Pollen,ovules, and pollination in pea: Success,failure, and resilience in heat

Field pea (Pisum sativum), a major grain legume crop, is autogamous and adapted to temperate climates. The objectives of this study were to investigate effects of high temperature stress on stamen chemical composition, anther dehiscence, pollen viability, pollen interactions with pistil and ovules, and ovule growth and viability. Two cultivars (“CDC Golden” and “CDC Sage”) were exposed to 24/18°C (day/night) continually or to 35/18°C for 4 or 7 days. Heat stress altered stamen chemical composition, with lipid composition of “CDC Sage” being more stable compared with “CDC Golden.” Heat stress reduced pollen viability and the proportion of ovules that received a pollen tube. After 4 days at 35°C, pollen viability in flower buds decreased in “CDC Golden,” but not in “CDC Sage.” After 7 days, partial to full failure of anthers to dehisce resulted in subnormal pollen loads on stigmas. Although growth (ovule size) of fertilized ovules was stimulated by 35°C, heat stress tended to decrease ovule viability. Pollen appears susceptible to stress, but not many grains are needed for successful fertilization. Ovule fertilization and embryos are less susceptible to heat, but further research is warranted to link the exact degree of resilience to stress intensity.     

基于网络分析的城市生态空间结构优化——以常州市为例

经济社会的高速发展带来城市的快速扩张,造成城市生态空间的萎缩和生态功能的下降,城市生态安全受到严重威胁。系统研究城市生态空间结构,提出针对性保护和优化措施,对于城市的可持续发展具有重大意义。本研究以常州市为研究区,考虑城市生态空间的自然生态功能和社会服务功能两方面,构建基于自然生态的“源地-廊道”与基于人文生态的“供给-需求”两类生态网络,对于源地廊道生态网络,主要从节点重要性、网络连通性与稳定性进行定量分析,对于供给需求生态网络,主要从节点重要性、供需均衡与稳定性进行定量分析。结果表明: 常州市主城区源地廊道生态网络的连通性与稳定性水平不高,供给需求生态网络的稳定性水平一般且存在服务供给与需求的空间错位。从连通性与稳定性提升角度,提出新增12个源地节点与57条廊道的源地廊道生态网络优化方案;从供需均衡与稳定性提升角度,提出新增22个供给节点的供给需求生态网络优化方案。对比初始源地廊道生态网络,优化网络连通性水平提升10%,稳定性提升0.05;对比初始供给需求生态网络,优化网络的服务水平提升4%,网络稳定性提升0.10。最后,综合两类生态网络,分别针对现状保护斑块与新增节点两类对象,提出了保护与管理实施方案。     

Multiorgan microfluidic platform with breathable lung chamber for inhalation or intravenous drug screening and development

Efficient and economical delivery of pharmaceuticals to patients is critical for effective therapy. Here we describe a multiorgan (lung, liver, and breast cancer) microphysiological system (“Body-on-a-Chip”) designed to mimic both inhalation therapy and/or intravenous therapy using curcumin as a model drug. This system is “pumpless” and self-contained using a rocker platform for fluid (blood surrogate) bidirectional recirculation. Our lung chamber is constructed to maintain an air-liquid interface and contained a “breathable” component that was designed to mimic breathing by simulating gas exchange, contraction and expansion of the “lung” using a reciprocating pump. Three cell lines were used: A549 for the lung, HepG2 C3A for the liver, and MDA MB231 for breast cancer. All cell lines were maintained with high viability (>85%) in the device for at least 48 hr. Curcumin is used to treat breast cancer and this allowed us to compare inhalation delivery versus intravenous delivery of the drug in terms of effectiveness and potentially toxicity. Inhalation therapy could be potentially applied at home by the patient while intravenous therapy would need to be applied in a clinical setting. Inhalation therapy would be more economical and allow more frequent dosing with a potentially lower level of drug. For 24 hr exposure to 2.5 and 25 µM curcumin in the flow device the effect on lung and liver viability was small to insignificant, while there was a significant decrease in viability of the breast cancer (to 69% at 2.5 µM and 51% at 25 µM). Intravenous delivery also selectively decreased breast cancer viability (to 88% at 2.5 µM and 79% at 25 µM) but was less effective than inhalation therapy. The response in the static device controls was significantly reduced from that with recirculation demonstrating the effect of flow. These results demonstrate for the first time the feasibility of constructing a multiorgan microphysiological system with recirculating flow that incorporates a “breathable” lung module that maintains an air-liquid interface.     

