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Publication
Journal: Frontiers in Microbiology
April/28/2014
Abstract
Microbial autotroph-heterotroph interactions influence biogeochemical cycles on a global scale, but the diversity and complexity of natural systems and their intractability to in situ manipulation make it challenging to elucidate the principles governing these interactions. The study of assembling phototrophic biofilm communities provides a robust means to identify such interactions and evaluate their contributions to the recruitment and maintenance of phylogenetic and functional diversity over time. To examine primary succession in phototrophic communities, we isolated two unicyanobacterial consortia from the microbial mat in Hot Lake, Washington, characterizing the membership and metabolic function of each consortium. We then analyzed the spatial structures and quantified the community compositions of their assembling biofilms. The consortia retained the same suite of heterotrophic species, identified as abundant members of the mat and assigned to Alphaproteobacteria, Gammaproteobacteria, and Bacteroidetes. Autotroph growth rates dominated early in assembly, yielding to increasing heterotroph growth rates late in succession. The two consortia exhibited similar assembly patterns, with increasing relative abundances of members from Bacteroidetes and Alphaproteobacteria concurrent with decreasing relative abundances of those from Gammaproteobacteria. Despite these similarities at higher taxonomic levels, the relative abundances of individual heterotrophic species were substantially different in the developing consortial biofilms. This suggests that, although similar niches are created by the cyanobacterial metabolisms, the resulting webs of autotroph-heterotroph and heterotroph-heterotroph interactions are specific to each primary producer. The relative simplicity and tractability of the Hot Lake unicyanobacterial consortia make them useful model systems for deciphering interspecies interactions and assembly principles relevant to natural microbial communities.
Publication
Journal: European Journal of Clinical Pharmacology
July/8/1984
Abstract
Furosemide 40 mg was administered to 8 healthy subjects as an i.v. bolus dose, as 1 tablet in the fasting state, and as 1 tablet and a solution after food intake. The i.v. data gave a total body clearance of 162 +/- 10.8 ml/min and a renal clearance of 117 +/- 11.3 ml/min; the volume of distribution at steady state was 8.3 +/- 0.61. Oral administration gave a bio-availability of the tablet (fasting) of 51%. Food intake slightly reduced the bioavailability, but not to a significant extent. There was no significant difference in availability between the tablet and the solution. Moment analysis gave a mean residence time after the i.v. dose, MRTi .v., of 51 +/- 1.5 min. The mean absorption times (MAT) for all oral doses were significantly longer than the MRTi .v., indicating absorption rate-limited kinetics of furosemide. On average, food delayed the absorption by 60 min. The MAT for the tablet in the postprandial state was significantly longer than for the solution, indicating dissolution rate-limited absorption of the tablet.
Publication
Journal: DNA Repair
May/26/2009
Abstract
Chromatin remodeling is emerging as a critical regulator of DNA repair factor access to DNA damage, and optimum accessibility of these factors is a major determinant of DNA repair outcome. Hence, chromatin remodeling is likely to play a key role in genome stabilization and tumor suppression. We previously showed that nucleosome eviction near double-strand breaks (DSBs) in yeast is regulated by the INO80 nucleosome remodeling complex and is defective in mutants lacking the Arp8 subunit of INO80. In the absence of homologous donor sequences, RPA recruitment to a DSB appeared normal in arp8Delta, but Rad51 recruitment was defective. We now show that the early strand invasion step of homologous recombination (HR) is markedly delayed in an arp8Delta haploid, but there is only a minor defect in haploid HR efficiency (MAT switching). In an arp8Delta diploid, interhomolog DSB repair by HR shows a modest defect that is partially suppressed by overexpression of Rad51 or its mediator, Rad52. In wild type cells, DSB repair typically results in gene conversion, and most gene conversion tracts are continuous, reflecting efficient mismatch repair of heteroduplex DNA. In contrast, arp8Delta gene conversion tracts are longer and frequently discontinuous, indicating defects in late stages of HR. Interestingly, when a homologous donor sequence is present, Rad51 is recruited normally to a DSB in arp8Delta, but its transfer to the donor is delayed, and this correlates with defective displacement of donor nucleosomes. We propose that retained nucleosomes at donors destabilize heteroduplex DNA or impair mismatch recognition, reflected in delayed strand invasion and altered conversion tracts.
