Buenas noches,
Ya tenemos sus calificaciones finales de la materia, las pueden encontrar en la liga adjunta
Valeria me pidió que les comentara que aquellos que tienen 7 o menos pueden optar por NP con lo cual tendrían que repetir la materia, pero podrían mejorar su promedio. Si alguien desea hacerlo, favor de comunicarse conmigo a la brevedad (prácticamente lo que resta de la semana).
Wednesday, December 3, 2014
Monday, October 27, 2014
Lectura 2 - 28 Octubre 2014
The Neolithic revolution of bacterial genomes
Alex Mira, Ravindra Pushker and Francisco Rodríguez-Valera
Before the Neolithic period, human survival was linked to the hunter-gatherer culture and populations were small and scattered. Approximately 10 000 years ago, however, the advent of agriculture and animal husbandry brought the largest social revolution in the history of humankind. Food resources were more abundant and constant, and the human species increased its population size at an extraordinary annual growth rate of 0.1%. From the point of view of bacterial pathogens, humans suddenly became attractive hosts; they concentrated large populations on limited areas, which maximized the chance for transmission between longer-lived carriers. Thus, it is likely that human population growth and expansion during the Neolithic created a selective pressure that favoured pathogens that specialized in human hosts, originating what was probably the first wave of emerging human diseases.
Alex Mira, Ravindra Pushker and Francisco Rodríguez-Valera
Before the Neolithic period, human survival was linked to the hunter-gatherer culture and populations were small and scattered. Approximately 10 000 years ago, however, the advent of agriculture and animal husbandry brought the largest social revolution in the history of humankind. Food resources were more abundant and constant, and the human species increased its population size at an extraordinary annual growth rate of 0.1%. From the point of view of bacterial pathogens, humans suddenly became attractive hosts; they concentrated large populations on limited areas, which maximized the chance for transmission between longer-lived carriers. Thus, it is likely that human population growth and expansion during the Neolithic created a selective pressure that favoured pathogens that specialized in human hosts, originating what was probably the first wave of emerging human diseases.
Lectura 1 - 28 Octubre 2014
The Placenta Harbors a Unique Microbiome
Kjersti Aagaard, JunMa, Kathleen M. Antony, Radhika Ganu, Joseph Petrosino, James Versalovic
Characterizing the processes that govern the establishment of human microbial communities is essential for understanding human development and physiology. Studies have shown that neonates demonstrate complex microbial communities in the gut within the first week of life, with dynamic fluctuations in bacterial composition until a relatively mature equilibrium is reached around 1 to 3 years of age. What shapes these earliest microbial communities, and at what point the infant is first exposed to and colonized by its microbiome, remains unclear. In the first week of life, the full-term neonatal gut microbiome is largely colonized by the phyla Actinobacteria (including Bifidobacterium), Proteobacteria, Bacteroides, and, much less, Firmicutes (including the Lactobacillus spp., which dominate the vaginal flora). In contrast, neonates who weigh <1200 g are dominated by both Firmicutes and Tenericutes phyla, with much less dominance of Actinobacteria. These collective observations raise the possibility that the infant may be first seeded in utero by a common shared low abundance source, such as the placenta, and this seedingmay vary by length of gestation.
Kjersti Aagaard, JunMa, Kathleen M. Antony, Radhika Ganu, Joseph Petrosino, James Versalovic
Characterizing the processes that govern the establishment of human microbial communities is essential for understanding human development and physiology. Studies have shown that neonates demonstrate complex microbial communities in the gut within the first week of life, with dynamic fluctuations in bacterial composition until a relatively mature equilibrium is reached around 1 to 3 years of age. What shapes these earliest microbial communities, and at what point the infant is first exposed to and colonized by its microbiome, remains unclear. In the first week of life, the full-term neonatal gut microbiome is largely colonized by the phyla Actinobacteria (including Bifidobacterium), Proteobacteria, Bacteroides, and, much less, Firmicutes (including the Lactobacillus spp., which dominate the vaginal flora). In contrast, neonates who weigh <1200 g are dominated by both Firmicutes and Tenericutes phyla, with much less dominance of Actinobacteria. These collective observations raise the possibility that the infant may be first seeded in utero by a common shared low abundance source, such as the placenta, and this seedingmay vary by length of gestation.
