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41.
Subterranean termites have highly cryptic life habits and their foraging activities are as a rule confined to below-ground level gallery systems. Mark–release–recapture (MRR) using fat-soluble histological dyes is a candidate method for the study of foraging dynamics and territories, but has not hitherto been standardized experimentally. A wide range of dye types and concentrations is reported in the literature. In this study, six potential dyes were evaluated at different concentrations for marking workers of Reticulitermes grassei (Clément) (Isoptera: Rhinotermitidae), under laboratory and simulated field conditions. Neutral red (1% wt/wt) was considered the most effective while showing acceptably low toxicity. In a subsequent field trial using dye impregnated into a wooden bait, the MMR procedure was used to map the foraging territory perimeter of a single colony. Assumptions inherent in the interpretation of MMR data are reviewed. To map the foraging territory perimeter by this method, two theoretical approaches are defined (a conservative and a non-conservative hypothesis). We show that the approach adopted may affect the estimate obtained by as much as 100%. Results are discussed in the context of the ecology and behaviour of subterranean termite colonies. 相似文献
42.
Alexandra Souza dos Santos Marcos Alexandre Nobre Lemos Carlos Augusto Pereira Soraia Attie Calil Jorge Dr. 《Biotechnology journal》2009,4(11):1578-1581
The aim of this study was to achieve expression of recombinant rabies virus glycoprotein (rRVGP) in Drosophila S2 cells. For this, a cDNA coding for the selection hygromycin antibiotic and the cDNA encoding the RVGP protein under the control of the constitutive actin promoter (Ac) were cloned in an expression plasmid, which was transfected into S2 cells. S2 cell populations (S2AcRVGPHy) showed rRVGP expression in cell lysates, attaining concentrations up to 1.5 μg/107 cells (705 μg/L). Of the transfected cells, 20% were shown to express the rRVGP. Cell subpopulations selected by limiting dilution expressed higher rRVGP yields and 90% of the cells were shown to express the rRVGP. Cell populations re-selected by addition of hygromycin were shown to express 10 times higher rRVGP yields. The data presented here show that Drosophila S2 cells can be efficiently transfected with an expression/selection plasmid for rRVGP expression, allowing its synthesis with a high degree of physical and biological integrity. The importance of subpopulation selection was indicated by the increasing rRVGP yields during these procedures. 相似文献
43.
Pavinatto FJ Pavinatto A Caseli L Santos DS Nobre TM Zaniquelli ME Oliveira ON 《Biomacromolecules》2007,8(5):1633-1640
In this paper we employed phospholipid Langmuir monolayers as membrane models to probe interactions with chitosan. Using a combination of surface pressure--area and surface potential--area isotherms and rheological measurements with the pendent drop technique, we observed that chitosan interacts with phospholipid molecules at the air-water interface. We propose a model in which chitosan interacts with the phospholipids mainly through electrostatic interactions, but also including H-bonding and hydrophobic forces, depending on the phospholipid packing density. At large areas per molecule, chitosan in the subphase adsorbs onto the monolayer, expanding it. At small areas per molecule, chitosan is located in the subsurface. Indeed, a mixed chitosan-phospholipid monolayer can be transferred onto solid supports, even at high surface pressures. The effects of chitosan on the viscoelastic properties of phospholipid monolayers may be taken as evidence for the ability of chitosan to disrupt cell membranes. 相似文献
44.
45.
L Albuquerque FA Rainey MF Nobre MS da Costa 《Systematic and applied microbiology》2012,35(6):385-389
Two isolates, designated PRQ-67T and PRQ-68, with an optimum growth temperature of about 50 °C, growth range in medium containing between 1 and 9% NaCl and an optimum pH for growth between 7.5 and 8.0, were recovered from a shallow marine hot spring on a beach, Praia do Fogo, at Ribeira Quente, on the Island of São Miguel in the Azores. Comparisons of 16S rRNA gene sequences show these strains to be most closely related (93.1–94.7% similarity) to species of the genus Amaricoccus, within the family Rhodobacteraceae. Strains are non-pigmented and form non-motile pleomorphic cells that stain Gram-negative, are aerobic, oxidase and catalase positive. The major fatty acids are C18:1ω7c and C18:1ω7c 11-methyl. Ubiquinone 10 is the major respiratory quinone. Major polar lipids are phosphatidylcholine, phosphatidylglycerol and one aminolipid. Based on 16S rRNA gene sequence analysis, physiological and biochemical characteristics we describe a new species of a novel genus represented by strain PRQ-67T (=DSM 22673T = LMG 25334T) for which we propose the name Oceanicella actignis. 相似文献
46.
47.
