Lepidocrocite, an apatite mineral, and magnetic in teeth of chitons (Polyplacophora)

X-ray diffraction patterns show that the mature denticles of three extant chiton species are composed of the mineral lepidocrocite and an apatite mineral, probably francolite, in addition to magnetite. Each of the three minerals forms a discrete microarchitectural unit of the chiton denticles. This is the first indication that lepidocrocite is precipitated by marine organisms and an apatite mineral by chitons.     

Hemocyte-mediated shell mineralization in the eastern oyster

The growth of molluscan shell crystals is usually thought to be initiated from solution by extracellular organic matrix. We report a class of granulocytic hemocytes that may be directly involved in shell crystal production for oysters. On the basis of scanning electron microscopy (SEM) and x-ray microanalysis, these granulocytes contain calcium carbonate crystals, and they increase in abundance relative to other hemocytes following experimentally induced shell regeneration. Hemocytes are observed at the mineralization front using vital fluorescent staining and SEM. Some cells are observed releasing crystals that are subsequently remodeled, thereby at least augmenting matrix-mediated crystal-forming processes in this system.     

庭院丝瓜无公害栽培技术

丝瓜是蔓生农作物,适应性广、抗逆力强。不施化肥、不喷或少喷施农药栽培的鲜瓜为无公害绿色食品,尤其适宜庭院栽种,既美化居家环境,又拓宽种植领域。其关键栽培技术如下:1选择良种,杯钵育苗选用高产质嫩、含瓜络较少的鲜食丝瓜优良品种。为培育壮苗,增强抗逆力,一般采用营养钵     

Pancreatic zymogen granules differ markedly in protein composition

The activities of both chymotrypsin and amylase in individual zymogen granules of rat pancreas were measured by means of micromanipulation and microfluorometric methods. The enzyme content and the ratio of amylase to chymotrypsin varied widely among granules taken from the same animal. These results are compatible with short-term nonparallel bulk secretion of the two enzymes through exocytosis. The distribution of each enzyme activity in a population of granules suggests quantal packaging of amylase and chymotrypsinogen into the granules.     

Samarium-neodymium direct dating of fluorite mineralization

The direct dating of many styles of hydrothermal mineralization has proved difficult, limiting understanding of the geological processes that lead to crustal fluid flow and the formation of major ore deposits. The hydrothermal mineral fluorite (CaF(2)) displays large variations in rare earth element (REE) abundance and samarium/neodymium ratios within a single vein. Samarium-neodymium dating of fluorite from the classic granite-hosted tin deposits of southwest England demonstrates its use as a precise chronometer of mineralization. The concentrations of light rare earth elements (LREEs) in the fluorites are highly variable and suggest the coeval precipitation of an LREE-rich phase as the most likely cause of the extreme variation in samarium/neodymium ratios.     

Collagenase: localization in polymorphonuclear leukocyte granules in the rabbit

Polymorphonuclear leukocyte granules were submitted to zonal fractionation through a discontinuous sucrose gradient. Azurophilic and specific granules were enzymatically characterized by peroxidase and alkaline phosphatase activity, respectively. The enzymes formed modal distributions like those reported by others. Collagenase activity was consistently associated with the specific granules containing alkaline phosphatase.     

上海典型植物群落土壤有机碳矿化特征

选择上海市5种典型植物群落采样并布置室内恒温培养试验,观测了土壤有机碳矿化量大小及动态变化过程,并比较了不同植物群落土壤有机碳矿化特征差异。结果表明,不同群落间土壤有机碳、微生物量碳质量分数差异显著,但均高于草坪;而同一群落内土壤有机碳、微生物量碳则随土层深度的增加而逐渐下降;培养期间,土壤有机碳矿化量高低顺序为桂花Osmanthus fragrans＞草坪（黑麦草Lolium perenne）＞樟树Cinnamomum camphora＞池杉Taxodium ascendens＞竹林（孝顺竹Bambusa multiplex）,不同植物群落间差异达显著水平（P＜0.05）;同一群落土壤有机碳矿化量随土层的加深而递减,但不同群落间递减幅度存在差异,其中降幅最大为池杉,降幅最小分别为桂花（20 ～ 40 cm）和竹林（40 ～ 60 cm）;培养期间,各植物群落土壤有机碳矿化动态变化过程趋势相同,均表现为培养前期快速下降,培养后期保持相对稳定的趋势,与培养时间之间符合对数关系,而有机碳累计矿化量与培养时间则符合显著的线性关系,各群落高低顺序为桂花＞草坪＞樟树＞池杉＞竹林。研究结果初步表明,相对于草坪,深根系植物能有效提高土壤有机碳和微生物量碳,提高土壤有机碳库质量分数。图3表4参20     

