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Harvesting of plantation conifers on peatlands is carried out as part of restoration and forestry operations. In particular, in the UK and Ireland, conifer plantations on drained ombrotrophic blanket and raised bogs are increasingly being removed (by harvesting), along with blocking of drainage ditches to help raise water tables to reinitiate and restore bog vegetation and function. However, both tree harvesting and peatland restoration operations can have significant impacts on water quality at local and catchment scales. Previous research has suggested that leaching from leftover decomposing brash (tree tops and branches, including wood and needles) is the primary cause, while other work has suggested that release from rewetted peat also contributes to water quality changes. This research investigates the relative importance of peat rewetting, needles and branches on water quality using mesocosm experiments, to help elucidate the mechanisms behind water quality changes following restoration and harvesting operations. Peat and brash were collected from a drained afforested blanket bog in the Flow Country, Scotland. Short-term mesocosm experiments were conducted by incubating peat, peat + needles and peat + needles + branches with rainwater in quadruplicate. Brash from Sitka spruce (Picea sitchensis) and lodgepole pine (Pinus contorta) was investigated separately, while we also conducted experiments with fresh and aged (â¼18 months) brash. Peat, needles and branches all significantly impacted water quality in the order of branches > needles > peat, while concentrations of DOC, PO43-, NH4+, K and Mn were most impacted. Water quality impacts of spruce brash appeared generally greater than pine, while fresh brash had larger effects than aged brash. In our mesocosms, relative contributions to water quality changes were estimated by elemental yields. On average, peat contributed 25.4% (range 0.6-72.3%), while needles and brash contributed 19.7% (range 3.0-37.0%) and 54.9% (range 22.1-70.2%) to yields, respectively. We further estimate that 267 kg C ha-1 (255.8 kg as DOC, 10.7 kg as DIC), 27.4 kg K ha-1, 5.8 kg P ha-1 (as PO43-) and 0.5 kg N ha-1 (as NH4+) could be released from brash, over nine days.
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Solo , Traqueófitas , Árvores , Qualidade da Água , Áreas Alagadas , Agricultura Florestal , PinusRESUMO
In this study, we develop an artificial intelligence model to predict the vulnerability of broiler production systems (broilers and facilities) to heat conditions using a fuzzy model approach. The model was designed with a multiple-input and a single-output (MISO) approach (input: physical environment and broilers age; output: degree of vulnerability of broilers system). For the validation of the fuzzy model, two approaches were used: (1) records from the scientific literature and (2) meteorological forecasts. First, we validated the model fuzzy with data from the scientific literature; second, we validate the model with data from meteorological forecasts. Both validation approaches were performed in different scenarios of the thermal environment (comfort, discomfort, and discomfort + low heat exchange), broilers' age (21-35 days, 25-39 days, and 28-42 days), and relative cooling efficiency (0% inefficient; and 80% efficient). Then, we applied the model to predict the degree of vulnerability of the broiler system with the help of weather forecasts. The recall and precision of the fuzzy model were high (> 0.9) for the thermal comfort and thermal discomfort + low heat exchange scenarios. In contrast, the fuzzy model was moderate agreement (recall 0.45; precision 0.64) for the thermal discomfort scenario compared to the scientific literature. The application of the model with the weather forecast showed the interaction between the physical and biological systems when submitted to a thermal environment challenge. Regardless of the broilers' age, a high degree of vulnerability was observed in facilities with inefficient cooling system. The fuzzy model developed in this study was efficient to predict the vulnerability of the broiler production system to heat conditions, further, to identify the uncertain conditions associated with broilers' age, relative humidity, and the relative cooling efficiency of the facilities.
