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101.
Determinism of bacterial metacommunity dynamics in the southern East China Sea varies depending on hydrography 下载免费PDF全文
Yi‐Chun Yeh Pedro R. Peres‐Neto Shiao‐Wei Huang Yung‐Chih Lai Chen‐Yi Tu Fuh‐Kwo Shiah Gwo‐Ching Gong Chih‐hao Hsieh 《Ecography》2015,38(2):198-212
Spatial variation of communities composition (metacommunities) results from multiple assembly mechanisms, including environmental filtering and dispersal; however, whether and why the relative importance of the assembly mechanisms in shaping bacterial metacommunity changes through time in marine pelagic systems remains poorly studied. Here, we applied the elements of metacommunity structure framework and the variation partitioning framework to examine whether temporal variation of hydrographic conditions influences bacterioplankton metacommunity dynamics in the southern East China Sea (ECS). The spatiotemporal variation of bacterial communities composition was revealed using 454 pyrosequencing of 16S rDNA. In addition to the whole bacterial community, we analyzed four dominant taxonomic groups (Cyanobacteria, Alphaproteobacteria, Gammaproteobacteria, and Actinobacteria) separately. Our analyses indicate that, considering the whole community level, the determinism of metacommunity structure varied among seasons. When the degree of connectivity was low (December), the metacommunity exhibited random distribution and was explained mainly by the environmental component. However, Clementsian metacommunity was found at intermediate connectivity (May), during which the environmental and spatial predictors were both significant. When connectivity was high (August), a random distribution pattern was found and no significant effect of environmental filtering or dispersal limitation was detected. Nevertheless, when considering different taxonomic groups, the differences in metacommunity dynamics among groups were found. Our results suggest that the driving forces of metacommunity dynamics varied depending on hydrography, as the degrees of environmental heterogeneity and connectivity among habitat patches were determined by circulation pattern. Moreover, mechanisms varied among different taxonomic groups, suggesting that differential dispersal capacity among taxonomic groups should be integrated into community assembly studies. 相似文献
102.
Rodrigo Araújo Lima Rodrigues Ludmila Karen dos Santos Silva Fábio Pio Dornas Danilo Bretas de Oliveira Thais Furtado Ferreira Magalh?es Daniel Assis Santos Adriana Oliveira Costa Luiz de Macêdo Farias Paula Prazeres Magalh?es Cláudio Ant?nio Bonjardim Erna Geessien Kroon Bernard La Scola Juliana Reis Cortines J?natas Santos Abrah?o 《Journal of virology》2015,89(23):11812-11819
103.
104.
Jabari S da Silveira AB de Oliveira EC Neto SG Quint K Neuhuber W Brehmer A 《Histochemistry and cell biology》2011,135(1):47-57
One frequent chronic syndrome of Chagas’ disease is megacolon, an irreversible dilation of a colonic segment. Extensive enteric
neuron loss in the affected segment is regarded as key factor for deficient motility. Here, we assessed the quantitative balance
between cholinergic and nitrergic neurons representing the main limbs of excitatory and inhibitory colonic motor innervation,
respectively. From surgically removed megacolonic segments of four patients, each three myenteric wholemounts (from non-dilated
oral, megacolonic and non-dilated anal parts) was immunohistochemically triple-stained for choline acetyltransferase, neuronal
nitric oxide synthase (NOS) and the panneuronal human neuronal protein Hu C/D. Degenerative changes were most pronounced in
the megacolonic and anal regions, e.g. bulked, honeycomb-like ganglia with few neurons which were partly enlarged or atrophic
or vacuolated. Neuron counts from each 15 ganglia of 12 megacolonic wholemounts were compared with those of 12 age- and region-matched
controls. Extensive neuron loss, mainly in megacolonic and anal wholemounts, was obvious. In all three regions derived from
megacolonic samples, the proportion of NOS-positive neurons (control: 55%) was significantly increased: in non-dilated oral
parts to 61% (p = 0.003), in megacolonic regions to 72% (p < 0.001) and in non-dilated anal regions to 78% (p < 0.001). We suggest the chronic dilation of megacolonic specimens to be due to the preponderance of the nitrergic, inhibitory
input to the intestinal muscle. However, the observed neuronal imbalance was not restricted to the dilated regions: the non-dilated
anal parts may be innervated by ascending, cholinergic axons emerging from less affected, more anally located regions. 相似文献
105.
