Transmission Stages Research Articles

Mussel memory: can bivalves learn to fear parasites?

Fear plays a crucial role in predator–prey interactions and can have cascading impacts on the structure of whole ecosystems. Comparable fear effects have recently been described for hosts and their parasites but our understanding of the underlying mechanisms remains limited by the lack of empirical examples. Here, we experimentally tested if bivalves Mytilus edulis can potentially ‘learn to fear’ the infective transmission stages (cercariae) of the trematode Himasthla elongata, and if experienced mussels change their parasite-avoidance behaviour accordingly. Our results show that previous experience with parasites, but not established infections, lead to a reduced filtration activity in mussels in the presence of cercariae compared to parasite-naive conspecifics. This reduction in filtration activity resulted in lower infection rates in mussels. Since parasite avoidance comes at the cost of lower feeding rates, mussels likely benefit from the ability to adjust their defence behaviour when infection risks are high. Overall, these dynamic processes of avoidance behaviour can be expected to play a significant role in regulating the bivalves' ecosystem engineering function in coastal habitats.

Ensuring the effectiveness and safety of peripheral blockades

Adequate analgesia determines the success of the performed surgical intervention. In modern surgery, most of postoperative complications are directly related to ineffective therapy of pain syndrome in the perioperative period. The main principle of modern analgesia is its multicomponence, when analgesia, neurovegetative blockade and relaxation are achieved and potentiated by different drugs and methods. The blockade of nociceptive impulses with a local anesthetic at the transmission stage provides effective, targeted analgesia, hyporefl exia and muscle relaxation, prevents the sensitization of neuroaxial structures, hyperalgesia and the development of postoperative chronic pain syndrome. At the same time, providing analgesia with drugs of central action leads to the ineffectiveness of therapy in 80 % of cases, which has serious consequences.The aim. According to the literature review, to evaluate the effectiveness and safety of peripheral blockades on the example of performing a blockade of the pterygopalatine ganglion.Conclusion. The pterygopalatine blockade has broad indications for use in ophthalmology, which is explained by the complex structure of the pterygopalatine ganglion and the possibility of simultaneous infl uence on sympathetic, parasympathetic and nociceptive innervation. All the presented methods of pterygopalatine blockade performance have their advantages and disadvantages. Ultrasound navigation eliminates technical difficulties and the possibility of damage of the pterygopalatine fossa anatomical structures, ensuring the effectiveness and safety of the pterygopalatine blockade.

Statement on the Use of Untreated Manure Containing Raw Sewage

The Norwegian department of agriculture decided to re-evaluate the Regulation No. 951 of 4 July 2003 on fertilizers and soil improvers of organic origin. The Norwegian Food Safety Authority (NFSA) requested VKM for a statement on the use of manure from farms where grey water and human waste (sewage) is disposed of directly to the farm manure cellar.
 Consideration was given to differences in risk according to the types of domestic wastewater, the species of animal from which the manure derived, the extent and type of sanitary facilities, the crops to which the amended manure is applied, and the effects of storage on infection risk.
 According to current legislation, sewage sludge cannot be spread on land where vegetables, potatoes, berries or fruit are grown. Furthermore, sewage cannot be spread on meadows or used for horticultural purposes. In private gardens, parks, playgrounds and similar residential areas, sewage may be used only as a component in a fertiliser, and not applied at the surface. Use of sewage as a fertilizer for the cultivation of grains is permitted. Sewage can also be used when establishing vegetation along roads and embankments.
 VKM concludes that manure cellars, to which wastewater, from private household use, and sewage from toilets in the outbuildings are drained, may contain pathogens from humans, in addition to those pathogens originating from animals. The quantity and species of pathogens in this sewage-amended manure would reflect the species and prevalence of pathogens in the population using the facilities. Although the prevalence of intestinal pathogens in the Norwegian human population is relatively low, it should be noted that farms in Norway often provide tourist accommodation, camping facilities, and may house migrant short-term employees during the summer season during which labour requirements are increased. Thus non-Norwegian populations may also use toilet facilities on these farms, and thus when considering the risk of human pathogens, consideration should also be given to people from countries where the prevalence of such pathogens may be higher.
 As many viruses and parasites are host-specific, the risk of contamination of produce with human pathogens from such manure is likely to be greater than from manure which has not been amended with untreated sewage.
 Pathogen survival is affected by storage, but it should be noted that some pathogens have robust and environmentally resistant transmission stages (e.g. parasite oocysts, cysts and eggs), a proportion of which may survive for prolonged periods in stored manure.

