RESUMO
BACKGROUND AND AIMS: Plants depend fundamentally on establishment from seed. However, protocols in trait-based ecology currently estimate seed size but not seed number. This can be rectified. For annuals, seed number should simply be a positive function of vegetative biomass and a negative function of seed size. METHODS: Using published values of comparative seed number as the 'gold standard' and a large functional database, comparative seed yield and number per plant and per m2 were predicted by multiple regression. Subsequently, ecological variation in each was explored for English and Spanish habitats, newly calculated C-S-R strategies and changed abundance in the British flora. KEY RESULTS: As predicted, comparative seed mass yield per plant was consistently a positive function of plant size and competitive ability, and largely independent of seed size. Regressions estimating comparative seed number included, additionally, seed size as a negative function. Relationships differed numerically between regions, habitats and C-S-R strategies. Moreover, some species differed in life history over their geographical range. Comparative seed yield per m2 was positively correlated with FAO crop yield, and increasing British annuals produced numerous seeds. Nevertheless, predicted values must be viewed as comparative rather than absolute: they varied according to the 'gold standard' predictor used. Moreover, regressions estimating comparative seed yield per m2 achieved low precision. CONCLUSIONS: For the first time, estimates of comparative seed yield and number for >800 annuals and their predictor equations have been produced and the ecological importance of these regenerative traits has been illustrated. 'Regenerative trait-based ecology' remains in its infancy, with work needed on determinate vs. indeterminate flowering ('bet-hedging'), C-S-R methodologies, phylogeny, comparative seed yield per m2 and changing life history. Nevertheless, this has been a positive start and readers are invited to use estimates for >800 annuals, in the Supplementary data, to help advance 'regenerative trait-based ecology' to the next level.
Assuntos
Plantas , Sementes , Ecossistema , Fenótipo , FilogeniaRESUMO
Background and Aims: While the 'worldwide leaf economics spectrum' (Wright IJ, Reich PB, Westoby M, et al. 2004. The worldwide leaf economics spectrum. Nature : 821-827) defines mineral nutrient relationships in plants, no unifying functional consensus links size attributes. Here, the focus is upon leaf size, a much-studied plant trait that scales positively with habitat quality and components of plant size. The objective is to show that this wide range of relationships is explicable in terms of a seed-phytomer-leaf (SPL) theoretical model defining leaf size in terms of trade-offs involving the size, growth rate and number of the building blocks (phytomers) of which the young shoot is constructed. Methods: Functional data for 2400+ species and English and Spanish vegetation surveys were used to explore interrelationships between leaf area, leaf width, canopy height, seed mass and leaf dry matter content (LDMC). Key Results: Leaf area was a consistent function of canopy height, LDMC and seed mass. Additionally, size traits are partially uncoupled. First, broad laminas help confer competitive exclusion while morphologically large leaves can, through dissection, be functionally small. Secondly, leaf size scales positively with plant size but many of the largest-leaved species are of medium height with basally supported leaves. Thirdly, photosynthetic stems may represent a functionally viable alternative to 'small seeds + large leaves' in disturbed, fertile habitats and 'large seeds + small leaves' in infertile ones. Conclusions: Although key elements defining the juvenile growth phase remain unmeasured, our results broadly support SPL theory in that phytometer and leaf size are a product of the size of the initial shoot meristem (â seed mass) and the duration and quality of juvenile growth. These allometrically constrained traits combine to confer ecological specialization on individual species. Equally, they appear conservatively expressed within major taxa. Thus, 'evolutionary canalization' sensu Stebbins (Stebbins GL. 1974. Flowering plants: evolution above the species level . Cambridge, MA: Belknap Press) is perhaps associated with both seed and leaf development, and major taxa appear routinely specialized with respect to ecologically important size-related traits.
