Influence of Stocking Rate and Grazing System on Lamb Performance of Mixed Oat and Ryegrass Swards in Uruguay

An experiment was conducted at INIA-Tacuarembó Research Station (Uruguay) during 15 June to 4 October 1998, using a Avena Sativa (oat) and Lolium multiflorum (ryegrass) sward to examine the effect of stocking rate (SR; 25 and 35 lambs/ha) and grazing system (GS; strip and 7 days rotational grazing) on sward and lamb performance. SR had a significant effect on lamb performance, being higher the liveweight gain (LWG; 120 vs 98 g/a/d, P \u3c 0.01), hot carcass weight (HCW; 17.7 vs 16.1 kg/a, P \u3c 0.05) and carcass fat cover (GR; 12 vs 8 mm, P \u3c 0.01) of those lambs managed at the lower SR. At the high SR, lambs increased grazing time (405 vs 376 min., P \u3c 0.05). SG did not affect lamb performance, but strip GS reduces lamb grazing time (367 vs 414 min., P \u3c 0.01) and biting rates (22 vs 24 bites/lamb/min., P \u3c 0.01). Post grazing sward height (SH) was highly associated with LWG (LW = - 101,7 + 32.7 SH – 1.49 SH2, R2 = 0.66). This experiment demonstrated that: (a) the productive potential of ryegrass and oat swards to produce high quality lamb meat, (b) the relative low impact of using strip GS to increase lamb performance and (c) the potential use of post grazing SH as a practical tool to predict lamb LWG in this type of swards

Computational multifocus fluorescence microscopy for three-dimensional visualization of multicellular tumor spheroids

Significance: Three-dimensional (3D) visualization of multicellular tumor spheroids (MCTS) in fluorescence microscopy can rapidly provide qualitative morphological information about the architecture of these cellular aggregates, which can recapitulate key aspects of their in vivo counterpart. Aim: The present work is aimed at overcoming the shallow depth-of-field (DoF) limitation in fluorescence microscopy while achieving 3D visualization of thick biological samples under study. Approach: A custom-built fluorescence microscope with an electrically focus-tunable lens was developed to optically sweep in-depth the structure of MCTS. Acquired multifocus stacks were combined by means of postprocessing algorithms performed in the Fourier domain. Results: Images with relevant characteristics as extended DoF, stereoscopic pairs as well as reconstructed viewpoints of MCTS were obtained without segmentation of the focused regions or estimation of the depth map. The reconstructed images allowed us to observe the 3D morphology of cell aggregates. Conclusions: Computational multifocus fluorescence microscopy can provide 3D visualization in MCTS. This tool is a promising development in assessing the morphological structure of different cellular aggregates while preserving a robust yet simple optical setup

Ep-CAM (MOC-31) expression in tooth germ and ameloblastoma

Ep-CAM, a transmembrane glycoprotein expressed in most epithelium in normal conditions, has diverse roles in these tissues, including in cell adhesion, proliferation, differentiation, cell cycle regulation, migration and intracellular signaling. It is also over-expressed in most malignant neoplasia, participating in the initiation, progression, and metastatic dissemination of the tumor. The expression and roles of this protein in oral neoplasia, particularly in odontogenic tumors, remain unestablished. The objective of this study consisted in analyzing the expression of this protein in ameloblastoma and tooth germ

Violence and Communication

Reseña del libro Violence and Communication, realizada por José María López-Agull&oacute

Risk of Fetal Loss After Chorionic Villus Sampling in Twin Pregnancy Derived from Propensity Score Matching Analysis

Objective: To estimate the risk of fetal loss associated with chorionic villus sampling (CVS) in twin pregnancy, using propensity score analysis. Methods: This was a multicenter cohort study of women with twin pregnancy undergoing ultrasound examination at 11-13 weeks' gestation, performed in eight fetal medicine units in which the leadership were trained at the Harris Birthright Research Centre for Fetal Medicine in London, UK, and in which the protocols for screening, invasive testing and pregnancy management are similar. The risk of death of at least one fetus was compared between pregnancies that had and those that did not have CVS, after propensity score matching (1:1 ratio). This procedure created two comparable groups by balancing the maternal and pregnancy characteristics that lead to CVS being performed, similar to how randomization operates in a randomized clinical trial. Results: The study population of 8581 twin pregnancies included 445 that had CVS. Death of one or two fetuses at any stage during pregnancy occurred in 11.5% (51/445) of pregnancies in the CVS group and in 6.3% (515/8136) in the non-CVS group (P < 0.001). The propensity score algorithm matched 258 cases that had CVS with 258 non-CVS cases; there was at least one fetal loss in 29 (11.2%) cases in the CVS group and in 35 (13.6%) cases in the matched non-CVS group (odds ratio (OR), 0.81; 95% CI, 0.48-1.35; P = 0.415). However, there was a significant interaction between the risk of fetal loss after CVS and the background risk of fetal loss; when the background risk was higher, the risk of fetal loss after CVS decreased (OR, 0.46; 95% CI, 0.23-0.90), while, in pregnancies with a lower background risk of fetal loss, the risk of fetal loss after CVS increased (OR, 2.45; 95% CI, 0.95-7.13). The effects were statistically significantly different (P-value of the interaction = 0.005). For a pregnancy in which the background risk of fetal loss was about 6% (the same as in our non-CVS population), there was no change in the risk of fetal loss after CVS, but, when the background risk was more than 6%, the posterior risk was paradoxically reduced, and when the background risk was less than 6%, the posterior risk increased exponentially; for example, if the background risk of fetal loss was 2.0%, the relative risk was 2.8 and the posterior risk was 5.6%. Conclusion: In twin pregnancy, after accounting for the risk factors that lead to both CVS and spontaneous fetal loss and confining the analysis to pregnancies at lower prior risk, CVS seems to increase the risk of fetal loss by about 3.5% above the patient's background risk. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.info:eu-repo/semantics/publishedVersio

