RESUMO
Methicillin-resistant Staphylococcus (MRS) has been associated with neonatal infections, with colonization of the anovaginal tract being the main source of vertical transmission. The COVID-19 pandemic has altered the frequency of antibiotic usage, potentially contributing to changes in the dynamics of bacterial agents colonizing humans. Here we determined MRS colonization rates among pregnant individuals attending a single maternity in Rio de Janeiro, Brazil before (January 2019-March 2020) and during (May 2020-March 2021) the COVID-19 pandemic. Anovaginal samples (n = 806 [521 samples before and 285 during the pandemic]) were streaked onto chromogenic media. Colonies were identified by MALDI-TOF MS. Detection of mecA gene and SCCmec typing were assessed by PCR and antimicrobial susceptibility testing was done according to CLSI guidelines. After the onset of the pandemic, MRS colonization rates increased significantly (p < 0.05) from 8.6% (45) to 54.7% (156). Overall, 215 (26.6%) MRS isolates were detected, of which S. haemolyticus was the most prevalent species (MRSH, 84.2%; 181 isolates). SCCmec type V was the most frequent among MRS (63.3%; 136), and 31.6% (68) of MRS strains had a non-typeable SCCmec, due to new combinations of ccr and mecA complexes. Among MRS strains, 41.9% (90) were resistant to at least 3 different classes of antimicrobial agents, and 60% (54) of them were S. haemolyticus harboring SCCmec V. MRS colonization rates and the emergence of multidrug-resistant variants detected in this study indicate the need for continuing surveillance of this important pathogen within maternal and child populations.
Assuntos
COVID-19 , Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Humanos , Feminino , Gravidez , COVID-19/epidemiologia , COVID-19/virologia , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Adulto , Brasil/epidemiologia , Complicações Infecciosas na Gravidez/microbiologia , Complicações Infecciosas na Gravidez/epidemiologia , Antibacterianos/farmacologia , SARS-CoV-2/genética , SARS-CoV-2/isolamento & purificação , Testes de Sensibilidade Microbiana , Pandemias , Vagina/microbiologiaRESUMO
Introduction: The expansion of knowledge about head and neck cancer can provide greater care and the ability to identify risk factors and symptoms of the disease, as well as the incorporation of healthy habits. The younger these concepts are sedimented, the better results will be, making society healthier and more aware. Objective: To assess knowledge about head and neck cancer among adolescents from private schools, aged between 13 and 22 years. Methods: 200 questionnaires were applied among students, about the profile of adolescents and their knowledge about head and neck neoplasms, treatment, and teaching in schools on this topic. The results were analyzed both quantitatively and qualitatively. Results: Only 55 students (29.9%) identified HPV as a risk factor for the disease. 137 students (74.5%) identified the brain as an organ treated by head and neck surgery. As for the therapeutic strategies used for the treatment of neoplasms in the region, only 67 students (36.4%) are aware. On the topic of teaching in schools, 153 students (83.1%) relate to some deficiency in the approach and learning. Conclusion: Knowledge about head and neck cancer is insufficient. It is necessary to introduce in the curriculum basic cancer education in biology classes. The expansion of acquirements about cancer can provide better care and the ability to identify risk factors, initial signs, and symptoms of the disease, as well as the incorporation of healthy habits in families because these students can propagate valid information in their environment.
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Pyrethroids are ectoparasiticides safe for mammals and widely used in farm animals. An outbreak of systemic intoxication with irritant contact dermatitis resulting from the use of cypermethrin pour on in dairy cows is reported in the state of Pernambuco. Eight adult animals were affected, three died on the property and five were referred to the Clínica de Bovinos, Universidade Federal Rural de Pernambuco, Campus Garanhuns. These received 100 mL of pour on Cypermethrin (Ectonil ®, Cipermetrina, Labgard, Brasil). Apathy, hyperexcitability, muscle tremors, sialorrhea, bradycardia and crusted lesions were observed on the dorsum of the neck, scapula, ears and ulcerations in the oral and vaginal mucosa. There was hyperfibrinogenemia and leukocytosis due to neutrophilia with a regenerative left shift. Histopathology showed areas of erosion and ulceration of the epidermis and perivascular lymphohistiocytic and neutrophilic infiltrate in the superficial dermis. Supportive treatment was done with improvement of systemic signs and skin lesions, however, in one animal (with 19 days hospitalized), there was no complete regression of neurological alterations of bradycardia and muscle tremors, even so, it was possible to return to productive activity. High doses of pour on cypermethrin may cause systemic intoxication in cattle and result in bradycardia, hyperexcitability, muscle tremors and sialorrhea with irritant contact dermatitis, and death in severe cases.
