Dietary fulvic acid effects on survival and expression of immune‐related genes in Litopenaeus vannamei challenged with Vibrio parahaemolyticus

The effects of fulvic acid (FA) on survival and immune‐related gene expression were investigated in Litopenaeus vannamei challenged with Vibrio parahaemolyticus by immersion. Shrimp were fed with different dietary FA concentrations (1, 2, 4 and 6 g/kg feed) for 20 days (first bioassay) or 8 days (second bioassay, 2 g/kg feed of FA added every 2 days) and then challenged with V. parahaemolyticus. In a third bioassay, the expression of three immune‐related genes (translationally controlled tumour protein [TCTP], superoxide dismutase [SOD] and heat‐shock protein 70 [HSP70]) in haemocytes or hepatopancreas of experimental shrimp was measured by real‐time quantitative PCR at 0, 6, 12, 24, 48, 72 and 96 hr after FA (2 g/kg feed) administration. Fulvic acid increased survival at a concentration of 2 g/kg feed supplied every two days. Interestingly, TCTP gene expression was upregulated, whereas gene expression of SOD and HSP70 was downregulated. In conclusion, dietary fulvic acid improves survival in white shrimp challenged with V. parahaemolyticus and modulates the immune response. Therefore, FA merits further evaluation as prophylactic treatment in commercial shrimp farms.     

Effect of Storage Time on In Vitro Digestibility and Resistant Starch Content of Nixtamal,Masa, and Tortilla

Nixtamal, masa, and tortilla samples were stored for 24–96 hr and their chemical composition, retrogradation, and in vitro starch digestibility features were evaluated. Ash and fat contents in the three products were smaller than in the original corn sample, but protein levels were higher, all in accordance with previous studies. In general, a minor decrease in available starch (AS) content was observed with storage time. Masa showed the greatest AS values, followed by tortilla and nixtamal. Tortilla presented slightly higher retrograded resistant starch (RS3) values (1.1–1.8%, dmb) than masa (0.7–0.9%) and nixtamal (0.7–0.8%) and only minor increases were observed after 24 hr of storage, suggesting that retrogradation phenomenon in these samples takes place very rapidly and is more pronounced in the final product (tortilla). The development of RS3 explains the observed decrease in AS. Higher total resistant starch values were found in all samples at a range of 2.1–2.6% for nixtamal and masa, and a range of 3.1–3.9% in tortilla. This indicates that, apart from retrograded resistant starch, some ungelatinized fractions appear to contibute to the indigestible content of these products. The α‐amylolysis rate of the three materials decreased with storage. Tortilla showed the greatest hydrolysis indices. Differential scanning calorimetry (DSC) analysis showed that the nixtamal, masa, and tortilla did not show differences in amylopectin crystal melting temperature with storage time, but tortilla exhibited higher enthalpy values after 72 hr of storage, in accordance with the greater total RS contents recorded after prolonged storage.     

概率配点法在流域非点源污染不确定性分析中的应用

农业非点源污染的形势十分严峻,流域水环境模型虽能为非点源污染管理提供决策支撑,但显著的不确定性制约着模型的应用效果.系统的不确定性分析十分重要,而传统的基于Monte Cado模拟的小确定性分析方法存在着计算成本高昂的缺点.因此,尝试将概率配点法(Probabilistic Collocation Method)应用于流域非点源污染的小确定性分析.研究以美国Newport Bay流域的二嗪磷农药非点源污染为案例,利用WARMF模型进行污染模拟.结果表明,在许多情况下,概率配点法可以通过很小的计算成本获得与传统Monte Carlo模拟方法相近的不确定性分析结果,体现出该方法在非点源污染研究中应用的优势.此外,还揭示了管理因素对于非点源污染模拟及其不确定性分析的影响作用.     

Landscape-mediated edge effect in temperate deciduous forest: implications for oak regeneration

Context

Although the edge effect is known to be an important factor influencing the recruitment of trees in temperate forests, little is known of its synergistic relationships with landscape and fragment attributes.

