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21.
Fusarium oxysporum is one of the most abundant and diverse fungal species found in soils and includes nonpathogenic, endophytic, and pathogenic strains affecting a broad range of plant and animal hosts. Conidiation is the major mode of reproduction in many filamentous fungi, but the regulation of this process is largely unknown. Lysine acetylation (Kac) is an evolutionarily conserved and widespread posttranslational modification implicated in regulation of multiple metabolic processes. A total of 62 upregulated and 49 downregulated Kac proteins were identified in sporulating mycelia versus nonsporulating mycelia of F. oxysporum. Diverse cellular proteins, including glycolytic enzymes, ribosomal proteins, and endoplasmic reticulum–resident molecular chaperones, were differentially acetylated in the sporulation process. Altered Kac levels of three endoplasmic reticulum–resident molecular chaperones, PDIK70, HSP70K604, and HSP40K32 were identified that with important roles in F. oxysporum conidiation. Specifically, K70 acetylation (K70ac) was found to be crucial for maintaining stability and activity of protein disulphide isomerase and the K604ac of HSP70 and K32ac of HSP40 suppressed the detoxification ability of these heat shock proteins, resulting in higher levels of protein aggregation. During conidial formation, an increased level of PDIK70ac and decreased levels of HSP70K604ac and HSP40K32ac contributed to the proper processing of unfolded proteins and eliminated protein aggregation, which is beneficial for dramatic cell biological remodeling during conidiation in F. oxysporum.  相似文献   
22.
Birds encounter climate at the scale of microclimates that can vary rapidly in time and space and so understanding potential vulnerability and adaptations to those microclimates requires fine‐scale measurements that accurately track thermal exposures. However, few options exist for recording the microclimates actually experienced by birds (realized microclimates). We constructed and tested a simple, low‐cost, temperature logger for recording the realized microclimates of ground‐nesting birds. We developed attachment protocols for band‐mounting Thermochron iButtons on Ring‐billed Gull (Larus delawarensis) chicks. We tested these mounted, temperature‐logging devices on 20 chicks weighing > 200 g (device weight was 4 g), attaching devices for 48 h and observing behavior before and after attachment and removal. Devices recorded temperature immediately surrounding the leg at 2‐min intervals. Recorded temperatures were strong predictors of observed thermoregulatory behaviors (panting and sitting), outperforming predictions based on air temperatures measured by basic, static approaches. Through comparison with matched controls (chicks with just a band), we detected no adverse physiological effects of devices, no effects on social or feeding behavior, and only a short‐term decrease in inactivity immediately after device attachment (likely due to increased preening). By attaching iButtons to the legs of birds, we quantified realized thermal exposure, integrating air temperature, modes of environmental heat transfer, and bird behavior at microclimatic scales. Although not yet validated for broader use, our approach (including possible miniaturization) should be suitable to measure thermal exposure of adults, not just chicks, allowing collection of data concerning thermal exposures during flight under field conditions. At ~ $25 USD per device, our approach facilitates experimental protocols with robust sample sizes, even for relatively modest budgets.  相似文献   
23.

1. 1. Spectral integral reflectance, transmittance and the resulting absorption of intact and descaled butterfly wings of the black-winged Pachliopta aristolochiae (Papilionidae), the white-winged Pieris brassicae (Pieridae), and the yellow-winged Gonepteryx rhamni (Pieridae) were determined between 350 and 800 nm.

2. 2. Whereas in the black forewing of the dorsal basking Pachliopta almost all incident light is absorbed nearly independent of the wavelength and thus converted into heat, the white forewing of the body basking Pieris absorbs less than 20% in the visible range of the spectrum.

3. 3. The yellow hindwing of the lateral basking Gonepteryx absorbs to a higher degree than the Pierid wing, but—due to the sparsely arranged scales—transmittance is clearly increased (40–50% between 525 and 800 nm).

4. 4. The varying thermal characteristics of the different wings with reference to the color and arrangement of the scales and the different basking strategies of the butterflies are discussed.

Author Keywords: Behavioral thermoregulation; coloration; butterfly wing; radiation absorption; heat gain; sun basking  相似文献   