The Chronicle of John of Nikiu: Its Arabic Vorlage and Its Afterlife in Ethiopia

Abstract The Chronicle of John of Nikiu is an important historiographical text which was most probably composed in Coptic but only survives in its Ethiopic translation, executed from an Arabic intermediate version. Although none of the witnesses to the earlier stages of the text transmission has been found so far, the Ethiopic version offers some material which allows for speculations on the possible text transformation in the course of time. The impact of the Chronicle on the literary production of Ethiopia documents a peculiar process of text reception.

Rapid Androgen-Responsive Proteome Is Involved in Prostate Cancer Progression.

Androgen exerts its functions by binding with an androgen receptor (AR). It can activate many signaling pathways that are important to the progression of castration-resistant prostate cancer (CRPC). Here, we characterized the rapid proteomic changes seen at 5, 15, 30, and 60 min after the androgen treatment of VCaP cells via the tandem mass tag (TMT) labeling strategy. A total of 5529 proteins were successfully identified and quantified. Dynamic time profiling of protein expression patterns allowed us to identify five protein clusters involved in various stages of androgen-initiated signal transmission and processing. More details of protein functions and localization patterns, and our elucidation of an AR-interacting protein network, were obtained. Finally, we validated the expression level of AR-regulated proteins known to be significantly regulated in CRPC patients using the mouse xenograft model and patient samples. Our work offers a systematic analysis of the rapid proteomic changes induced by androgen and provides a global view of the molecular mechanisms underlying CRPC progression.

Transneuronal Degeneration in the Visual Pathway of Rats following Acute Retinal Ischemia/Reperfusion.

The maintenance of visual function not only requires the normal structure and function of neurons but also depends on the effective signal propagation of synapses in visual pathways. Synapses emerge alterations of plasticity in the early stages of neuronal damage and affect signal transmission, which leads to transneuronal degeneration. In the present study, rat model of acute retinal ischemia/reperfusion (RI/R) was established to observe the morphological changes of neuronal soma and synapses in the inner plexiform layer (IPL), outer plexiform layer (OPL), and dorsal lateral geniculate nucleus (dLGN) after retinal injury. We found transneuronal degeneration in the visual pathways following RI/R concretely presented as edema and mitochondrial hyperplasia of neuronal soma in retina, demyelination, and heterotypic protein clusters of axons in LGN. Meanwhile, small immature synapses formed, and there are asynchronous changes between pre- and postsynaptic components in synapses. This evidence demonstrated that transneuronal degeneration exists in RI/R injury, which may be one of the key reasons for the progressive deterioration of visual function after the injury is removed.

Stressed Out About Plasmodium falciparum Gametocytogenesis.

Blocking malaria transmission is critical to malaria control programs but remains a major challenge especially in endemic regions with high levels of asymptomatic infections. New strategies targeting the transmissible sexual stages of the parasite, called gametocytes, are needed. This review focuses on P. falciparum gametocytogenesis in vivo and in vitro. Highlighting advances made elucidating genes required for gametocyte production and identifying key questions that remain unanswered such as the factors and regulatory mechanisms that contribute to gametocyte induction, and the mechanism of sequestration. Tools available to begin to address these issues are also described to facilitate advances in our understanding of this important stage of the life cycle.

HIV-1-RNA and total HIV-1-DNA loads in the genital compartment in men receiving dolutegravir- versus darunavir-based combined ART (cART) regimens during primary HIV infection.

