Marinobacter shengliensis subsp. alexandrii Subsp. Nov., Isolated from Cultivable Phycosphere Microbiota of Highly Toxic Dinoflagellate Alexandrium catenella LZT09 and Description of Marinobacter shengliensis Subsp. shengliensis Subsp. Nov.

Phycosphere hosts the boundary of unique holobionts harboring dynamic algae-bacteria interactions. During our investigating the microbial consortia composition of phycosphere microbiota (PM) derived from diverse harmful algal blooms (HAB) dinoflagellates, a novel rod-shaped, motile and faint yellow-pigmented bacterium, designated as strain LZ-6 T, was isolated from HAB Alexandrium catenella LZT09 which produces high levels paralytic shellfish poisoning toxins. Phylogenetic analysis based on 16S rRNA gene and two housekeeping genes, rpoA and pheS sequences showed that the novel isolate shared the highest gene similarity with Marinobacter shengliensis CGMCC 1.12758 T (99.6%) with the similarity values of 99.6%, 99.9% and 98.5%, respectively. Further phylogenomic calculations of average nucleotide identity (ANI), average amino acid identity (AAI) and digital DNA-DNA hybridization (dDDH) values between strains LZ-6 T and the type strain of M. shengliensis were 95.9%, 96.4% and 68.5%, respectively. However, combined phenotypic and chemotaxonomic characterizations revealed that the new isolate was obviously different from the type strain of M. shengliensis. The obtained taxonomic evidences supported that strain LZ-6 T represents a novel subspecies of M. shengliensis, for which the name is proposed, Marinobacter shengliensis subsp. alexandrii subsp. nov. with the type strain LZ-6 T (= CCTCC AB 2018388TT = KCTC 72197 T). This proposal automatically creates Marinobacter shengliensis subsp. shengliensis for which the type strain is SL013A34A2T (= LMG 27740 T = CGMCC 1.12758 T).

An fusaric acid-based CRISPR library screen identifies MDH2 as a broad-spectrum regulator of Fusarium toxin-induced cell death.

Fusarium mycotoxins are of great concern because they are the most common food-borne mycotoxins and environmental contaminants worldwide. Fusaric acid (FA), Deoxynivalenol (DON), Zearalenone (ZEA), T-2 toxin (T-2), and Fumonisin B1 (FB1) are important Fusarium toxins contaminating feeds and food and can cause serious health problems. FA can synergize with some other Fusarium toxins to enhance overall toxicity. However, the underlying molecular mechanism remains poorly understood. In this study, our CRISPR screening revealed Malate dehydrogenase 2 (MDH2) and Pyruvate dehydrogenase E1 subunit beta (PDHB) are the key genes for FA-induced cell death. Pathways associated with mitochondrial function, notably the TCA cycle, play a significant role in FA cytotoxicity. We found that MDH2 and PDHB depletion reduced FA-induced cell death, ROS accumulation, and the expression of caspase-3 and HIF-1α. The cell viability assays and flow cytometry demonstrated that MDH2 knockout but not PDHB decreased DON, ZEA, T-2, and FB1-induced cytotoxicity, apoptosis, and ROS accumulation. MDH2 inhibitor LW6 also decreased DON, ZEA, T-2, and FB1-induced toxicity. This suggested that MDH2, but not PDHB, is a common regulator of broad-spectrum Fusarium toxin (FA, DON, ZEA, T-2, and FB1)-induced cell death. Our work provides new avenues for the treatment of Fusarium toxin toxicity.

Seroprevalence of Epizootic Hemorrhagic Disease Virus in Guangdong Cattle Farms during 2013-2017, China.

