Genomic insights into novel Erwinia bacteriophages: unveiling their Henunavirus membership and host infection strategies.

Erwinia amylovora, the primary causative agent of blight disease in rosaceous plants, poses a significant threat to agricultural yield worldwide, with limited effective countermeasures. The emergence of sustainable alternative agents such as bacteriophages is a promising solution for fire blight that specifically targets Erwinia. In this study, we isolated pEp_SNUABM_01 and pEa_SNUABM_55 from a South Korean apple orchard soil, analyzed their genomic DNA sequences, and performed a comprehensive comparative analysis of Hena1 in four distinct sections. This study aimed to unveil distinctive features of these phages, with a focus on host recognition, which will provide valuable insights into the evolution and characteristics of Henunavirus bacteriophages that infect plant pathogenic Erwinia spp. By elucidating the distinct genomic features of these phages, particularly in terms of host recognition, this study lays a foundation for their potential application in mitigating the risks associated with fire blight in Rosaceae plants on a global scale.

Blood Fluke Infection (Spirorchidiasis) and Systemic Granulomatous Inflammation: A Case Study of Green Sea Turtles (Chelonia mydas) on Jeju Island, South Korea.

Despite the precarious state of marine turtles as a highly endangered species, our understanding of their diseases remains limited. This case report presents a detailed pathological investigation of spirorchiidiasis, a blood fluke infection that poses a substantial threat to marine turtles. This retrospective study examined three cases of spirorchiid-infected sea turtles, specifically, green sea turtles stranded on Jeju Island, South Korea. Premortem examination of the three spirorchiid-infected green sea turtles demonstrated nonspecific clinical symptoms; blood analysis revealed dehydration, malnutrition, and anemia. Computed tomography scans provided insights into severe pulmonary and extrapulmonary manifestations, including the mass present in the joint region. Post-mortem examinations consistently indicated severe lung lesions and systemic manifestations, with histopathological examination confirming the presence of spirorchiid ova across various organs. Despite the global prevalence of spirorchiidiasis in sea turtles, disease severity varies regionally. This report provides a detailed demonstration of the pathology of spirorchiidiasis in sea turtles from Northeast Asia.

Ingestion of fishing gear and Anisakis sp. infection in a beached Indo-Pacific finless porpoise (Neophocaena phocaenoides) in the Jeju Island, Republic of Korea: findings from post-mortem computed tomography and necropsy.

BACKGROUND: Human fishing activities have significantly affect environmental concern for marine ecosystems, conservation of marine mammals, and human health. Coastal cetaceans are highly vulnerable to ingestion of fishing gear, bycatching, or entanglement, all of which can be fatal for these animals. In particular, certain coastal dolphins and porpoises are heavily impacted by fishing gear such as angling gear or stownet, as their food often overlap with the target fish species of human fisheries. CASE PRESENTATION: This study presents a case of an Indo-Pacific finless porpoise (Neophocaena phocaenoides) beached on the coast of Jeju Island, Republic of Korea, with ingestion of fishing gear and severe Anisakis infection. Although this species inhabits waters ranging from the Persian Gulf to Taiwan, several stranded carcasses have been reported on Jeju Island in recent years. Post-mortem computed tomography revealed a bundle of four fishing hooks in the forestomach, along with nylon lines and steel lines with connectors, which were assumed to be angling gear for Jeju hairtail (Trichiurus lepturus). Further necroscopic investigation revealed that the forestomach contained a large number of Anisakis spp. (Nematoda: Anisakidae). Histological examination revealed a thickened forestomach wall with pinpoint and volcanic ulcerations, a thickened layer of stratified squamous epithelium, and infiltrated stroma in the squamous epithelium. CONCLUSIONS: This study emphasizes the urgent need to address the impact of fishing activities on marine mammals, marine litter pollution, and the bycatch problem in Korean seawater. In addition, the occurrence of N. phocaenoides in seawater around Jeju Island should be raised in future geographical ecology or veterinary pathology studies and when its distribution is updated.

