The role of candidate transport proteins in ß-cell long-chain fatty acid uptake: Where are we now?

Type 2 diabetes (T2D) in humans is typically preceded by elevated levels of circulatory long-chain free fatty acids (LC-FFA). These excess LC-FFA are widely thought to be taken up by pancreatic ß-cells, contributing to their dysfunction and death during the development of T2D; a process that has been termed lipotoxicity. Depending on their degree of saturation and carbon chain length, LC-FFA can exert different effects on pancreatic ß-cells viability and function in vitro. Long-chain saturated fatty acids (LC-SFA) are thought to be toxic, whereas monounsaturated fatty acids are not and may even offer protection against the toxic effects of LC-SFAs. However, the mechanism of LC-FFA uptake into pancreatic ß-cells is poorly understood, partly because it has been an understudied area of research. Determining how LC-FFA are taken up into ß-cells is crucial for later formulation of therapies to prevent potential cellular overload of LC-FFA, thereby slowing the onset of T2D. In this work, we detail more than 40 years of literature investigating the role of membrane-associated transport proteins in LC-FFA uptake. By focussing on what is known in other cell types, we highlight where we can extrapolate our current understanding of protein-mediated transport to ß-cells and uncover where further understanding is required.

The Case for the Target of Rapamycin Pathway as a Candidate Circadian Oscillator.

The molecular mechanisms that drive circadian (24 h) rhythmicity have been investigated for many decades, but we still do not have a complete picture of eukaryotic circadian systems. Although the transcription/translation feedback loop (TTFL) model has been the primary focus of research, there are many examples of circadian rhythms that persist when TTFLs are not functioning, and we lack any good candidates for the non-TTFL oscillators driving these rhythms. In this hypothesis-driven review, the author brings together several lines of evidence pointing towards the Target of Rapamycin (TOR) signalling pathway as a good candidate for a non-TTFL oscillator. TOR is a ubiquitous regulator of metabolism in eukaryotes and recent focus in circadian research on connections between metabolism and rhythms makes TOR an attractive candidate oscillator. In this paper, the evidence for a role for TOR in regulating rhythmicity is reviewed, and the advantages of TOR as a potential oscillator are discussed. Evidence for extensive feedback regulation of TOR provides potential mechanisms for a TOR-driven oscillator. Comparison with ultradian yeast metabolic cycles provides an example of a potential TOR-driven self-sustained oscillation. Unanswered questions and problems to be addressed by future research are discussed.

The Healthcare Environment Survey: A multicountry psychometric evaluation of nurses' job satisfaction.

AIM: To evaluate the properties of a reduced-item Healthcare Environment Survey measuring nurses' job satisfaction across eight countries. BACKGROUND: There is currently no rigorously tested international measure of nurses' job satisfaction that can be used internationally to improve the nurse work environment. METHODS: Nursing staff from 11 hospitals in eight countries participated in this study. The original 57-item, 11-facet Healthcare Environment Survey was evaluated for reliability, validity, and measurement invariance: Cronbach's alpha was used to test for reliability; construct, discriminate, and convergent testing were used to test validity; and invariance testing including configural, metric, and scalar tests were used to study measurement invariance between the countries. RESULTS: 2,046 nursing staff completed the survey. Reliability was established for all six subscales and the combined composite score. Both validity and measurement invariance were supported in every test conducted. An excellent model fit was found for the final 19-item, 6-facet Healthcare Environment Survey that explained 82% of the variance of nurses' job satisfaction. CONCLUSIONS: Findings suggest the instrument is an efficient measure of nurses' job satisfaction across multiple countries. Longitudinal testing for invariance will be needed to ensure the model remains a good fit. Testing more countries will also verify model fit. IMPLICATIONS FOR NURSING: The instrument can be used to measure nurse job satisfaction globally. IMPLICATIONS FOR NURSING POLICY: The instrument can be used to assess interventions to improve the social (patient, unit manager, and coworker) and technical (professional rewards, autonomy, and professional growth) aspects of nurse job satisfaction.

