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Tsetse Salivary Gland Hypertrophy Virus: Hope or Hindrance for Tsetse Control?
Adly M. M. Abd-Alla ,Andrew G. Parker,Marc J. B. Vreysen,Max Bergoin
PLOS Neglected Tropical Diseases , 2011, DOI: 10.1371/journal.pntd.0001220
Abstract: Many species of tsetse flies (Diptera: Glossinidae) are infected with a virus that causes salivary gland hypertrophy (SGH), and flies with SGH symptoms have a reduced fecundity and fertility. The prevalence of SGH in wild tsetse populations is usually very low (0.2%–5%), but higher prevalence rates (15.2%) have been observed occasionally. The successful eradication of a Glossina austeni population from Unguja Island (Zanzibar) using an area-wide integrated pest management approach with a sterile insect technique (SIT) component (1994–1997) encouraged several African countries, including Ethiopia, to incorporate the SIT in their national tsetse control programs. A large facility to produce tsetse flies for SIT application in Ethiopia was inaugurated in 2007. To support this project, a Glossina pallidipes colony originating from Ethiopia was successfully established in 1996, but later up to 85% of adult flies displayed symptoms of SGH. As a result, the colony declined and became extinct by 2002. The difficulties experienced with the rearing of G. pallidipes, epitomized by the collapse of the G. pallidipes colony originating from Ethiopia, prompted the urgent need to develop management strategies for the salivary gland hypertrophy virus (SGHV) for this species. As a first step to identify suitable management strategies, the virus isolated from G. pallidipes (GpSGHV) was recently sequenced and research was initiated on virus transmission and pathology. Different approaches to prevent virus replication and its horizontal transmission during blood feeding have been proposed. These include the use of antiviral drugs such as acyclovir and valacyclovir added to the blood for feeding or the use of antibodies against SGHV virion proteins. In addition, preliminary attempts to silence the expression of an essential viral protein using RNA interference will be discussed.
Deformed wing virus is not related to honey bees' aggressiveness
Agnès Rortais, Diana Tentcheva, Alexandros Papachristoforou, Laurent Gauthier, Gérard Arnold, Marc Colin, Max Bergoin
Virology Journal , 2006, DOI: 10.1186/1743-422x-3-61
Abstract: Temporal polyethism is widespread among social hymenopteran, and particularly in the honey bee Apis mellifera L. [1,2]. The behavioural shifts that occur as a worker ages are associated with physiological changes such as variation in juvenile hormone titres in the insect haemolymph [3] or variation in octopamine levels in the bee head [4]. As the expression patterns of the mRNA in honey bee brains predict behavioural changes [5], one can expect that viral infections located in heads might have profound effects on the behaviour of bees. Until now, only one insect virus – namely the sacbrood virus (SBV), has been found to modify workers tasks. SBV infected adults were found to forage earlier in life than controls, and most infected foragers failed in collecting pollen; these effects were attributed to physiological changes due to viral infection [6,7]. Recently, the kakugo virus (KV), which was only detected in the brain of aggressive workers of Italian bees by real-time PCR, was suggested to trigger behavioural changes in honey bees [8].Among the 13 honey bee viruses described in Apis mellifera L. [9], the deformed wing virus (DWV) is one of the most common [10-12]. DWV belongs to the novel family of the Iflaviridae and its genome consists of a single strand positive RNA encompassing a single open reading frame which codes for both structural and non structural polypeptides [13]. DWV is suspected to induce typical injuries on the wings of infected workers, mostly in those heavily infested with the ectoparasite Varroa destructor [9]. In honey bee colonies, association of DWV with mite infestations has been largely documented [10,14-16]. DWV was further evidenced in different worker, queen and drone organs by quantitative RT-PCR and in situ hybridisation [17,18] indicating that it might have a considerable degree of tissue specificity.The DWV and KV sequences show a great homology (98%, at the nucleotide level). Considering this, we tested whether DWV, like KV, is rela
Localization of deformed wing virus infection in queen and drone Apis mellifera L
Julie Fievet, Diana Tentcheva, Laurent Gauthier, Joachim de Miranda, Fran?ois Cousserans, Marc Colin, Max Bergoin
Virology Journal , 2006, DOI: 10.1186/1743-422x-3-16
