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71.
Roxana Aguilar-Toral Maricela Fernández-Quintero Omar Ortiz-Avila Lucio Hernández de la Paz Elizabeth Calderón-Cortés Alain Raimundo Rodríguez-Orozco Alfredo Saavedra-Molina Marissa Calderón-Torres Christian Cortés-Rojo 《Journal of bioenergetics and biomembranes》2014,46(3):205-220
Increased membrane unsaturation has been associated with shorter longevity due to higher sensitivity to lipid peroxidation (LP) leading to enhanced mitochondrial dysfunction and ROS overproduction. However, the role of LP during aging has been put in doubt along with the participation of electron leak at the electron transport chain (ETC) in ROS generation in aged organisms. Thus, to test these hypothesis and gain further information about how minimizing LP preserves ETC function during aging, we studied the effects of α-linolenic acid (C18:3) on in situ mitochondrial ETC function, ROS production and viability of chronologically aged cells of S. cerevisiae, whose membranes are intrinsically resistant to LP due to the lack of PUFA. Increased sensitivity to LP was observed in cells cultured with C18:3 at 6 days of aging. This was associated with higher viability loss, dissipated membrane potential, impaired respiration and increased ROS generation, being these effects more evident at 28 days. However, at this point, lower sensitivity to LP was observed without changes in the membrane content of C18:3, suggesting the activation of a mechanism counteracting LP. The cells without C18:3 display better viability and mitochondrial functionality with lower ROS generation even at 28 days of aging and this was attributed to full preservation of complex III activity. These results indicate that the presence of PUFA in membranes enhances ETC dysfunction and electron leak and suggest that complex III is crucial to preserve membrane potential and to maintain a low rate of ROS production during aging. 相似文献
72.
Ana Maria V. Pinto José Paulo G. Leite Carlos José Brito Ramos Rainiomar Raimundo da Fonseca Valéria Laneuville Teixeira Izabel Christina N. P. Paixão 《Journal of applied phycology》2014,26(5):2021-2027
Bovine herpesvirus type 5 (BoHV-5) is an important etiologic agent of meningoencephalitis in cattle and has been frequently identified in outbreaks of neurological disease in bovine in the southern hemisphere including Brazil. This study aimed to evaluate the cytotoxic effect and the antiviral properties of extracts obtained from Plocamium brasiliense (Greville) Howe and Taylor in BoHV-5 RJ42/01 replication. The cytotoxic effects were measured in Madin-Darbin bovine kidney cells (MDBK) and cytotoxic concentration (CC50) values have been determined for acyclovir (ACV) (223 μg?±?2.0), ethyl acetate extract from P. brasiliense (2,109 μg?±?10), hexane extract from P. brasiliense (7.181 μg?±?5), dichloromethane extract from P. brasiliense (2.356 μg?±?6.5), and hydroalcoholic extract from P. brasiliense (1.408 μg?±?5.8). As a first approach to characterize the action of these extracts on BoHV-5 RJ42/01, a virucidal assay activity was performed. A virus suspension containing 1?×?105 plaque-forming units (PFU) of the BoHV-5 RJ42/01 was mixed with 600 μg of extract and acyclovir and kept at room temperature (24 °C) for 3 h. Meanwhile, a control of untreated infected virus was performed in the same conditions. Then, treated virus suspension and untreated control were diluted, and percentage of inhibition of infectivity was determined by plaque assay: ethyl acetate extract (99 %), hexane extract (90 %), dichloromethane extract (99 %), and hydroalcoholic extract (27 %). Acyclovir had a slight virucidal activity on viral particle. The inhibition of attachment was performed in MDBK cells inoculated with 100 PFU of BoHV-5 RJ42/01 in the presence or absence of various concentrations of extracts (0.3, 0.9, and 1.5 μg mL?1). Acyclovir was also assayed at 2.8 and 11.25 μg mL?1. The inhibition of adsorption was also tested in MDBK cells treated with the same concentrations of the extracts before virus inoculation. Results: hexane extracts inhibited virus attachment in pre-treated cell 0.9 μg (55 %) and 1.5 μg (71 %) and untreated MDBK cell only with 1.5 μg (63 %). Ethyl acetate extract on cell pre-treated with 0.3 μg (67 %), 0.9 μg (81 %), and 1.5 μg (91 %). Ethyl acetate extract on pre-treated cell 0.3 μg (67 %), 0.9 μg (81 %), and 1.5 (91 %) but discrete inhibition on cell untreated. Dichloromethane extract and acyclovir slightly inhibited virus binding on MDBK cell. 相似文献
73.
