Роль экологических факторов в распространении эймерий

Gregarines are single-celled parasites in the phylum Apicomplexa that infect invertebrates. They are highly abundant on three levels: among a large diversity of invertebrates, in the proportion of population of organisms they infect, and within individually infected organisms. Because of their remarkable prevalence, we hypothesize that they play an important role in support of their hosts. However, studies done to date on the impact of gregarines on their host are conflicting. Therefore, we studied the impact of gregarines on their host using a model Gregarina niphandrodes infection in Tenebrio molitor. The impact of infection was measured by comparing beetles with no or low infection to those with artificially induced high infection. The numbers of individuals in each of the three easily visible developmental stages of the T. molitor (larva, pupa, and adult) were censused weekly. From these observations, fertilities and probabilities of survival with transition between stages were estimated. These estimated vital rates were used to construct a stage-classified projection matrix model. We also measured the longevity of individual beetles with low and high infection that were grown in isolation. The results indicate that there is no significant difference in the population dynamics of beetles with low and high infection. However, the longevity was significantly different between beetles with low infection than the deliberately highly infected group.

ObjectiveAdult primary human hepatocytes (PHHs) support the complete infection cycle of natural HCV from patients’ sera. The molecular details underlying sera infectivity towards these cells remain largely unknown. Therefore, we...

Sorghum is an important food, feed, and industrial crop worldwide. Parasitic weeds of the genus Striga constitute a major constraint to sorghum production, particularly in the drier parts of the world. In this study we analysed the Striga germination stimulants, strigolactones, in the root exudates of 36 sorghum genotypes and assessed Striga germination and infection. Low germination-stimulating activity and low Striga infection correlated with the exudation of low amounts of 5-deoxystrigol and high amounts of orobanchol, whereas susceptibility to Striga and high germination-stimulating activity correlated with high concentrations of 5-deoxystrigol and low concentrations of orobanchol. Marker analysis suggested that similar genetics to those previously described for the resistant sorghum variety SRN39 and the susceptible variety Shanqui Red underlie these differences. This study shows that the strigolactone profile in the root exudate of sorghum has a large impact on the level of Striga infection. High concentrations of 5-deoxystrigol result in high infection, while high concentrations of orobanchol result in low infection. This knowledge should help to optimize the use of low germination stimulant-based resistance to Striga by the selection of sorghum genotypes with strigolactone profiles that favour normal growth and development, but reduce the risk of Striga infection.

SUMMARY Recovery and specific infectivity of infectious RNA from cowpea chlorotic mottle virus of low specific infectivity (14 to 21 day infections) were greatly improved by using antioxidants during virus purification and RNA extraction, and by disrupting coat protein with pronase before phenol-SDS extraction. Total infectivity of RNA from virus of low infectivity was increased over 30 times. RNA profiles obtained using polyacrylamide gels were then similar for virus with high (4 to 7 day infections) or low specific infectivity. Low specific infectivity, therefore, seems to be caused by alteration of the coat protein or of the protein-RNA interaction in intact virus particles.

Activation of influenza A viruses by trypsin treatment

BackgroundPrevious studies have demonstrated that DC differentially regulate influenza A virus (IAV)–specific CD8 T cell responses in vivo during high and low dose IAV infections. Furthermore, in vitro infection of DC with IAV at low versus high multiplicities of infection (MOI) results in altered cytokine production and a reduced ability to prime naïve CD8 T cell responses. Flow cytometric detection of IAV proteins within DC, a commonly used method for detection of cellular IAV infection, does not distinguish between the direct infection of these cells or their uptake of viral proteins from dying epithelial cells.Methods/Principal FindingsWe have developed a novel, sensitive, single-cell RT-PCR–based approach to assess the infection of respiratory DC (rDC) and lymph node (LN)-resident DC (LNDC) following high and low dose IAV infections. Our results show that, while a fraction of both rDC and LNDC contain viral mRNA following IAV infection, there is little correlation between the percentage of rDC containing viral mRNA and the initial IAV inoculum dose. Instead, increasing IAV inoculums correlate with augmented rDC MOI.Conclusion/SignificanceTogether, our results demonstrate a novel and sensitive method for the detection of direct IAV infection at the single-cell level and suggest that the previously described ability of DC to differentially regulate IAV-specific T cell responses during high and low dose IAV infections could relate to the MOI of rDC within the LN rather than the percentage of rDC infected.

