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21.
The global dairy industry, the predominant pathogens causing mastitis, our understanding of mastitis pathogens and the host response to intramammary infection are changing rapidly. This paper aims to discuss changes in each of these aspects. Globalisation, energy demands, human population growth and climate change all affect the dairy industry. In many western countries, control programs for contagious mastitis have been in place for decades, resulting in a decrease in occurrence of Streptococcus agalactiae and Staphylococcus aureus mastitis and an increase in the relative impact of Streptococcus uberis and Escherichia coli mastitis. In some countries, Klebsiella spp. or Streptococcus dysgalactiae are appearing as important causes of mastitis. Differences between countries in legislation, veterinary and laboratory services and farmers' management practices affect the distribution and impact of mastitis pathogens. For pathogens that have traditionally been categorised as contagious, strain adaptation to human and bovine hosts has been recognised. For pathogens that are often categorised as environmental, strains causing transient and chronic infections are distinguished. The genetic basis underlying host adaptation and mechanisms of infection is being unravelled. Genomic information on pathogens and their hosts and improved knowledge of the host's innate and acquired immune responses to intramammary infections provide opportunities to expand our understanding of bovine mastitis. These developments will undoubtedly contribute to novel approaches to mastitis diagnostics and control. 相似文献
22.
CEDAR M. CHITTENDEN BJØRN ÅDLANDSVIK OLE‐PETTER PEDERSEN DAVID RIGHTON AUDUN H. RIKARDSEN 《Fisheries Oceanography》2013,22(1):1-13
The use of pop‐up archival satellite tags (PSATs) to geolocate marine fishes in polar regions is challenging due to the brevity of periods during which there is a defined sunrise and sunset. Models using other environmental parameters are thus required to supplement geolocation data in the estimation of marine migratory routes. The objective of this work was to create a simple method that would estimate the migratory pathways of Atlantic salmon (Salmo salar) in polar regions using temperature and depth recordings. Validated geolocations from PSATs were used to test and constrict the model. The model’s predicted migratory routes were within 100 km of the light‐based geolocations calculated by the tags. By constraining the trajectories through the geolocations, bias was reduced. Sensitivity analyses demonstrated that slight alterations of the location and timing of the start and end points did not affect the mean migratory route estimates. This method is a management tool that can determine the primary habitat areas for any surface‐ or bottom‐dwelling marine species – especially in polar regions, where other methods may be impossible. 相似文献
23.
RNAseq analysis reveals the role of secondary metabolism in the response of URS 21, a race‐nonspecific resistant cultivar,to crown rust
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24.
Paulo André Vidal Bandeira José Morais Pereira Filho Aderbal Marcos de Azevêdo Silva Marcílio Fontes Cezar Olaf Andreas Bakke Uilma Laurentino Silva Jucileide Barbosa Borburema Leilson Rocha Bezerra 《Tropical animal health and production》2017,49(5):1001-1007
This study evaluated the performance and carcass characteristics of lambs fed diets with increasing levels of Mimosa tenuiflora (Willd.) hay replacing Buffel grass (Cenchrus ciliaris). Twenty-eight Santa Inês male lambs with an average body weight (BW) of 20.3 ± 1.49 kg(mean ± SD) were allocated in individual stalls and distributed in a completely random design with four treatments (0, 20, 40, and 60 g/100 g total DM M. tenuiflora hay replacing Buffel grass hay in diet) with seven replications. M. tenuiflora hay at the level of 20% dry matter (DM) total replacing Buffel grass hay increased final weight (P = 0.006), total weight gain (P < 0.001), average daily weight gain (ADWG; P < 0.001), DM intake (P < 0.001), and feed efficiency (P < 0.001). Intake of crude protein, NDFap, ADFap, ash, ether extract, total and non-fibrous carbohydrates, and total digestible nutrients presented a positive quadratic effect with M. tenuiflora hay replacing Buffel grass hay and 40 g/100 g total DM level presented greater intake. There were positive quadratic effects by M. tenuiflora hay inclusion at 20 g/100 g total DM level on slaughtering weight (P = 0.005), hot carcass weight (P = 0.002), cold carcass weight (P = 0.002), empty body weight (P = 0.001), hot carcass yield (P = 0.002), cold carcass yield (P = 0.003), and increase linear on biological yield (P = 0.003). There was no influence on cooling weight loss (P = 0.284). M. tenuiflora hay may be included in lamb diets at amounts up to 20 g/100 g total DM substitution of Buffel grass hay because increase in the nutrients intake, growth performance, and carcass characteristics. 相似文献
25.
