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91.
Insect-associated microbes exhibit a wide range of interactions with their hosts. One example of such interactions is the
insect-driven dispersal of microorganisms, which plays an essential role in the ecology of several microbes. To study dispersal
of microorganisms by leaf-cutting ants (Formicidae: Attini), we applied culture-dependent methods to identify the filamentous
fungi and yeasts found in two different body parts of leaf-cutting ant gynes: the exoskeleton and the infrabuccal pocket.
The gynes use the latter structure to store a pellet of the ants’ symbiotic fungus during nest founding. Many filamentous
fungi (n = 142) and yeasts (n = 19) were isolated from the gynes’ exoskeleton. In contrast, only seven filamentous fungi and three yeasts isolates were
recovered from the infrabuccal pellets, suggesting an efficient mechanism utilized by the gynes to prevent contamination of
the symbiotic fungus inoculum. The genus Cladosporium prevailed (78%) among filamentous fungi whereas Aureobasidium, Candida and Cryptococcus prevailed among yeasts associated with gynes. Interestingly, Escovopsis, a specialized fungal pathogen of the leaf-cutting ant-fungus symbiosis, was not isolated from the body parts or from infrabuccal
pellets of any gynes sampled. Our results suggest that gynes of the leaf-cutter ants Atta laevigata and A. capiguara do not vertically transmit any particular species of yeasts or filamentous fungi during the foundation of a new nest. Instead,
fungi found in association with gynes have a cosmopolitan distribution, suggesting they are probably acquired from the environment
and passively dispersed during nest foundation. The possible role of these fungi for the attine ant–microbial symbiosis is
discussed. 相似文献
92.
de Melo Reis RA Ventura AL Schitine CS de Mello MC de Mello FG 《Neurochemical research》2008,33(8):1466-1474
Müller cells represent the main type of glia present in the retina interacting with most, if not all neurons in this tissue.
Müller cells have been claimed to function as optic fibers in the retina delivering light to photoreceptors with minimal distortion
and low loss [Franze et al (2007) Proc Natl Acad Sci 104:8287–8292]. Most of the mediators found in the brain are also detected
in the retinal tissue, and glia cells are active players in the synthesis, release, signaling and uptake of major mediators
of synaptic function. Müller glia trophic factors may regulate many different aspects of neuronal circuitry during synaptogenesis,
differentiation, neuroprotection and survival of photoreceptors, Retinal Ganglion Cells (RGCs) and other targets in the retina.
Here we review the role of several transmitters and trophic factors that participate in the neuron-glia loop in the retina.
Special issue article in honor of Dr. Ricardo Tapia. 相似文献
93.
Kałużna Monika Albuquerque Pedro Tavares Fernando Sobiczewski Piotr Puławska Joanna 《Applied microbiology and biotechnology》2017,101(2):903-903
Applied Microbiology and Biotechnology - 相似文献
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97.
Jean Carlos Santos Fernando A. O. Silveira G. Wilson Fernandes 《Evolutionary ecology》2008,22(1):123-137
The Plant Vigor Hypothesis (PVH) proposes that natural selection on female oviposition choice results from higher fitness
of larvae on more vigorous and larger plant modules. For six consecutive years we tested the PVH predictions by investigating
the effect of shoot size of Bauhinia brevipes (Fabaceae) on the oviposition preference and offspring survival of the gall-midge Schizomyia macrocapillata (Diptera: Cecidomyiidae). Additionally, we analyzed the effects of bottom-up and top-down mortality forces on the system.
The hypersensitive reaction (bottom-up effect) accounted for more than 90% larval mortality of S.
macrocapillata, making available few galls to be found and killed by natural enemies (top-down effect). Smaller shoots were always more
abundant while longer shoots were rare. Nevertheless, the percent number of galls induced by S.
macrocapillata was up to 10-fold greater on the largest shoots, corroborating the preference prediction of the PVH. Schizomyia macrocapillata should use over-exploit larger shoots to maximize the preference for, and consequently increase the performance on these
shoots. Our results partially support the performance prediction of the PVH: (1) the observed survival was higher than expected
on longer shoots, and (2) the ratio of survival per shoot was positively related with shoot length only in 2 years. Thus,
we found a link between female preference and larval performance on large-sized shoots, at least in some years. The gall-midge
attack pattern in this study might be an evolved response to maximize the female preference and increased larval performance
on longer shoots of the host plant. 相似文献
98.
