Biological Activities of Ethanolic Extracts from Deep-Sea Antarctic Marine Sponges

We report on the screening of ethanolic extracts from 33 deep-sea Antarctic marine sponges for different biological activities. We monitored hemolysis, inhibition of acetylcholinesterase, cytotoxicity towards normal and transformed cells and growth inhibition of laboratory, commensal and clinically and ecologically relevant bacteria. The most prominent activities were associated with the extracts from sponges belonging to the genus Latrunculia, which show all of these activities. While most of these activities are associated to already known secondary metabolites, the extremely strong acetylcholinesterase inhibitory potential appears to be related to a compound unknown to date. Extracts from Tetilla leptoderma, Bathydorus cf. spinosus, Xestospongia sp., Rossella sp., Rossella cf. racovitzae and Halichondria osculum were hemolytic, with the last two also showing moderate cytotoxic potential. The antibacterial tests showed significantly greater activities of the extracts of these Antarctic sponges towards ecologically relevant bacteria from sea water and from Arctic ice. This indicates their ecological relevance for inhibition of bacterial microfouling.     

Agreement between T2 and haste sequences in the evaluation of thoracolumbar intervertebral disc disease in dogs

The purpose of this study was to compare half-Fourier-acquisition single-shot turbo spin-echo (HASTE) and T2-weighted (T2-W) sequences in dogs with thoracolumbar disc extrusion. MRI studies in 60 dogs (767 individual intervertebral disc spaces) were evaluated. Agreement between T2-W and HASTE sequences was assessed for two criteria: presence of an extradural lesion and treatment recommendation. There was moderate agreement between T2-W and HASTE sequences as to presence of an extradural lesion (kappa = 0.575). HASTE was in agreement in 96.1% of the sites where no extradural lesion was identified on T2-W images, but only in 58.1% of the sites where extradural lesions were identified on T2-W images. There was also moderate agreement between T2-W and HASTE sequences as to treatment recommendations (kappa = 0.476). HASTE was in agreement in 98.4% of the sites where a lesion was considered nonsurgical on T2 but only 82.1% of sites a lesion was considered surgical on T2. In 1.0% of sites considered not surgical and in 9.8% of sites considered equivocal based on T2-W images, a surgical lesion was identified on HASTE. Acquisition of a HASTE sequence in addition to conventional sequences may be beneficial in determining the severity of spinal cord compression in some cases when evaluating the canine spine.     

Seroprevalence of chlamydial infection in cattle in Ireland

Although few studies have investigated the prevalence of chlamydial infections in cattle, reported prevalence rates vary hugely. In order to assess the prevalence of this infection in cattle in Ireland, serum samples (100 herds, 20 samples/herd) collected for statutory screening for brucellosis were examined by soluble chlamydial antigen indirect ELISA. The assay detects antibodies to the two most common Chlamydiaceae spp. affecting cattle, namely Chlamydia abortus and Chlamydia pecorum. A total of 95 samples from 57 herds were seropositive, representing an observed prevalence rate of 4.75%. The parametric bootstrap estimate of the mean disease prevalence in the population was 6.04% (95%, CI 4.70-7.50). The results suggest the prevalence of chlamydial infection is low in cattle in Ireland.     

Pododermatitis in turkeys

Severe pododermatitis is a common lesion in turkeys, unlike in broiler chickens. Both dietary factors (soybean meal, biotin, methionine) and poor litter conditions (wet litter) are documented etiologies of footpad lesions. In the United States and United Kingdom both farm managers and processors monitor lesions. The United Kingdom reports an average footpad relative score higher than that of the United States. In both countries, incidence in toms is higher than in hens. There is no significant difference by country. Data support no consistent association with other lesions (i.e., breast blisters or condemnations), breed, or performance parameters (i.e., weight gain or age). The litter type used in the United Kingdom is either straw or wood shavings, whereas in the United States producers predominantly use wood shavings. In the United Kingdom, diets are formulated with a higher protein, which affects the excreta and subsequent litter conditions. British United Turkey is the predominate breed in the United Kingdom. In the United States, three breeds, British United Turkey of America, hybrid, and Nicholas, are common. Recent research has demonstrated the association between biotin levels and pododermatitis. Factors associated with pododermatitis (such as production systems, wet litter, and stocking density) are discussed. There are some indications that increased stocking density is associated with pododermatitis lesions. Further research is needed to identify what management factors are associated with pododermatitis.     

