Large Inclusion Bodies Research Articles

Fowl Aviadenovirus (FAdV-11) as the causative agent of a vertical outbreak of inclusion body hepatitis in commercial broiler breeders in Brazil

Inclusion body hepatitis (IBH), caused by Fowl Aviadenovirus (FAdV), is a significant disease affecting chickens worldwide. FAdV-11 associated with IBH was identified in 9-day-old commercial broiler breeders in Brazil. The chicks exhibited a sudden increase in daily mortality, accompanied by nonspecific clinical signs, in one house on the farm. The cumulative mortality rate reached 11.13 % by 15 days of age. Macroscopically, the liver was markedly enlarged and pale red with a distinct lobular pattern. Histologically, the liver showed mild to severe multifocal coalescent vacuolar degeneration and necrosis, with hepatocyte nuclei diffusely enlarged and containing large basophilic inclusion bodies. Additionally, the heart exhibited a diffuse, moderate infiltration of lymphocytes and plasma cells, with focal thrombosis in the epicardium. FAdV was detected in liver samples using specific primers for the hexon gene (52 K-fw and 52 K-rv) in a polymerase chain reaction (PCR) assay. Sequencing of the hypervariable region of this gene (Hex L1) for phylogenetic analysis revealed FAdV-D species serotype 11. To our knowledge, this is the first report of FAdV-D serotype 11 as the causative agent of a vertical outbreak of inclusion body hepatitis in broiler breeders in Brazil.

Clinicopathological Investigations Among Recurrent Camelpox Outbreaks in Omanis’ Arabian Camels (Camelus dromedarius)

Camelpox remains a widespread viral disease in camelids, with socioeconomic relevance. The present study explored the hematological, biochemical, and histopathological alterations in dromedary-racing camels from the North of Oman infected with camelpox virus diagnosed by real-time PCR. Blood and skin samples were collected from camels with clinical signs and skin lesions (n=4) and from healthy camels (n=3) from 10 different camel herds. The results indicated that the infected camels showed clinical signs, including pyrexia, lacrimation, nasal mucus discharge, affixed and swollen eyelids, emaciation, and pimples on the skin of the head, legs, and abdomen. Hemoglobin, hematocrit, and platelets were significantly greater, with a significant reduction in leukocyte and lymphocyte counts in infected camels than in healthy camels. Infected camels had higher CK and creatinine levels and hepatic-related metabolites, including AST, ALP, AST, GGT, and LDH, than the apparently healthy camels. Histopathological examination of skin scab samples revealed ballooning degeneration of epidermal cells in the presence of typical large eosinophilic intracytoplasmic inclusion bodies and suppurative dermatitis following secondary bacterial infection in all examined infected camels. Camelpox viral DNA was detected using real-time PCR in the blood and skin samples of all infected camels. These findings in dromedary-racing camels associated with a molecular diagnosis of camelpox are described for the first time in the Sultanate of Oman. Therefore, further studies are warranted.

Neurodegenerative disease-associated inclusion bodies are cleared by selective autophagy in budding yeast.

Protein misfolding, aggregation, and accumulation cause neurodegenerative disorders. One such disorder, Huntington's disease, is caused by an increased number of glutamine-encoding trinucleotide repeats CAG in the first exon of the huntingtin (HTT) gene. Mutant proteins of Htt exon 1 with polyglutamine expansion are prone to aggregation and form pathological inclusion bodies in neurons. Extensive studies have shown that misfolded proteins are cleared by the ubiquitin-proteasome system or autophagy to alleviate their cytotoxicity. Misfolded proteins can form small soluble aggregates or large insoluble inclusion bodies. Previous works have elucidated the role of autophagy in the clearance of misfolded protein aggregates, but autophagic clearance of inclusion bodies remains poorly characterized. Here we use mutant Htt exon 1 with 103 polyglutamine (Htt103QP) as a model substrate to study the autophagic clearance of inclusion bodies in budding yeast. We found that the core autophagy-related proteins were required for Htt103QP inclusion body autophagy. Moreover, our evidence indicates that the autophagy of Htt103QP inclusion bodies is selective. Interestingly, Cue5/Tollip, a known autophagy receptor for aggrephagy, is dispensable for this inclusion body autophagy. From the known selective autophagy receptors in budding yeast, we identified three that are essential for inclusion body autophagy. Amyloid beta peptide (Aβ42) is a major component of amyloid plaques found in Alzheimer's disease brains. Interestingly, a similar selective autophagy pathway contributes to the clearance of Aβ42 inclusion bodies in budding yeast. Therefore, our results reveal a novel autophagic pathway specific for inclusion bodies associated with neurodegenerative diseases, which we have termed IBophagy.