Early Medical Students' Experiences as System Navigators: Results of a Qualitative Study.

PURPOSE: To explore how early meaningful experiential learning in community settings impacted medical students' application of systems thinking, their perceptions of systems navigation, and their professional identity as health system change agents. METHODS: Following an immersive Health Systems Science course, first-year medical students partnered with veterans or newly arrived refugee families and served as health system patient navigators embedded within primary care teams for a year. Across two cohorts, fifty-six students participated in the elective. Three voluntary focus groups were conducted each year for a total of six groups with 50 patient navigator students. Inductive content analysis of focus group transcripts was conducted. RESULTS: Qualitative analysis produced three major themes: program impact on students, student impact on patients, and student perceptions of the role of healthcare providers. Students reported a rich understanding of social determinants of health. By improving patient awareness of health and well-being, building capacity to understand medical issues, and increasing medication adherence through teaching, students recognized their impact on patient care. The importance of interprofessional collaboration with social workers also emerged and helped shape students' understanding of how they as physicians are part of a coordinated team working toward better patient care. CONCLUSION: The Case Western Reserve University WR2 curriculum teaches students how to address complex determinants of health and how to consider their role in dynamic health systems. This study highlights rich themes that emerged from students as they recognized the context that creates health for both individuals and communities. It underscores the role of such experiences in reinforcing systems thinking and development of change agency, both contributing to their professional identity formation as physicians.

Proteomic analysis of dietary restriction in yeast reveals a role for Hsp26 in replicative lifespan extension.

Dietary restriction (DR) has been shown to increase lifespan in organisms ranging from yeast to mammals. This suggests that the underlying mechanisms may be evolutionarily conserved. Indeed, upstream signalling pathways, such as TOR, are strongly linked to DR-induced longevity in various organisms. However, the downstream effector proteins that ultimately mediate lifespan extension are less clear. To shed light on this, we used a proteomic approach on budding yeast. Our reasoning was that analysis of proteome-wide changes in response to DR might enable the identification of proteins that mediate its physiological effects, including replicative lifespan extension. Of over 2500 proteins we identified by liquid chromatography-mass spectrometry, 183 were significantly altered in expression by at least 3-fold in response to DR. Most of these proteins were mitochondrial and/or had clear links to respiration and metabolism. Indeed, direct analysis of oxygen consumption confirmed that mitochondrial respiration was increased several-fold in response to DR. In addition, several key proteins involved in mating, including Ste2 and Ste6, were down-regulated by DR. Consistent with this, shmoo formation in response to α-factor pheromone was reduced by DR, thus confirming the inhibitory effect of DR on yeast mating. Finally, we found that Hsp26, a member of the conserved small heat shock protein (sHSP) family, was up-regulated by DR and that overexpression of Hsp26 extended yeast replicative lifespan. As overexpression of sHSPs in Caenorhabditis elegans and Drosophila has previously been shown to extend lifespan, our data on yeast Hsp26 suggest that sHSPs may be universally conserved effectors of longevity.

The Effect of Helium Ion Radiation on the Material Properties of Bone.

Ionizing radiation, from both space and radiation therapy, is known to affect bone health. While there have been studies investigating changes in bone density and microstructure from radiation exposure, the effects of radiation on material properties are unknown. The current study addresses this gap by assessing bone material property changes in rats exposed to helium-4 radiation through spherical micro-indentation. Rats were exposed to a single dose of 0, 5, and 25 cGy whole body helium-4 radiation. Animals were euthanized at 7, 30, 90, or 180-days after exposure. Spherical micro-indentation was performed on axial cross sections of the femur cortical bone to determine instantaneous and relaxed shear moduli. At 90-days after exposure, the 25 cGy exposure caused a significant decline in shear modulus compared to control and 5 cGy groups. The instantaneous modulus decreased 33% and the relaxed modulus decreased 32% as compared to the sham group. This decline was followed by a recovery of both moduli, which was observed by 180-days after exposure; at 180 days, the moduli were no longer statistically different from those at 7 or 30 days. The observed decrease at 90 days, followed by recovery to baseline levels, can be attributed to the biological mechanisms involved in bone formation that were affected by radiation, bone turnover, and systemic changes in hormones due to radiation exposure. Continued assessment of the mechanisms that drive such a response in material properties may enable identification of pathways for therapeutic countermeasures against radiation exposure.

