Effect of dips in a 1-methylcyclopropene-generating solution on 'Harrow Sun' plums stored under different temperature regimes     

Manganaris GA  Vicente AR  Crisosto CH  Labavitch JM 《Journal of agricultural and food chemistry》2007,55(17):7015-7020

The effect of postharvest dips in a 1-methylcyclopropene-generating solution of the formulation AFxRD-038 (Rohm & Haas) on plum fruit (Prunus salicina Lindell cv. 'Harrow Sun') quality and ripening during storage was determined. Fruit weight loss, tissue firmness, soluble solids content (SSC), titratable acidity (TA), ethylene production, respiration, and the activities of the cell wall modifying enzymes polygalacturonase (PG), 1,4-beta-D-glucanase/glucosidase (EGase), beta-galactosidase (beta-gal), and pectin methylesterase (PME) were measured. Fruit reddening, anthocyanin content, and phenylalanine ammonia-lyase (PAL) activity were also analyzed. The 1-MCP-treated fruit showed reduced ethylene production and respiration rate and delayed softening, which was associated with the reduction in the activity of PG, EGase, and beta-gal. The immersion in 1-MCP-generating solutions also decreased weight and acidity loss without modifying the fruit SSC. The immersion treatment was particularly effective in the fruit stored at 5 degrees C, keeping higher overall quality, maintaining lower levels of anthocyanins and PAL activity, and preventing flesh reddening. The present data show that beneficial effects in delaying plum fruit ripening and controlling chilling injury can be obtained by dipping the fruits in a solution of this novel 1-MCP-generating formulation.  相似文献   

Broccoli processing wastes as a source of peroxidase     

Duarte-Vázquez MA  García-Padilla S  García-Almendárez BE  Whitaker JR  Regalado C 《Journal of agricultural and food chemistry》2007,55(25):10396-10404

A peroxidase isozyme (BP) was purified to homogeneity from broccoli stems ( Brassica oleraceae var. maraton) discarded from industrial processing wastes. BP specific activity was 1216 ABTS [2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid)] units/mg, representing 466-fold that of crude extract. BP is a monomeric glycoprotein containing 16% carbohydrates, with a molecular mass of 49 kDa and an isoelectric point close to 4.2. From kinetic data it showed a two-substrate ping-pong mechanism, and the catalytic efficiency measured as the rate-limiting step of free BP regeneration was 3.4 x 10(6) M(-1) s(-1). The ABTS K m value was 0.2 mM, which was about 20 times lower than that reported for acidic commercial horseradish peroxidase (HRP). Assessment of BP secondary structure showed 30% helical character, similar to HRP and cytochrome c peroxidase. BP lost only 25% activity after 10 min of heating at 55 degrees C and pH 6; it was stable in the pH range from 4 to 9 and showed an optimum pH of 4.6 using ABTS as substrate. BP was active on substrates normally involved in lignin biosynthesis, such as caffeic and ferulic acids, and also displayed good catechol oxidation activity in the presence of hydrogen peroxide. Reverse micellar extraction was successfully used as potential large-scale prepurification of broccoli peroxidase, achieving a purification factor of 7, with 60% activity yield. Stems from the broccoli processing industry have a high potential as an alternative for peroxidase purification.  相似文献   

Osteomalacia as a result of phosphorus deficiency in beef cattle grazing subtropical native pastures in Uruguay     

Carlos O. Schild  Fabiana M. Boabaid  Luiz G.S. Olivera  Mizael Machado  Ana Vildoza  Anderson Saravia  Alejandra Custodio  Carolina Command  Agustín Martinez  Martín Jaurena  Rob Dixon  Franklin Riet-Correa 《Journal of veterinary diagnostic investigation》2021,33(5):1018

We investigated 2 outbreaks of osteomalacia as a result of phosphorus (P) deficiency in herds of lactating beef cows grazing subtropical native pastures in Uruguay. Cows exhibited pica, difficulty to stand and walk, rib fractures, and body weight loss even with adequate forage availability. Osteopenia and severe osteomalacia were observed on gross and histologic examination. The concentrations of bicarbonate-extractable P in soil (4.0, 4.1 mg P/kg), total P in pasture (0.9, 1.1 g P/kg), inorganic P in serum (1.0, 0.71 mmol P/L), and P in bone (73 mg P/mL) were all low. Although injectable and mineral salt supplements provided additional P in both outbreaks, these supplementary amounts were insufficient to prevent P deficiency. The P ingested by the cows from the pasture and supplements would have provided 20–55% of their daily P requirements of ~21 g P/d. Osteomalacia occurred in cattle at the 2 ranches as a result of severe P deficiency in the soil and forage, and inadequate P supplementation. Following diagnosis, control of P deficiency in beef cattle requires estimation of the amount of pasture P ingested and provision of sufficient additional supplementary P to meet the animals’ requirements.  相似文献   

Do different densities of tree cover affect pasture biomass and soil microbial communities?     

