Molecular characterization and virulence gene profiling of pathogenic Streptococcus agalactiae populations from tilapia ( Oreochromis sp.) farms in Thailand

Streptococcus spp. were recovered from diseased tilapia in Thailand during 2009-2010 ( n = 33), and were also continually collected from environmental samples (sediment and water) from tilapia farms for 9 months in 2011 ( n = 25). The relative percent recovery of streptococci from environmental samples was 13-67%. All streptococcal isolates were identified as S. agalactiae (group B streptococci [GBS]) by a species-specific polymerase chain reaction. In molecular characterization assays, 4 genotypic categories comprised of 1) molecular serotypes, 2) the infB allele, 3) virulence gene profiling patterns ( cylE, hylB, scpB, lmb, cspA, dltA, fbsA, fbsB, bibA, gap, and pili backbone-encoded genes), and 4) randomly amplified polymorphic DNA (RAPD) fingerprinting patterns, were used to describe the genotypic diversity of the GBS isolates. There was only 1 isolate identified as molecular serotype III, while the others were serotype Ia. Most GBS serotype Ia isolates had an identical infB allele and virulence gene profiling patterns, but a large diversity was established by RAPD analysis with diversity tending to be geographically dependent. Experimental infection of Nile tilapia ( Oreochromis niloticus) revealed that the GBS serotype III isolate was nonpathogenic in the fish, while all 5 serotype Ia isolates (3 fish and 2 environmental isolates) were pathogenic, with a median lethal dose of 6.25-7.56 log₁₀ colony-forming units. In conclusion, GBS isolates from tilapia farms in Thailand showed a large genetic diversity, which was associated with the geographical origins of the bacteria.

Outbreaks of ulcerative disease associated with ranavirus infection in barcoo grunter, Scortum barcoo (McCulloch & Waite)

In 2013, an outbreak of ulcerative disease associated with ranavirus infection occurred in barcoo grunter, Scortum barcoo (McCulloch & Waite), farms in Thailand. Affected fish exhibited extensive haemorrhage and ulceration on skin and muscle. Microscopically, the widespread haemorrhagic ulceration and necrosis were noted in gill, spleen and kidney with the presence of intracytoplasmic eosinophilic inclusion bodies. When healthy barcoo grunter were experimentally challenged via intraperitoneal and oral modes with homogenized tissue of naturally infected fish, gross and microscopic lesions occurred with a cumulative mortality of 70-90%. Both naturally and experimentally infected fish yielded positive results to the ranavirus-specific PCR. The full-length nucleotide sequences of major capsid protein gene of ranaviral isolates were similar to largemouth bass virus (LMBV) and identical to largemouth bass ulcerative syndrome virus (LBUSV), previously reported in farmed largemouth bass (Micropterus salmoides L.), which also produced lethal ulcerative skin lesions. To the best of our knowledge, this is the first report of a LMBV-like infection associated with skin lesions in barcoo grunter, adding to the known examples of ranavirus infection associated with skin ulceration in fish.

Anthelmintic activity of Rosmarinus officinalis against Dactylogyrus minutus (Monogenea) infections in Cyprinus carpio

Monogenean parasites are important ectoparasites of fish, and are responsible for severe economic impacts in the aquaculture industry. They are usually treated with chemicals, but the chemicals can have harmful side effects in the fish and may pose threats to human health. Rosemary (Rosmarinus officinalis) is a common medicinal herb, with antimicrobial and antitumor properties. Here, we examined the anthelmintic activity of rosemary extract against the monogenean (Dactylogyrus minutus) in vitro and in vivo using bath treatment and oral administration. The in vitro experiments showed that parasite survival was affected by both rosemary extract concentration and the solvent (water and ethanol). Parasites were dead at 61.8±5.6 and 7.8±1.4min when exposed to 100 and 200g aqueous rosemary extract solution/L of water respectively. It took 166.7±48.2 and 5.4±1.01min to kill the parasites when exposed to 1 and 32g ethanol rosemary extract solution/L of water respectively. Moreover, pure component of rosemary extract obtained commercially used in in vitro experiments showed that 1,8-Cineole was the most toxic component of the main components tested. Parasite intensity and prevalence in fish exposed to 50 and 100g aqueous rosemary solution/L water for 30min were significantly lower than they were in controls (p<0.05). In oral treatment experiments, diets of Cyprinus carpio were supplemented with eight different concentrations of aqueous rosemary extract. The intensity of parasites was significantly less in fish fed for 30days with feed containing 60, 80 and 100ml aqueous extract/100g feed than in control (p<0.05). Together these results indicate that rosemary is a promising candidate for prevention and control of monogenean infection.

