Inter- and intra-specific variation in the facial colours of <Emphasis Type="Italic">Perisesarma eumolpe</Emphasis> and <Emphasis Type="Italic">Perisesarma indiarum</Emphasis> (Crustacea: Brachyura: Sesarmidae)

The colour of the characteristic facial bands in the mangrove crabs Perisesarma eumolpe (De Man) and Perisesarma indiarum (Tweedie) were investigated in relation to species, sex and size. Quantitative red/blue/green (RBG) values extracted from close-up digital photographs of 27 P. indiarum and 48 P. eumolpe specimens revealed significant differences between species and sexes. Males of both species possessed facial bands characterized by a greater intensity of blue, whereas green was more pronounced in female facial bands. It is postulated that these colour differences play a role in intra-specific sexual recognition. There existed a significant positive relationship between size and the intensity of blue in the facial bands of females of both species, suggesting these traits function as an indicator of their maturity (and possibly body condition). In large males, facial band colours contrast strongly against the surrounding mudflat and may play an important role in conspecific signalling during territorial disputes or contests over access to females. Handling editor: K. Martens     

The stimulating effects of ethylene and auxin on petiole elongation and on hyponastic curvature are independent processes in submerged Rumex palustris

The flooding-tolerant plant species Rumex palustris (Sm.) responds to complete submergence with stimulation of petiole elongation mediated by the gaseous hormone ethylene. We examined the involvement of auxin in petiole elongation. The manipulation of petiolar auxin levels by removing the leaf blade, or by addition of synthetic auxins or auxin transport inhibitors, led to the finding that auxin plays an important role in submergence-induced petiole elongation in R. palustris. A detailed kinetic analysis revealed a transient effect of removing the auxin source (leaf blade), explaining why earlier studies in which less frequent measurements were taken failed to identify any role for auxin in petiole elongation. We previously showed that the onset of stimulated petiole elongation depends on a more upright petiole angle being reached by means of hyponastic (upward) curvature, a differential growth process that is also regulated by ethylene and auxin. This raised the possibility that both ethylene and auxin stimulate elongation only indirectly by influencing hyponastic growth. We show here that the action of ethylene and auxin in promoting petiole elongation in submerged R. palustris is independent of the promoting effect that these hormones also exert on the hyponastic curvature of the same petiole.     

南方人工林叶面积指数的摄影测量

利用CI-110冠层分析仪、鱼眼镜头数码照片分析,结合胸径-叶片半表面积模型对千烟洲不同森林类型(20年生)的叶面积指数进行了测定,并对3种方法进行了比较.共调查74块样地.研究对象主要为湿地松(Pinus elliottii)林、马尾松(Pinus massoniana)林、杉木(Cunninghamia lanceolata)林.针对上述3种林型,CI-110观测值分别为1.355(0.38～2.85)、1.265(0.62～2.55)和2.140(0.76～3.31);鱼眼镜头测定值依次为1.339(0.71～1.79)、1.491(1.11～1.92)和1.984(1.26～2.59).利用胸径-叶片半表面积模型测定的叶面积指数(范围)依次为4.53(2.24～6.34)、3.88(1.19～6.28)和6.63(3.5～8.37).间接仪器法测定的值明显小于实测值,但具有一定的相关性.胸径-叶片半表面积模型测定叶面积指数最为可靠,而鱼眼镜头测定法比冠层分析仪测定精度高.     

A new, model-free calculation method to determine the coordination modes and distribution of copper(II) among the metal binding sites of multihistidine peptides using circular dichroism spectroscopy

A new calculation method to determine microscopic protonation processes from CD spectra measured at different pH and Cu(II):ligand ratios was developed and used to give the relative binding strengths for the three histidines of hsPrP(84-114), a 31-mer polypeptide modeling the N-terminal copper(II) binding region of human (homo sapiens) prion protein. Mutants of hsPrP(84-114) with two or one histidyl residues have also been synthesized and their copper(II) complexes studied by CD spectroscopy. The 1-His models were analyzed first, and the molar CD spectra for the different coordination modes on the different histidines were calculated using the general computational program PSEQUAD. These spectra were deconvoluted into the sum of Gaussian curves and used as a first parameter set to calculate the molar spectra for the different coordination modes (3N and 4N coordination) and coordination positions (His85, His96 and His111) of the 2-His peptides. The calculation method therefore does not require the direct use of CD spectra measured in the smaller peptide models. This is a significant improvement over earlier calculation methods. In the same runs, the stepwise deprotonation pK(mic) values were refined and the pH-dependent distribution of copper(II) between the two histidines was determined. The results revealed the high, but different copper(II) binding affinities of the three separate histidines in the following order: His85 < His96His111. The calculation also showed that molar CD spectra which belong to the same coordination mode and coordination position in different ligands have very similar transition energies but different intensities. For this reason, direct transfer of molar CD spectra between different ligands may be a source of error, but the pK(mic) values and the copper(II) binding preferences are transferable from the 2-His peptides to the 3-His hsPrP(84-114).     