Golam Sarwar Raju Md Mizanur Rahman Moghal Mohammad Salim Hossain Md Mahadi Hassan Md Mustahsan Billah Sayed Koushik Ahamed SM Masud Rana 《Biological research》2014,47(1)
Background
The current study aims at evaluating the analgesic, anti-pyretic and anti-inflammatory properties of methanolic extract of the stem, bark and leaves of Launaea sarmentosa and Aegialitis rotundifolia roxb.Results
The AELS and AEAR extract presented a significant (***p < 0.001) dose dependent increase in reaction time in writhing method and showed inhibition of 63.1% and 57.1% respectively at the doses of 400 mg/kg body weight while standard drug showed (P < 0.001) inhibition of 69.23%. In tail immersion method, AELS and AEAR showed maximum time of tail retention at 30 min in hot water i.e. 6.93 sec and 6.54 sec respectively at highest doses of 400 mg/kg body weight than lower dose while standard pentazocine showed reaction time of 7.62 sec. The AELS and AEAR extract also exhibited promising anti-inflammatory effect as demonstrated by statistically significant inhibition of paw volume by 32.48% and 26.75% respectively at the dose of 400 mg/kg body weight while the value at the dose of 200 mg/kg body weight were linear to higher dose at the 3rd hour of study. On the other hand, Standard indomethacin inhibited 40.13% of inflammation (***P < 0.001). In Cotton-pellet granuloma method, AELS and AEAR extract at the dose of 400 mg/kg body weight exhibited inhibition of inflammation of 34.7% and 29.1% respectively while standard drug showed (P < 0.001) inhibition of 63.22%. Intraperitoneal administration of AELS and AEAR showed dose dependent decrease in body temperature in brewer’s yeast induced hyperthermia in rats at both doses. However, AELS significantly decreased body temperature (***p < 0.001) at 400 mg/kg compared to control.Conclusions
Present work propose that the methanolic extract of Launaea sarmentosa and Aegialitis rotundifolia roxb possesses dose dependent pharmacological action which supports its therapeutic use in folk medicine possibly mediated through the inhibition or blocking of release of prostaglandin and/or actions of vasoactive substances such as histamine, serotonin and kinins. 相似文献74.
Salivary gland duct ligation is an alternative to gland excision for treating sialorrhea or reducing salivary gland size prior to tumor excision. Duct ligation also is used as an approach to study salivary gland aging, regeneration, radiotherapy, sialolithiasis and sialadenitis. Reports conflict about the contribution of each salivary cell population to gland size reduction after ductal ligation. Certain cell populations, especially acini, reportedly undergo atrophy, apoptosis and proliferation during reduction of gland size. Acini also have been reported to de-differentiate into ducts. These contradictory results have been attributed to different animal or salivary gland models, or to methods of ligation. We report here a bilateral double ligature technique for rabbit parotid glands with histologic observations at 1, 7, 14, 30, 60 days after ligation. A large battery of special stains and immunohistochemical procedures was employed to define the cell populations. Four stages with overlapping features were observed that led to progressive shutdown of gland activities: 1) marked atrophy of the acinar cells occurred by 14 days, 2) response to and removal of the secretory material trapped in the acinar and ductal lumens mainly between 30 and 60 days, 3) reduction in the number of parenchymal (mostly acinar) cells by apoptosis that occurred mainly between 14–30 days, and 4) maintenance of steady-state at 60 days with a low rate of fluid, protein, and glycoprotein secretion, which greatly decreased the number of leukocytes engaged in the removal of the luminal contents. The main post- ligation characteristics were dilation of ductal and acinar lumens, massive transient infiltration of mostly heterophils (rabbit polymorphonuclear leukocytes), acinar atrophy, and apoptosis of both acinar and ductal cells. Proliferation was uncommon except in the larger ducts. By 30 days, the distribution of myoepithelial cells had spread from exclusively investing the intercalated ducts pre-ligation to surrounding a majority of the residual duct-like structures, many of which clearly were atrophic acini. Thus, both atrophy and apoptosis made major contributions to the post-ligation reduction in gland size. Structures also occurred with both ductal and acinar markers that suggested acini differentiating into ducts. Overall, the reaction to duct ligation proceeded at a considerably slower pace in the rabbit parotid glands than has been reported for the salivary glands of the rat. 相似文献
75.
Effects of Soil Texture on Belowground Carbon and Nutrient Storage in a Lowland Amazonian Forest Ecosystem 总被引:2,自引:1,他引:1
Whendee L. Silver Jason Neff Megan McGroddy Ed Veldkamp Michael Keller Raimundo Cosme 《Ecosystems》2000,3(2):193-209
Soil texture plays a key role in belowground C storage in forest ecosystems and strongly influences nutrient availability
and retention, particularly in highly weathered soils. We used field data and the Century ecosystem model to explore the role
of soil texture in belowground C storage, nutrient pool sizes, and N fluxes in highly weathered soils in an Amazonian forest
ecosystem. Our field results showed that sandy soils stored approximately 113 Mg C ha-1 to a 1-m depth versus 101 Mg C ha-1 in clay soils. Coarse root C represented a large and significant ecosystem C pool, amounting to 62% and 48% of the surface
soil C pool on sands and clays, respectively, and 34% and 22% of the soil C pool on sands and clays to 1-m depth. The quantity
of labile soil P, the soil C:N ratio, and live and dead fine root biomass in the 0–10-cm soil depth decreased along a gradient
from sands to clays, whereas the opposite trend was observed for total P, mineral N, potential N mineralization, and denitrification
enzyme activity. The Century model was able to predict the observed trends in surface soil C and N in loams and sands but
underestimated C and N pools in the sands by approximately 45%. The model predicted that total belowground C (0–20 cm depth)
in sands would be approximately half that of the clays, in contrast to the 89% we measured. This discrepancy is likely to
be due to an underestimation of the role of belowground C allocation with low litter quality in sands, as well as an overestimation
of the role of physical C protection by clays in this ecosystem. Changes in P and water availability had little effect on
model outputs, whereas adding N greatly increased soil organic matter pools and productivity, illustrating the need for further
integration of model structure and tropical forest biogeochemical cycling.
