El descifrado genoma de la manzana la sitúa como la fruta más tentadora

La manzana, la fruta más consumida en el mundo, símbolo de tentación y objeto de seducción acaba de perder un poco más su misterio. Un equipo internacional de científicos de Italia, Francia, Nueva Zelanda, Bélgica y Estados Unidos y Bélgica ha descifrado el primer borrador genético de una de las variedades más comunes de manzana, la «Golden delicious». Los autores han publicado la secuencia genética en la revista «Nature Genetics».
Los genes contienen la información que determina, entre otras cuestiones, la apariencia de la planta, su color, su resistencia o sabor. Por lo que el genoma de la manzana permitirá a los científicos desarrollar variedades más resistentes a la sequía o a temperaturas extremas, ataques de plagas o, incluso, cambiar su sabor o color. Otro objetivo es desarrollar variedades que puedan incrementar sus beneficios saludables. Los cambios se podrán realizar con rapidez porque se sabrá qué característica corresponde a un gen determinado.
Conocer el genoma de la manzana también ha permitido desvelar otro enigma: el origen de esta fruta tan singular. Durante años se ha argumentado a favor y en contra sobre el antepasado de esta moderna y domesticada manzana. La respuesta ya no ofrece ninguna duda. El «tatarabuelo» de esta planta de la familia de las rosáceas es un árbol oriundo de las montañas del sur de Kazakhstán, el «Malus sieversii».

-Los genes del trigo
El genoma de la manzana se suma a otro paso de gigante científico para conocer la secuencia genética del trigo, uno de los pilares de la alimentación. Investigadores británicos publicaron el viernes el primer borrador que permite a científicos y agricultores tener acceso al 95% de los genes del cereal.
Como en la manzana, la información genética permitirá desarrollar variedades más resistentes a enfermedades y climas adversos para mejorar el rendimiento de las plantaciones. Antes se había secuenciado el genoma del arroz y del maíz, más pequeños que el del trigo.

La actriz española Elsa Pataky fan de la macrobiótica

Una larga temporada fue la que la actriz Elsa Pataky pasó el último otoño en la clínica Sha Welness de Altea, el mayor centro macrobiótico de Europa, al que acude gente de todo el mundo para apuntarse a este estilo de vida del que Pataky se ha hecho totalmente adepta.
En lugar de alojarse en un hotel y hacer «vida normal» durante el rodaje del filme «Didi Hollywood», que dirigió Bigas Luna Pataky optó por refugiarse en el Sha y adentrarse en la filosofía de la macrobiótica, que hoy domina a la perfección. Cambió su cuerpo y hasta su mente, y por eso cuantos la tratan saben de cómo habla excelencias sobre este estilo de vida que no ha abandonado un año después.
Es más, durante el rodaje de la última película de Woody Allen, «Midnight París», la española pidió que en el catering le realizaran los platos macrobióticos que ha aprendido a cocinar y cuyas reglas no se salta ya ruede en Francia, en Puerto Rico o donde disponga su trabajo.

**Publicado en "ABC"

Investigan si sustancias de la piel de las ranas servirían para crear nuevos antibióticos

Un equipo de investigadores internacional, liderado por la Universidad de Emiratos Árabes Unidos en Abu Dhabi, ha descubierto en la piel de la rana de patas amarillas de las estribaciones una sustancia que sería capaz de eliminar cepas de bacterias superresistentes a los antibióticos como el 'estafilococo aureo' resistente a la meticilina (SARM), responsable de la mayoría de las neumonías letales originadas en hospitales.

El proyecto, que incluye a investigadores de Japón, Francia y Estados Unidos, entre otros, ha sido presentado durante la 240 Reunión Anual de la Sociedad Química Americana, que se celebra estos días en Boston (Estados Unidos). Entre otros descubrimientos, también han hallado que la rana visón posee en su piel compuestos efectivos frente a la 'bacteria iraquí', muy común entre los soldados occidentales que son heridos en Irak.

"La piel de las ranas es una fuente con un excelente potencial para generar agentes antibióticos", ha explicado uno de los líderes del proyecto, Michael Conlon, bioquímico de la Universidad de Abu Dhabi. En este sentido, los científicos del proyecto analizan en la actualidad las secreciones de la piel de más de 6.000 especies de ranas y han purificado y descrito la estructura química de alrededor de 200 compuestos con potencial antibiótico.

Los investigadores llevan años tratando de aislar estos microbicidas para adaptarlos al consumo humano y crear nuevos medicamentos que sean efectivos contra bacterias, virus y hongos resistentes a los actuales tratamientos. Sin embargo, en la mayoría de las ocasiones, los especialistas se encuentran con que esos compuestos, eficaces contra los microbios, son altamente tóxicos para el ser humano o son destruidos demasiado rápido por el sistema inmune de los mamíferos.

