Diversity and Biosynthetic Potential of Culturable Microbes Associated with Toxic Marine Animals

Tetrodotoxin (TTX) is a neurotoxin that has been reported from taxonomically diverse organisms across 14 different phyla. The biogenic origin of tetrodotoxin is still disputed, however, TTX biosynthesis by host-associated bacteria has been reported. An investigation into the culturable microbial populations from the TTX-associated blue-ringed octopus Hapalochlaena sp. and sea slug Pleurobranchaea maculata revealed a surprisingly high microbial diversity. Although TTX was not detected among the cultured isolates, PCR screening identifiedsome natural product biosynthesis genes putatively involved in its assembly. This study is the first to report on the microbial diversity of culturable communities from H. maculosa and P. maculata and common natural product biosynthesis genes from their microbiota. We also reassess the production of TTX reported from three bacterial strains isolated from the TTX-containing gastropod Nassarius semiplicatus.     

The release and uptake of metals from potential biofilm inhibition products during spiny lobster (Sagmariasus verreauxi,H. Milne Edwards 1851) culture

Zinc (Zn) and copper (Cu) are strong inhibitors of bacterial biofilms in aqueous solutions, but are known toxins of crustaceans. A new metal application method; cold‐sprayed metal embedment, known to modulate metal release, was tested for its applications in crustacean larval culture systems. Cold‐spray technology allows metal particles to bond to plastics, while modulating metal ion release and biocide activity to the substrate boundary. In this study, Eastern spiny lobster (Sagmariasus verreauxi) larvae (phyllosoma) were cultured in the presence of cold‐sprayed Zn and Cu metal surfaces. Metal loss was monitored gravimetrically on embedded surfaces, assessment of water ion concentrations and analysis of phyllosoma body content were undertaken. Phyllosoma moulting, deformity and mortality patterns were monitored. Cold‐sprayed Zn‐ and Cu‐embedded surfaces were depleted with losses of 0.69% and 31.2% noted respectively. Culture water concentrations of these metals were elevated and accumulation by phyllosoma occurred. Water Zn concentrations of 18.5 μg L^?1 were associated with chronic eyestalk moult deformities; the first report of Zn causing a non‐lethal moult deformity in crustacean larvae. The Cu surface lost a third of its metal mass with a water concentration of 40 μg L^?1 causing acute toxicity and localization of composite granules in the midgut gland. Cu associated mortality was noted by Day 2 of culture with a LD 50 experienced by Day 9. Future work on the use of bioactive metals in aquaculture systems will focus on a range of different metal alloys, and improved modulation of ion release mechanisms through increased particle embedment depth and separation.     

Benazepril and subclinical feline hypertrophic cardiomyopathy: a prospective, blinded, controlled study

Twenty-one cats with hypertrophic cardiomyopathy were enrolled in this study to determine if the administration of benazepril (0.5 mg/kg body weight [BW], PO, q24h) to cats with subclinical hypertrophic cardiomyopathy improves cardiac diastolic function and reverses left ventricular hypertrophy when compared with diltiazem controlled delivery (CD) (10 mg/kg BW, PO, q24h). Cats were evaluated at day 0 and after 3 and 6 months of therapy. In the benazepril group (n = 11), the diastolic transmitral flow of the E and A waves ratio (E/A ratio) increased significantly between 0 and 6 months (P = 0.009) and the thickness of the left ventricular free wall in systole (LVFWs) decreased significantly between 0 and 3 months (P = 0.04). In the diltiazem CD group (n = 5), none of the parameters varied significantly throughout the study. There was no difference between the benazepril and the diltiazem CD group throughout the study. Therefore, the variations observed for the E/A ratio and the LVFWs may have been incidental. Further studies will be needed to establish the role of benazepril in subclinical hypertrophic cardiomyopathy in cat.     

Heart disease in cattle with clinical signs of heart failure: 59 cases

This retrospective study identified clinical signs, underlying cardiac conditions, blood findings, echocardiographic findings, and prognosis for 59 cattle with clinical signs of congestive heart failure. Signalment; history; clinical signs; clinicopathologic, echocardiographic, and radiographic findings; and treatment were determined by reviewing medical records. Follow-up information was obtained by telephone conversation with owners. Most patients were tachycardic (n = 50), and tachypneic (n = 55). Pericarditis of traumatic origin (n = 21), by extension from pleuritis (n = 3), or of idiopathic origin (n = 1) was diagnosed in 25 cases. Other diagnoses were congenital heart defect (n = 13), cardiomyopathy (n = 9), bacterial endocarditis (n = 7), and neoplasm (n = 5). Twelve cases (20%) were discharged. Long-term survival was good in 2 out of 3 cases treated by pericardiostomy. The prognosis is poor in cases of heart failure in cattle and deaths within 1 mo (n = 3) or between 1 to 3 mo after discharge (n = 3) were common in cases for which follow-up was available (n = 8).     

A study of heart diseases without clinical signs of heart failure in 47 cattle

In this retrospective study, features of 47 cattle suffering from heart disease (HD) without clinical signs of heart failure (HF) were reviewed. The most common reasons for referral were respiratory problems (n =14), anorexia (n = 13), fever (n = 10), and lameness (n = 9). Thirty-nine animals were tachypneic. In 31 cases, cardiac auscultation revealed abnormalities. The final diagnoses were bacterial endocarditis (BE; n = 19), congenital heart disease (CHD; n = 18), pericarditis (n = 8), cardiomyopathy (n = 1), and lymphoma (n = 1). Echocardiography was performed in 39 cases. Gross pathology examination confirmed the echocardiographic diagnosis in 4 of 5 cases of pericarditis, 6 of 6 cases of BE, and 4 of 6 cases of CHD. Short-term prognosis was guarded with 19 cases (40.4%) being discharged. Premature death within 2 mo after discharge (n = 5), early culling because of poor breeding performance (n = 5), and normal productive life in the herd (n = 5) were observed in the cases that were followed. Echocardiography may be the most sensitive tool for the antemortem diagnosis of heart disease in cattle.