Detection of chlorine-labelled chitosan in Scots pine by energy-dispersive X-ray spectroscopy     

Erik Larnøy  Morten Eikenes  Holger Militz 《Wood Science and Technology》2011,45(1):103-110

The aim of this study was to use energy-dispersive X-ray spectroscopy (EDX) to localize chitosan in the cell wall of chitosan-impregnated Scots pine. It was of interest to investigate the concentration of chitosan in wood to gain further knowledge and understanding of the distribution of chitosan in the wooden matrix. After deacetylation, chitosan was re-acetylated with chloroacetic anhydride to achieve a covalent bonding of chloride to the chitosan polymer. Chloride-labelled chitosan was measured by EDX using a scanning electron microscope and described as chloride intensity. Analysis of free chloride anions was performed by dialysis and inductively coupled plasma atomic emission spectroscopy. There was a significant correlation between the molecular weight of chitosan and the intensity of covalent-bonded chloride to the chitosan polymer. High molecular weight chitosan showed a better interaction with the cell wall structure than low molecular chitosan.  相似文献   

Carryover of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) from soil to plant and distribution to the different plant compartments studied in cultures of carrots (Daucus carota ssp. Sativus), potatoes (Solanum tuberosum), and cucumbers (Cucumis Sativus)     

Lechner M  Knapp H 《Journal of agricultural and food chemistry》2011,59(20):11011-11018

A vegetation study was carried out to investigate the carryover of Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonate (PFOS) from soil mixed with contaminated sewage sludge to potato, carrot, and cucumber plants. Analysis was done by liquid-extraction using acetonitrile with dispersive SPE cleanup and subsequent HPLC-MS/MS. In order to assess the transfer potential from soil, transfer factors (TF) were calculated for the different plant compartments: TF = [PFC](plant (wet substance))/[PFC](soil (dry weight)). The highest TF were found for the vegetative plant compartments with average values for PFOS below those for PFOA: cucumber, 0.17 (PFOS), 0.88 (PFOA); potato, 0.36 (PFOS), 0.40 (PFOA); carrot, 0.38 (PFOS), 0.53 (PFOA). Transfer of PFOA and PFOS into potato peelings (average values of TF: PFOA 0.03, PFOS 0.04) exceeded the carryover to the peeled tubers (PFOA 0.01, PFOS < 0.01). In carrots, this difference did not occur (average values of TF: PFOA 0.04, PFOS 0.04). Transfer of PFOS into the unpeeled cucumbers was low and comparable to that of peeled potatoes (TF < 0.01). For PFOA, it was higher (TF: 0.03).  相似文献   

Neuromuscular disorders in the cat: clinical approach to weakness     

Volk HA  Shihab N  Matiasek K 《Journal of Feline Medicine and Surgery》2011,13(11):837-849

PRACTICAL RELEVANCE: Weakness is a relatively common clinical presentation in feline medicine and can be caused by primary neuromuscular disease or by diseases of other body systems affecting the neuromuscular system secondarily. Successful work-up relies on a thorough clinical and neurological examination, and logical problem solving, based on an understanding of the underlying neuroanatomical and pathophysiological mechanisms. CLINICAL CHALLENGES: Feline neuromuscular diseases can be a diagnostic challenge. On initial inspection, the presenting signs can mimic disorders of other body systems, particularly cardiovascular, pulmonary and orthopaedic disease, or may be confused with systemic illnesses. Additionally, because many different pathologies of the feline neuromuscular system converge to a similar clinical phenotype, further diagnostic steps such as electrodiagnostics, cerebrospinal fluid analysis, and muscle and nerve biopsies must be considered even after neuromuscular dysfunction has been identified. AUDIENCE: This review provides a framework for the clinical approach to the weak cat and gives a practical summary of neuromuscular diseases for the general practitioner and specialist alike. EVIDENCE BASE: Many diseases affecting the feline neuromuscular system have been well described in the veterinary literature, mostly based on retrospective case reports and series. The evidence base for the treatment of feline neuromuscular diseases remains very limited.  相似文献   