Successful 5-azacytidine treatment of myeloid sarcoma and leukemia cutis associated with myelodysplastic syndrome: A case report and literature review

RATIONALE

Myeloid sarcoma (MS) and leukemia cutis (LC) are extramedullary tumors comprising myeloid blasts. They can occur de novo or concurrently with hematological disorders, usually acute myeloid leukemia (AML). AML chemotherapy is generally the initial therapy for MS and LC, and hematopoietic stem cell transplantation (HSCT) can be considered as additional therapy. However, treatment for older patients who are unable to continue intensive chemotherapy is not currently standardized.

PATIENT CONCERNS

A 71-year-old Japanese woman was diagnosed with multiple MSs associated with myelodysplastic syndrome (MDS), using bone marrow aspiration and lymph node biopsy.

DIAGNOSES

Additionally, LC was diagnosed by skin biopsy. Extramedullary MS and LC lesions were formed by massive infiltration of myeloblastic cells.

INTERVENTIONS

Twenty courses of 5-azacytidine (5-Aza) were administrated as maintenance therapy after induction therapy with daunorubicin and cytarabine.

OUTCOMES

Myeloblasts decreased in the bone marrow and the LC disappeared after induction therapy. The MSs completely disappeared, except for the palatine tonsil lesion, after 5-Aza maintenance therapy. 5-Aza treatment provided long-term partial response for more than 21 months.

LESSONS

5-Aza was well tolerated and may be a good option for the treatment of MS and LC associated with MDS, especially in older patients who cannot receive HSCT.

Comprehensive evaluation of immunomodulation by moderate hypoxia in S. agalactiae vaccinated Nile tilapia

Streptococcus agalactiae is a major bacterial pathogen in tilapia aquaculture. Vaccines are known to provide protection but S. agalactiae clearance in tilapia can be reduced by marginal environmental conditions. Therefore, the purpose of this study is to examine S. agalactiae clearance in vaccinated Nile tilapia under moderate hypoxic (55± 5% DO) and normoxic (85 ± 5%DO) conditions. Fish were acclimatized to either moderate hypoxia or normoxia and immunized with formalin-inactivated S. agalactiae. Fish were experimentally challenged with S. agalactiae at 30 days post-vaccination. Serum antibody titer was significantly higher in vaccinated fish kept under normoxic condition compared to the moderate hypoxic condition at fifteen and thirty days post-vaccination. The cumulative mortality following challenge was significantly reduced in vaccinated fish kept under normoxic condition compared to those in moderate hypoxic condition reflecting that pre-challenge antibody titer may correlate with survival of fish. Blood and tissue pathogen burden detection of S. agalactiae studies revealed that culturable S. agalactiae cells could not be detected in the blood of normoxic vaccinated fish at all the sampling points. In contrast, fish vaccinated in moderate hypoxic condition had considerable number of culturable S. agalactiae cells in their blood up to 5 days following challenge. Phagocytosis and intracellular reactive oxygen species (ROS) production were lowered by moderate hypoxia in vitro. Furthermore, presence of specific antibodies and higher specific antibody level in the serum increased phagocytosis, ROS production and lowered intracellular survival of S. agalactiae in head kidney leukocytes. Overall this study has highlighted that S. agalactiae clearance in vaccinated Nile tilapia is modulated by moderate hypoxia. One of the possible explanations for this might be less efficient phagocytic activities due to low oxygen availability and lower specific antibody production in vaccinated fish.

Successful umbilical cord blood hematopoietic stem cell transplantation in a patient with adult T-cell leukemia/lymphoma initially achieving complete remission with anti-CC chemokine receptor 4 antibody combined chemotherapy

A 62-year-old man with CHOP refractory adult T-cell leukemia/lymphoma (ATLL) received anti-CC chemokine receptor 4 antibody (mogamulizumab) combined with CHOP and achieved complete remission. At 71 days after the final administration of mogamulizumab, he received umbilical cord blood transplantation (CBT) using reduced intensity conditioning. Umbilical cord blood engraftment was confirmed on day16. Grade II acute graft-versus-host disease (GVHD) was diagnosed on day60 and was controlled by administration of methylprednisolone. There was no evidence of relapse at 9 months after CBT. Ratios of regulatory T cells in CD4 positive T cells were remarkably low during all of these periods. Since mogamulizumab reduces regulatory T cells, the frequency and severity of acute GVHD were reported to be increased in patients administered mogamulizumab before allogenic stem cell transplantation. Further experiences are needed for selecting optimal donor sources, the portability period and GVHD prophylaxis for patients using mogamulizumab before allogeneic stem cell transplantation.