Received 3 March 1999; accepted 27 August 1999. 相似文献
76.
77.
Leonardo Lucas Carnevalli Dias Dimas Mendes Ribeiro Claudete Santa Catarina Raimundo Santos Barros Eny Iochevet Segal Floh Wagner Campos Otoni 《Plant Growth Regulation》2010,62(1):9-19
Ethylene is a plant hormone that is of fundamental importance to in vitro morphogenesis, but in many species, it has not been
thoroughly studied. Its relationship with polyamines has been studied mainly because the two classes of hormones share a common
biosynthetic precursor, S-adenosylmethionine (SAM). In order to clarify whether competition between polyamines and ethylene
influences in vitro morphogenetic responses of Passiflora cincinnata Mast., a climacteric species, different compounds were used that act on ethylene biosynthesis and action, or as ethylene
scavengers. Treatment with the ethylene inhibitor, aminoethoxyvinylglycine (AVG) caused a greater regeneration frequency in
P. cincinnata, whereas treatment with the ethylene precursor, 1-aminocyclopropane-1-carboxylic-acid (ACC) lessened regeneration frequencies.
The data suggested that levels of polyamines and ethylene are not correlated with morphogenic responses in P. cincinnata. It was ascertained that neither the absolute ethylene and polyamine levels, nor competition between the compounds, correlated
to the obtained morphogenic responses. However, sensitivity to, and signaling by, ethylene appears to play an important role
in differentiation. This study reinforces previous reports regarding the requirement of critical concentrations and temporal
regulation of ethylene levels for morphogenic responses. Temporal regulation also appeared to be a key factor in competition
between the two biosynthetic pathways, without having any effects on morphogenesis. Further studies investigating the silencing
or overexpression of genes related to ethylene perception, under the influence of polyamines in cell differentiation are extremely
important for the complete understanding of this process. 相似文献
78.
A mathematical procedure is proposed for the analysis of multivariate data recorded during spectroscopically monitored melting experiments of biomolecules such as nucleic acids and proteins. The method is based on hard/soft hybrid modeling in which one part of the observed variance is explained in terms of a physicochemical model (hard modeling), whereas the other part of the observed variance is explained in terms of soft modeling. The physicochemical model is applied to all of the components related to the unfolding of the biomolecules studied and provides thermodynamic values associated with the unfolding process such as the change in enthalpy, entropy, and melting temperature. The soft modeling term explains the contribution of artifacts not related to the unfolding process such as baseline drifts and nonlinearities. Here the method is applied to the analysis of simulated and experimental data corresponding to the unfolding equilibria of intramolecular structures such as i-motif and G-quadruplex. Overall, the method provides better results than the commonly used univariate approach and also better results than pure hard modeling. 相似文献
79.
Apoptosis of freshly isolated rat hepatocytes was induced by either the omission of fetal bovine serum in the culture medium or addition of the protein kinase C inhibitors polymyxin B or staurosporin. The time-course of DNA breakdown into oligonucleosome-sized fragments and the activity of protein kinase C was determined. Hepatocytes were found to be sensitive to bleomycin which induced a high degree of DNA breakdown even within 30 min incubation. Both staurosporin and polymyxin B induced DNA degradation in hepatocytes after three hours incubation, an effect that was partially prevented by phorbol myristate acetate (PMA). After eight hours incubation, PMA failed to counteract this action and itself produced the apoptosis of rat hepatocytes. The results suggest the involvement of protein kinase C in hepatocyte survival. 相似文献
80.
Homogenization of geographical variants at the nontranscribed spacer of rDNA in Drosophila mercatorum 总被引:2,自引:0,他引:2
rDNA nontranscribed spacer (NTS) lengths of Drosophila mercatorum have been
measured in individuals from several geographic regions. Individuals from
the different geographic subpopulations share some length fragments but are
in general distinct. The length differences, both within and between
individuals, arise from different copy numbers of a 250-bp repeating unit
that is localized to one part of the NTS. In addition to the length
differences caused by the 250-bp repeat, there is a Y chromosome
(male)-specific length variant elsewhere in the NTS that is approximately
70 bp shorter than the NTS fragment from the X chromosome. Sexual
dimorphism seems to be present in all Drosophila. Also, D. mercatorum has
fewer NTS length variants per individual than does D. melanogaster while
possessing comparable levels of restriction- site polymorphism. The
mechanisms that may cause this pattern of variation are selection, gene
conversion, and unequal recombination.
相似文献