Assessment of the Antibacterial Effect of Chitosan Coated with Heracleum persicum Oil on Rainbow Trout Quality

Today, due to the rapid spoilage of fish, the use of natural preservatives is a priority over those of synthetic varieties. Also, the natural antimicrobial effects of essential oils can help to increase shelf life. There are very few studies concerning the use of essential oils in this regard. In the present study, the antibacterial effect of chitosan coated with Heracleum persicum oil was investigated on the quality of rainbow trout. The control and the coated fish samples were analyzed periodically by generalized estimating equation (GEE) for total viable count (TVC), psychrophilic bacteria, total volatile base nitrogen (TVB-N), polyunsaturated fatty acids (PUFA), texture, taste, odor, and overall acceptance parameters. The results showed that by increasing the amount of chitosan, TVC, psychrophilic bacteria, and TVB-N decreased while PUFA, texture, taste, odor, and overall acceptance parameters increased.     

Antibacterial activities of a new combination of essential oils against marine bacteria

The antibacterial activities of essential oils and herbal extracts have been demonstrated against a range of bacterial species. In this study, the antibacterial effects of a new combination of essential oils from the herbs Thymus vulgaris, Salvia officinalis, Eucalyptus globulus and Mentha piperita were assayed against common bacterial isolates (Staphylococcus aureus, Escherichia coli and Pseudomonas aeroginosa) and fifteen novel marine bacteria isolates. The sensitivity of different isolates to antibacterial activity of the essential oils was determined using well diffusion assays. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) were quantified by micro dilution assays. The data demonstrate that the combination of essential oils had potent antibacterial effects and marine bacteria were more sensitive to growth inhibition (P < 0.05). MIC rates were 0.77–6.18 mg/ml, and MBC rates were 1.67–12.30 mg/ml. This indicates that the combined essential oils (CEO) can be a new source of antibacterial agents for use in marine aquaculture.     

Comparison of three immunodiagnostic tests for experimental Heterophyes heterophyes infection in dogs

The aim of this study was to compare the performance of three in-house diagnostic tests, i.e. counter current immunoelectrophoresis (CCIE), intradermal (ID) and indirect fluorescent immunoassay (IFI), for the diagnosis of Heterophyes infection. One hundred and twenty puppies were randomly divided into eight groups (n=15/group). Heterophyes heterophyes infections were established in these puppies by administering a dose of 50 H. heterophyes encysted metacercariae/puppy by gavage. Forty puppies of similar age and sex were divided into eight groups, of five puppies each and were used as negative controls. Sera pooled from separate infected and uninfected groups were tested against H. heterophyes antigens, weekly for 8 weeks post-infection (PI). The ID assay detected infected puppies sooner than any of the serological tests. Sero-conversion was first detected 2 weeks PI by ID assay and 1 week later by CCIE and IFI assays. ID test performed well till the end of the experiment (sensitivity and specificity: 100% and 90%, respectively). Both IFI and CCIE assays had a sensitivity of 40% and 20%, respectively for early detection of antibody, which was less sensitive than ID but both assays were more specific (100%) than the ID assay. The lowest agreement was between ID and IFI tests (40.3%), whilst the highest was observed between CCIE and IFI tests (67.2%). Of the three evaluated methods, the ID test could be recommended for scientific and laboratory diagnosis of heterophyosis in naturally infected animals. However, since none of the investigated method are optimal (i.e, offers 100% specificity and sensitivity), the choice of test employed must depend on the aim of the study.     

Feasibility of a single-species quota system for management of the Malaysian multispecies purse-seine fishery

Malaysian fisheries employ multiple measures to improve management; however, not all are well-suited to the multispecies fisheries. As part of a pilot project, an individual quota system was introduced for the purse-seine fishery off the East Coast of Peninsular Malaysia (ECPM), but no assessment of this particular measure nor the feasibly of its implementation has been confirmed. Therefore, this study analysed spatial and temporal patterns of purse-seine fishing, by collecting catch composition data per landing and its fishing ground within three period fishery surveys between August 2017 and September 2018 at six different landing sites. Similarity and cluster analysis examined species composition and diversity to determine the feasibility of implementing a single-species quota system in this multispecies fishery. Some overlapped of indices results and minor difference in catch composition were found due to changes in spatial and temporal fishing activities. However, no specific spatial or temporal patterns were discernible as structuring the fishing grounds used by purse-seiners. The absence of patterns, using the available data, might be attributable to huge species aggregations and widely distributed and homogenously mixed fish stocks. Thus, it is likely impractical to manage species individually in such a multispecies fishery.     