A component of the TOR (Target Of Rapamycin) nutrient-sensing pathway plays a role in circadian rhythmicity in Neurospora crassa.

The TOR (Target of Rapamycin) pathway is a highly-conserved signaling pathway in eukaryotes that regulates cellular growth and stress responses. The cellular response to amino acids or carbon sources such as glucose requires anchoring of the TOR kinase complex to the lysosomal/vacuolar membrane by the Ragulator (mammals) or EGO (yeast) protein complex. Here we report a connection between the TOR pathway and circadian (daily) rhythmicity. The molecular mechanism of circadian rhythmicity in all eukaryotes has long been thought to be transcription/translation feedback loops (TTFLs). In the model eukaryote Neurospora crassa, a TTFL including FRQ (frequency) and WCC (white collar complex) has been intensively studied. However, it is also well-known that rhythmicity can be seen in the absence of TTFL functioning. We previously isolated uv90 as a mutation that compromises FRQ-less rhythms and also damps the circadian oscillator when FRQ is present. We have now mapped the uv90 gene and identified it as NCU05950, homologous to the TOR pathway proteins EGO1 (yeast) and LAMTOR1 (mammals), and we have named the N. crassa protein VTA (vacuolar TOR-associated protein). The protein is anchored to the outer vacuolar membrane and deletion of putative acylation sites destroys this localization as well as the protein's function in rhythmicity. A deletion of VTA is compromised in its growth responses to amino acids and glucose. We conclude that a key protein in the complex that anchors TOR to the vacuole plays a role in maintaining circadian (daily) rhythmicity. Our results establish a connection between the TOR pathway and circadian rhythms and point towards a network integrating metabolism and the circadian system.

Disordered directional brain network interactions during learning dynamics in schizophrenia revealed by multivariate autoregressive models.

Directional network interactions underpin normative brain function in key domains including associative learning. Schizophrenia (SCZ) is characterized by altered learning dynamics, yet dysfunctional directional functional connectivity (dFC) evoked during learning is rarely assessed. Here, nonlinear learning dynamics were induced using a paradigm alternating between conditions (Encoding and Retrieval). Evoked fMRI time series data were modeled using multivariate autoregressive (MVAR) models, to discover dysfunctional direction interactions between brain network constituents during learning stages (Early vs. Late), and conditions. A functionally derived subnetwork of coactivated (healthy controls [HC] ∩ SCZ] nodes was identified. MVAR models quantified directional interactions between pairs of nodes, and coefficients were evaluated for intergroup differences (HC ≠ SCZ). In exploratory analyses, we quantified statistical effects of neuroleptic dosage on performance and MVAR measures. During Early Encoding, SCZ showed reduced dFC within a frontal-hippocampal-fusiform network, though during Late Encoding reduced dFC was associated with pathways toward the dorsolateral prefrontal cortex (dlPFC). During Early Retrieval, SCZ showed increased dFC in pathways to and from the dorsal anterior cingulate cortex, though during Late Retrieval, patients showed increased dFC in pathways toward the dlPFC, but decreased dFC in pathways from the dlPFC. These discoveries constitute novel extensions of our understanding of task-evoked dysconnection in schizophrenia and motivate understanding of the directional aspect of the dysconnection in schizophrenia. Disordered directionality should be investigated using computational psychiatric approaches that complement the MVAR method used in our work.

Development of Learning Objectives to Guide Enhancement of Chronic Disease Prevention and Management Curricula in Undergraduate Medical Education.

