Reflection on the Queensland Brain Institute's growth and direction

The article details how Professor Bartlett realised his vision of creating a unique scientific environment in which to discover the fundamental mechanisms that regulate brain functions like learning and memory through the formation of the Queensland Brain Institute (QBI). The establishment of the QBI came about through the prescient support of philanthropist Chuck Feeney, Queensland Premiers Beattie and Bligh and The University of Queensland Vice Chancellor John Hay. This underpinned the ability to recruit a team of outstanding neuroscientists from around the world and around Australia and ensured the QBI was equipped with state of the art technologies. Although, the QBI has been in its new building for three years, the success of the venture already is evident by its peerless grant and fellowship success, and its output of highly cited publications positioning it as a pre-eminent neuroscience research institute within the Asia-Pacific region

A novel fluorescent reporter CDy1 enriches for neural stem cells derived from the murine brain

Neurogenesis occurs continuously in two brain regions of adult mammals, underpinned by a pool of resident neural stem cells (NSCs) that can differentiate into all neural cell types. To advance our understanding of NSC function and to develop therapeutic and diagnostic approaches, it is important to accurately identify and enrich for NSCs. There are no definitive markers for the identification and enrichment of NSCs present in the mouse brain. Recently, a fluorescent rosamine dye, CDy1, has been identified as a label for pluripotency in cultured human embryonic and induced pluripotent stem cells. As similar cellular characteristics may enable the uptake and retention of CDy1 by other stem cell populations, we hypothesized that this dye may also enrich for primary NSCs from the mouse brain. Because the subventricular zone (SVZ) and the hippocampus represent brain regions that are highly enriched for NSCs in adult mammals, we sampled cells from these areas to test this hypothesis. These experiments revealed that CDy1 staining indeed allows for enrichment and selection of all neurosphere-forming cells from both the SVZ and the hippocampus. We next examined the effectiveness of CDy1 to select for NSCs derived from the SVZ of aged animals, where the total pool of NSCs present is significantly lower than in young animals. We found that CDy1 effectively labels the NSCs in adult and aged animals as assessed by the neurosphere assay and reflects the numbers of NSCs present in aged animals. CDy1, therefore, appears to be a novel marker for enrichment of NSCs in primary brain tissue preparations

Amyotrophic lateral sclerosis genetic studies: from genome-wide association mapping to genome sequencing

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease of obscure etiology. Multiple genetic studies have been conducted to advance our understanding of the disease, employing a variety of techniques such as linkage mapping in families, to genome-wide association studies and sequencing based approaches such as whole exome sequencing and whole genome sequencing and a few epigenetic analyses. While major progress has been made, the majority of the genetic variation involved in ALS is yet to be undefined. The optimal study designs to investigate ALS depend on the genetic model for the disease, and it is likely that different approaches will be required to map genes involved in familial and sporadic disease. The potential approaches and their strengths and weaknesses are discussed

Impact of Socioeconomic Factors on Florida Consumers\u27 Perceptions on Use of Chemical in Locally or Regionally Produced Livestock Products

Abstract The use of chemicals in livestock production has been an issue for consumers for several decades. This study, therefore, assessed the impact of socioeconomic factors on Florida consumers’ perceptions on the use of chemicals in locally or regionally produced livestock products. Data were collected from a sample of 404 participants from several Florida counties and were analyzed using descriptive statistics and ordinal logistic analysis. Most of the respondents were of the opinion that using chemicals in locally or regionally produced and sold beef or goat meat was a serious or somewhat serious hazard. The ordinal logistic regression results showed that several socioeconomic factors, such as household size, gender, age, and education had significant effects on pesticide residues; antibiotics; artificial fertilizers; additives and preservatives, and artificial coloring. It was recommended that producers and processors should minimize the use of chemicals in livestock products as this has both short- and long-term benefits. Keywords: Socioeconomic Factors, Chemicals, Consumer Perceptions, Locally or Regionally Produced, Livestock Product