Publication
Journal: Applied and Environmental Microbiology
August/25/2011
Abstract
A library of engineered promoters of various strengths is a useful genetic tool that enables the fine-tuning and precise control of gene expression across a continuum of broad expression levels. The methylotrophic yeast Pichia pastoris is a well-established expression host with a large academic and industrial user base. To facilitate manipulation of gene expression spanning a wide dynamic range in P. pastoris, we created a functional promoter library through mutagenesis of the constitutive GAP promoter. Using yeast-enhanced green fluorescent protein (yEGFP) as the reporter, 33 mutants were chosen to form the functional promoter library. The 33 mutants spanned an activity range between ∼0.6% and 19.6-fold of the wild-type promoter activity with an almost linear fluorescence intensity distribution. After an extensive characterization of the library, the broader applicability of the results obtained with the yEGFP reporter was confirmed using two additional reporters (β-galactosidase and methionine adenosyltransferase [MAT]) at the transcription and enzyme activity levels. Furthermore, the utility of the promoter library was tested by investigating the influence of heterologous MAT gene expression levels on cell growth and S-adenosylmethionine (SAM) production. The extensive characterization of the promoter strength enabled identification of the optimal MAT activity (around 1.05 U/mg of protein) to obtain maximal volumetric SAM production. The promoter library permits precise control of gene expression and quantitative assessment that correlates gene expression level with physiologic parameters. Thus, it is a useful toolbox for both basic and applied research in P. pastoris.
Publication
Journal: Gait & posture
June/10/2009
Abstract
Gait variability is suggested to be a quantifiable measure to evaluate mobility impairments. However, it is unknown whether gait variability could be used as a marker of impaired walking performance post-stroke. Therefore, the purpose of this study was to determine whether gait variability measures could be used as walking performance measures post-stroke. Hemiparetic variability was compared to healthy gait variability and associated to clinical assessments that evaluate impaired performance post-stroke. Spatiotemporal characteristics were collected from 94 persons with post-stroke hemiparesis and 22 similarly aged healthy persons as they walked over an instrumented mat. Gait variability was calculated as the standard deviation in step lengths, stride widths, pre-swing, swing and stride times. Hemiparetic performance was evaluated using lower-extremity Fugl-Meyer grading, dynamic gait index scale (available in population sub-sets) and an asymmetry index. Results revealed that variability increased in step length, swing, pre-swing and stride times (p<.001) during hemiparetic walking as compared to healthy gait. Paretic leg swing time variability was increased compared to the non-paretic during hemiparetic walking (p<.001). Between-leg differences in variability for other spatiotemporal characteristics were revealed in participants with the most impaired performance. Further, increased step variability and reduced width variability related to poor performance outcomes (severe hemiparesis, asymmetrical gait and poor balance). Patterns of gait variability were evident within sub-groups of the hemiparetic population. Results of this study suggest that between-leg differences in swing and pre-swing time variability, increased step length and stride time variability and decreased width variability are quantifiable markers of impaired walking performance poststroke.
Publication
Journal: Laboratory Investigation
October/28/2008
Abstract
Endotoxemia participates in the pathogenesis of many liver injuries. Lipopolysaccharide (LPS) was shown to inactivate hepatic methionine adenosyltransferase (MAT), the enzyme responsible for S-adenosylmethionine (SAMe) biosynthesis. SAMe treatment was shown to prevent the LPS-induced increase in tumor necrosis factor-alpha, which may be one of its beneficial effects. SAMe is also an important precursor of glutathione (GSH) and GSH was shown to ameliorate LPS-induced hepatotoxicity. The aims of this work were to examine changes in SAMe and GSH homeostasis during endotoxemia and the effect of SAMe. Mice received SAMe or vehicle pretreatment followed by LPS and were killed up to 18 h afterward. Unexpectedly, we found hepatic SAMe level increased 67% following LPS treatment while S-adenosylhomocysteine level fell by 26%, suggesting an increase in SAMe biosynthesis and/or block in transmethylation. The mRNA and protein levels of MATMATMATMAT activity remained inhibited 18 h after LPS. The major methyltransferase that catabolizes hepatic SAMe is glycine N-methyltransferase, whose expression fell by 65% following LPS. Hepatic GSH level fell more than 50% following LPS, coinciding with a comparable fall in the mRNA and protein levels of glutamate-cysteine ligase (GCL) catalytic (GCLC) and modifier subunits (GCLM). SAMe pretreatment prevented the fall in GCLC and attenuated the fall in GCLM expression and GSH level. SAMe pretreatment prevented the LPS-induced increase in plasma alanine transaminases levels but not the LPS-induced increase in hepatic mRNA levels of proinflammatory cytokines. It further enhanced LPS-induced increase in interleukin-10 mRNA level. Taken together, the hepatic response to LPS is to upregulate MAT expression and inhibit SAMe utilization. GSH is markedly depleted largely due to lower expression of GCL. Interestingly, SAMe treatment prevented the fall in GCL and helped to preserve the GSH store and prevent liver injury.
