Progression of histomonosis in commercial chickens following experimental infection with an in vitro propagated clonal culture of Histomonas meleagridis

Four commercial strains of chickens, namely, ISA brown leghorn (ISA), TETRA-SL brown (TETRA-SL), Lohmann brown (LB), and Lohmann LSL (LSL), were infected with a well-defined clonal culture of Histomonas meleagridis (H. meleagridis/Turkey/Austria/2922-C6/04) to investigate their susceptibility to histomonosis. Each group included 16 chickens, which were housed under the same conditions in separate pens. All chickens were infected with 10(4) histomonads orally and intracloacally at 14 days of age. No mortality or clinical signs were observed during the experiment in all birds. Three birds of each chicken strain were euthanatized on days 4, 7, 10, 14, and 21 postinfection. Incidence of histomonosis on the basis of cecal lesions was found to be 64.00% in TETRA-SL, 62.50% in LB, 53.12% in LSL, and 43.75% in ISA chickens. Fewer lesions were noticed in livers than in ceca, with an incidence of 15.62% in TETRA-SL, 9.37% in LB, and 3.12% in ISA chickens. No liver lesions were found in the LSL chickens. Statistical analysis revealed that there was no significant difference (P > 0.05) in susceptibility to experimental H. meleagridis infection based on cecal and liver involvement. Polymerase chain reaction (PCR) and immunohistochemistry were found to be reliable tools to confirm the presence of histomonads and changes in the ceca. However, some negative PCR results were recorded from the livers despite the presence of macroscopic lesions. Additionally, DNA of H. meleagridis was detected by PCR in a few of the lungs, but immunohistochemistry was negative. Nucleic acid of the protozoan parasite was not detected in samples from kidney, brain, spleen, or bursa of Fabricius. Altogether, the high susceptibility of commercial chicken lines to histomonosis could be demonstrated and characterized by severe lesions in the ceca and insignificant involvement of the liver, approaching a maximum on days 7-14 postinfection.

Metagenomic discovery of biomass-degrading genes and genomes from cow rumen

The paucity of enzymes that efficiently deconstruct plant polysaccharides represents a major bottleneck for industrial-scale conversion of cellulosic biomass into biofuels. Cow rumen microbes specialize in degradation of cellulosic plant material, but most members of this complex community resist cultivation. To characterize biomass-degrading genes and genomes, we sequenced and analyzed 268 gigabases of metagenomic DNA from microbes adherent to plant fiber incubated in cow rumen. From these data, we identified 27,755 putative carbohydrate-active genes and expressed 90 candidate proteins, of which 57% were enzymatically active against cellulosic substrates. We also assembled 15 uncultured microbial genomes, which were validated by complementary methods including single-cell genome sequencing. These data sets provide a substantially expanded catalog of genes and genomes participating in the deconstruction of cellulosic biomass.

Seroprevalence of Histomonas meleagridis in pullets and laying hens determined by ELISA

Serum samples from 1120 layers from 56 flocks and 400 pullets from 20 flocks were tested by an indirect sandwich ELISA to investigate the prevalence of antibodies to Histomonas meleagridis in chickens kept in alternative husbandry systems. The overall prevalence of antibodies to H meleagridis in layers was 37.3 per cent, and positive birds were identified in 50 flocks. This was significantly higher than in pullets, where only 8.3 per cent of the birds tested positive. Optical density (OD) values obtained from pullet sera were much lower than the OD values from layers; however, positive birds were detected in half of the pullet flocks. In particular, all birds from an organic pullet flock were found to be positive, with high OD values. Overall, the highest prevalence of positive sera was obtained from birds kept in free-range flocks. Attempts to reisolate live histomonads from birds in 18 layer flocks were unsuccessful.

Enhanced tumor therapy using vaccinia virus strain GLV-1h68 in combination with a β-galactosidase-activatable prodrug seco-analog of duocarmycin SA