Neira  Pablo  Henríquez-Castillo  Carlos  Ortiz  Juan  Stolpe  Neal  Dube  Francis 《Agroforestry Systems》2021,95(8):1465-1478

Agroforestry Systems - Soil biota is considered a crucial component of soil health. Currently, the soil microbiota and its genomic material (microbiome) have received increasing attention due to...  相似文献   

Tomato mottle mosaic virus: Characterization,resistance gene effectiveness,and quintuplex RT-PCR detection system          下载免费PDF全文

Carlos Kwesi TETTEY  YAN Zhi-yong  MA Hua-yu  ZHAO Mei-sheng  GENG Chao  TIAN Yan-ping  LI Xiang-dong 《农业科学学报》2022,21(9):2641-2651

Tomato mottle mosaic virus (ToMMV), an economically important species of the genus Tobamovirus, causes significant loss in yield and quality of tomato fruits. Here, we identified the Shandong isolate of ToMMV (ToMMV-SD) collected from symptomatic tomato fruits in Weifang, Shandong Province of China. ToMMV-SD caused symptoms such as severe mosaic, mottling, and necrosis of tomato leaves, yellow spot and necrotic lesions on tomato fruits. The obtained full genome of ToMMV-SD was 6 399 nucleotides (accession number MW373515) and had the highest identity of 99.5% with that of isolate SC13-051 from the United States of America at the genomic level. The infectious clone of ToMMV-SD was constructed and induced clear mosaic and necrotic symptoms onto Nicotiana benthamiana leaves. Several commercial tomato cultivars, harboring Tm-2² resistance gene, and pepper cultivars, containing L resistance gene, were susceptible to ToMMV-SD. Plants of Solanum melongena (eggplant) and Brassica pekinensis (napa cabbage) showed mottling symptoms, while N. tabacum cv. Zhongyan 100 displayed latent infection. ToMMV-SD did not infect plants of N. tabacum cv. Xanthi NN, Brassica rapa ssp. chinensis (bok choy), Raphanus sativus (radish), Vigna unguiculata cv. Yuanzhong 28-2 (cowpea), or Tm-2² transgenic N. benthamiana. A quintuplex RT-PCR system differentiated ToMMV from tomato mosaic virus, tomato brown rugose fruit virus, tobacco mosaic virus, and tomato spotted wilt virus, with the threshold amount of 0.02 pg. These results highlight the threat posed by ToMMV to tomato and pepper cultivation and offer an efficient detection system for the simultaneous detection of four tobamoviruses and tomato spotted wilt virus infecting tomato plants in the field.  相似文献   

Bentonite-humic acid improves soil organic carbon,microbial biomass,enzyme activities and grain quality in a sandy soil cropped to maize (Zea mays L.) in a semi-arid region          下载免费PDF全文

ZHOU Lei  XU Sheng-tao  Carlos M. MONREAL  Neil B. MCLAUGHLIN  ZHAO Bao-ping  LIU Jing-hui  HAO Guo-cheng 《农业科学学报》2022,21(1):208-221

A bentonite-humic acid (B-HA) mixture added to degraded soils may improve soil physical and hydraulic properties, due to effects such as improved soil structure and increased water and nutrient retention, but its effect on soil physicochemical and biological properties, and grain quality is largely unknown.  The effect of B-HA, added at 30 Mg ha⁻¹, was studied at 1, 3, 5 and 7 years after its addition to a degraded sandy soil in a semi-arid region of China.  The addition of B-HA significantly increased water-filled pore space and soil organic carbon, especially at 3 to 5 years after its soil addition to the soil.  Amending the sandy soil with B-HA also increased the content of microbial biomass (MB)-carbon, -nitrogen and -phosphorus, and the activities of urease, invertase, catalase and alkaline phosphatase.  The significant effect of maize (Zea mays L.) growth stage on soil MB and enzyme activities accounted for 58 and 84% of their total variation, respectively.  In comparison, B-HA accounted for 8% of the total variability for each of the same two variables.  B-HA significantly enhanced soil properties and the uptake of N and P by maize in semi-arid areas.  The use of B-HA product would be an effective management strategy to reclaim degraded sandy soils and foster sustainable agriculture production in northeast China and regions of the world with similar soils and climate.  相似文献   

Effects of suspended solids in the survival and haematological parameters of pacu juveniles (Piaractus mesopotamicus) in a biofloc technology culture system     

Lucas Pellegrin  Lilian Fiori Nitz  Daniel de S Britto Pinto  Carlos Eduardo Copatti  Wilson Wasielesky  Luciano Garcia 《Aquaculture Research》2022,53(1):276-284