Inclusion Body Hepatitis in commercial broiler chickens of an organised poultry farm – A case study

Adenoviruses cause a wide range of diseases among all avian species. Even though most of them cause mild disease, some are associated with specific clinical conditions. Fowl adenoviruses (FAdVs) are the etiological agents of two important diseases; Inclusion body hepatitis (IBH) and Hepatitis hydropericardium syndrome (HHS) in poultry. Ten dead birds of 45 days old were brought for necropsy to the post-mortem facility available at the Division of Pathology, ICAR-IVRI, Izatnagar. The percentage of mortality was nearly 15 per cent and affected birds were dull, depressed with pallor of comb and ruffled feathers. On post-mortem examination, it was observed that the liver was swollen and yellow with fibrinous deposits over the surface. On microscopic examination, large basophilic intranuclear inclusion bodies were present in hepatocytes which was suggestive of IBH. Diagnosis was further confirmed by Polymerase Chain Reaction (PCR).

Pathogenicity Assessment and Vaccine Efficacy of Fowl Adenovirus Serotype 4 and 11 Responsible for Inclusion Body Hepatitis Hydropericardium Syndrome in Broilers

Thisstudy aimed to assess the pathogenicity and vaccine efficacy of fowl adenovirus serotypes 4 and 11, causing inclusion body hepatitis hydropericardium syndrome in broilers. The study was carried out on 144-day-old Cobb broiler chicks divided into six experimental groups, each of 24 birds. Group, I birds served as a control without any vaccine or viral challenge, while birds of Group II were vaccinated with commercial vaccine on 6th day. Group III and IV birds were non-vaccinated and challenged with 107 TCID50 of FAdV serotype 4 and 11, respectively, on the 27th day. In contrast, Group V and VI birds were vaccinated on the 6th day and challenged with 107 TCID50 of FAdV serotype 4 and 11 on the 27th day. The challenge of FAdV serotype 4 led to 66.66% mortality, and serotype 11 produced 5.00% mortality in the experimental groups. The challenge of the virus led to the production of clinical signs such as depression, huddling, reduced feed intake, reluctance to move, and terminal gasping before death. Characteristic gross lesions of IBH-HPS were observed in birds that died after the challenge of serotypes 4 and 11 of FAdV. The liver was enlarged with focal areas of necrosis, subcapsular hemorrhages, and mild fatty changes. The heart was flabby, congested, and showed hydropericardium with an accumulation of clear watery to a yellow jelly-like fluid in the pericardial sac. The kidneys were enlarged and hemorrhagic. On microscopic examination, the liver showed multifocal areas of necrosis with infiltration of mononuclear cells, mild fatty changes and large basophilic intranuclear inclusion bodies. The birds that died after the challenge of the virus were positive for the presence of FAdV upon PCR. The vaccine efficacy study indicated that the vaccine provided satisfactory protection against Fowl Adenovirus challenge in experimental groups V and VI.

Case Series of Disseminated Xanthogranulomatosis in Red-crowned Parakeets (Cyanoramphus novaezelandiae) with Detection of Psittacine Adenovirus 2 (PsAdV-2).

