Preharvest applications of growth regulators and their effect on postharvest quality of table grapes during cold storage

Over 54,600 ha of table grapes (Vitis vinifera), mainly cvs. ‘Thompson Seedless’, ‘Flame Seedless’ and ‘Redglobe’, are planted in Chile. Almost the entire production is exported to the USA, Europe, Asia, or one of several Latin American countries, which typically requires 15–40 d of maritime transportation. During this period, several physical, physiological, and pathological factors cause table grape deterioration. Because berry size is the main quality factor in international markets, farmers often overuse the growth regulators, gibberellic acid (GA₃) and forchlorfenuron (CPPU), in an effort to increase berry size. We examined the effect of preharvest growth regulators on seedless (‘Thompson Seedless’, and ‘Ruby Seedless’) and seeded (‘Redglobe’) table grape cultivars during cold (0 °C) storage plus a shelf life period of 3 d at 20 °C. The overuse of GA₃, eight instead of two GA₃ applications on Thompson Seedless, and the use of one GA₃ application on Redglobe and ‘Ruby Seedless’, increased berry pedicel thickness and lowered cuticle content but induced shatter and predisposed grapes to gray mold caused by Botrytis cinerea. In contrast, CPPU increased berry pedicel thickness and cuticle content but did not increase shatter or gray mold incidence. Clusters that were subjected to overuse of combined GA₃ and CPPU were highly sensitive to shatter, had the thickest pedicel, and developed a high gray mold incidence during cold storage. Hairline, a fine cracking developed during cold storage, was induced on ‘Thompson Seedless’ and ‘Ruby Seedless’ by growth regulators, but no hairline occurred on ‘Redglobe’ table grapes. Therefore, berry quality during cold storage is greatly influenced by growth regulator management in the vineyard.     

Caprine toxoplasmosis in Southern Brazil: a comparative seroepidemiological study between the indirect immunofluorescence assay,the enzyme-linked immunosorbent assay,and the modified agglutination test

Tropical Animal Health and Production - This study investigated the prevalence of caprine toxoplasmosis in goat herds from Southern Brazil by the indirect immunofluorescence assay (IFA), and...     

Optimizing injection time of GFP plasmid into sheep zygote

Microinjection of exogenous DNA into the cytoplasm of matured oocytes or zygotes is a promising technique to generate transgenic animals. However, the data about the microinjection time and procedure in sheep are limited and have not treated in detail. To obtain more in-depth information, the Sarda sheep oocytes from abattoir-derived ovaries were subjected to IVM and IVF. Then, the GFP plasmid as a reporter gene was injected into the cytoplasm of MII oocytes (n: 95) and zygotes at different post-insemination intervals (6–8 hpi, n: 120; 8–10 hpi, n: 122; 10–12 hpi, n: 110 and 12–14 hpi, n: 96). There were no significant differences in the cleavage rates between the groups. However, blastocyst rate of injected zygotes at all-time intervals was significantly lower than injected MII oocytes and control group (p < 0.05). Interestingly, the proportion of GFP-positive embryos was higher at 8–10 hpi compared with other injected groups (4 % versus 0 %, p  < 0.01). Among these, the proportion of mosaic embryos was high and two of those embryos developed to the blastocyst stage. In conclusion, we settled on the cytoplasmic microinjection of GFP plasmid at 8–10 hpi as an optimized time point for the production of transgenic sheep and subsequent experiments.     

Molecular cloning,purification and immunogenicity of recombinant Brucella abortus 544 malate dehydrogenase protein

The Brucella mdh gene was successfully cloned and expressed in E. coli. The purified recombinant malate dehydrogenase protein (rMDH) was reactive to Brucella-positive bovine serum in the early stage, but not reactive in the middle or late stage, and was reactive to Brucella-positive mouse serum in the late stage, but not in the early or middle stage of infection. In addition, rMDH did not react with Brucella-negative bovine or mouse sera. These results suggest that rMDH has the potential for use as a specific antigen in serological diagnosis for early detection of bovine brucellosis.     