Assuntos
Características de História de Vida , Folhas de Planta/fisiologia , Fenômenos Fisiológicos Vegetais , Sementes/fisiologia , Ecossistema , Inglaterra , Folhas de Planta/anatomia & histologia , Folhas de Planta/crescimento & desenvolvimento , Sementes/anatomia & histologia , Sementes/crescimento & desenvolvimento , SuéciaRESUMO
Large sample volumes are traditionally required for the analysis of waterborne pathogens. The need for large volumes greatly limits the number of samples that can be processed. The aims of this study were to compare extraction and detection procedures for quantifying protozoan parasites and viruses from small volumes of marine water. The intent was to evaluate a logistically simpler method of sample collection and processing that would facilitate direct pathogen measures as part of routine monitoring programs. Samples were collected simultaneously using a bilayer device with protozoa capture by size (top filter) and viruses capture by charge (bottom filter). Protozoan detection technologies utilized for recovery of Cryptosporidium spp. and Giardia spp. were qPCR and the more traditional immunomagnetic separation-IFA-microscopy, while virus (poliovirus) detection was based upon qPCR versus plaque assay. Filters were eluted using reagents consistent with the downstream detection technologies. Results showed higher mean recoveries using traditional detection methods over qPCR for Cryptosporidium (91% vs. 45%) and poliovirus (67% vs. 55%) whereas for Giardia the qPCR-based methods were characterized by higher mean recoveries (41% vs. 28%). Overall mean recoveries are considered high for all detection technologies. Results suggest that simultaneous filtration may be suitable for isolating different classes of pathogens from small marine water volumes. More research is needed to evaluate the suitability of this method for detecting pathogens at low ambient concentration levels.
Assuntos
Cryptosporidium/isolamento & purificação , Giardia/isolamento & purificação , Poliovirus/isolamento & purificação , Água do Mar/microbiologia , Microbiologia da Água , Qualidade da Água , Filtração/métodos , Separação Imunomagnética , Reação em Cadeia da Polimerase , Água do Mar/parasitologiaRESUMO
Little is known about the Australian snubfin (Orcaella heinsohni) and Indo-Pacific humpback (Sousa chinensis) dolphins ('snubfin' and 'humpback dolphins', hereafter) of north-western Australia. While both species are listed as 'near threatened' by the IUCN, data deficiencies are impeding rigorous assessment of their conservation status across Australia. Understanding the genetic structure of populations, including levels of gene flow among populations, is important for the assessment of conservation status and the effective management of a species. Using nuclear and mitochondrial DNA markers, we assessed population genetic diversity and differentiation between snubfin dolphins from Cygnet (nâ=â32) and Roebuck Bays (nâ=â25), and humpback dolphins from the Dampier Archipelago (nâ=â19) and the North West Cape (nâ=â18). All sampling locations were separated by geographic distances >200 km. For each species, we found significant genetic differentiation between sampling locations based on 12 (for snubfin dolphins) and 13 (for humpback dolphins) microsatellite loci (FSTâ=â0.05-0.09; P<0.001) and a 422 bp sequence of the mitochondrial control region (FSTâ=â0.50-0.70; P<0.001). The estimated proportion of migrants in a population ranged from 0.01 (95% CI 0.00-0.06) to 0.13 (0.03-0.24). These are the first estimates of genetic diversity and differentiation for snubfin and humpback dolphins in Western Australia, providing valuable information towards the assessment of their conservation status in this rapidly developing region. Our results suggest that north-western Australian snubfin and humpback dolphins may exist as metapopulations of small, largely isolated population fragments, and should be managed accordingly. Management plans should seek to maintain effective population size and gene flow. Additionally, while interactions of a socio-sexual nature between these two species have been observed previously, here we provide strong evidence for the first documented case of hybridisation between a female snubfin dolphin and a male humpback dolphin.
Assuntos
Golfinhos/genética , Animais , DNA Mitocondrial/genética , Golfinhos/fisiologia , Feminino , Fluxo Gênico , Variação Genética , Genética Populacional , Hibridização Genética , Masculino , Repetições de Microssatélites , Densidade Demográfica , Dinâmica Populacional , Austrália OcidentalRESUMO
False killer whales (Pseudorca crassidens) are large delphinids typically found in deep water far offshore. However, in the Hawaiian Archipelago, there are 2 resident island-associated populations of false killer whales, one in the waters around the main Hawaiian Islands (MHI) and one in the waters around the Northwestern Hawaiian Islands (NWHI). We use mitochondrial DNA (mtDNA) control region sequences and genotypes from 16 nuclear DNA (nucDNA) microsatellite loci from 206 individuals to examine levels of differentiation among the 2 island-associated populations and offshore animals from the central and eastern North Pacific. Both mtDNA and nucDNA exhibit highly significant differentiation between populations, confirming limited gene flow in both sexes. The mtDNA haplotypes exhibit a strong pattern of phylogeographic concordance, with island-associated populations sharing 3 closely related haplotypes not found elsewhere in the Pacific. However, nucDNA data suggest that NWHI animals are at least as differentiated from MHI animals as they are from offshore animals. The patterns of differentiation revealed by the 2 marker types suggest that the island-associated false killer whale populations likely share a common colonization history, but have limited contemporary gene flow.