Publication
Journal: NeuroRehabilitation
April/10/2006
Abstract
Our study aims were: 1) to determine whether assisted weight bearing or additional weight bearing is more beneficial to the improvement of function and increased stability in gait and dynamic balance in patients with Parkinsonism, compared with matched controls (treadmill alone). Twenty-three men and women participants (M +/- SD = 74.5 +/- 9.7 yrs; Males = 19, Females = 4) with Parkinsonism were in the study. Participants staged at 1-7 (M +/- SD = 3.96 +/- 1.07) using the Hoehn & Yahr scale. All participants were tested before, after the intervention (within one week), and four weeks later on: 1) dynamic posturography, 2) Berg Balance scale, 3) United Parkinson's Disease Rating Scale (UPDRS), 4) biomechanical assessment of strength and range of motion, and 5) Gaitrite force sensitive gait mat. Group 1 (treadmill control group), received treadmill training with no loading or unloading. Group 2 (unweighted group), walked on the treadmill assisted by the Biodex Unweighing System at a 25% body weight reduction. Group 3 (weighted group), ambulated wearing a weighted scuba-diving belt, which increased their normal body weight by 5%. All subjects walked on the treadmill for 20 minutes per day for 3 days per week for 6 weeks. Improvements in dynamic posturography, falls during balance testing, Berg Balance, UPDRS (Motor Exam), and gait for all groups lead us to believe that neuromuscular regulation can be facilitated in all Parkinson's individuals no matter what treadmill intervention is employed.
Publication
Journal: Amyotrophic lateral sclerosis : official publication of the World Federation of Neurology Research Group on Motor Neuron Diseases
March/8/2010
Abstract
Veterans of the 1990-1991 Gulf War have been reported to have an increased incidence of amyotrophic lateral sclerosis (ALS) compared to personnel who were not deployed. An excess of ALS cases was diagnosed in Gulf War veterans younger than 45 years of age. Increased ALS among Gulf War veterans appears to be an outbreak time-limited to the decade following the Gulf War. Seeking to identify biologically plausible environmental exposures, we have focused on inhalation of cyanobacteria and cyanotoxins carried by dust in the Gulf region, particularly Qatar. Cyanobacterial crusts and mats are widespread in the deserts of Qatar, occupying up to 56% of the available area in some microhabitats. These cyanobacterial crusts, which help bind the desert sands, are dormant throughout most of the year, but during brief spring rains actively photosynthesize. When disturbed by vehicular traffic or other military activities, the dried crusts and mats can produce significant dust. Using HPLC/FD, an amino acid analyzer, UPLC/MS, and triple quadrupole LC/MS/MS we find that the dried crusts and mats contain neurotoxic cyanobacterial toxins, including beta-N-methylamino-L-alanine (BMAA) and 2,4 diaminobutyric acid (DAB). If dust containing cyanobacteria is inhaled, significant exposure to BMAA and other cyanotoxins may occur. We suggest that inhalation of BMAA, DAB, and other aerosolized cyanotoxins may constitute a significant risk factor for the development of ALS and other neurodegenerative diseases.