Microglia modulate hippocampal neural precursor activity in response to exercise and aging

Exercise has been shown to positively augment adult hippocampal neurogenesis; however, the cellular and molecular pathways mediating this effect remain largely unknown. Previous studies have suggested that microglia may have the ability to differentially instruct neurogenesis in the adult brain. Here, we used transgenic Csf1r-GFP mice to investigate whether hippocampal microglia directly influence the activation of neural precursor cells. Our results revealed that an exercise-induced increase in neural precursor cell activity was mediated via endogenous microglia and abolished when these cells were selectively removed from hippocampal cultures. Conversely, microglia from the hippocampi of animals that had exercised were able to activate latent neural precursor cells when added to neurosphere preparations from sedentary mice. We also investigated the role of CX(3)CL1, a chemokine that is known to provide a more neuroprotective microglial phenotype. Intraparenchymal infusion of a blocking antibody against the CX(3)CL1 receptor, CX(3)CR1, but not control IgG, dramatically reduced the neurosphere formation frequency in mice that had exercised. While an increase in soluble CX(3)CL1 was observed following running, reduced levels of this chemokine were found in the aged brain. Lower levels of CX(3)CL1 with advancing age correlated with the natural decline in neural precursor cell activity, a state that could be partially alleviated through removal of microglia. These findings provide the first direct evidence that endogenous microglia can exert a dual and opposing influence on neural precursor cell activity within the hippocampus, and that signaling through the CX(3)CL1-CX(3)CR1 axis critically contributes toward this process

A light-front coupled-cluster method for the nonperturbative solution of quantum field theories

We propose a new method for the nonperturbative solution of quantum field theories and illustrate its use in the context of a light-front analog to the Greenberg--Schweber model. The method is based on light-front quantization and uses the exponential-operator technique of the many-body coupled-cluster method. The formulation produces an effective Hamiltonian eigenvalue problem in the valence Fock sector of the system of interest, combined with nonlinear integral equations to be solved for the functions that define the effective Hamiltonian. The method avoids the Fock-space truncations usually used in nonperturbative light-front Hamiltonian methods and, therefore, does not suffer from the spectator dependence, Fock-sector dependence, and uncanceled divergences caused by such truncations.Comment: 11 pages, 4 figures, RevTeX 4.1; expanded description of method and replaced QED with simpler model for illustratio

Nerve growth factor signaling through p75 induces apoptosis in Schwann cells via a Bcl-2-independent pathway

Apoptosis is involved in the regulation of Schwann cell numbers during normal development and after axonal damage, but the molecular regulation of Schwann cell death remains unknown. We have used stably transfected rat Schwann cell lines to study the potential roles of nerve growth factor (NGF), the antiapoptotic protein Bcl-2 and the cytokine response modifier A (CrmA) in modulating Schwann cell death in vitro. Bcl-2 inhibited Schwann cell apoptosis induced by survival factor withdrawal, whereas CrmA did not. In contrast, Bcl-2-transfected Schwann cells were susceptible to apoptosis in response to exogenous NGF, whereas CrmA-expressing cell lines were resistant. Demonstration of high levels of the low-affinity neurotrophin receptor p75 but not the high-affinity TrkA receptor on the Bcl-2-transfected cell lines suggested that the NGF-induced killing was mediated by p75. This was confirmed by resistance of Schwann cells isolated from p75 knockout mice to the NGF-induced cell death. Nerve growth factor also promoted the death of wild-type mouse and rat Schwann cells in the absence of survival factor withdrawal. Endogenous Bcl-2 mRNA was expressed by wild-type Schwann cells in all conditions that promoted survival but was downregulated to undetectable levels after survival factor withdrawal. In conclusion, our results demonstrate the existence of two separate pathways that expedite apoptosis in Schwann cells: a Bcl-2-blockable pathway initiated on loss of trophic support, and a Bcl-2-independent, CrmA-blockable pathway mediated via the p75 receptor