“SORBOSE TOXICITY” IN NEUROSPORA

Brockman, II. E., and F. J. de Serres. (Oak Ridge Natl. Lab., Oak Ridge, Tenn.) “Sorbose toxicity” in Neurospora . Amer. Jour. Bot. 50(7): 709–714. Illus. 1963.—The effect of “sorbose toxicity” on Neurospora conidia or ascospores was compared in sorbose-fructose-glucose (S-F-G) and sorbose-sucrose (S-S) media. Many frequently encountered and difficultly controlled experimental variables may strongly affect viability in S-S media but are essentially without effect in S-F-G media. The viabilities of different mutant strains are affected to varying extents by autoclave exposure time of the S-S media but not of the S-F-G media. Ascospores are more sensitive than conidia to “sorbose kill” in S-S media. An over plating method described by New meyer (1954) for increasing ascospore “viability” is without effect when sucrose is replaced with fructose and glucose. In all experiments in which sorbose was added to induce colonial growth, “sorbose toxicity” or “sorbose kill” was eliminated or minimized by replacing sucrose with a mixture of fructose and glucose as the carbon source for Neurospora media.     

Comparison of cryopreservation methods for the long term storage of the marine diatom Haslea ostrearia (simonsen)

Long term maintenance of microalgal strains by serial subculturing is often expensive and time-consuming. Alternative methods, such as cryopreservation, present several benefits and thus seem more relevant. Our study aimed at comparing two cryopreservation procedures applied to the marine diatom Haslea ostrearia (Simonsen): (1) a two-step freezing method in liquid media using 5%, 10% and 20% MeOH, Me₂SO or Glycerol, and (2) an immobilization-dehydration method consisting in an algal cell entrapped in 0.7 M sucrose dehydrated and air-flow desiccated calcium alginate beads before “direct” or “two-step” freezing. Our results showed that the cryopreservation of H. ostrearia was feasible. With the two-step freezing protocol only Me₂SO maintained cell viability without contamination but the low percentage of viability (<10%) prevents its use. Conversely, the immobilization-dehydration methods tested in this study were effective. Average viability of 57% and 77% were obtained with the “direct” and the “two step” cooling assays respectively, ensuring preservation of the genetic traits of H. ostrearia.     

Patterns of sensitivity of association measures in numerical taxonomy

Numerical taxonomy and the related methods of multidimensional scaling (MDS) have been applied in a wide range of disciplines in the last twenty-five years. A common feature has been the initial derivation of a measure of association or proximity among pairs of objects from a multivariate data matrix. Although a large number of measures are in use, there has been little systematic study of the sensitivities of these measures to different aspects of character data. I report here a general model, for a class of these measures, that reveals basic patterns of sensitivity that underlie a wide variety of common measures and shows that there is a continuum of potential association measures which exhibit useful combinations of sensitivities. I distinguish between “separation” sensitive and “minimum value” sensitive measures and describe a new measure that is intermediate in exhibiting both minimum value and separation sensitivity. The utility of this new type of measure in three disciplines—ecology, psychology, and systematics—is briefly described.     

Adults' responses to infants varying in perceived cuteness

The effects of perceived cuteness of infant photographs on the behaviour of young adults was investigated. Looking, facial muscle activity, and skin conductance were measured during individual presentations of the photographs, whereas only looking was measured during paired presentations. Both measures of looking time were significantly affected by the perceived cuteness of infant photographs, with infants ranked as most cute looked at longest and those ranked least cute looked at for the shortest length of time. Increased facial muscle activity previously associated with pleasant or happy facial expressions was associated with presentations of infant photographs but was not related to perceived cuteness. A second experiment indicated that increased facial muscle activity was specific to infant photographs. Adult responses to infant physical appearance appear to be regulated by two mechanisms: an initial positive response to “babyishness”, reflected by increased facial zygomaticus muscle activity, and an individual cognitive preference response to “cuteness”, reflected by differential looking times.     