Phenomenon: Chronic disease is a leading cause of death and disability in the United States. With an increase in the demand for healthcare and rising costs related to chronic care, physicians need to be better trained to address chronic disease at various stages of illness in a collaborative and cost-effective manner. Specific and measurable learning objectives are key to the design and evaluation of effective training, but there has been no consensus on chronic disease learning objectives appropriate to medical student education. Approach: Wagner's Chronic Care Model (CCM) was selected as a theoretical framework to guide development of an enhanced chronic disease prevention and management (CDPM) curriculum. Findings of a literature review of CDPM competencies, objectives, and topical statements were mapped to each of the six domains of the CCM to understand the breadth of existing learning topics within each domain. At an in-person meeting, medical educators prepared a survey for the modified Delphi approach. Attendees identified 51 possible learning objectives from the literature review mapping, rephrased the CCM domains as competencies, constructed possible CDPM learning objectives for each competency with the goal of reaching multi-institutional consensus on a limited number of CDPM learning objectives that would be feasible for institutions to use to guide enhancement of medical student curricula related to CDPM. After the meeting, the group developed a survey which included 39 learning objectives. In the study phase of the modified Delphi approach, 32 physician CDPM experts and educators completed an online survey to prioritize the top 20 objectives. The next step occurred at a CDPM interest group in-person meeting with the goal of identifying the top 10 objectives. Findings: The CCM domains were reframed as the following competencies for medical student education: patient self-care management, decision support, clinical information systems, community resources, delivery systems and teams, and health system practice and improvement. Eleven CDPM learning objectives were identified within the six competencies that were most important in developing curriculum for medical students. Insights: These learning objectives cut across education on the prevention and management of individual chronic diseases and frame chronic disease care as requiring the health system science competencies identified in the CCM. They are intended to be used in combination with traditional disease-specific pathophysiology and treatment objectives. Additional efforts are needed to identify specific curricular strategies and assessment tools for each learning objective.

Circadian rhythms, metabolic oscillators, and the target of rapamycin (TOR) pathway: the Neurospora connection.

Circadian (24-h) rhythmicity is a fundamental property of eukaryotic cells, and it is not surprising that it intersects with fundamental metabolic processes. Many links between these two processes have been documented, and speculation has been growing that there may be circadian "metabolic oscillators" that interact with and exist independently of the well-known circadian transcription/translation feedback loops (TTFLs) that have been extensively studied. This review takes a critical look at the evidence for the existence of metabolic oscillators at the cellular level, attempting to answer these questions: does metabolism affect circadian rhythmicity, and vice versa? Is metabolism rhythmic, and if so, is that rhythmicity cell autonomous? Systems displaying "non-canonical rhythmicity" in the absence of functional TTFLs provide opportunities for identifying metabolic oscillators, and this review emphasizes the fungus Neurospora crassa as a model system. Recent papers describing links between the target of rapamycin (TOR) signaling pathway and circadian rhythmicity are highlighted, suggesting the potential for TOR signaling in generating rhythmicity independent of TTFLs.

IL-4/CXCL12 loop is a key regulator of lymphoid stroma function in follicular lymphoma.

Follicular lymphoma (FL) is the most frequent indolent lymphoma and is characterized by the accumulation of germinal center-derived malignant B cells engaged in a bidirectional crosstalk with their supportive microenvironment in invaded lymph nodes (LNs) and bone marrow (BM). T follicular helper (TFH) cells and infiltrating stromal cells have been shown to favor FL B-cell growth, but the mechanisms of their protumoral effect and how the LN/BM microenvironment is converted into a lymphoma-permissive cell niche remain poorly understood. We demonstrated here that FL-infiltrating LN and BM stromal cells overexpressed CXCL12 in situ. Interleukin-4 high (IL-4hi) FL-TFH cells, unlike FL B cells themselves, triggered CXCL12 upregulation in human stromal cell precursors. In agreement, expression of CXCL12 was associated with IL-4 expression and signaling within the FL BM and LN niches. This IL-4/CXCL12 axis was amplified in activated lymphoid stromal cells as shown in our in vitro model of human lymphoid stroma differentiation and in an inducible mouse model of ectopic lymphoid organ formation. Finally, CXCL12 triggered primary FL B-cell activation, migration, and adhesion, a process antagonized by BTK and PI3K inhibitors. These data identified the IL-4/CXCL12 loop as a previously unrecognized pathway involved in lymphoid stroma polarization and as a potential therapeutic target in FL patients.

