Long-term effects of N fertilization on cropping and growth of olive trees and on N accumulation in soil profile

Two experiments were conducted for 13 years in two olive groves of southern Spain to study the long-term effect of nitrogen (N) fertilization on trees and soil. In the first experiment, 12-year-old ‘Picual’ olive trees were arranged in a split plot design with method of N application (soil versus a 50% soil:50% foliar combination) as the whole plot factor, and amount of N applied annually (0, 0.12, 0.25, 0.5 or 1.0 kg N tree⁻¹) as the subplot factor. In the second experiment, N application to 50-year-old ‘Picual’ trees was based on the previous season's leaf N concentration. Urea was the source of N in both experiments. During the last 4 years, soil samples were taken at 0–20, 20–40, 40–60, 60–80, and 80–100 cm depth to evaluate the effect of N application on soil eutrophication. Fertilization with N had no significant effects on yield, fruit characteristics, and growth of olive trees for the 13 years of study, even when leaf N concentration increased with the amount of fertilizer N applied. Combining soil and foliar application may reduce the amount of fertilizer N necessary to correct a possible N deficiency because our experiments showed this practice to be more effective in increasing leaf N that applying N only to the soil. Our results question the established deficiency threshold of 1.4% of N in dried leaf because no reduction in yield or growth was observed for lower concentrations. However, leaf N concentration did not drop below 1.2% after 13 years with no N application, probably because of N inputs from rainfall and the mineralization of organic N. Whereas under natural conditions of the non-fertilized treatments NH₄⁺–N represented the dominant fraction of mineral N in soil, accumulation of high amounts of NO₃⁻–N in the soil profile occurred in the fertilized plots, which represents a high risk of N leaching from soil. All these results suggest that annual applications of fertilizer N are unnecessary to maintain high productivity and growth in olive. Applying N only when the previous season's leaf analysis indicates that leaf N concentration is below the deficiency threshold, is thus a recommended practice to optimize N fertilization in olive orchards and to reduce N losses by leaching.     

Evaluation of the isoflurane‐sparing effects of fentanyl,lidocaine, ketamine,dexmedetomidine, or the combination lidocaine‐ketamine‐dexmedetomidine during ovariohysterectomy in dogs

ObjectiveTo evaluate the isoflurane‐sparing effects of an intravenous (IV) constant rate infusion (CRI) of fentanyl, lidocaine, ketamine, dexmedetomidine, or lidocaine‐ketamine‐dexmedetomidine (LKD) in dogs undergoing ovariohysterectomy.Study designRandomized, prospective, blinded, clinical study.AnimalsFifty four dogs.MethodsAnesthesia was induced with propofol and maintained with isoflurane with one of the following IV treatments: butorphanol/saline (butorphanol 0.4 mg kg^?1, saline 0.9% CRI, CONTROL/BUT); fentanyl (5 μg kg^?1, 10 μg kg^?1 hour^?1, FENT); ketamine (1 mg kg^?1, 40 μg kg^?1 minute^?1, KET), lidocaine (2 mg kg^?1, 100 μg kg^?1 minute^?1, LIDO); dexmedetomidine (1 μg kg^?1, 3 μg kg^?1 hour^?1, DEX); or a LKD combination. Positive pressure ventilation maintained eucapnia. An anesthetist unaware of treatment and end‐tidal isoflurane concentration (Fe′Iso) adjusted vaporizer settings to maintain surgical anesthetic depth. Cardiopulmonary variables and Fe′Iso concentrations were monitored. Data were analyzed using anova (p < 0.05).ResultsAt most time points, heart rate (HR) was lower in FENT than in other groups, except for DEX and LKD. Mean arterial blood pressure (MAP) was lower in FENT and CONTROL/BUT than in DEX. Overall mean ± SD Fe′Iso and % reduced isoflurane requirements were 1.01 ± 0.31/41.6% (range, 0.75 ± 0.31/56.6% to 1.12 ± 0.80/35.3%, FENT), 1.37 ± 0.19/20.8% (1.23 ± 0.14/28.9% to 1.51 ± 0.22/12.7%, KET), 1.34 ± 0.19/22.5% (1.24 ± 0.19/28.3% to 1.44 ± 0.21/16.8%, LIDO), 1.30 ± 0.28/24.8% (1.16 ± 0.18/32.9% to 1.43 ± 0.32/17.3%, DEX), 0.95 ± 0.19/54.9% (0.7 ± 0.16/59.5% to 1.12 ± 0.16/35.3%, LKD) and 1.73 ± 0.18/0.0% (1.64 ± 0.21 to 1.82 ± 0.14, CONTROL/BUT) during surgery. FENT and LKD significantly reduced Fe′Iso.Conclusions and clinical relevanceAt the doses administered, FENT and LKD had greater isoflurane‐sparing effect than LIDO, KET or CONTROL/BUT, but not at all times. Low HR during FENT may limit improvement in MAP expected with reduced Fe′Iso.     

