Salinity and temperature effects on productivity of a tropical calanoid copepod Pseudodiaptomus incisus

Pseudodiaptomus species are major live feeds for the early stages of economically important marine fish in hatcheries in the South China Sea. However, we know little about the combined effects of multiple environmental parameters such as salinity and temperature on copepod productivity. To address the issue, we cultured a tropical coastal copepod Pseudodiaptomus incisus in one of 24 combinations of 8 salinities (5, 10, 15, 20, 25, 30, 35 and 40 ppt) and 3 temperatures (26, 30 and 34°C). We determined development, biomass of all stages, fecundity, percentage of females with hatched eggs and 30 hr nauplii production. Overall, the biomass, fecundity and nauplii production of P. incisus were highest at the salinity of 15–20 ppt, especially at 26°C. P. incisus showed a lower performance at both lower and higher salinities. Elevated temperatures resulted in faster development, but lower biomass, fecundity and nauplii production. Especially, nauplii production was reduced by 74% at 35–40 ppt and 34°C compared to at 15–20 ppt and 26°C. Our study provides essential information for optimizing the biomass culture of P. incisus.     

Effects of size and nitrite exposure on respiration,oxygen partitioning,and growth of obligate air-breathing fish Channa striata

The effects of fish size and nitrite level on metabolic rate and growth were investigated in the obligate air-breathing snakehead Channa striata, which is an important aquaculture species in Vietnam. Channa striata displayed respiratory size dependence, whereby the standard metabolic rate (SMR) and routine metabolic rate (RMR) decreased progressively in an exponential manner as fish size increased from 50 to 200 g. A mildly elevated nitrite level of 5% of the LC₅₀ 96 h (12 mg NO₂^?/L or safe concentration) induced significant increases in Channa striata SMR and RMR, which were almost double that of the control at the same size. At mild elevation, nitrite caused no significant effect on fish growth and survival during 3 months of rearing. However, both growth and survival rates of fish reared at severely elevated nitrite levels were significantly lower than those of the control; in particular, survival rates were under 50%. While changes in size reduced SMR and RMR, the percentage of air oxygen partitioning remained unchanged. Channa striata upregulation of SMR and RMR and air-breathing regulation were not significantly proven in this study. In summary, maintaining water environments at levels lower than 12 mg NO₂^?/L with ample oxygenation will not affect the growth and survival rate of snakeheads.

     

In situ micro-spectrophotometric and micro- spectrocolorimetric investigation of vacuolar pigments in flowers of cultivars of carnation (.Dianthus caryophyllus)

Living epidermal cells of flower petals of carnations have been surveyed for their native colour by in situ spectral (350-750 nm wavelengths) and colorimetric investigations (CIE- Lab, L* C* h system) of their vacuolar pigment content with a micro-spectrophotometer. Vacuolar solutions in cultivars with yellow based colours generally display high Absorbances (close to, or over A = 2 under a 25 |xm optical depth) in the near-UV area only: at 360-375 nm for ivory or pale yellow colours (flavonols only) and additionally at 380- 395 nm (chalcone glycosides) for yellow ones. Carnation cultivars with cyanic colours are accumulating anthocyanins, namely monosides and diosides of pelargonidin and cyani- din, along with flavonol glycosides acting as co-pigments. Besides their main À.max in the 520-550 nm area, frequently appearing at lower wavelengths than in those of diosides, spectra of solutions of monosides are characterized by an additional peak or shoulder around 450 nm. Cyanidin derivates often exhibit higher X.max wavelengths than those recorded in spectra of corresponding pelargonidin derivates. In the spectra of solutions of most classes of these anthocyanins, the visible Xmax position varies considerably, according to the relative concentrations of pigment (measured as the Absorbance at the visible Àmax) to co-pigment (appreciated by the Absorbance at the near-UV Xmax): generally, the higher this ratio, the longer is the visible Xraax wavelength. In situ spectral recording of individual vacuolar sap also reveals that different cells in the same petal epidermis are accumulating, in some cultivars, distinct pigment mixtures (diosides vs. monosides for instance) originating different colours. Colours of the vacuolar solutions have been colorimetrically described in the CIELab system in terms of hue (hab), saturation (Chroma, C*) and intensity (Lightness, L*). Generally, as the Absorbance at X.max, i.e. the pigment concentration, increases, Lightness decreases accordingly. Chroma mainly depends on the general shape of the spectra in the visible area. The more complex relationships of hue with spectral characteristics and the nature of the pigment mixture are discussed. Finally, the comparison of L* C* h colorimetric data calculated for two CIE illuminants (D65 and A) shows how the same pigment mixture (and consequently the further colour of intacts petals) appears to be coloured differently according to the lighting conditions of the visual observation.     