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Lógica Fuzzy , Transtornos de Estresse por Calor , Animais , Inteligência Artificial , Galinhas , Tempo (Meteorologia) , Resposta ao Choque Térmico , Transtornos de Estresse por Calor/prevenção & controle , Transtornos de Estresse por Calor/veterináriaRESUMO
The objective of this study was to evaluate carcass characteristics and meat quality of surgically castrated and immunocastrated male pigs. Data were collected from 24 surgically castrated pigs and 24 immunocastrated male entire originating from the commercial line (Agroceres x Topigs), receiving isonutritive diets and were housed in the same experimental shed, slaughtered at 177 days old, with a slaughter weight of 127.8 (± 6.5) and 135.1 (± 7.8) kg, respectively. Carcass and meat quality characteristics such as carcass yield, lean meat yield, fat content, backfat thickness, muscle depth, pH, meat coloring and, drip, thawing and cooking loss, were evaluated. Immunocastrated pigs have heavier carcass, higher meat yield and lower fat thickness when compared to surgically castrated animals. Regarding meat quality, the immunocastrated presented a lighter meat, less reddness and less water holding capacity. In conclusion, this study confirmed that the carcass of male pigs, submitted immunocastration, has lower yield, however, more meat and less fat content, when compared to carcass of male pigs surgically castrated. Meat quality showed peculiar characteristics for immunocastrated pigs, and can be used more for sausage production, since it retains less water and have smaller redness color compared to surgically castrated pigs.
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Composição Corporal , Carne , Animais , Dieta , Masculino , Carne/análise , Orquiectomia/veterinária , SuínosRESUMO
Estimates of peatland carbon fluxes based on remote sensing data are a useful addition to monitoring methods in these remote and precious ecosystems, but there are questions as to whether large-scale estimates are reliable given the small-scale heterogeneity of many peatlands. Our objective was to consider the reliability of models based on Earth Observations for estimating ecosystem photosynthesis at different scales using the Forsinard Flows RSPB reserve in Northern Scotland as our study site. Three sites across the reserve were monitored during the growing season of 2017. One site is near-natural blanket bog, and the other two are at different stages of the restoration process after removal of commercial conifer forestry. At each site we measured small (flux chamber) and landscape scale (eddy covariance) CO2 fluxes, small scale spectral data using a handheld spectrometer, and obtained corresponding satellite data from MODIS. The variables influencing GPP at small scale, including microforms and dominant vegetation species, were assessed using exploratory factor analysis. A GPP model using land surface temperature and a measure of greenness from remote sensing data was tested and compared to chamber and eddy covariance CO2 fluxes; this model returned good results at all scales (Pearson's correlations of 0.57 to 0.71 at small scale, 0.76 to 0.86 at large scale). We found that the effect of microtopography on GPP fluxes at the study sites was spatially and temporally inconsistent, although connected to water content and vegetation species. The GPP fluxes measured using EC were larger than those using chambers at all sites, and the reliability of the TG model at different scales was dependent on the measurement methods used for calibration and validation. This suggests that GPP measurements from remote sensing are robust at all scales, but that the methods used for calibration and validation will impact accuracy.
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ABSTRACT: This study evaluated: (1) the vulnerability of broiler houses with different cooling systems, and (2) the spatial distribution of environmental variables during hot days. Four potentially vulnerable commercial broiler houses in southern Brazil were selected according to the following parameters: absence or presence of different cooling systems, broilers older than 28 days, and outside air dry-bulb temperature over 30°C. Broiler house vulnerability was classified according to the cooling and mechanical ventilation system: cellulose pad cooling (CPC), sprinkling (SPK), fogging (FOG), and mechanical ventilation without evaporative cooling system (VTL). The air dry-bulb temperature (Tdb, °C) and relative humidity (RH, %) were recorded every 10 min. For each broiler house, we evaluated: (1) relative cooling efficiency (RCE) and (2) inside spatial distribution of microclimate variables using a geostatistical technique. The CPC and SPK did not differ (P<0.05) in RCE (81.6% and 80.7%, respectively), but both differed from FOG (23.8%) and VLT (1.87%) systems. The highest variations in indoor Tdb were recorded in the FOG (7 °C), followed by the SPK (4 °C) and CPC (3 °C). In the CPC, there was an increase in RH from the middle to the end of the broiler house near the exhaust fans. In conclusion, the relative cooling efficiency and the inside spatial distributions of environmental variables in the broiler houses were influenced by the existing cooling system.