This study determined the effects of total suspended solids (TSS) on pacu (Piaractus mesopotamicus) culture in a biofloc technology (BFT) system by performing two experiments. Experiment 1 evaluated the LC50-96 h of pacu at seven TSS levels (0, 1500, 3000, 4000, 5000, 6000 and 7000 mg L^?1). Experiment 2 evaluated haematological variables (glucose, pH, haematocrit, haemoglobin, erythrocytes and haematimetric indices) in juveniles exposed to five different sublethal TSS concentrations (0, 250, 500, 750 and 1000 mg L^?1) for 5 days. Treatments below 5000 mg L^?1 did not cause mortality, and the LC50-96 h of TSS was estimated at 5477 mg L^?1. The TSS concentrations that caused mortality in pacu juveniles were extremely high and rarely maintained in culture systems. Exposure to high TSS concentrations (mainly 750 and 1000 mg L^?1) increased blood glucose, pH, heamatocrit, erythrocytes, haemoglobin values and haematimetric indices on the first day. On the fifth day, most of the evaluated parameters stabilized at different TSS concentrations. In conclusion, pacu exposed to high TSS concentrations for short periods may undergo physiological changes, and TSS concentrations below 250 mg L^?1 are recommended for its culture in a BFT system.  相似文献   

Time lag between peak concentrations of plasma and salivary cortisol following a stressful procedure in dairy cattle     

Carlos E Hernandez  Tomas Thierfelder  Kerstin Svennersten-Sjaunja  Charlotte Berg  Agustin Orihuela  Lena Lidfors 《Acta veterinaria Scandinavica》2014,56(1)

Background

Measurement of salivary cortisol has been used extensively as a non-invasive alternative to blood sampling to assess adrenal activity in ruminants. However, there is evidence suggesting a considerable delay in the transfer of cortisol from plasma into saliva. Previous studies in cattle have used long sampling intervals making it difficult to characterise the relationship between plasma and salivary cortisol (PLCort and SACort, respectively) concentrations at different time points and determine whether or not such a time lag exist in large ruminants. Therefore, the objective of this study was to characterise the relationship between plasma and salivary cortisol and determine if there is a significant time lag between reaching peak cortisol concentrations in plasma and saliva across a 4.25 h time-period, using short sampling intervals of 10–15 min, following social separation in dairy cattle.Five cows were separated from their calves at 4 days after calving, and six calves were separated from a group of four peers at 8 weeks of age. Following separation, the animals were moved to an unfamiliar surrounding where they could not see their calves or pen mates. The animals were catheterised with indwelling jugular catheters 1 day before sampling. Blood and saliva samples were obtained simultaneously before and after separation.

Results

In response to the stressors, PLCort and SACort increased reaching peak concentrations 10 and 20 min after separation, respectively. This suggested a 10 min time lag between peak cortisol concentrations in plasma and saliva, which was further confirmed with a time-series analysis. Considering the 10 min time lag, SACort was strongly correlated with PLCort (P < 0.0001).

Conclusions

Salivary cortisol correlates well with plasma cortisol and is a good indicator of the time-dependent variations in cortisol concentrations in plasma following acute stress. However, there is a time lag to reach peak cortisol concentrations in saliva compared to those in plasma, which should be considered when saliva samples are used as the only measure of hypothalamic-pituitary-adrenal axis response to stress in cattle.  相似文献   

Isolation of Streptococcus suis from 2 lambs with a history of lameness     

Anne Muckle  Alfonso López  Marcelo Gottschalk  Carlos López-Méndez  Jan Giles  Lorraine Lund  Matthew Saab 《The Canadian veterinary journal. La revue veterinaire canadienne》2014,55(10):946-949

Streptococcus suis was isolated postmortem from 2 lambs with a history of lameness. Identity of S. suis was confirmed by species-specific polymerase chain reaction (PCR) and by 16S rRNA gene sequencing. One isolate was untypable by serotyping and non-encapsulated, while the other isolate was serotype 33. The lambs had come from the same farm, and there was no evidence of contact between the lambs and pigs. Although the natural niche for S. suis is considered to be the pig, a wide range of host species may be affected by this pathogen.  相似文献   

Detection of retinoid receptors in non-neoplastic canine lymph nodes and in lymphoma     

Carlos H. de Mello Souza  Victor E.O. Valli  Barbara E. Kitchell 《The Canadian veterinary journal. La revue veterinaire canadienne》2014,55(1):1219-1224

This study evaluated the difference in retinoid receptor expression between non-neoplastic lymph nodes and nodal lymphoma in dogs. Retinoid receptor expression was evaluated by immunohistochemistry in 32 canine lymph nodes. The lymph nodes had been previously diagnosed as non-neoplastic (6 normal and 7 hyperplastic lymph nodes) and B- and T-cell lymphoma (19 cases). Immunohistochemistry for retinoic acid receptors and retinoid-X receptors (and their subtypes α, β, and γ) was performed in all cases. In addition, immunohistochemistry for CD3 and CD79a was performed in all lymphoma cases. Non-neoplastic lymphocytes were negative for all retinoid receptors. Retinoic acid receptor-γ was detected in 100% of B-cell lymphoma and 78% of T-cell lymphoma, while retinoid X receptor-γ was positive in 78% of T-cell lymphoma cases. When normal lymph node architecture was still present, a contrast between retinoid-negative benign cells and retinoid-positive malignant cells was clear. Retinoid receptors were expressed in neoplastic, but not in benign lymphocytes, suggesting their value for both diagnosis and treatment of canine lymphoma.  相似文献