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Interaction between clay microstructure, decomposition of plant residues and humification 总被引:1,自引:0,他引:1
L. P. D'ACQUI E. DANIELE F. FORNASIER L. RADAELLI G. G. RISTORI 《European Journal of Soil Science》1998,49(4):579-587
We have studied microstructural changes in montmorillonite and kaolinite, which were amended with organic debris (leaves of chestnut or beech), microbial inoculum and nutrients and subjected, for 30 days at 25°C, to alternate drying and wetting (D–W) or kept continuously moist at water-holding capacity (WHC). The objective was to evalute the interactions between the decomposition of plant residues and clay microstructural organization in different pore–water regimes. The microstructure was studied by Hg porosimetry, N adsorption at 77 K, and scanning electron microscopy. Decomposition was assessed by measuring residual C and N, the amount of humified material, the relative contents of humic (HA) and fulvic (FA) acids, and their molecular weight distribution. The structural organization at the end of the experiments was different for the two clays, and new classes of pores were found as the result of the microbial metabolism. The decomposition was also significantly affected by clay type. Decomposition of the organic matter (OM) was rapid in the montmorillonite. The humified material occured mainly as low molecular weight FAs. By contrast, transformation was slow in kaolinite, leaving much residual C, and more of the humified material consisted of HAs. Alternate D–W had little effect on microstructure and decomposition. Samples that were kept moist and amended with chestnut leaves produced the greatest amount of humified substances. The dynamics of the decomposition was significantly affected by the nature of the leaves as indicated by the differences in residual C, humified material and C/N ratio. By contrast, changes in pore size distribution (PSD) were litle influenced by the type of organic debris. 相似文献
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GIORGIO BAVESTRELLO CARLO CERRANO DANIELE ZANZI RICCARDO CATTANEO-VIETTI 《水产资源保护:海洋与淡水生态系统》1997,7(3):253-262
1. The analysis, by means of line transects, of a Paramuricea clavata (Anthozoa: Gorgonacea) population forming a facies of the Mediterranean coralligenous community along the Portofino Promontory (Ligurian Sea, Italy) evidenced a high per cent of lesions inflicted to the gorgonian coenenchyme by anchoring and fishing activities. 2. This damage favours the development of aggregates of epibionts (mainly hydroids and bryozoans) which leads to greater mechanical stress through increased resistance of the colonies to water movement; where polychaetes and nematodes colonize the denuded skeleton, their burrowing activity weakens the colony. 3. In situ tissue regeneration experiments suggested that aggregation of epibionts can develop only if the injuries result, from continuing abrasion. 4. Injuries caused by anchoring and fishing can therefore be considered the major cause of mortality of Paramuricea clavata in the Portofino Promontory. 5. Paramuricea clavata re-colonizes experimentally denuded areas slowly and colonies take many years to reach the size of existing individuals and can be damaged easily by fishing and anchoring. 6. Special protection is needed for this key species of Mediterranean coral at Portofino Promontory, which is proposed as a Natural Marine Park. © 1997 John Wiley & Sons, Ltd. 相似文献
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Negligible amounts of carrot (Daucus carota L.) seed were produced in Brazil prior to the release of cv. Brasilia in 1982. This cultivar is tolerant of high temperature and resistant to leaf blight caused by Alternaria dauci (Kühn) Groves & Skolko (Vieira et al ., 1983). Since 1982 technology for production of Brasilia seed has developed rapidly and over 40 t of seed have been produced, representing more than 8000 ha planted. Fungicides are widely used on carrot root crops and growers have naturally extended their use to carrot seed crops. Mancozeb, thiabendazole, captafol and chlorothalonil, applied at weekly intervals, are the most common fungicides used although their efficacy in this new situation has not been evaluated.
A survey of pathogens associated with carrot seed production (Reifschneider & Della Vecchia. 1983) has shown that the most common fungal pathogen is Alternaria radicina Meier, Dreschler & Eddy, a species which is a common seed-borne pathogen in the USA (Rader, 1952) and has been present in Brazil since 1970 or earlier (Luz, 1970).
Since information concerning the control of A. radicina in carrot seed crops is lacking we established a preliminary fungicide experiment in July 1982 within a 5-ha commercial field planted with artificially vernalized roots of which 90% were infected, to varying degrees, with A. radicina . Plots were 25 m2 and each treatment (Table 1) was replicated five times, in a completely randomized design. Seeds were harvested manually at maturity and dried by forced air at c. 30°C. Infection by A. radicina was detected using the method of Soteros (1979) in which heat-treated seeds (100°C for 1 h) are plated on malt agar. A total of 200 seeds per plot (20 seeds per plate) were used. Identification of A. radicina was based on conidium and conidiophore morphology (Ellis & Holliday, 1972). 相似文献
A survey of pathogens associated with carrot seed production (Reifschneider & Della Vecchia. 1983) has shown that the most common fungal pathogen is Alternaria radicina Meier, Dreschler & Eddy, a species which is a common seed-borne pathogen in the USA (Rader, 1952) and has been present in Brazil since 1970 or earlier (Luz, 1970).