RESUMO: Os objetivos deste estudo foram (1) comparar a vulnerabilidade de aviários com diferentes sistemas de resfriamento, e (2) avaliar a distribuição espacial interna das variáveis ambientais durante dias quentes. Quatro aviários comerciais potencialmente vulneráveis no sul do Brasil foram selecionados de acordo com os seguintes parâmetros de elegibilidade: ausência ou presença de diferentes sistemas de resfriamento; frangos de corte com mais de 28 dias de idade; e temperatura de bulbo seco do ar externa acima de 30 °C. A vulnerabilidade do aviário foi classificada de acordo com o sistema de resfriamento e ventilação mecânica, sendo: resfriamento por pad cooling (CPC), aspersão (SPK), nebulização (FOG) e ventilação mecânica sem sistema de resfriamento evaporativo (VTL). A temperatura de bulbo seco do ar (Tbs, °C) e a umidade relativa do ar (UR, %) foram coletadas por registradores de dados autônomos a cada 10 min. Para cada aviário foram avaliados: (1) eficiência relativa de resfriamento (RCE) e (2) distribuição espacial interna das variáveis ambientais por técnica de geoestatística. O CPC e SPK não diferiram (P>0,05) na RCE (81,6% e 80,7% respectivamente), mas ambos diferiram do FOG (23,8%) e VLT (1,87%). As maiores variações na Tbs do ar interno foram registradas no FOG (7 °C), seguido pelo SPK (4 °C) e CPC (3 °C). No CPC, houve um aumento da umidade relativa do meio para o final do aviário, próximo aos exaustores. Em conclusão, a eficiência relativa de resfriamento, assim como a distribuição espacial das variáveis ambientais internas foram influenciadas pelo sistema de resfriamento de cada aviário.
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Ocular gene therapy approaches have been developed for a variety of different diseases. In particular, clinical gene therapy trials for RPE65 mutations, X-linked retinoschisis, and choroideremia have been conducted at different centers in recent years, showing that adeno-associated virus (AAV)-mediated gene therapy is safe, but limitations exist as to the therapeutic benefit and long-term duration of the treatment. The technique of vector delivery to retinal cells relies on subretinal injection of the vector solution, causing a transient retinal detachment. Although retinal detachments are known to cause remodeling of retinal neuronal structures as well as significant cell loss, the possible effects of this short-term therapeutic retinal detachment on retinal structure and circuitry have not yet been studied in detail. In this study, retinal morphology and apoptotic status were examined in healthy rat retinas following AAV-mediated gene transfer via subretinal injection with AAV2/5.CMV.d2GFP or sham injection with fluorescein. Outer plexiform layer (OPL) morphology was assessed by immunohistochemical labeling, laser scanning confocal microscopy, and electron microscopy. The number of synaptic contacts in the OPL was quantified after labeling with structural markers. To assess the apoptotic status, inflammatory and pro-apoptotic markers were tested and TUNEL assay for the detection of apoptotic nuclei was performed. Pre- and postsynaptic structures in the OPL, such as synaptic ribbons or horizontal and bipolar cell processes, did not differ in size or shape in injected versus non-injected areas and control retinas. Absolute numbers of synaptic ribbons were not altered. No signs of relevant gliosis were detected. TUNEL labeling of retinal cells did not vary between injected and non-injected areas, and apoptosis-inducing factor was not delocalized to the nucleus in transduced areas. The neuronal circuits in the OPL of healthy rat retinas undergoing AAV-mediated gene transfer were not altered by the temporary retinal detachment caused by subretinal injection, the presence of viral particles, or the expression of green fluorescent protein as a transgene. This observation likely requires further investigations in the dog model for RPE65 deficiency in order to determine the impact of RPE65 transgene expression on diseased retinas in animals and men.