Assuntos
DNA Mitocondrial/genética , Golfinhos/genética , Genética Populacional , Alelos , Animais , Fluxo Gênico , Loci Gênicos , Variação Genética , Haplótipos , Havaí , Repetições de Microssatélites/genética , Família Multigênica , Filogeografia , Análise de Sequência de DNARESUMO
We construct a state-and-transition model for mammals in tropical savannas in northern Australia to synthesize ecological knowledge and understand mammalian declines. We aimed to validate the existence of alternative mammal assemblage states similar to those in arid Australian grasslands, and to speculate on transition triggers. Based on the arid grassland model, we hypothesized that assemblages are partitioned across rainfall gradients and between substrates. We also predicted that assemblages typical of arid regions in boom periods would be prevalent in savannas with higher and more regular rainfall. Data from eight mammal surveys from the Kimberley region, Western Australia (1994 to 2011) were collated. Survey sites were partitioned across rainfall zones and habitats. Data allowed us to identify three assemblage states: State 0:--low numbers of mammals, State II:--dominated by omnivorous rodents and State III:--dominated by rodents and larger marsupials. Unlike arid grasslands, assemblage dominance by insectivorous dasyurids (State I) did not occur in savannas. Mammal assemblages were partitioned across rainfall zones and between substrates as predicted, but-unlike arid regions-were not related strongly to yearly rainfall. Mammal assemblage composition showed high regional stability, probably related to high annual rainfall and predictable wet season resource pulses. As a consequence, we speculate that perpetually booming assemblages in savannas allow top-down control of the ecosystem, with suppression of introduced cats by the dingo, the region's top predator. Under conditions of low or erratic productivity, imposed increasingly by intense fire regimes and introduced herbivore grazing, dingoes may not limit impacts of cats on native mammals. These interacting factors may explain contemporary declines of savanna mammals as well as historical declines in arid Australia. The cat-ecosystem productivity hypothesis raised here differs from the already-articulated cat-habitat structure hypothesis for mammal declines, and we suggest approaches for explicit testing of transition triggers for competing hypotheses.
Assuntos
Pradaria , Mamíferos/fisiologia , Modelos Teóricos , Clima Tropical , Animais , Austrália , Clima Desértico , Geografia , Chuva , Análise de Regressão , Especificidade da Espécie , Inquéritos e QuestionáriosRESUMO
Studies evaluating the relationship between microbes and human health at non-point source beaches are necessary for establishing criteria which would protect public health while minimizing economic burdens. The objective of this study was to evaluate water quality and daily cumulative health effects (gastrointestinal, skin, and respiratory illnesses) for bathers at a non-point source subtropical marine recreational beach in order to better understand the inter-relationships between these factors and hence improve monitoring and pollution prevention techniques. Daily composite samples were collected, during the Oceans and Human Health Beach Exposure Assessment and Characterization Health Epidemiologic Study conducted in Miami (Florida, USA) at a non-point source beach, and analyzed for several pathogens, microbial source tracking markers, indicator microbes, and environmental parameters. Analysis demonstrated that rainfall and tide were more influential, when compared to other environmental factors and source tracking markers, in determining the presence of both indicator microbes and pathogens. Antecedent rainfall and F+ coliphage detection in water should be further assessed to confirm their possible association with skin and gastrointestinal (GI) illness outcomes, respectively. The results of this research illustrate the potential complexity of beach systems characterized by non-point sources, and how more novel and comprehensive approaches are needed to assess beach water quality for the purpose of protecting bather health.