Objectives

We investigated how the edge effect on regeneration of oaks (Quercus spp.) varies with respect to fragment geometry, connectivity and landscape composition.

Methods

We recorded oak sapling density along edge-interior gradients in 29 forest fragments at the periphery of Mexico City and examined the data with Generalized Additive Models.

Results

A nonlinear and landscape-mediated edge effect was supported by data, including the interactions of the edge distance with patch connectivity, shape and size. Saplings were more abundant at a distance of ca. 50 m from the edge of small, large and connected patches, but large patches also exhibited reduced recruitment towards the interior of the patch. Conversely, sapling density in simple-shaped or connected patches was lower at the edge, exhibiting linear and concave-down increase trends towards the interior of patches, respectively.

Conclusions

Boundary conditions could be interacting with interior forest conditions, making regeneration more frequent at 50 m from the edge. Shady and cooler sites in large patches may be inhibiting oak regeneration. The activity of acorn-dispersing animals and oak predators may increase in unconnected patches, thus increasing the likelihood of edge effects. These results provide insights into the restoration of temperate forest patches in heterogeneous fragmented landscapes.

     

Heat Flux Measurements and Modeling of Malodorous Compounds above an Anaerobic Swine Lagoon

The number of chemical compounds in sewage and consequently their release into the environment is increasing. Some of them are toxic and many of them are considered endocrine disrupters. Here, the capacity of three wastewater treatment plants (WWTPs) to remove caffeine, hormones and bisphenol-A was investigated. Bisphenol-A and caffeine are highly water-soluble compounds, as opposed to hormones (estradiol, estriol, and ethynilestradiol) which are hydrophobic compounds. In the Sewage Treatment Plant (SWT)1 the sewage is treated by activated sludge process, in the second plant, SWT2, sewage is treated by upflow anaerobic sludge blanket reactors followed by dissolved air flotation, and in the third, SWT3 sewage is treated by stabilization lagoons. The first lagoon is 3.5 m deep, thus facultative and polishment processes occur. It was speculated that there was a difference in efficiency between the three plants in removing micropollutants. Small differences were found in the amounts removed, probably accounted for by retention time. The caffeine and bisphenol-A were almost completely removed, higher than 90% for both compounds (bisphenol-A and caffeine) in all WWTPs. The hormones, however, had a smaller rate of removal, between 70% and 87%. It is suspected that retention time is essential for removal efficiency, together with type of treatment. In fact, the hormones, caffeine, and bisphenol-A found in the environment definitely come from untreated sewage.     

Hemagglutinin serotyping of <Emphasis Type="Italic">Avibacterium paragallinarum</Emphasis> isolates from Ecuador

Avibacterium paragallinarum is the causative agent of infectious coryza, an acute respiratory disease of chickens. In this study, a total of 28 isolates of A. paragallinarum from Ecuador were serotyped by the hemagglutinin scheme which recognizes nine serovars. Out of 28 isolates, 17 isolates belonged to serovar A-3, and five isolates to each serovars B-1 and C-1, whereas one isolate was non-typeable. This is the first report of A. paragallinarum serovar A-3 outside Brazil and serovar C-1 outside Japan.     