En esta línea, el equipo dirigido por Conlon ha descubierto un nuevo método para reducir esa toxicidad modificando la estructura molecular de estas sustancias, consiguiendo al mismo tiempo aumentar su capacidad como microbicidas. Del mismo modo, los científicos han identificado cómo, bloqueando la acción de ciertas enzimas presentes en el torrente sanguíneo, los componentes de la piel de la rana pueden permanecer más tiempo en el organismo y pueden combatir mejor las infecciones.

--EVITAR NUEVAS RESISTENCIAS

"Las sustancias antibióticas con las que trabajamos utilizan una vía de acción tan poco frecuente que hace muy difícil a los microbios causantes de enfermedades desarrollar resistencias a corto plazo", comenta Conlon. Así, este experto vaticina que los primeros medicamentos basados en los compuestos de la piel de rana podrían entrar en fases de ensayo clínico con humanos en los próximos cinco años.

A este respecto, Conlon prevé que las compañías farmacéuticas podrían desarrollar también con estos químicos nuevas cremas o ungüentos para tratar afecciones cutáneas o fármacos inyectables que ayudaran a superar la resistencia a los tratamientos. Además, apunta, "con estos descubrimientos se ayudará a proteger la biodiversidad, ya que muchas de las ranas con propiedades medicinales viven en hábitats amenazados por la acción del hombre".

**Foto de Pierre Fidenci

Ultra-endurance athletes suffer no cardiac fatigue, even after six days of non-stop exercise

In a research project aimed at understanding the effect of prolonged exercise on the heart, the Karolinska Institutet and the Swedish School of Sport and Health Sciences studied a group of competitors taking part in the Adventure Racing World Championship. The results show no evidence of cardiac fatigue despite the fact that this is a continuous endurance event lasting between five and seven days.
The Adventure Racing World Championship is a true test of endurance. It is held over 800 kilometres of challenging terrain, and competitors have to complete the course non-stop using mountain-biking, trekking, kayaking and in-line skating. The event offered the perfect opportunity to study the unknown effects of the heart’s response to prolonged exercise in conditions of sleep deprivation and energy deficiency. 15 athletes were selected for the study (12 male and 3 female), all of whom had hearts within the normal size range. During the event, they exercised almost continuously for approximately 150 hours, at an average work intensity of 40% (in terms of respective VO2 peak).
Commenting on the study, C. Mikael Mattsson from the Karolinska Institutet said that, “Significant interest is emerging in investigating whether extreme workload damages the heart, or if any measured changes are signs of fatigue, similar to that in skeletal muscle. During ultra-endurance competitions, participants have a constantly elevated heart rate for extreme durations, and a possible risk is that heart muscle cells are catabolised, which could lead to severe pathological conditions.”
If cardiac muscle were to respond in the same way as skeletal muscle, the expectation would be for lower contraction velocities after exercise. However, the results of the study show that this was not the case. It is worth noting that these results are not consistent with other studies of endurance events such as marathons or triathlons. The researchers believe that this may be because average intensity was relatively low despite competitors exercising for extended durations that averaged 150 hours. Therefore, a possible conclusion may be that it is exercise intensity rather than exercise duration that is the primary source for cardiac fatigue.
This study is one element of a wider project to investigate how the heart responds to ultra-endurance exercise. Other aspects of the project will examine the physiological profile of athletes, circulatory response, heart impact and changes in the work of the heart, as a result of, or adaptation to, ultra-endurance exercise.
Research results have provided new insights into the effects of long periods of exercise, typically over six hours. C. Mikael Mattsson notes, “Some athletes experience increased levels of blood markers, which can indicate cardiac damage, yet these levels decrease rapidly and are back to normal within approximately 24 hours. This temporary elevation may not be a result of cardiac damage, but rather as a means of protecting and regulating growth. It also appears that athletes who performed best and felt the strongest during the latter part of the exercise had less-affected hearts.”

**Contributors: C. Mikael Mattsson, Britta Lind, Jonas K. Enqvist, Mattias Mårtensson, Björn Ekblom and Lars-Åke Brodin

Cardiac adaptation in elite female athletes

A study conducted in the UK has established the extent of cardiac adaptation amongst female athletes competing in a number of sports. Previous studies of cardiac adaptation have been conducted only on male athletes, yet a growing number of females participate at elite level in many sports, nowadays including some such as rugby and boxing that were traditionally undertaken only by males. The results show evidence of changes to the heart, particularly to ventricle wall thickness and cavity size. In addition, the study considered whether ethnicity was a factor in the degree of measured cardiac adaptation.
The study was led by Professor Sanjay Sharma, of St. Georges University, London where he is Professor of Cardiology. He is also a member of the ESC’s European Association for Cardiovascular Prevention and Rehabilitation (EACPR), and Medical Director of the London Marathon. “Female athletes do not exhibit the same extent of cardiac adaptation as males. This is because they tend to be smaller and leaner with a lower body mass, and do not reach the same levels of exercise intensity,” he says. “Also, due to the physical differences in chest wall morphology, the typical QRS complexes of females measured on a 12-lead ECG are much less pronounced. The purpose of this study was to determine what changes do occur in elite female athletes that undertake an intensive training regime.”