Advancing the clinical nurse leader model through academic-practice-policy partnership.

The nursing profession is tasked with identifying and evaluating models of care with potential to add value to health care delivery. In consideration of this goal, we describe the Clinical Nurse Leader (CNL) initiative and the activities of a national-level CNL research collaborative. The CNL initiative, launched by the American Association of Colleges of Nursing in collaboration with education and healthcare leaders, has delineated CNL education curriculum and practice competencies, and fostered the creation of academic-practice-policy partnerships to pilot CNL integration into frontline nursing care delivery. The partnership has evolved into an Agency for Healthcare Research and Quality affiliate practice-based research network, the CNL Research Collaborative, which links research, policy, education, and practice stakeholders to advance the CNL evidence base. We summarize foundational CNLRC research to explain CNL practice, quantify CNL effectiveness, and bring clarity to how CNLs can be implemented to consistently influence care, quality, and safety.

Developing the Clinical Nurse Leader Survey Instrument: A Modified Delphi Study.

Clinical nurse leader (CNL)-integrated care delivery is an emerging nursing model, with growing adoption in diverse health systems. To generate a robust evidence base for this promising nursing model, it is necessary to measure CNL practice to explicitly link it to observed quality and safety outcome improvements. This study used a modified Delphi approach with an expert CNL panel to develop and test the face, content, and construct validity of the CNL Practice Survey instrument.

CD10 delineates a subset of human IL-4 producing follicular helper T cells involved in the survival of follicular lymphoma B cells.

In follicular lymphoma (FL), follicular helper T cells (TFH) have been depicted as one of the main components of the malignant B-cell niche and a promising therapeutic target. Although defined by their capacity to sustain FL B-cell growth together with specific gene expression and cytokine secretion profiles, FL-TFH constitute a heterogeneous cell population. However, specific markers reflecting such functional heterogeneity are still lacking. In this study, we demonstrate that CD10 identifies a subset of fully functional germinal center TFH in normal secondary lymphoid organs. Importantly, this subset is amplified in the FL context, unlike in other B-cell lymphomas with a follicular growth pattern. Furthermore, whereas FL-TFH produce high levels of interleukin (IL)-21 and low levels of IL-17 irrespectively of their CD10 expression, CD10(pos) FL-TFH specifically exhibit an IL-4(hi)IFN-γ(lo)TNF-α(hi) cytokine profile associated with a high capacity to sustain directly and indirectly malignant B-cell survival. Altogether, our results highlight the important role of this novel functional subset in the FL cell niche.

Educational Changes to Support Advanced Practice Nursing Education.

Educational factors limit the number of advanced practice registered nurse (APRN) graduates to meet the growing workforce demands. Healthcare dynamics are necessitating a shift in how nursing education envisions, creates, and implements clinical learning opportunities. The current clinical education model in APRN programs continues to be the same as it was 45 years ago when the student numbers were much smaller. New approaches in graduate nursing education are needed to address the shortage of APRNs in primary and acute care areas. Determining competency based on the number of clinical hours can be inefficient, ineffective, and costly and limits the ability to increase capacity. Little research exists in graduate nursing education to support the effectiveness and efficiency of current hours of clinical required for nurse practitioner students. Simulation and academic-practice partnership models can offer innovative approaches to nurse practitioner education for clinical training, with the goal of producing graduates who can provide safe, quality care within the complex practice-based environment of the nation's evolving healthcare system.