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BACKGROUND: Glioblastoma (GBM), an aggressive brain tumor with frequent relapses and a high mortality, still awaits an effective treatment. Like many cancers, GBM cells acquire oncogenic properties, including metabolic reprogramming, vital for growth. As such, tumor metabolism is an emerging avenue for cancer therapy. One relevant target is the voltage-dependent anion channel 1 (VDAC1), a mitochondrial protein controlling cell energy and metabolic homeostasis. METHODS: We used VDAC1-specific short interfering (si)RNA (si-VDAC1) to treat GBM cell lines and subcutaneous or intracranial-orthotopic GBM xenograft mouse models. Tumors were monitored using MRI, immunohistochemistry, immunoblotting, immunofluorescence, quantitative real-time PCR, transcription factor expression, and DNA microarray analyses. RESULTS: Silencing VDAC1 expression using si-VDAC1 in 9 glioblastoma-related cell lines, including patient-derived cells, led to marked decreases in VDAC1 levels and cell growth. Using si-VDAC1 in subcutaneous or intracranial-orthotopic GBM models inhibited tumor growth and reversed oncogenic properties, such as reprogrammed metabolism, stemness, angiogenesis, epithelial-mesenchymal transition, and invasiveness. In cells in culture, si-VDAC1 inhibits cancer neurosphere formation and, in tumors, targeted cancer stem cells, leading to their differentiation into neuronal-like cells. These VDAC1 depletion-mediated effects involved alterations in transcription factors regulating signaling pathways associated with cancer hallmarks. CONCLUSION: VDAC1 offers a target for GBM treatment, allowing for attacks on the interplay between metabolism and oncogenic signaling networks, leading to tumor cell differentiation into neuron- and astrocyte-like cells. Simultaneously attacking all of these processes, VDAC1 depletion overcame GBM heterogeneity and can replace several anticancer drugs that separately target angiogenesis, proliferation, or metabolism.
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Neoplasias Encefálicas/metabolismo , Glioblastoma/metabolismo , Canal de Ânion 1 Dependente de Voltagem/antagonistas & inibidores , Animais , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/terapia , Linhagem Celular Tumoral , Proliferação de Células , Expressão Gênica , Glioblastoma/genética , Glioblastoma/terapia , Humanos , Masculino , Camundongos Nus , RNA Interferente Pequeno/administração & dosagem , Transcriptoma , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Mutations in the RPE65 gene are associated with autosomal recessive early onset severe retinal dystrophy. Morphological and functional studies indicate early and dramatic loss of rod photoreceptors and early loss of S-cone function, while L and M cones remain initially functional. The Swedish Briard dog is a naturally occurring animal model for this disease. Detailed information about rod and cone reaction to RPE65 deficiency in this model with regard to their location within the retina remains limited. The aim of this study was to analyze morphological parameters of cone and rod viability in young adult RPE65 deficient dogs in different parts of the retina in order to shed light on local disparities in this disease. In retinae of affected dogs, sprouting of rod bipolar cell dendrites and horizontal cell processes was dramatically increased in the inferior peripheral part of affected retinae, while central inferior and both superior parts did not display significantly increased sprouting. This observation was correlated with photoreceptor cell layer thickness. Interestingly, while L/M cone opsin expression was uniformly reduced both in the superior and inferior part of the retina, S-cone opsin expression loss was less severe in the inferior part of the retina. In summary, in retinae of young adult RPE65 deficient dogs, the degree of rod bipolar and horizontal cell sprouting as well as of S-cone opsin expression depends on the location. As the human retinal pigment epithelium (RPE) is pigmented similar to the RPE in the inferior part of the canine retina, and the kinetics of photoreceptor degeneration in humans seems to be similar to what has been observed in the inferior peripheral retina in dogs, this area should be studied in future gene therapy experiments in this model.