Os piretroides são ectoparasiticidas com grande segurança para mamíferos, utilizados amplamente em animais de produção. Relata-se um surto de intoxicação sistêmica com dermatite irritante por contato, resultante do uso de Cipermetrina Pour-On em bovinos, no estado de Pernambuco. Oito animais adultos foram acometidos: três deles morreram na propriedade e cinco foram recebidos na Clínica de Bovinos da Universidade Federal Rural de Pernambuco, Campus Garanhuns. Todos haviam recebido 100mL de Cipermetrina Pour-On (Ectonil®, Cipermetrina, Labgard, Brasil). Observou-se apatia, hiperexcitabilidade, tremores musculares, sialorreia, bradicardia e lesões crostosas no dorso da região de pescoço, na escápula, mas orelhas, bem como ulcerações em mucosa oral e vaginal. No hemograma, verificou-se hiperfibrinogenemia e leucocitose por neutrofilia com desvio à esquerda regenerativo. Na histopatologia, foram constatadas áreas de erosão e ulceração da epiderme e infiltrado linfo-histiocitário e neutrofílico perivascular na derme superficial. O tratamento de suporte gerou melhora dos sinais sistêmicos e das lesões cutâneas, porém, em um dos animais (que esteve internado por 19 dias), não houve regressão completa das alterações neurológicas de bradicardia e de tremores musculares; mesmo assim, foi possível o retorno à atividade produtiva. Doses elevadas de Cipermetrina Pour-On podem causar intoxicação sistêmica em bovinos e resultarem em bradicardia, hiperexcitabilidade, tremores musculares e sialorreia com dermatite irritante por contato, bem como morte em casos severos.
Assuntos
Animais , Bovinos , Intoxicação , Piretrinas/toxicidade , Dermatite de ContatoRESUMO
Esophageal cancer (EC) is an aggressive disease, presenting two main histological subtypes: adenocarcinoma (EAC) and squamous cell carcinoma (ESCC). The two EC subtypes widely differ concerning virtually all factors. ESCC development is mainly associated with tobacco and alcohol abuse, whereas obesity and chronic gastroesophageal reflux disease (GERD) are important risk factors not only for EAC, but also for for Barrett's esophagus (BE), an intestinal metaplasia that precedes EAC. Obesity triggers ectopic lipid droplets (LD) accumulation in non-adipose tissues. LD are organelles involved in cell metabolism, signaling, proliferation and production of inflammatory mediators. Therefore, the aim of this work was to investigate LD occurrence and role in EC. This study shows progressive LD levels increase along EAC development, in esophageal samples from non-obese through obese individuals, as well as BE, and EAC patients, whereas no significant changes were observed in ESCC samples, when compared to non-tumor samples. Additionally, in order to mimic BE and EAC risk factors exposure, a non-tumor esophageal cell line was incubated with oleic acid (OA) and acidified medium and/or deoxycholic acid (DCA), revealing a significant increment in LD amount as well as in COX-2 and CXCL-8 expression, and in IL-8 secretion. Further, COX-2 expression and LD amount presented a significant positive correlation and were detected co-localized in EAC, but not in ESCC, suggesting that LD may be the site for eicosanoid production in EAC. In conclusion, this study shows that obesity, and BE- and EAC-associated inflammatory stimuli result in a gradual increase of LD, that may be responsible for orchestrating inflammatory mediators' production and/or action, thus contributing to BE and EAC genesis and progression.
Assuntos
Adenocarcinoma/metabolismo , Esôfago de Barrett/metabolismo , Ciclo-Oxigenase 2/metabolismo , Neoplasias Esofágicas/metabolismo , Carcinoma de Células Escamosas do Esôfago/metabolismo , Gotículas Lipídicas/metabolismo , Transdução de Sinais/fisiologia , Adenocarcinoma/patologia , Esôfago de Barrett/patologia , Linhagem Celular , Neoplasias Esofágicas/patologia , Carcinoma de Células Escamosas do Esôfago/patologia , Esôfago/metabolismo , Esôfago/patologia , Refluxo Gastroesofágico/metabolismo , Refluxo Gastroesofágico/patologia , Humanos , Inflamação/metabolismo , Inflamação/patologia , Fatores de RiscoRESUMO
We study site- and bond-percolation on a class of lattices referred to as Lieb lattices. In two dimensions the Lieb lattice (LL) is also known as the decorated square lattice, or as the CuO_{2} lattice; in three dimensions it can be generalized to a layered Lieb lattice or to a perovskite lattice. Emergent electronic phenomena, such as topological states and ferrimagnetism, have been predicted to occur in these systems, which may be realized in optical lattices as well as in solid state. Since the study of the interplay between quantum fluctuations and disorder in these systems requires the availability of accurate estimates of geometrical critical parameters, such as percolation thresholds and correlation length exponents, here we use Monte Carlo simulations to obtain these data for LLs when a site (or bond) is present with probability p. We have found that the thresholds satisfy a mean-field (Bethe lattice) trend, namely that the critical concentration, p_{c}, increases as the average coordination number decreases; our estimates for the correlation length exponent are in line with the expectation that there is no change in the universality class.
