Profiling of Brevetoxin Metabolites Produced by Karenia brevis 165 Based on Liquid Chromatography-Mass Spectrometry

In this study, Karenia brevis 165 (K. brevis 165), a Chinese strain, was used to research brevetoxin (BTX) metabolites. The sample pretreatment method for the enrichment of BTX metabolites in an algal culture medium was improved here. The method for screening and identifying intracellular and extracellular BTX metabolites was established based on liquid chromatography-time-of-flight mass spectrometry (LC-ToF-MS) and liquid chromatography triple quadrupole tandem mass spectrometry (LC-QqQ-MS/MS). The results show that the recovery rates for BTX toxins enriched by a hydrophilic–lipophilic balance (HLB) extraction column were higher than those with a C18 extraction column. This method was used to analyze the profiles of extracellular and intracellular BTX metabolites at different growth stages of K. brevis 165. This is the first time a Chinese strain of K. brevis has been reported that can produce toxic BTX metabolites. Five and eight kinds of BTX toxin metabolites were detected in the cell and culture media of K. brevis 165, respectively. Brevenal, a toxic BTX metabolite antagonist, was found for the first time in the culture media. The toxic BTX metabolites and brevenal in the K. brevis 165 cell and culture media were found to be fully proven in terms of the necessity of establishing a method for screening and identifying toxic BTX metabolites. The results found by qualitatively and quantitatively analyzing BTX metabolites produced by K. brevis 165 at different growth stages show that the total toxic BTX metabolite contents in single cells ranged between 6.78 and 21.53 pg/cell, and the total toxin concentration in culture media ranged between 10.27 and 449.11 μg/L. There were significant differences in the types and contents of toxic BTX metabolites with varying growth stages. Therefore, when harmful algal blooms occur, the accurate determination of BTX metabolite types and concentrations will be helpful to assess the ecological disaster risk in order to avoid hazards and provide appropriate disaster warnings.

Simultaneous enterovirus EV-D68 and CVA6 infections causing acute respiratory distress syndrome and hand, foot and mouth disease

Background Although most enterovirus (EV) infections can be asymptomatic, these viral agents can cause serious conditions associated with central nervous system, respiratory disease and uncommon manifestations of hand, foot and mouth disease (HFMD). EV-coinfections have been rarely reported with development of complications and severe clinical outcome. An atypical case of a child presenting HFMD and severe acute respiratory syndrome, co-infected with EV-D68 and CVA6, is reported herein. Case presentation A 3-year-old boy was admitted in the emergency department unit showing fever, abdominal pain and tachycardia. Twenty-four hours after hospitalization the child developed severe clinical symptoms associated with HFMD and was discharged after recovery. Two days later, the child was readmitted with fever, cough and respiratory distress. RT-PCR and Sanger sequencing confirmed positivity for EV-D68 and CVA6 in oro and nasopharynges swabs and vesicles fluid, respectively. Phylogenetic analysis based on VP1 gene sequences suggested that CVA6 was closely related with HFMD viruses circulating in Turkey, while EV-D68 was genetically related to a Chinese strain. Conclusions To the best of our knowledge, this case is the first report of a double infection caused by CVA6 and EV-D68, which shed light on the pathogenesis of enterovirus infections. Further studies must be conducted to ascertain the role and clinical significance of EV co-infections, as well as a potential synergistic pathway between these viruses.

A New Strain of Virus Discovered in China Specific to the Parasitic Mite Varroa destructor Poses a Potential Threat to Honey Bees

The ectoparasitic mite, Varroa destructor, feeds directly on honey bees and serves as a vector for transmitting viruses among them. The Varroa mite causes relatively little damage to its natural host, the Eastern honey bee (Apis cerana) but it is the most devastating pest for the Western honey bee (Apis mellifera). Using Illumina HiSeq sequencing technology, we conducted a metatranscriptome analysis of the microbial community associated with Varroa mites. This study led to the identification of a new Chinese strain of Varroa destructor virus-2 (VDV-2), which is a member of the Iflaviridae family and was previously reported to be specific to Varroa mites. A subsequent epidemiological investigation of Chinese strain of VDV-2 (VDV-2-China) showed that the virus was highly prevalent among Varroa populations and was not identified in any of the adult workers from both A. mellifera and A.cerana colonies distributed in six provinces in China, clearly indicating that VDV-2-China is predominantly a Varroa-adapted virus. While A. mellifera worker pupae exposed to less than two Varroa mites tested negative for VDV-2-China, VDV-2-China was detected in 12.5% of the A. mellifera worker pupae that were parasitized by more than 10 Varroa mites, bringing into play the possibility of a new scenario where VDV-2 could be transmitted to the honey bees during heavy Varroa infestations. Bioassay for the VDV-2-China infectivity showed that A. cerana was not a permissive host for VDV-2-China, yet A. mellifera could be a biological host that supports VDV-2-China’s replication. The different replication dynamics of the virus between the two host species reflect their variation in terms of susceptibility to the virus infection, posing a potential threat to the health of the Western honey bee. The information gained from this study contributes to the knowledge concerning genetic variabilities and evolutionary dynamics of Varroa-borne viruses, thereby enhancing our understanding of underlying molecular mechanisms governing honey bee Varroosis.

Reaction of Indian Chicks to Klebsiella Pneumoniae Strain Borkar, a Plant Pathogen Causing Pneumonia in Plants

Klebsiella pneumoniae is emerging as an important bacterial plant pathogen in Asia region particularly in China and India. The Chinese strain of Klebsiella pneumoniae causing top rot of maize is reported to be pathogenic on mice also. The Indian strain of Klebsiella pneumoniae causing root bark necrosis and wilt in pomegranate is found non- pathogenic on Indian bird chicken, thereby indicating it to be plant host specific.

Genetic Analysis of Field Isolates of Infectious Bursal Disease Virus in Iraqi Farms

Sixty samples of bursa of Fabricius were collected from broiler chickens suspected to be infected with infectious bursal disease virus (IBDV) in different areas of Iraq. The extracted nucleic acid was amplified using reverse transcriptase polymerase chain reaction (RT-PCR) targeting genes of segment A (Vp2, Vp3, Vp4 and Vp5 genes) and segment B (VP1 genes). The products of amplification were sent to Korea for sequencing using Sanger method. The sequencing analysis of the IBDV from the Iraqi isolates revealed that each gene had different transition and transversion (nonsense and missense of point mutation) compared to reference genes. The phylogenetic tree analysis showed that the VP2 of segment A of the Iraqi samples was similar to that of an Egyptian strain with 96%similarity, the polypeptide VP2-3-4 of segment A of the Iraqi samples were similar to those of a Chinese strain 99%similarity and the VP5 of segment A was similar to that of Chinese strain with 99% similarity. However, the phylogenetic tree analysis showed that the VP1 of segment B had 95% similarity with that of a Chinese strain.

Complete Genome Sequence of Porcine Deltacoronavirus Strain CH/JXJGS01/2016, Isolated in Jiangxi Province, China, 2016

ABSTRACT The complete genome sequence of a variant of porcine deltacoronavirus, isolated from a diarrheal piglet and designated CH/JXJGS01/2016, was sequenced and analyzed. Phylogenetic analysis demonstrated that CH/JXJGS01/2016 shares the highest nucleotide and amino acid identities with the Chinese strain NH (GenBank accession number KU981059).