THE EVOLUTION OF COSTLY MATE PREFERENCES II. THE “HANDICAP” PRINCIPLE

We use a general additive quantitative genetic model to study the evolution of costly female mate choice by the “handicap” principle. Two necessary conditions must be satisfied for costly preference to evolve. The conditions are (i) biased mutation pressure on viability and (ii) a direct relationship between the degree of expression of the male mating character and viability. These two conditions explain the success and failure of previous models of the “handicap” principle. Our model also applies to other sources of fitness variation like migration and host-parasite coevolution, which cause effects equivalent to biased mutation.     

Mouse ES cells maintained in different pluripotency-promoting conditions differ in their neural differentiation propensity

Prior to differentiation, embryonic stem (ES) cells in culture are maintained in a so-called “undifferentiated” state, allowing derivation of multiple downstream cell lineages when induced in a directed manner, which in turn grants these cells their “pluripotent” state. The current work is based on a simple observation that the initial culture condition for maintaining mouse ES cells in an “undifferentiated” state does impact on the differentiation propensity of these cells, in this case to a neuronal fate. We point out the importance in judging the “pluripotency” of a given stem cell culture, as this clearly demonstrated that the “undifferentiated” state of these cells is not necessarily a “pluripotent” state, even for a widely used mouse ES cell line. We partly attribute this difference in the initial value of ES cells to the naïve-to-primed status of pluripotency, which in turn may affect early events of the differentiation in vitro.     

Die revidierte Impact of Event-Skala (IES-R)

In response to an extremely stressful event such as a severe accident, rape or assault, human beings may develop posttraumatic stress disorder (PTSD). One of the most widely used and translated self-report measures for assessing the degree of a symptomatic response to a specific traumatic event is the Impact of Event Scale (IES) originally published in 1979. The IES comprises two subscales “Intrusion” and “Avoidance” and was revised in 1997 (IES-R). The IES-R has three subscales, i.e. “Intrusion”, “Avoidance”, and “Hyperarousal”. Psychometric properties of the IES-R are satisfactory. The IES-R is not intended to be used as a proxy for a diagnosis of PTSD but rather allows an estimation of symptom severity.     

Ectogestation ethics: The implications of artificially extending gestation for viability,newborn resuscitation and abortion

Recent animal research suggests that it may soon be possible to support the human fetus in an artificial uterine environment for part of a pregnancy. A technique of extending gestation in this way (“ectogestation”) could be offered to parents of extremely premature infants (EPIs) to improve outcomes for their child. The use of artificial uteruses for ectogestation could generate ethical questions because of the technology’s potential impact on the point of “viability”—loosely defined as the stage of pregnancy beyond which the fetus may survive external to the womb. Several medical decisions during the perinatal period are based on the gestation at which infants are considered viable, for example decisions about newborn resuscitation and abortion, and ectogestation has the potential to impact on these. Despite these possible implications, there is little existing evidence or analysis of how this technology would affect medical practice. In this paper, we combine empirical data with ethical analysis. We report a survey of 91 practicing Australian obstetricians and neonatologists; we aimed to assess their conceptual understanding of “viability,” and what ethical consequences they envisage arising from improved survival of EPIs. We also assess what the ethical implications of extending gestation should be for newborn and obstetric care. We analyze the concept of viability and argue that while ectogestation might have implications for the permissibility of neonatal life-prolonging treatment at extremely early gestation, it should not necessarily have implications for abortion policy. We compare our ethical findings with the results of the survey.     

Microbial expansion–collision dynamics promote cooperation and coexistence on surfaces

Microbes colonizing a surface often experience colony growth dynamics characterized by an initial phase of spatial clonal expansion followed by collision between neighboring colonies to form potentially genetically heterogeneous boundaries. For species with life cycles consisting of repeated surface colonization and dispersal, these spatially explicit “expansion‐collision dynamics” generate periodic transitions between two distinct selective regimes, “expansion competition” and “boundary competition,” each one favoring a different growth strategy. We hypothesized that this dynamic could promote stable coexistence of expansion‐ and boundary‐competition specialists by generating time‐varying, negative frequency‐dependent selection that insulates both types from extinction. We tested this experimentally in budding yeast by competing an exoenzyme secreting “cooperator” strain (expansion–competition specialists) against nonsecreting “defectors” (boundary–competition specialists). As predicted, we observed cooperator–defector coexistence or cooperator dominance with expansion–collision dynamics, but only defector dominance otherwise. Also as predicted, the steady‐state frequency of cooperators was determined by colonization density (the average initial cell–cell distance) and cost of cooperation. Lattice‐based spatial simulations give good qualitative agreement with experiments, supporting our hypothesis that expansion–collision dynamics with costly public goods production is sufficient to generate stable cooperator–defector coexistence. This mechanism may be important for maintaining public–goods cooperation and conflict in microbial pioneer species living on surfaces.     