青藏高寒草甸部分豆科植物根瘤菌的初步研究   总被引：1，自引：0，他引：1  

曾英  刘世贵 《草业科学》1994,11(6):32-34

本文首次对青藏高原川西北高寒草地部分豆科植物进行了根瘤菌共生调查和性质研究，在若尔盖、红原、松潘等地海拔在３０００－３５００ｍ的草地上采集豆科植物根瘤样品５０多份，分别与２４种不同的豆科植物共生结瘤，从中分离到２１株根瘤菌，研究发现，高原高寒盖草地豆科植物种类不如低海拔地区多，根瘤亦不发达，普遍偏小，且无效根瘤较多。由于气温度，根瘤菌对根的感染力不够强，但根瘤菌对低温和紫外线等不利因素有较强的抵抗  相似文献   

Impact of Salmonella Typhimurium DT104 virulence factors invC and sseD on the onset, clinical course, colonization patterns and immune response of porcine salmonellosis     

Brumme S  Arnold T  Sigmarsson H  Lehmann J  Scholz HC  Hardt WD  Hensel A  Truyen U  Roesler U 《Veterinary microbiology》2007,124(3-4):274-285

The present study was conducted to study the impact of the virulence factors invC and sseD of the two type III secretion systems of Salmonella enterica serovar Typhimurium (S. Typhimurium) on the pathogenesis of the porcine S. Typhimurium DT104 infection. For this purpose, two S. Typhimurium mutant strains with a disrupted invC gene of the Salmonella pathogenicity island 1 or with a disrupted sseD gene of the Salmonella pathogenicity island 2 have been studied in experimental infection of pigs. Twenty-two 7-week-old male hybrid pigs were either infected with one of the mutants or the wild-type S. Typhimurium DT104 strain. Each group was examined for clinical signs, Salmonella shedding rate and the specific antibody response. Survival and replication were evaluated by qualitative and quantitative determination of the colonization rate. The humoral and cellular immune responses were examined using isotype-specific ELISA and quantitative real-time PCR of IL-2, IL-4, IL-10, IL-12 and IFN-gamma. The results proved that both mutants had a lower virulence (with marked differences between both mutants) than the wild-type and that both virulence factors have importance in porcine salmonellosis. Only pigs infected with the wild-type S. Typhimurium DT104 exhibited typical clinical symptoms of salmonellosis like anorexia, vomiting, disturbed demeanour, fever and diarrhoea. Deletion of the invC gene resulted in a significantly reduced colonization rate. Interestingly, the mRNA expression of both type-1 and type-2 cytokines were significantly decreased in pigs infected with either the invC-mutant and the sseD-mutant strain.  相似文献   

PREVALENCE AND CHARACTERIZATION OF SMALL TYMPANIC BONE SPICULES AND DRUMSTICK‐LIKE HYPEROSTOTIC TYMPANIC BONE SPICULES IN THE MIDDLE EAR CAVITY OF DOGS          下载免费PDF全文

Birgit Parzefall  Alexandra Rieger  Holger A. Volk  Johann Maierl  Andreas Brühschwein  Andreas Blutke 《Veterinary radiology & ultrasound》2015,56(1):25-32

Rounded, sessile, hyperattenuating structures detected in computed tomography (CT) studies of canine tympanic bullae have been termed “otoliths.” These have been proposed to represent dystrophic mineralizations or heterotopic bone formations in the middle ear that are potentially related to chronic otitis media. Aims of the current study were to describe the prevalence, macroscopic, and histological features of structures consistent with “otoliths” in the canine tympanic cavity. Tympanic bullae from 50 routinely necropsied dogs and 139 retrospectively retrieved CT scans of canine clinical cases were examined. Small tympanic bone spicules with pointed or clubbed tips essentially arising from the free margin of the septum bullae were bilaterally present in the tympanic cavities of all 50 of the necropsied dogs. In 48% of the dogs, “otolith”‐like CT‐detectable bone spicules carrying drumstick‐like hyperostoses that were 1–6 mm in diameter were also present. In the retrospective survey of bulla CT scans of 139 cases, the prevalence of hyperostotic tympanic bone spicules (HTBS) was 20%. Findings from the current study indicated that the presence of small tympanic bone spicules in adult dogs is most likely due to physiological bone growth in the septum bullae and that HTBS represent osseous proliferations of small tympanic bone spicules. However, the factors inducing formation of hyperostotic spicules from small tympanic bone spicules remain unknown. The high prevalence of HTBS displaying a similar appearance in bulla CT scans in dogs suggests that these spicules should be included in a differential diagnosis list for “otoliths.”  相似文献   