Latent stem and progenitor cells in the hippocampus are activated by neural excitation

The regulated production of neurons in the hippocampus throughout life underpins important brain functions such as learning and memory. Surprisingly, however, studies have so far failed to identify a resident hippocampal stem cell capable of providing the renewable source of these neurons. Here, we report that depolarizing levels of KCl produce a threefold increase in the number of neurospheres generated from the adult mouse hippocampus. Most interestingly, however, depolarizing levels of KCl led to the emergence of a small subpopulation of precursors (approximately eight per hippocampus) with the capacity to generate very large neurospheres (>250 µm in diameter). Many of these contained cells that displayed the cardinal properties of stem cells: multipotentiality and self-renewal. In contrast, the same conditions led to the opposite effect in the other main neurogenic region of the brain, the subventricular zone, in which neurosphere numbers decreased by ~40% in response to depolarizing levels of KCl. Most importantly, we also show that the latent hippocampal progenitor population can be activated in vivo in response to prolonged neural activity found in status epilepticus. This work provides the first direct evidence of a latent precursor and stem cell population in the adult hippocampus, which is able to be activated by neural activity. Because the latent population is also demonstrated to reside in the aged animal, defining the precise mechanisms that underlie its activation may provide a means to combat the cognitive deficits associated with a decline in neurogenesis

An Analysis of the Characteristics and Practices of Selected Florida Small Livestock Producers: A Focus on Economics and Marketing

Issues regarding economics and marketing are of importance to small livestock producers, who produce and sell locally or regionally. This study, thus, assessed the characteristics and practices of selected Florida small livestock producers, emphasizing economics and marketing. Data were collected from a convenience sample of seventy small producers from several Florida counties, and were analyzed using descriptive statistics, including chi-square tests. The findings showed that there were many more: full-time producers; producers with at least a two-year/technical degree, and producers with at, least, a $40,000 annual household income. Most had been farming more than fifteen years, on at least 50 acres, and had small herds. Furthermore, very few of them made profits; they mainly sold animals live on-farm or at the auction/stockyard, and many of them kept records. Chi-square tests showed that gender, age, education, and household income had statistically significant effects on selected marketing characteristics. The findings suggest that educational programs that emphasize economic and marketing issues should be taken into consideration when designing programs for small producers in the study area. Keywords: Livestock Producers, Small Producers, Characteristics and Practices, Economics and Marketin

The respiratory mechanics of the yacare caiman (Caiman yacare Daudine)

The structure and function of crocodilian lungs are unique compared to other reptiles. We examine the extent to which this, and the semi-aquatic lifestyle of crocodilians affect their respiratory mechanics. We measured changes in intratracheal pressure in adult and juvenile caiman (Caiman yacare) during static and dynamic lung volume changes. Respiratory mechanics of juvenile caiman were additionally measured while floating in water and submerged at 30°, 60°, and 90° to the water's surface. The static compliance of the juvenile pulmonary system (2.89±0.22 mL cmH2O 100g−1) was greater than that of adults (1.2±0.41 ml cmH2O 100g−1), suggesting that the system stiffens as the body wall becomes more muscular and keratinized in adults. For both age groups, the lungs were much more compliant than the body wall, offering little resistance to air flow (15.35 and 4.25 for lungs, versus 3.39 and 1.67 mL cmH2O 100g−1 for body wall, in juveniles and adults respectively). Whole system dynamic mechanics decreased with increasing ventilation frequency (fR), but was unaffected by changes in tidal volume (VT). The vast majority of work of breathing was required to overcome elastic forces, however work to overcome resistive forces increased proportionally with fR. Work of breathing was higher in juvenile caiman submerged in water at 90°, due to an increase in work to overcome both elastic and flow resistive forces. The lowest power of breathing was found to occur at high fR and low VT for any given minute ventilation (V̇E) in caiman of all ages