615: Syphilis immunoassay signal-to-cutoff ratio helps obstetricians determine maternal infectivity in RPR- women using reverse algorithm

SARS-CoV-2 continues to accumulate mutations to evade immunity, leading to breakthrough infections after vaccination. How researchers can anticipate the evolutionary trajectory of the virus in advance in the design of next-generation vaccines requires investigation. Here, we performed a comprehensive study of 11,650,487 SARS-CoV-2 sequences, which revealed that the SARS-CoV-2 spike (S) protein evolved not randomly but into directional paths of either high infectivity plus low immune resistance or low infectivity plus high immune resistance. The viral infectivity and immune resistance of variants are generally incompatible, except for limited variants such as Beta and Kappa. The Omicron variant has the highest immune resistance but showed high infectivity in only one of the tested cell lines. To provide cross-clade immunity against variants that undergo diverse evolutionary pathways, we designed a new pan-vaccine antigen (Span). Span was designed by analyzing the homology of 2675 SARS-CoV-2 S protein sequences from the NCBI database before the Delta variant emerged. The refined Span protein harbors high-frequency residues at given positions that reflect cross-clade generality in sequence evolution. Compared with a prototype wild-type (Swt) vaccine, which, when administered to mice, induced serum with decreased neutralization activity against emerging variants, Span vaccination of mice elicited broad immunity to a wide range of variants, including those that emerged after our design. Moreover, vaccinating mice with a heterologous Span booster conferred complete protection against lethal infection with the Omicron variant. Our results highlight the importance and feasibility of a universal vaccine to fight against SARS-CoV-2 antigenic drift.

BackgroundHepatitis C virus (HCV) encodes two transmembrane glycoproteins E1 and E2 which form a heterodimer. E1 is believed to mediate fusion while E2 has been shown to bind cellular receptors. It is clear that HCV uses a multi-receptor complex to gain entry into susceptible cells, however key elements of this complex remain elusive. In this study, the role of a highly conserved RGE/RGD motif of HCV E2 glycoprotein in viral entry was examined. The effect of each substitution mutation in this motif was tested by challenging susceptible cell lines with mutant HCV E1E2 pseudotyped viruses generated using a lentiviral system (HCVpp). In addition to assaying infectivity, producer cell expression and HCVpp incorporation of HCV E2 proteins, CD81 binding profiles, and conformation of mutants were examined.ResultsBased on these characteristics, mutants either displayed wt characteristics (high infectivity [≥ 90% of wt HCVpp], CD81 binding, E1E2 expression, and incorporation into viral particles and proper conformation) or very low infectivity (≤ 20% of wt HCVpp). Only amino acid substitutions of the 3rd position (D or E) resulted in wt characteristics as long as the negative charge was maintained or a neutral alanine was introduced. A change in charge to a positive lysine, disrupted HCVpp infectivity at this position.ConclusionAlthough most amino acid substitutions within this conserved motif displayed greatly reduced HCVpp infectivity, they retained soluble CD81 binding, proper E2 conformation, and incorporation into HCVpp. Our results suggest that although RGE/D is a well-defined integrin binding motif, in this case the role of these three hyperconserved amino acids does not appear to be integrin binding. As the extent of conservation of this region extends well beyond these three amino acids, we speculate that this region may play an important role in the structure of HCV E2 or in mediating the interaction with other factor(s) during viral entry.

This study examined factors related to high fear of coronavirus disease 2019 (COVID-19) infection in healthcare workers (HCWs) in COVID-19 dedicated teams. We assigned 371 HCWs to low, medium, and high COVID-19 infection fear groups, and investigated factors associated with COVID-19 infection fear. High COVID-19 infection fear was significantly associated with being a woman and poor professional quality of life. High COVID-19 infection fear group had higher burnout levels and secondary traumatic stress scores than the low and medium fear groups. These findings deepen our understanding of risk factors for and psychological outcomes of COVID-19 infection fear in HCWs.

