scholarly journals The LORF5 Gene Is Non-essential for Replication but Important for Duck Plague Virus Cell-to-Cell Spread Efficiently in Host Cells

2021 ◽  
Vol 12 ◽  
Author(s):  
Bingjie Shen ◽  
Yunjiao Li ◽  
Anchun Cheng ◽  
Mingshu Wang ◽  
Ying Wu ◽  
...  
Keyword(s):  
Life Cycle ◽  
Virulent Strain ◽  
Artificial Chromosome ◽  
Host Cells ◽  
Specific Gene ◽  
High Morbidity ◽  
Functional Studies ◽  
Duck Plague Virus ◽  
Recombination System

Duck plague virus (DPV) can cause high morbidity and mortality in many waterfowl species within the order Anseriformes. The DPV genome contains 78 open reading frames (ORFs), among which the LORF2, LORF3, LORF4, LORF5, and SORF3 genes are unique genes of avian herpesvirus. In this study, to investigate the role of this unique LORF5 gene in DPV proliferation, we generated a recombinant virus that lacks the LORF5 gene by a two-step red recombination system, which cloned the DPV Chinese virulent strain (DPV CHv) genome into a bacterial artificial chromosome (DPV CHv-BAC); the proliferation law of LORF5-deleted mutant virus on DEF cells and the effect of LORF5 gene on the life cycle stages of DPV compared with the parent strain were tested. Our data revealed that the LORF5 gene contributes to the cell-to-cell transmission of DPV but is not relevant to virus invasion, replication, assembly, and release formation. Taken together, this study sheds light on the role of the avian herpesvirus-specific gene LORF5 in the DPV proliferation life cycle. These findings lay the foundation for in-depth functional studies of the LORF5 gene in DPV or other avian herpesviruses.

scholarly journals Lysosomal Fusion Is Essential for the Retention of Trypanosoma cruzi Inside Host Cells

2004 ◽  
Vol 200 (9) ◽  
pp. 1135-1143 ◽  
Author(s):  
Luciana O. Andrade ◽  
Norma W. Andrews
Keyword(s):  
Plasma Membrane ◽  
Life Cycle ◽  
Trypanosoma Cruzi ◽  
Parasitophorous Vacuole ◽  
Cell Types ◽  
Significant Fraction ◽  
Host Cells ◽  
Productive Infection ◽  
Kinase Inhibition

Trypomastigotes, the highly motile infective forms of Trypanosoma cruzi, are capable of infecting several cell types. Invasion occurs either by direct recruitment and fusion of lysosomes at the plasma membrane, or through invagination of the plasma membrane followed by intracellular fusion with lysosomes. The lysosome-like parasitophorous vacuole is subsequently disrupted, releasing the parasites for replication in the cytosol. The role of this early residence within lysosomes in the intracellular cycle of T. cruzi has remained unclear. For several other cytosolic pathogens, survival inside host cells depends on an early escape from phagosomes before lysosomal fusion. Here, we show that when lysosome-mediated T. cruzi invasion is blocked through phosophoinositide 3-kinase inhibition, a significant fraction of the internalized parasites are not subsequently retained inside host cells for a productive infection. A direct correlation was observed between the lysosomal fusion rates after invasion and the intracellular retention of trypomastigotes. Thus, formation of a parasitophorous vacuole with lysosomal properties is essential for preventing these highly motile parasites from exiting host cells and for allowing completion of the intracellular life cycle.

scholarly journals A glance on anti-viral strategy target Coronavirus life cycle

2020 ◽  
Vol 9 (1) ◽  
pp. 1-22
Author(s):  
Yue Zhang ◽  
Huijie Chen ◽  
Nicole Pirozzi ◽  
Yingying Cong
Keyword(s):  
Life Cycle ◽  
Rna Virus ◽  
Spinous Process ◽  
Antiviral Drug ◽  
Host Cells ◽  
Virion Assembly ◽  
Prevention Therapy ◽  
Genome Transcription ◽  
Transcription And Replication

Coronavirus (CoV), is a single-stranded positive-sense RNA virus, which is characterized by a coronal-shaped spinous process on its surface and is the largest known RNA virus. Recently, the new outbreak of CoV was first found in Wuhan, China at the end of 2019, however, the infection is worldwide and causing high pathogenicity and mortality rates, especially in the aged population. Unfortunately, there is no available strategy to control the infection or treat patients. By reviewing the life cycle of CoV infection in host cells, including: virion attachment and entry, genome transcription and replication, and virion assembly and release, we focused on the role of viral proteins in the viral life cycle and summarized how their function could be targeted for the prevention/therapy of CoV. Thus, this information would pave the way to precisely design the antiviral drug component/vaccine against CoVs.