Monday, October 20, 2014
Lectura 2 - 21 Octubre 2014
Gut Instinct
Do bacteria in the guts of African hunter-gatherers hold the key to a healthier life? An American anthropologist plans to fi nd out
Jop de Vrieze
Jeff Leach hasn’t showered in a month. Living in a small dome tent close to Lake Eyasi in northern Tanzania, he stopped washing one day because he wants to know how that will change the microbial populations in and on his body. Leach is taking daily samples of his own stool and skin, which he carefully stores in a liquid nitrogen tank until they can be shipped to the United States.
Do bacteria in the guts of African hunter-gatherers hold the key to a healthier life? An American anthropologist plans to fi nd out
Jop de Vrieze
Jeff Leach hasn’t showered in a month. Living in a small dome tent close to Lake Eyasi in northern Tanzania, he stopped washing one day because he wants to know how that will change the microbial populations in and on his body. Leach is taking daily samples of his own stool and skin, which he carefully stores in a liquid nitrogen tank until they can be shipped to the United States.
Lectura 1 - 21 Octubre 2014
Antibiotics and Collateral Damage
Alison E. Mather
Most people recognize that antimicrobial drugs are becoming increasingly ineffective, due to the rise of antimicrobial resistance (AMR). The incredible adaptability of microbes and the strong and varied selection pressures to which they are exposed compromise our ability to fight infections, and many common procedures (from hip replacements to cancer therapies) carry greater risks.
Alison E. Mather
Most people recognize that antimicrobial drugs are becoming increasingly ineffective, due to the rise of antimicrobial resistance (AMR). The incredible adaptability of microbes and the strong and varied selection pressures to which they are exposed compromise our ability to fight infections, and many common procedures (from hip replacements to cancer therapies) carry greater risks.
Tuesday, October 14, 2014
Lectura 2 - 14 Octubre 2014
Life at the Poles in the Age of Global Warming: Part 2
Predicting how microorganisms are affected by and could influence global warming proves challenging
Helen A. Vrionis, Lyle G. Whyte, and Robert V. Miller
The strength of sunlight at the poles has a profound impact on the nature and stability of microbial niches. The shallow angle at which sunlight strikes the poles spreads energy over a large area, diminishing its heating power at these latitudes while still driving microbial photosynthesis and primary production. Investigators continue to refıne their projections of how global warming will affect microbial communities at the poles and how these communities, in turn, are likely either to promote or temper those warming trends.
Predicting how microorganisms are affected by and could influence global warming proves challenging
Helen A. Vrionis, Lyle G. Whyte, and Robert V. Miller
The strength of sunlight at the poles has a profound impact on the nature and stability of microbial niches. The shallow angle at which sunlight strikes the poles spreads energy over a large area, diminishing its heating power at these latitudes while still driving microbial photosynthesis and primary production. Investigators continue to refıne their projections of how global warming will affect microbial communities at the poles and how these communities, in turn, are likely either to promote or temper those warming trends.
Lectura 1 - 14 Octubre 2014
Life at the Poles in the Age of Global Warming: Part 1
In responding to climate change, microorganisms at the North and South Poles could have amarked influence on global gas fluxes
Helen A. Vrionis, Robert V. Miller, and Lyle G. Whyte
Polar temperatures, ranging from 5 to 20°C in the summer to 30 to 50°C in winter, slow biochemical reactions, and lead to freezing and thus trapping of approximately one-third of global soil carbon. How this carbon is sequestered, modifıed, released, and cycled depends on geological, environmental, and microbial factors. Here we present an overview, setting the stage for a subsequent feature in which we will describe how polar microbial communities might mitigate large-scale carbon variations.
