Center for Scientific Research and Higher Education of Ensenada

Ensenada, Mexico

Center for Scientific Research and Higher Education of Ensenada

Ensenada, Mexico
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Killiny N.,University of Florida | Hernandez Martinez R.,Center for Scientific Research and Higher Education of Ensenada | Korsi Dumenyo C.,Tennessee State University | Cooksey D.A.,University of California at Riverside | Almeida R.P.P.,University of California at Berkeley
Molecular Plant-Microbe Interactions | Year: 2013

Exopolysaccharides (EPS) synthesized by plant-pathogenic bacteria are generally essential for virulence. The role of EPS produced by the vector-transmitted bacterium Xylella fastidiosa was investigated by knocking out two genes implicated in the EPS biosynthesis, gumD and gumH. Mutant strains were affected in growth characteristics in vitro, including adhesion to surfaces and biofilm formation. In addition, different assays were used to demonstrate that the mutant strains produced significantly less EPS compared with the wild type. Furthermore, gas chromatography- mass spectrometry showed that both mutant strains did not produce oligosaccharides. Biologically, the mutants were deficient in movement within plants, resulting in an avirulent phenotype. Additionally, mutant strains were affected in transmission by insects: they were very poorly transmitted by and retained within vectors. The gene expression profile indicated upregulation of genes implicated in cell-to-cell signaling and adhesins while downregulation in genes was required for within-plant movement in EPSdeficient strains. These results suggest an essential role for EPS in X. fastidiosa interactions with both plants and insects. © 2013 The American Phytopathological Society.

Muguet J.-B.,University of California at Davis | Lazo J.P.,Center for Scientific Research and Higher Education of Ensenada | Piedrahita R.H.,University of California at Davis
Aquaculture Nutrition | Year: 2011

This study evaluated weaning success of California halibut, Paralichthys californicus, larvae onto a microdiet at various stages of development utilizing growth, survival and digestive enzyme activity. Weaning onto a microdiet was evaluated at 16, 26, 36 and 46days posthatch (dph). Alkaline and acid proteases and leucine aminopeptidase activities were measured after weaning and compared between the weaned treatment and Artemia-fed controls. Survival was significantly lower in the microdiet-fed treatments compared to the control groups. Growth was significantly reduced in all weaning treatments compared to the control, except for the 46dph group. No differences in enzyme activities were detected between treatment and diet at 16 and 26dph; however, activities were higher for the microdiet-fed larvae at 36 and 46dph. This study demonstrates that California halibut larvae possess a differentiated and effective digestive system early in development and can be weaned with relative success (>40% survival) before completion of the metamorphosis (i.e., 36dph). The lack of weaning success at an early date cannot be entirely because of the absence of a functional stomach but could be related to, among other factors, the low-microdiet ingestion rates observed and higher leaching of smaller microdiets. © 2010 Blackwell Publishing Ltd.

Murrieta-Rico F.N.,Center for Scientific Research and Higher Education of Ensenada | Hernandez-Balbuena D.,Autonomous University of Baja California | Petranovskii V.,National Autonomous University of Mexico | Nieto Hipolito J.I.,Autonomous University of Baja California | And 4 more authors.
IEEE International Symposium on Industrial Electronics | Year: 2014

Inertial navigation systems have as sensing elements gyroscopes and accelerometers. The accelerometers with a frequency output domain have some outstanding characteristics like output of quasi-digital signals, high sensitivity, high resolution, wide dynamic range, anti-interference capacity and good stability. This work explains how this sensor works inside an inertial navigation unit and how the measurement of acceleration can be improved through a novel frequency measurement principle. Also it is examined how in a common accelerometer the frequency measurement by principle of rational approximation can be easily implemented with low cost-affordable components. The error analysis in the measurement process is introduced. © 2014 IEEE.

Cox T.E.,CNRS Oceanography Laboratory of Villefranche | Schenone S.,CNRS Oceanography Laboratory of Villefranche | Schenone S.,University of Genoa | Delille J.,CNRS Oceanography Laboratory of Villefranche | And 5 more authors.
Journal of Ecology | Year: 2015

