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Bacterial endosymbionts play important roles in ecological traits of aphids.In this study,we characterize the bacterial endosymbionts of A.gossypii collected in Karaj,Iran and their role in the performance of the aphid.Our results indicated that beside Buchnera aphidicola,A.gossypii,also harbors both Hamiltonella defensa and Arsenophonus sp.Quantitative PCR(qPCR)results revealed that the populations of the endosymbionts increased throughout nymphal development up to adult emergence;thereafter,populations of Buchnera and Arsenophonus were diminished while the density of H.defensa constantly increased.Buchnera reduction caused prolonged development and no progeny production.Furthermore,secondary symbiont reduction led to reduction of the total life span and intrinsic rate of natural increase as well as appearance of the deformed dead offspring in comparison with the control insects.Reduction of the secondary symbionts did not affect parasitism rate of the aphid by the parasitic wasp Aphidius matricariae.Together these findings showed that H.defensa and Arsenophonus contributed to the fitness of A.gossypii by enhancing its performance,but not through parasitoid resistance. 相似文献
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Dizaji MZ Malehmir M Ghavamzadeh A Alimoghaddam K Ghaffari SH 《Neurochemical research》2012,37(2):370-380
Patients with glioblastoma multiforme (GBM) have poor therapeutic outcomes despite their current therapy. In an attempt to
increase the efficacy of therapy for GBM, we studied the efficacy of arsenic trioxide (ATO), a newly introduced treatment
for glioma, combined with silibinin, a natural polyphenolic flavonoid, in the GBM cell line, U87MG. The combination therapy
synergically inhibited metabolic activity, cell proliferation, and gelatinase A and B activities; it also increased apoptosis.
Additionally, it decreased the mRNA level of cathepsin B, uPA, matrix metalloproteinase-2 and 9, membrane type 1-MMP, survivin,
BCL2, CA9; it increased mRNA level of caspase-3. Altogether, these results showed that ATO and silibinin in some cases improved
and/or complemented the anticancer effects. This study may supply insight into the design of new combination cancer therapies
to cells intrinsically less sensitive to routine therapies and suggested a new combination therapy for the highly invasive
human glioma treatment. 相似文献
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Haplotypes include essential SNP information used for a variety of purposes such as investigating potential links between certain diseases and genetic variations. Given a set of genotypes, the haplotype inference problem based on pure parsimony is the problem of finding a minimum set of haplotypes that explains all the given genotypes. The problem is especially important because, while it is fairly inexpensive to obtain genotypes, other approaches to obtaining haplotypes are significantly expensive. There are two types of methods proposed for the problem, namely exact and inexact methods. Existing exact methods guarantee obtaining purely parsimonious solutions but have exponential time-complexities and are not practical for large number or length of genotypes. However, inexact methods are relatively fast but do not always obtain optimum solutions. In this paper, an improved heuristic is proposed, based on which new inexact and exact methods are provided. Experimental results indicate that the proposed methods replace the state-of-the-art inexact and exact methods for the problem. 相似文献
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Constantino PJ Lee JJ Gerbig Y Hartstone-Rose A Talebi M Lawn BR Lucas PW 《American journal of physical anthropology》2012,148(2):171-177
Primate teeth adapt to the physical properties of foods in a variety of ways including changes in occlusal morphology, enamel thickness, and overall size. We conducted a comparative study of extant primates to examine whether their teeth also adapt to foods through variation in the mechanical properties of the enamel. Nanoindentation techniques were used to map profiles of elastic modulus and hardness across tooth sections from the enamel-dentin junction to the outer enamel surface in a broad sample of primates including apes, Old World monkeys, New World monkeys, and lemurs. The measured data profiles feature considerable overlap among species, indicating a high degree of commonality in mechanical properties. These results suggest that differences in the load-bearing capacity of primate molar teeth are more a function of morphology-particularly tooth size and enamel thickness-than of underlying mechanical properties. 相似文献
