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281.
Figs and fig pollinators are one of the few classic textbook examples of obligate pollination mutualism. The specific dependence of fig pollinators on the relatively safe living environment with sufficient food sources in the enclosed fig syconia implies that they are vulnerable to habitat changes. However, there is still no extensive genomic evidence to reveal the evolutionary footprint of this long-term mutually beneficial symbiosis in fig pollinators. In fig syconia, there are also non-pollinator species. The non-pollinator species differ in their evolutionary and life histories from pollinators. We conducted comparative analyses on 11 newly sequenced fig wasp genomes and one previously published genome. The pollinators colonized the figs approximately 66.9 million years ago, consistent with the origin of host figs. Compared with nonpollinators, many more genes in pollinators were subject to relaxed selection. Seven genes were absent in pollinators in response to environmental stress and immune activation. Pollinators had more streamlined gene repertoires in the innate immune system, chemosensory toolbox, and detoxification system. Our results provide genomic evidence for the differentiation between pollinators and nonpollinators. The data suggest that owing to the long-term adaptation to the fig, some genes related to functions no longer required are absent in pollinators.  相似文献   
282.
Moderately to well-preserved radiolarians have been extracted from nine greyish green and purplish-red bedded cherts in the mud-matrix mélange of the eastern Yarlung-Zangbo Suture Zone (YZSZ) at Jinlang Section, Zedong, southern Xizang (Tibet). Forty-two species belonging to 27 genera, including Middle Jurassic characteristic species such as Laxtorum (?) jurassicum Isozaki and Matsuda, Laxtorum (?) hichisoense Isozaki and Matsuda, Stichocapsa japonica Yao, Stichocapsa robusta Matsuoka, Parahsuum (?) magnum Takemura, Sella chrafatensis (El Kadiri), and Unuma typicus Ichikawa and Yao are recognized and three assemblages, Laxtorum (?) jurassicum Assemblage (Aalenian), Quarticella ovalis Assemblage (late Bajocian), and Stichocapsa robusta Assemblage (middle Bathonian) are established in ascending order. These assemblages can be well correlated to the Middle Jurassic Unitary Association (UA) Zones (Baumgartner et al., 1995) in west Tethys and coeval biozones in Japan and provide reliable age information for the Middle Jurassic stratigraphic correlation of the pelagic sediments along the YZSZ.  相似文献   
283.
The earliest models for how morphogen gradients guide embryonic patterning failed to account for experimental observations of temporal refinement in gene expression domains. Following theoretical and experimental work in this area, dynamic positional information has emerged as a conceptual framework to discuss how cells process spatiotemporal inputs into downstream patterns. Here, we show that diffusion determines the mathematical means by which bistable gene expression boundaries shift over time, and therefore how cells interpret positional information conferred from morphogen concentration. First, we introduce a metric for assessing reproducibility in boundary placement or precision in systems where gene products do not diffuse, but where morphogen concentrations are permitted to change in time. We show that the dynamics of the gradient affect the sensitivity of the final pattern to variation in initial conditions, with slower gradients reducing the sensitivity. Second, we allow gene products to diffuse and consider gene expression boundaries as propagating wavefronts with velocity modulated by local morphogen concentration. We harness this perspective to approximate a PDE model as an ODE that captures the position of the boundary in time, and demonstrate the approach with a preexisting model for Hunchback patterning in fruit fly embryos. We then propose a design that employs antiparallel morphogen gradients to achieve accurate boundary placement that is robust to scaling. Throughout our work we draw attention to tradeoffs among initial conditions, boundary positioning, and the relative timescales of network and gradient evolution. We conclude by suggesting that mathematical theory should serve to clarify not just our quantitative, but also our intuitive understanding of patterning processes.  相似文献   
284.
Prostate cancer is a major health concern in males worldwide, owing to its high incidence. Sparstolonin B (SsnB), a component of the Chinese herbal medicine Sparganium stoloniferum, is used to treat many diseases. However, the effects and mechanisms of action of SsnB in prostate cancer have not yet been reported. In this study, we evaluated the effects of SsnB on cellular processes and tumour growth. In particular, we verified that SsnB could inhibit the proliferation, migration and invasion of prostate cancer cells and induce apoptosis by activating G2/M phase arrest in vitro based on a series of cytological experiments. In vivo, we found that SsnB could inhibit tumour growth in nude mouse xenograft models. We further confirmed that SsnB could repress the PI3K/AKT pathway by increasing reactive oxygen species (ROS) accumulation and oxidative stress. Collectively, SsnB inhibits tumour growth and induces apoptosis in prostate cancer via the suppression of the ROS-mediated PI3K/AKT pathway and may be a new alternative to adjuvant therapy for prostate cancer.  相似文献   
285.