Publication
Journal: EMBO Journal
May/18/2009
Abstract
Sex in fungi is driven by peptide pheromones sensed through seven-transmembrane pheromone receptors. In Cryptococcus neoformans, sexual reproduction occurs through an outcrossing/heterothallic a- sexual cycle or an inbreeding/homothallic - unisexual mating process. Pheromone receptors encoded by the mating-type locus (MAT) mediate reciprocal pheromone sensing during opposite-sex mating and contribute to but are not essential for unisexual mating. A pheromone receptor-like gene, CPR2, was discovered that is not encoded by MAT and whose expression is induced during a- mating. cpr2 mutants are fertile but have a fusion defect and produce abnormal hyphal structures, whereas CPR2 overexpression elicits unisexual reproduction. When heterologously expressed in Saccharomyces cerevisiae, Cpr2 activates pheromone responses in the absence of any ligand. This constitutive activity results from an unconventional residue, Leu(222), in place of a conserved proline in transmembrane domain six; a Cpr2(L222P) mutant is no longer constitutively active. Cpr2 engages the same G-protein activated signalling cascade as the Ste3a/alpha pheromone receptors, and thereby competes for pathway activation. This study established a new paradigm in which a naturally occurring constitutively active G protein-coupled receptor governs morphogenesis in fungi.
Publication
Journal: Gait and Posture
January/23/2008
Abstract
METHODS
This study was designed as a comparison study of two cohorts.
OBJECTIVE
The hypothesis of this study was that soccer players and dancers have different balance abilities and that these differences could be objectively measured using center of pressure measurements.
BACKGROUND
Center of pressure (COP) measurements are reproducible and have been validated in the literature for assessing standing balance. The literature does not provide sensitive enough techniques for discriminating between two groups of athletes with excellent standing balance.
METHODS
A Matscan pressure mat (Tekscan, Boston, MA) was used to compare COP change variability between 32 female collegiate soccer players and 32 dancers. COP was used to calculate sway index, center acquisition time, sway path length and sway velocity as measures of standing balance.
RESULTS
The dancers had significantly better balance scores (p<0.05) in 5 of 20 balance tests. Results for the remaining 15 balance tests were not significantly different.
CONCLUSIONS
These data show that standing balance characteristics of dancers and soccer players can be objectively measured using COP data. Dancers have certain standing balance abilities that are better than those of soccer players. The COP measurements in this study can be used as a tool in future studies investigating standing balance in different groups of athletes.
Publication
Journal: Zentralblatt fur Bakteriologie. 1. Abt. Originale. A: Medizinische Mikrobiologie, Infektionskrankheiten und Parasitologie
December/17/1980
Abstract
An enzyme-linked-immunosorbent-assay (ELISA) is described for the serodiagnosis of leptospirosis. Using an antigen prepared from a heated culture of a single leptospira strain (Wijnberg) the ELISA is a genusspecific test. The microscopic agglutination test (MAT) served as a reference. ELISA and MAT results agreed in 95% of the sera from 96 leptospirosis patients. One false positive was found in 217 controls. The ELISA is sensitive, specific and relatively easy to perform.
Publication
Journal: Development (Cambridge)
June/15/2003
Abstract
In C. elegans, mutants in the anaphase-promoting complex or cyclosome (APC/C) exhibit defects in germline proliferation, the formation of the vulva and male tail, and the metaphase to anaphase transition of meiosis I. Oocytes lacking APC/C activity can be fertilized but arrest in metaphase of meiosis I and are blocked from further development. To examine the cell cycle and developmental consequences of reducing but not fully depleting APC/C activity, we analyzed defects in embryos and larvae of mat-1/cdc-27 mutants grown at semi-permissive temperatures. Hypomorphic embryos developed to the multicellular stage but were slow to complete meiosis I and displayed aberrant meiotic chromosome separation. More severely affected embryos skipped meiosis II altogether and exhibited striking defects in meiotic exit. These latter embryos failed to produce normal eggshells or establish normal asymmetries prior to the first mitotic division. In developing larvae, extended M-phase delays in late-dividing cell lineages were associated with defects in the morphogenesis of the male tail. This study reveals the importance of dosage-specific mutants in analyzing molecular functions of a ubiquitously functioning protein within different cell types and tissues, and striking correlations between specific abnormalities in cell cycle progression and particular developmental defects.
Publication
Journal: Journal of biomedical materials research. Part A
July/14/2011
Abstract
Porosity has been shown to be a key determinant of the success of tissue engineered scaffolds. A high degree of porosity and an appropriate pore size are necessary to provide adequate space for cell spreading and migration as well as to allow for proper exchange of nutrients and waste between the scaffold and the surrounding environment. Electrospun scaffolds offer an attractive approach for mimicking the natural extracellular matrix (ECM) for tissue engineering applications. The efficacy of electrospinning is likely to depend on the interaction between cells and the geometric features and physicochemical composition of the scaffold. A major problem in electrospinning is the tendency of fibers to accumulate densely, resulting in poor porosity and small pore size. The porosity and pore sizes in the electrospun scaffolds are mainly dependent on the fiber diameter and their packing density. Here we report a method of modulating porosity in three dimensional (3D) scaffolds by simultaneously tuning the fiber diameter and the fiber packing density. Nonwoven poly(ε-caprolactone) mats were formed by electrospinning under various conditions to generate sparse or highly dense micro- and nanofibrous scaffolds and characterized for their physicochemical and biological properties. We found that microfibers with low packing density resulted in improved cell viability, proliferation and infiltration compared to tightly packed scaffolds.