The yin and the yang of follicular lymphoma cell niches: role of microenvironment heterogeneity and plasticity.

Follicular lymphoma (FL) results from the malignant transformation of germinal center B cells and is characterized by recurrent genetic alterations providing a direct growth advantage or facilitating interaction with tumor microenvironment. In agreement, accumulating evidences suggest a dynamic bidirectional crosstalk between FL B cells and surrounding non-malignant cells within specialized tumor niches in both invaded lymph nodes and bone marrow. Infiltrating stromal cells, macrophages, and T/NK cell subsets either contribute to anti-tumor immune response, or conversely form a tumor supportive network promoting FL B cell survival, growth, and drug resistance. This review depicts the phenotypic heterogeneity and functional plasticity of the most important FL cell partners and describes their complex interplay. We also unravel how malignant B cells recruit and subvert accessory immune and stromal cells to trigger their polarization toward a supportive phenotype. Based on these observations, innovative therapeutic approaches have been recently proposed, in order to benefit from local anti-tumor immunity and/or to selectively target the protective cell niche.

Expression profiling of in vivo ductal carcinoma in situ progression models identified B cell lymphoma-9 as a molecular driver of breast cancer invasion.

INTRODUCTION: There are an estimated 60,000 new cases of ductal carcinoma in situ (DCIS) each year. A lack of understanding in DCIS pathobiology has led to overtreatment of more than half of patients. We profiled the temporal molecular changes during DCIS transition to invasive ductal carcinoma (IDC) using in vivo DCIS progression models. These studies identified B cell lymphoma-9 (BCL9) as a potential molecular driver of early invasion. BCL9 is a newly found co-activator of Wnt-stimulated ß-catenin-mediated transcription. BCL9 has been shown to promote progression of multiple myeloma and colon carcinoma. However BCL9 role in breast cancer had not been previously recognized. METHODS: Microarray and RNA sequencing were utilized to characterize the sequential changes in mRNA expression during DCIS invasive transition. BCL9-shRNA knockdown was performed to assess the role of BCL9 in in vivo invasion, epithelial-mesenchymal transition (EMT) and canonical Wnt-signaling. Immunofluorescence of 28 patient samples was used to assess a correlation between the expression of BCL9 and biomarkers of high risk DCIS. The cancer genome atlas data were analyzed to assess the status of BCL9 gene alterations in breast cancers. RESULTS: Analysis of BCL9, by RNA and protein showed BCL9 up-regulation to be associated with DCIS transition to IDC. Analysis of patient DCIS revealed a significant correlation between high nuclear BCL9 and pathologic characteristics associated with DCIS recurrence: Estrogen receptor (ER) and progesterone receptor (PR) negative, high nuclear grade, and high human epidermal growth factor receptor2 (HER2). In vivo silencing of BCL9 resulted in the inhibition of DCIS invasion and reversal of EMT. Analysis of the TCGA data showed BCL9 to be altered in 26 % of breast cancers. This is a significant alteration when compared to HER2 (ERBB2) gene (19 %) and estrogen receptor (ESR1) gene (8 %). A significantly higher proportion of basal like invasive breast cancers compared to luminal breast cancers showed BCL9 amplification. CONCLUSION: BCL9 is a molecular driver of DCIS invasive progression and may predispose to the development of basal like invasive breast cancers. As such, BCL9 has the potential to serve as a biomarker of high risk DCIS and as a therapeutic target for prevention of IDC.

Mesenchymal stromal cells orchestrate follicular lymphoma cell niche through the CCL2-dependent recruitment and polarization of monocytes.

