CX3CL1 (fractalkine), the sole member of chemokine CX3C family, is implicated in inflammatory and neuropathic pain via activating its receptor CX3CR1 on neural cells in spinal cord. However, it has not been fully elucidated whether CX3CL1 or CX3CR1 contributes to the development of morphine tolerance. In this study, we found that chronic morphine exposure did not alter the expressions of CX3CL1 and CX3CR1 in spinal cord. And neither exogenous CX3CL1 nor CX3CR1 inhibitor could affect the development of morphine tolerance. The cellular localizations of spinal CX3CL1 and CX3CR1 changed from neuron and microglia, respectively, to all the neural cells during the development of morphine tolerance. A microarray profiling revealed that 15 members of chemokine family excluding CX3CL1 and CX3CR1 were up-regulated in morphine-treated rats. Our study provides evidence that spinal CX3CL1 and CX3CR1 may not be involved in the development of morphine tolerance directly.
Mechanisms and occurrence of macrolide resistance in the periodontal pathogen Treponema denticola have received little attention. In this study, erythromycin resistance due to mutations in the genes encoding T. denticola 23S rRNA was investigated. The T. denticola genome was shown to contain two copies of 23S rDNA. 23S rRNA genes of nine erythromycin-resistant isolates derived from T. denticola were amplified and sequences were analyzed. All the erythromycin-resistant strains had at least one A-->G transition mutation at the 23S rRNA gene sequence cognate to position A2058 in Escherichia coli 23S rDNA. This suggests that antibiotic pressure is sufficient to select for point mutations that confer resistance in this organism. 相似文献
Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus (HaSNPV) has been developed as a commercial biopesticide to control the cotton bollworm, H. armigera, in China. The major limitation to a broader application of this virus has been the relative long time to incapacitate the target insect. Two HaSNPV recombinants with improved insecticidal properties were released in bollworm-infested cotton. One recombinant (HaCXW1) lacked the ecdysteroid UDP-glucosyltransferase (egt) gene and in another recombinant (HaCXW2), an insect-selective scorpion toxin (AaIT) gene replaced the egt gene. In a cotton field situation H. armigera larvae treated with either HaCXW1 or HaCXW2 were killed faster than larvae in HaSNPV-wt treated plots. Second instar H. armigera larvae, which were collected from HaCXW1 and HaCXW2 treated plots and further reared on artificial diet, showed reduced ST(50) values of 15.3 and 26.3%, respectively, as compared to larvae collected from HaSNPV-wt treated plots. The reduction in consumed leaf area of field collected larvae infected with HaCXW1 and HaCXW2 was approximated 50 and 63%, respectively, as compared to HaSNPV-wt infected larvae at 108 h after treatment. These results suggest that in a cotton field situation the recombinants will be more effective control agents of the cotton bollworm than wild-type HaSNPV. 相似文献
The effect of electroacupuncture (EA) on the reflex cardiovascular response induced by mechanical distension of the stomach was studied in ventilated male Sprague-Dawley rats anesthetized by ketamine and alpha-chloralose. Repeated balloon inflation of the stomach to produce 20 mmHg tension on the gastric wall induced a consistent rise in mean arterial pressure, while heart rate (372 +/- 22 beats/min) was unchanged. This response was reversed by transection of the splanchnic nerves. Bilateral application of EA (1-2 mA, 2 Hz) at Neiguan-Jianshi acupoints (pericardial meridian, Pe 5-6) over the median nerve for 30 min significantly decreased the pressor response from 33 +/- 6 to 18 +/- 4 mmHg (n = 7, P < 0.05). This effect began after 10 min of EA and continued for 40 min after termination of EA. EA at Zusanli-Shangquxu acupoints (stomach meridian, St 36-37) over the deep peroneal nerve similarly inhibited the pressor response. The effect lasted for 10 min after EA was stopped (n = 6, P < 0.05), while EA at Guangming-Xuanzhong acupoints (gallbladder meridian, GB 37-39) over the superficial peroneal nerve did not inhibit the pressor response. Naloxone injected intravenously (n = 6) immediately after termination of EA or administered by microinjection into the rostral ventrolateral medulla (rVLM) 25 min after initiation of EA (n = 6) reversed the inhibition by EA, suggesting an opiate mechanism, including the rVLM, was involved. 相似文献
Recently, induced pluripotent stem cells (iPS cells) have been derived from various techniques and show great potential for therapy of human diseases. Furthermore, the iPS technique can be used to provide cell models to explore pathological mechanisms of many human diseases in vitro, such as Duchenne muscular dystrophy (DMD), which is a severe recessive X-linked form of muscular dystrophy without effective treatment. In this study, we try to determine whether there are different characteristics of myocytes from mdx iPS cells and C57BL/10 iPS cells. Our results showed that both of mdx and C57BL/10 cells could be induced into iPS cells in vitro, whereas colony-forming ability of mdx iPS cells was much weaker than that of C57BL/10 iPS cells. Meanwhile, mdx iPS cells could be induced to differentiate into myocytes, whereas their differentiation efficiency was much lower than that of C57BL/10 iPS cells. And, the number of apoptotic cells in differentiated myocytes from mdx iPS cells was significantly higher than that from C57BL/10 iPS cells. More importantly, treatment of a pan-caspase inhibitor (Z-VAD) produced a significant decrease in apoptotic cells. This study might add some insight to the biology study of dystrophin gene. 相似文献