The role of T cells in protection by an inactivated infectious bursal disease virus vaccine

The current belief is that the humoral immune response plays the principal role in defense against virulent infectious bursal disease virus (IBDV). In this study we used a model, in which chickens were compromised in functional T cells by neonatal thymectomy and Cyclosporin A (TxCsA) treatment, to demonstrate the role of T cells in protective immunity against IBDV. We demonstrated that T cells were necessary to achieve full protection against virulent IBDV. When T cell compromised TxCsA-treated chickens were vaccinated with an inactivated IBDV (iIBDV) vaccine, 91% were not protected against IBDV challenge in comparison to T cell-intact chickens, which had a protection rate of 91%. The iIBDV vaccine induced virus neutralizing (VN) and ELISA antibodies, respectively, in 65 and 5% of TxCsA-treated, and in 100 and 58% of T cell-intact birds. These observations provide evidence that the stimulation of T helper cells is needed for the production of protective antibody levels in iIBDV-vaccinated chickens. Passive administration of VN anti-IBDV antibodies inducing a circulating antibody level of log(2)8 in chickens revealed that the levels of antibodies that protected T cell-intact chickens against virulent IBDV challenge were not protective for TxCsA chickens. These results indicated that antibody alone was not adequate in inducing protection against IBDV in chickens and that T cell-involvement was critical for protection. We propose that the inability of iIBDV to protect TxCsA chickens was due to compromised T cell immunity, functional T helper cells and most likely also cytotoxic T cells are needed in iIBDV vaccine protection.     

Wood characteristics of Podocarpus oleifolius var. macrostachyus (Parl.) Buchholz and Gray native to Costa Rica: their significance for wood utilization

Due to over-exploitation in the past, native conifer species in many tropical countries are hardly available anymore for wood utilization. In the last decades Costa Rica has undertaken considerable efforts to study the silvicultural characteristics of the native species of the family Podocarpaceae, in particular Podocarpus oleifolius var. macrostachyus (Parl.) Buchholz and Gray, in order to evaluate its suitability for cultivation in mixed plantations with preference for native species. However, sufficient information on the structural, chemical and physical characteristics of the wood of this species are not available. This investigation reports on selected wood characteristics of old-growth trees from the Cordillera de Talamanca (approximately 2,700 m a.s.l.), Costa Rica. Tracheids occupy 93% of total volume; average tracheid length is 4 mm, wall thickness ranges 2.5–4.5 (–6.5) μm throughout the annual increment. Lignin content is between 33.6 and 34.7% excluding any lignin-like compounds. Cellular UV microspectrophotometry reveals that the compound middle lamella (CML) and S2 layer are characterized by a higher absorbance than is commonly observed in e.g. Pinaceae, and with a distinct gradient from S1 to S3. The carbohydrate (cellulose and hemicelluloses) composition reflects the typical proportions as found in other conifers. A low content of organic extractives explains the only moderate (white rot) to low (brown rot) natural durability of the heartwood against wood destroying fungi. The wood density (12% mc) ranges 0.5–0.68 g cm^-3; compression strength (44±2.38 MPa) and corresponding modulus of elasticity (8,600±1,720 MPa) indicate good elastomechanical properties. Accordingly, the wood is recommended for multiple indoor enduses. For exterior applications, effective protective measures and/or preservative treatment are required. Dedicated to Prof. Dr. Dr. h.c. mult. Walter Liese on the occasion of his 80th birthday     