Biological interactions can alter predictions that are based on single-species physiological response. It is known that leaf segments of the seagrass Posidonia oceanica will increase photosynthesis with lowered pH, but it is not clear whether the outcome will be altered when the whole plant and its epiphyte community, with different respiratory and photosynthetic demands, are included. In addition, the effects on the Posidonia epiphyte community have rarely been tested under controlled conditions, at near-future pH levels. In order to better evaluate the effects of pH levels as projected for the upcoming decades on seagrass meadows, shoots of P. oceanica with their associated epiphytes were exposed in the laboratory to three pH levels (ambient: 8.1, 7.7 and 7.3, on the total scale) for 4 weeks. Net productivity, respiration, net calcification and leaf fluorescence were measured on several occasions. At the end of the study, epiphyte community abundance and composition, calcareous mass and crustose coralline algae growth were determined. Finally, photosynthesis vs. irradiance curves (PE) was produced from segments of secondary leaves cleaned of epiphytes and pigments extracted. Posidonia leaf fluorescence and chlorophyll concentrations did not differ between pH treatments. Net productivity of entire shoots and epiphyte-free secondary leaves increased significantly at the lowest pH level yet limited or no stimulation in productivity was observed at the intermediate pH treatment. Under both pH treatments, significant decreases in epiphytic cover were observed, mostly due to the reduction of crustose coralline algae. The loss of the dominant epiphyte producer yet similar photosynthetic response for epiphyte-free secondary leaves and shoots suggests a minimal contribution of epiphytes to shoot productivity under experimental conditions. Synthesis. Observed responses indicate that under future ocean acidification conditions foreseen in the next century an increase in Posidonia productivity is not likely despite the partial loss of epiphytic coralline algae which are competitors for light. A decline in epiphytic cover could, however, reduce the feeding capacity of the meadow for invertebrates. In situ long-term experiments that consider both acidification and warming scenarios are needed to improve ecosystem-level predictions. © 2015 British Ecological Society.

Favela J.,Center for Scientific Research and Higher Education of Ensenada | Castro L.A.,Sonora Institute of Technology | Franco-Marina F.,National Institute of Respiratory Diseases | Sanchez-Garcia S.,National Health Research Institute | And 5 more authors.
Clinical Interventions in Aging | Year: 2013

Objective: To assess whether an intervention based on nurse home visits including alert buttons (NV+AB) is effective in reducing frailty compared to nurse home visits alone (NV-only) and usual care (control group) for older adults. Design: Unblinded, randomized, controlled trial. Setting: Insured population covered by the Mexican Social Security Institute living in the city of Ensenada, Baja California, Mexico. Participants: Patients were aged over 60 years with a frailty index score higher than 0.14. Intervention: After screening and informed consent, participants were allocated randomly to the control, NV+AB, or NV-only groups. Measurements: The primary outcome was the frailty score 9 months later. Quality of life, depression, comorbidities, health status, and health service utilization were also considered. Results: The framing sample included 819 patients. Of those, 591 were not located because they did not have a landline/telephone (341 patients), they had died (107), they were ill (50), or they were not currently living in the city (28). A screening interview was applied to 228 participants, and 57 had a score ≤0.14, 171 had ≥0.14, and 16 refused to complete the baseline questionnaire. A home visit was scheduled for 155 patients. However, 22 did not complete the baseline questionnaire. The final 133 subjects were randomized into the NV+AB (n = 45), NV-only (n = 44), and control (n = 44) groups. There were no statistically significant differences in the baseline characteristics of the groups. The mean age overall was 76.3 years (standard deviation 4.7) and 45% were men. At the baseline, 61.65% were classified as frail. At end of follow-up the adjusted prevalence of frailty in NV+AB group was 23.3% versus 58.3% in the control group. Conclusion: An intervention based on NV+AB seems to have a positive effect on frailty scores. © 2013 Favela et al, publisher and licensee Dove Medical Press Ltd.

Castro L.A.,Sonora Institute of Technology | Favela J.,Center for Scientific Research and Higher Education of Ensenada | Garcia-Pena C.,National Health Research Institute
CIN - Computers Informatics Nursing | Year: 2014

The transition from paper to electronic-based records in the healthcare industry has posed several challenges to conventional medical practices. The introduction of technology in day-to-day medical and nursing practices deserves careful consideration. In this work, we report the results of a controlled experiment to compare nurses' consultation in emergency calls in six different conditions. We studied the effect that the type of communication media (face-to-face, telephone, videoconference) and type of nursing protocol media (paper-based, electronic-based) can have on consultation time, mistakes made, pauses during consultation, eye contact, and efficacy of the consultation. We found that the type of communicationmedia has an effect on consultation time; on average, fewer mistakes were made during telephone-based consultations; for eye contact, there were significantly fewer eye contacts during face-to-face than during videoconference consultations; finally, the type of communication media or protocol media did not have any effect in the efficacy of the consultation. Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Paniagua-Michel J.,CICESE | Olmos-Soto J.,CICESE | Ruiz M.A.,Center for Scientific Research and Higher Education of Ensenada
Methods in Molecular Biology | Year: 2012

