A cytological and immunological study of Tipula iridescent virus-infected Galleria mellonella larval hemocytes

Yule, B.Gillian; Lee, Peter E.

doi:10.1016/0042-6822(73)90440-6

Cited by 23 publications

(5 citation statements)

References 19 publications

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“…More marvelous still was the ensuing discovery that the spherical poxvirus envelopes form progressively by expansion of crescentshaped precursors that display the same curvature as the final spheres, but start off incomplete and open to the cytoplasm (Bang, 1950;Gaylord and Melnick, 1953;Bernhard et al, 1954;Morgan et al, 1954Morgan et al, , 1955. This very unusual form of membrane biogenesis has turned out to be quite novel, although it is seen in modified form in many of the large icosahedral DNA viruses that also form in the cytoplasm of infected cells (Smith, 1958;Breese and Deboer, 1966;Yule and Lee, 1973;Nunes et al, 1975;Mathieson and Lee, 1981;Meints et al, 1984Meints et al, , 1986Brookes et al, 1998;Cobbold et al, 2000;Iyer et al, 2001;Van Etten et al, 2002;Stasiak et al, 2003). Certainly, no hostcell membranes have ever shown this pattern of biogenesis.…”

Section: Introductionmentioning

confidence: 99%

Deep-etch EM reveals that the early poxvirus envelope is a single membrane bilayer stabilized by a geodetic “honeycomb” surface coat

Heuser

2005

The Journal of Cell Biology

101

137

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Three-dimensional “deep-etch” electron microscopy (DEEM) resolves a longstanding controversy concerning poxvirus morphogenesis. By avoiding fixative-induced membrane distortions that confounded earlier studies, DEEM shows that the primary poxvirus envelope is a single membrane bilayer coated on its external surface by a continuous honeycomb lattice. Freeze fracture of quick-frozen poxvirus-infected cells further shows that there is only one fracture plane through this primary envelope, confirming that it consists of a single lipid bilayer. DEEM also illustrates that the honeycomb coating on this envelope is completely replaced by a different paracrystalline coat as the poxvirus matures. Correlative thin section images of infected cells freeze substituted after quick-freezing, plus DEEM imaging of Tokuyasu-type cryo-thin sections of infected cells (a new application introduced here) all indicate that the honeycomb network on immature poxvirus virions is sufficiently continuous and organized, and tightly associated with the envelope throughout development, to explain how its single lipid bilayer could remain stable in the cytoplasm even before it closes into a complete sphere.

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Section: Introductionmentioning

confidence: 99%

Deep-etch EM reveals that the early poxvirus envelope is a single membrane bilayer stabilized by a geodetic “honeycomb” surface coat

Heuser

2005

The Journal of Cell Biology

101

137

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“…ASFV shares the genomic organization of the Poxviridae and the striking icosahedral symmetry of the Iridoviridae (1, 7, 21) and has been described as a missing evolutionary link between poxviruses and iridoviruses (31). A possible evolutionary link between ASFV and the Iridoviridae is supported by the sequence homology between the major capsid proteins of the viruses (33) and close similarities in morphology and morphogenesis (2,21,26,27,30,34,35,43). Early studies on negatively stained and freeze-dried ASF virions have shown capsid layers 190 nm in diameter containing as many as 2,000 capsomeres organized into a hexagonal lattice, suggesting icosahedral symmetry (1, 7, 21).…”

mentioning

confidence: 99%

A Virally Encoded Chaperone Specialized for Folding of the Major Capsid Protein of African Swine Fever Virus