Dolutegravir is a widespread integrase strand-transfer inhibitor (INSTI) recommended for treatment of primary HIV infection (PHI). PHI is a high-risk stage for sexual transmission because of the high viral load in semen. Yet dolutegravir concentrations in semen are lower than in blood during chronic treatment. To compare the kinetics of HIV-RNA and total HIV-DNA in the genital compartment in subjects receiving either tenofovir/emtricitabine/dolutegravir or tenofovir/emtricitabine/darunavir/cobicistat as a first-line combined ART (cART) at the time of PHI. Eighteen subjects receiving tenofovir/emtricitabine/dolutegravir and 19 receiving tenofovir/emtricitabine/darunavir/cobicistat enrolled in the ANRS169 OPTIPRIM-2 trial participated in the genital substudy. Between week (W) 0 and W2 HIV-RNA in seminal plasma (SP) decreased by 1 log10 copies/mL. Undetectable SP HIV-RNA was achieved in similar proportions between the two regimens at each timepoint. Overall, eight patients still presented detectable HIV-RNA or HIV-DNA in semen at W48; 15.4% and 28.6% presented detectable HIV-RNA and 9.1% and 14.3% presented detectable HIV-DNA in dolutegravir- and darunavir-based cART groups, respectively, with no significant difference. For the first time, to the best of our knowledge, we showed that a dolutegravir-based regimen initiated as soon as PHI reduces HIV-RNA and HIV-DNA with no difference compared with a control group receiving a darunavir-based regimen. Although the viral purge in semen seems longer after treatment in PHI than CHI, due to high viral loads, early dolutegravir-based treatment initiation permits a major decay of both viral particles and infected cells in semen, efficiently reducing the high risk of transmission during PHI.

Single-cell transcriptomics reveals hidden information in trypanosomatids

Dixenic parasites often encounter environmental extremes during the transition from vector to host. Preadapted transmission stages overcome these challenges to promote parasites' survival and ensure life cycle progression. Recently, Vigneron et al. and Briggs et al. used single-cell transcriptomics to investigate developmental stage specific gene expression patterns during parasite differentiation.

Understanding the Secret of SARS-CoV-2 Variants of Concern/Interest and Immune Escape.

The global pandemic of the coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), places a heavy burden on global public health. Four SARS-CoV-2 variants of concern including B.1.1.7, B.1.351, B.1.617.2, and P.1, and two variants of interest including C.37 and B.1.621 have been reported to have potential immune escape, and one or more mutations endow them with worrisome epidemiologic, immunologic, or pathogenic characteristics. This review introduces the latest research progress on SARS-CoV-2 variants of interest and concern, key mutation sites, and their effects on virus infectivity, mortality, and immune escape. Moreover, we compared the effects of various clinical SARS-CoV-2 vaccines and convalescent sera on epidemic variants, and evaluated the neutralizing capability of several antibodies on epidemic variants. In the end, SARS-CoV-2 evolution strategies in different transmission stages, the impact of different vaccination strategies on SARS-CoV-2 immune escape, antibody therapy strategies and COVID-19 epidemic control prospects are discussed. This review will provide a systematic and comprehensive understanding of the secret of SARS-CoV-2 variants of interest/concern and immune escape.

A perspective on SARS-CoV-2 and community transmission in the top COVID-19 affected nations

In most countries, during the initial months of the COVID-19 outbreak resources were directed to mitigation measures that prevented severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission from symptomatic individuals. The coverage of the pre-symptomatic and asymptomatic individuals’ testing required intensive clinical sampling along with rigorous symptom-based screening. Based on the SARS-CoV-2 transmission, the disease outbreak across nations was divided into four distinct stages: (i) epidemic, (ii) community transmission, (iii) local transmission, and (iv) imported cases. Here we discuss the COVID-19 community transmission stage for the top ten COVID-19 affected nations. Epidemic dynamics and policies implemented to contain the spread of SARS-CoV-2 infection varied globally. Further, the mitigation strategies and related health policies for dealing with the pandemic were based on the stages of transmission of the disease. We suggest that correctly identifying the transmission stage during a pandemic ensures the implementation of mitigation strategies. Thus prompt analysis of the status of COVID-19 transmission stage(s) in any nation seems crucial to direct health policies accordingly.

