lymphocytes were significantly higher than the control group, and higher phagocytosis rates of mIgM+ B lymphocyte could be detected with an increasing incubation time ranging from 1 to 5 h. The phagocytosis rates of antiserum-opsonized E. tarda by mIgM+ B lymphocyte for an incubation time of 1, 3 or 5 h were 51.1, 63.0, and 77.5% respectively, which were significantly higher than the phagocytosis rates in the control groups with 40.2, 50.9, and 63.8%, respectively. While the Fc fragment of IgM on the surface of opsonized E. tarda was blocked by rabbit anti-flounder IgM polyclonal antibodies, phagocytosis rates of mIgM+ B lymphocyte decreased significantly compared with the unblocked group. Moreover, the proportion of mIgM+ B lymphocytes with higher intracellular reactive oxygen species (ROS) levels rose to 32.1% from the control level of 23.0% after phagocytosis of antiserum-opsonized E. tarda. FcγRII and Syk were found to be significantly upregulated, while FcγRIII was significantly downregulated in the mIgM+ B lymphocytes post phagocytosis. Furthermore, when FcγRII of mIgM+ B lymphocytes was blocked by the prepared antibodies, their phagocytosis rate of antiserum-opsonized E. tarda was 39.0%, which was significantly lower than the unblocked group of 54.0%. These results demonstrate that FcR plays a critical role in mediating phagocytosis and bactericidal activity of mIgM+ B lymphocytes, which would facilitate an improved understanding of the regulatory roles of FcR in phagocytosis of teleost B lymphocytes.

scholarly journals Pairs of compensatory frameshifting mutations contribute to evolution of protein-coding sequences in vertebrates and insects

2020 ◽  
Author(s):  
Dmitry Biba ◽  
Galya Klink ◽  
Georgii Bazykin
Keyword(s):  
Negative Selection ◽  
Amino Acid Sequences ◽  
Fitness Cost ◽  
Vertebrate Species ◽  
High Confidence ◽  
Protein Coding ◽  
Coding Sequences ◽  
Reading Frame ◽  
Human Genes

AbstractInsertions and deletions of lengths not divisible by 3 in protein-coding sequences cause frameshifts that usually induce premature stop codons and may carry a high fitness cost. However, this cost can be circumvented by a second compensatory indel restoring the reading frame. The role of such compensatory frameshifting mutations (CFMs) in evolution has not been studied systematically. Here, we use whole-genome alignments of protein coding genes of 100 vertebrate species, and of 122 insect species, studying the prevalence of CFMs in their divergence. After stringent filtering, we detect a total of 11 high-confidence genes carrying pairs of CFMs, including three human genes: RAB36, ARHGAP6 and NCR3LG1. CFMs tended to occur in genes under relaxed negative selection, indicating that they are typically prevented at functionally important genes. In some instances, mutations closely predating or following the CFMs restored the biochemical similarity of the frameshifted segment to the ancestral sequence, possibly reducing or negating the fitness cost of a CFM. Typically, however, the resulting sequence bore no similarity to the ancestral one, indicating that the CFMs can uncover radically novel regions of sequence space. In total, CFMs represent a potentially important and previously overlooked source of novel variation in amino acid sequences.

The Role of the SLP in Autism Spectrum Disorder Screening and Assessment

2008 ◽  
Vol 15 (2) ◽  
pp. 50-59 ◽  
Author(s):  
Amy Philofsky
Keyword(s):  
Language Development ◽  
Critical Role ◽  
Children With Autism ◽  
Autism Spectrum ◽  
Children With Asd ◽  
Prevalence Estimates ◽  
Notable Increase ◽  
Screening Assessment ◽  
Critical Components

AbstractRecent prevalence estimates for autism have been alarming as a function of the notable increase. Speech-language pathologists play a critical role in screening, assessment and intervention for children with autism. This article reviews signs that may be indicative of autism at different stages of language development, and discusses the importance of several psychometric properties—sensitivity and specificity—in utilizing screening measures for children with autism. Critical components of assessment for children with autism are reviewed. This article concludes with examples of intervention targets for children with ASD at various levels of language development.

A critical role of iNOS-derived Nitric Oxide (NO) and progesterone in implantation

1998 ◽  
Vol 5 (1) ◽  
pp. 115A-115A
Author(s):  
K CHWALISZ ◽  
E WINTERHAGER ◽  
T THIENEL ◽  
R GARFIELD
Keyword(s):  
Nitric Oxide ◽  
Critical Role
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