Adult lipids associated with early life growth in traditional melanesian societies undergoing rapid modernization: A longitudinal study of the mid‐20th century

Both poor fetal development and accelerated post‐natal growth have been linked to adult dyslipidemias in many studies conducted in developed societies. It is not known, however, whether these relationships only characterize populations with typical Western diets or if they also may develop in groups at the early stages of a dietary transition. Our longitudinal study of traditional rural populations in the Southwest Pacific during a period of extremely rapid modernization in diet and life‐styles shows a nascent association between child growth retardation, subsequent growth acceleration, and adult lipid values in spite of a continuing prevalence of very low lipid levels. However, our results do not entirely conform to results from populations with “modern” diets. Outcome (i.e., young adult) cholesterol and triglyceride levels are more consistently related to initial measures of body fat and growth in body fat measures than with stature, while outcome apo A‐1 is more consistently related to initial stature or stature growth than to measures of body fat. We suggest this may reflect a pattern characteristic of the initial stages of “modernization” associated with dietary change, with stronger and more pervasive relationships emerging only later as populations complete the dietary transition. Am J Phys Anthropol 153:551–558, 2014. © 2013 Wiley Periodicals, Inc.     

An iterative approach from the standpoint of the additive hypothesis to the dendrogram problem posed by molecular data sets

The problem of constructing a dendrogram depicting phylogenetic relationships for a collection of contemporary species is considered. An approach was developed based on the additive hypothesis in which each “length” between two species can be described by the shortest sum of lengths for the individual links on the dendrogram topology which connect the two species. The additive hypothesis holds equally well if the dendro gram is replaced by its corresponding (rootless) network. Network topologies are defined set theoretically in terms of the initial, contemporary species, and a coefficient is defined for each point of any conceivable network. It is proved mathematically that each point of an additive network gives a coefficient value of zero, whereas each point not belonging to an additive network gives a coefficient value greater than zero. This suggests an iterative procedure in which “false” network points are replaced by “true” ones, or more generally in which “very false” network points are replaced by “nearly true” ones. The first procedure follows from the mathematical proof and the second is confirmed by simulation. Since most real data sets are not additive in the strict sense, a real data example was presented in which the iterative procedure produced a plausible network topology.     

SPERM COMPETITION AND THE EVOLUTION OF SEMINAL FLUID COMPOSITION

Male ejaculates include large amounts of seminal fluid proteins (Sfps) that influence male sperm competitive success. In spite of their diverse proximate functions, Sfps involved in sperm competition increase male fitness in one of three ways: (1) “avoidance” proteins help males avoid sperm competition, (2) “defense” proteins help males defend their sperm from displacement by the female's subsequent mate, and (3) “offense” proteins aid males in displacing sperm of preceding males. Here, we present a population genetic model of the evolution of allocation of finite resources by males to the three kinds of Sfps. We analyze the influence of relative efficiencies of different Sfps, of plasticity in resource allocation, and of differences in viability costs of Sfps. We find that in absence of plasticity or different viability costs, equal investment in defense and offense Sfps evolves, irrespective of their relative efficiency. In all cases, males evolve to invest more in avoidance when avoidance proteins are increasingly efficient, and when offense is more efficient than defense. Differences in viability costs result in lower investment in costly proteins, whereas plasticity has complex effects, influencing both the optimal seminal fluid composition and maintenance of variation in investment in these proteins across populations.     

Analysis of stability of different regimes of heart rate dynamics by computer modeling

Computer modeling revealed the following three regimes of heart rate dynamics: linear dynamics, “1st degree chaos,” and “2nd degree chaos.” This study investigated a stability of these regimes with respect to changes in initial conditions. The results show that the greatest stability is notable for the linear regime. For this regime small errors in values of initial conditions can not sharply change the initial dynamics of RR intervals. Both nonlinear regimes of heart rate dynamics are unstable, and a degree of instability of regime “2nd degree chaos” is higher in comparison with regime “1st degree chaos.” The results of computer modeling are in agreement with experimental data pointing to the existence of a relationship between the degree of heart rate irregularity and cardiac electrical stability.     