Epizootic hemorrhagic disease (EHD) is an infectious viral disease caused by epizootic hemorrhagic disease virus (EHDV) and EHDV frequently circulates in wild and domestic ruminants. Sporadic outbreaks of EHD have caused thousands of deaths and stillbirths on cattle farms. However, not much is known about the circulating status of EHDV in Guangdong, southern China. To estimate the seroprevalence of EHDV in Guangdong province, 2886 cattle serum samples were collected from 2013 to 2017 and tested for antibodies against EHDV using a competitive ELISA. The overall seroprevalence of EHDV reached 57.87% and was highest in autumn (75.34%). A subset of positive samples were serotyped by a serum neutralization test, showing that EHDV serotypes 1 and 5-8 were circulating in Guangdong. In addition, EHDV prevalence always peaked in autumn, while eastern Guangdong had the highest EHDV seropositivity over the five-year period, displaying apparent temporal-spatial distribution of EHDV prevalence. A binary logistic model analysis indicated a significant association between cattle with BTV infections and seroprevalence of EHDV (OR = 1.70, p < 0.001). The co-infection of different serotypes of EHDV and BTV raises a high risk of potential genomic reassortment and is likely to pose a significant threat to cattle, thus urging more surveillance to monitor their circulating dynamics in China.

Ancylostoma ceylanicum Infection in a Miniature Schnauzer Dog Breed.

PURPOSE: Canine hookworm disease is a global zoonotic parasitic disease caused by a variety of nematodes in families Ancylostomatidae, including Ancylostoma spp., Necator spp., and Uncinaria spp., in the small intestine (mainly the duodenum) of dogs. The disease is widely distributed in China. The purpose of this study is to systematically diagnose and treat canine hookworm disease through the case of miniaturization Schnauzer dog feed infected with A. ceylanicum, so as to provide experimental basis for subsequent prevention and control of canine hookworm disease. METHODS: In the current study, we isolated hookworm eggs from a diseased miniature schnauzer, then the polymerase chain reaction (PCR) was used to amplify the ITS1-5.8S-ITS2 gene sequence from genomic DNA extracted from hookworms. Phylogenetic analysis based on ITS1-5.8S-ITS2 gene sequence sequences was inferred using MEGA-X. After phylogenetic analysis, etiologic and symptomatic therapies were used to treat the canine hookworm disease. RESULTS: The sequencing results showed that the length of the ITS1-5.8S-ITS2 gene sequence was approximately 960 bp, and ITS1 and ITS2 were extracted to analyze similarity with other hookworms to build a phylogenetic tree. After phylogenetic analysis, the results showed that the diseased miniature schnauzer was infected by A. ceylanicum. Using etiologic and symptomatic therapies, the sick dog with an A. ceylanicum infection was also treated for 5 days. CONCLUSIONS: To our knowledge, this is the first report of diagnosis and treatment for canine hookworm disease in Guangzhou city. In addition, with the improvement of economic level, the scale of pet dog breeding is also increasing. The diagnostic methods and treatment schemes adopted in this report will help to standardize the prevention and control of canine hookworm disease.

Characterization of cattle-origin ticks from Southern China.

To characterize ticks in cattle from Guangdong Province and Guangxi Zhuang Nationality Autonomous Region, Southern China, 783 cattle in four localities were examined. Among them, 232 (29.63%) cattle were positive for tick infection. A total of 503 ticks collected in these cattle were further investigated. Two Rhipicephalus species, namely R. microplus and R. sanguineus, were firstly identified by morphological features. Thereinto, R. microplus is the prevalent species in cattle in southern China, with high prevalent in summer and autumn annually. Mixed infection of R. microplus and R. sanguineus was just found in yellow cattle. To further confirm the morphological identification of these cattle-origin ticks, a phylogeographic analysis inferred from the sequences of the ribosomal internal transcribed spacer-2 (ITS-2) was performed, and R. microplus and R. sanguineus were identified. However, the morphological taxonomy of R. microplus has been challenged in recent years. The mitochondrial cytochrome c oxidase subunit 1 (cox1) marker was then used to provide higher resolution of R. mircoplus complex. The re-constructed cox1 phylogenetic tree further identified these R. mircoplus tick samples as R. microplus Clade A. These findings illustrated the prevalence and characterization of cattle-origin ticks in Southern China for the first time, and provided base-line information for further control of tick and tick-borne disease in these areas.