Cobbold

Windsor

Wileman

2001

J Virol

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It is generally believed that cellular chaperones facilitate the folding of virus capsid proteins, or that capsid proteins fold spontaneously. Here we show that p73, the major capsid protein of African swine fever virus (ASFV) failed to fold and aggregated when expressed alone in cells. This demonstrated that cellular chaperones were unable to aid the folding of p73 and suggested that ASFV may encode a chaperone. An 80-kDa protein encoded by ASFV, termed the capsid-associated protein (CAP) 80, bound to the newly synthesized capsid protein in infected cells. The 80-kDa protein was released following conformational maturation of p73 and dissociated before capsid assembly. Coexpression of the 80-kDa protein with p73 prevented aggregation and allowed the capsid protein to fold with kinetics identical to those seen in infected cells. CAP80 is, therefore, a virally encoded chaperone that facilitates capsid protein folding by masking domains exposed by the newly synthesized capsid protein, which are susceptible to aggregation, but cannot be accommodated by host chaperones. It is likely that these domains are ultimately buried when newly synthesized capsid proteins are added to the growing capsid shell.Chaperones prevent the irreversible aggregation of proteins in cells (15,16). The Hsp70/DnaK chaperones bind short stretches of hydrophobic amino acids exposed in nascent chains emerging from ribosomes. Proteins released from Hsp70 attempt to fold and bury hydrophobic domains, but if unsuccessful they rebind or are transferred to ring chaperonins such as GroEL and GroES or the TCP1 (TriC/CCT) chaperonin. A broad spectrum of newly synthesized polypeptides associate with these chaperones "in vivo," and the chaperone pathway is viewed as one of broad specificity and high capacity (15,16,19,37). The folding of some proteins, however, requires specialized chaperones, and these may be needed to coordinate protein folding with subunit assembly (18). The PapD chaperones of Escherichia coli, for example, reduce nonproductive interactions between pilin subunits before they are assembled into the base of the growing pilus (3).The careful coordination of protein folding and subunit assembly are important during the assembly of icosahedral viruses. Icosahedral capsids contain an exact number of protein subunits assembled into an ordered lattice; the simplest ones contain 60 identical subunits, while the largest ones contain several thousand. Capsid subunits are synthesized as monomers in the cytosol and expose domains that are ultimately buried during capsid assembly. In order to prevent nonproductive capsid aggregation, it is important that inappropriate interactions between these domains are minimized before delivery of the capsid subunit onto the growing capsid shell. For some viruses aggregation may be prevented by host chaperones (14,17,24,25) or through assembly with scaffold proteins (22,29).The Iridoviridae and African swine fever virus (ASFV) virus are a group of cytoplasmic DNA viruses with very large capsids. ASFV shares th...

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“…Cricket iridovirus (CrIV) caused fatal infections in larvae of the greater wax moth [61,116]. Tipula iridescent virus (TIV) can infect and multiply in hemocytes of G. mellonella larvae [269,[276][277][278][279][280]. Tipula iridescent virus was consistently infectious and caused complete mortality among G. mellonella, with the average period to death occurring at about 14 days after injection [269].…”

Section: Galleria Mellonellamentioning

confidence: 99%

A Systematic Review on Viruses in Mass-Reared Edible Insect Species

Bertola

2021

Viruses

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Edible insects are expected to become an important nutrient source for animals and humans in the Western world in the near future. Only a few studies on viruses in edible insects with potential for industrial rearing have been published and concern only some edible insect species. Viral pathogens that can infect insects could be non-pathogenic, or pathogenic to the insects themselves, or to humans and animals. The objective of this systematic review is to provide an overview of the viruses detected in edible insects currently considered for use in food and/or feed in the European Union or appropriate for mass rearing, and to collect information on clinical symptoms in insects and on the vector role of insects themselves. Many different virus species have been detected in edible insect species showing promise for mass production systems. These viruses could be a risk for mass insect rearing systems causing acute high mortality, a drastic decline in growth in juvenile stages and in the reproductive performance of adults. Furthermore, some viruses could pose a risk to human and animal health where insects are used for food and feed.

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A cytological and immunological study of Tipula iridescent virus-infected Galleria mellonella larval hemocytes

Cited by 23 publications

References 19 publications

Deep-etch EM reveals that the early poxvirus envelope is a single membrane bilayer stabilized by a geodetic “honeycomb” surface coat

Deep-etch EM reveals that the early poxvirus envelope is a single membrane bilayer stabilized by a geodetic “honeycomb” surface coat

A Virally Encoded Chaperone Specialized for Folding of the Major Capsid Protein of African Swine Fever Virus

A Systematic Review on Viruses in Mass-Reared Edible Insect Species

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