Stickstoffflüsse in einem typischen Agrarökosystem Schleswig-Holsteins. Meßergebnisse,Bilanzen, Modellvalidierung     

Claus-G. Schimming  Ralf Mette  Ernst-W. Reiche  Joachim Schrautzer  Holger Wetzel 《植物养料与土壤学杂志》1995,158(4):313-322

  相似文献   

Nitrogen fertilization of strawberries: Nmin,leaf dry matter,and leaf sap analyses as control methods     

Holger Daugaard  Torkild T. Todsen 《Journal of plant nutrition》2013,36(11):1679-1685

In a three‐year survey several control methods of nitrogen (N) supply in strawberry were investigated. It was found that N_min analysis could be used as a measurement of control from the beginning of the season, indicating the need of additional N supply. Leaf dry matter analysis, taken during flowering, could be used as an indicator thus making it possible to make corrections within the season, if needed. When leaf dry matter analysis was compared to leaf sap analysis, correlations were evident for the majority of nutrients, N being an important exception. It was concluded that the use of N_min‐ and leaf dry matter analyses combined might make corrections in N fertilization within the same year possible.  相似文献   

Correction to: The measure mix matters: multiple-component plant protection is indispensable for coping with the enormous genome plasticity and mutation rates in pathogenic microorganisms     

Oliveira-Garcia  Ely  von Tiedemann  Andreas  Deising  Holger B. 《植物病害和植物保护杂志》2021,128(1):7-7

Journal of Plant Diseases and Protection - In the original publication of the article, the first author name is incorrectly published.  相似文献   

Crown plasticity reduces inter-tree competition in a mixed broadleaved forest   总被引：1，自引：0，他引：1  

Fleur Longuetaud  Alexandre Piboule  Holger Wernsdörfer  Catherine Collet 《European Journal of Forest Research》2013,132(4):621-634

The objective of the study was to analyse to which extent horizontal crown plasticity reduces inter-tree competition at stand scale, and how it relates to species growth strategy. Two components of crown plasticity defined at the individual tree level (crown shape distortion, CSD and crown displacement relative to stem, CRD) were analysed and their relative importance in the reduction of competition was quantified. Inter-tree competition at stand scale was estimated using spatial pattern analysis and crown overlap estimation. Measurements were performed in a mixed broadleaved stand of Western Europe. Crown plasticity was shown to regularise the spatial distribution of crowns in comparison with the corresponding stems and to reduce inter-tree competition by optimising space occupation. A significant reduction in crown overlap was observed, mainly due to CRD and secondarily to CSD. At the species level, CSD and CRD were positively correlated. In addition, both were negatively correlated with species shade-tolerance scores. In particular, three European temperate tree species showed contrasting responses, which were related to their known specific ecological strategies. Fagus sylvatica, known to be a highly shade-tolerant species, showed large crowns, low CSD and CRD, indicating a low plasticity and suggesting a strong competitive ability. At the opposite, Quercus sp., known to be clearly less shade-tolerant, exhibited a reduced growth, associated with high CSD and CRD, indicating high crown plasticity and probably a lower competitive ability. For this species, plasticity could be described as passive. Last, Carpinus betulus, known to have a relatively good shade-tolerance, showed a contrasting behaviour with high CSD and CRD and a strong presence in the stand, suggesting high crown plasticity and a good competitive ability. In that case, plasticity was described as rather adaptive.  相似文献