Interocean differences in size and nutrition of coral reef sponge populations

Sponges consume an order of magnitude more organic matter on Caribbean coral reefs than on the Great Barrier Reef. This rate of consumption is attributed to Caribbean sponge biomass being five to six times greater than that on the Great Barrier Reef, on average, and to the absence in the Caribbean of phototrophic sponges, which are a feature of clean water regions of the Great Barrier Reef. The long temporal and spatial separation of the Atlantic and Pacific oceans has resulted in the evolution of dissimilar sponge faunas, with Caribbean sponges being heterotrophic, whereas many Great Barrier Reef sponges rely on nutritional input from photosynthetic symbionts.     

土壤中的铁及植物铁胁迫研究进展

铁是植物必需的微量元素，在植物的生命活动中起着重要的作用。文章从铁的性质、植物对铁的吸收和运输、植物对铁胁迫的反应以及与植物铁营养有关的基因的最新研究进展等方面进行了概述。并由此提出该领域今后的研究重点。     

Characterization of A-and B-type starch granules in Chinese wheat cultivars

Starch is the major component of wheat flour and serves as a multifunctional ingredient in food industry. The objective of the present study was to investigate starch granule size distribution of Chinese wheat cultivars, and to compare structure and functionality of starches in four leading cultivars Zhongmai 175, CA12092, Lunxuan 987, and Zhongyou 206. A wide variation in volume percentages of A- and B-type starch granules among genotypes was observed. Volume percentages of A- and B-type granules had ranges of 68.4–88.9% and 9.7–27.9% in the first cropping seasons, 74.1–90.1% and 7.2–25.3% in the second. Wheat cultivars with higher volume percentages of A- and B-type granules could serve as parents in breeding program for selecting high and low amylose wheat cultivars, respectively. In comparison with the B-type starch granules, the A-type granules starch showed difference in three aspects:(1) higher amount of ordered short-range structure and a lower relative crystallinity,(2) higher gelatinization onset(T_o) temperatures and enthalpies(ΔH), and lower gelatinization conclusion temperatures(T_c),(3) greater peak, though, and final viscosity, and lower breakdown viscosity and pasting temperature. It provides important information for breeders to develop potentially useful cultivars with particular functional properties of their starches suited to specific applications.     

HPLC-DAD法测定益母草颗粒中盐酸水苏碱含量的方法

【目的】建立HPLC-DAD测定益母草颗粒中盐酸水苏碱含量的方法,为益母草颗粒中盐酸水苏碱含量测定开发新的方法.【方法】采用Waters X Bridge HILIC色谱柱(4.6 mm×250 mm,5μm),以乙腈-水(80∶20)为流动相,流速为1 mL/min.【结果】盐酸水苏碱质量浓度在0.498 75～9.997 5μg范围内具有良好的线性关系(r=0.999 97),精密度、稳定性、重复性良好,平均加样回收率为109.89%,相对标准偏差(RSD)为1.03%.5批益母草颗粒中盐酸水苏碱的含量为5.09～5.11 mg/g.【结论】采用HPLC-DAD法测定盐酸水苏碱含量操作简便、结果准确,可作为益母草颗粒中盐酸水苏碱的含量测定方法.     

海绵校园建设中不同绿地类型雨水蓄滞能力研究

为应对校园内每逢下雨便会产生的积水问题,以宝鸡文理学院东校区为例,用称重法测定不同植被条件下0～30 cm平均土壤含水率的变化,并分析不同绿地类型的分布特征,用SPSS 20.0等相关软件对测量数据进行统计分析。结果表明,平均土壤含水率表层(0～10 cm)亚表层(10～20 cm)20～30 cm土层;乔木林地雨后平均土壤含水率表现为银杏(Ginkgo biloba L.)雪松[Cedrus deodara (Roxb.) G.Don]樱花树(Cerasus yedoensis)龙爪槐(Sophora japonica)柿子树(Diospyro skaki Thunb)红叶李(Prunus cerasifera);灌草地雨后平均土壤含水率表现为红叶石楠(Photinia×fraseri Dress)复层植被草坪金竹(Phyllostachys sulphurea)大叶黄杨(Euonymus japonicus Thunb)。疏林较密林更容易吸收降水量,乔木林地较灌草地含有高水分值,而草地较稠密灌木林地来说更易减少降水的流失。     