24.
蓝绿空间作为城市绿色基础设施的重要组成部分,对促进城市热环境健康、改善局地微气候具有重要作用。利用Landsat 8遥感影像、土地利用等数据,基于辐射传输方程算法、K均值聚类算法、相关性分析等方法,量化了典型的高密度中心城区--北京五环快速路以内地区的1199块1hm2以上的蓝绿空间冷岛效应的表征指标,并分析与蓝绿空间规模、形状复杂度、景观组成、环境组成、植被覆盖等要素的相关关系,还根据蓝绿空间的不同降温特性进行分类,探讨每类蓝绿空间在缓解高密度中心城区热岛效应中的独特作用、优势与机制。结果表明:(1)蓝绿空间的规模、形状复杂度、景观组成等景观要素与冷岛效应的关系显著,如总面积、绿地面积和水体面积与降温幅度、降温范围、降温服务呈显著正相关,与降温效率和降温速率呈显著负相关;周长与降温范围、降温服务呈显著正相关,与降温效率和速率呈显著负相关;周长面积比与降温幅度和降温服务呈显著负相关,与降温效率和蓝绿空间自身温度呈显著正相关,而形状指数则与降温范围和降温服务呈显著正相关。(2)蓝绿空间的环境要素与冷岛效应也存在相关关系。蓝绿空间之间会产生冷岛效应的协同与促进现象,蓝绿空间降温范围内的其他蓝绿空间的总面积与该蓝绿空间的降温幅度、降温范围、降温服务和辐射距离呈显著正相关,与蓝绿空间自身温度呈显著负相关。(3)蓝绿空间的总面积、水体面积、周长与降温幅度之间,周长面积比与降温效率之间存在阈值,为节约土地资源、保证降温效果,建议不应过多超过阈值。(4)基于蓝绿空间在降温幅度、效率、辐射距离等方面的差异,将蓝绿空间划分为4类。高密度中心城区蓝绿空间规划建设应充分评估区域降温需求,了解蓝绿空间降温现状,合理配置具有不同降温特性和优势的蓝绿空间,在土地和资金有限的情况下,充分发挥各类蓝绿空间的冷岛效应。本研究有助于政府和规划师摸清当前蓝绿空间冷岛效应的现状、问题和发展潜力,对理论和实践具有一定参考意义。  相似文献   
25.
Alkaptonuria (AKU) is a disease caused by a deficient homogentisate 1,2-dioxygenase activity leading to systemic accumulation of homogentisic acid (HGA), that forms a melanin-like polymer that progressively deposits onto connective tissues causing a pigmentation called “ochronosis” and tissue degeneration. The effects of AKU and ochronotic pigment on the biomechanical properties of articular cartilage need further investigation. To this aim, AKU cartilage was studied using thermal (thermogravimetry and differential scanning calorimetry) and rheological analysis. We found that AKU cartilage had a doubled mesopore radius compared to healthy cartilage. Since the mesoporous structure is the main responsible for maintaining a correct hydrostatic pressure and tissue homoeostasis, drastic changes of thermal and rheological parameters were found in AKU. In particular, AKU tissue lost its capability to enhance chondrocytes metabolism (decreased heat capacity) and hence the production of proteoglycans. A drastic increase in stiffness and decrease in dissipative and lubricant role ensued in AKU cartilage. Multiphoton and scanning electron microscopies revealed destruction of cell–matrix microstructure and disruption of the superficial layer. Such observations on AKU specimens were confirmed in HGA-treated healthy cartilage, indicating that HGA is the toxic responsible of morphological and mechanical alterations of cartilage in AKU.  相似文献   
26.
Fisher information for a multivariate extreme value distribution   总被引:7,自引:0,他引:7  
SHI  DAOJI 《Biometrika》1995,82(3):644-649
Explicit algebraic formulae for the Fisher information matrixof the multivariate extreme value distribution with generalisedextreme value margins and logistic dependence structure aregiven.  相似文献   
27.
Abstract. A method for modelling heat and mass transfer by diffusion-controlled electrode reactions in a fluid tunnel is described. In this procedure, a nickelplated leaf functions as a test electrode, and the convective transfer of ions to the leaf cathode in an electrolyte-filled flow tunnel is measured as a function of flow rate. The method permits the simulation of water vapour and heat transfer, and in particular, the determination of boundary layer conductances, by analogy with observed ion transfer. The approach is applicable to many problems in modelling heat and mass transfer between leaves and their surroundings, and is especially useful in examining the properties of leaves in which surface characteristics or overall shape are complex. Using this method, the properties of the highly dissected leaves of Achillea lanulosa with regard to forced convection were investigated. The leaves showed high transfer conductances, indicating that the effective unit of heat transfer was probably the individual leaf subelements. Conductances tended to be greater and effective characteristic dimensions smaller for the larger, more open leaves of a lower altitude population in contrast with leaves from high altitude plants. While the results provide insight into the properties of these complex leaf shapes, difficulties in interpreting the findings are discussed, and a number of exploratory approaches are suggested for data analysis and interpretation.  相似文献   
28.

1. 1.Increased heat tolerance in FHM-cells from Pimephales promelas (Pisces) can be induced by culturing the cells at elevated temperatures (heat resistant acclimation) as well as by heat shock (heat hardening).

2. 2.After shift of culturing temperature (CT) from 16 to 32°C both effects are detectable with different temporal patterns.

3. 3.Cellular concentrations of heat-shock proteins correlate with the hardening effect but not with heat resistance acclimation.

4. 4.Several culturing temperature specific proteins were detected. The patterns of some enzymes are also altered by culturing temperature.

5. 5.Heat resistance acclimation is not caused by selection of a thermoresistant subpopulation of cells.

6. 6.Heat hardening and heat resistance acclimation must be distinguished as different phenomena in FHM-cells.

Author Keywords: Culturing temperature specific proteins; esterase isoenzymes; FHM-cells; heat hardening; heat-shock proteins; heat resistance acclimation; thermotolerance  相似文献   

29.

1. 1.Cueta trivirgata larvae construct pits in the dry Kuiseb River bed in the Namib Desert.

2. 2.An art, Ocymyrmex robustior comprises 65.4% of the biomass of prey consumed by the ant-lions.

3. 3.O. robustior is active between surface temperatures of 27–68°C.

4. 4.Ant-lions tolerate high body temperatures (LD50 = 53.4°C).

5. 5.By exploiting the pit microclimate and by digging below the surface during extreme thermal loads, ant-lions can capture prey at surface temperatures of 13–63°C.

6. 6.These behavioural and physiological adaptations enable ant-lions to maximize the duration of vigilance and hence prey capture success.

Author Keywords: Neuroptera; Myrmeleontidae; Cueta trivirgata; ants; Ocymyrmex robustior; micro-climate; diet; behaviour; heat torpor; Namib Desert  相似文献   

30.
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