Assuntos
Praias , Gastroenteropatias/microbiologia , Infecções Respiratórias/microbiologia , Água do Mar/microbiologia , Microbiologia da Água , Colífagos/isolamento & purificação , Enterococcus/isolamento & purificação , Enterovirus/isolamento & purificação , Exposição Ambiental/efeitos adversos , Monitoramento Ambiental/métodos , Monitoramento Epidemiológico , Florida/epidemiologia , Gastroenteropatias/epidemiologia , Humanos , Chuva , Infecções Respiratórias/epidemiologia , Infecções Respiratórias/transmissãoRESUMO
Milk lipids originate by secretion of triglyceride-rich cytoplasmic lipid droplets (CLDs) from mammary epithelial cells. Adipophilin (ADPH)/Plin2, a member of the perilipin family of CLD binding proteins, is hypothesized to regulate CLD production in these cells during differentiation of the mammary gland into a secretory organ. We tested this hypothesis by comparing CLD accumulation in differentiating mammary glands of wild-type and ADPH-deficient mice. ADPH deficiency did not prevent CLD formation; however, it disrupted the increase in CLD size that normally occurs in differentiating mammary epithelial cells. Failure to form large CLDs in ADPH-deficient mice correlated with localization of adipose triglyceride lipase (ATGL) to the CLD surface, suggesting that ADPH promotes CLD growth by inhibiting lipolytic activity. Significantly, mammary alveoli also failed to mature in ADPH-deficient mice, and pups born to these mice failed to survive. The possibility that CLD accumulation and alveolar maturation defects in ADPH-deficient mice are functionally related was tested by in vivo rescue experiments. Transduction of mammary glands of pregnant ADPH-deficient mice with adenovirus encoding ADPH as an N-terminal GFP fusion protein prevented ATGL from localizing to CLDs and rescued CLD size and alveolar maturation defects. Collectively, these data provide direct in vivo evidence that ADPH inhibition of ATGL-dependent lipolysis is required for normal CLD accumulation and alveolar maturation during mammary gland differentiation. We speculate that impairing CLD accumulation interferes with alveolar maturation and lactation by disrupting triglyceride homeostasis in mammary epithelial cells.
Assuntos
Citoplasma/metabolismo , Metabolismo dos Lipídeos , Glândulas Mamárias Animais/fisiologia , Proteínas de Membrana/metabolismo , Animais , Caseínas/metabolismo , Feminino , Proteínas de Fluorescência Verde/metabolismo , Lactação/metabolismo , Lipase/metabolismo , Glândulas Mamárias Animais/metabolismo , Proteínas de Membrana/deficiência , Camundongos , Camundongos Endogâmicos C57BL , Perilipina-2 , Ligação Proteica , Proteínas Recombinantes de Fusão/metabolismoRESUMO
Swimming in ocean water, including ocean water at beaches not impacted by known point sources of pollution, is an increasing health concern. This study was an initial evaluation of the presence of indicator microbes and pathogens and the association among the indicator microbes, pathogens, and environmental conditions at a subtropical, recreational marine beach in south Florida impacted by non-point sources of pollution. Twelve water and eight sand samples were collected during four sampling events at high or low tide under elevated or reduced solar insolation conditions. The analyses performed included analyses of fecal indicator bacteria (FIB) (fecal coliforms, Escherichia coli, enterococci, and Clostridium perfringens), human-associated microbial source tracking (MST) markers (human polyomaviruses [HPyVs] and Enterococcus faecium esp gene), and pathogens (Vibrio vulnificus, Staphylococcus aureus, enterovirus, norovirus, hepatitis A virus, Cryptosporidium spp., and Giardia spp.). The enterococcus concentrations in water and sand determined by quantitative PCR were greater than the concentrations determined by membrane filtration measurement. The FIB concentrations in water were below the recreational water quality standards for three of the four sampling events, when pathogens and MST markers were also generally undetectable. The FIB levels exceeded regulatory guidelines during one event, and this was accompanied by detection of HPyVs and pathogens, including detection of the autochthonous bacterium V. vulnificus in sand and water, detection of the allochthonous protozoans Giardia spp. in water, and detection of Cryptosporidium spp. in sand samples. The elevated microbial levels were detected at high tide and under low-solar-insolation conditions. Additional sampling should be conducted to further explore the relationships between tidal and solar insolation conditions and between indicator microbes and pathogens in subtropical recreational marine waters impacted by non-point source pollution.