糯玉米胚乳淀粉粒的粒度分布特征

以7个糯玉米品种为材料,采用激光衍射粒度分析仪测定其胚乳淀粉粒粒径以及体积、表面积和数目的分布,明确糯玉米胚乳淀粉粒的粒度分布特征。结果表明:糯玉米胚乳淀粉粒的粒径为0.375—30.07μm,其上限为22.73—30.07μm,平均粒径为12.33-14.60μm。淀粉粒的体积和表面积分布呈现三峰曲线,数目分布呈现单峰曲线。以体积分布曲线凹处为界线将糯玉米淀粉粒分为小型(3.519μm)、中型(3.519—7.422μm)和大型(7.422μm)。7个糯玉米品种小型、中型和大型淀粉粒体积分别占总体积的11.25%—12.46%、1.79%—6.98%和80.77%—86.96%,表面积分别占总表面积的54.28%—57.13%、2.50%—8.26%和35.97%—40.38%,数目分别占总数目的98.71%—99.39%、0.20%—0.76%和0.39%—0.53%。可见,糯玉米胚乳淀粉主要由小型淀粉粒组成,其对表面积的贡献最大,而大型淀粉粒对体积的贡献最大。品种间比较,小型淀粉粒的粒度分布差异不显著,中型和大型淀粉粒的粒度分布存在显著差异。     

Peroxidase mediated antimicrobial activities of alveolar macrophage granules

The 20,000g pellet obtained by centrifugation of a homogenate of rabbit alveolar macrophages has antibacterial activity in the presence of a hydrogen peroxide-generating system and iodide. Peroxidase activity has been demonstrated in this fraction. Addition of 3-amino-1,2,4-triazole diminished the antibacterial activity of the pellet-hydrogen peroxide-iodide system.     

Interdecadal variation in an antarctic sponge and its predators from oceanographic climate shifts

During the 1960s there was extensive formation of anchor ice to depths of 30 meters at McMurdo Station, Antarctica. During this period the sponge Homaxinella balfourensis was rare, as were its predators in that depth zone. Most of the existing sponges were killed by anchor ice. During the 1970s, anchor ice formation was reduced, and there was a massive recruitment of Homaxinella, which covered as much as 80 percent of the substrata in that zone. Many predators appeared but did not control the sponge population, and it continued to grow through that decade. The early 1980s were characterized by ice formation and almost all of the Homaxinella were eliminated, leaving an order of magnitude more predators in that zone. The interdecadal increases in anchor ice probably result from local upwelling of extremely cold deep water, possibly in response to shifts in the strengths of regional currents.     

预培养温度对稻田土壤氮素矿化影响

为明确预培养温度对氮素矿化影响,选择南北方典型稻田土壤,经12、25和35℃预培养2周后,与风干土一起恒温培养28 d(25℃),测定培养前后铵态氮含量,分析预培养过程中土壤有机氮组分变化。结果表明,随预培养温度升高,初始铵态氮含量逐渐增加,矿化氮含量逐渐减少,当预培养温度为35℃时,矿化氮含量甚至降为负值。虽然12和25℃预培养不会影响土壤总矿化氮含量,但模型拟合显示,风干土矿化过程与经预培养的土壤矿化过程明显不同。风干土直接培养2周或经25℃预培养2周后,可酸解氮含量均有所增加,难酸解氮含量明显降低;与风干土相比,12℃预培养有机氮组分变化不明显;而随预培养温度升高,酸解氮含量先增后减,难酸解氮先减后增。可见,难酸解氮在矿化过程中可能也发挥重要作用。35℃预培养温度会改变土壤供氮过程,12℃预培养后土壤有机氮组分变化较小,矿化过程更符合实际。因此,测定土壤氮素矿化应以12℃作为预培养条件。     

26个丝瓜品种引种观察

对引入的31份丝瓜品种资源进行农艺性状、瓜条性状及抗性观察，发现目前栽培丝瓜以早熟品种为主，瓜条长度小于30cm的占68.75%，平均瓜条粗径为4.85cm，缺少瓜条长度及粗细适中、高产、优质的品种。也未发现对瓜类上最主要的病害－－病毒病的抗源。     

High abrasion resistance with sparse mineralization: copper biomineral in worm jaws

Biominerals are widely exploited to harden or stiffen tissues in living organisms, with calcium-, silicon-, and iron-based minerals being most common. In notable contrast, the jaws of the marine bloodworm Glycera dibranchiata contain the copper-based biomineral atacamite [Cu2(OH)3Cl]. Polycrystalline fibers are oriented with the outer contour of the jaw. Using nanoindentation, we show that the mineral has a structural role and enhances hardness and stiffness. Despite the low degree of mineralization, bloodworm jaws exhibit an extraordinary resistance to abrasion, significantly exceeding that of vertebrate dentin and approaching that of tooth enamel.