Overview of mathematical approaches used to model bacterial chemotaxis I: the single cell

Mathematical modeling of bacterial chemotaxis systems has been influential and insightful in helping to understand experimental observations. We provide here a comprehensive overview of the range of mathematical approaches used for modeling, within a single bacterium, chemotactic processes caused by changes to external gradients in its environment. Specific areas of the bacterial system which have been studied and modeled are discussed in detail, including the modeling of adaptation in response to attractant gradients, the intracellular phosphorylation cascade, membrane receptor clustering, and spatial modeling of intracellular protein signal transduction. The importance of producing robust models that address adaptation, gain, and sensitivity are also discussed. This review highlights that while mathematical modeling has aided in understanding bacterial chemotaxis on the individual cell scale and guiding experimental design, no single model succeeds in robustly describing all of the basic elements of the cell. We conclude by discussing the importance of this and the future of modeling in this area

Expression of VjbR under Nutrient Limitation Conditions Is Regulated at the Post-Transcriptional Level by Specific Acidic pH Values and Urocanic Acid

VjbR is a LuxR homolog that regulates transcription of many genes including important virulence determinants of the facultative intracellular pathogen Brucella abortus. This transcription factor belongs to a family of regulators that participate in a cell-cell communication process called quorum sensing, which enables bacteria to respond to changes in cell population density by monitoring concentration of self produced autoinducer molecules. Unlike almost all other LuxR-type proteins, VjbR binds to DNA and activates transcription in the absence of any autoinducer signal. To investigate the mechanisms by which Brucella induces VjbR-mediated transcriptional activation, and to determine how inappropriate spatio-temporal expression of the VjbR target genes is prevented, we focused on the study of expression of vjbR itself. By assaying different parameters related to the intracellular lifestyle of Brucella, we identified a restricted set of conditions that triggers VjbR protein expression. Such conditions required the convergence of two signals of different nature: a specific pH value of 5.5 and the presence of urocanic acid, a metabolite involved in the connection between virulence and metabolism of Brucella. In addition, we also observed an urocanic acid, pH-dependent expression of RibH2 and VirB7, two additional intracellular survival-related proteins of Brucella. Analysis of promoter activities and determination of mRNA levels demonstrated that the urocanic acid-dependent mechanisms that induced expression of VjbR, RibH2, and VirB7 act at the post-transcriptional level. Taken together, our findings support a model whereby Brucella induces VjbR-mediated transcription by modulating expression of VjbR in response to specific signals related to the changing environment encountered within the host

Enrichment of trace elements in the clay size fraction of mining soils

Reactive waste dumps with sulfide minerals pro- 14 mote acid mine drainage (AMD), which results in water and 15 soil contamination by metals and metalloids. In these systems, 16 contamination is regulated by many factors, such as mineral- 17 ogical composition of soil and the presence of sorption sites 18 on specific mineral phases. So, the present study dedicates 19 itself to understanding the distribution of trace elements in 20 different size fractions (<2-mm and <2-μm fractions) of min- 21 ing soils and to evaluate the relationship between chemical 22 and mineralogical composition. Cerdeirinha and Penedono, 23 located in Portugal, were the waste dumps under study. The 24 results revealed that the two waste dumps have high degree of 25 contamination by metals and arsenic and that these elements 26 are concentrated in the clay size fraction. Hence, the higher 27 degree of contamination by toxic elements, especially arsenic 28 in Penedono as well as the role of clay minerals, jarosite, and 29 goethite in retaining trace elements has management implica- 30 tions. Such information must be carefully thought in the reha- 31 bilitation projects to be planned for both waste dumps

Histone deacetylases suppress cgg repeat-induced neurodegeneration via transcriptional silencing in models of Fragile X Tremor Ataxia Syndrome

Fragile X Tremor Ataxia Syndrome (FXTAS) is a common inherited neurodegenerative disorder caused by expansion of a CGG trinucleotide repeat in the 59UTR of the fragile X syndrome (FXS) gene, FMR1. The expanded CGG repeat is thought to induce toxicity as RNA, and in FXTAS patients mRNA levels for FMR1 are markedly increased. Despite the critical role of FMR1 mRNA in disease pathogenesis, the basis for the increase in FMR1 mRNA expression is unknown. Here we show that overexpressing any of three histone deacetylases (HDACs 3, 6, or 11) suppresses CGG repeat-induced neurodegeneration in a Drosophila model of FXTAS. This suppression results from selective transcriptional repression of the CGG repeat-containing transgene. These findings led us to evaluate the acetylation state of histones at the human FMR1 locus. In patient-derived lymphoblasts and fibroblasts, we determined by chromatin immunoprecipitation that there is increased acetylation of histones at the FMR1 locus in pre-mutation carriers compared to control or FXS derived cell lines. These epigenetic changes correlate with elevated FMR1 mRNA expression in pre-mutation cell lines. Consistent with this finding, histone acetyltransferase (HAT) inhibitors repress FMR1 mRNA expression to control levels in pre-mutation carrier cell lines and extend lifespan in CGG repeat-expressing Drosophila. These findings support a disease model whereby the CGG repeat expansion in FXTAS promotes chromatin remodeling in cis, which in turn increases expression of the toxic FMR1 mRNA. Moreover, these results provide proof of principle that HAT inhibitors or HDAC activators might be used to selectively repress transcription at the FMR1 locus.open293