The effect of land type diversity and spatial heterogeneity on farmland birds in Norway

The decline in farmland birds observed throughout Europe during recent decades has attracted much attention. Agricultural intensification or land abandonment are commonly forwarded as key drivers. Several countries have established agri-environmental schemes (AES) to counter these negative trends among farmland birds. This paper reports a study of the relationship between land use and bird species in the agricultural landscape of Norway. The main objective was to investigate the effect of spatial heterogeneity and diversity of land use on total richness and abundance of farmland birds at a national level.Monitoring the distribution and abundance of birds is part of the Norwegian monitoring programme for agricultural landscapes. The monitoring programme is based on mapping of 1 × 1 km squares distributed across the entire agricultural landscape. Within these squares permanent observation points are established for bird monitoring. Detailed interpretation of aerial photographs provides the land classification. We tested the relationship between landscape metrics at different levels of land type detail and species richness and abundance of farmland and non-farmland birds.There was a positive relationship between species richness and abundance of farmland birds and agricultural area. For non-farmland birds the relationship was negative. Spatial heterogeneity of land use was a significant positive factor for both farmland and non-farmland species. High land type diversity was positive for farmland bird richness, but negative for abundance. Non-farmland bird richness was not affected by land type diversity, but abundance had a negative response.The results presented in this paper highlight the importance of a spatial heterogeneous landscape. However, we also found that land type diversity could negatively affect the abundance of both farmland and non-farmland birds. Our findings suggest a need for different management approaches depending on whether the aim is increased species richness or abundance. Achieving both aims with the same means might be difficult. We thus suggest a need for land use analyses before proper management strategies can be implemented.     

海鳗外周血细胞的显微结构

对海鳗外周血液有形成分用常规Wright氏和Giemsa氏染色并进行显微观察,可鉴别出红细胞、血栓细胞、淋巴细胞、单核细胞、中性粒细胞和酸性粒细胞;还见到幼稚的、正在分裂的、分解和解体状态的红细胞;未发现碱性粒细胞。红细胞数量多,椭圆形,具椭圆形核;白细胞中血栓细胞最多,分散分布,形态多样;淋巴细胞、单核细胞、中性和酸性粒细胞与其它鱼类的基本相似。     

A novel multiple subdivision-based algorithm for quantitative assessment of retinal vascular tortuosity

Vascular tortuosity as an indicator of retinal vascular morphological changes can be quantitatively analyzed and used as a biomarker for the early diagnosis of relevant disease such as diabetes. While various methods have been proposed to evaluate retinal vascular tortuosity, the main obstacle limiting their clinical application is the poor consistency compared with the experts’ evaluation. In this research, we proposed to apply a multiple subdivision-based algorithm for the vessel segment vascular tortuosity analysis combining with a learning curve function of vessel curvature inflection point number, emphasizing the human assessment nature focusing not only global but also on local vascular features. Our algorithm achieved high correlation coefficients of 0.931 for arteries and 0.925 for veins compared with clinical grading of extracted retinal vessels. For the prognostic performance against experts’ prediction in retinal fundus images from diabetic patients, the area under the receiver operating characteristic curve reached 0.968, indicating a good consistency with experts’ predication in full retinal vascular network evaluation.     

Structured Post-IQ Domain Governs Selectivity of Myosin X for Fascin-Actin Bundles

Without guidance cues, cytoskeletal motors would traffic components to the wrong destination with disastrous consequences for the cell. Recently, we identified a motor protein, myosin X, that identifies bundled actin filaments for transport. These bundles direct myosin X to a unique destination, the tips of cellular filopodia. Because the structural and kinetic features that drive bundle selection are unknown, we employed a domain-swapping approach with the nonselective myosin V to identify the selectivity module of myosin X. We found a surprising role of the myosin X tail region (post-IQ) in supporting long runs on bundles. Moreover, the myosin X head is adapted for initiating processive runs on bundles. We found that the tail is structured and biases the orientation of the two myosin X heads because a targeted insertion that introduces flexibility in the tail abolishes selectivity. Together, these results suggest how myosin motors may manage to read cellular addresses.