Subterranean termites (Reticulitermes grassei) were surveyed over successive seasons in a managed eucalyptus plantation in southeastern Portugal for 26 months. Termite activity in seven diameter categories of lying dead wood was investigated by a modified line intersection method (LIS). Each item sampled was inspected and assessed for termite attack and for general (i.e. fungal) decay status using standard protocols. Line intersection is quantitative to the extent that it can link foraging and decay parameters to woody biovolume. It was found that termites selected items with larger diameter, the observed trend showing an exponential character with greater termite attack as diameter increased. Attack by termites was positively associated with prior decay by fungi. A clear positive relationship was shown between rainfall and total woody biovolume containing live termites, underlining the importance of moisture for termite activity. Subterranean termites appeared to be important wood decomposers in the woodland studied, with an average of 30% of lying dead wood branches showing signs of termite attack. 相似文献
48.
Luciana Albuquerque Fred A. Rainey Aldina Pena Igor Tiago António Veríssimo M. Fernanda Nobre Milton S. da Costa 《Systematic and applied microbiology》2010
Two isolates, with an optimum growth temperature of about 45–50 °C and an optimum pH for growth between 7.5 and 8.5, were recovered from a hot spring in the Furnas area on the Island of São Miguel in the Azores. Strains form irregular rod-shaped cells are motile and stain Gram negative. The cells multiply by budding. These strains are non-pigmented, strictly aerobic, catalase and oxidase positive. These organisms assimilated carbohydrates, organic acids and amino acids. The major fatty acids are 19:0cyclo ω8c and 18:0. Ubiquinone 10 is the major respiratory quinone. The major polar lipids are diphosphatidylglycerol, phosphatidylmonomethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylcholine in addition to one unidentified aminolipid and one unidentified glycolipid. Bacteriochlorophyll a, puf genes and RuBisCo genes were not detected. Analysis of the 16S rRNA gene shows the strains to cluster with species of the genera Afifella, Rhodobium, Anderseniella and Amorphus to which they have sequence similarity in the range 93–94%. Based on 16S rRNA gene sequence analysis, physiological and biochemical characteristics we describe a new species of a novel genus represented by strain CB-27AT (=DSM 19345T=LMG 24113T) for which we propose the name Tepidamorphus gemmatus. 相似文献
49.
Hélio Vitoriano Nobre Geanne Matos de Andrade Cunha Lissiana Magna de Vasconcelos Hemerson Iury Ferreira Magalhães Raimundo Nogueira Oliveira Neto Flávio Damasceno Maia Manoel Odorico de Moraes L. Kalyne A. Moreira Leal Glauce Socorro de Barros Viana 《Neurochemistry international》2010,56(1):51-58
In this study, the cytoprotective effects of caffeine (CAF) and 8-(3-chlorostyryl)-caffeine (CSC), A2A receptor antagonists, were tested against 6-OHDA-induced cytotoxicity, in rat mesencephalic cells. Both drugs significantly increased the number of viable cells, after their exposure to 6-OHDA, as measured by the MTT assay. While nitrite levels in the cells were drastically increased by 6-OHDA, their concentrations were brought toward normality after CAF or CSC, indicating that both drugs block 6-OHDA-induced oxidative stress which leads to free radicals generation. A complete blockade of 6-OHDA-induced lipid peroxidation, considered as a major source of DNA damage, was observed after cells treatment with CAF or CSC. 6-OHDA decreased the number of normal cells while increasing the number of apoptotic cells. In the CAF plus 6-OHDA group, a significant recover in the number of viable cells and a decrease in the number of apoptotic cells were seen, as compared to the group treated with 6-OHDA alone. A similar effect was observed after cells exposure to CSC in the presence of 6-OHDA. Unexpectedly, while a significant lower number of activated microglia was observed after cells exposure to CAF plus 6-OHDA, this was not the case after cells exposure to CSC under the same conditions. While CAF lowered the percentage of reactive astrocytes increased by 6-OHDA, CSC presented no effect. The effects of these drugs were also examined on the releases of myeloperoxidase (MPO), an inflammatory marker, and lactate dehydrogenase (LDH), a marker for cytotoxicity, in human neutrophils, in vitro. CSC and CAF (0.1, 1 and 10 μg/ml) produced inhibitions of the MPO release from PMA-stimulated cells, ranging from 45 to 83%. In addition, CSC and CAF (5, 50 and 100 μg/ml) did not show any cytotoxicity in the range of concentrations used, as determined by the LDH assay. All together, our results showed a strong neuroptrotection afforded by caffeine or CSC, on rat mesencephalic cells exposed to 6-OHDA. Furthermore, CSC and caffeine actions, inhibiting MPO as well as LDH releases, would contribute to their possible benefit in the treatment of neurodegenerative diseases, including DP. These effects are partially due to the ability of these A2A antagonists to decrease the cells free radicals production and oxidative stress, that are major components of 6-OHDA-induced cytotoxicity. 相似文献
50.
Sonali Vora Asad Abbas Chong J Kim Taryn LS Summerfield Juan P Kusanovic Jay D Iams Roberto Romero Douglas A Kniss William E AckermanIV 《Reproductive biology and endocrinology : RB&E》2010,8(1):8