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A new species of Moniliformis Travassos, 1915 (Acanthocephala: Moniliformidae) is described from the hairy-tailed bolo mouse, Necromys lasiurus Lund, 1840 (Cricetidae: Sigmondontinae), captured in the Brazilian Cerrado, in Uberlândia, state of Minas Gerais, Brazil. The specimens were studied by light and scanning electron microscopy. Molecular phylogenies were inferred from partial nuclear large subunit ribosomal RNA gene sequences and partial mitochondrial cytochrome c oxidase subunit I gene. The new species is distinguished from other moniliformid species by the number of rows and number of hooks per row, size of the proboscis, size of the eggs, host species and geographical distribution. Molecular phylogenies and genetic distances analyses demonstrated that Moniliformis necromysi sp. n. forms a well-supported monophyletic group with sequences of other species of Moniliformis and is distinguished from them, which agrees with the morphological characteristics, allocating the new species to this genus and to the family Moniliformidae Van Cleave, 1924. This is the first moniliformid acanthocephalan described from a wild rodent in Brazil.
Assuntos
Moniliformis/classificação , Moniliformis/ultraestrutura , Sigmodontinae/parasitologia , Animais , Brasil , Feminino , Genes Mitocondriais/genética , Masculino , Microscopia Eletrônica de Varredura , Filogenia , RNA Ribossômico/genéticaRESUMO
It is known that the level of dietary protein modulates the enzymatic activity of the digestive tract of fish; however, its effect at the molecular level on these enzymes and the hormones regulating appetite has not been well characterised. The objective of this study was to evaluate the effect of CP on the activity of proteases and the expression of genes related to the ingestion and protein digestion of juveniles of red tilapia (Oreochromis sp.), as well as the effects on performance, protein retention and body composition of tilapia. A total of 240 juveniles (29.32 ± 5.19 g) were used, distributed across 20 tanks of 100 l in a closed recirculation system. The fish were fed to apparent satiety for 42 days using four isoenergetic diets with different CP levels (24%, 30%, 36% and 42%). The results indicate that fish fed the 30% CP diet exhibited a higher growth performance compared to those on the 42% CP diet (P < 0.05). Feed intake in fish fed 24% and 30% CP diets was significantly higher than that in fish fed 36% and 42% CP diets (P < 0.05). A significant elevation of protein retention was observed in fish fed with 24% and 30% CP diets. Fish fed with 24% CP exhibited a significant increase in lipid deposition in the whole body. The diet with 42% CP was associated with the highest expression of pepsinogen and the lowest activity of acid protease (P < 0.05). The expression of hepatopancreatic trypsinogen increased as CP levels in the diet increased (P < 0.05) up to 36%, whereas trypsin activity showed a significant reduction with 42% CP (P < 0.05). The diet with 42% CP was associated with the lowest intestinal chymotrypsinogen expression and the lowest chymotrypsin activity (P < 0.05). α-amylase expression decreased with increasing (P < 0.05) CP levels up to 36%. No significant differences were observed in the expression of procarboxypeptidase, lipase or leptin among all the groups (P > 0.05). In addition, the diet with 42% CP resulted in a decrease (P < 0.05) in the expression of ghrelin and insulin and an increase (P < 0.05) in the expression of cholecystokinin and peptide yy. It is concluded that variation in dietary protein promoted changes in the metabolism of the red tilapia, which was reflected in proteolytic activity and expression of digestion and appetite-regulating genes.
Assuntos
Ciclídeos , Proteínas Alimentares , Tilápia , Ração Animal/análise , Animais , Ciclídeos/genética , Dieta/veterinária , Expressão Gênica , Tilápia/metabolismoRESUMO
The lack of naturally occurring resistance to citrus psorosis virus (CPsV) necessitates a transgenic approach for the development of CPsV-resistant citrus. To evaluate the feasibility of conferring resistance to a non-transgenic scion, we have assembled citrus plants by grafting combining a non-transgenic Sweet Orange as scion, CPsV-resistant transgenic Sweet Orange lines expressing intron-hairpin (ihp) RNA derived from the viral coat protein (ihpCP) as interstock, and a non-transgenic citrus as rootstock. We demonstrated that ihpCP-transcripts translocate through the graft from interstock to scion, triggering the silencing of coat protein mRNA target. Two independent CPsV challenge assays showed that expression of ihpCP in the interstock provides resistance against CPsV in the interstock, and different levels of protection in the non-tg scion, depending of the virus delivery site. These results indicated that grafting is a promising biotechnological alternative to protect woody plants against virus infections in vegetative propagated plants.