Tiago Natal-da-Luz Serena Tidona Bruno Jesus Paula V. Morais José P. Sousa 《Journal of Soils and Sediments》2009,9(3):246-260
Background, aim, and scope Sewage sludge use in agriculture should be limited by the presence of metals and other persistent environmental pollutants.
The present study aims to contribute for the definition of a test battery of ecotoxicological assays that allows a proper
ecotoxicological characterization of sludges, providing information on their potential hazard and identified “safe” application
levels.
Materials and methods Three sludges from distinct sources (urban, olive-processing, and electroplating industries) were tested using avoidance and
reproduction tests with earthworms (Eisenia andrei) and springtails (Folsomia candida) and plant growth tests with turnips (Brassica rapa) and oats (Avena sativa). Different soil–sludge mixture concentrations mimicking recommended/realistic field dosages were tested.
Results Only the sludge from the electroplating industry induced an avoidance response from the earthworms (EC50 = 0.4 t/ha) and collembolans (no observed effect concentration (NOEC) = 15 t/ha). This sludge was the only sludge responsible
for any effect on the reproductive output of the earthworms (EC50 = 7.74 t/ha). Regarding collembolans, none of the sludges tested caused any significant decrease in reproduction. In higher
plant tests, the two industrial sludges were toxic, causing a decrease growth in both species. The EC20 values determined for B. rapa were 20.3 and 24.2 t/ha and for A. sativa 14.7 and 16.2 t/ha for sludges from olive-processing and electroplating industries, respectively.
Discussion The metal loadings of the different test sludges could partially explain the results obtained. The toxicity of the test sludge
from electroplating industry observed on the tested invertebrates and plants could be explained by the high amount of total
chromium from which 22.3% was in the most toxic oxidation state—Cr(VI). However, the toxicity caused by the sludge from the
olive-processing industry in the test plants could be attributed to the presence of other compounds (not measured in this
study) since the metal content was not high enough to induce such an effect. The absence of toxicity showed by the urban test
sludge was in agreement with its low levels of metals.
Conclusions The response of the different test organisms and end points varied according to the sludge type. The urban sludge was non-toxic
whereas the sludge from the electroplating industry caused a toxic effect on almost all parameters measured (avoidance behavior
of both test organisms, reproduction of earthworms, and growth of both plant species). Sludge from the olive-processing industry
only caused a toxic effect on growth of both plant species. By analyzing the sensitivity of the different parameters for the
most toxic sludge, it was found that avoidance and reproduction were more sensitive than plant growth, whereas plant seed
germination was not sensitive at all.
Recommendations and perspectives The ecotoxicological evaluation of wastes can be used as an environmental safety control of sludge use in agriculture. A tiered
approach could be adopted for this purpose, incorporating avoidance tests in the first tier (screening level) and reproduction
and plant growth tests in a second tier. But more evidence aiming to define the most suitable ecotoxicological test battery
for specific sludges with a different contamination profile is still needed. 相似文献
26.
27.
Nitrogen (N) deficiency is one of the most yield-limiting nutrients in upland rice growing regions word wide. A greenhouse experiment was conducted with the objective to evaluate nineteen upland rice (Oryza sativa. L.) genotypes for N use efficiency. The soil used in the experiment was an Oxisol and two N levels used were without N application (low level) and an application of 400 mg N kg?1 of soil (high level). Grain yield and yield components and N uptake parameters were significantly affected by N and genotype treatments. Regression analysis showed that plant height, shoot dry weight, number of panicles per pot, number of grains per panicle, grain harvest index, N uptake in shoot and grain were having significant positive relation with grain yield. Nitrogen concentration of 6.4 g kg?1 in the shoot is established as deficient level and 9.5 g kg?1 as sufficient level at harvest. Agronomic efficiency of N (grain yield/unit of N applied) and N utilization efficiency (physiological efficiency X apparent recovery efficiency) were significantly different among genotypes. These two N use efficiencies were having significant quadratic relationship with grain yield. Soil pH, exchangeable soil Ca and base saturation were having significantly positive association with grain yield. However, soil extractable phosphorus (P), potassium (K), hydrogen (H+), aluminum (Al) and cation exchange capacity were having significantly negative association with grain yield. 相似文献
28.