Publication
Journal: Journal of Biomechanics
November/6/2007
Abstract
Hip fracture is rare in young adults, despite evidence that the energy available in a fall is sufficient to fracture the young proximal femur. This might be explained by protective responses that allow young individuals to avoid hip impact during sideways falls. To test this hypothesis, we conducted experiments with 44 individuals (31 women and 13 men) aged 19-26 years, who were instructed to try to maintain balance after a sudden unpredictable sideways translation was applied to the platform they stood upon. While the surface adjacent to the platform was formed of gymnasium mats, we provided no information on surface compliance, or the direction and speed of the perturbation. Ninety percent of participants fell and impacted the pelvis, and 98% of those cases involved direct impact to the hip region. Impact occurred to the hand in 98% of falls, and preceded impact to the pelvis by 50 ms on average (SD=40, range=-12-175 ms). The impact velocity of the pelvis decreased 3.6% for every 10 ms increase in the interval between hand and pelvis impact, and was reduced by 22% on average by stepping prior to impact. Our results suggest that the lack of hip fractures in young adults cannot be explained by avoidance of hip impact during sideways falls. Rather, it probably relates to use of the hands and stepping, and by simply possessing sufficient bone strength to withstand the direct blow to the greater trochanter that tends to accompany sideways falls.
Publication
Journal: Evaluation and Program Planning
October/24/2011
Abstract
Despite growing interest in the use of evidence-based treatment practices, adoption of pharmacotherapies for treating substance use disorders (SUDs) remains modest. Using data from telephone interviews with 250 administrators of publicly funded SUD treatment programs, this study estimated a model of adoption of medication assisted treatment (MAT) for SUDs and examined the relative importance of regulatory, cultural, medical resource, patient-level, and funding barriers to MAT implementation. MAT-adopting programs had significantly greater medical resources, as measured by the employment of physicians and nurses, than non-adopting programs. Administrators of non-adopting programs were asked to rate the importance of 18 barriers to MAT implementation. The most strongly endorsed barriers were regulatory prohibitions due to the program's lack of medical staff, funding barriers to implementing MAT, and lack of access to medical personnel with expertise in delivering MAT. Barriers related to insufficient information about MAT and unsupportive staff attitudes were not widely endorsed. These findings suggest that efforts to promote the implementation of MAT that are inattentive to funding barriers and weaknesses in medical infrastructure may achieve sub-optimal results.
Publication
Journal: Cellular and Molecular Life Sciences
March/22/2009
Abstract
Methionine adenosyltransferases (MATs) are the family of enzymes that synthesize the main biological methyl donor, S-adenosylmethionine. The high sequence conservation among catalytic subunits from bacteria and eukarya preserves key residues that control activity and oligomerization, which is reflected in the protein structure. However, structural differences among complexes with substrates and products have led to proposals of several reaction mechanisms. In parallel, folding studies begin to explain how the three intertwined domains of the catalytic subunit are produced, and to highlight the importance of certain intermediates in attaining the active final conformation. This review analyzes the available structural data and proposes a consensus interpretation that facilitates an understanding of the pathological problems derived from impairment of MAT function. In addition, new research opportunities directed toward clarification of aspects that remain obscure are also identified.
Publication
Journal: Health Services Research
July/2/2003
Abstract
OBJECTIVE
To investigate whether a performance-based contracting (PBC) system provides incentives for nonprofit providers of substance abuse treatment to select less severe clients into treatment.
METHODS
The Maine Addiction Treatment System (MATS) standardized admission and discharge data provided by the Maine Office of Substance Abuse (OSA) for fiscal years 1991-1995, provides demographic, substance abuse, and social functional information on clients of programs receiving public funding.