Simple SummaryLipometabolic disorders, such as xanthogranulomatosis, are common diseases in avian medicine. Various manifestations of lipometabolic disorders and risk factors for acquiring lipometabolic diseases have been described in the past years. Xanthogranulomas are usually limited to the skin and supposed to be associated with traumatic or inflammatory injuries in that area. Disseminated xanthogranulomatosis, appearing simultaneously in several internal organs, has been recently described in psittacine birds, the cause of the diseases was not known. Here, we describe a case series of disseminated xanthogranulomatosis in another psittacine species, the Red-crowned Parakeet (Cyanoramphus novaezelandiae) and a possible association with a concurrent psittacine adenovirus 2 (PsAdV-2) infection. Viral infections that trigger lipometabolic diseases have been described in human medicine in some species of small animals and in chickens. PsAdV-2- infections are widely distributed in avian species. A possible association between PsAdV-2- infections and lipometabolic diseases in the Red-crowned Parakeet should be considered. Individual birds and flocks with both or either of these diseases should be carefully examined and monitored.Xanthogranulomatosis is a common dermatological disease in birds. This form of inflammation, possibly associated with lipometabolic disorders, can also be seen in visceral organs, which as yet has only rarely been described in avian medicine. In general, diseases related to impaired lipid metabolism are frequently reported in avian medicine, with hepatic steatosis and atherosclerosis being the most common. In human medicine, infectious agents—especially some strains of adenovirus—were implicated in contributing to lipometabolic disorders; this has also been described for chicken. Here, a case series of six Red-crowned Parakeets (Cyanoramphus novaezelandiae) is presented, all cases being characterized by psittacine adenovirus 2 (PsAdV-2) infection with or without disseminated xanthogranulomatosis. The affected individuals were examined alive by clinical examination. Total body radiographs were taken of two birds, haematology and blood biochemistry results were achieved in one bird. The birds either died immediately after clinical presentation or within two days, two individuals were euthanized due to worsening of their clinical condition. All birds underwent a post-mortem examination. While four birds were finally diagnosed with disseminated xanthogranulomatosis, all six individuals had large eosinophilic intranuclear inclusion bodies in the epithelial cells of the collecting ducts of the kidney and tested positive for PsAdV-2. Further examinations are needed to clarify to what extent PsAdV-2 might elicit lipometabolic disease in birds, or psittacines in general, and, in particular, the Red-crowned Parakeet.

The Cytotoxicity and Clearance of Mutant Huntingtin and Other Misfolded Proteins.

Protein misfolding and aggregation are implicated in many neurodegenerative diseases. One of these diseases is Huntington’s, which is caused by increased glutamine-encoding trinucleotide repeats within the Huntingtin gene. Like other misfolded proteins, mutated Huntingtin proteins with polyglutamine expansions are prone to aggregation. Misfolded proteins exist as soluble monomers, small aggregates, or as large insoluble inclusion bodies. Misfolded protein aggregates are believed to be cytotoxic by stressing the protein degradation machinery, disrupting membrane structure, or sequestering other proteins. We recently showed that expression of misfolded proteins lowers cellular free ubiquitin levels, which compromises the protein degradation machinery. Therefore, the efficient degradation of misfolded proteins is critical to preserve cell health. Cells employ two major mechanisms to degrade misfolded proteins. The first is the ubiquitin-proteasome system (UPS), which ubiquitinates and degrades misfolded proteins with the assistance of segregase Cdc48/p97. The UPS pathway is mainly responsible for the clearance of misfolded proteins present as monomers or smaller aggregates. The second pathway is macroautophagy/autophagy, in which protein aggregates or inclusion bodies are recruited into an autophagosome before transport to the vacuole/lysosome for degradation. This review is focused on the current understanding of the cytotoxicity of misfolded proteins as well as their clearance pathways, with a particular emphasis on mutant Huntingtin.

Isolation of Lumpy Skin Disease Virus Isolated from SPPV Vaccinated Cattle

Massive outbreaks of suspected LSDV in cattle population were observed during 2017 and 2018 at Beni-Suef governorate. Samples from diseased cattle, previously SPPV vaccinated with SPPV, were inoculated in embryonated chicken eggs (ECE) using chorio-allantoic membrane (CAM) route. Histopathological examination of the inoculated CAMs showed large eosinophilic intracytoplasmic inclusion bodies characteristic for LSDV. The inoculated CAMs were hemorrhagic with congestion blood vessels appeared by the 1st passage then become more pronounced after the second - fourth passages. Characteristic pock lesions were observed after the 1st passage and become clear after the third passage and become clearly observed 4 days post inoculation. For molecular identification, DNA was extracted from a pool of the infected CAMs. Two pairs of primers specific for LSDV including one flanking a 554 bp product of the G gene and second flanking 172 of the RP030 gene were used. In conclusion, LSDV infections have been detected and the virus has been isolated and identified by PCR from cattle previously vaccinated with SPPV vaccine during the summer of 2018.