Assuntos
Bactérias/isolamento & purificação , Praias , Parasitos/isolamento & purificação , Água do Mar/microbiologia , Vírus/isolamento & purificação , Microbiologia da Água , Animais , Praias/normas , Clostridium perfringens/isolamento & purificação , Cryptosporidium/isolamento & purificação , Enterococcus/isolamento & purificação , Enterococcus faecium/isolamento & purificação , Monitoramento Ambiental , Poluentes Ambientais/isolamento & purificação , Escherichia coli/isolamento & purificação , Florida , Água Doce/microbiologia , Humanos , Polyomavirus/isolamento & purificação , Recreação , Água do Mar/parasitologia , Água do Mar/virologia , Dióxido de Silício , Vírus/genética , Abastecimento de ÁguaRESUMO
Hendra virus (HeV) is a lethal paramyxovirus which emerged in humans in 1994. Poor understanding of HeV dynamics in Pteropus spp. (flying fox or fruit bat) reservoir hosts has limited our ability to determine factors driving its emergence. We initiated a longitudinal field study of HeV in little red flying foxes (LRFF; Pteropus scapulatus) and examined individual and population risk factors for infection, to determine probable modes of intraspecific transmission. We also investigated whether seasonal changes in host behaviour, physiology and demography affect host-pathogen dynamics. Data showed that pregnant and lactating females had significantly higher risk of infection, which may explain previously observed temporal associations between HeV outbreaks and flying fox birthing periods. Age-specific seroprevalence curves generated from field data imply that HeV is transmitted horizontally via faeces, urine or saliva. Rapidly declining seroprevalence between two field seasons suggests that immunity wanes faster in LRFF than in other flying fox species, and highlights the potentially critical role of this species in interspecific viral persistence. The highest seroprevalence was observed when animals showed evidence of nutritional stress, suggesting that environmental processes that alter flying fox food sources, such as habitat loss and climate change, may increase HeV infection and transmission. These insights into the ecology of HeV in flying fox populations suggest causal links between anthropogenic environmental change and HeV emergence.
Assuntos
Quirópteros/virologia , Vírus Hendra/patogenicidade , Infecções por Henipavirus/veterinária , Reprodução/fisiologia , Inanição , Animais , Anticorpos Antivirais/sangue , Quirópteros/fisiologia , Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/virologia , Feminino , Vírus Hendra/imunologia , Infecções por Henipavirus/epidemiologia , Infecções por Henipavirus/virologia , Interações Hospedeiro-Patógeno , Humanos , Lactação , Gravidez , Prenhez , Fatores de Risco , Zoonoses/epidemiologia , Zoonoses/virologiaRESUMO
Adipophilin (ADPH), a member of the perilipin family of lipid droplet-associated proteins, is hypothesized to mediate milk lipid formation and secretion. Unexpectedly, the fat content of milk from ADPH-null mice was only modestly lower than that of wild-type controls, and neither TIP47 nor perilipin appeared to fully compensate for ADPH loss. This prompted us to investigate the possibility that the mutated ADPH gene was not a genuine null mutation. ADPH transcripts were detected in ADPH-null mammary tissue by quantitative real-time PCR, and C-terminal-specific, but not N-terminal-specific, ADPH antibodies detected a single lower molecular weight product and immunostained cytoplasmic lipid droplets (CLDs) and secreted milk fat globules in ADPH-null mammary tissue. Furthermore, stable cell lines expressing cDNA constructs corresponding to the ADPH-null mutation produced a product comparable in size to the one detected in ADPH-null mammary glands and localized to CLDs. Based on these data, we conclude that ADPH-null mice express an N-terminally truncated form of ADPH that retains the ability to promote the formation and secretion of milk lipids.
