Nudivirus

Key takeaways

Nudivirus belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Nudivirus to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Nudivirus from memory before moving on to harder problems.

Reference excerpt

Nudiviruses are a genus of arthropod viruses that constitute the family Nudiviridae. Insects and marine crustaceans serve as natural hosts to this family of viruses. Nudiviruses are double-stranded DNA viruses, with their genome notably ranging from 130 to 140 kilobases in length. There are 29 species in this family, assigned to 6 genera. Diseases associated with this family include: death in larvae, and chronic disease in adults.

Taxonomy The family Nudiviridae contains the following genera:

Alphanudivirus Betanudivirus Deltanudivirus Epsilonnudivirus Gammanudivirus Zetanudivirus

Classification History During their first discovery, nudiviruses were classified as a subgroup in the Baculoviridae family. Originally it was assumed that nudiviruses were nooccluded baculoviruses. In 2007, the genus Nudivirus was proposed to include viruses similar to the Oryctes rhinoceros virus. In 2013, Nudiviruses were classified as the family Nudiviridae. Nudiviruses are assigned to the class Naldaviricetes that contains three other large dsDNA virus families: Baculoviridae, Hytrosaviridae and Nimaviridae.

Species Nudiviruses infect only insects and marine crustaceans.

Drosophila innubila nudivirus (DiNV) – Drosophila innubila (Diptera) Gryllus bimaculatus nudivirus (GbNV) – black cricket (Teleogryllus commodus) Heliothis zea nudivirus 1 (HzNV-1) – cotton bollworm Helicoverpa zea nudivirus 2 (HzNV-2 formally known as GSV)– cotton bollworm Homarus gammarus nudivirus (HgNV)- European lobster (Homarus gammarus) Oryctes rhinoceros nudivirus (OrNV)– rhinoceros beetle Oryctes rhinoceros Penaeus monodon nudivirus (PmNV) – Black tiger shrimp Dikerogammarus haemobaphes nudivirus (DhNV) – an amphipod crustacean (Dikerogammarus haemobaphes) Menippe mercenaria nudivirus (MmNV) – Florida stone crab Callinectes sapidus nudivirus (CsNV)- Blue crab Diabrotica undecimpunctata howardi nudivirus (DuhNV) – Spotted cucumber beetle Tomelloso virus (TV) – Drosophila melanogaster Osmia cornuta nudivirus (OcNV) – European orchard bee Crangon crangon nudivirus (CcNV) – Brown Shrimp Carcinus maenas bacilliform nudivirus (CmNV) – European Green Crab Tipula oleracea nudivirus (ToNV) – Marsh Crane Fly Carcinus maenas bacilliform nudivirus (CmNV) – Faxonius propinquus nudivirus (FpNV) – Northern Clear Water Crayfish Faxonius virilis nudivirus (FvNV) – Virile Crayfish Faxonius rusticus nudivirus (FrNV) – Rusty Crayfish

Virus Transmission Transmission of nudiviruses occurs horizontally by feeding, mating and vertically from mother to offspring. Infections can be lethal for the larvae and can possibly reduce the fitness of the host by reducing offspring production and survival among adults.

Structure and life cycle

Nudiviruses are double stranded DNA viruses, characterized by their rod shape. Their virions are made of a single nucleocapsid surrounded by an envelope and range from 30 nm to 120 nm in length. They replicate in the nucleus of infected host cells and in some parasitoid wasp species, a nudivirus genome, in proviral form, is integrated into the wasp genome and produces virus like particles called polydnaviruses that are injected into lepidopteran larvae and are thought to facilitate parasitization of the larvae. Nudiviruses have localized infection and are associated with specific cell pathogenesis and varies among species. Vesicles containing virions have been observed for HzNV-2 and OrNV and aid in infecting subsequent cells. Virions sexually transmitted during mating, like Hznv-2, target reproductive tissues, cause the malformation of reproductive tissues in infected adult Helicoverpa Zea. In cells, enveloped and non enveloped particles were observed in the nucleus and have been found to successfully replicate in infect ovarian moth cell lines, but did not replicate in fat body cells. In OrNV, replication occurs in the nucleus in midgut and fat body cells. In TpNV, replication occurs in the nucleus of the salvalary glands. The specific cell localization is a distinctive characteristic that differentiates nudivruses from baculoviruses. Three species form Occlusion bodies (OBs), ToNV, PmNV and OrNV. In PmNV OBs are transmitted orally and are sensitive to acid conditions. Host proteins may be involved in the formation of nudiviral OBs. Currently, there is not a general life cycle established for nudiviruses.

Genome

Gene content comparison and phylogenetic analyses show that nudiviruses share 20 core genes with baculoviruses and form a monophyletic sister group with them. Fossil calibration estimate this association arose 100 million years ago(Mya), while the last common ancestor of nudiviruses and baculoviruses existed approximately 312 Mya. Baculoviruses and nudiviruses differ in gene content, genome organization, cytopathology, infection of adults and most likely in host range. The 20 core genes common in both baculoviruses and nudiviruses are involved in RNA transcription, DNA replication, virion structural components and many other functions. Gene content and sequence similarity suggest that the nudiviruses GbNV, HzNV-1, and OrNV form a monophyletic group of nonoccluded double-stranded DNA viruses, which separated from the baculovirus lineage before this radiated into dipteran-, hymenopteran-, and lepidopteran-specific clades of occluded nucleopolyhedroviruses and granuloviruses. The coding sequences vary among the nudivirus species and encode between 87 and 154 proteins depending on the species. The order of the genes in the genomes of the viruses found in nudiviridae are poorly conserved. There are 32 core genes conserved among nudiviruses that are involved in various viral functions.

Transcription: lef-4, lef-5, lef-8, lef-9, p47 Infectivity: pif-0, pif-1, pif-2, pif-3, pif-4, pif-5, pif-6 Package/Assembly/Morphogenesis: vip91, 38k, p33, p6.9, vlf-1, vp39, ac81 DNA replication/repair/recombination: dnapol, helicase, helicase-2, integrase, fen-1 Nucleotide metabolism: tk1, tk2, tk3 Unknown function: GbNV gp19-like, GbNV gp51-like, GbNV gp58-like, GbNV gp67-like, 11K-like. The conservation of the 8 pif proteins, suggest the mode of infection for nudiviruses is conserved.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Nudivirus

Start with the simplest possible case. Write down what Nudivirus claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Nudivirus before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Nudivirus ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Nudivirus

In research: Nudivirus appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Nudivirus in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Nudivirus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Nudiviridae, Virus families, so understanding it makes those chapters shorter.
In everyday life: Look for Nudivirus outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Nudivirus in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Nudivirus means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Nudivirus out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Nudivirus in simple terms?

Nudiviruses are a genus of arthropod viruses that constitute the family Nudiviridae. Insects and marine crustaceans serve as natural hosts to this family of viruses.

Why does Nudivirus matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Nudivirus?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Nudivirus.