IDENTIFICATION AND CORRELATION OF A NOVEL SIADENOVIRUS IN A FLOCK OF BUDGERIGARS (MELOPSITTACUS UNDULATES) INFECTED WITH SALMONELLA TYPHIMURIUM IN THE UNITED STATES.

A flock of budgerigars (Melopsittacus undulates) was purchased from a licensed breeder and quarantined at a zoologic facility within the United States in 2016. Following 82 deaths within the flock, the remaining 66 birds were depopulated because of ongoing clinical salmonellosis despite treatment. Gross necropsy was performed on all 66 birds. Histopathologic examination was performed on 10 birds identified with gross lesions and 10 birds without. Pathologic findings were most often observed in the liver, kidney, and spleen. Lesions noted in the livers and spleens were consistent with published reports of salmonellosis in psittacine species. Multisystemic changes associated with septicemia were not noted, most likely because of antibiotic intervention before euthanasia. Of the 20 budgerigars evaluated by histopathology, six had large basophilic intranuclear inclusion bodies within tubular epithelia in a portion of the kidneys. Electronic microscopy, next-generation sequencing, Sanger sequencing, and phylogenetic analyses were used to identify and categorize the identified virus as a novel siadenovirus strain BuAdV-1 USA-IA43444-2016. The strain was 99% similar to budgerigar adenovirus 1 (BuAdV-1), previously reported in Japan, and to a psittacine adenovirus 5 recently identified in a U.S. cockatiel. Salmonella typhimurium carriers were identified via polymerase chain reaction (PCR) and bacterial culture and compared with viral carriers identified via PCR. Inclusion bodies and Salmonella detection were significant in birds with gross lesions versus those without; however, there was no correlation between budgerigars positive with siadenovirus by PCR and concurrent Salmonella infection. Identifying subclinical siadenovirus strain BuAdV-1 USA-IA43444-2016 infection in this flock significantly differs from a previous report of clinical illness in five budgerigars resulting in death caused by BuAdV-1 in Japan. S. typhimurium remains a significant pathogen in budgerigars, and zoonotic concerns prompted depopulation to mitigate the public health risks of this flock.

Cauliflower mosaic virus P6 inclusion body formation: A dynamic and intricate process

During an infection, Cauliflower mosaic virus (CaMV) forms inclusion bodies (IBs) mainly composed of viral protein P6, where viral activities occur. Because viral processes occur in IBs, understanding the mechanisms by which they are formed is crucial. FL-P6 expressed in N. benthamiana leaves formed IBs of a variety of shapes and sizes. Small IBs were dynamic, undergoing fusion/dissociation events. Co-expression of actin-binding polypeptides with FL-P6 altered IB size distribution and inhibited movement. This suggests that IB movement is required for fusion and growth. A P6 deletion mutant was discovered that formed a single large IB per cell, which suggests it exhibited altered fusion/dissociation dynamics. Myosin-inhibiting drugs did not affect small IB movement, while those inhibiting actin polymerization did. Large IBs colocalized with components of the aggresome pathway, while small ones generally did not. This suggests a possible involvement of the aggresome pathway in large IB formation.

Effect of chemically defined growth medium components on characteristics of bacterial inclusion bodies

AbstractBACKGROUNDInactive aggregated protein deposits formed during fermentation of recombinant bacteria – inclusion bodies (IBs) – continue to be a significant source of active proteins. Understanding how the microenvironment, in particular growth medium, affects the quality and quantity of the IBs would be desirable for optimal production of proteins. In this study, we explore the effect of various chemically defined media components on IBs using a variety of analytical techniques. Expression of a biotherapeutic, ranibizumab, has been chosen as a case study.RESULTSA repertoire of nutrients, including but not limited to carbon and nitrogen source, vitamins, cofactors, buffering agents and minerals, were examined. Sucrose, biotin, pantothenate, glutathione, K2HPO4, K2SO4, cyanocobalamin and CaSO4 were shortlisted based on experimentation. A design of experiments (DOE) study was performed to identify optimal concentrations of and interactions between these nutrients. Higher concentrations of sucrose, biotin and pantothenate, and lower concentrations of cyanocobalamin, CaSO4 and glutathione, resulted in larger IBs and greater product expression. Further, K2HPO4 and K2SO4 concentrations did not seem to have a meaningful impact on product formation.CONCLUSIONSMedium composition affects size and quality of IBs. The size of IBs exhibits a positive correlation with the quantity of product expressed, as well as the purity of the product, but does not correlate with the total amount of host cell proteins produced. IB size could be used as a key process attribute during bioreactor optimization, and the otherwise difficult task of measuring product concentration in the fermentation broth could be avoided. © 2020 Society of Chemical Industry