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Non-unions pose complications in fracture management that can be treated using electrical stimulation (ES). Bone marrow mesenchymal stem cells (BMMSCs) are essential in fracture healing; however, the effect of different clinical ES waveforms on BMMSCs cellular activities remains unknown. We compared the effects of direct current (DC), capacitive coupling (CC), pulsed electromagnetic field (PEMF) and degenerate wave (DW) on cellular activities including cytotoxicity, proliferation, cell-kinetics and apoptosis by stimulating human-BMMSCs 3 hours a day, up to 5 days. In addition, migration and invasion were assessed using fluorescence microscopy and by quantifying gene and protein expression. We found that DW had the greatest proliferative and least apoptotic and cytotoxic effects compared to other waveforms. DC, DW and CC stimulations resulted in a higher number of cells in S phase and G(2)/M phase as shown by cell cycle analysis. CC and DW caused more cells to invade collagen and showed increased MMP-2 and MT1-MMP expression. DC increased cellular migration in a scratch-wound assay and all ES waveforms enhanced expression of migratory genes with DC having the greatest effect. All ES treated cells showed similar progenitor potential as determined by MSC differentiation assay. All above findings were shown to be statistically significant (p<0.05). We conclude that ES can influence BMMSCs activities, especially DW and CC, which show greater invasion and higher cell proliferation compared to other types of ES. Application of DW or CC to the fracture site may help in the recruitment of BMMSCs to the wound that may enhance rate of bone healing at the fracture site. 相似文献
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Abadi AT Taghvaei T Mobarez AM Carpenter BM Merrell DS 《Journal of microbiology (Seoul, Korea)》2011,49(6):987-993
The purpose of this study was to evaluate the primary resistance rates of recent clinical Helicobacter pylori isolates to the most commonly used antibiotics in Iran. Two hundreds and ten patients presenting with gastric maladies between
January and July of 2009 were enrolled in this study. Endoscopy was performed, and biopsy specimens were collected from each
patient for subsequent bacterial culture of H. pylori. Single colony isolates from each patient were then used for antimicrobial susceptibility testing. The disk diffusion method
was used to determine susceptibility patterns. One hundred and ninety-seven of the patients were H. pylori positive (93.8%). The rates of resistance to tetracycline, amoxicillin, ciprofloxacin, metronidazole, clarithromycin, and
furizoladone were 37.1%, 23.9%, 34.5%, 65.5%, 45.2%, and 61.4%, respectively. A significant association between amoxicillin
resistance and disease state (P<0.05) was identified. Furthermore, some double, triple, quadruple, and quintuple combinations of antibiotic resistance were
found to be associated with disease state. This study evaluated the prevalence of H. pylori resistance to the most commonly prescribed antibiotics used in Iran and showed that resistance rates were generally higher
than previously reported. This data adds to the growing body of evidence that suggests there is increasing antibiotic resistance
among H. pylori isolates, which likely is responsible for the decreasing efficacy of anti-H. pylori therapy at the local and global level. Hence, there is a need for continued monitoring of resistance patterns, especially
at the local level, and for incorporation of that information into treatment regimens for H. pylori infections. 相似文献
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To assess the molecular characterization of disseminated vancomycin-resistant enterococci (VRE) in the intensive care units, 546 enterococci isolates were collected from different clinical samples in a prospective observational study. The results showed that a total number of 33 isolates (6 %) were resistant to vancomycin. Most of the VRE isolates 11 (34 %) were isolated from intensive care units (ICUs). 18 (55 %) VRE isolates were obtained from urinary tract infections. The results from pulsed-field gel electrophoresis showed five common types (CT) and 13 single types (ST) among the VRE isolates. The analysis showed two and one major CTs and ST among the ICUs isolates, respectively. Tn1546 transposon was analyzed using ClaI-digested long PCR (L-PCR) RFLP followed by sequencing. The results showed the presence of two different lineages of transposon among the two clonal groups. Lineage 1 with the arrangement of Tn1546 prototype in the first clonal group and the second lineage with 13 kb harboring two insertion sequences, IS1216 V and IS1542. DNA hybridization showed that vanA gene in all VRE isolates, with an exception of one isolate, was present in the same location on the genome. Overall, the results suggest that a few VRE clonal types were disseminated in ICUs in hospitals in Iran which were able to transfer their vanA with high conjugation frequency. 相似文献
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