Breast cancer is the most common cause of cancer-related death worldwide, thus remaining a crucial health problem among women despite advances in conventional therapy. Therefore, new alternative strategies are needed for effective diagnosis and treatment. One approach is the use of oncolytic viruses for gene-directed enzyme prodrug therapy. Here, the lacZ-carrying vaccinia virus (VACV) strain GLV-1h68 was used in combination with a β-galactosidase-activatable prodrug derived from a seco-analog of the natural antibiotic duocarmycin SA. Tumor cell infection with the VACV strain GLV-1h68 led to production of β-galactosidase, essential for the conversion of the prodrug to the toxic compound. Furthermore, drug-dependent cell kill and induction of the intrinsic apoptosis pathway in tumor cells was also observed on combination therapy using the prodrug and the GLV-1h68 strain, despite the fact that VACV strains encode antiapoptotic proteins. Moreover, GI-101A breast cancer xenografts were effectively treated by the combination therapy. In conclusion, the combination of a β-galactosidase-activatable prodrug with a tumor-specific vaccinica virus strain encoding this enzyme, induced apoptosis in cultures of the human GI-101A breast cancer cells, in which a synergistic oncolytic effect was observed. Moreover, in vivo, additional prodrug treatment had beneficial effects on tumor regression in GLV-1h68-treated GI-101A-xenografted mice.

Experimental infection of turkeys and chickens with a clonal strain of Tetratrichomonas gallinarum induces a latent infection in the absence of clinical signs and lesions

The pathogenicity of a mono-eukaryotic culture of Tetratrichomonas gallinarum in specific pathogen free (SPF) chickens and turkeys was studied. Two experiments of identical design were performed: the first with SPF chickens and the second with commercial turkeys. Each experiment included three groups. Groups 1 and 2 each contained 12 infected and three in-contact birds. The birds in these groups were infected on the first day of life, either cloacally (group 1) or orally (group 2). Group 3 consisted of four control birds. Re-isolation of the parasite from cloacal swabs was performed to verify the excretion of T. gallinarum. The infected birds excreted trichomonads from the second day post-infection. Spread of the flagellate from infected to in-contact birds was detected after 5 days post-infection (dpi), based on the re-isolation of the protozoa. No clinical signs or deaths were recorded in chickens or turkeys. Three birds were killed at 4, 8, 14 and 21dpi and various tissues were collected for pathological examination. No gross lesions were noted. Protozoal DNA was demonstrated in the oesophagus, duodenum, jejunum, caecum, liver, lung, bursa of Fabricius and brain by polymerase chain reaction and in-situ hybridization. No antibodies were detected in the serum of infected birds by enzyme linked immunosorbent assay. Microscopical changes were only present in the caecum, where there was sloughing of the epithelium associated with the presence of numerous flagellates on the epithelial surface, within the crypts of Lieberkühn and in the lamina propria. These changes were found in caecal samples from infected and in-contact birds. These studies have demonstrated the rapid transmission of T. gallinarum between both turkeys and chickens and the establishment of a latent infection in both species.

Phylogenetic analysis of avian hepatitis E virus samples from European and Australian chicken flocks supports the existence of a different genus within the Hepeviridae comprising at least three different genotypes

Using PCRs that amplify regions of helicase and capsid genes, the presence of avian hepatitis E virus (avian HEV) was determined in samples from European and Australian chicken flocks (collected from 2005 to 2007 and 1986 to 1995, respectively). A total of 27 virus samples from 9 countries were analysed to determine the phylogenetic relationship following PCRs and nucleic acid sequencing of the helicase and capsid regions of 18 avian HEV samples. For comparison, helicase and capsid sequences of completely sequenced avian HEVs from Europe, Australia and the USA were used. In addition, available helicase and capsid sequences of other avian HEVs and four mammalian HEVs were included. At least three genotypes within the avian HEV were revealed. These genotypes tend to be differentiated geographically. Altogether, the present investigation is of importance to understand the epidemiology of avian HEV infections in chickens and gives new insight into the phylogenetic relationships between isolates. Furthermore, we would like to propose that avian HEV represent a separate genus within the Hepeviridae consisting of different genotypes.

Experimental infection of chickens with Histomonas meleagridis confirms the presence of antibodies in different parts of the intestine

Specific pathogen-free chickens were infected with a clonal culture of the protozoan parasite, Histomonas meleagridis. Severe lesions were found within the caeca of all birds euthanized at 7 and 14 days post-infection (d.p.i.). Following necropsy of birds, intestinal samples were taken to establish ex vivo tissue cultures to determine the IgG, IgA and IgM antibody levels in the supernatants before and after incubation with a recently established ELISA. Presence of antibodies was also determined in the sera and first optical density values for IgG above the cut-off were detected at 14 d.p.i. IgA levels remained low in the serum with a small peak 4 weeks p.i., a phenomenon also found for IgM. The intestinal tissue samples showed very strong immunological reactions in the parasitized caeca with an initial peak of IgM, high levels of IgG and a continuous increase of IgA. In the duodena and jejuna, IgA values reached similar high levels as those obtained in the caeca, whereas IgG and IgM increased only slightly.

