The effect of pollen source on seed traits and dispersability in the heterocarpic annual Crepis sancta

不同花粉来源对一年生植物种子性状和扩散能力的影响与扩散有关的性状进化和表达与其他生活史功能交织在一起,并在各种生理约束条件下表现出 来。这种关系可以在近交水平和扩散性之间得到预测,而且在解剖学和个体发育上联系在一起,从而使 某个选择压力可能影响另外的一个。虽然近交对生殖成功和扩散策略的影响都引起了广泛关注,但只有 少数研究同时考虑了这两者。此外,此类研究通常依赖于繁殖和扩散的表示：使用自交与异源杂交表示繁殖水平,使用扩散比表示扩散策略。本研究利用菊科Crepis sancta的授粉实验,以两种不同的方式扩展 繁殖和扩散的二分表示法。首先,我们使用授粉处理来表示一种统一连续体,即从亲缘授粉的自交到距离较远的邻居授粉。其次,我们不仅测量了繁殖成功率和扩散比,还测量了一整套连续的与形态和扩散相关的性状。研究结果显示,头状花序的比例,以及扩散的和非扩散的瘦果在自花传粉处理中都显著低于异源杂交处理。尽管自花授粉的植物很少产生不扩散的种子,但花粉来源对扩散比的影响统计上不显著。瘦果的生物量随亲本植物之间的距离增加而增加,但冠毛宽度没有增加,从而导致授粉对下落速度的影响不显着。总之,花粉来源主要影响与生殖产量有关的性状,但对主要与扩散有关的性状没有显著影响。繁殖和扩散性状对花粉来源变化响应的这种差异表明,与扩散有关的选择可能很弱和/或被其他因素所掩盖。     

Genome sequence of the pattern-forming social bacterium Paenibacillus dendritiformis C454 chiral morphotype

Paenibacillus dendritiformis is a Gram-positive, soil-dwelling, spore-forming social microorganism. An intriguing collective faculty of this strain is manifested by its ability to switch between different morphotypes, such as the branching (T) and the chiral (C) morphotypes. Here we report the 6.3-Mb draft genome sequence of the P. dendritiformis C454 chiral morphotype.     

Octopamine Neuromodulation Regulates Gr32a-Linked Aggression and Courtship Pathways in Drosophila Males

Chemosensory pheromonal information regulates aggression and reproduction in many species, but how pheromonal signals are transduced to reliably produce behavior is not well understood. Here we demonstrate that the pheromonal signals detected by Gr32a-expressing chemosensory neurons to enhance male aggression are filtered through octopamine (OA, invertebrate equivalent of norepinephrine) neurons. Using behavioral assays, we find males lacking both octopamine and Gr32a gustatory receptors exhibit parallel delays in the onset of aggression and reductions in aggression. Physiological and anatomical experiments identify Gr32a to octopamine neuron synaptic and functional connections in the suboesophageal ganglion. Refining the Gr32a-expressing population indicates that mouth Gr32a neurons promote male aggression and form synaptic contacts with OA neurons. By restricting the monoamine neuron target population, we show that three previously identified OA-Fru^M neurons involved in behavioral choice are among the Gr32a-OA connections. Our findings demonstrate that octopaminergic neuromodulatory neurons function as early as a second-order step in this chemosensory-driven male social behavior pathway.     

Skin Vaccination against Rotavirus Using Microneedles: Proof of Concept in Gnotobiotic Piglets

Live-attenuated oral rotavirus (RV) vaccines have lower efficacy in low income countries, and additionally are associated with a rare but severe adverse event, intussusception. We have been pursuing the development of an inactivated rotavirus vaccine (IRV) using the human rotavirus strain CDC-9 (G1P[8]) through parenteral immunization and previously demonstrated dose sparing and enhanced immunogenicity of intradermal (ID) unadjuvanted IRV using a coated microneedle patch in comparison with intramuscular (IM) administration in mice. The aim of this study was to evaluate the immune response and protection against RV infection and diarrhea conferred by the administration of the ID unadjuvanted IRV using the microneedle device MicronJet600^® in neonatal gnotobiotic (Gn) piglets challenged with virulent Wa G1P[8] human RV. Three doses of 5 μg IRV when administered intradermally and 5 μg IRV formulated with aluminum hydroxide [Al(OH)₃] when administered intramuscularly induced comparable rotavirus-specific antibody titers of IgA, IgG, IgG avidity index and neutralizing activity in sera of neonatal piglets. Both IRV vaccination regimens protected against RV antigen shedding in stools, and reduced the cumulative diarrhea scores in the piglets. This study demonstrated that the ID and IM administrations of IRV are immunogenic and protective against RV-induced diarrhea in neonatal piglets. Our findings highlight the potential value of an adjuvant sparing effect of the IRV ID delivery route.     