Assuntos
Citrus/imunologia , Imunidade Inata/imunologia , Doenças das Plantas/imunologia , Vírus de Plantas/genética , Plantas Geneticamente Modificadas/imunologia , RNA Mensageiro/genética , Proteínas Virais/genética , Citrus/genética , Citrus/crescimento & desenvolvimento , Citrus/virologia , Doenças das Plantas/genética , Doenças das Plantas/virologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/virologiaRESUMO
New therapeutic approaches are necessary to control strongyloidiasis due to the side effects of, and resistance to, currently available drugs thiabendazole, albendazole, and ivermectin. This study examined the anthelmintic properties of extracts and isolated compounds from Siparuna guianensis against Strongyloides venezuelensis eggs and larvae, using the egg hatching test (EHT) and larval motility test (LMT). Albendazole (0.025 mg/ml) and ivermectin (0.316 mg/ml) were used as the positive controls for the EHT and LMT assays, respectively. Strongyloides venezuelensis eggs or larvae (±50 specimens) were treated with ethanol extract (0.05-1.0 mg/ml), ethyl acetate and aqueous fractions (0.05-0.8 mg/ml), essential oil (0.2-1.0 mg/ml) and α-bisabolol (0.2-1.0 mg/ml) from S. guianensis, and analysed by optical microscopy after 48 h (EHT), or after 24, 48 and 72 h (LMT). All the tested compounds exhibited ovicidal activity equivalent to the positive control and changed the morphology of the eggs. The S. guianensis ethanol extract and aqueous fraction were as effective as the positive control. Phytochemical analysis of the ethanol extract and fractions revealed the presence of phenolic compounds, tannins and flavonoids. Therefore, S. guianensis is effective against S. venezuelensis eggs and larvae in vitro, and can be considered as a potential alternative treatment for strongyloidiasis.
Assuntos
Anti-Helmínticos/farmacologia , Óleos Voláteis/farmacologia , Extratos Vegetais/farmacologia , Strongyloides/efeitos dos fármacos , Traqueófitas/química , Animais , Anti-Helmínticos/química , Larva/efeitos dos fármacos , Sesquiterpenos Monocíclicos/química , Sesquiterpenos Monocíclicos/farmacologia , Óleos Voláteis/química , Óvulo/efeitos dos fármacos , Extratos Vegetais/químicaRESUMO
Protein is the most costly nutrient in fish feed, and while diets offered in the early stages of development typically have high levels of CP, they do not always correspond to the real requirements of the animals. Thus, research that seeks to learn the true nutritional requirements of fish is fundamental to improving commercial fish culture. The present study evaluated the protein requirements of Nile tilapia (Oreochromis niloticus) under larviculture. Fish performance, gene expression for digestive enzymes and their enzymatic activity and stress response to air exposure were analyzed. Four experimental diets differing in CP level were formulated: 30%, 36%, 42% and 48%. Fish larvae were fed the experimental diets during development and sampled 10, 20 and 30 days after the beginning of the experiment for performance, gene expression and enzymatic activity. At sampling time 30, stress resistance was also evaluated by means of an air exposure test. At sampling time 10, CP levels between 36% and 48% could be used for a better performance. During this period, pepsinogen expression was greater for 30% CP, intermediate for 42% and lower for 36% and 48%. After this initial period, diets of between 30% and 42% CP are recommended for better performance. At sampling time 20, gene expression for digestive enzymes and their enzymatic activity were similar for all diets tested. At sampling time 30, the diet of 42% CP induced both greater pepsinogen expression and pepsin activity. Survival after the air exposure test after 30 days of feeding was influenced by CP level in the diet, with the highest survival being for fish fed with 36% CP. Taken together, the present results demonstrate that dietary CP influences digestive enzyme gene expression and activity, and suggest that the best CP levels for Nile tilapia larviculture vary depending on larval stage.
