Beobachtungen an sozialbezogenen Verhaltensweisen von Sammelbienen

Mit Hilfe neuer Registriermethoden wurden der Saugvorgang und das Duftmarkieren bei Sammelbienen in Abhängigkeit vom Zuckerwasserangebot an der Futterquelle untersucht. Wenn an einer Futterquelle das Angebot ergiebig ist, wirbt die Sammelbiene Neulinge an. Ein Teil des erhöhten Angebotes wird durch die Neulinge aufgefangen, jedoch wächst die Neulingszahl nicht proportional zur Erhöhung des Angebotes. Anwerbung im Stock und Wettbewerb zwischen den Sammelbienen an der Futterquelle schließen einen Regelkreis. Dadurch gleicht sich diese Sammelschar jederzeit dem veränderlichen Angebot an der Futterquelle an. Durch Änderung des Angebots an der Futterquelle lassen sich die Schwelle für das Duftmarkieren bestimmen und verschiedene Intensitätsstufen des Duftmarkierens unterscheiden. Bei konstantem Angebot an der Futterquelle lassen sich Schwankungen in der Dauer des Duftmarkierens und der Länge der Saugdauer bzw. der Größe der Abflugmagenfüllung ablesen, die gewisse Gesetzmäßigkeiten aufweisen. Mit Hilfe von Funktionsschemata werden Deutungen für diese Erscheinungen vorgeschlagen.     

Reproductive Outcomes Following Ectopic Pregnancy: Register-Based Retrospective Cohort Study

Background

We aimed to compare reproductive outcomes following ectopic pregnancy (EP) versus livebirth, miscarriage, or termination in a first pregnancy.

Methods And Findings

A retrospective cohort study design was used. Scottish national data on all women whose first pregnancy occurred between 1981 and 2000 were linked to records of a subsequent pregnancy. The exposed cohort comprised women with an EP in their first pregnancy. There were three unexposed cohorts: women with livebirth, miscarriage, and termination of their first pregnancies. Any differences in rates of second pregnancy, livebirth, EP, miscarriage, or terminations and complications of a second ongoing pregnancy and delivery were assessed among the different exposure groups. A total of 2,969 women had an initial EP; 667,299 had a livebirth, 39,705 women miscarried, and 78,697 terminated their first pregnancies. Women with an initial EP had an increased chance of another pregnancy within 2 years (adjusted hazard ratio (AHR) 2.76 [95% CI 2.58–2.95]) or after 6 years (AHR 1.57 [95% CI 1.29–1.91]) compared to women with a livebirth. In comparison with women with an initial miscarriage, women who had an EP had a lower chance of a second pregnancy (AHR 0.53 [95% CI 0.50–0.56]). Compared to women with an initial termination, women with an EP had an increased chance of a second pregnancy (AHR 2.38 [95% CI 2.23–2.55]) within 2 years. Women with an initial EP suffered an increased risk of another EP compared to women with a livebirth (AHR 13.0 [95% CI 11.63–16.86]), miscarriage (AHR 6.07 [95% CI 4.83–7.62]), or termination (AHR 12.84 [95% CI 10.07–16.37]). Perinatal complications in a pregnancy following EP were not significantly higher than those in primigravidae or in women with a previous miscarriage or termination.

Conclusion

Women with an initial EP have a lower chance of conception than those who miscarry but an increased risk of a repeat EP in comparison with all three comparison groups. A major limitation of this study was the inability to separate women using contraception from those who were intending to conceive. Please see later in the article for the Editors'' Summary     

Suprabenthic Peracarida (Crustacea, Malacostraca) sampled at 75°N off East Greenland

During an expedition with RV Polarstern in 1994 samples were taken at 75°N off Greenland, by means of an epibenthic sledge, which was equipped with an epi- and an additional suprabenthic net with an opening 1–1.33 m above the seafloor. Within the Peracarida (Crustacea, Malacostraca) sampled, 12 species were more frequent in the suprabenthic net, while 8 species were only sampled in this upper net. Received: 9 August 1996 / Accepted: 1 October 1996     

Enzymatic Synthesis of N-formyl-L-aspartyl-L-phenylalanine Methyl Ester (Aspartame Precursor) Utilizing an Extractive Reaction in Aqueous/Organic Biphasic Medium

N-Formyl-L-aspartyl-L-phenylalanine methyl ester (N-formyl aspartame, F-AspPheOMe) was synthesized enzymatically utilizing an extractive reaction in an aqueous/organic biphasic system. The N-formyl aspartame yield in a pure aqueous monophasic system was, in general, ca. 3% , however, it was over 80 % in a water/1-butanol biphasic system using a simultaneously extractive operation of an enzymatic reaction in an aqueous phase and a product separation from an aqueous to an organic phases.     