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Opsinas dos Cones/genética , Opsinas dos Cones/metabolismo , Retina/metabolismo , Opsinas de Bastonetes/genética , Opsinas de Bastonetes/metabolismo , cis-trans-Isomerases/deficiência , Animais , Cães , Terapia Genética/métodos , Imuno-Histoquímica/métodos , Células Fotorreceptoras Retinianas Cones , Células Fotorreceptoras Retinianas Bastonetes/metabolismo , cis-trans-Isomerases/genética , cis-trans-Isomerases/metabolismoRESUMO
The transcription factor forkhead-box p3 (Foxp3) has been designated as a master regulator for the function of regulatory T cells (Treg). Therefore, the identification of Foxp3 expression in T cells is indispensable for the study of Treg. However, studies on Foxp3 expression in bovine lymphocytes are still sparse, probably due to a lack of Foxp3-specific antibodies with reliable performance in flow cytometry. Our group recently demonstrated that a monoclonal antibody (FJK-16s) developed against murine Foxp3 also binds to porcine Foxp3 and performs well in flow cytometry. A protein sequence alignment of the binding region of the FJK-16s antibody revealed, that within this region the sequences of porcine and bovine Foxp3 are identical. Therefore, we tested this antibody for its suitability in flow cytometry with bovine peripheral blood mononuclear cells (PBMC). By using nonspecific isotype-matched antibodies and competition labeling with non-fluorescent FJK-16s antibodies as negative controls, we readily observed a specific staining of a small subpopulation of CD25(high) lymphocytes within PBMC. Co-staining with monoclonal antibodies against CD3, CD4, CD8ß and TCR-γδ revealed that all Foxp3+ cells co-expressed CD3, and were in their vast majority CD4+. However, minor populations of Foxp3+CD8ß+ and Foxp3+TCR-γδ+ lymphocytes could also be identified. In summary, our data demonstrate that the FJK-16s antibody is a valuable tool to promote the study of Foxp3+ T cells and their biological relevance in cattle.
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Citometria de Fluxo/métodos , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/imunologia , Linfócitos T Reguladores/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais , Especificidade de Anticorpos , Sítios de Ligação/genética , Bovinos , Citometria de Fluxo/estatística & dados numéricos , Fatores de Transcrição Forkhead/metabolismo , Expressão Gênica , Técnicas In Vitro , Masculino , Camundongos , Dados de Sequência Molecular , Sensibilidade e Especificidade , Homologia de Sequência de Aminoácidos , Especificidade da Espécie , Suínos , Linfócitos T Reguladores/metabolismoRESUMO
Rapid immunochromatographic assays for detecting infections with bovine coronavirus (BCV), rotavirus A and Cryptosporidium parvum in calf faeces were evaluated using as gold standards a reverse transcriptase polymerase chain reaction (BCV and rotavirus) and a sedimentation-flotation technique (C. parvum). Rapid tests for the detection of BCV and rotavirus showed a high specificity (96.4% and 95.3%, respectively), but a relatively low sensitivity (60.0% and 71.9%, respectively). Sensitivity and specificity for detection of C. parvum were high (100% and 94.6%, respectively).
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Doenças dos Bovinos/diagnóstico , Coronavirus Bovino/isolamento & purificação , Cryptosporidium parvum/isolamento & purificação , Fezes/parasitologia , Fezes/virologia , Rotavirus/isolamento & purificação , Animais , Animais Recém-Nascidos/parasitologia , Animais Recém-Nascidos/virologia , Bovinos , Doenças dos Bovinos/parasitologia , Doenças dos Bovinos/virologia , Cromatografia , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/veterinária , Criptosporidiose/diagnóstico , Criptosporidiose/veterinária , Imunoensaio/métodos , Imunoensaio/normas , Imunoensaio/veterinária , Contagem de Ovos de Parasitas/veterinária , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/normas , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Infecções por Rotavirus/diagnóstico , Infecções por Rotavirus/veterinária , Sensibilidade e Especificidade , Fatores de TempoRESUMO
We determine and compare the crystal structure of two proteases belonging to the subtilisin superfamily: S41, a cold-adapted serine protease produced by Antarctic bacilli, at 1.4 A resolution and Sph, a mesophilic serine protease produced by Bacillus sphaericus, at 0.8 A resolution. The purpose of this comparison was to find out whether multiple calcium ion binding is a molecular factor responsible for the adaptation of S41 to extreme low temperatures. We find that these two subtilisins have the same subtilisin fold with a root mean square between the two structures of 0.54 A. The final models for S41 and Sph include a calcium-loaded state of five ions bound to each of these two subtilisin molecules. None of these calcium-binding sites correlate with the high affinity known binding site (site A) found for other subtilisins. Structural analysis of the five calcium-binding sites found in these two crystal structures indicate that three of the binding sites have two side chains of an acidic residue coordinating the calcium ion, whereas the other two binding sites have either a main-chain carbonyl, or only one acidic residue side chain coordinating the calcium ion. Thus, we conclude that three of the sites are of high affinity toward calcium ions, whereas the other two are of low affinity. Because Sph is a mesophilic subtilisin and S41 is a psychrophilic subtilisin, but both crystal structures were found to bind five calcium ions, we suggest that multiple calcium ion binding is not responsible for the adaptation of S41 to low temperatures.