Silva-Brandão KL Lyra ML Santos TV Seraphim N Albernaz KC Pavinato VA Martinelli S Cônsoli FL Omoto C 《Genetics and molecular biology》2011,34(4):719-725
The applicability of mitochondrial nad6 sequences to studies of DNA and population variability in Lepidoptera was tested in four species of economically important moths and one of wild butterflies. The genetic information so obtained was compared to that of cox1 sequences for two species of Lepidoptera. nad6 primers appropriately amplified all the tested DNA targets, the generated data proving to be as informative and suitable in recovering population structures as that of cox1. The proposal is that, to obtain more robust results, this mitochondrial region can be complementarily used with other molecular sequences in studies of low level phylogeny and population genetics in Lepidoptera. 相似文献
99.
Ana C. Coan Brunno M. Campos Clarissa L. Yasuda Bruno Y. Kubota Felipe PG. Bergo Carlos AM. Guerreiro Fernando Cendes 《PloS one》2014,9(1)
Objective
Patients with temporal lobe epilepsy (TLE) with hippocampal sclerosis (HS) have diffuse subtle gray matter (GM) atrophy detectable by MRI quantification analyses. However, it is not clear whether the etiology and seizure frequency are associated with this atrophy. We aimed to evaluate the occurrence of GM atrophy and the influence of seizure frequency in patients with TLE and either normal MRI (TLE-NL) or MRI signs of HS (TLE-HS).Methods
We evaluated a group of 172 consecutive patients with unilateral TLE-HS or TLE-NL as defined by hippocampal volumetry and signal quantification (122 TLE-HS and 50 TLE-NL) plus a group of 82 healthy individuals. Voxel-based morphometry was performed with VBM8/SPM8 in 3T MRIs. Patients with up to three complex partial seizures and no generalized tonic-clonic seizures in the previous year were considered to have infrequent seizures. Those who did not fulfill these criteria were considered to have frequent seizures.Results
Patients with TLE-HS had more pronounced GM atrophy, including the ipsilateral mesial temporal structures, temporal lobe, bilateral thalami and pre/post-central gyri. Patients with TLE-NL had more subtle GM atrophy, including the ipsilateral orbitofrontal cortex, bilateral thalami and pre/post-central gyri. Both TLE-HS and TLE-NL showed increased GM volume in the contralateral pons. TLE-HS patients with frequent seizures had more pronounced GM atrophy in extra-temporal regions than TLE-HS with infrequent seizures. Patients with TLE-NL and infrequent seizures had no detectable GM atrophy. In both TLE-HS and TLE-NL, the duration of epilepsy correlated with GM atrophy in extra-hippocampal regions.Conclusion
Although a diffuse network GM atrophy occurs in both TLE-HS and TLE-NL, this is strikingly more evident in TLE-HS and in patients with frequent seizures. These findings suggest that neocortical atrophy in TLE is related to the ongoing seizures and epilepsy duration, while thalamic atrophy is more probably related to the original epileptogenic process. 相似文献100.
Gutiérrez-Martín Y Martín-Romero FJ Henao F Gutiérrez-Merino C 《Journal of neurochemistry》2005,92(4):973-989
Exposure of cerebellar granule neurones in 25 mm KCl HEPES-containing Locke's buffer (pH 7.4) to 50-100 microm SIN-1 during 2 h decreased the steady-state free cytosolic Ca2+ concentration ([Ca2+]i) from 168 +/- 33 nm to 60 +/- 10 nm, whereas exposure to > or = 0.3 mm SIN-1 produced biphasic kinetics: (i) decrease of [Ca2+]i during the first 30 min, reaching a limiting value of 75 +/- 10 nm (due to inactivation of L-type Ca2+ channels) and (ii) a delayed increase of [Ca2+]i at longer exposures, which correlated with SIN-1-induced necrotic cell death. Both effects of SIN-1 on [Ca2+]i are blocked by superoxide dismutase plus catalase and by Mn(III)tetrakis(4-benzoic acid)porphyrin chloride. Supplementation of Locke's buffer with catalase before addition of 0.5-1 mm SIN-1 had no effect on the decrease of [Ca2+]i but further delayed and attenuated the increase of [Ca2+]i observed after 60-120 min exposure to SIN-1 and also protected against SIN-1-induced necrotic cell death. alpha-Tocopherol, the potent NMDA receptor antagonist (+)-MK-801 and the N- and P-type Ca2+ channels blocker omega-conotoxin MVIIC had no effect on the alterations of [Ca2+]i upon exposure to SIN-1. However, inhibition of the plasma membrane Ca2+ ATPase can account for the increase of [Ca2+]i observed after 60-120 min exposure to 0.5-1 mm SIN-1. It is concluded that L-type Ca2+ channels are a primary target of SIN-1-induced extracellular nitrosative/oxidative stress, being inactivated by chronic exposure to fluxes of peroxynitrite of 0.5-1 microm/min, while higher concentrations of peroxynitrite and hydrogen peroxide are required for the inhibition of the plasma membrane Ca2+ ATPase and induction of necrotic cell death, respectively. 相似文献