Array CGH characterization of an unbalanced X-autosome translocation associated with Xq27.2–qter deletion, 11q24.3–qter duplication and Xq22.3–q27.1 duplication in a girl with primary amenorrhea and mental retardation

We present array comparative genomic hybridization (aCGH) characterization of an unbalanced X-autosome translocation with an Xq interstitial segmental duplication in a 16-year-old girl with primary ovarian failure, mental retardation, attention deficit disorder, learning difficulty and facial dysmorphism. aCGH analysis revealed an Xq27.2–q28 deletion, an 11q24.3–q25 duplication, and an inverted duplication of Xq22.3–q27.1. The karyotype was 46,X,der(X)t(X;11)(q27.2;q24.3) dup(X)(q27.1q22.3). We discuss the genotype–phenotype correlation in this case. Our case provides evidence for an association of primary amenorrhea and mental retardation with concomitant unbalanced X-autosome translocation and X chromosome rearrangement.     

Biosynthesis of polymyxin E III. Total synthesis of polymyxin E by a cell-free enzyme system

Polymyxin E, an antimicrobial branched cyclic decapeptide, was synthesized by an enzyme fraction partially purified from crude extracts of the producing organism, $\text{Aerobacillus}\text{polyaerogenes}$. For the synthesis, three constituent amino acids (L-2,4-diaminobutyric acid, L-leucine, and L-threonine), ATP, Mg²⁺ and an acylating system consisting of octanoyl CoA and an ammonium sulfate fraction of cell extracts are required.     

基于临床肿瘤标本的胃癌转移模型建立

目的建立基于临床肿瘤标本的胃癌转移模型,为胃癌的转移研究提供个体化动物模型。方法将胃癌新鲜的手术标本移植到裸鼠皮下,建立胃癌患者异种移植(patient-derived xenograft,PDX)模型。进一步通过手术将皮下瘤组织原位移植到裸鼠胃部肌层,连续观察裸鼠的体征状态,通过近红外荧光活体成像技术检测肿瘤转移的发生。解剖荷瘤小鼠,将肺部转移灶进一步移植裸鼠皮下获得实体瘤。HE染色观察原发瘤与转移瘤的结构特征,(short tandem repeat) STR分析原发瘤和转移瘤的遗传特性。PCR-Array分析转移瘤和原发瘤中转移相关基因的表达。结果成功建立胃癌PDX模型,移植瘤组织结构与患者保持基本一致;通过胃部原位移植发现编号C19751的小鼠发生肺和肝的转移。其中肺转移灶皮下移植后获得了实体瘤,STR分析显示原发瘤保持了与肺转移瘤一致的遗传特征。PCR-Array结果显示,与原发瘤相比,转移瘤中CXCL12,IGF1和MMP2基因表达均显著上调。结论利用临床肿瘤标本成功建立胃癌转移模型,为胃癌转移研究提供了良好的个体化模型。     

Light Scattering Investigation of Electric Field Alignment of Phospholipid Tubules

The polymerizable diacetylenic phospholipid 1,2-bis(10,12,tricosadiynoyl)-sn-glycero-3-phosphocholine (DC₂₃PC) forms straight hollow cylinders in water. Using an ac electric field it was possible to achieve significant orientational alignment of the tubules parallel to the field direction, and from light scattering results deduce an effective dielectric susceptibility anisotropy Δχ_E. Moreover, we suggest that the alignment arises from an orientational anisotropy of the total electrostatic enthalpy for a dielectric tubule in an electric field, rather than an inherent polarizability anisotropy of the constituent DC₂₃PC molecules, as was the case with magnetic field alignment.     

A noninvasive approach to determine viscoelastic properties of an individual adherent cell under fluid flow

Mechanical properties of cells play an important role in their interaction with the extracellular matrix as well as the mechanotransduction process. Several in vitro techniques have been developed to determine the mechanical properties of cells, but none of them can measure the viscoelastic properties of an individual adherent cell in fluid flow non-invasively. In this study, techniques of fluid–structure interaction (FSI) finite element method and quasi-3-dimensional (quasi-3D) cell microscopy were innovatively applied to the frequently used flow chamber experiment, where an adherent cell was subjected to fluid flow. A new non-invasive approach, with cells at close to physiological conditions, was established to determine the viscoelastic properties of individual cells. The results showed an instantaneous modulus of osteocytes of 0.49±0.11 kPa, an equilibrium modulus of 0.31±0.044 kPa, and an apparent viscosity coefficient of 4.07±1.23 kPa s. This new quantitative approach not only provides an excellent means to measure cell mechanical properties, but also may help to elucidate the mechanotransduction mechanisms for a variety of cells under fluid flow stimulation.     