Analysis of Measures to Reduce the Energy Facilities Impact on the Environment on the Example of the Crimean Energy System

The world community is seriously concerned about the harmful effects of human activity on the environment. Reducing this influence is on the agenda for most countries. Energy facilities play the greatest role in environmental pollution with harmful emissions. Reducing the generated electricity will positively contribute to an improvement of the environmental situation. This can be achieved by decreasing electric energy losses during its transmission. The paper considers losses at various stages of electric energy transmission, presents the components of actual losses, as well as measures to reduce them. The effectiveness of two methods is analyzed on the example of the Crimean energy system: the method of interrupting the low voltage network and the method of disconnecting part of the transformers in the low loads mode. Conclusions about the need for operational regulation of the considered energy system in order to reduce electric energy losses are made.

Metabolism of 8-aminoquinoline (8AQ) primaquine via aromatic hydroxylation step mediated by cytochrome P450 enzyme using density functional theory

The 8-aminoquinoline (8AQ) drug Primaquine (PQ) is a prime anti-malarial drug, used in the treatment of malaria due to plasmodium vivax and plasmodium ovale. The hydroxylated metabolite of Primaquine is also responsible for many essential sexual transmission stages of Plasmodium falciparum. Present work reported the hydroxylation of Primaquine at ortho (2PQ) and para (4PQ) position by Cytochrome P450 enzyme. Density functional theory (DFT) is used to investigate the underlying pathway for aromatic hydroxylation at ortho (2PQ) and para (4PQ) position to produce 2-hydroxylated and 4-hydroxylated Primaquine respectively. Truncated model of putative active oxidant i.e. ferryl oxo porphyrin cation radical [FeIV(O)(heme+·)], which is referred as Cpd I in Cytochrome P450 enzymes has been used to mimic the behavior of enzyme. Substrate was modelled and reaction mechanism for two degenerate spin states namely doublet and quartet were performed to dwell the overall potential energy landscape, along with electronic structure and properties of reactant complex (RC), transition states (TS), intermediates (IM) and product complex (PC). The reaction was stepwise with electrophillic addition as the rate determining step, spin selectivity product formation was observed for hydroxylated product formation on high spin (HS) surface. All calculations are done for isolated reaction coordinate.

Modelling infectious diseases with herd immunity in a randomly mixed population

The conventional susceptible-infectious-recovered (SIR) model tends to magnify the transmission dynamics of infectious diseases, and thus the estimated total infections and immunized population may be higher than the threshold required for infection control and eradication. The study developed a new SIR framework that allows the transmission rate of infectious diseases to decline along with the reduced risk of contact infection to overcome the limitations of the conventional SIR model. Two new SIR models were formulated to mimic the declining transmission rate of infectious diseases at different stages of transmission. Model A utilized the declining transmission rate along with the reduced risk of contact infection following infection, while Model B incorporated the declining transmission rate following recovery. Both new models and the conventional SIR model were then used to simulate an infectious disease with a basic reproduction number (r0) of 3.0 and a herd immunity threshold (HIT) of 0.667 with and without vaccination. Outcomes of simulations were assessed at the time when the total immunized population reached the level predicted by the HIT, and at the end of simulations. Further, all three models were used to simulate the transmission dynamics of seasonal influenza in the United States and disease burdens were projected and compared with estimates from the Centers for Disease Control and Prevention. For the simulated infectious disease, in the initial phase of the outbreak, all three models performed expectedly when the sizes of infectious and recovered populations were relatively small. As the infectious population increased, the conventional SIR model appeared to overestimate the infections even when the HIT was achieved in all scenarios with and without vaccination. For the same scenario, Model A appeared to attain the level predicted by the HIT and in comparison, Model B projected the infectious disease to be controlled at the level predicted by the HIT only at high vaccination rates. For infectious diseases with high r0, and at low vaccination rates, the level at which the infectious disease was controlled cannot be accurately predicted by the current theorem. Transmission dynamics of infectious diseases with herd immunity can be accurately modelled by allowing the transmission rate of infectious diseases to decline along with the reduction of contact infection risk after recovery or vaccination. Model B provides a credible framework for modelling infectious diseases with herd immunity in a randomly mixed population.