Objective To investigate the related risk factors for hospital-acquired lower respiratory infection in patients with hematologic malignancies after chemotherapy. Methods The 287 patients with hematologic malignancies from April 2011 to October 2013 were selected as the subjects, the clinical data and related laboratory tests were collected, the risk factors for hospital-acquired lower respiratory infection were analyzed though the single factor and multi-factor Logistic regression analysis. Results Among the 287 cases, 47 cases showed lower respiratory infection, the incidence of infection was 18.6%; multiple myeloma had the highest infection rate, the infection rate was 24.1%, the proportion of infections in patients with acute myelogenous leukemia was the most larges, accounting for 40.4% of all infections; 59 strains of pathogenic bacteria were isolated from the 47 cases including gram-negative (G-) bacilli, gram positive (G+ ) cocci, fungus, accounting for 57.6%, 28.8% and 13.5% respectively. Klebsiella pneumoniae, e. coli and staphylococcus aureus were the most common three pathogens. Multi-factor classification Logistic regression analysis showed that age (OR=1.683), smoking index (OR=3.217), serum albumin (OR=2.764), granulocyte absolute value (OR=4.525), the ECOG score (OR=3.136), QOL score (OR=2.875), preventive use of antibiotics (OR=1.864), hospitalization stays (OR=3.871) were high risk factors for hospital-acquired lower respiratory infection in patients after chemotherapy. Conclusions A variety of mixed high factors can lead to hospital-acquired lower respiratory infection in patients with hematologic malignancies after chemotherapy, measures of infection control should be strengthen to control all kinds of risk factors, in order to reduce the incidence of patients with lower respiratory tract infection. Key words: Hematologic malignancies; Lower respiratory tract infection; Risk factor; Hospital infection

Language delay in severely neglected children: A cumulative or specific effect of risk factors?

Tall fescue ( Festuca arundinacea Schreb.) is an important cool‐season perennial forage used for grazing animals in the humid regions of the USA and throughout the world. The fungal endophyte Neotyphodium coenophialum Glenn, Bacon, & Hanlin naturally inhabits the majority of tall fescue stands producing a variety of alkaloids in leaf tissue that can cause animal health disorders on ingestion. We hypothesized that endophyte infection would modify the stock and activity of various soil C and N pools (total, particulate, microbial biomass, and mineralizable), but that fertilization (13.4–1.5–5.6 vs. 33.6–3.7–13.9 g N–P–K m −2 yr −1 ) and cultivar (‘Kentucky‐31’, K‐31; ‘AU‐Triumph’; and ‘Johnstone’) might alter these responses. Soil organic C and total N at a depth of 0 to 20 cm under K‐31 with high fertilization were greater with high (4197 g C m −2 and 266 g N m −2 ) than with low (3872 g C m −2 and 242 g N m −2 ) endophyte infection at the end of 20 yr. Under low fertilization, soil organic C and total N were not different between low and high endophyte infection. Differences in C and N pools among cultivars with low fertilization were as large as among K‐31 fertilization‐endophyte comparisons, but appeared to be related to factors other than endophyte infection frequency. Carbon and N contents of small macroaggregates (0.25–1.0 mm) were the only soil properties that were related ( r = 0.70, P = 0.001) to endophyte infection frequency (range of 1–79%) across all treatments. Soil C and N pools can be modified by endophyte infection, but these results narrowed this phenomenon to (i) conditions of higher fertility and (ii) predominantly in small macroaggregates.

Four Hundred (400) samples of Chrysichthys nigrodigitatus were examined for Henneguya chrysichthys using methods described for gills examination and haemopatholgy. 135 (33.8%), Chrysichthys nigrodigitatus were infected by Henneguya chrysichthys. The infection was seen on the gill filament as an oval cyst somewhat white and visible to the naked eyes. 27 (20%), 88 (65.2%) and 20 (14.8%) were recorded for low, moderate and high infection respectively. Lowest (22.7%) and highest (45.5%) prevalence were observed in the months of December and May respectively. Prevalence was higher in wet season (54.1%) than in dry season (45.9,%) More female fish (51.1%) had infection than the male fish (48.8%).Haematological examination revealed changes in blood cell count, erythrocyte sedimentary rate and Haematocrit counts. Hemoglobin (per 100mI) remains the same in infected and uninfected fish. Erythrccyte count (X106/mm3) was 1.28�1.11 and 1.0�0.53 while leucocytes count (per mm3) was 2.36�1.0 and 43200�0.60 foruninfected and infected fish respectively. Leucocytosis in infected fish was marked by lymphocytes (35.11�0.32), Neutrophils (26.32�1.65), plasmocytes (23.06�0.9 1) and monocytes (16.0�0.21). Corresponding values of these classes of Leucocytes are 7.38�0.69, 21,86 � 1.71, 6.90� 1.12 and 7.24� 1.09 respectively in uninfected fish. Infected fish appeared weak and emaciated.

The N-linked Glycan g15 within the V3 Loop of the HIV-1 External Glycoprotein gp120 Affects Coreceptor Usage, Cellular Tropism, and Neutralization