Proceedings of the 6th conference on the neurobiology of learning and memory. Brain and memory: from genes to behavior. Some historical background of topics in this conference

The fungal cell wall, though phylogenetically variable, acts universally as a potent barrier to probing intracellular structures. Thus, the use of high-molecular-weight probes such as antibodies and lectins has proven a formidable challenge. We have devised a preparative method for use with various affinity probes that can be applied to a broad spectrum of filamentous fungal species and used for imaging whole cells. In this study, confocal imaging of whole-mount fungal hyphae after freeze substitution, methacrylate embedment/de-embedment, and infiltration with affinity probes has yielded remarkably improved renderings of the three-dimensional distribution of both microtubules (using antibodies against both alpha- and beta-tubulin) and concanavalin A binding sites. Using this protocol we have been able to document: (1) the three-dimensional distribution of microtubules in all regions of hyphae, (2) the presence of apparent foci for cytoplasmic microtubules, (3) persistent cytoplasmic microtubules during mitosis, and (4) a three-dimensional view of many compartments of the endomembrane system including Golgi-equivalent organelles and apical vesicles. The last result represents the first direct confirmation of apical vesicles comprising the Spitzenk?rper.     

A search for relations between brain chemistry and behavior.

This report summarizes the results of unpublished and widely scattered published studies on the inter-relationship of acetylcholine (ACh) and cholinesterase (ChE) on the adaptive behavior of rats. 2 early hypotheses, now rejected, generated several findings of considerable interest leading to the development of a 3rd hypothesis which has so far stood the test of empirical verification. A brief summary of current and projected studies are included. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Obituary: Paul Fraisse (1911–1996).

Memorializes Paul Fraisse whose main areas of research were the perception of time and duration; perception of rhythms, and rhythms in behavior; aspects of language, in particular attempts to understand why naming an object takes more time than reading the name of the object; and memory for words and for pictures. From the 1940s through the 1970s, Fraisse explored different approaches to the psychology of time: chronobiology, psychophysics, the Piagetian approach to the acquisition of the notion of time, philosophical approaches, and the application of these viewpoints to the perception of rhythm in music and in poetry. Fraisse's long academic career was spent entirely in Paris, where he occupied many major positions and where he struggled to obtain an adequate place for psychology in the university and scientific sphere in France. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Object interactions in juvenile rats (Rattus norvegicus): Effects of different experiential histories.

Examined the spontaneous ways in which an individual rat gathers information about its environment and the extent to which this information-gathering strategy is modified by experience. 30 male rats of the Berkeley S? strain were placed at weaning in enriched, group-housed, or impoverished conditions. After 30 days, they were placed individually in a dimly illuminated arena with several objects and videotaped for 10-min periods on 2 successive days. Analysis of the videotaped records showed no significant differences among the groups in locomotion, investigation of the arena, defecation, grooming, or total amount of object contact, but it showed significant differences in behaviors used during interactions with objects. Ss from the enriched condition showed significantly more diversity of behavior related to those objects that were small enough to be moved, without intergroup differences in amount of object contact. These experience-dependent changes in strategies for exploration may have widespread functional consequences. The procedure for videotape analysis presented here may be useful in studying many problems of animal behavior. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Uncooled high-temperature (130/spl deg/C) operation of InGaAs-GaAs multiple quantum-well lasers at 20 Gb/s

Short-haul fiber-optic communication systems require high-speed semiconductor lasers that can operate uncooled over a wide temperature range. In this letter, we describe high-speed short-cavity InGaAs-GaAs multiple-quantum-well lasers operating at 1.1-/spl mu/m wavelength. The Fabry-Perot lasers were fabricated in a triple-mesa geometry suitable for on-wafer probing. With 3/spl times/200 /spl mu/m/sup 2/ ridge-waveguide lasers, which showed the best compromise between high-temperature and high-speed performance, a 3-dB modulation bandwidth of 14.5 GHz at 130/spl deg/C was achieved. Uncooled 20-Gb/s operation of these lasers is presented over a wide-temperature range from 25/spl deg/C to 130/spl deg/C without automatic power control.     

Enhanced maintenance and retroviral transduction of primitive hematopoietic progenitor cells using a novel three-dimensional culture system

Current techniques for the in vitro maintenance of hematopoietic stem cells often lead to loss of pluripotency. Overcoming the technical difficulties that result in alterations in stem cells in vitro has important implications for areas of basic science and clinical medicine such as cell expansion, bone marrow transplantation and gene therapy. Recent insights into hematopoietic stem cell biology have demonstrated that the three-dimensional architecture of the culture environment may influence the maintenance of stem cell pluripotency in vitro. An intriguing hypothesis is that the utilization of three-dimensional culture systems may improve the maintenance and manipulation of these cells in vitro. We report that a novel, three-dimensional, tantalum-coated porous biomaterial (TCPB) may be employed effectively as a hematopoietic progenitor cell culture device that offers distinct advantages over conventional culture systems. Specifically, we demonstrate that the use of TCPB for culturing hematopoietic progenitor cells in the absence of exogenous cytokines results in enhanced hematopoietic progenitor cell survival, improved maintenance of the immature CD34+/38- phenotype, and improved retroviral transduction of CD34+ cells and long-term culture initiating cells (LTCIC), without compromising multipotency, as compared with cultures in plastic dishes or bone marrow stroma. These findings suggest that this three-dimensional culture system may be useful in advancing the in vitro culture and transduction of hematopoietic stem and progenitor cells.     

alpha factor improvements in high-speed p doped In/sub 0.35/Ga /sub 0.65/As/GaAs MQW lasers

The authors investigate experimentally for the first time the improvements in the linewidth enhancement factor, alpha , resulting from simultaneous addition of strain and p-doping in high-speed GaAs-based multiquantum well lasers. The alpha factor is determined from measured changes in both gain and refractive index as a function of CW bias current, yielding alpha 3.1 and 1.4 at the threshold lasing wavelength for unstrained GaAs/Al/sub 0.25/Ga/sub 0.75/As and p-doped strained In/sub 0.35/Ga/sub 0.65/As/GaAs devices, respectively.<>     

The way it was: Remembering David Shakow.

Comments on the obituary for David Shakow (see record 2005-08120-013) and further eulogizes him for his dedication and accomplishments. The author focuses primarily on the twelve years during which Shakow worked at the Worcester State Hospital (WSH). (PsycINFO Database Record (c) 2010 APA, all rights reserved)