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Bacillus/enzimologia , Subtilisinas/química , Animais , Cálcio/metabolismo , Domínio Catalítico , Temperatura Baixa , Cristalografia por Raios X , Modelos Moleculares , Ligação Proteica , Subtilisinas/metabolismoRESUMO
A male, 10 month old llama with malformation of both front limbs was presented. Both front limbs had one more digit located medially. The distal phalanx of this additional digit at the left front limb reached the ground by the tip of the keratinzed pad and the toenail. The accessory digit at the right front limb was bent in a 90 degree angle caudolateraly. Beside the digital bones of the accessory digits the second metacarpal bone and the first carpal bone could be detected in both front limbs by radiological examination. Secondary a bilateral slight carpal valgus deformity could be seen.
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Artrogripose/veterinária , Camelídeos Americanos/anormalidades , Membro Anterior/anormalidades , Polidactilia/veterinária , Falanges dos Dedos do Pé/anormalidades , Animais , Artrogripose/diagnóstico , Artrogripose/diagnóstico por imagem , Masculino , Polidactilia/diagnóstico por imagem , Polidactilia/patologia , RadiografiaRESUMO
The teats of Brown Swiss and Austrian Simmental cows, divided into two groups, one milked by means of an automatic milking system, the other using a conventional milking parlour, were examined monthly by ultrasonography. Aim of the study was to compare the effects of two different milking machines upon the structures of the bovine teat canal and wall by ultrasonography and thereby evaluate ultrasonography as a research tool for visualisation of different influences on the bovine teat. Length and thickness of the teat canal and teat wall thickness were measured and analysed. During lactation, teat canal length and thickness increased in both groups, teat canal length decreased in conventional milked cows at the end of lactation. Shorter and narrower teat canals were observed in automatic milked cows. Differences between the groups in teat canal length and thickness were determined in early lactation. During lactation teat wall thickness showed a slight increase. Automatic milked cows displayed thinner teat walls than cows milked in the milking parlour. Teat morphology was influenced by the number and duration of lactations, milk yield, quarter of the udder and time and date of examination. It was concluded that the effect of the two different milking machines caused significant differences in bovine teat morphology and that ultrasonography proved to be an appropriate method for visualising influences of the milking technique on the bovine teat.
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Bovinos/anatomia & histologia , Bovinos/fisiologia , Indústria de Laticínios , Lactação/fisiologia , Glândulas Mamárias Animais/diagnóstico por imagem , Animais , Indústria de Laticínios/instrumentação , Indústria de Laticínios/métodos , Feminino , Glândulas Mamárias Animais/anatomia & histologia , Glândulas Mamárias Animais/patologia , Leite/metabolismo , UltrassonografiaRESUMO
The objective was to measure teat canal length and diameter, teat diameter and teat wall thickness by ultrasonographic scanning in order to determine the differences in bovine breeds, and to study the influence of teat canal length and diameter on the occurrence of mastitis. A total of 269 lactating dairy cows of four different breeds (Brown Swiss, Simmental, Simmental crossbred with Red Pied, and Holstein-Friesians) from seven Upper Austrian dairy farms were examined. Average teat canal length of Brown Swiss animals was shortest (15.7 mm) followed by Holstein-Friesians (17.2 mm) and Simmental (18.3 mm). These differences in teat canal length were highly significant (P < or = 0.001). There was no significant difference in teat canal length between pure-bred and crossbred Simmentals. Differences of teat canal diameter between breeds were significant (P < or = 0.05). Brown Swiss animals had the largest diameters (2.0 mm) and Holstein-Friesians the smallest (1.7 mm). Differences in teat diameter between Brown Swiss, Holstein-Friesian and Simmental were also significant. No differences were found between the pure-bred and crossbred Simmental cows. The narrowest teats were in Holstein-Friesians and the widest in Simmental. Holstein-Friesians also exhibited the thinnest teat walls while the Simmental had the thickest ones. Teat canal length and diameter were correlated with udder health. Teat canals of healthy udders tended to be longer (17.4 mm) and narrower (1.8 mm) than teat canals of infected udders (15.8 mm, 2.1 mm; P < or = 0.001). A logistic regression model showed significant effects of teat canal length, teat canal diameter and lactation number on udder health.