Rapid electroelution of nucleic acids from agarose and acrylamide gels

The alkaline/filter DNA elution technique measures single-strand DNA breaks in mammalian cells based on the DNA molecular weight dependent retention of the macromolecule on 2-μm-pore-size filters. Described here is a modification of the technique which uses [³H]thymidine-labeled DNA of γ-irradiated cells as an internal reference. Thus, an increased precision is obtained in the assessment of this type of DNA damage at biologically significant radiation doses (i.e., where cell survival occurs). The measure of DNA damage is based on the actual initial DNA elution rate, i.e., arithmetic ratio of the elution of “test” DNA (i.e., ¹⁴C-labeled DNA) relative to the elution of “reference” DNA (i.e., ³H-labeled DNA). The repair of this damage on postirradiation incubation of the cells is detected as a decrease in the rate of “test” DNA cluted relative to “reference” DNA from unincubated cells. For Chinese hamster V79–171 cells irradiated with 5 Gy (500 rads), repair can be resolved into two first-order processes having rate constants (at 24°C) of ～0.190 and ～0.017 min^?1.     

Subjective Distress Associated with Adult ADHD: evaluation of a new self-report

The current study aims at documenting the psychometric properties of the Subjective Distress Associated with Adult ADHD-Self-Report (SDAAA-SR), a newly developed instrument for the assessment of psychological suffering in ADHD adults. The SDAAA-SR was administered to 247 students and 142 ADHD adults. Factor structure, internal consistency, test–retest reliability, convergent validity and discriminant validity were assessed. Sensitivity to change was examined in a subsample of 25 ADHD patients who participated in a 1-year therapy. The initial pool of 62 items was reduced to 33 items distributed in a three-component structure. Internal consistency was excellent for the “distress due to inattention/disorganization” subscale and good for the “distress due to hyperactivity/impulsivity” and “distress due to self-esteem deficit” subscales. Test–retest reliability in a subsample of 98 students was substantial for all three subscales. ADHD patients scored significantly higher than students on distress due to “inattention/disorganization” and “hyperactivity/impulsivity,” but no difference was observed for “self-esteem deficit.” The components “inattention/disorganization” and “hyperactivity/impulsivity” displayed moderate to large correlations with the corresponding dimensions of the Adult Self-Report Scale for ADHD (ASRS-V1.1). Distress due to “inattention/disorganization” and “self-esteem deficit” was significantly associated with lower satisfaction with social behaviors (QFS, social functioning questionnaire) and quality of life (WHOQOL-BREF). Distress due to “inattention/disorganization” and “self-esteem deficit” significantly decreased after a 1-year therapy. The SDAAA-SR represents a reliable and valid measure of adult ADHD-associated distress, an important but often undocumented parameter in the clinical setting. Its use as an outcome variable in psychological interventions deserves further investigation.     

Colony Structure in Flustra foliacea (Linnaeus) (Bryozoa,Chéilostomata)

Encrusting forms presumably represent the original mode of growth in the bryozoans. They usually exhibit a relatively low degree of colony integration. The numerous different erect colony types, certainly independently derived from this stage, show a higher degree of integration. Eventually forms arise with a strict pattern only little influenced by the environment. The Flustra foliacea colony holds an intermediate position in this respect. It forms an initial crust on a foreign substratum such as rock. The crust forms marginal lobes. The lobes collide two and two. The two components of each collision then rise back to back, owing to lack of space, into bilaminar fronds. The two zooid layers composing these erect branches and mutually encrusting the “auto-substratum” of their respective basal walls, grow much more rapidly than the initial crust on the “heterosubstratum” of the rock to finally comprise more than 95 % of the colony volume. The different rate of growth on “auto-” and “heterosubstratum” respectively is interpreted as indicating a preference for the “autosubstratum” and as the main force in the formation of erect branches. The Fl. foliacea case indicates one of the pathways from encrusting to erect colonies in the bryozoans. It is probably valid for at least some of the erect bilaminar colonies appearing in different parts of the bryozoan system.