An atypical RNA pseudoknot stimulator and an upstream attenuation signal for -1 ribosomal frameshifting of SARS coronavirus

The −1 ribosomal frameshifting requires the existence of an in cis RNA slippery sequence and is promoted by a downstream stimulator RNA. An atypical RNA pseudoknot with an extra stem formed by complementary sequences within loop 2 of an H-type pseudoknot is characterized in the severe acute respiratory syndrome coronavirus (SARS CoV) genome. This pseudoknot can serve as an efficient stimulator for −1 frameshifting in vitro. Mutational analysis of the extra stem suggests frameshift efficiency can be modulated via manipulation of the secondary structure within the loop 2 of an infectious bronchitis virus-type pseudoknot. More importantly, an upstream RNA sequence separated by a linker 5′ to the slippery site is also identified to be capable of modulating the −1 frameshift efficiency. RNA sequence containing this attenuation element can downregulate −1 frameshifting promoted by an atypical pseudoknot of SARS CoV and two other pseudoknot stimulators. Furthermore, frameshift efficiency can be reduced to half in the presence of the attenuation signal in vivo. Therefore, this in cis RNA attenuator represents a novel negative determinant of general importance for the regulation of −1 frameshift efficiency, and is thus a potential antiviral target.     

Interference between cues of the same outcome in a non-causally framed scenario

Retroactive interference between cues of the same outcome (i.e., IbC) occurs when the behavioral expression of an association between a cue and an outcome (e.g., A → O1) is reduced due to the later acquisition of an association between a different cue and the same outcome (e.g., B → O1). Though this interference effect has been traditionally explained within an associative framework, there is recent evidence showing that IbC effect may be better understood in terms of the operation of higher order causal reasoning processes. The results from Experiments 1 and 2 showed an IbC effect in a learning task within a game scenario suggesting non-causal relationships between events. Thus, these results showed that IbC may have a diverse origin, one of them being of an associative nature.     

The suitability of some plant hosts for the development of the peach-potato aphid, Myzus persicae (Sulzer)

Myzus persicae develop well on Brassica species, particularly those that grow rapidly, such as mustard and turnip, but much less well on sugar beet, spinach and lettuce. They usually develop better on young, rapidly growing leaves than on mature leaves. Two clones of M. persicae behaved similarly on the host plants tested.

---

Zusammenfassung Die Entwicklung von Myzus persicae-Alienicolen auf den Sekundärwirten Kohlrüben, Kopfkohl, Chinakohl, Brokkoli, Blumenkohl, Senf, Raps, Grünkohl sowie Zuckerrübe, Spinat und Salat wurde durch wiederholte Erfassung der durchschnittlichen und totalen Larvenproducktion einzelner Jungfern sowie ihrer Mortalität in Gewächshausversuchen verfolgt und mit Auszählung des Befalls von Freilandpflanzen verglichen. Myzus persicae entwickelte sich gut an Brassica-Arten, besonders an raschwüchsigen wie Senf und Kohlrüben, aber viel weniger gut an Zuckerrübe, Spinat and Salat. Sie entwickelt sich gewöhnlich an jungen schnell wachsenden Blättern besser als an ausgereiften. Zwei Klone von Myzus persicae verhielten sich an den geprüften Wirtspflanzen ähnlich.

     

Über Plasmadifferenzierungen in Plasmodien der Schleimpilze

Ohne ZusammenfassungMeinem hochverehrten Lehrer, Herrn Prof. Dr. Küster, sei auch an dieser Stelle für sein großes Interesse an dieser Arbeit und seine allzeit freundliche Unterstützung Dank gesagt. Dem Assistenten, Herrn Dr. Heidt, sei ebenfalls für seine Anteilnahme an der Arbeit gedankt.     

Tolypocladium cylindrosporum gams (deuteromycetes,moniliaceae) as a biological control agent against the window midge Sylvicola cinctus Fabr. (diptera: Anisopodidae)

Larvae of Sylvicola cinctus Fabr. were found killed by an entomopathogenic fungus Tolypocladium cylindrosporum Gams, in Vetlanda, Sweden. This is the first report of this fungus as an insect pathogen from Sweden. The fungus was cultured and sprayed on aspen log piles in an attempt to reduce population levels. In September 1992, when maximum abundance is expected, the area treated with T. cylindrosporum had significantly fewer midges than an untreated area. Possibilities for biological control are discussed.     

