Virology News

"Viral protein synthesis is completely dependent upon the translational machinery of the host cell. However, many RNA virus transcripts have marked structural differences from cellular mRNAs that preclude canonical translation initiation, such as the absence of a 5′ cap structure or the presence of highly structured 5′UTRs containing replication and/or packaging signals. Furthermore, whilst the great majority of cellular mRNAs are apparently monocistronic, RNA viruses must often express multiple proteins from their mRNAs. In addition, RNA viruses have very compact genomes and are under intense selective pressure to optimize usage of the available sequence space. Together, these features have driven the evolution of a plethora of non-canonical translational mechanisms in RNA viruses that help them to meet these challenges. Here, we review the mechanisms utilized by RNA viruses of eukaryotes, focusing on internal ribosome entry, leaky scanning, non-AUG initiation, ribosome shunting, reinitiation, ribosomal frameshifting and stop-codon readthrough. The review will highlight recently discovered examples of unusual translational strategies, besides revisiting some classical cases."

Great article for anyone interested in how RNA viruses subvert cellular processes.

"Viral STDs make up the modern "4-H club." Herpes simplex virus (HSV), human papilloma virus (HPV), hepatitis (B and C), and HIV are the most common STDs, causing pain, cancer, liver disease and AIDS, respectively.

Condoms significantly decrease transmission rates of the most life-threatening viruses, HIV and hep B and C.

Unfortunately, condoms do not do an adequate job of protecting against human papilloma or herpes simplex virus infections. Women diagnosed with HPV are often mystified and frustrated, having been "super careful," or picky, in choosing intimate partners and faithfully using condoms for all intercourse.

But UCSF researchers have shown these viruses to be present on genital skin with no symptoms that might prompt diagnosis and treatment. That means HPV and HSV can be deposited on the condom's outer surface from viral particles living on the scrotum, penile shaft not covered by the condom or vaginal/vulvar tissues."

Interesting - because it's been known a while that condoms are less effective in preventing spread of HPV than for bacterial STDs and HIV, and now we know why.  The only things that can really prevent the transmission of these agents, in the absence of abstinence, is vaccination.

"There's buzz about a new treatment that could save bee populations from a deadly virus.
Researchers at the University of Manitoba have found a way to suppress the deformed-wing virus (DWV), which has had catastrophic effects on bee colonies worldwide, causing many to have crumpled or deformed wings.
Entomology PhD student Suresh Desai fed his bees double-stranded RNA, a treatment that prevented the virus from expressing itself in the host.
"It gives us a little bit of hope that we can manage this virus, because there is no control mechanism right now," he said.
The study, published online on Insect Molecular Biology on June 12, showed bees fed the double-stranded RNA in a syrup and then inoculated with the virus had a much better survival rate than those who weren't. RNA is much like DNA, but is in a single strand. It carries the genetic material of some viruses, including DWV. RNA is taken from the DWV and then converted into a double strand. When introduced in the bee, it suppresses the viral RNA."

I find it fascinating that the dsRNA that we as plant virologists grew to know and love in the 1980s - because it's easier to isolate from plants than ssRNA, and far more stable - has newly become so much more useful as an anti-viral therapeutic.  And you can isolate a tonne of dsRNA from virus-infected insects, too, so it's also interesting why exogenous material should be effective.

At least 10 Zimbabwean members of parliament get circumcised as part of a campaign to reduce HIV and Aids cases.

Might stop 'em having sex for a while, which would also help!

Greece has been a mainstay in the international press as it endures harsh austerity measures in the face of the global economic crisis. But recent news reports have also focused on another disturbing reality. [1] At the end of April, Greek police began systematically arresting sex workers, forcing them to undergo HIV testing, and posting the names and photographs of those who test HIV-positive on official police websites. The sex workers face criminal charges of intentionally causing serious bodily harm, even though there is no evidence they were aware of their HIV status.

The Joint United Nations Programme on HIV/AIDS (UNAIDS), Amnesty International, the Global Network of Sex Work Projects and the Global Network of People Living with HIV/AIDS, have all condemned the Greek authorities' actions as incompatible with human rights and discordant with proven public health measures to prevent HIV transmission. State-sanctioned forced HIV testing of sex workers also occurs elsewhere, including in the southern African country of Malawi. But in Malawi, something inspiring has happened - sex workers are fighting back.

Couldn't resist this one, and had fun dreaming up all sorts of punchlines.  Like" "They're both annoying, they both hurt, and they make you drool".  Sorry...!

It's actually a sales pitch for a salivary HPV test, but the virology underlying it is interesting: oral sex can lead to oral HPV infection with high-risk types that are associated with oral cancers.  However, in the absence of oral sex you can also get high-risk types in the oral area, and antibodies to the viruses can be detected in saliva without any oral infection.

Vaccination against hepatitis B seems to protect against the virus for 25 years, suggesting that booster shots are unnecessary, according to a study from Taiwan that covered several thousand people.  “Universal vaccination in infancy provides long-term protection,” wrote lead author Yen-Hsuan Ni, from the National Taiwan University in Taipei.

Good news indeed - because chronic infection with HBV, which occurs more often if you get it as a child, leads to a far higher incidence of liver cancer and a lifelong carrier status.  And there's over 300 million people infected, so it's a SERIOUS problem.