Effect of Vermicompost in Media on Growth,Yield and Fruit Quality of Cherry Tomato (Lycopersicon esculentun Mill.) Under Net House Conditions

Effects of VC application on tomato production and media properties can last for the third successive season, which was verified in this study to evaluate effects of VC application on growth, productivity and fruit quality of cherry tomato for the third season. Six treatments were designed similarly in the first and second seasons (unchanged design compared to the previous season), including: VC with rice husk ash (RHS) and coconut fiber (CF) 0% VC+ 50% RHS +50% CF (T1- control), respectively. 20%VC + 40% RHS + 40% CF(T2), 40% VC+ 30% RHS + 30% CF(T3), 60% VC + 20% RHS + 20% CF(T4), 80% VC + 10% RHS + 10% CF(T5), and 100% VC(T6). The results showed that the pH, EC, N, P, K, Ca, and Mg available in media were increased with the addition of VC. This finding revealed that the addition of VC significantly improved the physic-chemical media properties, increasing the EC and also increasing the macronutrients in the media resulting in substantial increased the yield and quality of tomato fruits. It is concluded that EC of VC was the key factor for the positive increase of the productivity and quality of tomato and the salinity (EC at 3.52 dS/m) causing restriction of water to fruits that resulted in the increase of the total soluble solids in tomato fruit and without affecting yield reduction.     

Combining rainfall–runoff and hydrodynamic models for simulating flow under the impact of climate change to the lower Sai Gon-Dong Nai River basin

This study presented simulation results of runoff discharge combining the Mike NAM and Mike SHE models for lower Sai Gon-Dong Nai River basin (SG-DNRB). Sai Gon-Dong Nai River basin is Vietnam’s largest population center and main industrial area in Ho Chi Minh City. In recent years, the area faces flooding problems because of heavy rainfalls and high tides, as part of the impacts of climate change and sea level rise. The lower of SG-DNRB was selected as a case study to highlight the necessity to investigate combination of the rainfall–runoff model and the hydrodynamic model for long-term strategies to resource water in the future. The models were calibrated using water level and runoff discharge data during low and flood seasons in 2014. The calibrated results showed satisfactory coefficients (NASH index, R² up to 0.70 and RMSE is smaller than 0.20). The results confirmed that the combination of Mike NAM and Mike SHE models is well suitable to simulate runoff discharge in the lower SG-DNRB. Combination of the models can be considered a useful tool to help professional agency operator water resources management projects in other areas in the context of climate change and sea level rise.     

The role of rpoS,hmp, and ssrAB in Salmonella enterica Gallinarum and evaluation of a triple-deletion mutant as a live vaccine candidate in Lohmann layer chickens

Salmonella enterica Gallinarum (SG) causes fowl typhoid (FT), a septicemic disease in avian species. We constructed deletion mutants lacking the stress sigma factor RpoS, the nitric oxide (NO)-detoxifying flavohemoglobin Hmp, and the SsrA/SsrB regulator to confirm the functions of these factors in SG. All gene products were fully functional in wild-type (WT) SG whereas mutants harboring single mutations or a combination of rpoS, hmp, and ssrAB mutations showed hypersusceptibility to H₂O₂, loss of NO metabolism, and absence of Salmonella pathogenicity island (SPI)-2 expression, respectively. A triple-deletion mutant, SGΔ3 (SGΔrpoSΔhmpΔssrAB), was evaluated for attenuated virulence and protection efficacy in two-week-old Lohmann layer chickens. The SGΔ3 mutant did not cause any mortality after inoculation with either 1 × 10⁶ or 1 × 10⁸ colony-forming units (CFUs) of bacteria. Significantly lower numbers of salmonellae were recovered from the liver and spleen of chickens inoculated with the SGΔ3 mutant compared to chickens inoculated with WT SG. Vaccination with the SGΔ3 mutant conferred complete protection against challenge with virulent SG on the chickens comparable to the group vaccinated with a conventional vaccine strain, SG9R. Overall, these results indicate that SGΔ3 could be a promising candidate for a live Salmonella vaccine against FT.     