Assuntos
Lactação , Lipídeos/biossíntese , Glândulas Mamárias Animais/metabolismo , Leite/metabolismo , Peptídeos/genética , Peptídeos/metabolismo , Animais , Feminino , Metabolismo dos Lipídeos , Proteínas de Membrana , Camundongos , Camundongos Mutantes , Peptídeos/química , Perilipina-2RESUMO
PAT proteins (perilipin, adipophilin, and TIP47) are hypothesized to be critical regulators of lipid accumulation in eukaryotic cells. We investigated the developmental relationships between the expression of these proteins and cytoplasmic lipid droplet (CLD) accumulation in differentiating secretory epithelial cells in mouse mammary glands. Adipophilin (ADPH) specifically localized to CLD in differentiating and lactating mammary glands and was found exclusively in the secreted lipid droplet fraction of mouse milk. ADPH transcripts were selectively detected in secretory epithelial cells, and steady-state levels of both ADPH mRNA and protein increased during secretory differentiation in patterns consistent with functional linkage to CLD accumulation. TIP47 also was detected in secretory epithelial cells; however, it had a diffuse punctate appearance, and its mRNA and protein expression patterns did not correlate with CLD accumulation. Perilipin-positive adipose cells and steady-state levels of perilipin mRNA and protein decreased during mammary gland differentiation, suggesting a progressive loss of adipose lipid storage during this process. Collectively, these data demonstrate that increased ADPH expression is a specialized property of differentiated secretory epithelial cells and provide developmental evidence specifically linking increased ADPH expression to increased CLD accumulation. In addition, evidence is presented that the epithelial and adipose compartments of the mammary gland undergo concerted, developmentally regulated shifts in lipid metabolism that increase the availability of fatty acids necessary for lipid synthesis by milk-secreting cells.
Assuntos
Citoplasma/metabolismo , Metabolismo dos Lipídeos/fisiologia , Glândulas Mamárias Animais/crescimento & desenvolvimento , Proteínas de Membrana/fisiologia , Animais , Proteínas de Transporte/metabolismo , Diferenciação Celular , Células Epiteliais/metabolismo , Lactação , Glândulas Mamárias Animais/metabolismo , Camundongos , Perilipina-1 , Perilipina-2 , Perilipina-3 , Fosfoproteínas/metabolismoRESUMO
CCAAT/enhancer-binding protein beta (C/EBPbeta) plays a key role in initiation of adipogenesis in adipose tissue and gluconeogenesis in liver; however, the role of C/EBPbeta in hepatic lipogenesis remains undefined. Here we show that C/EBPbeta inactivation in Lepr(db/db) mice attenuates obesity, fatty liver, and diabetes. In addition to impaired adipogenesis, livers from C/EBPbeta(-/-) x Lepr(db/db) mice had dramatically decreased triglyceride content and reduced lipogenic enzyme activity. C/EBPbeta deletion in Lepr(db/db) mice down-regulated peroxisome proliferator-activated receptor gamma2 (PPARgamma2) and stearoyl-CoA desaturase-1 and up-regulated PPARalpha independent of SREBP1c. Conversely, C/EBPbeta overexpression in wild-type mice increased PPARgamma2 and stearoyl-CoA desaturase-1 mRNA and hepatic triglyceride content. In FAO cells, overexpression of the liver inhibiting form of C/EBPbeta or C/EBPbeta RNA interference attenuated palmitate-induced triglyceride accumulation and reduced PPARgamma2 and triglyceride levels in the liver in vivo. Leptin and the anti-diabetic drug metformin acutely down-regulated C/EBPbeta expression in hepatocytes, whereas fatty acids up-regulate C/EBPbeta expression. These data provide novel evidence linking C/EBPbeta expression to lipogenesis and energy balance with important implications for the treatment of obesity and fatty liver disease.
Assuntos
Adiposidade , Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Diabetes Mellitus/metabolismo , Fígado Gorduroso/metabolismo , Obesidade/metabolismo , Adiposidade/efeitos dos fármacos , Adiposidade/genética , Animais , Proteína beta Intensificadora de Ligação a CCAAT/deficiência , Linhagem Celular , Diabetes Mellitus/genética , Diabetes Mellitus/terapia , Metabolismo Energético/efeitos dos fármacos , Metabolismo Energético/genética , Fígado Gorduroso/genética , Fígado Gorduroso/terapia , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/genética , Hipoglicemiantes/farmacologia , Metformina/farmacologia , Camundongos , Camundongos Knockout , Obesidade/genética , Obesidade/terapia , PPAR alfa/biossíntese , PPAR gama/biossíntese , Palmitatos/farmacologia , Estearoil-CoA Dessaturase/biossíntese , Proteína de Ligação a Elemento Regulador de Esterol 1/biossíntese , Triglicerídeos/metabolismoRESUMO
Although lactation is the only physiological function of the mammary gland, little is known about the molecular events required for secretory activation and milk production. Genetically altered mice have been used extensively to study mammary gland development during puberty and pregnancy, as well as mammary tumorigenesis. A number of approaches have been used to produce genetic modifications in mammary glands of mice, including transgenic mice utilizing mammary specific promoters, traditional knockout mice, mammary-specific gene deletion, and conditionally-regulated transgenes. The same technologies can be used to study secretory activation and lactation; however only a comparatively small number of studies to date have used these approaches to study these events. In this paper we review the technologies available to make genetically modified mice for the study of secretory activation and lactation as well as specific analytical procedures that can be used to characterize mice with lactation defects.