Since information concerning the control of A. radicina in carrot seed crops is lacking we established a preliminary fungicide experiment in July 1982 within a 5-ha commercial field planted with artificially vernalized roots of which 90% were infected, to varying degrees, with A. radicina . Plots were 25 m2 and each treatment (Table 1) was replicated five times, in a completely randomized design. Seeds were harvested manually at maturity and dried by forced air at c. 30°C. Infection by A. radicina was detected using the method of Soteros (1979) in which heat-treated seeds (100°C for 1 h) are plated on malt agar. A total of 200 seeds per plot (20 seeds per plate) were used. Identification of A. radicina was based on conidium and conidiophore morphology (Ellis & Holliday, 1972). 相似文献
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G. VIRKEL M. CARLETTI M. CANTIELLO L. DELLA DONNA G. GARDINI F. GIROLAMI C. NEBBIA 《Journal of veterinary pharmacology and therapeutics》2010,33(3):295-303
Virkel, G., Carletti, M., Cantiello, M., Della Donna, L., Gardini, G., Girolami, F., Nebbia, C. Characterization of xenobiotic metabolizing enzymes in bovine small intestinal mucosa. J. vet. Pharmacol. Therap. 33 , 295–303. The intestinal mucosa plays a capital role in dictating the bioavailability of a large array of orally ingested drugs and toxicants. The activity and the expression of several xenobiotic metabolizing enzymes were measured in subcellular fractions from the duodenal mucosa of male veal calves and beef cattle displaying a functional rumen but differing in both age (about 8 months vs. 18 to 24 months) and dietary regimens (i.e., milk replacer plus hay and straw vs. corn and concentrated meal). Intestinal microsomes showed cytochrome P450 (CYP) 2B, 2C‐ and 3A‐mediated activities and the presence of the corresponding immunorelated proteins, but no proof of CYP1A expression and/or functions could be provided. Intestinal microsomes were also active in performing reactions typically mediated by carboxylesterases (indophenylacetate hydrolysis), flavin‐containing monooxygenases (methimazole S‐oxidation), and uridindiphosphoglucuronyltransferases (1‐naphthol glucuronidation), respectively. Cytosolic fractions displayed the glutathione S‐transferase (GST)‐dependent conjugation of 1‐chloro‐2,4‐dinitrobenzene; besides, the GST‐mediated conjugation of ethacrinic acid (GSTπ) or cumene hydroperoxide (GSTα) was matched by the presence of the corresponding immunorelated proteins. Conversely, despite the lack of measurable activity with 3,4‐dichloronitrobenzene, a protein cross reacting with anti‐rat GSTμ antibodies could be clearly detected. Although, as detected by densitometry, CYPs and GST isoenzymes tended to be more expressed in beef cattle than in veal calf preparations, there was a general poor correlation with the rate of the in vitro metabolism of the selected diagnostic probes. 相似文献
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Simone MINATO Giunio B. CHERUBINI Daniele DELLA SANTA Stefano SALVADORI Massimo BARONI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(2):267
The incidence of brain herniation (BH) in association with intracranial meningioma (ICM) in dogs and cats is poorly described. The aim of this study was to evaluate the rate and type of brain herniations in client-owned dogs and cats with ICMs and to determine the meningioma volume (MV) relative to cranial cavity volume (CCV). A retrospective magnetic resonance imaging (MRI) analysis study of 24 cats and 45 dogs with ICMs was conducted to ascertain the presence and characteristics of BH. MV and CCV were measured and their ratio was calculated for each animal. Correlations of MV/CCV with independent variables were analyzed. BH was encountered in 24/24 cats (100%) and 30/45 dogs (66.7%) with ICMs. In cats, the most frequent presentation was foramenal herniation (FMH; 23/24, 95.8%), followed by caudotentorial (CTH; 21/24, 87.5%) and subfalcine (SH; 18/24, 75.0%) herniation. In dogs, the most frequent presentation was SH (28/45; 62.2%), followed by CTH (9/45; 20%) and FMH (2/45; 4.4%). Relative to dogs, cats with ICM had greater incidences of FMH (P<0.001) and CTH (P<0.001). Mean MV/CCV ratio was higher in cats (0.098) than in dogs (0.038; P<0.001). The most common clinical sign of ICM was altered behavior in cats (43%, P<0.01) and seizures in dogs (74.4%, P<0.001). In conclusion, cats were found to be more likely than dogs to present FMH and CTH, with a proportionally greater neoplasia volume. 相似文献