Diagnostic value of recombinant nanoluciferase fused Toxoplasma gondii antigens in Luciferase-linked Antibody Capture Assay (LACA) for Toxoplasma infection in pigs

Toxoplasmosis is a widespread protozoan zoonosis. Since ingesting undercooked meat harboring Toxoplasma gondii cyst is considered one of the major transmission routes to humans, the screening of T. gondii in meat-producing animals can reduce the risk of food-borne toxoplasmosis in humans. Among serological diagnostic methods, Luciferase-linked Antibody Capture Assay (LACA) has been found to be a promising platform with high sensitivity and specificity. In this study, we aimed to evaluate recombinant nanoluciferase fused-T. gondii antigens (rNluc-GRA6, rNluc-GRA7, rNluc-GRA8 and rNluc-BAG1) for their potential use in LACA for pigs. As a result, the sensitivity of GRA6-, GRA7-, GRA8- and BAG1-LACA were 70.0%, 80.0%, 80.0% and 30.0% with specificity 87.0%, 81.5%, 74.1% and 50.0%, respectively. The cocktail LACA using a mixture of rNluc-GRA6, rNluc-GRA7 and rNluc-GRA8 indicated higher sensitivity (90.0%) and a similar specificity (96.3%) in comparison with the commercial ELISA kit. Compared to the Dye-Test as a reference test, cocktail LACA showed strong agreement (kappa value=0.811) when we assessed pig sera collected at the slaughterhouse. In addition, we also successfully established the rapid LACA format for the detection of Toxoplasma infection in pigs (called Rapid-LACA) in which the test could be performed within 30 min. In Rapid-LACA, the protein A pre-coated/blocked plates could be preserved at −30°C, 4°C or room temperature conditions for at least two months without compromising on the quality of assay.     

Three‐dimensional CT observation of position and movability of the scapula in the horse using carcasses of Falabella

The three‐dimensionally real position and movement of the scapula in the lateral side of the ribcage could not be clarified in the horse, since the body size of the horse is too large to apply the CT scanning and image analysis methods. In this study, therefore, we examined the position and the movability of scapula using a carcass of the Falabella which is one of the smallest breeds of the horse. The whole skeletal system in thoracic part of the Falabella could be three‐dimensionally observed by CT scanning method. The three‐dimensional images show that the scapula cranially slides and the ventral part of the scapula dorso‐cranially rotates, when the shoulder joint moves to the most cranial position as simulation. The three‐dimensional rotation angle was approximately 10 degrees. As a result of comparative osteology of the scapula between Falabella and the large draft horse, the infraspinous fossa was caudally enlarged in the larger draft horse, whereas the Falabella had narrower infraspinous fossa. We suggest that it may be due to the adaptational morphological change in the scapula bearing various body weights among breeds. The three‐dimensional CT image analysis and the simulation in carcass contribute to the analysis of the bone movements of the horse during walking and running locomotion as well as the motion analysis from external functional‐morphological data.     

Resistance in field pea (Pisum sativum) to the black spot disease complex in Western Australia

Black spot (also referred as Ascochyta blight, Ascochyta foot rot and black stem; Ascochyta leaf and pod spot) is a devastating disease of field pea (Pisum sativum) caused by one or more pathogenic fungi including Didymella pinodes, Ascochyta pisi, Phoma pinodella and P. koolunga. Development of resistant germplasm has been slow because of the low level of resistance found in the available germplasm, poor reliability of screening methods and the polygenic nature of inheritance. Field studies, undertaken to assess F8 and F9 derived lines for resistance against the black spot complex, confirmed that some lines developed in the Australian breeding program show improvement in resistance over commercial cultivars. Disease scores across test lines ranged from 5.33 to 7.82 (0–9 scale where 0?=?no disease symptoms, and 9?≥?90 % leaf area affected) and from 5.37 to 8 in 2012 and 2013, respectively. In 2012, the eight most resistant lines had scores 5.33 to 6, with OZP1207 the most resistant line. In 2012, forty three lines were significantly more resistant (disease score?≤?6.67) than the susceptible standard, Helena (7.82), 14 lines were not significantly different to the most resistant commercial cultivar, Parafield (6.33), and 27 lines were significantly more resistant than PBA Percy (7.67). In 2013, WAPEA2211 was clearly the most resistant line (5.37) followed by a group of seven lines with slightly less resistance scored at 6. Use of these lines in breeding will further enhance resistance in commercial cultivars, particularly by inter-crossing among the more genetically diverse lines to accumulate minor genes for resistance. While there was no overall relationship between disease scores in 2012 and 2013 (R ²?=?0.029), presumably due to the highly variable pathogen composition of the black spot complex at the screening site and across seasons in Western Australia, a few lines, such as WAPEA2211, 04H349P-05HO2005, 06H109P-9 and 06H459P-1, showed significant resistance in both years, appear to have resistance to multiple pathogens in the black spot complex, and are of particular significance.