Effect of dietary heat-killed Lactiplantibacillus plantarum VSG3 on growth, immunity, antioxidant status, and immune-related gene expression in pathogen-aggravated Cyprinus carpio.

Heat-killed probiotics offer an alternative approach to enhance growth and disease resistance in farmed fish. In this study, we isolated Lactiplantibacillus plantarum VSG3 from the gut of Labeo rohita to investigate the effects of heat-killed L. plantarum (HK-LP) on the health and growth performance of Cyprinus carpio fingerlings. Different concentrations of HK-LP (0, 50, 100, 200, 300, and 400 mg/kg) were administered to the fish, followed by a challenge with Aeromonas hydrophila after 8 weeks of feeding. Notably, the LP200 group exhibited significantly improved percentage weight gain and specific growth rate, accompanied by the lowest feed conversion ratio. Post-challenge survival rates were considerably enhanced in the LP200 group, reaching 60.65%. Moreover, serum analysis indicated significantly higher levels of total protein and albumin in the LP200 group than in the control group. Although HK-LP had no substantial impact on certain serum parameters (glucose, total cholesterol, cortisol, and alanine aminotransferase), aspartate aminotransferase levels were considerably low in the LP200 group. Intestinal protease and trypsin activities significantly increased in the LP200 group, while no significant changes were observed in lipase and amylase activities post-pathogen challenge. Serum immunological indices, including lysozyme, alternative complement pathway, and phagocytic activity, improved considerably in the LP200 group. Additionally, serum antioxidant enzyme activities (superoxide dismutase [SOD], glutathione peroxidase [GPx], catalase [CAT], and myeloperoxidase) were significantly elevated in the LP200 group, while malondialdehyde level was reduced. Gene expression analysis in liver tissue indicated strong upregulation of antioxidant-related genes (SOD, CAT, nuclear factor erythroid 2 [NFE2]-related factor 2 [Nrf2], Kelch-like ECH-associated protein 1[Keap1]) in the LP100 and LP200 groups. Pro-inflammatory cytokines (IL-1ß and TNF-α) were considerably downregulated in the kidneys of the LP200 post-challenged fish, although the anti-inflammatory cytokine IL-10 showed an increased expression. Quadratic regression analysis identified the optimal dietary HK-LP level for maximizing growth and immune performance (200.381-270.003 mg/kg). In summary, our findings underscore the potential of HK-LP as a valuable dietary supplement for enhancing carp aquaculture, particularly at the appropriate concentration.

First report of kyphoscoliosis in the narrow-ridged finless porpoises (Neophocaena asiaeorientalis): Findings from congenital and degenerative cases comparison using post-mortem computed tomography.

INTRODUCTION: Spinal deformities, including kyphoscoliosis, have been consistently documented in cetaceans. However, the majority of reported cases of kyphoscoliosis in cetaceans pertain to bottlenose dolphins, with limited information on its occurrence in narrow-ridged finless porpoise (NFP) (Neophocaena asiaeorientalis). MATERIALS AND METHODS: In November 2021, two deceased NFPs were discovered stranded on the shores of the Republic of Korea. As part of the pioneer stranded cetacean imaging programme in the Republic of Korea, both carcasses underwent post-mortem computed tomography (PMCT), revealing congenital and degenerative traumatic kyphoscoliosis, respectively. RESULTS: Although kyphoscoliosis may not have directly caused the demise of these individuals, it is hypothesized that the reduced spinal range of motion and mobility associated with kyphoscoliosis may have contributed to their deaths. CONCLUSION: This case report presents the first documented cases of kyphoscoliosis in two NFPs stranded in Korean waters, utilizing PMCT as an efficient methodology for assessing skeletal abnormalities in cetaceans.

Adhesive Bowel Obstruction (ABO) in a Stranded Narrow-Ridged Finless Porpoise (Neophocaena asiaeorientalis sunameri).