Use of neuromuscular blockade with rocuronium bromide for intubation in cats

ObjectiveTo determine whether neuromuscular blockade with rocuronium bromide (RB) would improve endotracheal intubation (EI) conditions in comparison with topical lidocaine hydrochloride (LH).Study designRandomized prospective study.AnimalsForty seven healthy cats of unspecified breed, aged 17 ± 11 months and weighing 2.8 ± 0.8 kg, undergoing elective procedures.MethodsAnesthesia was induced with xylazine (XZ) (1.1 mg kg^?1 IM) and tiletamine‐zolazepam (XTZ) (7 mg kg^?1 IM) and EI was attempted. Cats which could not be intubated at the first attempt (n = 34), were randomly medicated with either 0.1 mL LH 10% spray on the laryngeal mucosa (n = 17) or 0.6 mg kg^?1 intravenous RB (n = 17). Sixty seconds later, a second attempt at EI was performed. The effect of both drugs was assessed using a previously published scale (Sandor Agoston). EI conditions associated with laryngoscopy, vocal cord position and movement, cough, patient movement, time and attempts needed in order to perform EI were recorded. Heart rate and end‐expired CO₂ concentration were monitored.ResultsGroups were comparable in age, weight, gender and hematological parameters. Clinically acceptable EI conditions were not significantly different between RB and LH assisted groups (p = 0.31). However, there was a significant difference in cough, vocal cord movement and position between the RB and the LH groups. The group intubated at the first attempt and receiving neither RB nor LH coughed persistently (11/13). The cats receiving RB had to be ventilated for 10–28 minutes.Conclusions and clinical relevanceThe present study shows that, when used in cats anesthetized with XTZ, RB paralyzes the internal laryngeal muscles keeping the vocal cords in an intermediate position (paramedial) 60 seconds after being administered. RB is an effective alternative to LH to overcome the airway protective reflexes when performing EI but requires ventilatory support until the paralysis wears off.     

Flaxseed (Linum usitatissimum L.) and Its Total Non-digestible Fraction Influence the Expression of Genes Involved in Azoxymethane-induced Colon Cancer in Rats

The influence of flaxseed (Linum usitatissimum L.) and its total non-digestible fraction (TNDF) on the expression of genes involved in azoxymethane (AOM)-induced colon cancer in Sprague Dawley rats was analyzed. The dose used in the animal model was two tablespoons of flaxseed per day, which is the dose recommended for humans. Flaxseed significantly decreased the crypt multiplicity (10.50?±?3.5) compared with the AOM treatment (34.00?±?11.0), which suggests that flaxseed exhibits a preventive effect against colon cancer. Both treatments (flaxseed and TNDF) influence the overexpression of genes involved in cell cycle arrest and mitochondrial apoptosis: p53, p21, bcl-2, bax and caspase-3. Flaxseed induced the expression of p53 and p21, whereas TNDF triggered the p21-independent expression of p53. This finding suggests that both of these treatments induced cell cycle arrest. In addition, TNDF induced mitochondrial apoptosis because the TNDF + AOM group exhibited the expression of caspase-3, decreased bcl-2 expression and increased bax expression. These results suggest that the expression of the analyzed genes is associated with the presence of dietary antioxidants linked to the cell wall of flaxseed.     

Solubilization Effects on Molecular Weights of Amylose and Amylopectins of Normal Maize and Barley Starches

Structural characteristics of starches have been important to determine their physicochemical and functional properties. Solubilization procedures were tested to find a higher solubilization percentage and thereafter to study the structural characteristics of amylose and amylopectin. Size‐exclusion chromatography with refractive index (SEC‐RI) system using a pullulan standard curve was tested to study the amylose molar mass. Also, a microbatch system using a MALLS detector was used to determine the molar mass and gyration radius of starch and amylopectin. Microwave heating produced higher solubility percentages than autoclaving, and there was a difference between both starches. The sample solubilized with microwave heating presented higher molar mass and gyration radius values than autoclave samples, showing that this process for structural studies provided information representative of the initial starch sample. When starch components were separated, amylose showed lower purity than amylopectin. Lower purity was obtained for amylose separated from barley starch, but no difference was obtained for purity of amylopectin separated from both starches. Barley amylopectin had a higher solubility percentage than maize amylopectin. Molar mass of barley amylose was 1.03 × 10⁵ g/mol and for maize of 2.25 × 10⁵ g/mol. Molar mass values of amylopectin separated from both starches were lower than the starch counterparts, although the same solubilization procedure (microwave heating) was used. The difference might be due to depolymerization during separation of starch components.