Development of a dye molecule-biocatalyst hybrid system with visible-light induced carbon–carbon bond formation from CO2 as a feedstock

Recently, CO₂ utilization technology, including artificial photosynthesis, has received much attention. In this field, CO₂ is used as a feedstock for fuels, polymers and in other chemical processes. Of note are malic enzymes (MEs) which catalyze the reaction of malic acid to pyruvic acid and CO₂ with the co-enzyme NADP⁺, and catalyze the reverse reaction of pyruvic acid and CO₂ to malic acid with the co-enzyme NADPH. Thus, MEs are also an attractive biocatalyst for carbon–carbon bond formation from CO₂. Studies of the visible light-induced malic acid production from pyruvic acid and CO₂ using an electron donor, a photosensitizer, an electron mediator, ferredoxin-NADP⁺ reductase, NADP⁺, and ME have been reported. However, modification of these systems is required, as they are very complicated. In this study, the visible light-induced carbon–carbon bond formation from pyruvic acid and CO₂ with ME using the photoreduction of 1,1′-diphenyl-4,4′-bipyridinium salt derivatives as a novel electron mediator with water-soluble tetraphenylporphyrin tetrasulfonate (H₂TPPS) in the presence of triethanolamine (TEOA) as an electron donor was developed. When a sample solution containing TEOA, H₂TPPS, 1,1′-diphenyl-4,4′-bipyridinium salt derivative, pyruvic acid, and ME in CO₂-saturated bis–tris buffer was irradiated, the major product was oxaloacetic acid. Thus, a visible light-induced photoredox system for carbon–carbon bond formation from CO₂ with ME using 1,1′-diphenyl-4,4′-bipyridinium salt derivative as an electron mediator was developed.

Influence of moderate hypoxia on vaccine efficacy against Vibrio anguillarum in Oreochromis niloticus (Nile tilapia)

Hypoxia is known as a potential immunomodulator in fish. This study therefore assesses the impact of chronic, moderate hypoxia on vaccine efficacy in Oreochromis niloticus. Serum antibody titer was used as a surrogate marker to detect vaccine efficacy. The fish were acclimatized to either moderate hypoxia (55 ± 5% DO) or normoxia (85 ± 5%DO) and immunized with formalin inactivated Vibrio anguillarum. Significantly, a higher antibody titer was found in normoxic fish than in moderate hypoxia. The normoxic group titer peaked at 14th dpv (days post vaccination) while the moderate hypoxic group peaked at 21st or 28th dpv. The absolute blood lymphocyte counts and serum bactericidal activities against V. anguillarum were significantly higher in normoxic fish. Serum killing of V. anguillarum appeared to be mainly via antibody-dependent classical complement pathway. Furthermore, the first week following vaccination appears critical for antibody production. This view was further supported by results obtained from gene expression assay, where the transcription level of all the detected immune related genes (IgM, IL-1 β, TCR-β, MHC-II β), except B cell activating factor, were significantly suppressed following exposure to moderate hypoxia. The overall results highlight that even though moderate hypoxia is not easily detectable in Oreochromis niloticus, it negatively affects antibody production by suppressing and delaying antibody response, ultimately affecting vaccine efficacy.

Comparative analysis of two types of CXCL8 from Japanese flounder (Paralichthys olivaceus)

A new type of CXCL8, named CXCL8_L1b, was identified in this research. Comparison of amino acid sequences of Japanese flounder CXCL8_L1b and CXCL8_L1a (BAB86884.1) showed only 41.2% identity. Transcripts of CXCL8_L1a were highly detected in spleen, kidney, gill and liver, while transcripts of CXCL8_L1b only were detected highly in spleen and kidney of apparently healthy fish. In fish challenged with E. tarda, transcripts of CXCL8_L1a were significantly increased at day 6, while no significant increase was detected in the mRNA level of CXCL8_L1b. On the other hand, fish infected by S. iniae significantly increased both transcripts of CXCL8_L1a and CXCL8_L1b at days 1 and 3. In VHSV-infected fish, only the transcripts of CXCL8_L1b were significantly induced at day 6. LPS and poly I:C stimulation of PBLs induced a high level of CXCL8_L1a transcripts, while CXCL8_L1b transcripts were significantly increased only post poly I:C treatment. To evaluate the chemotactic activity of CXCL8_L1a and CXCL8_L1b, Japanese flounder were intramuscularly injected with recombinant plasmids pCI-CXCL8_L1a and pCI-CXCL8_L1b. H & E staining showed that injections of both pCI-CXCL8_L1a and pCI-CXCL8_L1b caused strong immune responses in the form of intermuscular cell infiltration and capillary congestion. Injection of pCI-CXCL8_L1a and pCI-CXCL8_L1b significantly induced the expressions of genes related to inflammatory response such as IL-6 and CD8α on day 1 post-injection. The transcripts of IgM only significantly increased on day 7 post-injection of pCI-CXCL8_L1b.