In this case report, we present a rare occurrence of a narrow-ridged finless porpoise (Neophocaena asiaeorientalis sunameri), discovered on the coast of Jeju Island, Republic of Korea, that was afflicted with adhesive bowel obstruction (ABO), a life-threatening condition that has scarcely been reported in cetaceans. Diagnosis of ABO was confirmed via radiological and clinical assessments. Post-mortem computed tomography and necropsy revealed ABO between two loops of the jejunum at the L8 level. The mesenteric tissue covering the intestinal lesion was severely thickened with increased tension. Both bowel loops were fixed to the mesentery and acutely angulated, leading to asymmetrical thickening of the cross-sectional bowel walls. The intestinal lumen was stenosed because of pressure from the firm mesenteric band, and no fecal matter was observed in the lumen of the posterior bowel or rectum. Calcified nodules were detected, and histological analysis suggested parasitic or suspected post-parasitic infections. The primary cause of the intestinal lesions is presumed to be a reaction related to parasitic infection. However, further investigations would establish a definitive link between parasitic infections and ABO in this species. This case highlights the importance of studying rare medical conditions in wildlife, providing valuable insights into marine mammal health.

Optimizing the formulation of Erwinia bacteriophages for improved UV stability and adsorption on apple leaves.

Fire blight is a bacterial disease that affects plants of the Rosaceae family and causes significant economic losses worldwide. Although antibiotics have been used to control the disease, concerns about their environmental impact and the potential to promote antibiotic resistance have arisen. Bacteriophages are being investigated as an alternative to antibiotics; however, their efficacy can be affected by environmental stresses, such as UV radiation. In this study, we optimized the formulation of Erwinia phages to enhance their stability in the field, focusing on improving their UV stability and adsorption using adjuvants. Our results confirmed that 4.5 % polysorbate 80 and kaolin improve phage stability under UV stress, resulting in an 80 % increase in PFU value and improved UV protection efficacy. Adsorption assays also demonstrated that polysorbate 80 and kaolin improved the absorption efficiency, with phages detected in plant for up to two weeks. These findings demonstrate the effectiveness of the auxiliary formulation of Erwinia bacteriophages against environmental stress.

Dietary Syzygium cumini leaf extract influences growth performance, immunological responses and gene expression in pathogen-challenged Cyprinus carpio.

This study evaluated the effects of jamun leaf extract (JLE) as a feed supplement on growth performance, haemato-immunological, oxidative stress-related parameters, and cytokine gene expression in Cyprinus carpio challenged with Aeromonas hydrophila.. Diets containing four different JLE concentrations, that is, 0 (basal diet), 5 (JLE5), 10 (JLE10), and 15 g kg-1 (JLE15), were fed to carp (6.17 ± 0.43 g) for eight weeks. Growth performance was significantly higher in JLE10. Haemato-immunological and antioxidant parameters were determined in fish at 48 h post-challenge with A. hydrohila. The cumulative survival was highest in JLE10 (69.69%) 14 days post-challenge. Serum protein (2.18 ± 0.06 g dL-1), lysozyme (32.38 ± 1.2 U mL-1), alternative complement pathway (70.43 ± 1.61 U mL-1), phagocytic activity (21.18 ± 0.48%), respiratory burst activity (0.289 ± 0.09 OD630nm), and immunoglobulin levels (6.67 ± 0.36 U mg mL-1) were significantly higher in JLE10 than in the control. Serum alanine aminotransferase (44.06 ± 1.62 Unit mL-1), aspartate aminotransferase (31.58 ± 1.82 Unit mL-1), and malondialdehyde (2.57 ± 0.26 nmol mL-1) levels were lower in JLE10 than in the control (p < 0.05), whereas myeloperoxidase activity was significantly higher in JLE5 and JLE10 than in the control. Superoxide dismutase levels in the serum were higher (p < 0.05) in JLE5 and JLE10 than in the other groups. Gene expression analysis revealed that the mRNA expression of pro-inflammatory cytokines TNF-α and IL-1ß was upregulated (p < 0.05) in the liver, head-kidney, and intestine of challenged carp in JLE10. The signalling molecule NF-κB p65 was upregulated in lymphoid organs in JLE10 but not in the liver. The anti-inflammatory cytokine IL-10 was significantly downregulated in challenged carp in JLE10 compared with that in the control. Quadratic regression analysis showed that optimal dietary JLE was estimated to be 9.03-10.15 g kg-1 to maximize the growth performance. Results of the present study revealed that dietary JLE at 10 g kg-1 can significantly improve the immunity and disease resistance of C. carpio. Thus, JLE is a promising food additive for carp aquaculture.

