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Search Results: 1 - 10 of 140009 matches for " Line K Bay "
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Greater Genetic Diversity in Spatially Restricted Coral?Reef Fishes Suggests Secondary Contact among Differentiated Lineages
Line K. Bay,M. Julian Caley
Diversity , 2011, DOI: 10.3390/d3030483
Abstract: The maintenance of genetic diversity is a central goal of conservation. It is the raw material for evolutionary change and if lost, can accelerate extinction of species. According to theory, total genetic diversity should be less in species with restricted ranges and in populations on the margins of distributional ranges, making such species or populations more vulnerable to environmental perturbations. Using mtDNA and nuclear Inter Simple Sequence Repeat (ISSR) data we investigated how the genetic diversity and structure of three con-generic species pairs of coral reef fishes (Pomacentridae) was related to species’ range size and position of populations within these ranges. Estimates of genetic structure did not differ significantly among species, but mtDNA and nucDNA genetic diversities were up to 10 times greater in spatially restricted species compared to their widespread congeners. In two of the three species pairs, the distribution of genetic variation indicated secondary contact among differentiated lineages in the spatially restricted species. In contrast, the widespread species displayed a typical signature of population expansion suggesting recent genetic bottlenecks, possibly associated with the (re) colonization of the Great Barrier Reef. These results indicate that historical processes, involving hybridization and founder effects, possibly associated with Pleistocene sea level fluctuations, have differentially influenced the widespread and spatially restricted coral reef damselfish species studied here.
Meta-population structure in a coral reef fish demonstrated by genetic data on patterns of migration, extinction and re-colonisation
Line K Bay, M Julian Caley, Ross H Crozier
BMC Evolutionary Biology , 2008, DOI: 10.1186/1471-2148-8-248
Abstract: Acanthochromis polyacanthus displayed strong genetic structure among regions (ΦST = 0.81, P < 0.0001) that supported an equilibrium isolation-by-distance model (r = 0.77, P = 0.001). Significant structuring across the continental shelf was only evident in the northern region (ΦST = 0.31, P < 0.001) and no evidence of isolation-by-distance was found within any region. Pairwise ΦST values indicated overall strong but variable genetic structure (mean ΦST among reefs within regions = 0.28, 0.38, 0.41), and asymmetric migration rates among reefs with low genetic structure. Genetic differentiation among younger reefs was greater than among older reefs supporting a meta-population propagule-pool colonisation model. Variation in genetic diversities, demographic expansion and population growth estimates indicated more frequent genetic bottlenecks/founder effects and subsequent population expansion in the central and southern regions compared to the northern one.Our findings provide genetic evidence for meta-population dynamics in a direct developing coral reef fish and we reject the equilibrium island and isolation-by distance models at local spatial scales. Instead, strong non-equilibrium genetic structure appears to be generated by genetic bottlenecks/founder effects associated with population reductions/extinctions and asymmetric migration/(re)-colonisation of such populations. These meta-population dynamics varied across the geographical range examined with edge populations exhibiting lower genetic diversities and higher rates of population expansion than more central populations. Therefore, coral reef species may experience local population reductions/extinctions that promote overall meta-population genetic differentiation.Coral reefs are important ecosystems in ecological, evolutionary and socio-economic contexts but are under increasing threat from anthropogenic impacts [1,2]. The most effective conservation tool available to coral reef managers so far has been the us
Gene Expression Signatures of Energetic Acclimatisation in the Reef Building Coral Acropora millepora
Line K. Bay, Aurélie Guérécheau, Nikos Andreakis, Karin E. Ulstrup, Mikhail V. Matz
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0061736
Abstract: Background Understanding the mechanisms by which natural populations cope with environmental stress is paramount to predict their persistence in the face of escalating anthropogenic impacts. Reef-building corals are increasingly exposed to local and global stressors that alter nutritional status causing reduced fitness and mortality, however, these responses can vary considerably across species and populations. Methodology/Principal Findings We compare the expression of 22 coral host genes in individuals from an inshore and an offshore reef location using quantitative Reverse Transcription-PCR (qRT-PCR) over the course of 26 days following translocation into a shaded, filtered seawater environment. Declines in lipid content and PSII activity of the algal endosymbionts (Symbiodinium ITS-1 type C2) over the course of the experiment indicated that heterotrophic uptake and photosynthesis were limited, creating nutritional deprivation conditions. Regulation of coral host genes involved in metabolism, CO2 transport and oxidative stress could be detected already after five days, whereas PSII activity took twice as long to respond. Opposing expression trajectories of Tgl, which releases fatty acids from the triacylglycerol storage, and Dgat1, which catalyses the formation of triglycerides, indicate that the decline in lipid content can be attributed, at least in part, by mobilisation of triacylglycerol stores. Corals from the inshore location had initially higher lipid content and showed consistently elevated expression levels of two genes involved in metabolism (aldehyde dehydrogenase) and calcification (carbonic anhydrase). Conclusions/Significance Coral host gene expression adjusts rapidly upon change in nutritional conditions, and therefore can serve as an early signature of imminent coral stress. Consistent gene expression differences between populations indicate that corals acclimatize and/or adapt to local environments. Our results set the stage for analysis of these processes in natural coral populations, to better understand the responses of coral communities to global climate change and to develop more efficient management strategies.