Smad9 is a new type of transcriptional regulator in bone morphogenetic protein signaling

Smad1, Smad5 and Smad9 (also known as Smad8) are activated by phosphorylation by bone morphogenetic protein (BMP)-bound type I receptor kinases. We examined the role of Smad1, Smad5, and Smad9 by creating constitutively active forms (Smad(DVD)). Transcriptional activity of Smad9(DVD) was lower than that of Smad1(DVD) or Smad5(DVD), even though all three Smad(DVD)s associated with Smad4 and bound to the target DNA. The linker region of Smad9 was sufficient to reduce transcriptional activity. Smad9 expression was increased by the activation of BMP signaling, similar to that of inhibitory Smads (I-Smads), and Smad9 reduced BMP activity. In contrast to I-Smads, however, Smad9 did not inhibit the type I receptor kinase and suppressed the constitutively active Smad1(DVD). Smad9 formed complexes with Smad1 and bound to DNA but suppressed the transcription of the target gene. Taken together, our findings suggest that Smad9 is a new type of transcriptional regulator in BMP signaling.

Development of a serology-based assay for efficacy evaluation of a lactococcicosis vaccine in Seriola fish

Lactococcicosis is an infection caused by the bacterium Lactococcus garvieae and creates serious economic damage to cultured marine and fresh water fish industries. The use of the assay currently applied to evaluate the potency of the lactococcicosis vaccine is contingent upon meeting specific parameters after statistical analysis of the percent survival of the vaccinated yellowtail or greater amberjack fish after challenge with a virulent strain of L. garvieae. We found that measuring the serological response with a quantitative agglutinating antibody against the L. garvieae antigen (phenotype KG+) was an effective method of monitoring the potency of lactococcicosis vaccines. Vaccinated fish had significantly higher antibody titers than control fish when the L. garvieae Lg2-S strain was used as an antigen. Furthermore, the titer of the KG + agglutinating antibody was correlated with vaccine potency, and the cut-off titer was determined by comparing the data with those from the challenge test. An advantage of the proposed serology-based potency assay is that it will contribute to reduced numbers of animal deaths during vaccine potency evaluations.

ACVR1 (587T>C) mutation in a variant form of fibrodysplasia ossificans progressiva: second report

Fibrodysplasia ossificans progressiva (FOP) is a rare, congenital disorder caused by heterozygous mutation of the bone morphogenetic protein type I receptor ACVR1. Various forms of atypical FOP have recently been identified, and a novel mutation, ACVR1 (587T>C), was reported in 2011. We report on the second patient worldwide with ACVR1 (587T>C) mutation. A 22-year-old Japanese male with no family history of heterotopic ossification did not show any malformation of the great toes and showed normal development from birth to the age of 17 years, when heterotopic ossification appeared in the lumbar area. The clinical symptoms were similar to those reported previously: the delayed onset with a slower and mild clinical course and little finger camptodactyly. Gene analysis revealed that the patient was heterozygous for ACVR1 (587T>C) mutation, the same one as reported in 2011, suggesting a correlation between the location of the mutation and the clinical symptoms. This second report of ACVR1 (587T>C) mutation worldwide is particularly meaningful in that it highlights the difference between clinical symptoms of the first reported patient with ACVR1 (587T>C) mutation and those of classic FOP.

Disease-causing allele-specific silencing against the ALK2 mutants, R206H and G356D, in fibrodysplasia ossificans progressiva

Fibrodysplasia ossificans progressiva (FOP) is an autosomal dominant congenital disorder characterized by progressive heterotopic bone formation. Currently, no definitive treatment exists for FOP. The activin receptor type IA / activin-like kinase 2 (ACVR1/ALK2) gene has been identified as the responsible gene for FOP, and disease-associated ALK2 mutations have been found. Chemical inhibitors to the pathogenic ALK2 receptors are considered possible medical agents for FOP, but their adverse effects on normal ALK2 and other receptors cannot be excluded. Here we describe another treatment strategy for FOP using allele-specific RNA interference (ASP-RNAi), and show modified small interfering RNAs (siRNAs) conferring allele-specific silencing against disease-causing ALK2 mutants found in FOP, without affecting normal ALK2 allele. Thus, the siRNAs presented here may become novel therapeutic agents for FOP, and their induced ASP-RNAi may pave the way for the achievement of radical treatment of FOP and/or for the relief of its severe symptoms.