The purification by affinity chromatography of a glutathione S-transferase from larvae of Galleria mellonella

Glutathione-sulphobromophthalein conjugate, covalently linked to an agarose matrix, acts as an affinity chromatographic medium for a glutathione S-transferase from $\text{Galleria mellonella}$. In a three step preparation, an enzyme of 98% purity is obtained, in 30% yield.     

富平石川河的生态修复

自国家提出构建山水林田湖草生命共同体以来,已启动第三批山水林田湖草生态保护修复工程试点申报,但一些工程设计缺乏整体性,造成“真破坏”和“伪生态”的现象时有发生.本研究以石川河综合整治项目为例,针对石川河乱采乱挖河道砂石,工业污染,附近村民焚烧垃圾造成气、水和土污染极其严重,生态、人居环境持续恶化,鱼虾绝迹,污水横流,垃圾成堆等问题,采用重建生态河道、恢复生态、景观重塑、土地平整、PE复合土工膜、土壤修复等技术构建山水林田湖草生命共同体,并分析了生态、经济和社会效益,通过项目实施,为石川河流域提供了洁净的土壤环境、稳定的土体结构,有效改善了生态环境,提高了生活质量,实现生产发展、生态良好,不断满足社会发展建设美丽乡村的需要,同时为构建流域山水林田湖草生命共同体提供理论依据和实践支撑.     

Charging of submicron structures during silicon dioxide etching in one- and two-frequency gas discharges

A model that combines the Monte Carlo method for calculating electron and ion trajectories in three-dimensional geometry and an analytic approach developed for calculating an electric field in two-dimensional geometry is used to simulate the charging of the surface of periodic submicron SiO₂ structures by electron and ion fluxes in the plasma of a one- and a two-frequency capacitive RF discharge. The energy distribution function of the electrons and ions that come to the bottom of a submicron structure in an argon and an argon-containing plasma is calculated for structures with a width of 11–45 nm and an aspect ratio of d/w = 1–10 (where d and w are the depth and width of the structure). It is shown that secondary electronelectron emission plays an important role in the redistribution of the electric charge and, accordingly, of the electric potential in a submicron structure. It is demonstrated that, when the secondary electron-electron emission mechanism is taken into account, the ion energy spectrum at the bottom of a submicron structure is shifted toward lower energies and becomes broader in comparison with the spectrum of an ion flux from an RF discharge plasma. Moreover, the shift and broadening depend only on the secondary electron-electron emission coefficient, the energy of the charged particles, and the aspect ratio.     

The Role of Antireflective Coating CYTOP,Immersion Oil,and Sensitizer Selection in Fabricating a 2.3 V, 10% Power Conversion Efficiency SSM‐DSC Device

Sequential series multijunction dye‐sensitized solar cells (SSM‐DSCs) can power solar‐to‐fuel processes with a single illuminated area device. Dye selection and strategies limiting photon losses are critical in SSM‐DSC devices for higher performance systems. Herein, an efficient and readily applicable spin coating protocol on glass surfaces with an antireflective fluoropolymer (CYTOP) is applied to an SSM‐DSC architecture. Combining CYTOP with the use of an immersion oil between glass spacers in a three subcell SSM‐DSC with judiciously selected TiO₂ photoanode sensitizers and thicknesses, an overall power conversion efficiency (PCE) of 10.1% is obtained with an output of 2.3 V. Without external bias, this SSM‐DSC configuration shows an impressive overall solar‐to‐fuel conversion efficiency of 6% when powering IrO₂ and Au₂O₃ electrocatalysts for CO₂ and H₂O to CO and H₂ conversion in aqueous solution. The role of CYTOP, immersion oil, sensitizer selection, and film thickness on SSM‐DSC devices is discussed along with the stability of this system.     

An inclusive fitness analysis of synergistic interactions in structured populations

We study the evolution of a pair of competing behavioural alleles in a structured population when there are non-additive or ‘synergistic’ fitness effects. Under a form of weak selection and with a simple symmetry condition between a pair of competing alleles, Tarnita et al. provide a surprisingly simple condition for one allele to dominate the other. Their condition can be obtained from an analysis of a corresponding simpler model in which fitness effects are additive. Their result uses an average measure of selective advantage where the average is taken over the long-term—that is, over all possible allele frequencies—and this precludes consideration of any frequency dependence the allelic fitness might exhibit. However, in a considerable body of work with non-additive fitness effects—for example, hawk–dove and prisoner''s dilemma games—frequency dependence plays an essential role in the establishment of conditions for a stable allele-frequency equilibrium. Here, we present a frequency-dependent generalization of their result that provides an expression for allelic fitness at any given allele frequency p. We use an inclusive fitness approach and provide two examples for an infinite structured population. We illustrate our results with an analysis of the hawk–dove game.