Aggregation State of Huntingtin Regulates Its Interaction with Lipid Membranes

Huntingtin disease (HD) is a neurodegenerative disease caused by an expansion of a polyglutamine (polyQ) tract within the huntingtin (htt) protein. There is a critical threshold for the polyQ length, which once exceeded, causes HD. PolyQ expansion promotes the self-assembly of htt into a variety of aggregate species ranging from small oligomers to large fibrils that eventually incorporate into large inclusion bodies. The first 17 amino acids of htt (Nt17), which directly precede the polyQ tract, play a role in initiating aggregation by facilitating the formation of oligomeric intermediates that lead to fibril formation. Nt17 also functions as a lipid membrane binding domain. To characterize the ability of different aggregate forms of htt to bind lipid membranes, htt was pre-aggregated, and the ability of different aggregate states to bind lipid membranes was determined by a polydiacetylene lipid binding assay. The aggregation state of htt was verified by atomic force microscopy (AFM). While monomeric htt readily bound lipid vesicles, the interaction was enhanced by the presence of htt oligomers. To determine if the ability of oligomers to continue to aggregate on the lipid surface played a role, htt oligomers were stabilized via a lysine cross-linker, eliminating its ability to further aggregate. Cross-linked oligomers were assessed and characterized by ThT assays, filter traps, AFM, and dynamic light scattering. The ability of the cross-linked oligomers to interact with lipid membranes was then assessed using PDA assays and AFM.

Articles of Significant Interest in This Issue

Unique peptide sequences often direct protein localization to specific cellular sites. However, on-site translation of mRNAs also provides an efficient means of subcellular protein localization. Katsafanas and Moss (e01671-19) found that on-site translation occurred for the poxvirus mRNA that encodes the 150-kDa A-type inclusion (ATI) protein, which forms large inclusion bodies that sequester viral particles. Nascent peptides anchored ATI mRNA at the inclusions, permitting multiple rounds of translation and thereby preventing premature protein aggregation and trapping of virions at transcription sites. These findings shed light on the coordination of transcription, translation, and virion assembly during the poxvirus life cycle.

Wnt5a Belongs to the Lysosomal Cholesterol-Sensing Machinery that Controls mTORC1

The Wnt ligand, Wnt5a limits cellular cholesterol accumulation, however, it role in atherosclerosis is unknown. Here, we show that mice deleted for Wnt5a in vascular smooth muscle cells (VSMCs) developed atherosclerosis lesions when fed a cholesterol-rich diet. VSMCs accumulated cholesterol in enlarged endosome/lysosome (LELs), and lipofuscin containing vesicles. We identified Wnt5a, as a member of the nutrient/energy/stress sensor, mTORC1 scaffolding complex, which drives lysosomal fonction and promotes cholesterol trafficking. By decreasing mTORC1 activity, Wnt5a senses changes in dietary cholesterol supply, promotes LELs cholesterol egress to the endoplasmic reticulum (ER), and protects against atherosclerosis. Moreover, Wnt5a binds cholesterol-rich membranes and interacts with the polytopic membrane-bound Niemann–Pick C1 (NPC1) and soluble Niemann–Pick C2 (NPC2), two lysosomal proteins that regulate cholesterol export from LELs. Consequently, absence of Wnt5a decoupled mTORC1 from variations in LELs sterol levels, and this resulted in accumulation of large intracellular inclusion bodies, large LELs, decreased cholesterol content in the ER, activation of the sterol regulatory element-binding protein-2 (SREBP-2) a master regulator of cholesterol biosynthesis. These results reveal an unexpected function of the Wnt5a pathway, and provide a conceptually new basis for future drug development to prevent cholesterol accumulation, atherosclerosis, and lysosomal storage diseases.