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ELOISA TERZO MARCO DI MARCELLO HESTER McALLISTER BRENDAN GLAZIER DANIELE LO COCO CHIARA LOCATELLI VALENTINA PALERMO PAOLA GIUSEPPINA BRAMBILLA 《Veterinary radiology & ultrasound》2009,50(4):416-422
In this work we investigated which mitral valve leaflet was most often involved in mitral valve prolapse with degenerative mitral valve disease and whether there was an association with breed, age, gender, or weight. Five hundred and thirty-seven dogs with mitral valve prolapse-degenerative mitral valve disease were assessed; the cross-breed dog was the most represented breed (248 dogs, 46.2%). Mitral valve prolapse was more common in male dogs, and the average age was 11.3±2.8 years. Prolapse of the anterior leaflet was present in 48.4% of dogs, prolapse of the the posterior leaflet in 7.1%, and bileaflet prolapse was present in 44.5%; this distribution is different than that typically found in humans. There was a significant correlation between severity of mitral regurgitation and severity of mitral valve prolapse or ISACHC class, and between severity of mitral valve prolapse and ISACHC class. There was no relationship between the particular affected leaflet(s) and severity of mitral regurgitation, severity of mitral valve prolapse, or ISACHC class. Our findings suggest that the susceptibility to the mitral valve prolapse-degenerative mitral valve disease is not confined to a specific breeds and that the specific leaflet prolapsing is different in dogs compared with humans. 相似文献
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Paulo C sar DE FACCIO CARVALHO Jean V ctor SAVIAN Tomas DELLA CHIESA William DE SOUZA FILHO Jos Alfredo TERRA Priscila PINTO Amanda POSSELT MARTINS Sebastian VILLARINO J lio Kuhn DA TRINDADE Pedro Arthur DE ALBUQUERQUE NUNES Gervasio PI EIRO 《农业科学与工程前沿(英文版)》2021,8(1):97-110
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PK DELLA TORRE S. ZAKI M. GOVENDIR DB CHURCH R. MALIK 《Australian veterinary journal》1999,77(5):298-300
OBJECTIVE: To examine the effect of acute haemorrhage on the QRS amplitude of the canine lead II surface electrocardiograph (ECG). DESIGN: Ten adult racing Greyhounds were tranquilised, anaesthetised, positioned in right lateral recumbency and connected to recording electrodes of an ECG unit. Baseline six-lead ECG traces were recorded, and further traces were obtained after one unit (460 mL) of blood, and then a second unit, were collected from the femoral artery. RESULTS: There was a consistent and progressive reduction in amplitude of the QRS complex in all leads during acute haemorrhage. QRS amplitude in lead II after removal of two units of blood averaged 74% of the baseline voltage, with individual values of 61 to 91% (P < 0.0001). There were even greater reductions in QRS amplitudes in lead aVL during haemorrhage. In three additional dogs, reductions in QRS voltages were shown to be accompanied by reductions in end-diastolic left ventricular internal dimensions measured echocardiographically. Furthermore, the effects of haemorrhage on the QRS amplitude and echocardiographic measurements were reversed when circulating blood volume was restored by re-infusion of blood removed previously. CONCLUSION: Acute haemorrhage corresponding to an approximately one-third reduction in blood volume caused a substantial reduction in QRS voltage of the surface ECG. It is postulated that this resulted from diminished ventricular distension as a consequence of reduced venous return. A similar mechanism may account for the small-amplitude ECG complexes associated with pericardial effusion, severe dehydration and hypovolaemia. 相似文献
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DANIELE DELLA SANTA ARIANE SCHWEIGHAUSER FRANCK FORTERRE JOHANN LANG 《Veterinary radiology & ultrasound》2007,48(5):448-450
A 13-month-old, neutered female domestic shorthaired cat was evaluated for vomiting, anorexia, and lethargy. The cat was icteric and hyperbilirubinemic. Radiographically a partially radiolucent proximal duodenal foreign body was suspected. Ultrasonographically, there was a foreign body at the level of the duodenal papilla and dilation of the common bile duct and cystic duct; a diagnosis of extrahepatic biliary tract obstruction secondary to a duodenal foreign body was made. Sonographic findings were confirmed at surgery and a duodenal foreign body was removed. This information defines duodenal foreign body as a cause of extrahepatic biliary obstruction in cats. 相似文献
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