In responding to climate change, microorganisms at the North and South Poles could have amarked influence on global gas fluxes
Helen A. Vrionis, Robert V. Miller, and Lyle G. Whyte
Polar temperatures, ranging from 5 to 20°C in the summer to 30 to 50°C in winter, slow biochemical reactions, and lead to freezing and thus trapping of approximately one-third of global soil carbon. How this carbon is sequestered, modifıed, released, and cycled depends on geological, environmental, and microbial factors. Here we present an overview, setting the stage for a subsequent feature in which we will describe how polar microbial communities might mitigate large-scale carbon variations.
Monday, October 6, 2014
Lectura 2 - 07 Octubre 2014
The Lifestyle of Vibrio cholerae Fosters Gene Transfers
Growing on chitinous surfaces helps these bacteria to initiate horizontal gene transfer and, perhaps, to swap pathogenic traits
Melanie Blokesch
Waterborne Vibrio cholerae bacteria cause cholera, a pandemic during the last 50 years across Asia, Africa, and Latin America. Although most infected individuals do not develop severe symptoms, some become violently ill with severe diarrhea, vomiting, and cramps, and the loss of body fluids, if untreated, can lead to shock and death.
Growing on chitinous surfaces helps these bacteria to initiate horizontal gene transfer and, perhaps, to swap pathogenic traits
Melanie Blokesch
Waterborne Vibrio cholerae bacteria cause cholera, a pandemic during the last 50 years across Asia, Africa, and Latin America. Although most infected individuals do not develop severe symptoms, some become violently ill with severe diarrhea, vomiting, and cramps, and the loss of body fluids, if untreated, can lead to shock and death.
Lectura 1 - 07 Octubre 2014
Expressing Horizontally Acquired Genes Requires Multitasking
Before taking advantage of foreign genes, bacterial recipients need to overcome their own gene-silencing mechanisms
Irina Artsimovitch
Frequent exchanges of horizontally transferred (HT) DNA shape the evolution of microorganisms, a process affecting an estimated 75% of bacterial genes. Some of those HT genes, particularly those encoding virulence and antibiotic resistance and carried on DNA islands, present a formidable threat to humankind.
Before taking advantage of foreign genes, bacterial recipients need to overcome their own gene-silencing mechanisms
Irina Artsimovitch
Frequent exchanges of horizontally transferred (HT) DNA shape the evolution of microorganisms, a process affecting an estimated 75% of bacterial genes. Some of those HT genes, particularly those encoding virulence and antibiotic resistance and carried on DNA islands, present a formidable threat to humankind.
Thursday, September 18, 2014
Lectura - 23 Septiembre de 2014
Omic Approaches in Microbial Ecology: Charting the Unknown
Analysis of whole-community sequence data is unveiling the diversity and function of specific microbial groups within uncultured phyla and across entire microbial ecosystems
Brett J. Baker and Gregory J. Dick
Nearly a decade ago, Jill Banfıeld of the University of California, Berkeley, and her collaborators applied random shotgun DNA sequencing to microbial biofılms from extremely acidic waters in the Iron Mountain mine in California, assembling genomes for the most abundant of those microbes. Although they relied on Sanger sequencing, whose yields are modest compared to other DNA-sequencing techniques that are now available, their efforts showed that genome sequences could be reconstructed directly from environmental samples, bypassing cultivation while providing insights into the uncultured members of that microbial community.
Analysis of whole-community sequence data is unveiling the diversity and function of specific microbial groups within uncultured phyla and across entire microbial ecosystems
Brett J. Baker and Gregory J. Dick
Nearly a decade ago, Jill Banfıeld of the University of California, Berkeley, and her collaborators applied random shotgun DNA sequencing to microbial biofılms from extremely acidic waters in the Iron Mountain mine in California, assembling genomes for the most abundant of those microbes. Although they relied on Sanger sequencing, whose yields are modest compared to other DNA-sequencing techniques that are now available, their efforts showed that genome sequences could be reconstructed directly from environmental samples, bypassing cultivation while providing insights into the uncultured members of that microbial community.