Thermal,swelling and stability kinetics of chitosan based semi-interpenetrating network hydrogels

The present study is focused on studying the swelling kinetics, thermal and aqueous stabilities, and determination of various forms of water in the chitosan (CS) and polyacrylonitrile (PAN) blend and semi-interpenetrating polymer network (sIPN). CS/PAN blend hydrogel films were prepared by solution casting technique. The blend film with optimum swelling properties was selected for the synthesis of sIPN. CS in the blend was crosslinked with the vapors of Glutaraldehyde (GTA) to prepare sIPN. The fabricated CS/PAN blend and sIPN hydrogels films were characterized with Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA) and field emission scanning electron microscope (FESEM). The kinetics of swelling, bound and unbound waters and aqueous stability were determined experimentally. FESEM showed good miscibility between CS and PAN, FTIR showed no chemical interaction between CS and PAN; however, it did show a doublet for the sIPN, TGA showed improved thermal stability and swelling kinetic followed second order kinetics. The degree of swelling of the sIPN hydrogels samples at room temperature varied from ~2200 % (with a fair degree of stability (~30 %)) to ~1000 % (with high degree of aqueous stability (43 %)) with increase in the crosslinking time. The calculated unbound water (W_UB) max., for the blend was 52.3 % whereas for the bound (W_B) the max., was 41.9 %. However, for sIPN hydrogel films, the W_UB water decreased (max. 21.0 %) where as the W_B increased (max. 52.0 %). The decrease in W_UB and increase in the W_B is attributed to the formation of a compact structure and increase in the contact area between the water and polymers in sIPN hydrogels due to the induction of new water contacting point in these hydrogel films, respectively.     

Actions of quinolizidine alkaloids on Periplaneta americana nicotinic acetylcholine receptors

BACKGROUND: Botanical insecticides do not play a major role as crop protectants, but they are beneficial in some applications. The authors investigated the actions of naturally occurring alkaloids on insect nicotinic acetylcholine (ACh) receptors (nAChRs) by evaluating their abilities to inhibit specific binding of [³H]imidacloprid (IMI) to nerve‐cord membranes from Periplaneta americana L. Two alkaloids were also tested for their actions on nAChRs expressed by cockroach neurons using patch‐clamp electrophysiology. RESULTS: Four natural quinolizidine alkaloids (matrine, sophocarpine, cytisine and aloperine) exhibited more than 50% inhibition of [³H]IMI binding at 10 µM , although other compounds were found to have no or low inhibitory activity. The rank order of potency based on concentration–inhibition curves was cytisine > sophocarpine ≥ aloperine ≥ matrine. Patch‐clamp analysis indicated that sophocarpine and aloperine were not agonists of nAChRs expressed in P. americana neurons, yet, at 10 µM , aloperine, but not sophocarpine, suppressed ACh‐induced inward currents significantly. CONCLUSION: Three of the four natural alkaloids tested possess structural moieties that are necessary for interaction with P. americana nAChRs. Aloperine, which possesses a unique structure and showed a distinctive dose–response curve, was found to act as an antagonist. Appropriate modifications of these alkaloids might result in novel insecticidal nAChR ligands. Copyright © 2008 Society of Chemical Industry     

Electrochemical Production of Ferrate (Iron VI): Application to the Wastewater Treatment on a Laboratory Scale and Comparison with Iron (III) Coagulant

This paper presents a comparative study of the performance of ferrate(VI), FeO ₄ ^2? , and ferric, Fe(III), towards wastewater treatment. The ferrate(VI) was produced by electrochemical synthesis, using steel electrodes in a 16 M NaOH solution. Domestic wastewater collected from Hailsham North Wastewater Treatment Works was treated with ferrate(VI) and ferric sulphate (Fe(III)). Samples were analysed for suspended solids, chemical oxygen demand (COD), biochemical oxygen demand (BOD) and P removal. Results for low doses of Fe(VI) were validated via a reproducibility study. Removal of phosphorous reached 40% with a Fe(VI) dose as low as 0.01 mg/L compared to 25% removal with 10 mg/L of Fe(III). For lower doses (<1 mg/L as Fe), Fe(VI) can achieve between 60% and 80% removals of SS and COD, but Fe(III) performed even not as well as the control sample where no iron chemical was dosed. The ferrate solution was found to be stable for a maximum of 50 min, beyond which Fe(VI) is reduced to less oxidant species. This provided the maximum allowed storage time of the electrochemically produced ferrate(VI) solution. Results demonstrated that low addition of ferrate(VI) leads to good removal of P, BOD, COD and suspended solids from wastewater compared to ferric addition and further studies could bring an optimisation of the dosage and treatment.     