Evaluation of the Antimicrobial Potential and Characterization of Novel T7-Like Erwinia Bacteriophages.

The recent outbreak of blight in pome fruit plants has been a major concern as there are two indistinguishable Erwinia species, Erwinia amylovora and E. pyrifoliae, which cause blight in South Korea. Although there is a strict management protocol consisting of antibiotic-based prevention, the area and the number of cases of outbreaks have increased. In this study, we isolated four bacteriophages, pEp_SNUABM_03, 04, 11, and 12, that infect both E. amylovora and E. pyrifoliae and evaluated their potential as antimicrobial agents for administration against Erwinia-originated blight in South Korea. Morphological analysis revealed that all phages had podovirus-like capsids. The phage cocktail showed a broad spectrum of infectivity, infecting 98.91% of E. amylovora and 100% of E. pyrifoliae strains. The antibacterial effect was observed after long-term cocktail treatment against E. amylovora, whereas it was observed for both short- and long-term treatments against E. pyrifoliae. Genomic analysis verified that the phages did not encode harmful genes such as antibiotic resistance or virulence genes. All phages were stable under general orchard conditions. Collectively, we provided basic data on the potential of phages as biocontrol agents that target both E. amylovora and E. pyrifoliae.

Effects of Bougainvillea glabra leaf on growth, skin mucosal immune responses, and disease resistance in common carp Cyprinus carpio.

This study evaluated the effects of Bougainvillea glabra (BG) leaf as a feed supplement on growth, skin mucosal immune parameters, serum oxidative stress, expression of immune-related genes, and susceptibility to pathogen infection in carp Cyprinus carpio. Diets containing four different BG concentrations (g kg-1), i.e., 0 g (basal diet), 20 g (BG20), 30 g (BG30), 40 g (BG40), and 50 g (BG50), were fed to the carp (average weight: 14.03 ± 0.81 g) for 8 weeks. Skin mucosal immunological and serum antioxidant parameters were examined 8 weeks post-feeding. Growth performance was significantly higher in BG40. Among the examined skin mucosal immune parameters, lysozyme (33.79 ± 0.98 U mL-1), protein (6.88 ± 0.37 mg mL-1), immunoglobulin (IgM; 5.34 ± 0.37 unit-mg mL-1), and protease activity (3.18 ± 0.36%) were significantly higher in BG40 than in the control; whereas, there was no significant effect on the alkaline phosphatase level. Among serum immune activity, activities of lysozyme, the alternative complement pathway, and IgM were significantly higher in BG40. Phagocytic, and superoxide dismutase (SOD) activities were higher (P < 0.05) in BG30-BG50. Serum ALT, AST, and MDA levels were lower in BG40 than in the control (P < 0.05). Intestinal enzymatic activities were enhanced in BG40 and BG50 (P < 0.05), except for lipase in BG50. Gene expression analysis revealed that the mRNA expressions of antioxidant genes (SOD, GPx, and Nrf2), an anti-inflammatory gene (IL-10), and IκBα were significantly upregulated in BG40. Conversely, the pro-inflammatory gene IL-1ß and the signaling molecule NF-κB p65 were downregulated in BG40 and BG50, respectively. BG supplementation had no significant effect on TNF-α, TLR22, or HSP70 mRNA expressions. Moreover, fish in BG40 exhibited the highest relative post-challenge survival (67.74%) against Aeromonas hydrophila infection. These results suggested that dietary supplementation with BG leaves at 40 g/kg can significantly improve the growth performance, immune responses, and disease resistance of C. carpio. BG leaves are a promising food additive for carp in aquaculture.