Diseases caused by human T-lymphotropic virus type 1 (HTLV-1)

INTRODUCTION: Human T-lymphotropic virus type 1 (HTLV-1) belongs to the Retroviridae family (genus Deltaretrovirus ) and is directly involved in carcinogenesis. The HTLV-1 genome is represented by plus-strand RNA, which is transcribed into proviral DNA and then integrated into the genome of the host cell. After integration, HTLV-1 is present in the cells in the form of a provirus. As in the case of the human immunodeficiency virus, the main targets of HTLV-1 are CD4 + T lymphocytes. The virus is transmitted sexually, through blood transfusion, and breastfeeding by biological fluids – sperm, blood, and breast milk. The epidemiology of HTLV-1 remains a mystery: clusters of high endemicity are often located near areas where the virus is virtually absent. AIM: To analyze and discuss the clinical picture, diagnostics, and treatment of diseases caused by HTLV-1. METHODS: A literature search was conducted in the databases PubMed, eLIBRARY.ru, and cyberleninka.ru using the keywords: “HTLV-1” + “diseases”, “HTLV-1” + “diagnosis”, “HTLV-1” + “epidemiology”, “HTLV-1” + “treatment”, “HTLV-1” + “Russia” in English and Russian languages. The primary search was conducted for papers published in 2020–2024. RESULTS: HTLV-1 infection is associated with diseases such as T-cell leukemia/lymphoma and myelopathy/tropical spastic paraparesis. HTLV-1 infection causes pathologies in most organs of the human body. Because diseases associated with HTLV-1 are most often asymptomatic, etiological diagnoses are performed at the stage of pathological development or when screening donor blood for pathogens. CONCLUSION: In this review, we analyzed and discussed the clinical manifestations and course of diseases caused by HTLV-1, their diagnosis, and treatment. The lack of reliable population-based studies on the prevalence of this virus is alarming. In fact, HTLV-1 is diagnosed only in blood donors and pregnant women. Currently, this virus is considered endemic to several territories (Africa, Australia, the Middle East, Japan, etc.) and some indigenous peoples. However, we consider it important to draw the attention of both epidemiologists and clinicians to HTLV-1, given the unprecedented migration flows and international connections in the modern world

Arabidopsis thaliana phytaspase: identification and peculiar properties

Phytaspases are plant cell death-related proteases of the subtilisin-like protease family that possess an unusual aspartate cleavage specificity. Although phytaspase activity is widespread in plants, phytaspase of Arabidopsis thaliana (L.) Heynh. has escaped detection and identification thus far. Here, we show that a single gene (At4 g10540) out of 56 A. thaliana subtilisin-like protease genes encodes a phytaspase. The recombinant phytaspase was overproduced in Nicotiana benthamiana Domin leaves, isolated, and its substrate specificity and properties were characterised. At pH 5.5, at physiological mildly acidic reaction conditions, the Arabidopsis phytaspase was shown to be strictly Asp-specific. The strongly preferred cleavage motifs of the enzyme out of a panel of synthetic peptide substrates were YVAD and IETD, while the VEID-based substrate preferred by the tobacco and rice phytaspases was almost completely resistant to hydrolysis. At neutral pH, however, the Arabidopsis phytaspase could hydrolyse peptide substrates after two additional amino acid residues, His and Phe, in addition to Asp. This observation may indicate that the repertoire of Arabidopsis phytaspase targets could possibly be regulated by the conditions of the cellular environment. Similar to tobacco and rice phytaspases, the Arabidopsis enzyme was shown to accumulate in the apoplast of epidermal leaf cells. However, in stomatal cells Arabidopsis phytaspase was observed inside the cells, possibly co-localising with vacuole. Our study thus demonstrates that the Arabidopsis phytaspase possesses both important similarities with and distinctions from the already known phytaspases, and is likely to be the most divergent member of the phytaspase family

Mutations in the genome of avian influenza viruses of the H1 and H5 subtypes responsible for adaptation to mammals

Avian influenza viruses of the H1 and H5 subtypes were involved in the formation of highly pathogenic viruses that caused pandemics and panzootics in the 20th–21st centuries. In order to assess the zoonotic potential of viruses of these subtypes, two viruses of the H1N1 and H5N3 subtypes have been isolated from wild ducks in Moscow and adapted for growth in mouse lungs. Their phenotypic properties were studied, and the genetic changes that occurred during adaptation were identified. The original A/duck/Moscow/4970/2013 (H1N1) and A/duck/Moscow/4182-C/2010 (H5N3) viruses were apathogenic for mice but became pathogenic after 7–10 passages in mouse lungs. Complete genome sequencing revealed 2 amino acid substitutions in the proteins of the H1N1 mouse-adapted variant (Glu627Lys in PB2 and Asp35Asn in hemagglutinin (HA) – numbering according to H3) and 6 mutations in the proteins of H5N3 virus (Glu627lys in PB2, Val113Ala in PB1, Ser82Pro in PB1-F2, Lys52Arg in HA2, Arg65Lys in NP, and Ser-59Ile in NA). The increase in virulence is most likely due to a Glu627Lys substitution in the protein PB2 found in both viruses. The replacement Asp35Asn in HA of the mouse-adapted H1N1 virus is associated with an increase in the pH value of the HA transition to 5.5 versus 5.0 for that of the wild virus. The mutations found in the HA, NA, and PB1-F2 proteins of the adapted H5N3 variant are unique. The mutations Glu627Lys in PB2, Arg65Lys in NP, and Val113Ala in PB1 are most likely host adaptive

The neuromuscular system in flatworms: serotonin and FMRFamide immunoreactivities, and musculature in Prodistomum alaskense (Digenea: Lepocreadiidae), an endemic fish parasite of the north-western Pacific

Using the immunocytochemical method and confocal scanning laser microscopy, the pioneering data are obtained on the muscle system organization and presence and localization of biogenic amine serotonin and FMRFamide-related peptides in the nervous system of trematode Prodistomum alaskense (Ward and Fillingham, 1934) Bray and Merrett, 1998 (family Lepocreadiidae). This flatworm is an intestinal parasite of endemic representatives of marine fauna of the north-western Pacific Ocean – the prowfish, Zaprora silenus Jordan, 1896 and the lumpfish, Aptocyclus ventricosus Pallas, 1769. The article provides data of scanning electron microscopy on the tegumental topography of P. alaskense. The body wall musculature of P. alaskense has three layers of muscle fibres – the outer circular, intermediate longitudinal and inner diagonal ones. The muscle system elements are well-developed in the attachment organs, digestive and reproductive systems, in the excretory sphincter. Serotonin- and FMRFamide-immunopositive neurons and neurites are found in the head ganglia, circular commissure, longitudinal nerve cords, and in the transversal connective commissures. The innervation of the oral and ventral suckers, pharynx, and the reproductive system compartments by the serotonergic and FMRFamide-immunopositive neurites is revealed. The results are discussed in connection with the published data on the presence and functional roles of the serotonin and FMRFamide-related peptides in Platyhelminthes.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author