Abstract: More than fifteen viruses have been described from honey bees (Apis mellifera L.) to date, most of which are 30 nm isometric particles containing a single positive strand RNA genome [1]. These viruses are widespread in honey bee colonies [2,3] with multiple virus infections in the same bee colony a common feature [3-7]. These infections are generally low level and symptomless [4,8], with occasional outbreaks producing clinical signs at individual bee or colony level [1]. Many infected bees remain asymptomatic and functional, although usually with a reduced life span [9]. This relatively benign scenario changed with the arrival of Varroa destructor which activates and transmits several of these viruses, resulting in greatly elevated incidence of these viruses [1,3,10]. Of these, deformed wing virus (DWV) appears to be closely associated with Varroa destructor infestation of bee colonies [11-14].Queen fecundity is a central element in colony performance for honey production that could be impaired by viral infections [6,15]. For instance, the undesired queen supersedure observed regularly by beekeepers may be related to viral infections. There are several reasons for untimely queen changing by workers in a colony, such as pathological impairment of its reproductive functions, lack of pheromone emission and lack of fully active spermatozoa in the spermatheca and decreasing sperm viability with the ageing of queens [16]. Very few investigations have been published regarding factors affecting the fertility of the queens and the drones [17].To study more precisely the etiology of DWV infection and to identify pathological effects on bee reproduction, we have attempted to localize DWV nucleic acid and viral particles in queen and drone organs by in situ hybridization and immunohistology. In parallel, tissue samples were analyzed by quantitative PCR to estimate the number of viral genome copies in the organs.DWV was detected by triplicate quantitative RT-PCR assays [14] in 6
The Antiviral Drug Valacyclovir Successfully Suppresses Salivary Gland Hypertrophy Virus (SGHV) in Laboratory Colonies of Glossina pallidipes
Adly M.M. Abd-Alla, Henry Adun, Andrew G. Parker, Marc J.B. Vreysen, Max Bergoin
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0038417
Abstract: Many species of tsetse flies are infected with a virus that causes salivary gland hypertrophy (SGH) symptoms associated with a reduced fecundity and fertility. A high prevalence of SGH has been correlated with the collapse of two laboratory colonies of Glossina pallidipes and colony maintenance problems in a mass rearing facility in Ethiopia. Mass-production of G. pallidipes is crucial for programs of tsetse control including the sterile insect technique (SIT), and therefore requires a management strategy for this virus. Based on the homology of DNA polymerase between salivary gland hypertrophy virus and herpes viruses at the amino acid level, two antiviral drugs, valacyclovir and acyclovir, classically used against herpes viruses were selected and tested for their toxicity on tsetse flies and their impact on virus replication. While long term per os administration of acyclovir resulted in a significant reduction of productivity of the colonies, no negative effect was observed in colonies fed with valacyclovir-treated blood. Furthermore, treatment of a tsetse colony with valacyclovir for 83 weeks resulted in a significant reduction of viral loads and consequently suppression of SGH symptoms. The combination of initial selection of SGHV-negative flies by non-destructive PCR, a clean feeding system, and valacyclovir treatment resulted in a colony that was free of SGH syndromes in 33 weeks. This is the first report of the use of a drug to control a viral infection in an insect and of the demonstration that valacyclovir can be used to suppress SGH in colonies of G. pallidipes.
Viruses Associated with Ovarian Degeneration in Apis mellifera L. Queens
Laurent Gauthier,Marc Ravallec,Magali Tournaire,Fran?ois Cousserans,Max Bergoin,Benjamin Dainat,Joachim R. de Miranda
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0016217
Abstract: Queen fecundity is a critical issue for the health of honeybee (Apis mellifera L.) colonies, as she is the only reproductive female in the colony and responsible for the constant renewal of the worker bee population. Any factor affecting the queen's fecundity will stagnate colony development, increasing its susceptibility to opportunistic pathogens. We discovered a pathology affecting the ovaries, characterized by a yellow discoloration concentrated in the apex of the ovaries resulting from degenerative lesions in the follicles. In extreme cases, marked by intense discoloration, the majority of the ovarioles were affected and these cases were universally associated with egg-laying deficiencies in the queens. Microscopic examination of the degenerated follicles showed extensive paracrystal lattices of 30 nm icosahedral viral particles. A cDNA library from degenerated ovaries contained a high frequency of deformed wing virus (DWV) and Varroa destructor virus 1 (VDV-1) sequences, two common and closely related honeybee Iflaviruses. These could also be identified by in situ hybridization in various parts of the ovary. A large-scale survey for 10 distinct honeybee viruses showed that DWV and VDV-1 were by far the most prevalent honeybee viruses in queen populations, with distinctly higher prevalence in mated queens (100% and 67%, respectively for DWV and VDV-1) than in virgin queens (37% and 0%, respectively). Since very high viral titres could be recorded in the ovaries and abdomens of both functional and deficient queens, no significant correlation could be made between viral titre and ovarian degeneration or egg-laying deficiency among the wider population of queens. Although our data suggest that DWV and VDV-1 have a role in extreme cases of ovarian degeneration, infection of the ovaries by these viruses does not necessarily result in ovarian degeneration, even at high titres, and additional factors are likely to be involved in this pathology.