Guedes FL de Oliveira BG Hernandes MZ De Simone CA Veiga FJ de Lima Mdo C Pitta IR Galdino SL Neto PJ 《AAPS PharmSciTech》2011,12(1):401-410
Solid dispersions have been used as a strategy to improve the solubility, dissolution rate, and bioavailability of poor water-soluble
drugs. The increase of the dissolution rate presented by (5Z)-3-(4-chloro-benzyl)-5-(4-nitro-benzylidene)-imidazolidine-2,4-dione (LPSF/FZ4) from the solid dispersions is related to
the existence of intermolecular interactions of hydrogen bond type (>N–H...O<) between the amide group (>N–H) of the LPSF/FZ4 and the ether group (–O–) of the polyethyleneglycol polymer, or the carbonyl
(C=O) of the polyvinylpyrrolidone polymer (PVP). The intensity of these interactions is directly reflected in the morphology
acquired by LPSF/FZ4 in these systems, where a new solid phase, in the form of amorphous aggregates of irregular size, was
identified through scanning electron microscopy and confirmed in the characterizations achieved using X-ray diffraction and
thermal analysis of DSC. The solid dispersions with the polymer PVP, in higher concentrations, were revealed to be the best
option to be used in the formulations of LPSF/FZ4 in both theoretical and experimental studies. 相似文献
106.
Trovatti E Silva NH Duarte IF Rosado CF Almeida IF Costa P Freire CS Silvestre AJ Neto CP 《Biomacromolecules》2011,12(11):4162-4168
Biocellulose (BC) is a highly pure form of cellulose, produced in the form of a swollen membrane, with several applications in the biomedical area. In this study, the behavior of BC membranes as systems for topical delivery of lidocaine was evaluated. The BC-lidocaine membranes were prepared and characterized in terms of structural and morphological properties. A uniform distribution of the drug inside the BC membranes was observed. In vitro diffusion studies with Franz cells were conducted using human epidermal membranes and showed that the permeation rate of the drug in BC membranes was slightly slower than that obtained with the conventional systems, which was attributed to the establishment of interactions between the lidocaine molecules and the BC membrane, as evidenced by FTIR and NMR analysis. These results indicate that this methodology can be successfully applied for the dermal administration of lidocaine regarding the release profile and ease of application. 相似文献
107.
Paiotti AP Miszputen SJ Oshima CT Artigiani Neto R Ribeiro DA Franco M 《Journal of molecular histology》2011,42(5):443-450
Crohn′s disease (CD) is associated with gut barrier dysfunction. Tumour necrosis factor-α (TNF-α) plays an important role
into the pathogenesis of several inflammatory diseases because its expression is increased in inflamed mucosa of CD patients.
Anti-TNF therapy improves significantly mucosal inflammation. Thus, this study aimed to evaluate the effect of Etanercept
(ETC), a tumour necrosis factor alpha (TNF-α) antagonist on the 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced experimental
colitis. A total of 18 Wistar rats were randomized into four groups, as follows: (1) Sham: sham induced-colitis; (2) TNBS:
non-treated induced-colitis; (3) ETC control; (4) ETC-treated induced-colitis. Rats from group 4 presented significant improvement
either of macroscopic or of histopathological damage in the distal colon. The gene expression of TNF-α mRNA, decreased significantly
in this group compared to the TNBS non-treated group. The treatment with etanercept attenuated the colonic damages and reduced
the inflammation caused by TNBS. Taken together, our results suggest that ETC attenuates intestinal colitis induced by TNBS
in Wistar rats by TNF-α downregulation. 相似文献
108.
Carolina A. Lima José L. Lima Filho Benício B. Neto Attilio Converti Maria G. Carneiro da Cunha Ana L. F. Porto 《Biotechnology and Bioprocess Engineering》2011,16(3):549-560
A 24 full factorial design was used to identify the main effects and interactions of the initial medium pH, soybean flour concentration,
temperature and orbital agitation speed on extracellular collagenase production by Penicillium aurantiogriseum URM4622. The most significant variables for collagenase production were soybean flour concentration and initial medium pH
that had positive main effects, and temperature that had a negative one. Protein concentration in soybean flour revealed to
be a significant factor for the production of a collagenase serine proteinase. The most favorable production conditions were
found to be 0.75% soybean flour, pH 8.0, 200 rpm, and 28°C, which led to a collagenase activity of 164 U. The enzyme showed
an optimum activity at 37°C and pH 9.0, was stable over wide ranges of pH and temperature (6.0 ∼ 10.0 and 25 ∼ 45°C, respectively)
and was strongly inhibited by 10 mM phenylmethylsulphonylfluoride. The firstorder rate constants for collagenase inactivation
in the crude extract, calculated from semi-log plots of the residual activity versus time, were used in Arrhenius and Eyring
plots to estimate the main thermodynamic parameters of thermoinactivation (E*
d
= 107.4 kJ/mol and ΔH*
d
= 104.7 kJ/mol). The enzyme is probably an extracellular neutral serine collagenase effective on azocoll, gelatin and collagen
decomposition. 相似文献
109.
110.