Deep-Sequencing Method for Quantifying Background Abundances of Symbiodinium Types: Exploring the Rare Symbiodinium Biosphere in Reef-Building Corals
Kate M. Quigley, Sarah W. Davies, Carly D. Kenkel, Bette L. Willis, Mikhail V. Matz, Line K. Bay
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0094297
Abstract: The capacity of reef-building corals to associate with environmentally-appropriate types of endosymbionts from the dinoflagellate genus Symbiodinium contributes significantly to their success at local scales. Additionally, some corals are able to acclimatize to environmental perturbations by shuffling the relative proportions of different Symbiodinium types hosted. Understanding the dynamics of these symbioses requires a sensitive and quantitative method of Symbiodinium genotyping. Electrophoresis methods, still widely utilized for this purpose, are predominantly qualitative and cannot guarantee detection of a background type below 10% of the total Symbiodinium population. Here, the relative abundances of four Symbiodinium types (A13, C1, C3, and D1) in mixed samples of known composition were quantified using deep sequencing of the internal transcribed spacer of the ribosomal RNA gene (ITS-2) by means of Next Generation Sequencing (NGS) using Roche 454. In samples dominated by each of the four Symbiodinium types tested, background levels of the other three types were detected when present at 5%, 1%, and 0.1% levels, and their relative abundances were quantified with high (A13, C1, D1) to variable (C3) accuracy. The potential of this deep sequencing method for resolving fine-scale genetic diversity within a symbiont type was further demonstrated in a natural symbiosis using ITS-1, and uncovered reef-specific differences in the composition of Symbiodinium microadriaticum in two species of acroporid corals (Acropora digitifera and A. hyacinthus) from Palau. The ability of deep sequencing of the ITS locus (1 and 2) to detect and quantify low-abundant Symbiodinium types, as well as finer-scale diversity below the type level, will enable more robust quantification of local genetic diversity in Symbiodinium populations. This method will help to elucidate the role that background types have in maximizing coral fitness across diverse environments and in response to environmental change.
Fluorescence into flat and structured radiation continua: An atomic density matrix without a master equation
Soren Bay,P. Lambropoulos,K. Molmer
Physics , 1997, DOI: 10.1103/PhysRevLett.79.2654
Abstract: We investigate an atomic $\Lambda$-system with one transition coupled to a laser field and a flat continuum of vacuum modes and the other transition coupled to field modes near the edge of a photonic band gap. The system requires simultaneous treatment of Markovian and non-Markovian dissipation processes, but the photonic band gap continuum can not be eliminated within a density matrix treatment. Instead we propose a formalism based on Monte-Carlo wavefunctions, and we present results relevant to an experimental characterization of a structured continuum.