Assuntos
Regulação da Expressão Gênica , Lactação/genética , Glândulas Mamárias Animais/metabolismo , Animais , Feminino , Glândulas Mamárias Animais/anatomia & histologia , Glândulas Mamárias Animais/crescimento & desenvolvimento , Camundongos , Camundongos Transgênicos , Modelos Animais , Regiões Promotoras Genéticas/genéticaRESUMO
Approximately 55% of malaria infections in the Guyana Amazon region are attributed to Plasmodium falciparum while the other 45% are attributed to non-falciparum, mostly Plasmodium vivax. However, little is known about the P. vivax strain types circulating in the region. Using PCR for Plasmodium detection and two genetic markers specific to P. vivax to detect the polymorphic circumsporozoite protein (CSP) and the conserved 19-kDa region of the merozoite surface protein-1 (MSP-1), we investigated the overall Plasmodium strain distribution and population diversity within P. vivax in isolates collected from the blood of infected individuals in the interior Amazon region of Guyana, South America. Out of a total of 250 samples positive for Plasmodium, P. vivax was detected in 30% (76/250) and P. falciparum was detected in 76% (189/250). Mixed infections containing both P. falciparum and P. vivax constituted 6% (15/250) of the total positive samples. Further analysis of P. vivax strains showed that 92% (56/61) of the P. vivax samples hybridized with a probe specific to type VK210, 39% (24/61) hybridized with a probe specific for type VK247, and 25% (15/61) hybridized with a probe specific for the P. vivax-like CS genotype. DNA sequencing of the 19-kDa C-terminal domain in block 13 of MSP-1 amplified from 61 samples from patients infected with P. vivax demonstrated that this region is highly conserved, and all samples were identical at the nucleotide level to the Belem and Salvador-1 types. No synonymous or nonsynonymous mutations were observed in this region of the gene, indicating that current vaccine-development efforts based on the MSP-1(19) fragment would be applicable in Guyana.
Assuntos
Variação Genética/genética , Malária Vivax/genética , Plasmodium vivax/genética , Animais , Primers do DNA , DNA de Protozoário/análise , DNA de Protozoário/genética , Genes de Protozoários , Genótipo , Guiana/epidemiologia , Humanos , Malária Vivax/epidemiologia , Plasmodium vivax/isolamento & purificaçãoRESUMO
PURPOSE: To describe the use of exercise when treating depression in elders and to discuss the data supporting the relationship between increased physical activity and decreased depression. DATA SOURCES: Extensive review of recent scientific literature, both medical and gerontological in content. CONCLUSIONS: Increasing physical activity markedly reduces depressive symptoms and is a safe adjunct or alternative to medication therapy. IMPLICATIONS FOR PRACTICE: Exercise has numerous physical and psychological benefits to patients. Physical activity should be recommended to all patients of all ages.
Assuntos
Transtorno Depressivo/terapia , Terapia por Exercício , Idoso , Transtorno Depressivo/diagnóstico , Humanos , Qualidade de VidaRESUMO
Cytosolic lipid droplets (CLDs), the immediate precursors of milk lipids in lactating animals, undergo cell-specific changes in their formation and intracellular distribution during mammary gland differentiation. Cell biological studies indicate that CLD formation in mammary epithelial cells is regulated in part by AKT-dependent increases in glucose uptake. Proteomic studies show that CLDs from lactating mammary epithelial cells possess a distinct protein composition enriched in molecules involved in their secretion and intracellular transport. CLD secretion is dependent on lactation and requires the purine catabolic enzyme xanthine oxidoreductase (XOR). Confocal immunofluorescence microscopy of XOR in lactating and nonlactating mammary glands and biochemical analysis of secreted CLDs link the secretion process to the formation of a stable tripartite complex between XOR, adipophilin (ADPH), and butyrophilin (Btn). Together these studies provide a molecular and cellular framework for understanding the process of milk lipid formation.