scholarly journals Glutamine Analogues Impair Cell Proliferation, the Intracellular Cycle and Metacyclogenesis in Trypanosoma cruzi

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1628
Author(s):  
Rodolpho Ornitz Oliveira Souza ◽  
Marcell Crispim ◽  
Ariel Mariano Silber ◽  
Flávia Silva Damasceno
Keyword(s):  
Cell Proliferation ◽  
Life Cycle ◽  
Trypanosoma Cruzi ◽  
Host Cells ◽  
Glutamine Metabolism ◽  
Complex Life Cycle ◽  
Mammalian Host ◽  
Developmental Cycle ◽  
Parasite Life Cycle

Trypanosoma cruzi is the aetiologic agent of Chagas disease, which affects people in the Americas and worldwide. The parasite has a complex life cycle that alternates among mammalian hosts and insect vectors. During its life cycle, T. cruzi passes through different environments and faces nutrient shortages. It has been established that amino acids, such as proline, histidine, alanine, and glutamate, are crucial to T. cruzi survival. Recently, we described that T. cruzi can biosynthesize glutamine from glutamate and/or obtain it from the extracellular environment, and the role of glutamine in energetic metabolism and metacyclogenesis was demonstrated. In this study, we analysed the effect of glutamine analogues on the parasite life cycle. Here, we show that glutamine analogues impair cell proliferation, the developmental cycle during the infection of mammalian host cells and metacyclogenesis. Taken together, these results show that glutamine is an important metabolite for T. cruzi survival and suggest that glutamine analogues can be used as scaffolds for the development of new trypanocidal drugs. These data also reinforce the supposition that glutamine metabolism is an unexplored possible therapeutic target.

scholarly journals Alphavirus Replication: The Role of Cardiac Glycosides and Ion Concentration in Host Cells

2020 ◽  
Vol 2020 ◽  
pp. 1-7 ◽  
Author(s):  
Kauê F. C. Souza-Souza ◽  
Cassiano F. Gonçalves-de-Albuquerque ◽  
Cláudio Cirne-Santos ◽  
Izabel C. N. P. Paixão ◽  
Patrícia Burth
Keyword(s):  
Life Cycle ◽  
Aedes Albopictus ◽  
Cardiac Glycosides ◽  
Mosquito Species ◽  
Mechanisms Of Action ◽  
Host Cells ◽  
Ion Concentration ◽  
Potential Therapeutic Target ◽  
Viral Budding

Alphaviruses are arthropod-borne viruses that can cause fever, rash, arthralgias, and encephalitis. The mosquito species Aedes aegypti and Aedes albopictus are the most frequent transmitters of alphaviruses. There are no effective vaccines or specific antivirals available for the treatment of alphavirus-related infections. Interestingly, changes in ion concentration in host cells have been characterized as critical regulators of the alphavirus life cycle, including fusion with the host cell, glycoprotein trafficking, genome translation, and viral budding. Cardiac glycosides, which are classical inhibitors of the Na+ K+ ATPase (NKA), can inhibit alphavirus replication although their mechanisms of action are poorly understood. Nonetheless, results from multiple studies suggest that inhibition of NKA may be a suitable strategy for the development of alphavirus-specific antiviral treatments. This review is aimed at exploring the role of changes in ion concentration during alphavirus replication and at considering the possibility of NKA as a potential therapeutic target for antiviral drugs.

The structure and development of the protozoonHistomonas meleagridisin the male reproductive tract of its intermediate host,Heterakis gallinarum(Nematoda)

Parasitology ◽  
1971 ◽  
Vol 63 (3) ◽  
pp. 439-445 ◽  
Author(s):  
D. L. Lee
Keyword(s):  
Life Cycle ◽  
Technical Assistance ◽  
Reproductive Tract ◽  
Vas Deferens ◽  
Final Host ◽  
The Other ◽  
Host Cells ◽  
Male Reproductive Tract ◽  
Heterakis Gallinarum

The ultrastructure and development ofHistomonas meleagridisin the reproductive tract of maleHeterakis gallinarumhas been described. In the testis the protozoon is a relatively large amoeboid organism which lies between the epithelial cells of the testis and the spermatogonia, spermatocytes and spermatids. It is similar in appearance to the invasive stage which is found in the final host and like the invasive stage, it also feeds upon the host cells by phagocytosis. In the vas deferens the protozoon lies between the host cells, where it is much smaller than the stages in the testis but still amoeboid, and inside the cells of the vas deferens.Intracellular stages are much smaller than the other stages, are rounded in appearance and cause little or no damage to the host cell. They are similar to the stages found in oocytes of the female nematode. The possible role of the male nematode in the life cycle of the protozoon is discussed.I wish to thank Mrs B. Fisher for technical assistance and Mr B. Carter for assistance with the photography.