Assuntos
Ração Animal/análise , Ciclídeos/crescimento & desenvolvimento , Dieta/veterinária , Proteínas Alimentares/administração & dosagem , Ração Animal/normas , Fenômenos Fisiológicos da Nutrição Animal , Animais , Ciclídeos/genética , Ciclídeos/metabolismo , Dieta/normas , Regulação Enzimológica da Expressão Gênica , Larva/enzimologia , Larva/genética , Larva/crescimento & desenvolvimentoRESUMO
Two new species of Diaphorocleidus and one new species of Rhinoxenoides n. gen. are described from the gills of Acestrorhynchus falcatus (Bloch) from rivers of north-eastern Pará, Brazil. Diaphorocleidus jaymedeloyolai n. sp. is characterized by a male copulatory organ (MCO) possessing three counterclockwise coils; similar anchors with subtriangular superficial roots; a ventral bar with posteromedial projection; and hooks of pairs 1, 4 and 7 approximately three times longer than hook pair 5. Diaphorocleidus sclerocolpus n. sp. differs from its congeners by a dual-branched accessory piece articulated with the MCO and a sclerotized tubular vagina with a bottle-shaped vestibule. Rhinoxenoides n. gen. is proposed and is characterized by possessing: MCO sclerotized with clockwise coils; an accessory piece articulated to the base of MCO; a sinistroventral vaginal aperture; ventral anchor with conspicuous roots; dorsal anchor with superficial root five times longer than deep root; and absence of dorsal bar. The proposal of Rhinoxenoides n. gen. is also supported by its phylogenetic relationship with Protorhinoxenus prochilodi and species of Rhinoxenus, using 16 morphological characters, which resulted in the following hypothesis of sister-group relationships: Rhinoxenoides n. gen. [Protorhinoxenus (Rhinoxenus curimatae (R. nyttus (R. bulbovaginatus (R. guianensis, R. piranhus, R. euryxenus (R. arietinus, R. anaclaudiae)))))].
Assuntos
Caraciformes/parasitologia , Trematódeos/anatomia & histologia , Trematódeos/classificação , Infecções por Trematódeos/veterinária , Animais , Brasil , Feminino , Doenças dos Peixes/parasitologia , Genitália Masculina , Brânquias/parasitologia , Masculino , Filogenia , Rios/parasitologiaRESUMO
The Holstein model describes the interaction between fermions and a collection of local (dispersionless) phonon modes. In the dilute limit, the phonon degrees of freedom dress the fermions, giving rise to polaron and bipolaron formation. At higher densities, the phonons mediate collective superconducting (SC) and charge-density wave (CDW) phases. Quantum Monte Carlo (QMC) simulations have considered both these limits but have not yet focused on the physics of more general phonon spectra. Here we report QMC studies of the role of phonon dispersion on SC and CDW order in such models. We quantify the effect of finite phonon bandwidth and curvature on the critical temperature T_{cdw} for CDW order and also uncover several novel features of diagonal long-range order in the phase diagram, including a competition between charge patterns at momenta q=(π,π) and q=(0,π) which lends insight into the relationship between Fermi surface nesting and the wave vector at which charge order occurs. We also demonstrate SC order at half filling in situations where a nonzero bandwidth sufficiently suppresses T_{cdw}.
RESUMO
Pterygodermatites (Paucipectines) zygodontomis, a nematode parasite of the small intestine of the rodent Necromys lasiurus, from Uberlândia, Minas Gerais state, Brazil, was analysed by light and scanning electron microscopy. Additionally, phylogenies were inferred from the mitochondrially encoded cytochrome c oxidase I gene (MT-CO1). Details of the helminth surface, such as the oral aperture, cephalic papillae, papillae in the posterior region of the body and longitudinal cuticular elements represented by spine-like projections and fans are presented, adding new taxonomic details. Molecular phylogenetic analysis, based on the MT-CO1, demonstrated that P. (P.) zygodontomis and Pterygodermatites (Paucipectines) jaegerskioldi form a unique evolutionary unit in accordance with the subgenus Paucipectines and corroborated their occurrence in cricetid and didelphid hosts.
Assuntos
Doenças dos Roedores/parasitologia , Sigmodontinae/parasitologia , Infecções por Spirurida/veterinária , Spirurina/classificação , Spirurina/isolamento & purificação , Estruturas Animais/anatomia & histologia , Animais , Brasil , Análise por Conglomerados , Complexo IV da Cadeia de Transporte de Elétrons/genética , Microscopia , Microscopia Eletrônica , Filogenia , Análise de Sequência de DNA , Infecções por Spirurida/parasitologia , Spirurina/anatomia & histologia , Spirurina/genéticaRESUMO
In this paper, we report the development of a novel technique in which the magnetoresistance of nanostructures is perturbatively measured by transversally modulating the DC magnetic field. It measures the electrical transport counterpart of the transverse magnetic AC-susceptibility. The technique was developed in a conventional four-probe configuration in which a small DC current flows through the sample and a small transverse AC-field perturbates the equilibrium position of the sample magnetization. Lock-in detection, in-phase with the AC-perturbation, is used to measure the voltage signal between the two inner electrodes of the four-probe station. We successfully demonstrated that this signal is proportional to the product of the first derivative of sample resistance with respect to the equilibrium position of the magnetization times the second derivative of the energy with respect to the equilibrium position of the magnetization. These dependences add new features to the technique investigated here that were not captured by the investigations previously reported on the same subject. To show the effective use of the technique, we discuss its application in measuring magnetic properties of thin magnetic films in the non-saturated regime.