International Journal of Peptide Research and Therapeutics - The peptides YYGGEGSSSEQG and SESEM derived from rice α-globulin have been reported to possess anti-atherosclerotic activity, but...  相似文献   
286.
The ADP-ribosylation factor-like proteins (ARLs) have been proved to regulate the malignant phenotypes of several cancers. However, the exact role of ARLs in gastric cancer (GC) remains elusive. In this study, we systematically investigate the expression status, interactive relations, potential pathways, genetic variations and clinical values of ARLs in GC. We find that ARLs are significantly dysregulated in GC and involved in various cancer-related pathways. Subsequently, machine learning models identify ARL4C as one of the two most significant clinical indicators among ARLs for GC. Furthermore, ARL4C silencing remarkably inhibits the growth and metastasis of GC cells both in vitro and in vivo. Moreover, enrichment analysis indicates that ARL4C is highly correlated with TGF-β1 signalling. Correspondingly, TGF-β1 treatment dramatically increases ARL4C expression and ARL4C knockdown inhibits the phosphorylation level of Smads, downstream factors of TGF-β1. Meanwhile, the coexpression of ARL4C and TGF-β1 worsens the prognosis of GC patients. Our work comprehensively demonstrates the crucial role of ARLs in the carcinogenesis of GC and the specific mechanisms underlying the GC-promoting effects of TGF-β1. More importantly, we uncover the great promise of ARL4C-targeted therapy in improving the efficacy of TGF-β1 inhibitors for GC patients.  相似文献   
287.
A novel pH-activatable fluorescent probe, 1-(propan-2-yl)-9H-pyrido[3,4-b]indole-3-carboxylic acid ( L-1 ), based on β-carboline derivatives, has been developed, which displays significant fluorescent response toward pH variation with high selectivity, good photo-stability and favorable pKa value. Moreover, L-1 can dynamically monitor the release of protons during ester hydrolysis reaction in consistent with enzymatic kinetics manner.  相似文献   
288.
289.
Wang  Xuemei  Yan  Bangguo  Shi  Liangtao  Liu  Gangcai 《Plant Ecology》2021,222(11):1209-1224

Plant–soil feedback has been widely studied and may be particularly important in resource-poor areas. However, the roles of direct and indirect biotic effect in affecting plant growth and functional traits in this process still remained unclear. The aim of this study was to explore the roles of soil biota in affecting plant performance and traits by conducting a two-phase feedback experiment in a dry-hot valley, with a conditioning phase during which there were Dodonaea viscosa or no D. viscosa growing in the soil and a feedback phase in which the effect of the conditioned soil biota on D. viscosa performance was measured. Soil N was reduced by the presence of D. viscosa during the conditioning phase. However, D. viscosa showed a positive plant–soil feedback. In the feedback phase, the D. viscosa-conditioned soil increased the stem diameter, total biomass, and leaf dry mass content of D. viscosa, while the specific leaf area was significantly lower in D. viscosa-conditioned soil than that in bare soil. In contrast, soil sterilization had a negative effect on the growth of D. viscosa, with a significant reduction in biomass, especially in D. viscosa-conditioned soil, and soil sterilization significantly increased the root:shoot biomass ratio and litter mass. Furthermore, we showed that although the biota-driven changes in enzyme activities correlated with leaf N and especially P amount, the enzyme activity was not the main reason to promote D. viscosa growth in conditioned soil. These results suggest that the positive biotic feedback effect was superior to the negative nutrient-depleted effect on D. viscosa growth, and the direct biotic feedback effect would drive the positive effect of soil biota to a greater extent than the indirect effect. The positive biotic plant–soil feedback in dry-hot valley plays an important role in ecosystem restoration and helps in understanding plant adaptation to the local environment in this area.

  相似文献   
290.
Zhu  Yijing  Li  Qi  Yu  Hong  Liu  Shikai  Kong  Lingfeng 《Marine biotechnology (New York, N.Y.)》2021,23(5):777-789
Marine Biotechnology - The widely recognized color polymorphisms of molluscan shell have been appreciated for hundreds of years by collectors and scientists, while molecular mechanisms underlying...  相似文献   
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