The purpose of this study was to investigate the effect of bufalin on the anti-proliferative activity of sorafenib in the
human hepatocellular carcinoma (HCC) cell lines PLC/PRF/5 and Hep G-2 and to determine the relevant molecular mechanism. Concurrent
treatment with sorafenib and bufalin at a fixed ratio (25:1) for 48 h resulted in synergistic growth inhibition in HCC cell
lines as determined by CCK-8 cell viability assays. Exposure of both PLC/PRF/5 and Hep G-2 cells to this combination of sorafenib
(6.25 μM) and bufalin (50 nM) resulted in noticeable increases in apoptotic cell death, as evidenced by the disruption of
mitochondria, compared to treatment with either agent alone. Although both sorafenib (6.25 μM) and bufalin (250 nM) alone
inhibited the phosphorylation of ERK, the reduction in pERK was more pronounced in the cells treated with a combination of
bufalin (50 nM) and sorafenib (250 nM). Furthermore, the inhibitory effect of bufalin on pERK was blocked by the PI3kinase
inhibitor LY294002, suggesting that the reduction in pERK induced by bufalin might be mediated by AKT in these two HCC cell
lines. Taken together, the results of our study suggest that bufalin enhances the anti-cancer effects of sorafenib on PLC/PRF/5
and Hep G-2 by contributing to the downregulation of ERK. 相似文献
Sex ratio theory is one of the most productive fields in research on evolutionary biology. Pollinating fig wasps, due to their particular natural life history, are considered to be a valuable model for the study of sex ratio evolution. A great deal of research concerning the factors that affect pollinator fig wasp (Agaonidae) progeny sex ratio has been done, and at present three main factors (haplodiploidy, local mate competition and inbreeding) are found to be important at the population level. However, there still exists variation between empirical data and model predictions. Another factor to which little thought has been given before is the effect of non-pollinating fig wasps (NPFWs) which parasitize in the larvae gall of pollinator thus kill pollinators and exploit the fig/fig pollinator mutualistic systems. In this study, we focus on why and how non-pollinating fig wasps distort pollinator fig wasp’s original sex ratio. Through controlling the number of ovipositing foundresses inside a fig, combined with the observation of ovipositing behavior and sequence, we studied three species of wasp in the figs of a dioecious fig Ficus semicordata including the pollinator Ceratosolen gravely and NPFWs Platyneura cunia, Sycoscapter trifemmensis in tropical area of Xishuangbanna from September to December 2009. First, we observed the timing of oviposition of all fig wasps utilizing F. semicordata and found differences when compared to previous studies. Such as P. cunia is the fourth rather then the secondary fig wasps to oviposit on the syconia approximately 10 days after the pollinator. S. trifemmensis oviposits much earlier than previously thought, 14–32 days after the pollinators. We examined the spatial location of male and female progeny of the pollinator. We found foundresses of pollinator prefer to use innermost ovules first. Only at high offspring numbers were the outer ovules used. More male pollinator offspring were developed near the fig cavity, while female pollinator offspring were more evenly distributed among ovule layers. As pollinator offspring numbers increased, this phenomenon became more pronounced. This pattern of segregation of male larvae gall in inner ovules and female larvae gall in outer ovules suggests that female offspring might be more vulnerable to attack by parasitic wasps that oviposit from outside the syconium. Experiments later demonstrated that NPFWs are restricted by their ovipositor length and they prefer to or can only lay their eggs into ovules near the fig wall. Then we examined the spatial location of NPFWs and compared this with the spatial location of male/female progeny of pollinator. NPFWs had a high probability of parasitizing female pollinator larvae. Thus, NPFWs have a substantial effect on the sex ratio of the pollinator, as parasitism risk decreases towards the center of the syconium, where inner ovules provide enemy-free space for most of male pollinator offspring. Partial correlation analyse shows that sex ratio of pollinator progeny has a positive relationship with the number of NPFWs. We suggest that the resulting gradient in offspring viability between male and female contributes to selection on pollinators’ for a less femalebiased sex ratio. When the affect of NPFWs was excluded, the pollinator sex ratio was not in good agreement with local mate competition theory, although it was still female-biased. In addition, the average number of offspring per foundress decreased with increasing foundress number, but pollinator sex ratio was positively related to brood size. Thus, pollinator females do not appear to adjust their sex ratio to foundress density directly, but use brood size and foundress density simultaneously as cues to assess potential LMC. 相似文献