RESUMO
Com o grande destaque dado para as mudanças climáticas nas últimas décadas, a busca por sistemas de cultivo sustentáveis e equilibrados tem crescido junto com a busca pela conservação do solo e redução do uso de insumos agrícolas inorgânicos. À vista disso, este trabalho teve como objetivo estudar a influência de diferentes culturas consorciadas e em sucessão nos atributos físico-químicos de um Latossolo argiloso em condições de Cerrado. O delineamento experimental foi o de blocos casualizados em esquema fatorial 2 x 2 x 2 e com quatro repetições: semeadura de milho em espaçamento de 0,45 m ou 0,90 m, consorciado com capim-xaraés ou capim-tanzânia, seguido da manutenção da pastagem das forrageiras na área adubadas ou não com 250 kg/ha de N (parcelados em 5 aplicações), e sucedido por soja. Foram determinados os atributos químicos e físicos do solo, resistência mecânica à penetração, umidade gravimétrica e estoque de carbono do solo em quatro épocas: antes da instalação dos consórcios, após a colheita do milho, após a dessecação das pastagens e após a colheita da soja. As parcelas com maior produtividade de matéria seca foram as que resultaram em aumento no teor de matéria orgânica e estoque de carbono do solo e maior ciclagem de nutrientes das camadas mais profundas. Não houve influência do espaçamento do milho nos atributos físicos e químicos do solo. O uso de diferentes espécies simultaneamente na área resulta em redução na resistência mecânica a penetração e aumento da porosidade do solo pelo crescimento diferenciado das raízes.
Because of the great emphasis on climate change in recent decades, the search for sustainable and balanced cropping systems has grown along with the search for soil conservation and reduced use of inorganic farm inputs. From this view, the research was to study the influence of different intercropping and succession in the physical and chemical attributes of a clayey Oxisol in the Cerrado conditions. The experimental design was randomized blocks with treatments: maize seeding spacing of 0.45 m or 0.90 m, intercropped with Xaraés grass or Tanzânia grass, followed by fodder pasture maintenance in the area fertilized or not with 250 kg/ha N (split in 5 applications), and succeeded by soybeans. It was determined the chemical and physical soil attributes, mechanical resistance to penetration, gravimetric humidity and stock of carbon of the soil in four periods: before installing the consortia, after the maize harvest, after drying out the pastures and after soybean harvest. The plots with higher dry matter yield were those that resulted in an increase in organic matter content, soil stock of carbon and greater cycling of nutrients from deeper layers. There was no influence of corn spacing on the physical and chemical soil properties. The use of different species simultaneously in the area results in a reduction in the penetration resistance and increase of the porosity of the soil by differential growth of the roots.
Assuntos
Características do Solo/análise , Indústria Agropecuária/métodos , Poaceae , Química do Solo/análise , Glycine max , Zea mays , Solos ArgilososRESUMO
Com o grande destaque dado para as mudanças climáticas nas últimas décadas, a busca por sistemas de cultivo sustentáveis e equilibrados tem crescido junto com a busca pela conservação do solo e redução do uso de insumos agrícolas inorgânicos. À vista disso, este trabalho teve como objetivo estudar a influência de diferentes culturas consorciadas e em sucessão nos atributos físico-químicos de um Latossolo argiloso em condições de Cerrado. O delineamento experimental foi o de blocos casualizados em esquema fatorial 2 x 2 x 2 e com quatro repetições: semeadura de milho em espaçamento de 0,45 m ou 0,90 m, consorciado com capim-xaraés ou capim-tanzânia, seguido da manutenção da pastagem das forrageiras na área adubadas ou não com 250 kg/ha de N (parcelados em 5 aplicações), e sucedido por soja. Foram determinados os atributos químicos e físicos do solo, resistência mecânica à penetração, umidade gravimétrica e estoque de carbono do solo em quatro épocas: antes da instalação dos consórcios, após a colheita do milho, após a dessecação das pastagens e após a colheita da soja. As parcelas com maior produtividade de matéria seca foram as que resultaram em aumento no teor de matéria orgânica e estoque de carbono do solo e maior ciclagem de nutrientes das camadas mais profundas. Não houve influência do espaçamento do milho nos atributos físicos e químicos do solo. O uso de diferentes espécies simultaneamente na área resulta em redução na resistência mecânica a penetração e aumento da porosidade do solo pelo crescimento diferenciado das raízes.(AU)