METHODS
We focused on OSA clients (i.e., those patients whose treatment cost was covered by the funding from OSA) and Medicaid clients in outpatient programs. Clients were identified as being "most severe" or not. We compared the likelihood for OSA clients to be "most severe" before PBC and after PBC using Medicaid clients as the control. Multivariate regression analysis was employed to predict the marginal effect of PBC on the probability of OSA clients being most severe after controlling for other factors.
RESULTS
The percentage of OSA outpatient clients classified as most severe users dropped by 7 percent (p < = 0.001) after the innovation of performance-based contracting compared to the increase of 2 percent for Medicaid clients. The regression results also showed that PBC had a significantly negative marginal effect on the probability of OSA clients being most severe.
CONCLUSIONS
Performance-based contracting gave providers of substance abuse treatment financial incentives to treat less severe OSA clients in order to improve their performance outcomes. Fewer OSA clients with the greatest severity were treated in outpatient programs with the implementation of PBC. These results suggest that regulators, or payers, should evaluate programs comprehensively taking this type of selection behavior into consideration.
Publication
Journal: Cell
June/11/1990
Abstract
The two regulatory pathways appear to come together at the IME1 gene. It is clearly regulated by mating type and induced by starvation as well. Overexpression of IME1 completely overcomes MAT defects but may not circumvent all nutritional control. Kassir et al. (1988) found that overexpression of IME1 allowed sporulation in the presence of glucose and nitrogen. They also have found a meiotic level of message in temperature-sensitive cdc25 diploids shifted to high temperature in rich medium (Simchen and Kassir, 1989). Smith and Mitchell (1989) found that overexpression of IME1 induced an early meiotic event (recombination) in rich medium, but later meiotic events did not occur (i.e., they detected no spore formation). Mitchell (personal communication) has suggested that the difference may be due to differences in the amount of nitrogen present in the two experiments. Thus, while it is clear that IME1 is a necessary positive regulator of meiosis, responding both to mating type and nutritional conditions, it is not clear if it is sufficient. It is possible that other genes are involved in the response to starvation. One interpretation is that a separate nutritional control is exerted for events starting with meiosis I. Much of the regulatory pathway that allows yeast cells to enter meiosis has been determined. As in the case in many sensory transduction pathways, the initial signal for starvation is not yet known, nor is the nature of the proposed downstream phosphorylated effector. Given the power of yeast molecular genetics, answers to both these questions seem attainable. Another area that remains unclear is the difference between responses to nitrogen starvation versus carbon source. Many of the experiments discussed above do not address this question. The strategies used by yeast may be utilized in the developmental decisions used by other, more complex eukaryotes. Certainly several of the gene products involved in nutritional control in yeast have homologies in mammalian systems. For example, the human H-ras gene can substitute for yeast RAS; the relationship is sufficiently close that dominant Ha-ras mutations that inhibit CDC25 have been found (Powers et al., 1989). Furthermore, these dominant Ha-ras mutations have the appropriate phenotype in mammalian cells, suggesting the presence of a CDC25-like protein. Although the major components of mating type control appear to have been defined, the mechanism of the RME1-IME transcriptional control remains to be determined.(ABSTRACT TRUNCATED AT 400 WORDS)
Authors
Publication
Journal: Molecular and Cellular Biology
October/7/1986
Abstract
In the yeast Saccharomyces cerevisiae, haploid cells occur in one of the two cell types, a or alpha. The allele present at the mating type (MAT) locus plays a prominent role in the control of cell type expression. An important consequence of the elaboration of cell type is the ability of cells of one mating type to conjugate with cells of the opposite mating type, resulting in yet a third cell type, an a/alpha diploid. Numerous genes that are involved in the expression of cell type and the conjugation process have been identified by standard genetic techniques. Molecular analysis has shown that expression of several of these genes is subject to control on the transcriptional level by the MAT locus. Two genes, STE7 and STE11, are required for mating in both haploid cell types; ste7 and ste11 mutants are sterile. We report here the molecular cloning of STE7 and STE11 genes and show that expression of these genes is not regulated transcriptionally by the MAT locus. We also have genetically mapped the STE11 gene to chromosome XII, 40 centimorgans from ura4.