Seasonal variations in biochemical composition and condition index of cultured mussels (Mytilus galloprovincialis Lmk) in the Lagoon of Venice (North Adriatic)

Seasonal changes in the main biochemical components and in the condition index of cultured mussels (Mytilus galloprovincialis Lmk) from the Venice Lagoon have been followed during the period October 1979–August 1981.Carbohydrates (2–32%) show winter minima and summer maxima, while proteins (30–52%) have a rather irregular pattern. Lipids (2–13%) and condition index exhibit an annual cycle with two minima (late spring; autumn-winter) and two maxima (early spring; summer).Seasonal variations of biochemical composition and condition index are discussed in connection with the reproductive cycle and some environmental parameters such as temperature and phytoplankton availability.The comparison between the present data and those from other geographic areas confirms the peculiarity of the environment of the Venice Lagoon.     

Dense populations of a giant sulfur bacterium in Namibian shelf sediments

A previously unknown giant sulfur bacterium is abundant in sediments underlying the oxygen minimum zone of the Benguela Current upwelling system. The bacterium has a spherical cell that exceeds by up to 100-fold the biovolume of the largest known prokaryotes. On the basis of 16S ribosomal DNA sequence data, these bacteria are closely related to the marine filamentous sulfur bacteria Thioploca, abundant in the upwelling area off Chile and Peru. Similar to Thioploca, the giant bacteria oxidize sulfide with nitrate that is accumulated to 相似文献   

Comparative studies of PKX and Sphaerospora spp. from salmonids using lectin and monoclonal antibody staining techniques

The results of comparative immunohisto-chemical staining studies with two lectin probes, GS-I and SBA, and five monoclonal antibodies raised against the PKX myxosporean are presented. In order to investigate the postulated link between PKX and Sphaerospora spp., the lectins and monoclonal antibodies were tested against PKX, Sphaerospora renicola, Sphaerospora oncorhynchi, Sphaerospora elegam, Sphaerospora truttae and Sphaero-spora sp. from Atlantic salmon, Salmo salar L., and Ceratomyxa shasta. SBA appears a useful tool for tbe diagnosis of all Sphaerospora spp. infections and was also positive for C. shasta. GS-I and monoclonal antibodies (12, C5, D4 and A3) appear to be specific for both the extrasporogonic and sporogonic stages of PKX. Although MabB4 was raised to PKX, it appears to stain some of the sporogonic stages of Sphaerospora spp. but not C. shasta. The results of the lectin and monoclonal staining of PKX and Sphaerospora oncorhynchi indicated that further work was required to prove or disprove the hypothesis that PKX and S, oncorhynchi are the same organism.     

Toll-like receptor expression in the nervous system of bovine alpha-herpesvirus-infected calves

In this study, the expression levels of viral Toll-like receptors (TLRs) in the nervous system of bovine herpesvirus type 5 (BoHV-5)-infected calves were investigated. A significant increase in the expression of TLRs 3 and 7–9 was found in the anterior cerebral cortex during acute infection and viral reactivation. In the trigeminal ganglia, only TLR9 expression was significantly affected. The magnitude of the increase was lower in BoHV-1-infected calves, suggesting that a restricted immune response might protect against exacerbated inflammatory responses in the brain. This work describes, for the first time, the involvement of TLRs 3 and 7–9 in the recognition of BoHV in the bovine nervous system, indicating that the expression of these receptors might be associated with the development of neurological disease. Modulation of the signalling pathways mediated by TLRs might provide an effective approach to control the neuro-immune response to BoHV-5, which may be responsible for neurological lesions.     