The carotenoids, a subfamily of the isoprenoids, are among the most widespread, ancient, diverse, and rich class of all natural products and biomolecules. Microorganisms, as well as microalgae and bacteria synthesize isoprenoids from isopentenyl diphosphate (IPP) and its isomer dimethylallyl diphosphate (DMAPP). For long time, mevalonic acid was assumed to be the only natural precursor for IPP and DMAPP in the cytosolic acetate/mevalonate pathway for the biosynthesis of sterols, sesquiterpenes, triterpenoids, and carotenoids. At present, it is accepted that the relatively new route, the methylerythritol 4-phosphate (MEP), or 1-deoxy-d-xylulose-5-phosphate (DOXP) is the main pathway for the biosynthesis of plastidic isoprenoids, such as carotenoids, phytol (a side chain of chlorophylls), plastoquinone-9, isoprene, mono-, and diterpenes. Cytosolic isoprenoids (sterols) biosynthesized by MEP have been reported in eubacteria and algae (Chlorella, Chlamydomonas, Scenedesmus, and Dunaliella). This review summarizes current knowledge of the biosynthetic pathways leading to the formation of different isoprenoids and carotenoids in bacteria and microalgae. Particular attention was given to the last early steps of the biosynthesis of the key C5-precursor and the final steps of the biosynthesis of carotenoids including selected examples in microalgae and bacteria as well as the recent advances in genomics and metabolic engineering. © 2012 Springer Science+Business Media, LLC.

Cornejo R.,Center for Scientific Research and Higher Education of Ensenada | Tentori M.,Center for Scientific Research and Higher Education of Ensenada | Favela J.,Center for Scientific Research and Higher Education of Ensenada
UbiComp'12 - Proceedings of the 2012 ACM Conference on Ubiquitous Computing | Year: 2012

As SNS become ubiquitous, users are exploiting SNS content to enrich in-person gatherings. In this paper we present the results of a 26-weeks deployment study of an interactive display involving a lightweight Facebook client, and a movement-based social exergame, to explore how this technology impact in-person interactions with one extended family. Our results indicate that the use of the display is semi-public, and catalyzed opportunistic gatherings. We close discussing how the social implications of our results contribute to the use of public social displays, and its social implications for encouraging people to be socially engaged. Copyright 2012 ACM.

Martinez-Montano E.,Center for Scientific Research and Higher Education of Ensenada | Lazo J.P.,Center for Scientific Research and Higher Education of Ensenada
Journal of the World Aquaculture Society | Year: 2012

Digestive capacity varies substantially in marine fish larvae during development, and the formulation of larval diets does not take this into account. The objectives of this study were to assess in vitro protein digestibility of dietary ingredients throughout the ontogeny of digestive system in California halibut, Paralichthys californicus, larvae so as to identify adequate protein sources for each stage of development. Protein digestibility of potential sources was evaluated using the pH-STAT technique. Digestive enzymes utilized for the in vitro assays were obtained from homogenates of whole bodies (9, 15, and 26 days post hatch [dph]) and dissected guts of larvae (39 and 51 dph) sampled at different stages of development. Significant differences in degree of protein hydrolysis (DH) were found among developmental stages for some ingredients. Meals elaborated with rotifers and Artemia showed the highest DH with a tendency to decrease as larval development progressed. Digestibility of casein was poor early in development and increased as it progressed. In contrast, soybean and krill meals were poorly digested throughout development, which may be attributed to differences in the nature or quality of the ingredient. Results from this study highlight the importance of evaluating the digestibility of protein sources through larval development to formulate successful, stage-specific weaning diets. © by the World Aquaculture Society 2012.

PubMed | Center for Scientific Research and Higher Education of Ensenada
Type: Journal Article | Journal: Eukaryotic cell | Year: 2011

We describe the subcellular location of chitin synthase 1 (CHS-1), one of seven chitin synthases in Neurospora crassa. Laser scanning confocal microscopy of growing hyphae showed CHS-1-green fluorescent protein (GFP) localized conspicuously in regions of active wall synthesis, namely, the core of the Spitzenkrper (Spk), the apical cell surface, and developing septa. It was also present in numerous fine particles throughout the cytoplasm plus some large vacuoles in distal hyphal regions. Although the same general subcellular distribution was observed previously for CHS-3 and CHS-6, they did not fully colocalize. Dual labeling showed that the three different chitin synthases were contained in different vesicular compartments, suggesting the existence of a different subpopulation of chitosomes for each CHS. CHS-1-GFP persisted in the Spk during hyphal elongation but disappeared from the septum after its development was completed. Wide-field fluorescence microscopy and total internal reflection fluorescence microscopy revealed subapical clouds of particles, suggestive of chitosomes moving continuously toward the Spk. Benomyl had no effect on CHS-1-GFP localization, indicating that microtubules are not strictly required for CHS trafficking to the hyphal apex. Conversely, actin inhibitors caused severe mislocalization of CHS-1-GFP, indicating that actin plays a major role in the orderly traffic and localization of CHS-1 at the apex.

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