scholarly journals Role of placenta-specific protein 1 in trophoblast invasion and migration

Reproduction ◽  
2014 ◽  
Vol 148 (4) ◽  
pp. 343-352 ◽  
Author(s):  
Wen-Lin Chang ◽  
Qing Yang ◽  
Hui Zhang ◽  
Hai-Yan Lin ◽  
Zhi Zhou ◽  
...  
Keyword(s):  
First Trimester ◽  
Specific Protein ◽  
Trophoblast Invasion ◽  
Specific Gene ◽  
Invasion And Migration ◽  
Functional Studies ◽  
And Migration ◽  
Extravillous Trophoblasts

Placenta-specific protein 1 (PLAC1), a placenta-specific gene, is known to be involved in the development of placenta in both humans and mice. However, the precise role of PLAC1 in placental trophoblast function remains unclear. In this study, the localization of PLAC1 in human placental tissues and its physiological significance in trophoblast invasion and migration are investigated by technical studies including real-time RT-PCR, in situ hybridization, immunohistochemistry, and functional studies by utilizing cell invasion and migration assays in the trophoblast cell line HTR8/SVneo as well as the primary inducing extravillous trophoblasts (EVTs). The results show that PLAC1 is mainly detected in the trophoblast columns and syncytiotrophoblast of the first-trimester human placental villi, as well as in the EVTs that invade into the maternal decidua. Knockdown of PLAC1 by RNA interference significantly suppresses the invasion and migration of HTR8/SVneo cells and shortens the distance of the outgrowth of the induced EVTs from the cytotrophoblast column of the explants. All the above data suggests that PLAC1 plays an important role in human placental trophoblast invasion and migration.

scholarly journals The ESCRT-I Subunit Tsg101 Plays Novel Dual Roles in Entry and Replication of Classical Swine Fever Virus

2020 ◽  
pp. JVI.01928-20
Author(s):  
Chun-chun Liu ◽  
Ya-yun Liu ◽  
Yan Cheng ◽  
Yun-Na Zhang ◽  
Jin Zhang ◽  
...  
Keyword(s):  
Life Cycle ◽  
Classical Swine Fever Virus ◽  
Molecular Mechanisms ◽  
Animal Health ◽  
Classical Swine Fever ◽  
Fever Virus ◽  
Host Cells ◽  
Regulatory Role ◽  
High Morbidity ◽  
Replication Process

Classical swine fever (CSF) caused by classical swine fever virus (CSFV) is one of the highly contagious diseases of swine with high morbidity and mortality, that negatively affects the pig industry worldwide, in particular China. Soon after the endocytosis of CSFV, the virus makes full use of the components of host cells to complete its life cycle. Endocytosis sorting complex required for transport (ESCRT) system is a central molecular machine for membrane protein sorting and scission in eukaryotic cells that plays an essential role in many physiological, metabolic processes including invasion and egress of envelope viruses. However, the molecular mechanism that ESCRT regulates the replication of CSFV is unknown. In this study, we demonstrated that the ESCRT-I complex Tsg101 protein participates in Clathrin-mediated endocytosis of CSFV and also involved in CSFV trafficking. Tsg101 assisted the virus in entering the host cell through the late endosome (Rab7 and Rab9), and finally to reach the lysosome (Lamp-1). Interestingly, Tsg101 is also involved in the viral replication process by interacting with nonstructural proteins 4B and 5B of CSFV. Finally, confocal microscopy showed that the replication complex of Tsg101 and dsRNA or NS4B and NS5B protein was close to the endoplasmic reticulum (ER), not Golgi in the cytoplasm. Collectively, our finding highlights that Tsg101 regulates the process of CSFV entry and replication, indicating that the ESCRT plays an important role in the life cycle of CSFV. Thus, ESCRT molecules could serve as therapeutic targets to combat CSFV infection.IMPORTANCE CSF, caused by CSFV, is one of the notifiable diseases by the World Organization for Animal Health (OIE) and causes significant financial losses to the pig industry globally. The ESCRT machinery plays an important regulatory role in several members of the genus Flavivirus and Hepacivirus within the family Flaviviridae, such as hepatitis C virus, Japanese encephalitis virus, and dengue virus. Previous reports have shown that assembling and budding of these viruses require ESCRT. However, the role of ESCRT in Pestivirus infection remains to be elucidated. We determined the molecular mechanisms of the regulation of CSFV infection by the major subunit Tsg101 of ESCRT-I. Interestingly, Tsg101 plays an essential regulatory role in both Clathrin-mediated endocytosis and genome replication of CSFV. Overall, the results of this study provide further insights into the molecular function of ESCRT-I complex protein Tsg101 during CSFV infection, which may serve as a molecular target for Pestivirus inhibitors.

scholarly journals Advances in Understanding Leishmania Pathobiology: What Does RNA-Seq Tell Us?