IMAGING DIAGNOSIS–SCLEROSING ENCAPSULATING PERITONITIS IN A DOG

An approximately 5‐month‐old American Staffordshire terrier was presented with a history of recurrent peritoneal effusion. Abdominal radiographs and ultrasound showed a loculated effusion in the ventral abdomen with dorsal displacement of abdominal organs, hepatomegaly and rounding of liver and splenic margins. Computed tomography demonstrated centrally located gastrointestinal segments surrounded by a thin soft tissue band and a thickened peritoneal lining. At necropsy a fibrous membrane continuous with liver and splenic capsules encapsulated all abdominal organs. Microscopically the abdominal wall and fibrous capsule consisted of an irregular thick layer of hypocellular connective tissue. The final diagnosis was sclerosing encapsulating peritonitis.     

Bilateral effects of vaccination against infectious bursal disease and Newcastle disease in specific-pathogen-free layers and commercial broiler chickens

Different infectious bursal disease virus (IBDV) live vaccines (intermediate, intermediate plus) were compared for their immunosuppressive abilities in specific-pathogen-free (SPF) layer-type chickens or commercial broilers. The Newcastle disease virus (NDV) vaccination model was applied to determine not only IBDV-induced immunosuppression but also bilateral effects between IBDV and NDV. None of the IBDV vaccines abrogated NDV vaccine-induced protection. All NDV-vaccinated SPF layers and broilers were protected against NDV challenge independent of circulating NDV antibody levels. Sustained suppression of NDV antibody development was observed in SPF layers, which had received the intermediate plus IBDV vaccine. We observed a temporary suppression of NDV antibody development in broilers vaccinated with one of the intermediate, as well as the intermediate plus, IBDV vaccines. Different genetic backgrounds, ages, and residual maternal antibodies might have influenced the pathogenesis of IBDV in the different types of chickens. Temporary suppression of NDV antibody response in broilers was only seen if the NDV vaccine was administered before and not, as it was speculated previously, at the time the peak of IBDV-induced bursa lesions was detected. For the first time, we have demonstrated that the NDV vaccine had an interfering effect with the pathogenesis of the intermediate as well as the intermediate plus IBDV vaccine. NDV vaccination enhanced the incidence of IBDV bursa lesions and IBDV antibody development. This observation indicates that this bilateral effect of an IBDV and NDV vaccination should be considered in the field and could have consequences for the performance of broiler flocks.     

Effect of nitrogen fertilization and irrigation on soil microbial activities and population dynamics — a field study

In a field experiment, net nitrogen (N) mineralization and immobilization were studied in relation to: 1) population dynamics and activities of N-metabolizing soil microbial communities, 2) changes in substrate-induced respiration (SIR) and 3) potential urease acitvity. Nitrogen fertilization (80 kg NO₃-N ha^-1) without irrigation induced additional N mineralization up to 280 kg N ha^-1. Net N-mineralization was weakly correlated to cell numbers of ammonifying and NH₄⁺-oxidizing microorganisms. Potential urease activity, respiration activity, and substrate-induced respiration activity were not correlated with the amount of mineralized nitrogen. Irrigation significantly increased potential urease activity of the soil microflora. Substrate induced respiration activity and basal respiration activity of the soil microflora were highest in the unfertilized and non irrigated treatment. But greatest differences were detected between the two sampling dates. NO₂^--oxidizing and ammonifying microbial populations increased, while populations of NH₄⁺-oxidizing and denitrifying microorganisms decreased with time. The results of this study demonstrate the interaction of nitrogen fertilizer application and irrigation on population dynamics of N-transforming soil microorganisms and microbial activities under field conditions. Detailed microbiological investigations of this type improve our understanding of nitrogen transformations in soil and suggest possible reasons of nitrogen losses, so that N fertilizer can be used more effectively and N losses be reduced.