Characterization of Austrian koi herpesvirus samples based on the ORF40 region

Using a PCR that amplifies a region of the thymidine kinase (TK) gene, an epidemic spread of koi herpesvirus (KHV) was determined in koi carps in Austria in 2007. A total of 15 virus samples from different locations in Austria were analyzed to determine their genetic relatedness following PCR and nucleic acid sequencing of the open reading frame 40 (ORF40) region of the KHV genome. ORF40-specific PCR amplification products that were obtained from tissue samples shared 100% nucleotide sequence identity with the published sequence of the Japanese strain of KHV. The ORF40 sequence of one isolate from the UK that was included in the present study was 100% identical with the published sequence of an Israeli strain of KHV. This is the first study that used a larger number of samples and a PCR method, which allowed distinguishing all 3 strains of KHV. The present investigation provides information on the epidemiology of KHV infections in Europe and describes a useful molecular tool for epidemiological studies.

Oral infection of turkeys with in vitro-cultured Histomonas meleagridis results in high mortality

In the present study a well-defined clonal culture of Histomonas meleagridis was used to investigate whether turkeys can be infected orally with in vitro-propagated parasites in the absence of any vector. Therefore, two subsequent experiments were arranged to study the morbidity and mortality of a virulent strain of histomonads in turkeys following crop instillation of protozoa and a feed restriction for 5 h. Soon after infection, the parasites triggered total morbidity and mortality in a group of 14 turkeys, of which 10 birds were orally infected and the others were kept as in-contact birds. Administration of the same number of histomonads into either the cloaca or the crop of individually housed birds was investigated subsequently, to avoid any bird-to-bird transmission. All eight cloacally infected turkeys and six out of eight orally infected turkeys contracted severe histomonosis, with only two birds surviving the infection expressing no clinical signs. During pathological investigations, all birds showed pathognomonic lesions in the livers and caeca indicative for histomonosis, except the two turkeys that survived the infection. The results of the experiments verify for the first time the effective oral infection of 1-day-old turkeys with clonal in vitro-cultured H. meleagridis.

[Quality assurance of a universal newborn hearing screening. Recommendations of the German Society of Phoniatrics and Pediatric Audiology]

Statutory implementation of a universal newborn hearing screening requires a continuous quality assurance monitoring. Therefore, at the Annual Meeting in 2007, the members of the German Society of Phoniatrics and Pediatric Audiology passed a recommendation on measures of quality assurance applied to newborn hearing screening. This recommendation describes the procedures, performance, location, time frame, and technical prerequisites of the screening and of potentially necessary follow-ups, the definition of hearing loss to be detected, the performing and responsible professional groups and their qualifications for the screening, the regulation of repeat and control screenings, the confirmation diagnostics and initiation of therapy, the information of parents, the documentation of screening results, the aims and organization of a tracking system, the tasks of regional screening centers and of a supraregional institution for the quality assurance of the hearing screening, the central collection of person and screening-related quality relevant data, and the accessibility of defined data sets as predisposition for cost analyses and quality reports.

Phylogenetic analysis of spring viraemia of carp virus isolates from Austria indicates the existence of at least two subgroups within genogroup Id

Genetic relationships between 22 spring viraemia of carp virus (SVCV) isolates from Austria collected between 1994 and 2007 were determined based on the partial nucleotide sequence of the glycoprotein gene (G gene). Phylogenetic analyses located all Austrian isolates except one in genogroup Id. One isolate collected in 2007 was placed within the SVCV Ia genogroup. More importantly, the study also revealed 3 distinct clusters within genogroup Id, designated Id1, Id2 and Id3. Existence of subgroups Id2 and Id3 within the genogroup Id was supported by high bootstrap values. The genetic clustering could neither be linked to host species nor to geographic localization of fish farms. Furthermore, no clear link could be established between the pathological lesions and phylogenetic relationship. However, time-dependent division of the isolates was observed. Viruses from the Id1 cluster were mainly sampled in Austria in the 1990s and up until 2003, whereas all viruses from the Id2 subgroup were isolated after 2003.

A perspective: metatranscriptomics as a tool for the discovery of novel biocatalysts

In this mini-review, advantages and current bottlenecks of metatranscriptomic-sequencing for the discovery of novel enzymes for biotechnological applications will be discussed. Comparison of this innovative approach to traditional metagenomic-sequencing will illustrate that expression profiling has a promising future as a direct and very efficient method for the discovery of novel biocatalysts, even from complex microbial communities.