Tuesday, September 2, 2014
Lectura 2 - 9 Septiembre 2014
Insights into the phylogeny and coding potential of microbial dark matter
Christian Rinke, Patrick Schwientek, Alexander Sczyrba, et al.
Microorganisms are themost diverse and abundant cellular life forms on Earth, occupying every possible metabolic niche. The large majority of these organisms have not been obtained in pure culture and we have only recently become aware of their presence mainly through cultivation-independent molecular surveys based on conservedmarker genes (chiefly small subunit ribosomal RNA; SSU rRNA) or through shotgun sequencing (metagenomics). As an increasing number of environments are deeply sequenced using next-generation technologies, diversity estimates for Bacteria and Archaea continue to rise, with the number of microbial ‘species’ predicted to reach well into the millions.
Christian Rinke, Patrick Schwientek, Alexander Sczyrba, et al.
Microorganisms are themost diverse and abundant cellular life forms on Earth, occupying every possible metabolic niche. The large majority of these organisms have not been obtained in pure culture and we have only recently become aware of their presence mainly through cultivation-independent molecular surveys based on conservedmarker genes (chiefly small subunit ribosomal RNA; SSU rRNA) or through shotgun sequencing (metagenomics). As an increasing number of environments are deeply sequenced using next-generation technologies, diversity estimates for Bacteria and Archaea continue to rise, with the number of microbial ‘species’ predicted to reach well into the millions.
Lectura 1 - 9 Septiembre 2014
Bypassing Cultivation To Identify Bacterial Species
Culture-independent genomic approaches identify credibly distinct clusters,avoid cultivation bias, and provide true insights into microbial species
Luis M. Rodriguez-R and Konstantinos T. Konstantinidis
Whether bacterial species exist as a natural unit remains an unresolved issue, one with important practical challenges, including that of correctly identifying microorganisms and diagnosing the causative agents of microbial diseases. The current bacterial species defınition is based on genetic and phenotypic distinctiveness of organisms grouped under the same name.
Culture-independent genomic approaches identify credibly distinct clusters,avoid cultivation bias, and provide true insights into microbial species
Luis M. Rodriguez-R and Konstantinos T. Konstantinidis
Whether bacterial species exist as a natural unit remains an unresolved issue, one with important practical challenges, including that of correctly identifying microorganisms and diagnosing the causative agents of microbial diseases. The current bacterial species defınition is based on genetic and phenotypic distinctiveness of organisms grouped under the same name.
Sunday, August 31, 2014
Lectura 2 - 2 Septiembre 2014
Making Great Cheeses, Part 2
During affinage, microorganisms gradually ripen cheese to its fully mature state—a process that can take weeks or years
Paul S. Kindstedt
The fırst day of cheese making establishes its chemical composition. During affınage, or fınishing, the unaged cheese is transformed or “ripened” to its fully mature state. Finishing depends on the cheese maker, or affıneur, subjecting the cheese to specifıc environmental conditions and physical manipulations over weeks, months, or even years depending on variety. However, no cheese can mature to greatness unless it begins with the right chemical composition. Here we explore the microbiological, chemical, and environmental conditions during cheese ripening, with well-known cheese varieties as examples.
During affinage, microorganisms gradually ripen cheese to its fully mature state—a process that can take weeks or years
Paul S. Kindstedt
The fırst day of cheese making establishes its chemical composition. During affınage, or fınishing, the unaged cheese is transformed or “ripened” to its fully mature state. Finishing depends on the cheese maker, or affıneur, subjecting the cheese to specifıc environmental conditions and physical manipulations over weeks, months, or even years depending on variety. However, no cheese can mature to greatness unless it begins with the right chemical composition. Here we explore the microbiological, chemical, and environmental conditions during cheese ripening, with well-known cheese varieties as examples.
