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991.
992.
The aim of this study was to determine the impact of increased copper contents on selected physiological processes in oneyear-old Pinus sylvestris L. needles from a former German timber storage area in Warcino Forest District, a subject to an environmental quality survey. Samples were collected from the area with the high copper content in the soil. The control area was a nearby pine tree stand showing unimpeded growth. The significant growth inhibition was found in dwarf shoots and whole needles, increased water content, and reduced dry mass were also observed. The chlorophyll content was lowered, while 20% higher electrolyte leakage was found. Chlorophyll a fluorescence indicated only higher values of the nonphotochemical quenching in P. sylvestris from the Cu-site. Significant differences were shown in the rate of gas exchange measured by changes in carbon dioxide or oxygen concentration. The intensity of photosynthesis in needles of P. sylvestris from the Cu-site measured by CO2 uptake was considerably higher than that of oxygen production. The rate of respiration in the needles from the Cu-site measured by the amount of released CO2 was higher only by 15%, while according to O2 consumed, the rate increased by 30% in relation to the control. Our results suggest that the copper accumulation in P. sylvestris needles affected the morphology and physiology of the studied organs.  相似文献   
993.
Mammary gland development is critically dependent on the interactions between its stromal and epithelial compartments. In this study, we established a co-culture of bovine mammary epithelial Mac-T cells and murine preadipocyte 3T3-L1 cells. Mac-T cells were co-cultured with 3T3-L1 cells for four days and production of milk proteins was induced for three days. After seven days of co-culturing, the number of alveolar-like colonies in the presence of 3T3-L1 cells was significantly higher than that in control group. Expression levels of αS1-casein and β-casein mRNAs were significantlyincreased by co-culturing with 3T3-L1 cells. In addition, casein protein production was significantly higher in the co-culture of Mac-T cells with 3T3-L1 cells than in control Mac-T cells. Substances that induced casein production in Mac-T cells also stimulated adipogenesis in 3T3-L1 cells. We suggest that a co-culture system of bovine mammary epithelial cells and preadipocyte cells is an efficient method for in vitro milk protein production.  相似文献   
994.
Migrating long distances requires time and energy, and may interact with an individual's performance during breeding. These seasonal interactions in migratory animals are best described in populations with disjunct nonbreeding distributions. The black‐tailed godwit (Limosa limosa limosa), which breeds in agricultural grasslands in Western Europe, has such a disjunct nonbreeding distribution: The majority spend the nonbreeding season in West Africa, while a growing number winters north of the Sahara on the Iberian Peninsula. To test whether crossing the Sahara has an effect on breeding season phenology and reproductive parameters, we examined differences in the timing of arrival, breeding habitat quality, lay date, egg volume, and daily nest survival among godwits (154 females and 157 males), individually marked in a breeding area in the Netherlands for which wintering destination was known on the basis of resightings. We also examined whether individual repeatability in arrival date differed between birds wintering north or south of the Sahara. Contrary to expectation, godwits wintering south of the Sahara arrived two days earlier and initiated their clutch six days earlier than godwits wintering north of the Sahara. Arrival date was equally repeatable for both groups, and egg volume larger in birds wintering north of the Sahara. Despite these differences, we found no association between wintering location and the quality of breeding habitat or nest survival. This suggests that the crossing of an important ecological barrier and doubling of the migration distance, twice a year, do not have clear negative reproductive consequences for some long‐distance migrants.  相似文献   
995.
Ten years have passed since the first publication announcing the generation of induced pluripotent stem cells (iPSCs). Issues related to ethics, immune rejection, and cell availability seemed to be solved following this breakthrough. The development of iPSC technology allows advances in in vitro cell differentiation for cell therapy purpose and other clinical applications. This review provides a perspective on the iPSC potential for cell therapies, particularly for hematological applications. We discuss the advances in in vitro hematopoietic differentiation, the possibilities to employ iPSC in hematology studies, and their potential clinical application in hematologic diseases. The generation of red blood cells and functional T cells and the genome editing technology applied to mutation correction are also covered. We highlight some of the requirements and obstacles to be overcome before translating these cells from research to the clinic, for instance, iPSC variability, genotoxicity, the differentiation process, and engraftment. Also, we evaluate the patent landscape and compile the clinical trials in the field of pluripotent stem cells. Currently, we know much more about iPSC than in 2006, but there are still challenges that must be solved. A greater understanding of molecular mechanisms underlying the generation of hematopoietic stem cells is necessary to produce suitable and transplantable hematopoietic stem progenitor cells from iPSC.  相似文献   
996.