Mechanisms of Neural and Behavioral Dysfunction in Alzheimer’s Disease

This review critically examines progress in understanding the link between Alzheimer’s disease (AD) molecular pathogenesis and behavior, with an emphasis on the impact of amyloid-β. We present the argument that the AD research field requires more multifaceted analyses into the impacts of Alzheimer’s pathogenesis which combine simultaneous molecular-, circuit-, and behavior-level approaches. Supporting this argument is a review of particular research utilizing similar, “systems-level” methods in mouse models of AD. Related to this, a critique of common physiological and behavioral models is made—highlighting the likely usefulness of more refined and specific tools in understanding the relationship between candidate molecular pathologies and behavioral dysfunction. Finally, we propose challenges for future research which, if met, may greatly extend our current understanding of how AD molecular pathology impacts neural network function and behavior and possibly may lead to refinements in disease therapeutics.     

Insulin-producing cells generated from dedifferentiated human pancreatic beta cells expanded in vitro

Background

Expansion of beta cells from the limited number of adult human islet donors is an attractive prospect for increasing cell availability for cell therapy of diabetes. However, attempts at expanding human islet cells in tissue culture result in loss of beta-cell phenotype. Using a lineage-tracing approach we provided evidence for massive proliferation of beta-cell-derived (BCD) cells within these cultures. Expansion involves dedifferentiation resembling epithelial-mesenchymal transition (EMT). Epigenetic analyses indicate that key beta-cell genes maintain open chromatin structure in expanded BCD cells, although they are not transcribed. Here we investigated whether BCD cells can be redifferentiated into beta-like cells.

Methodology/Principal Finding

Redifferentiation conditions were screened by following activation of an insulin-DsRed2 reporter gene. Redifferentiated cells were characterized for gene expression, insulin content and secretion assays, and presence of secretory vesicles by electron microscopy. BCD cells were induced to redifferentiate by a combination of soluble factors. The redifferentiated cells expressed beta-cell genes, stored insulin in typical secretory vesicles, and released it in response to glucose. The redifferentiation process involved mesenchymal-epithelial transition, as judged by changes in gene expression. Moreover, inhibition of the EMT effector SLUG (SNAI2) using shRNA resulted in stimulation of redifferentiation. Lineage-traced cells also gave rise at a low rate to cells expressing other islet hormones, suggesting transition of BCD cells through an islet progenitor-like stage during redifferentiation.

Conclusions/Significance

These findings demonstrate for the first time that expanded dedifferentiated beta cells can be induced to redifferentiate in culture. The findings suggest that ex-vivo expansion of adult human islet cells is a promising approach for generation of insulin-producing cells for transplantation, as well as basic research, toxicology studies, and drug screening.     

To strike or not to strike? House-staff attitudes and behaviors during a hospital work action.

Work actions by house staff are an infrequent response to sometimes difficult working conditions, but they can have a notable effect on institutional cohesiveness and represent a challenge to traditional notions of medical ethics. To determine the extent of participation in a hospital-wide doctors'' strike and factors associated with participation, we surveyed 432 house officers at a university-affiliated public hospital where a contract dispute had recently led to a 4-day work action. Of 257 respondents, 69% approved of the strike and 50% participated in it. Both strikers and nonstrikers agreed that quality of care and specific contract issues were important precipitants of the event. By logistic regression, factors independently associated with strike participation (P less than .05) included being unmarried, training in internal medicine or psychiatry, being in earlier stages of training, being assigned to an outpatient service at the time of the strike, holding a favorable view of physician activism, and perceiving nurses, faculty, peers, and the public to have favored the strike. These associations may provide a basis for understanding the individual and social determinants of house-staff strike activity.     

Superinduction of human interleukin-2 messenger RNA by inhibitors of translation

Stimulation of human lymphocytes with phytohemagglutinin results in the induction of messenger RNA encoding interleukin-2 (IL-2), a lymphokine possessing immuno-regulatory properties. We have previously demonstrated a dramatic superinduction of the formation of IL-2 and of biologically active IL-2 mRNA in the presence of cycloheximide, an inhibitor of translation. These findings suggested the involvement of a labile protein repressor in the regulation of human IL-2 gene expression. Here, we show a commensurate superinduction of IL-2 mRNA sequences by three additional inhibitors of protein synthesis with distinct modes of action: T-2 toxin, pactamycin, and sparsomycin. These results strengthen the concept that a labile protein controls the formation of mature IL-2 mRNA. They tend to eliminate the possibility that the superinduction phenomenon observed in the presence of cycloheximide is due to its action on a process other than translation.     

LOCALIZATION OF THE SITES OF γ-AMINOBUTYRIC ACID (GABA) UPTAKE IN LOBSTER NERVE-MUSCLE PREPARATIONS

The principal sites of γ-aminobutyric acid (GABA) uptake in lobster nerve-muscle preparations have been determined with radioautographic techniques after binding of the amino acid to proteins by aldehyde fixation. Semiquantitative studies showed that about 30% of the radioactive GABA taken into the tissue was bound to protein by fixation. Both light and electron micrographs showed dense accumulations of label over Schwann and connective tissue cell cytoplasm; muscle was lightly labeled, but axons and terminals were almost devoid of label. The possible role of Schwann and connective tissue cells in the inactivation of GABA released from inhibitory axons is discussed.