Accumulating evidence indicates that infiltrating stromal cells contribute directly and indirectly to tumor growth in a wide range of cancers. In follicular lymphoma (FL), malignant B cells are found admixed with heterogeneous lymphoid-like stromal cells within invaded lymph nodes and BM. In addition, mesenchymal stromal cells (MSCs) support in vitro FL B-cell survival, in particular after their engagement toward lymphoid differentiation. We show here that BM-MSCs obtained from patients with FL (FL-MSCs) display a specific gene expression profile compared with MSCs obtained from healthy age-matched donors (HD-MSCs). This FL-MSC signature is significantly enriched for genes associated with a lymphoid-like commitment. Interestingly, CCL2 could be detected at a high level within the FL-cell niche, is up-regulated in HD-MSCs by coculture with malignant B cells, and is overexpressed by FL-MSCs, in agreement with their capacity to recruit monocytes more efficiently than HD-MSCs. Moreover, FL-MSCs and macrophages cooperate to sustain malignant B-cell growth, whereas FL-MSCs drive monocyte differentiation toward a proangiogenic and lipopolysaccharide-unresponsive phenotype close to that of tumor-associated macrophages. Altogether, these results highlight the complex role of FL stromal cells that promote direct tumor B-cell growth and orchestrate FL-cell niche, thus emerging as a potential therapeutic target in this disease.

Health and health care of mothers and children in a suburban area of Luanda, Angola.

Population health data available in Angola are often insufficient to guide the planning of health interventions. To address this gap, the goal of the present study was to investigate the health of mothers and infants in a suburban municipality in Luanda (Cacuaco), in order to provide a baseline for future comparisons. This was a prevalence study investigating infants younger than 2 years of age and their mothers. Mothers were interviewed, and children's height and weight were measured. Of 749 mothers interviewed, 98.5% (95% CI 98.2-99.1%) had at least one prenatal visit and 51.7% (95% CI 47.4-56.3%) had a health card. Most mothers with a health card had their first prenatal visit before the 20th week of pregnancy, and had at least four prenatal visits; 81.1% (95% CI 78.3-84.1%) of mothers also had their child's health card. Prevalence of exclusive breastfeeding at 6 months was 19% (95% CI 16.2-23.1%). Prevalence of low height-for-age and low BMI-for-age were 32 and 6%, respectively. Mothers with higher education levels were more likely to have had their first prenatal visit earlier, to have had more prenatal visits, to have given birth at a health facility, and to have her own and her child's health cards. Results showed a high prevalence of prenatal care and a low frequency of acute malnutrition. Maternal education level, among factors studied, was the predominant correlate of more positive health behaviors. These findings suggest important progress of mother and child health in Cacuaco, and may serve as a baseline for the planning of health interventions.

A new mutation affecting FRQ-less rhythms in the circadian system of Neurospora crassa.

We are using the fungus Neurospora crassa as a model organism to study the circadian system of eukaryotes. Although the FRQ/WCC feedback loop is said to be central to the circadian system in Neurospora, rhythms can still be seen under many conditions in FRQ-less (frq knockout) strains. To try to identify components of the FRQ-less oscillator (FLO), we carried out a mutagenesis screen in a FRQ-less strain and selected colonies with altered conidiation (spore-formation) rhythms. A mutation we named UV90 affects rhythmicity in both FRQ-less and FRQ-sufficient strains. The UV90 mutation affects FRQ-less rhythms in two conditions: the free-running long-period rhythm in choline-depleted chol-1 strains becomes arrhythmic, and the heat-entrained rhythm in the frq(10) knockout is severely altered. In a FRQ-sufficient background, the UV90 mutation causes damping of the free-running conidiation rhythm, reduction of the amplitude of the FRQ protein rhythm, and increased phase-resetting responses to both light and heat pulses, consistent with a decreased amplitude of the circadian oscillator. The UV90 mutation also has small but significant effects on the period of the conidiation rhythm and on growth rate. The wild-type UV90 gene product appears to be required for a functional FLO and for sustained, high-amplitude rhythms in FRQ-sufficient conditions. The UV90 gene product may therefore be a good candidate for a component of the FRQ-less oscillator. These results support a model of the Neurospora circadian system in which the FRQ/WCC feedback loop mutually interacts with a single FLO in an integrated circadian system.