In eukaryotes, mechanisms such as alternative splicing (AS) and alternative translation initiation (ATI) contribute to organismal protein diversity. Specifically, splicing factors play crucial roles in responses to environment and development cues; however, the underlying mechanisms are not well investigated in plants. Here, we report the parallel employment of short‐read RNA sequencing, single molecule long‐read sequencing and proteomic identification to unravel AS isoforms and previously unannotated proteins in response to abscisic acid (ABA) treatment. Combining the data from the two sequencing methods, approximately 83.4% of intron‐containing genes were alternatively spliced. Two AS types, which are referred to as alternative first exon (AFE) and alternative last exon (ALE), were more abundant than intron retention (IR); however, by contrast to AS events detected under normal conditions, differentially expressed AS isoforms were more likely to be translated. ABA extensively affects the AS pattern, indicated by the increasing number of non‐conventional splicing sites. This work also identified thousands of unannotated peptides and proteins by ATI based on mass spectrometry and a virtual peptide library deduced from both strands of coding regions within the Arabidopsis genome. The results enhance our understanding of AS and alternative translation mechanisms under normal conditions, and in response to ABA treatment.  相似文献   
997.
PURPOSE: To assess the effect of adding neoadjuvant chemotherapy (NACT) to concurrent chemoradiotherapy (CCRT) in patients with locoregionally advanced nasopharyngeal carcinoma (NPC) and undetectable pretreatment Epstein-Barr virus (pEBV) DNA. MATERIALS AND METHODS: We enrolled 639 NPC patients with stage II to IVB and undetectable pEBV DNA to receive CCRT with or without NACT. Radiotherapy was 2.0 to 2.27 Gy per fraction with five daily fractions per week for 6 to 7 weeks to the primary tumor and 62 to 70 Gy to the involved neck area. NACT was cisplatin (80-100 mg/m2 day 1) and 5-fluorouracil (800-1000 mg/m2, 120-hour continuous intravenous infusion) every 3 weeks for two or three cycles. CCRT was cisplatin (80-100 mg/m2 day 1) every 3 weeks for three cycles. RESULTS: For all patients, the 5-year overall survival (OS), locoregional relapse-free survival (LRFS), distant metastasis-free survival (DMFS), and progression-free survival (PFS) rates were 91.9%, 92.2%, 95.0%, and 86.4%, respectively. There was no significant difference in OS (5-year OS 90.8% [NACT + CCRT group] vs 92.7% [CCRT alone]; hazard ratio [HR] 1.24; P = .486), LRFS (HR 1.13, 95% confidence interval [CI] 0.59-2.14, P = .715), DMFS (HR 0.78, 95% CI 0.34-1.78, P = .554), or PFS (HR 1.21, 95% CI 0.75-1.95, P = .472). CONCLUSION: CCRT with or without NACT produced a good treatment outcome in patients with locoregionally advanced NPC and undetectable pEBV DNA, but NACT before CCRT did not significantly improve survival rates.  相似文献   
998.
999.
Leukocyte differentiation antigens (LDAs) play important roles in the immune system, by serving as surface markers and participating in multiple biological activities, such as recognizing pathogens, mediating membrane signals, interacting with other cells or systems, and regulating cell differentiation and activation. Data mining is a powerful tool used to identify novel LDAs from whole genome. LRRC25 (leucine rich repeat-containing 25) was predicted to have a role in the function of myeloid cells by a large-scale “omics” data analysis. Further experimental validation showed that LRRC25 is highly expressed in primary myeloid cells, such as granulocytes and monocytes, and lowly/intermediately expressed in B cells, but not in T cells and almost all NK cells. It was down-regulated in multiple acute myeloid leukemia (AML) cell lines and bone marrow cells of AML patients and up-regulated after all-trans retinoic acid (ATRA)-mediated granulocytic differentiation in AML cell lines and acute promyelocytic leukemia (APL; AML-M3, FAB classification) cells. Localization analysis showed that LRRC25 is a type I transmembrane molecule. Although ectopic LRRC25 did not promote spontaneous differentiation of NB4 cells, knockdown of LRRC25 by siRNA or shRNA and knockout of LRRC25 by the CRISPR-Cas9 system attenuated ATRA-induced terminal granulocytic differentiation, and restoration of LRRC25 in knockout cells could rescue ATRA-induced granulocytic differentiation. Therefore, LRRC25, a potential leukocyte differentiation antigen, is a key regulator of ATRA-induced granulocytic differentiation.  相似文献   
1000.
Negative phototropism of rice root and its influencing factors   总被引:8,自引:0,他引:8  
Some characteristics of the rice (Oryza sativa L.) root were found in the experiment of unilaterally irradiating the roots which were planted in water: (i) All the seminal roots, adventitious roots and their branched roots bent away from light, and their curvatures ranged from 25℃ to 60℃. The curvature of adventitious root of the higher node was often larger than that of the lower node, and even larger than that of the seminal root. (ii) The negative phototropic bending of the rice root was mainly due to the larger growth increment of root-tip cells of the irradiated side compared with that of the shaded side, (iii) Root cap was the site of light perception. If root cap was shaded while the root was irradiated the root showed no negative phototropism, and the root lost the characteristic of negative phototropism when root cap was divested. Rice root could resume the characteristic of negative phototropism when the new root cap grew up, if the original cells of root cap were well protected while root ca  相似文献   
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