N. K. Fageria O. P. de Morais A. B. dos Santos M. J. Vasconcelos 《Journal of plant nutrition》2014,37(5):633-642
Phosphorus (P) deficiency is one of the most yield limiting factors for crop production in South American soils. Upland rice (Oryza sativa L.) is an important crop in South American cropping systems, including Brazil. A field experiment was conducted with the objective to evaluate 20 upland rice genotypes for phosphorus (P) use efficiency. The P rate used was low (0 kg P ha?1) and high [87 kg P ha?1 or 200 kg phosphorus pentoxide (P2O5) ha?1]. Plant height, shoot dry weight, grain yield, panicle number, 1000 grain weight, spikelet sterility, and grain harvest index were significantly influenced by P and genotype treatments. The P X genotype interaction was significant for grain yield, indicating that genotypes responded differently under two P rates. Overall, grain yield increased by 12% with the addition of P fertilization. Based on grain yield efficiency index, genotypes were classified into efficient, moderately efficient, and inefficient group. The genotypes that were classified as efficient in P use were BRA032048, BRA042094, BRA02601, BRA032051, BRA032033, BRA052015, BRA042156, BRA01600, BRA01506, BRA052023 and BRA042160. The inefficient genotypes in P us efficiency were BRS Primavera, BRA052045, BRA01596, and BRS Sertaneja. Grain harvest index had a significant positive association with grain yield and spikelet sterility had a significant negative association with grain yield, as expected. Average, P-use efficiency of five genotypes was about 17 kg kg?1 (kg grain yield per kg P applied). 相似文献
29.
30.
Janaína Morone Graciliana Lopes Joo Morais Jorge Neves Vítor Vasconcelos Rosrio Martins 《Marine drugs》2022,20(12)
Nature-based and sustainably sourced cosmetics have been dominating the area of skincare products worldwide. Due to their antioxidant and antiaging properties, compounds from cyanobacteria, such as carotenoids and phycobiliproteins, may replace synthetic ingredients in cosmetic formulations and may be used in products such as sunscreens, skincare creams, and makeup. In this study, we evaluated the potential of acetonic and aqueous extracts from cyanobacteria strains of the genera Cyanobium and Leptothoe and from strains within Synechococcales and Oscillatoriales orders, for use in cosmetics. Extractions were sequentially performed with acetone and water. Extracts were firstly analyzed for their toxicity to keratinocytes, fibroblasts, and endothelial cells (HaCAT, 3T3L1 and hCMEC/D3, respectively). The non-cytotoxic extracts were characterized in terms of total proteins, carotenoids, chlorophyll, phenols, phycobiliproteins, and analyzed for their antioxidant potential against the superoxide anion radical (O2•−), and for their ability to inhibit key enzymes associated with the skin aging process. Aqueous extracts were richer in total proteins and phycobiliproteins. The aqueous extracts of Synechococcales cyanobacterium LEGE 181157 and Synechococcales cyanobacterium LEGE 181150 showed the highest value for total proteins (760.81 and 695.25 μg BSA mL−1dry extract, respectively) and the best values regarding O2•− scavenging (IC50 = 63.24 and 112.18 μg mL−1dry extract, respectively) with a significant negative correlation observed (p < 0.01). Moreover, aqueous extracts of Synechococcales cyanobacterium LEGE 181150 and Synechococcales cyanobacterium LEGE 181157 inhibited hyaluronidase, (IC50 of 483.86 and 645.06 μg mL−1dry extract, respectively), with a significant negative correlation with total proteins (p < 0.05), pointing out the contribution of these compounds to the biological activities observed. Acetonic extracts were richer in carotenoids and phenols. Zeaxanthin and β-carotene were predominant among all strains, being present in higher amount in Cyanobium sp. LEGE 07175 (53.08 μg mg−1) and Leptothoe sp. LEGE 181156 (47.89 μg mg−1), respectively. The same strains also showed the highest values for collagenase inhibition at 750 μg mL−1dry extract (32.88 and 36.61%, respectively). Furthermore, Leptothoe sp. LEGE 181156 exhibited the lowest IC50 value for tyrosinase inhibition (465.92 μg mL−1dry extract) and Synechococcales cyanobacterium LEGE 181157 presented the best values for elastase inhibition (IC50 of 380.50 and IC25 of 51.43 μg mL−1dry extract). In general, cyanobacteria extracts demonstrated potential for being used for antiaging purposes, with aqueous extracts being more efficient at free radicals scavenging and acetonic ones at avoiding degradation of dermal matrix components. 相似文献