Publication
Journal: Science Signaling
April/29/2014
Abstract
The Hippo pathway is a kinase cascade, formed by Hippo, Salvador, Warts, and Mats, that regulates the subcellular distribution and transcriptional activity of Yorkie. Yorkie is a transcriptional coactivator that promotes the expression of genes that inhibit apoptosis and drive cell proliferation. We review recent studies indicating that activity of the Hippo pathway is controlled by cell-cell junctions, cell adhesion molecules, scaffolding proteins, and cytoskeletal proteins, as well as by regulators of apical-basal polarity and extracellular tension.
Publication
Journal: Current Opinion in Microbiology
February/1/2009
Abstract
The mating-type locus (MAT) orchestrates sexual reproduction in fungi. Sexual reproduction is related not only to fitness of an organism, but also correlated with virulence in certain pathogens. In the dandruff-associated fungus Malassesia globosa, although the sexual cycle remains to be discovered, whole genome analysis has led to the hypothesis that mating may occur on host skin. Furthermore, the MAT locus of M. globosa and U. hordei provides evidence that transitions between tetrapolar and bipolar systems have independently occurred. These results, together with studies recapitulating the ancestral tetrapolar mating system in Cryptococcus and the structure of MAT in related smut fungi, have furthered understanding on transitions between different mating systems and the evolution of MAT in the Basidiomycota.
Publication
Journal: Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences
November/18/2002
Abstract
The mammalian phytoestrogens enterodiol (END) and enterolactone (ENL) are produced in the colon by the action of bacteria on the plant precursors matairesinol (MAT), secoisolariciresinol (SECO), their glycosides, and other precursors in the diet. Both END and ENL have been shown to possess weakly estrogenic and antiestrogenic activities, and it has been suggested that the high production of these antiestrogenic mammalian lignans in the gut may serve to protect against breast cancer in women and prostate cancer in men. Various in vitro experiments suggested END and ENL significantly inhibited the growth of human colon tumor cells, and the E2-induced proliferation of MCF-7 breast cancer cells was inhibited by ENL. The protective effects of mammalian lignans may be due to their ability to compete with E2 for the type II estrogen receptor, to induce sex hormone binding globulin (SHBG), to inhibit placental aromatase, and to act as antioxidants. This review mainly deals with the chemistry, quantitative analysis, biological properties and health effects of END and ENL.
Publication
Journal: International Journal of Cancer
October/20/1999
Abstract
Heparanase activity correlates with the metastatic potential of tumor cells. Moreover, the anti-metastatic effect of non-anti-coagulant species of heparin and certain sulfated polysaccharides was attributed to their heparanase-inhibiting activity. We investigated the effect of a chemically sulfated polysaccharide (laminarin), consisting primarily of beta-1,3 glucan (sodium laminarin), and of synthetic phosphorothioate oligodeoxynucleotides, primarily phosphorothioate homopolymer of cytidine (SdC28), on heparanase activity and tumor metastasis. Investigation of the ability of tumor cells to degrade heparan sulfate in intact extracellular matrix revealed that heparanase activity expressed by B16-BL6 mouse melanoma cells and 13762 MAT rat mammary adenocarcinoma cells was effectively inhibited by LS (50% inhibition at 0.2-1 microgram/ml), but there was no inhibition by sodium laminarin up to a concentration of 50 microgram/ml. Complete inhibition of the melanoma heparanase was obtained in the presence of 0.1 microM SdC28. A single i.p. injection of laminarin sulfate, but not of sodium laminarin, before i.v. inoculation of the melanoma or breast-carcinoma cells inhibited the extent of lung colonization by the tumor cells by 80 to 90%. Similar inhibition was exerted by 0.1 microM SdC28. At the effective concentrations, both compounds had a small effect on proliferation of the tumor cells and on growth of the primary tumors in vivo. These results further emphasize the involvement of heparanase in tumor metastasis and the potential clinical application of diverse heparanase-inhibiting molecules such as sulfated polysaccharides and synthetic polyanionic molecules.
Publication
Journal: Seminars in Cell and Developmental Biology
December/18/2012
Abstract
Over the past decade Hippo kinase signalling has been established as an essential tumour suppressor pathway controlling tissue growth in flies and mammals. All members of the Hippo core signalling cassette are conserved from yeast to humans, whereby the yeast analogues of Hippo, Mats and Lats are central components of the mitotic exit network and septation initiation network in budding and fission yeast, respectively. Here, we discuss how far core Hippo signalling components in Drosophila melanogaster and mammals have reported similar mitotic functions as already established for their highly conserved yeast counterparts.
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