A Novel Methodology for Optimal SVC Location Considering N-1 Contingencies and Reactive Power Flows Reconfiguration

In this research, an alternative methodology is proposed for the location of Static VAR Compensators (SVC) in power systems, considering the reconfiguration of reactive power flows through the optimal switching of the transmission stage, which resembles the contingency restriction N-1 usually considered in transmission expansion planning. Based on this methodology, the contingency index was determined, which made it possible to determine which is the contingency that generates the greatest voltage degradation in the system. For the quantification of reactive flows, optimal AC power flows were used, which minimize the operating costs of the power system subject to transmission line switching restrictions, line charge-ability, voltages and node angles. To determine the node in which the compensation should be placed, the contingency index criterion was used, verifying the voltage profile in the nodes. The proposed methodology was tested in the IEEE test systems of 9, 14 nodes and large-scale systems of 200, 500 and 2000 bus-bars; to verify that the proposed methodology is adequate, the stability of the EPS was verified. Finally, the model allows satisfactorily to determine the node in which the SVC is implemented and its compensation value.

Sexual Development in Non-Human Parasitic Apicomplexa: Just Biology or Targets for Control?

Simple SummaryCellular reproduction is a key part of the apicomplexan life cycle, and both mitotic (asexual) and meiotic (sexual) cell divisions produce new individual cells. Sexual reproduction in most eukaryotic taxa indicates that it has had considerable success during evolution, and it must confer profound benefits, considering its significant costs. The phylum Apicomplexa consists of almost exclusively parasitic single-celled eukaryotic organisms that can affect a wide host range of animals from invertebrates to mammals. Their development is characterized by complex steps in which asexual and sexual replication alternate and the fertilization of a macrogamete by a microgamete results in the formation of a zygote that undergoes meiosis, thus forming a new generation of asexual stages. In apicomplexans, sex is assumed to be induced by the (stressful) condition of having to leave the host, and either gametes or zygotes (or stages arising from it) are transmitted to a new host. Therefore, sex and meiosis are linked to parasite transmission, and consequently dissemination, which are key to the parasitic lifestyle. We hypothesize that improved knowledge of the sexual biology of the Apicomplexa will be essential to design and implement effective transmission-blocking strategies for the control of the major parasites of this group.The phylum Apicomplexa is a major group of protozoan parasites including gregarines, coccidia, haemogregarines, haemosporidia and piroplasms, with more than 6000 named species. Three of these subgroups, the coccidia, hemosporidia, and piroplasms, contain parasites that cause important diseases of humans and animals worldwide. All of them have complex life cycles involving a switch between asexual and sexual reproduction, which is key to their development. Fertilization (i.e., fusion of female and male cells) results in the formation of a zygote that undergoes meiosis, forming a new generation of asexual stages. In eukaryotes, sexual reproduction is the predominant mode of recombination and segregation of DNA. Sex is well documented in many protist groups, and together with meiosis, is frequently linked with transmission to new hosts. Apicomplexan sexual stages constitute a bottleneck in the life cycle of these parasites, as they are obligatory for the development of new transmissible stages. Consequently, the sexual stages represent attractive targets for vaccination. Detailed understanding of apicomplexan sexual biology will pave the way for the design and implementation of effective transmission-blocking strategies for parasite control. This article reviews the current knowledge on the sexual development of Apicomplexa and the progress in transmission-blocking vaccines for their control, their advantages and limitations and outstanding questions for the future.

The evolution and governance of online rumors during the public health emergency: taking COVID-19 pandemic related rumors as an example

ABSTRACT The outbreak of the infodemic during COVID-19 caused mass panic in society. Studying the evolution law of online rumors in the relatively complete cycle of COVID-19 can improve the pertinence of rumor governance. In this paper, the Python crawler program was used to collect rumor-refuting microblogs. Based on the development of public opinion and the pandemic, it was divided into five stages, including incubation stage, explosion stage, digestion stage, fluctuation stage, and re-digestion stage. Then, the statistical analysis methods ranging from correlation analysis to chi-square analysis and analytical methods like hot trend analysis, stage-based analyses of quantity, hot words and subjects were used to study the dynamic evolution laws of online rumors from the perspective of quantity and content. The research found that online rumors had the rules of periodic evolution of quantity and periodic fluctuation of hot words and subjects, which were in line with the COVID-19 pandemic. Social platforms such as WeChat and Tik Tok were the main places for rumors’ generation and propagation. In different stages of rumor transmission, the public mood was staggered repeatedly, and the homogeneous or same rumors would spread repeatedly. Based on the above laws, the corresponding governance strategies were put forward.