Analysis of Virion Structural Components Reveals Vestiges of the Ancestral Ichnovirus Genome
Anne-Nathalie Volkoff ,Véronique Jouan,Serge Urbach,Sylvie Samain,Max Bergoin,Patrick Wincker,Edith Demettre,Fran?ois Cousserans,Bertille Provost,Fasseli Coulibaly,Fabrice Legeai,Catherine Béliveau,Michel Cusson,Gabor Gyapay,Jean-Michel Drezen
PLOS Pathogens , 2010, DOI: 10.1371/journal.ppat.1000923
Abstract: Many thousands of endoparasitic wasp species are known to inject polydnavirus (PDV) particles into their caterpillar host during oviposition, causing immune and developmental dysfunctions that benefit the wasp larva. PDVs associated with braconid and ichneumonid wasps, bracoviruses and ichnoviruses respectively, both deliver multiple circular dsDNA molecules to the caterpillar. These molecules contain virulence genes but lack core genes typically involved in particle production. This is not completely unexpected given that no PDV replication takes place in the caterpillar. Particle production is confined to the wasp ovary where viral DNAs are generated from proviral copies maintained within the wasp genome. We recently showed that the genes involved in bracovirus particle production reside within the wasp genome and are related to nudiviruses. In the present work we characterized genes involved in ichnovirus particle production by analyzing the components of purified Hyposoter didymator Ichnovirus particles by LC-MS/MS and studying their organization in the wasp genome. Their products are conserved among ichnovirus-associated wasps and constitute a specific set of proteins in the virosphere. Strikingly, these genes are clustered in specialized regions of the wasp genome which are amplified along with proviral DNA during virus particle replication, but are not packaged in the particles. Clearly our results show that ichnoviruses and bracoviruses particles originated from different viral entities, thus providing an example of convergent evolution where two groups of wasps have independently domesticated viruses to deliver genes into their hosts.
The Modernisation of Manipulative Therapy  [PDF]
Max Zusman
International Journal of Clinical Medicine (IJCM) , 2011, DOI: 10.4236/ijcm.2011.25110
Abstract: Research indicates that, despite physiotherapists’ comprehensive training in the basic sciences, manipulative (currently “musculoskeletal”) therapy is still dominated in the clinical setting by its original, now obsolete, structure-based “biomedical” model. This is further inexplicable in the light of evidence that not only the underlying “philosophy” but also several of the fundamental requirements of the clinical process itself which has the structural-mechanical model as its basis, have been shown to be flawed or at least irrelevant. The apparent inability of the profession to fully abandon outmoded “concepts” (and embrace the acknowledged science-based “best practice” biopsychosocial model) may have potentially undesirable consequences for both patients and therapists engaged in the management of (chronic) musculoskeletal pain and disability.
On the Existence of Subharmonic Screech in Choked Circular Jets from a Sharp-Edged Orifice  [PDF]
Max Kandula
Open Journal of Acoustics (OJA) , 2014, DOI: 10.4236/oja.2014.41003
Abstract: Experiments are performed in choked circular hot and cold nitrogen jets issuing from a 2.44 cm diameter sharp-edged orifice at a fully expanded jet Mach number of 1.85 in an effort to investigate the character of screech phenomenon. The stagnation temperature of the cold and the hot jets are 299 K and 319 K respectively. The axial distribution of the centerline Mach number was obtained with a pitot tube, while the screech data (frequency and amplitude) at different axial and radial stations were measured with the aid of microphones. The fundamental screech frequency of the hot jet is slightly increased relative to that of the cold jet. It is concluded that temperature effects on the screech amplitude are manifested with regard to the fundamental and the subharmonic even at relatively small temperature range considered.
Super-Diffusive Noise Source in Asset Dynamics  [PDF]
Max-Olivier Hongler
Journal of Mathematical Finance (JMF) , 2013, DOI: 10.4236/jmf.2013.31004
Abstract:

Given an asset with value St, we revisit the Black and Scholes dynamics \"\" when the driving noise ξt is a non-Gaussian super-diffusive stochastic process with variance of the type \"\". This super-diffusive quadratic variance behavior, synthesizes a ballistic component which would occur in strongly fluctuating environments. When \"\", the assets can, with high probability, be driven towards the bankruptcy . This extra dynamic feature significantly affects the management of an optimal portfolio. In this context, we focus on basic decisions like: 1) determine the optimal level to sell the asset; 2) determine how to balance a portfolio which incorporates such a high volatility asset; and 3) when facing incertitudes on the assets growth rate μ, construct an optimal adaptive portfolio control. In all mentioned cases and despite the presence of this highly non-Gaussian noise source, we are able to deliver simple exact and fully explicit optimal control rules.

 

A Theoretical Basis for the Scaling Law of Broadband Shock Noise Intensity in Supersonic Jets
Max Kandula
Advances in Acoustics and Vibration , 2011, DOI: 10.1155/2011/573209
Abstract: A theoretical basis for the scaling of broadband shock noise intensity in supersonic jets was formulated considering linear shock-shear wave interaction. Modeling of broadband shock noise with the aid of shock-turbulence interaction with special reference to linear theories is briefly reviewed. A hypothesis has been postulated that the peak angle of incidence (closer to the critical angle) for the shear wave primarily governs the generation of sound in the interaction process with the noise generation contribution from off-peak incident angles being relatively unimportant. The proposed hypothesis satisfactorily explains the well-known scaling law for the broadband shock-associated noise in supersonic jets.
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