Novel siadenovirus infection in a cockatiel with chronic liver disease

A 15-year-old female cockatiel (Nymphicus hollandicus) undergoing long term management for hepatopathy died and underwent necropsy. Microscopic findings were consistent with chronic liver disease characterized by distorted hepatic architecture, fibrosis and biliary proliferation. The additional finding of large intranuclear inclusion bodies within hepatocytes and renal tubular epithelium prompted diagnostic next generation sequencing. The assembled sequences isolated from pooled kidney and liver were related to siadenoviruses. The genus Siadenovirus, within the family Adenoviridae, includes several species of viruses that pathogenically infect avian species including hemorrhagic enteritis virus of turkeys and marble spleen virus of pheasants. Siadenoviruses have previously been reported in seven psittacine species: a plum-headed parakeet (Psittacula cyanocephala), an umbrella cockatoo (Cacatua alba) budgerigars (Melopsittacus undulates), an eastern rosella (Platycercus eximius), a scarlet chested parrot (Neophema splendida), a cockatiel (Nymphicus hollandicus), and a red-crowned parakeet (Cyanoramphus novaezelandiae). This report describes a novel siadenovirus in a cockatiel that is highly identical to budgerigar adenovirus 1 and distinct from PsAdV-2 in cockatiels. We report the clinical pathologic, gross, and histopathologic findings in a cockatiel with chronic hepatitis and a novel siadenovirus, PsAdV-5. The sequencing data is presented with a phylogenetic analysis.

Chlamydia trachomatis Growth and Cytokine mRNA Response in a Prostate Cancer Cell Line.

In the present paper, we report that C. trachomatis can be efficiently propagated and affect mRNA expression for two major cytokines, relevant to tumor progression, in CWR-R1 cells, a malignant prostate cell line. CWR-R1 and McCoy cells, a classic cell line for chlamydial research, were grown and infected with C. trachomatis under similar conditions. Cell monolayers were harvested for RNA analysis and immunostaining with major outer membrane protein (MOMP) antibody at 24, 48, and 72 hours of the postinfection (hpi) period. It was shown that the infectious cycle of chlamydial pathogen in CWR-R1 cells resembles the progression of C. trachomatis infection in McCoy cells but with a few important differences. First of all, the initial stage of C. trachomatis propagation in CWR-R1 cells (24 hpi) was characterized by larger inclusion bodies and more intense, specific immunofluorescent staining of infected cells as compared with McCoy cells. Moreover, there was a corresponding increase in infective progeny formation in CWR-R1 cells along with mRNA for EUO, a crucial gene controlling the early phase of the chlamydial development cycle (24 hpi). These changes were more minimal and became statistically insignificant at a later time point in the infectious cycle (48 hpi). Altogether, these data suggest that the early phase of C. trachomatis infection in CWR-R1 cells is accompanied by more efficient propagation of the pathogen as compared with the growth of C. trachomatis in McCoy cells. Furthermore, propagation of C. trachomatis in CWR-R1 cells leads to enhanced transcription of interleukin-6 and fibroblast growth factor-2, genes encoding two important proinflammatory cytokines implicated in the molecular mechanisms of chemoresistance of prostate cancer and its ability to metastasize. The possible roles of reactive oxygen species and impaired mitochondrial oxidation in the prostate cancer cell line are discussed as factors promoting the early stages of C. trachomatis growth in CWR-R1 cells.

Respiratory syncytial virus.

Respiratory syncytial virus (RSV) is the most common cause of infant hospitalization and causes a high burden of disease in the elderly, too. This enveloped negative-stranded RNA virus has been recently reclassified in the Pneumoviridae family. Infections of the respiratory cells happens when the two major surface glycoproteins, G and F, take contact with the cell receptor CX3CR1 and mediate entry by fusion, respectively. Viral mRNA transcription, genomic RNA synthesis and nucleocapsid formation occur in large cytoplasmic inclusion bodies to avoid recognition by the host innate immune response. Most progeny virions remain associated to the infected cell surface; fusion of infected with adjacent cells results in the formation of large multinucleated syncytia that eventually undergo apoptosis. Desquamated epithelial cells form the plugs that with mucus and fibrin may cause lower airway obstructions. Pathogenetic mechanism of severe RSV disease likely involve both the extent of viral replication and the host immune response. Regarding the latter, single nucleotide polymorphism analysis and genome-wide association studies showed that genetic susceptibility to severe RSV infection is likely a complex trait, in which many different host genetic variants contribute. Recent studies pointed to the fact that bronchiolitis severity depends more on the specific infecting RSV genotypes than on the amount of viral loads. A population-based surveillance system to better define RSV burden of disease would be of valuable help for implementing future vaccination programs.