Lectura 1 - 2 Septiembre 2014
The Making of Great Cheeses
The first steps in making great cheeses involve building the right physical and chemical environment to support microbial ripening
Paul S. Kindstedt
Cheese making transforms milk into either fresh or ripened cheese, with the aging process ranging from weeks to years. The fırst days establish the chemical characteristics of the cheese before it begins to age, setting the stage for microbial ripening. Of the plethora of organisms in new cheese, some remain viable and may proliferate during aging, others will be suppressed, while still others may be suppressed initially and then favored or vice versa, depending on the chemical environment to which they are subject.
The first steps in making great cheeses involve building the right physical and chemical environment to support microbial ripening
Paul S. Kindstedt
Cheese making transforms milk into either fresh or ripened cheese, with the aging process ranging from weeks to years. The fırst days establish the chemical characteristics of the cheese before it begins to age, setting the stage for microbial ripening. Of the plethora of organisms in new cheese, some remain viable and may proliferate during aging, others will be suppressed, while still others may be suppressed initially and then favored or vice versa, depending on the chemical environment to which they are subject.
Tuesday, August 19, 2014
Lectura 2 - 26 Agosto 2014
Cycling Single-Carbon Compounds: from Omics to Novel Concepts
Formerly obscure microbial species emerge as major players in environmental cycling of carbon and nitrogen
Ludmila Chistoserdova, Marina G. Kalyuzhnaya, and Mary E. Lidstrom
We study the bacteria that oxidize methane and potentially other single-carbon compounds in Lake Washington in Seattle. These organisms typically are found in the top layers of the sediment, where they capture the methane that forms following methanogenic degradation of organic matter in the anoxic layers of the sediment, or where they consume other similar single-carbon compounds.
Formerly obscure microbial species emerge as major players in environmental cycling of carbon and nitrogen
Ludmila Chistoserdova, Marina G. Kalyuzhnaya, and Mary E. Lidstrom
We study the bacteria that oxidize methane and potentially other single-carbon compounds in Lake Washington in Seattle. These organisms typically are found in the top layers of the sediment, where they capture the methane that forms following methanogenic degradation of organic matter in the anoxic layers of the sediment, or where they consume other similar single-carbon compounds.
Lectura 1 - 26 Agosto 2014
Bacterial Vesicles in the Ocean
David Scanlan
Biological production of extracellular vesicles is widespread, with vesicles produced by species across all three branches of the tree of life ( 7). In Gram-negative bacteria, vesicles are produced when small regions of the outer membrane bulge away from the cell before pinching off and being released. Biller et al. carefully purifi ed 70 to 100 nmsized membrane-bound extracellular vesicles from exponentially growing Prochlorococcus cells.
David Scanlan
Biological production of extracellular vesicles is widespread, with vesicles produced by species across all three branches of the tree of life ( 7). In Gram-negative bacteria, vesicles are produced when small regions of the outer membrane bulge away from the cell before pinching off and being released. Biller et al. carefully purifi ed 70 to 100 nmsized membrane-bound extracellular vesicles from exponentially growing Prochlorococcus cells.
Tuesday, August 12, 2014
Lectura 2 - 19 de Agosto 2014
Life: is it inevitable or just a fluke?
Nick Lake
Life arose only once on Earth, and if a sample of one were all we had to go on, no grand conclusions could be drawn. But there is more than that. Look at a vital ingredient for life - energy - suggests that simple life is common throughout the universe, but it does nos inevitably evolve into more complex forms such as animals. I might be wrong, but if I'm right, the immense delay between life first appearing on Earth ad the emergence of complex life points to another, very different explanation for why we have yet to discover aliens...
Nick Lake
Life arose only once on Earth, and if a sample of one were all we had to go on, no grand conclusions could be drawn. But there is more than that. Look at a vital ingredient for life - energy - suggests that simple life is common throughout the universe, but it does nos inevitably evolve into more complex forms such as animals. I might be wrong, but if I'm right, the immense delay between life first appearing on Earth ad the emergence of complex life points to another, very different explanation for why we have yet to discover aliens...