2021 ◽  
Vol 9 ◽  
Author(s):  
Tamara Salloum ◽  
Sima Tokajian ◽  
Robert P. Hirt
Keyword(s):  
Life Cycle ◽  
Gut Microbiota ◽  
Potential Role ◽  
Clinical Manifestations ◽  
Host Cells ◽  
Mammalian Host ◽  
Rna Seq ◽  
Skin Microbiota ◽  
Vector Borne

Leishmaniasis is a vector-borne disease caused by a protozoa parasite from over 20 Leishmania species. The clinical manifestations and the outcome of the disease vary greatly. Global RNA sequencing (RNA-Seq) analyses emerged as a powerful technique to profile the changes in the transcriptome that occur in the Leishmania parasites and their infected host cells as the parasites progresses through their life cycle. Following the bite of a sandfly vector, Leishmania are transmitted to a mammalian host where neutrophils and macrophages are key cells mediating the interactions with the parasites and result in either the elimination the infection or contributing to its proliferation. This review focuses on RNA-Seq based transcriptomics analyses and summarizes the main findings derived from this technology. In doing so, we will highlight caveats in our understanding of the parasite’s pathobiology and suggest novel directions for research, including integrating more recent data highlighting the role of the bacterial members of the sandfly gut microbiota and the mammalian host skin microbiota in their potential role in influencing the quantitative and qualitative aspects of leishmaniasis pathology.

Ionic homeostasis and subcellular element compartmentation

1990 ◽  
Vol 48 (2) ◽  
pp. 150-151
Author(s):  
Ann LeFurgey ◽  
Peter Ingram ◽  
J.J. Blum ◽  
M.C. Carney ◽  
L.A. Hawkey ◽  
...  
Keyword(s):  
Leishmania Major ◽  
Ionic Homeostasis ◽  
X Ray ◽  
Functional Studies ◽  
Cell Compartments ◽  
X Ray Imaging ◽  
Resolution Electron ◽  
Multiple Cell ◽  
Role Of Zn

Subcellular compartments commonly identified and analyzed by high resolution electron probe x-ray microanalysis (EPXMA) include mitochondria, cytoplasm and endoplasmic or sarcoplasmic reticulum. These organelles and cell regions are of primary importance in regulation of cell ionic homeostasis. Correlative structural-functional studies, based on the static probe method of EPXMA combined with biochemical and electrophysiological techniques, have focused on the role of these organelles, for example, in maintaining cell calcium homeostasis or in control of excitation-contraction coupling. New methods of real time quantitative x-ray imaging permit simultaneous examination of multiple cell compartments, especially those areas for which both membrane transport properties and element content are less well defined, e.g. nuclei including euchromatin and heterochromatin, lysosomes, mucous granules, storage vacuoles, microvilli. Investigations currently in progress have examined the role of Zn-containing polyphosphate vacuoles in the metabolism of Leishmania major, the distribution of Na, K, S and other elements during anoxia in kidney cell nuclel and lysosomes; the content and distribution of S and Ca in mucous granules of cystic fibrosis (CF) nasal epithelia; the uptake of cationic probes by mltochondria in cultured heart ceils; and the junctional sarcoplasmic retlculum (JSR) in frog skeletal muscle.

ASPECTS IN BUILDING A COMPANY WEB-SITE AND ITS ROLE FOR THE DEVELOPMENT OF BUSINESS

2018 ◽  
pp. 117-124
Author(s):  
Petar Halachev ◽  
Victoria Radeva ◽  
Albena Nikiforova ◽  
Miglena Veneva
Keyword(s):  
Life Cycle ◽  
Web Site ◽  
The Internet ◽  
A Company ◽  
The Web ◽  
Design Construction ◽  
Made In ◽  
Site Types

This report is dedicated to the role of the web site as an important tool for presenting business on the Internet. Classification of site types has been made in terms of their application in the business and the types of structures in their construction. The Models of the Life Cycle for designing business websites are analyzed and are outlined their strengths and weaknesses. The stages in the design, construction, commissioning, and maintenance of a business website are distinguished and the activities and requirements of each stage are specified.

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