Microscopic and Molecular Evidence of the First Elasmobranch Adomavirus, the Cause of Skin Disease in a Giant Guitarfish, Rhynchobatus djiddensis.

ABSTRACTOnly eight families of double-stranded DNA (dsDNA) viruses are known to infect vertebrate animals. During an investigation of papillomatous skin disease in an elasmobranch species, the giant guitarfish (Rhynchobatus djiddensis), a novel virus, distinct from all known viral families in regard to particle size, morphology, genome organization, and helicase phylogeny was discovered. Large inclusion bodies containing 75-nm icosahedral viral particles were present within epithelial cell nuclei in the proliferative skin lesions. Deep metagenomic sequencing revealed a 22-kb circular dsDNA viral genome, tentatively named guitarfish “adomavirus” (GAdoV), with only distant homology to two other fish viruses, Japanese eel endothelial cell-infecting virus (JEECV) and a recently reported marbled eel virus. Phylogenetic analysis of the helicase domain places the guitarfish virus in a novel clade that is equidistant between members of the Papillomaviridae and Polyomaviridae families. Specific PCR, quantitative PCR, and in situ hybridization were used to detect, quantify, and confirm that GAdoV DNA was localized to affected epithelial cell nuclei. Changes in the viral titer, as well as the presence of a hybridization signal, coincided with the progression and then final resolution of gross and microscopic lesions. The results indicate that GAdoV is the causative agent of the proliferative skin lesions.

Rat polyomavirus 2 infection in a colony of X-linked severe combined immunodeficiency rats in Japan.

Polyomaviruses (PyVs) infect a wide range of animals and provoke wasting diseases, particularly in immunosuppressed hosts. Recently, a novel Rattus norvegicus polyomavirus 2 (RatPyV2) has been identified in a colony of X-linked severe combined immunodeficiency (X-SCID) rats in the United States. Here, we describe the first report of the RatPyV2 infection in an X-SCID rat colony in Japan. The affected rats exhibited adult-onset wasting. Histologically, we observed large basophilic intranuclear inclusion bodies within the hyperplastic or dysplastic epithelial cells in the salivary glands, Harderian glands, extraorbital lacrimal glands, and in respiratory and reproductive tissues. Among these organs, the parotid salivary, Harderian, and extraorbital lacrimal glands were most obviously affected. In particular, the parotid salivary glands were the most severely and diffusely affected and atrophic lesions were prominent even at 1 month of age, which suggested that the parotid salivary glands would be highly susceptible to RatPyV2 in X-SCID rats. RatPyV2 inclusion bodies were also detected in the tail of the epididymis and deferent duct. Such reproductive lesions developed significantly in the later stage of breeding age, and therefore may be associated with the reduced fecundity observed in the infected X-SCID rats. We also established a simple, rapid, and non-invasive diagnostic method based on the Amp-FTA method, using buccal swabs for the detection of RatPyV2 in immunodeficient rats. Our findings contribute to the early detection and diagnosis of RatPyV2 infections.

PolyQ caught in the act?

Cell Biology Huntington's disease is a neurodegenerative disorder caused by the expanded polyglutamine (polyQ) repeat of mutant huntingtin (mHtt). PolyQ expansions result in protein aggregation into large neuronal inclusion bodies (IBs). These IBs are often regarded as protective deposits of toxic soluble species. Bauerlein et al. used cryo-electron tomography to analyze the structure of mHtt IBs in mammalian cells and neurons under close-to-native conditions and at molecular resolution. The mHtt IBs consisted of radially arranged fibrils that closely interacted with cellular endomembranes, particularly the endoplasmic reticulum (ER). The interaction appeared to alter ER function and membrane dynamics at the IB periphery. Thus, rather than being inert deposits, mHtt IBs may mediate aspects of polyQ pathology. Cell 171 , 179 (2017).