Psycho-Physiological Combined Therapy on the Sexual Desire  [PDF]
Roohallah Bay, Shaiful Bahari Ismail, Fatemeh Bay
Open Journal of Urology (OJU) , 2013, DOI: 10.4236/oju.2013.36049
Abstract:

Objective: Hypoactive Sexual Desire is characterized as a lack or absence of sexual fantasies and desire for sexual activity. The current study examines the effects of psycho-physiological therapy (stretch therapy combined with breathing exercise) on the sexual desire among heterosexual men. Methods: We used “convenience sampling” for this research; 80 people were recruited. For collection of data, we used an identical quasi-experimental design called “nonequivalent control group.” Therapy sessions each lasting (20) 90 to 120 min were carried out on 3 alternate days of week. The volunteers have been selected from heterosexual men with stable relationship, those who married minimum of 6 months, within 20 to 55 years old, who attended to HUSM Family Clinic. Pre-tests, post-tests, and follow-up tests were conducted in a HUSM clinic (Malaysia). For assessment we used Hurlbert Index of Sexual Desire (HISD). Results: The psycho-physiological group had better post-test scores compared to the control group. Also follow-up test scores were marginally better compared to the control group, but this difference did not reach statistical significance. Also age and education level of participants didn’t have any significant effect on this intervention.

Infection Dynamics Vary between Symbiodinium Types and Cell Surface Treatments during Establishment of Endosymbiosis with Coral Larvae
Line Kolind Bay,Vivian Ruth Cumbo,David Abrego,Johnathan Travis Kool,Tracy Danielle Ainsworth,Bette Lynn Willis
Diversity , 2011, DOI: 10.3390/d3030356
Abstract: Symbioses between microbes and higher organisms underpin high diversity in many ecosystems, including coral reefs, however mechanisms underlying the early establishment of symbioses remain unclear. Here we examine the roles of Symbiodinium type and cell surface recognition in the establishment of algal endosymbiosis in the reef-building coral, Acropora tenuis. We found 20–70% higher infection success (proportion of larvae infected) and five-fold higher Symbiodinium abundance in larvae exposed to ITS-1 type C1 compared to ITS-1 type D in the first 96 h following exposure. The highest abundance of Symbiodinium within larvae occurred when C1-type cells were treated with enzymes that modified the 40–100 kD glycome, including glycoproteins and long chain starch residues. Our finding of declining densities of Symbiodinium C1 through time in the presence of intact cell surface molecules supports a role for cell surface recognition molecules in controlling post-phagocytosis processes, leading to rejection of some Symbiodinium types in early ontogeny. Reductions in the densities of unmodified C1 symbionts after 96 h, in contrast to increases in D symbionts may suggest the early initiation of a winnowing process contributing to the establishment of Symbiodinium D as the dominant type in one-month old juveniles of A. tenuis.
Leukemia Inhibitory Factor Downregulates Human Papillomavirus-16 Oncogene Expression and Inhibits the Proliferation of Cervical Carcinoma Cells
Joseph M. Bay,Bruce K. Patterson,Nelson N. H. Teng
Infectious Diseases in Obstetrics and Gynecology , 2011, DOI: 10.1155/2011/463081
Abstract: The constitutive proliferation and resistance to differentiation and apoptosis of neoplastic cervical cells depend on sustained expression of human papillomavirus oncogenes. Inhibition of these oncogenes is a goal for the prevention of progression of HPV-induced neoplasias to cervical cancer. SiHa cervical cancer cells were transfected with an HPV-16 promoter reporter construct and treated with leukemia inhibitory factor (LIF), a human cytokine of the interleukin 6 superfamily. SiHa and CaSki cervical cancer cells were also assessed for proliferation by MTT precipitation, programmed cell death by flow cytometry, and HPV E6 and E7 expression by real-time PCR. LIF-treated cervical cancer cells showed significantly reduced HPV LCR activation, reduced levels of E6 and E7 mRNA, and reduced proliferation. We report the novel use of LIF to inhibit viral oncogene expression in cervical cancer cells, with concomitant reduction in proliferation suggesting re-engagement of cell-cycle regulation. 