Analysis of the oxidative degradation of proanthocyanidins under basic conditions

Proanthocyanidin isolates from grape (Vitis vinifera L. cv. Pinot noir) skin and seed underwent oxidative degradation in solution (10 g/L) under basic conditions while exposed to atmospheric oxygen. Degradation was monitored by reversed-phase HPLC following acid-catalyzed cleavage in the presence of excess phloroglucinol (phloroglucinolysis) and by high-performance gel permeation chromatography. All isolates degraded under these conditions and followed second-order kinetics for over 1 half-life, consistent with an oxidation reaction. The conversion of proanthocyanidins to known subunits (conversion yield) when measured by phloroglucinolysis showed a dramatic decline over the course of the reaction. With the exception of (+)-catechin extension subunits, all individual subunits decreased in concentration during the oxidation process, also following second-order kinetics for over 1 half-life. Skin proanthocyanidins degraded the fastest due to the presence of (-)-epigallocatechin extension subunits. Seed procyanidins were degraded with and without flavan-3-ol monomers. Flavan-3-ol monomers slowed the rate of seed procyanidin degradation. The mean degree of polymerization (mDP) determined by phloroglucinolysis indicated a large decrease in mDP as the reaction progressed; yet, by GPC, the size distribution of all proanthocyanidins changed little in comparison. The conversion yield could be an important parameter to follow when using phloroglucinolysis as a means for determining proanthocyanidin mDP, and when monitoring the oxidative degradation of proanthocyanidins.     

Influence of the freshness grade of raw fish on the formation of volatile and biogenic amines during the manufacture and storage of vinegar-marinated anchovies

Volatile and biogenic amines from three batches of anchovies, marinated in vinegar, were studied. The anchovies had been vacuum-packed and kept in refrigerated storage for 3 months. Trimethylamine and total volatile basic nitrogen levels were very low and constant throughout marinating and storage process: less than 1 and 10 mg/100 g, respectively. Certain amine levels, mainly those of tyramine and serotonin, increased slightly, particularly during storage. However, even the highest recorded levels were much lower than those considered to be hazardous for human consumption. To study the influence of raw material freshness in the amine profile, two laboratory trials using fresh and spoiled anchovies and simulating the industry standard marinating process were carried out. Levels for both volatile and biogenic amines were dependent on raw material quality, proving consistently higher in those deriving from nonfresh fish. Vinegar marinating leads to a decrease in the accumulation of amines in anchovy while their concentration in the vinegar solution increases due to the vinegar effect as solvent extractor.     

Pathological changes in the lungs and mammary glands of sheep and their relationship with maedi-visna infection.

Maedi-visna, a multisystemic disease of adult sheep, was first described in Spain in 1984. To get an idea of the seroprevalence of the disease locally and to estimate the number of seropositive animals with lesions, samples of blood, lungs and mammary glands were taken from 124 randomly selected sheep killed in the main slaughterhouse of Zaragoza. In the agar gel immunodiffusion test, 74 (59.7 per cent) of the sheep were positive and 50 were negative. Among the 74 seropositive animals, 19 (25.6 per cent) had no lesions in any organ, 12 (16.2 per cent) had lesions in the lungs only, 15 (20.2 per cent) had lesions in the mammary glands and 28 (37.8 per cent) had lesions in both organs. In the lungs hyperplasia of lymphoid follicles was more evident than an interstitial infiltrate but in the mammary glands this relationship was not observed. Even when the lesions occurred in both organs, they did not show the expected proportion in terms of either type or severity. Among the 50 seronegative sheep, eight (16 per cent) showed maedi-like lesions, formed exclusively by the hyperplasia of lymphoid follicles.