Because of the great emphasis on climate change in recent decades, the search for sustainable and balanced cropping systems has grown along with the search for soil conservation and reduced use of inorganic farm inputs. From this view, the research was to study the influence of different intercropping and succession in the physical and chemical attributes of a clayey Oxisol in the Cerrado conditions. The experimental design was randomized blocks with treatments: maize seeding spacing of 0.45 m or 0.90 m, intercropped with Xaraés grass or Tanzânia grass, followed by fodder pasture maintenance in the area fertilized or not with 250 kg/ha N (split in 5 applications), and succeeded by soybeans. It was determined the chemical and physical soil attributes, mechanical resistance to penetration, gravimetric humidity and stock of carbon of the soil in four periods: before installing the consortia, after the maize harvest, after drying out the pastures and after soybean harvest. The plots with higher dry matter yield were those that resulted in an increase in organic matter content, soil stock of carbon and greater cycling of nutrients from deeper layers. There was no influence of corn spacing on the physical and chemical soil properties. The use of different species simultaneously in the area results in a reduction in the penetration resistance and increase of the porosity of the soil by differential growth of the roots.(AU)
Assuntos
Química do Solo/análise , Características do Solo/análise , Indústria Agropecuária/métodos , Glycine max , Zea mays , Poaceae , Solos ArgilososRESUMO
The search for pasture alternatives in livestock farming has focused on options that maximize soil use without exhausting its chemical and physical qualities. Integrated crop-livestock systems (SIPA in the Portuguese acronym) have called the attention of producers since they are economically and ecologically viable. The objective of this study was to measure the influence of corn plant spacing (0.45 and 0.90 m) in forage intercrops (Xaraes or Tanzania grass) on the quality of wet grain silage. A random block design in a 2 x 2 factorial scheme was used, with eight repetitions consisting of the following treatments: corn planted at a row spacing of 0.45 m and intercropped with Xaraes grass; corn planted at 0.90 m and intercropped with Xaraes grass; corn planted at 0.45 m and intercropped with Tanzania grass, and corn planted at 0.90 m and intercropped with Tanzania grass. The contents of dry matter percentage, crude protein, neutral and acid detergent fiber, lignin, cellulose, hemicellulose and soluble carbohydrate and buffering capacity were determined before ensiling and in silage. Ether extract, neutral/acid detergent insoluble nitrogen, ammoniacal nitrogen, pH and in vitro dry matter digestibility were only evaluated in silage. All intercropping modalities studied (forages and spacing) were viable, providing wet grain silage of good quality. However, intercropping of corn with Tanzania grass at a spacing of 0.90 m resulted in higher ether extract content, lower lignin content, and greater digestibility.
A busca por alternativas ao pasto na pecuária tem focado em opções que permitam o uso maximizado do solo sem o esgotamento das qualidades químicas e físicas. O Sistema Integrado de Produção Agropecuária (SIPA) tem chamado a atenção dos produtores por ser econômica como ecologicamente viável. O objetivo deste estudo foi mensurar a influência de espaçamentos de semeadura do milho (0,45 e 0,90 m) em consórcios com forrageiras (capim Xaraés ou capim Tanzânia) na qualidade da silagem de milho de grãos úmidos. O delineamento utilizado foi o de blocos ao acaso, em um fatorial 2 x 2 com oito repetições, composto pelos seguintes tratamentos: milho semeado a 0,45 m entrelinhas e consorciado com capim Xaraés; milho semeado a 0,90 m entrelinhas e consorciado com capim Xaraés; milho semeado a 0,45 m entrelinhas e consorciado com capim Tanzânia; e milho semeado a 0,90 m entrelinhas e consorciado com capim Tanzânia. A porcentagem de matéria seca e os teores de proteína bruta, fibra em detergente neutro e ácido, lignina, celulose, hemicelulose, cinzas, carboidratos solúveis e poder tampão foram determinados tanto no material antes da ensilagem como na silagem. Os teores de extrato etéreo, nitrogênio insolúvel em detergente ácido e neutro, nitrogênio amoniacal, pH e digestibilidade in vitro da matéria seca foram determinados apenas na silagem. Todas as modalidade de consórcio estudado (forrageiras e espaçamentos) foram viáveis em proporcionar silagem de grãos úmidos de boa qualidade, embora o consórcio com capim Tanzânia em espaçamento de 0,90 m proporciou maior teor de extrato etéreo, menor teor de lignina e maior digestibilidade.