Molluscicides against the snail-intermediate host of Schistosoma: a review.

Schistosomiasis, a neglected tropical disease (NTD), is one of the most prevalent parasitoses in the World. Certain freshwater snail species are the intermediate host in the life cycle of schistosome species. Controlling snails employing molluscicides is an effective, quick, and convenient intervention strategy to prevent the spread of Schistosoma species in endemic regions. Advances have been made in developing both synthetic molluscicides and molluscicides derived from plants. However, at present, the development of molluscicides is not adapted to the actual demand for snails and schistosoma controlling. We undertake a systematic review of exploitation and application of synthetic molluscicides and molluscicides derived from plants to combat intermediate host snails. The detailed molluscicidal activity, structure–activity relationship, structural feature, and possible mechanism of some molluscicides are also highlighted, which may afford an important reference for the design of new, more effective molluscicides with low environmental impact and realize the aim of controlling schistosome at transmission stages.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00436-021-07288-4.

Complete genome sequencing and molecular characterization of SARS-COV-2 from COVID-19 cases in Alborz province in Iran

Iran was among countries which was hard hit at the early stage of the coronavirus disease 2019 (COVID-19) pandemic and dealt with the second wave of the pandemic in May and June 2020; however, there are a very limited number of complete genome sequences of acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from Iran. In this study, complete genome sequences of the virus in the samples obtained from three patients in Alborz province in May and June 2020 were generated and analyzed using bioinformatic methods. The sequenced genomes were positioned in a cluster with B.4 lineage along with the sequences from other countries namely, United Arab Emirates and Oman. There were seven single nucleotide variations (SNVs) in common in all samples and only one of the sequenced genomes showed the D614G amino acid substitution. Three SNVs, 1397 G > A, 28688T > C, 29742 G > T, which had already been reported in February, were found with high frequency in all the sequenced genomes in this study, implying that viral diversity reflected in the early stages of viral transmission in Iran were established in the second wave. Considering the importance of molecular epidemiology in response to ongoing pandemic, there is an urgent need for more complete genome sequencing and comprehensive analyses to gain insight into the transmission, adaptation and evolution of the virus in Iran.

АВТОМАТИЧЕСКИЕ ТРАНСМИССИИ. КОМПЛЕКС АЛГОРИТМОВ ТЕХНОЛОГИИ «CLUTCH-TO-CLUTCH SHIFTS»: АНАЛИЗ АРХИТЕКТУРЫ, ОБОБЩЕННАЯ СТРУКТУРА, РАЗВИТИЕ. ЧАСТЬ 2

The article continues the series of the author publications, which considers the main provisions of the “Clutch-to-Clutch Shifts” (CTC) technology — technology for automatic controlling the switching of automatic transmission (AT) stages, used in the global mass production of vehicles, hybrid and battery electric vehicles. It provides high-quality shifts, brought to the level of continuously variable transmissions. Development of power units in recent years has led to a rapid increase in the number of AT stages, which is accompanied by a complication of kinematic schemes, designs, control algorithms and, in general, an increase in the role of mechatronic control systems (MCS) in ensuring their high technical level. Effectiveness of the CTC technology depends on the perfection of the algorithms used. But their composition is not specified, which, with a large amount of information, makes it difficult for potential users to navigate in this set. In this paper, we propose (for the first time in the Russian language) the generalized structure of a set of standard algorithms necessary for the implementation of this technology in the AT MCS, which is developed on the basis of their selection from a pre-formed database of patents and publications on the theory and technology of AT control, following classification and grouping by functional purpose. For each item of the structure, there are links to patents with matching names. Detailed descriptions of several typical CTC algorithms in the AT MCS of General Motors patents are given.