1. Introduction Human Papillomavirus (HPV) is a necessary causative agent for cervical cancer [1, 2], the second most common cancer in women [3] and third overall cause of cancer mortality worldwide [4]. HPV has also been detected in anal cancer [5], cancers of the head and neck, particularly the oropharynx and larynx [5, 6], and there is evidence that some breast cancers contain HPV genomes [7]. At present, no approved, effective nonsurgical intervention for cervical dysplasia or for the underlying HPV infection exists. For localized and advanced localized cervical carcinoma, the concurrent administration of chemotherapy and radiation has been successful, if significantly toxic, but the treatment of recurrent and metastatic disease remains a challenge. For metastatic cervical cancer, standard chemotherapy is generally palliative rather than curative, and there is limited experience with biologics in this group of patients; therefore, a new treatment modality is clearly needed. With over 13,000 cases of invasive cervical cancer, 50,000 cases of carcinoma in situ, and as many as 1,000,00 cases of cervical dysplasia diagnosed each year in the US alone, and with the majority of spending going to followup and treatment of neoplasia, a noninvasive treatment would have a tremendous effect on both women’s health and the financial burden of HPV. The expression of the viral gene products E6 and E7, regulated by the viral long control region (LCR), is also predictive of progression toward cancer: higher levels of viral mRNA correlate with higher-grade lesions [8]. E6 [9] and E7 [9,
Levels of serum B12, folic acid and homocysteine in thromboembolic diseases on admission to the Emergency Department
A Bay?r, K U?ar Karabulut, A Ak
Critical Care , 2011, DOI: 10.1186/cc9434
Abstract: This study included 100 subjects with acute myocardial infarctus (AMI), acute pulmonary embolism, deep vein thrombosis, ischemic cerebrovascular disease (ICD), acute mesentery embolism, and peripheric artery embolism (PAE), and 110 healthy voluntary subjects were included in the control group. Vitamin B12, folic acid and homocysteine levels were examined in the blood samples obtained at admission, The data were loaded onto SPSS 16 for Windows program. P ≤ 0.05 was considered significant.Mean serum homocysteine and plasma vitamin B12 levels were significantly higher in the patient group than the control group (P = 0.002 and 0.000 respectively). There was no significant difference in the levels of folic acid between the patient and control groups. Mean serum B12 values of the AMI and ICD groups in the patient group were significantly lower than those of the control group (P < 0.05). Serum folic acid values of the PAE and AMI groups were considerably lower than the control group (P < 0.05). Plasma homocysteine levels were significantly higher in all patient groups according to their diagnosis than the control group (P < 0.05).Mean serum homocysteine and plasma vitamin B12 levels were significantly higher in the patient group than the control group (P = 0.002 and 0.000 respectively). There was no significant difference in the levels of folic acid between the patient and control groups. Mean serum B12 values of the AMI and ICD groups in the patient group were significantly lower than those of the control group (P < 0.05). Serum folic acid values of the PAE and AMI groups were considerably lower than the control group (P < 0.05). Plasma homocysteine levels were significantly higher in all patient groups according to their diagnosis than the control group (P < 0.05).
Effects of thyroid hormones on major cardiovascular risk in acute coronary syndromes
A Bayrak, A Bay?r, K U?ar Karabulut
Critical Care , 2011, DOI: 10.1186/cc9421
Abstract: The study group included 110 patients without known thyroid dysfunction who were referred to the Emergency Department with acute coronary syndrome. FT3, FT4 and TSH levels were measured in all patients on admission. Patients were divided into STEMI, NSTEMI and UAP groups. Patient records were checked at 3 and 6 months of discharge in terms of sudden cardiac death and major cardiovascular events. The relationship between thyroid hormone levels and acute cardiac death and major cardiovascular disorders at 3 and 6 months of discharge was evaluated.The mean TSH, FT3 and FT4 levels of the study group versus control group were as follows: TSH levels of study group 1.87 ± 1.73 μIU/ml, FT3 3.2 ± 1.34 pg/ml, FT4 1.45 ± 0.64 ng/dl. Abnormalities in the thyroid function tests were noted in 26 patients (23.6%). Of these seven patients (6.36%) had subclinical hypothyroidism, two patients (1.8%) had euthyroid sick syndrome and 10 patients (9%) had high serum FT4 levels despite normal FT3 and TSH values.We noted subclinical hypothyroidism, less frequently euthyroid sick syndrome and hyperthyroidism. No relationship was noted between thyroid hormone levels and sudden cardiac death and major cardiovascular disorders at 3 and 6 months follow-up. However, studies including larger patient groups are needed to clarify if there is a relationship between thyroid hormone levels on admission and sudden death and major cardiovascular events in patients with acute coronary syndrome.
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