Assuntos
Poaceae/crescimento & desenvolvimento , Poaceae/química , Ração Animal/análise , Ração Animal/classificação , Silagem/análise , Zea maysRESUMO
The search for pasture alternatives in livestock farming has focused on options that maximize soil use without exhausting its chemical and physical qualities. Integrated crop-livestock systems (SIPA in the Portuguese acronym) have called the attention of producers since they are economically and ecologically viable. The objective of this study was to measure the influence of corn plant spacing (0.45 and 0.90 m) in forage intercrops (Xaraes or Tanzania grass) on the quality of wet grain silage. A random block design in a 2 x 2 factorial scheme was used, with eight repetitions consisting of the following treatments: corn planted at a row spacing of 0.45 m and intercropped with Xaraes grass; corn planted at 0.90 m and intercropped with Xaraes grass; corn planted at 0.45 m and intercropped with Tanzania grass, and corn planted at 0.90 m and intercropped with Tanzania grass. The contents of dry matter percentage, crude protein, neutral and acid detergent fiber, lignin, cellulose, hemicellulose and soluble carbohydrate and buffering capacity were determined before ensiling and in silage. Ether extract, neutral/acid detergent insoluble nitrogen, ammoniacal nitrogen, pH and in vitro dry matter digestibility were only evaluated in silage. All intercropping modalities studied (forages and spacing) were viable, providing wet grain silage of good quality. However, intercropping of corn with Tanzania grass at a spacing of 0.90 m resulted in higher ether extract content, lower lignin content, and greater digestibility.(AU)
A busca por alternativas ao pasto na pecuária tem focado em opções que permitam o uso maximizado do solo sem o esgotamento das qualidades químicas e físicas. O Sistema Integrado de Produção Agropecuária (SIPA) tem chamado a atenção dos produtores por ser econômica como ecologicamente viável. O objetivo deste estudo foi mensurar a influência de espaçamentos de semeadura do milho (0,45 e 0,90 m) em consórcios com forrageiras (capim Xaraés ou capim Tanzânia) na qualidade da silagem de milho de grãos úmidos. O delineamento utilizado foi o de blocos ao acaso, em um fatorial 2 x 2 com oito repetições, composto pelos seguintes tratamentos: milho semeado a 0,45 m entrelinhas e consorciado com capim Xaraés; milho semeado a 0,90 m entrelinhas e consorciado com capim Xaraés; milho semeado a 0,45 m entrelinhas e consorciado com capim Tanzânia; e milho semeado a 0,90 m entrelinhas e consorciado com capim Tanzânia. A porcentagem de matéria seca e os teores de proteína bruta, fibra em detergente neutro e ácido, lignina, celulose, hemicelulose, cinzas, carboidratos solúveis e poder tampão foram determinados tanto no material antes da ensilagem como na silagem. Os teores de extrato etéreo, nitrogênio insolúvel em detergente ácido e neutro, nitrogênio amoniacal, pH e digestibilidade in vitro da matéria seca foram determinados apenas na silagem. Todas as modalidade de consórcio estudado (forrageiras e espaçamentos) foram viáveis em proporcionar silagem de grãos úmidos de boa qualidade, embora o consórcio com capim Tanzânia em espaçamento de 0,90 m proporciou maior teor de extrato etéreo, menor teor de lignina e maior digestibilidade.(AU)
Assuntos
Poaceae/química , Poaceae/crescimento & desenvolvimento , Silagem/análise , Ração Animal/análise , Ração Animal/classificação , Zea maysRESUMO
Mercury exposure is considered to be a public health problem due to the generation of toxic effects on human health as a result of environmental and occupational conditions. The inorganic form of mercury (HgCl2) can cause several biological changes in cells and tissues through its cumulative toxic potential, but little has been experimentally proven about the effects of inorganic mercury on salivary glands, an important modulator organ of oral health. This study analyzes the effects of prolonged low dose exposure to HgCl2 on the salivary glands of rats. Adult animals received a dose of 0.375 mg kg-1 day-1 over a period of 45 days. The parotid and submandibular glands were collected for analysis of the mercury levels and evaluation of oxidative stress, histological parameters and immunomodulation for metallothionein I and II (MT-I/II). In this investigation, biochemical and tissue changes in the salivary glands were verified due to the mercury levels, causing reduction in antioxidant capacity against peroxyl radicals, with consequent cellular lipid peroxidation and an increase in nitrite levels, volumetric changes and cytoskeletal damage in the submandibular glands, with less severe damage to the parotid glands. The results also have shown the occurrence of a cytoprotection mechanism due to increased MT-I/II expression, but not enough to avoid the morphology and oxidative damage. This evidence highlights, for the first time, that inorganic mercury is able to alter the morphology and oxidative biochemistry in salivary glands when exposed for a long time in low doses.