In brome mosaic virus, both the replication of the genomic (+)-RNA strands and the transcription of the subgenomic RNA are carried out by the viral replicase. The production of (−)-RNA strands is dependent on the formation of an AUA triloop in the stem–loop C (SLC) hairpin in the 3′-untranslated region of the (+)-RNA strands. Two alternate hypotheses have been put forward for the mechanism of subgenomic RNA transcription. One posits that transcription commences by recognition of at least four key nucleotides in the subgenomic promoter by the replicase. The other posits that subgenomic transcription starts by binding of the replicase to a hairpin formed by the subgenomic promoter that resembles the minus strand promoter hairpin SLC. In this study, we have determined the three-dimensional structure of the subgenomic promoter hairpin using NMR spectroscopy. The data show that the hairpin is stable at 30°C and that it forms a pseudo-triloop structure with a transloop base pair and a nucleotide completely excluded from the helix. The transloop base pair is capped by an AUA triloop that possesses an extremely well packed structure very similar to that of the AUA triloop of SLC, including the formation of a so-called clamped-adenine motif. The similarities of the NMR structures of the hairpins required for genomic RNA and subgenomic RNA synthesis show that the replicase recognizes structure rather than sequence-specific motifs in both promoters.

BMV!! I worked on bromoviruses in general and BMV in particular from 1977 to around 1985, and collected every paper on them - and especially the mol biol. It was always obvious, once the sequences were known, that origins of replication and the subgenomic promoter were not sequence-delimited - and now we see that it's a structure. Cool stuff!!

South Africa recently claimed a victory. In May, it won the right to host the world’s biggest radio telescope.  The $2 billion project, said Derek Hanekom, Deputy Minister of Science and Technology at BIO’s ‘The BRICS and Beyond’ special session (June 18) sent out a sign that the country has left behind its troubled past and is ready for business. Beyond astronomy, and its azure skies, South Africa is a market poised for growth and a gateway to the rest of the continent. Over the last 20 years, the government has embraced “innovative thinking,” said Hanekom. While addressing poverty issues, and providing help for the 5.6 million people who are HIV positive, the state has come up with game plan to spur the economy. South Africa, as most other BRIC countries have done before, is embracing the idea of a Bioeconomy as an engine for growth. The state sees potential in genetically modified crops for pest and drought resistance and grasses as cellulosic material for second-generation biofuels. Exploiting algae is also high on the agenda, in the short term, as a source of protein for animal feed, and in the long term as a biofuel.

Ja.  Really??  Why is it so damn hard to get money, then??

The health of the honeybee and, indirectly, global crop production are threatened by several biotic and abiotic factors, which play a poorly defined role in the induction of widespread colony losses. Recent descriptive studies suggest that colony losses are often related to the interaction between pathogens and other stress factors, including parasites. Through an integrated analysis of the population and molecular changes associated with the collapse of honeybee colonies infested by the parasitic mite Varroa destructor, we show that this parasite can de-stabilise the within-host dynamics of Deformed wing virus (DWV), transforming a cryptic and vertically transmitted virus into a rapidly replicating killer, which attains lethal levels late in the season. The de-stabilisation of DWV infection is associated with an immunosuppression syndrome, characterized by a strong down-regulation of the transcription factor NF-κB. The centrality of NF-κB in host responses to a range of environmental challenges suggests that this transcription factor can act as a common currency underlying colony collapse that may be triggered by different causes. Our results offer an integrated account for the multifactorial origin of honeybee losses and a new framework for assessing, and possibly mitigating, the impact of environmental challenges on honeybee health.

Egypt, which has the highest number of deaths due to bird flu globally, is to produce its first vaccine to combat the virus, the National Research Centre (NRC) in Cairo has announced.

The Government has been importing vaccines at high prices to fight this national problem but a locally produced vaccine will be available in the local market at LE305 (about $60) for 100 doses.

Which is a LOT more than we can do, here in supposedly technologically-advanced South Africa.  Ah, well - suppose the EU regulations about ostriches mean we can't vaccinate them anyway, and they don't have H5N1 - yet.

Jun 15, 2012 (CIDRAP News) – The 2011-12 flu season in most temperate countries of the Northern Hemisphere started later than usual, except for North Africa, and was mild in many countries, the World Health Organization (WHO) said today in a wrap-up report.

The circulating flu strains varied widely by country and even by region, according to WHO report, which appeared in its Weekly Epidemiological Record. For example, in North America, the 2009 H1N1 virus predominated in Mexico, with H3N2 dominating in the United States, and influenza B taking the lead in most parts of Canada.

In temperate parts of Asia, influenza B peaked first in China and Mongolia, followed by a rise in H3N2 activity later in the season. The reverse pattern was seen in South Korea and Japan.

Many countries saw doctors' visits for flulike illness at or below last season's levels, but Japan reported its highest number of confirmed flu cases since 2002, except for during the 2009 pandemic period, the WHO report said.

Some European countries such as Spain and France reported excess mortality in older adults, much of it related to H3N2 that circulated in those areas. European officials also reported that the 2009 H1N1 virus was overrepresented in cases of severe influenza.

New research from the University of North Carolina School of Medicine demonstrates that breast milk in a humanized mouse model has a strong virus killing effect and protects against oral transmission of HIV.