The effects of temperature and photoperiod on egg hatching success,egg production and population growth of the calanoid copepod,Acartia grani (Calanoida: Acartiidae)

Calanoid copepods, including species of the genus Acartia, are commonly used as larval diets for marine finfish. This study aimed to determine the separate effects of water temperature (18, 22, 24, 28° ± 0.5°C) and photoperiod (24L:0D; 18L:6D; 12L:12D; 8L:18D; 0L:24D) on Acartia grani egg production (EP), hatching rate (EHR) and population growth. Egg production rate was not affected by the two abiotic parameters. A. grani eggs incubated at T24°C and T28°C were the first to achieve 50% hatching rate (23–25 hr), with significant differences at the end of the experiment (48 hr) between T28°C treatment (EHR 88 ± 5%) and T18°C treatment (EHR 65 ± 2%). However, different temperature regimes did not affect final number of individuals in population growth experiment. Still, when eggs were excluded from data, population at lower temperatures (18°C) was mainly composed by the nauplii stage (72%), while at higher temperatures (24°C and 28°C) more than 60% of the population was composed by copepodites and adults. A. grani subjected to long‐day photoperiods had significantly lower EHR (16.7% at 24L:0D; 20.8% at 18L:6D) than at short‐day photoperiods (52.6% at 6L:18D; 50.0% at 0L:24D). In population growth experiment, eggs were the most common life stage after 12‐day culture. Lowest population number was found at constant light conditions (665.0 ± 197.1), suggesting higher metabolic rates and depletion of energy reserves in long‐day conditions. This study expanded knowledge on the biological response of A. grani to separate temperature and photoperiod regimes, and provided ground to improve the culture of this potential life feed species for hatcheries.     

Disseminated pythiosis in three horses

Three cases of equine subcutaneous pythiosis with dissemination to the internal organs were investigated. The subcutaneous lesions were observed on the mammary gland, nostrils and limbs of the infected horses. Histopathological analysis of the infected tissues revealed a strong eosinophilic reaction, with macrophages, mast cells and giant cells. Sparsely septated hyphal filaments of 4-6 microm diameter were identified in the center of the eosinophilic areas. Specific fluorescent antibody against Pythium insidiosum confirmed the hyphae in the infected tissues in three examined horses. In one of the three cases, the DNA sequences amplified from the infected subcutaneous tissues and internal organs, revealed that P. insidiosum's 18S SSU rDNA amplicons shared 100% identity with those sequences deposit in GenBank. This is the first report confirming by immunochemical and genetic techniques that P. insidiosum can disseminated from superficial to deep structures.     

Characterization of culture supernatant proteins from Brucella abortus and its protection effects against murine brucellosis

In this study, we characterized the secreted proteins of Brucella abortus into the enriched media under the bacterial laboratory growth condition and investigated the pathogenic importance of culture supernatant (CS) proteins to B. abortus infection. CS proteins from stationary phase were concentrated and analyzed using 2D electrophoresis. In MALDI TOF/TOF analysis, more than 27 proteins including CuZn SOD, Dps, Tat, OMPs, Adh, LivF, Tuf, SucC, GroEL and DnaK were identified. Cytotoxic effects of CS proteins were found to increase in a dose-dependent manner in RAW 264.7 cells. Upon B. abortus challenge into phagocytes, however, CS proteins pre-treated cells exhibited lower bacterial uptake and intracellular replication compared to untreated cells. Immunization with CS proteins induced a strong humoral and cell mediated immune responses and exhibited significant higher degree of protection against virulence of B. abortus infection compared to mice immunized with Brucella broth protein (BBP). Taken together, these results indicate that B. abortus secreted a number of soluble immunogenic proteins under laboratory culture condition, which can promote antibody production resulted in enhancing host defense against to subsequently bacterial infection. Moreover, further analysis of CS proteins may help to understand the pathogenic mechanism of B. abortus infection and host–pathogen interaction.     

Survival of silver catfish fingerlings exposed to acute changes of water pH and hardness

Theaim of this study was to examine the survival of fingerlings of silver catfish,Rhamdia quelen, in water with different pH and hardnessvalues. Fingerlings (1.60 ± 0.14 g; 5.67 ± 0.15cm) were randomly assigned to 35 treatments (in triplicate) andmaintained in 44 L polyethylene tanks (10 fingerlings/tank) for 96h. Fingerlings were exposed to seven solutions of varying pH (3.5,3.75, 4.0, 7.0, 9.5, 10.0, and 10.5) and five solutions of varying hardness(30,70, 150, 300, and 600 mg.l^?1 CaCO₃).Survival was assessed at 12, 24, 48, 72, and 96 h. Fingerlingmortality was 100% after 12 h exposure to pH 3.5 at all hardnesslevels, whereas mortality at pH 3.75, 10.0, and 10.5 decreased with increasinghardness. There was no mortality of fingerlings exposed to pH 4.0, 7.0, and 9.5at all hardness levels. The results allow us to conclude that the hardnesslevels studied do not affect the survival of silver catfish fingerlings exposedto pH 3.5, 4.0, 7.0, and 9.5 for 96 h. However, the increase ofwater hardness improved survival of fingerlings of this species exposed to pH3.75, 10.0, and 10.5.