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Bovinos , Nível de Saúde , Glândulas Mamárias Animais/diagnóstico por imagem , Animais , Bovinos/anatomia & histologia , Feminino , Lactação , Modelos Logísticos , Glândulas Mamárias Animais/anatomia & histologia , Mastite Bovina/diagnóstico por imagem , Especificidade da Espécie , UltrassonografiaRESUMO
We have previously isolated sphericase (Sph), an extracellular mesophilic serine protease produced by Bacillus sphaericus. The Sph amino acid sequence is highly homologous to two cold-adapted subtilisins from Antarctic bacilli S39 and S41 (76% and 74% identity, respectively). Sph is calcium-dependent, 310 amino acid residues long and has optimal activity at pH 10.0. S41 and S39 have not as yet been structurally analysed. In the present work, we determined the crystal structure of Sph by the Eu/multiwavelength anomalous diffraction method. The structure was extended to 0.93A resolution and refined to a crystallographic R-factor of 9.7%. The final model included all 310 amino acid residues, one disulfide bond, 679 water molecules and five calcium ions. Although Sph is a mesophilic subtilisin, its amino acid sequence is similar to that of the psychrophilic subtilisins, which suggests that the crystal structure of these subtilisins is very similar. The presence of five calcium ions bound to a subtilisin molecule, as found here for Sph, has not been reported for the subtilisin superfamily. None of these calcium-binding sites correlates with the well-known high-affinity calcium-binding site (site I or site A), and only one site has been described previously. This calcium-binding pattern suggests that a reduction in the flexibility of the surface loops of Sph by calcium binding may be responsible for its adaptation to mesophilic organisms.
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Bacillus/enzimologia , Serina Endopeptidases/fisiologia , Sequência de Aminoácidos , Sítios de Ligação , Cálcio/química , Cálcio/metabolismo , Temperatura Baixa , Cristalografia por Raios X , Bases de Dados como Assunto , Concentração de Íons de Hidrogênio , Íons , Modelos Químicos , Modelos Moleculares , Dados de Sequência Molecular , Conformação Proteica , Homologia de Sequência de Aminoácidos , Serina Endopeptidases/química , Subtilisina/químicaRESUMO
We have shown that urea-extracted cell wall of entomopathogenic Bacillus sphaericus 2297 and some other strains is a potent larvicide against Culex pipiens mosquitoes, with 50% lethal concentrations comparable to that of the well-known B. sphaericus binary toxin, with which it acts synergistically. The wall toxicity develops in B. sphaericus 2297 cultures during the late logarithmic stage, earlier than the appearance of the binary toxin crystal. It disappears with sporulation when the binary toxin activity reaches its peak. Disruption of the gene for the 42-kDa protein (P42) of the binary toxin abolishes both cell wall toxicity and crystal formation. However, the cell wall of B. sphaericus 2297, lacking P42, kills C. pipiens larvae when mixed with Escherichia coli cells expressing P42. Thus, the cell wall toxicity in strongly toxic B. sphaericus strains must be attributed to the presence in the cell wall of tightly bound 51-kDa (P51) and P42 binary toxin proteins. The synergism between binary toxin crystals and urea-treated cell wall preparations reflects suboptimal distribution of binary toxin subunits in both compartments. Binary toxin crystal is slightly deficient in P51, while cell wall is lacking in P42.