Mundane or marvel? (Image: Aires
photography/Getty Images)
Lectura 1 - 19 de Agosto 2014
New Look at Ancient Mineral Could Scrap a Test for Early Oxygen
Richard A. Kerr
Geologists trying to sniff out signs of oxygen in Earth’s early air have long struggled with a major obstacle: eons-old rocks that provide only a ragged, fragmentary record of the gas. Even so, some have for decades taken the presence of the mineral hematite in a so-called banded iron formation (BIF) in northwestern Australia as a sign that 2.5 billion years ago, Earth’s atmosphere had at least a trace of oxygen. The ruddy mineral was thought to record the moment when photo synthesis fi rst pushed oxygen to levels high enough to fully oxidize iron...
Richard A. Kerr
Geologists trying to sniff out signs of oxygen in Earth’s early air have long struggled with a major obstacle: eons-old rocks that provide only a ragged, fragmentary record of the gas. Even so, some have for decades taken the presence of the mineral hematite in a so-called banded iron formation (BIF) in northwestern Australia as a sign that 2.5 billion years ago, Earth’s atmosphere had at least a trace of oxygen. The ruddy mineral was thought to record the moment when photo synthesis fi rst pushed oxygen to levels high enough to fully oxidize iron...
Monday, August 11, 2014
Cómo agregar su ensayo
Parece que ha habido algunas dudas en cuanto a la forma de poner su ensayo. Intentaré explicar de manera breve la manera en que deben hacerlo.
Al final de cada una de las entradas verán algo parecido a esto:
Aquí deben dar en la parte de No comments...
Esto los llevará a una nueva ventana en donde al final podrán observar lo siguiente:
En este recuadro es donde deben poner su ensayo. En la opción de "Comment as:" pueden utilizar cualquiera de las opciones de identificación que les proporciona, sólo no utilicen la opción anonima.
Finalmente envían su ensayo con la opción de "Publish" y se les indicará que no será publicado hasta que lo acepte, lo cual se hará cada martes en que corresponda el artículo.
Espero esto ayude a despejar algunas dudas.
Al final de cada una de las entradas verán algo parecido a esto:
Esto los llevará a una nueva ventana en donde al final podrán observar lo siguiente:
Finalmente envían su ensayo con la opción de "Publish" y se les indicará que no será publicado hasta que lo acepte, lo cual se hará cada martes en que corresponda el artículo.
Espero esto ayude a despejar algunas dudas.
Thursday, August 7, 2014
Lectura Martes 12 de Agosto 2014
Bacterias en Cuatro Ciénegas ¿Qué mensaje encierran?
Gabriela Olmedo, Valeria Souza y Luis E. Eguiarte
En 1999, Valeria y Luis fueron invitados a trabajar en Cuatrociénegas, Coahuila —lugar extraordinario, con cientos de pozas de agua en medio del desierto—, por investigadores de la Universidad Estatal de Arizona, con un proyecto de Astrobiología, financiado por la NASA , dirigido por el Dr. W. Minckley, uno de los más importantes estudiosos de los peces de Norteamérica, y el Dr. Jim Elser, experto en ciclos de nutrientes (particularmente fósforo, elemento central en esta historia) en los cuerpos de agua...
Gabriela Olmedo, Valeria Souza y Luis E. Eguiarte
En 1999, Valeria y Luis fueron invitados a trabajar en Cuatrociénegas, Coahuila —lugar extraordinario, con cientos de pozas de agua en medio del desierto—, por investigadores de la Universidad Estatal de Arizona, con un proyecto de Astrobiología, financiado por la NASA , dirigido por el Dr. W. Minckley, uno de los más importantes estudiosos de los peces de Norteamérica, y el Dr. Jim Elser, experto en ciclos de nutrientes (particularmente fósforo, elemento central en esta historia) en los cuerpos de agua...
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