Performance of Bangladesh indigenous rice in a weed infested field and separation of allelopathy from resource competition

This study aimed to identify the potential allelopathic indigenous rice (Oryza sativa L. ssp. indica) varieties from Bangladesh using a performance study in a weed‐infested field and to assess the extent of allelopathic interference relative to resource competition in a glasshouse experiment. Six varieties – namely, “Boterswar,” “Goria,” “Biron” and “Kartiksail” as the most allelopathic, “Hashikolmi” as weakly allelopathic and “Holoi” as nonallelopathic – were raised following a nonweed control method. The infestation levels of weed species were calculated using Simpson's Diversity Index (SDI), which ranged from 0.2 to 0.56. However, a significant correlation coefficient (0.87, P < 0.001) was obtained from these field data compared with the root inhibition percentage from the laboratory bioassay, and the “Boterswar” variety was the most allelopathic. The interactions between the allelopathic variety “Boterswar,” weakly allelopathic variety “Hashikolmi” and Echinochloa oryzicola via a target (rice)‐adjacent (E. oryzicola) cogrowth culture were determined in a hydroponic arrangement. The relative competitive intensity (RCI) and the relative neighbor effect (RNE) values showed that the crop–weed interaction was facilitation for “Boterswar” and competition for “Hashikolmi” and E. oryzicola in rice/E. oryzicola cogrowth cultures. The allelopathic effects of “Boterswar” were much higher than the resource competition in rice/E. oryzicola cogrowth cultures. The converse was observed for “Hashikolmi.” Moreover, the mineral content of E. oryzicola was severely affected by “Boterswar”/E. oryzicola cogrowth cultures’ exudate solution. Therefore, the allelopathic potential of “Boterswar” variety might be useful for developing the weed‐suppressing capacity of rice, which will likely have a significant influence on paddy weed control.     

Effects of onion on serum uric acid levels and hepatic xanthine dehydrogenase/xanthine oxidase activities in hyperuricemic rats

The aim of this study was to investigate the effects of onion on serum uric acid levels and hepatic Xanthine Dehydrogenase/Xanthine Oxidase activities in normal and hyperuricemic rats. Hyperuricemia was induced by intraperitoneal injection of 250 mg kg(-1) potassium oxonate in rats. Oral administration of onion at 3.5 and 7.0 mg kg(-1) day(-1) for 7 days was able to reduce serum uric acid levels in hyperuricemic rats with no significant effects on the level of this compound in the normal animals. In addition, onion when tested in vivo on rat liver homogeneities elicited significant inhibitory actions on the Xanthine Dehydrogenase (XDH) and Xanthine Oxidase (XO) activities. This effect resulted less potent than that of allopurinol. However, the hypouricemic effect observed in the experimental animal did not seem to parallel the change in XDH and XO activities, implying that the onion might be acting via other mechanisms apart from simple inhibition of enzyme activities. Such hypouricemic action and enzyme inhibitory activity of onion makes it a possible alternative for allopurinol, or at least in combination therapy to minimize the side-effects of allopurinol, in particular in long-term application.     

Potential associations between fecal shedding of Salmonella in feedlot cattle treated for apparent respiratory disease and subsequent adverse health outcomes

A prospective cohort study was used to assess whether Salmonella fecal shedding in commercial feedlot cattle treated with antimicrobials for respiratory disease was associated with subsequent adverse health outcomes. Feces were collected per rectum from cattle that were examined for apparent respiratory disease, had a rectal temperature > or = 40 degrees C, and subsequently received antimicrobial treatment. Salmonella were recovered from 918 (73.7%) of 1 245 fecal samples and weekly prevalence estimates ranged from 49 to 100% over the 3-month study. Genotypic and phenotypic characteristics of Salmonella strains in the population were determined. Serogroup E Salmonella were most common (73.3%), followed by C1 (11.0%), C3 (8.6%), and B (1.1%). Predominant serotypes were Orion (46.5%), Anatum (19.8%), Kentucky (8.7%), Montevideo (7.5%), and Senftenberg (4.9%). Few isolates (36/918) were positive for antimicrobial resistance-associated integron gene intI1. Phenotypic susceptibility was associated with isolate intI1 status. Crude re-pull, re-treatment and case fatality risks were higher for cattle that were Salmonella-positive versus -negative at initial treatment, but not statistically different on multivariable analysis. However, case fatality risk was higher for cattle shedding Group B Salmonella than for cattle shedding other serogroups. Lots (groups) with a higher Salmonella prevalence at first treatment had a higher proportion of mortalities occur in a hospital pen, higher overall re-treatment risks, and were more likely to be sampled later in the study. Results indicate a high prevalence of Salmonella in this population of cattle treated for apparent respiratory disease, but that effects associated with clinical outcomes may depend on the Salmonella strain.