Assuntos
Lactação/metabolismo , Metabolismo dos Lipídeos , Glândulas Mamárias Animais/enzimologia , Glândulas Mamárias Animais/metabolismo , Leite/metabolismo , Animais , Feminino , Regulação Enzimológica da Expressão Gênica/fisiologia , Humanos , Glândulas Mamárias Humanas/enzimologia , Glândulas Mamárias Humanas/metabolismo , Camundongos , Leite/química , Gravidez , Especificidade da Espécie , Xantina Oxidase/metabolismoRESUMO
Nursing is about to realize the worst shortage in history at the same time the first baby boomers are increasing the need for health care. A large component of the current and projected nursing shortage is the aging of the RN work force. Several factors contribute to the aging of the work force, including overall decline in nursing as a chosen profession, the increasing age of nursing graduates, and the aging of the existing RN work force. Job dissatisfaction has been a key issue contributing to the crisis related to recruitment and retention of nurses. Inadequate staffing, heavy workloads, flat salaries, and increased use of mandatory overtime are primary issues related to job dissatisfaction. Job dissatisfaction issues are key components of retention of nursing personnel. Occupational health nurses are experts in dealing with issues of ergonomic challenges, workplace violence, mandatory overtime, stress related injuries, and high stress associated with nursing.
Assuntos
Recursos Humanos de Enfermagem/provisão & distribuição , Enfermagem do Trabalho , Admissão e Escalonamento de Pessoal/organização & administração , Fatores Etários , Atitude do Pessoal de Saúde , Escolha da Profissão , Previsões , Humanos , Satisfação no Emprego , Avaliação das Necessidades , Recursos Humanos de Enfermagem/educação , Recursos Humanos de Enfermagem/psicologia , Recursos Humanos de Enfermagem/tendências , Enfermagem do Trabalho/tendências , Seleção de Pessoal , Reorganização de Recursos Humanos , Salários e Benefícios , Estados Unidos , Recursos HumanosRESUMO
More than 1,000 cases of malaria are diagnosed each year in the United States. Reported numbers, however, may be artificially low because many clinicians fail to consider the diagnosis on presentation, U.S. hospital laboratory technologists have very limited experience in detecting and identifying malaria parasites, and reporting of malaria to state health departments is sporadic in many states. In this study, a rapid malaria diagnostic test, the OptiMAL test (DiaMed; under license from Flow Inc., Portland, Oreg.) was evaluated in six U.S. hospitals and compared with results of microscopy. The OptiMAL test is a 15-min rapid immunochromatographic test that both identifies and differentiates Plasmodium falciparum from non-P. falciparum malaria parasites on the basis of the detection of parasite lactate dehydrogenase in a drop of patient blood. A total of 216 specimens from patients suspected of having malaria were tested. Results indicated that 43 samples (20%) were positive for malaria parasites by microscopy (32 P. falciparum, 11 non-P. falciparum) while 42 (19%) were positive by OptiMAL (31 P. falciparum, 11 non-P. falciparum). The sensitivity of the OptiMAL test was 98%; its specificity was 100%, with positive and negative predictive values of 100 and 99%, respectively. Participating hospital physicians and laboratory directors independently reported that the OptiMAL rapid malaria test was accurate, easy to use, and well accepted by those working in their diagnostic laboratories. The overall conclusion was that integration of the OptiMAL rapid malaria test into the U.S. health care infrastructure would provide an important and easy-to-use tool for the timely diagnosis of malaria.
Assuntos
Malária Falciparum/diagnóstico , Malária Vivax/diagnóstico , Malária/diagnóstico , Plasmodium falciparum/isolamento & purificação , Plasmodium vivax/isolamento & purificação , Animais , Coleta de Amostras Sanguíneas/métodos , Hospitais , Humanos , Malária Falciparum/sangue , Malária Vivax/sangue , Microscopia/métodos , Seleção de Pacientes , Plasmodium falciparum/genética , Plasmodium vivax/genética , Reação em Cadeia da Polimerase/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Estados UnidosRESUMO
Cryptosporidium muris, predominantly a rodent species of Cryptosporidium, is not normally considered a human pathogen. Recently, isolated human infections have been reported from Indonesia, Thailand, France, and Kenya. We report the first case of C. muris in a human in the Western Hemisphere. This species may be an emerging zoonotic pathogen capable of infecting humans.