The study has resulted in four findings:

-Females that engage in regular sport show modest increases in left ventricular wall thickness and cavity size when compared to sedentary females
-The magnitude of left ventricular wall thickness and cavity size is a function of many demographic factors including age and size, as well as the sport undertaken

-In absolute terms, the realistic limits tend to be <11mm>

In order to extend the relevance of the findings to other ethnic groups, the study examined and investigated existing research but discovered that there is limited published data available. One report that compared Caucasian male athletes with African and Afro-Caribbean male athletes suggests that Caucasians have lower left ventricular hypertrophy (LVH) and a lesser prevalence of re-polarisation for very similar group demographics and sporting disciplines.
This finding was confirmed in very important work¹ that was recently published which compared around 200 nationally ranked female athletes from each of these two ethnic groups. Researchers established that black females selected from across 10 sporting disciplines exhibited a greater magnitude of LVH than their white counterparts. 3% of them showed a left ventricle wall thickness of >11mm (typically 12 to 13mm) whereas none of the white athletes exceeded 11mm. 15% of black athletes demonstrated re-polarisation changes compared with just 2% of the white athletes. The study concluded that standardised criteria derived from white athletes could unfairly discriminate against black athletes by leading to unnecessary investigation or even disqualification.

Multivessel and left main disease: indications for surgical and percutaneous intervention

Multivessel and left main disease have been long considered as mainstay indications for coronary artery bypass grafting surgery (CABG). This recommendation, however, has been strongly challenged on several occasions. The release of new Myocardial Revascularisation guidelines by ESC and the European Association of Cardio-Thoracic Surgeons (EACTS) at the ESC Congress on Sunday 29 August is likely to shed new light on what has become a controversial topic.
As recently as 2009, the American College of Cardiology issued its Appropriateness Criteria for Coronary Revascularization document (ACCR) in which both multivessel and left main disease subsets are considered surgical indications – and therefore appropriate for CABG – rather than indications for percutaneous coronary intervention (PCI) using stents. The ACCR document suggests that PCI is inappropriate for left main disease and uncertain for multivessel disease.
Doctor William Wijns of the OLV Hospital in Aalst, Belgium was Co-Chair of the ESC/EACTS Task Force that prepared the new guidelines. He believes that the deep insight gained while reviewing the available evidence and developing the guidelines will give better information and guidance on the issue of when to use CABG and PCI for multivessel and left main disease. “There is some evidence to suggest that we should revisit established practice and review the recommendations contained in the ACCR,” he said. “The new guidelines we have written represent, for the first time, consensus opinion between clinical-non interventional cardiologists, interventional cardiologists and cardiac surgeons.”
The new Myocardial Revascularisation Guidelines are the result of co-operation between the ESC and EACTS. They were written by a Task Force of 25 experts made up of surgeons and cardiologists drawn from both organisations. The Task Force was jointly led by Doctor Wijns and Professor Philippe Kolh of EACTS, and copies of the guidelines can be downloaded at http://authors.escardio.org/guidelines-surveys/esc-guidelines.

Spike in heart disorder hospital admissions raises health care concerns

A growing epidemic of the world’s most common heart rhythm disorder is resulting in an alarming number of hospital admissions in Australia, according to cardiology researchers. A research team led by Christopher Wong, from the University of Adelaide and the Cardiovascular Research Centre at the Royal Adelaide Hospital, found that hospital admissions due to atrial fibrillation had risen by almost 75% in Australia over a 10-year period.
Mr. Wong presented the findings at the European Society of Cardiology’s Scientific Congress in Stockholm, Sweden. The Congress is the largest annual meeting of doctors and scientists in Europe dedicated to the study of cardiovascular disease. “The increasing trend in hospital admissions due to atrial fibrillation is particularly worrying for health care authorities,” Mr. Wong says. “Atrial fibrillation is the most common, sustained heart rhythm disorder in humans, affecting almost one in 10 people over the age of 80. Importantly, left untreated it can have devastating consequences such as stroke and death – one in five strokes are due to this heart rhythm disorder.”
The researchers looked at all hospitalisations due to atrial fibrillation in Australia (population 22 million) over a 10-year period from 1998 to 2008. The 75% increase in hospitalisations was despite a decrease in the length of stay for each admission. “This highlights the fact that not only have the absolute number of admissions increased significantly, but also the percentage of the population hospitalised for atrial fibrillation is continuing to increase at an alarming rate,” Mr. Wong says.
Professor Prashanthan Sanders, an expert on atrial fibrillation and senior author of the study, says the results are a wake-up call for doctors and health care authorities. “There are very few studies that have looked at hospitalisation rates across an entire country due to atrial fibrillation, and none in recent years. This study highlights the enormous public health burden of atrial fibrillation on hospitals and the need for not only better treatments for this increasingly common condition, but also preventative strategies to stop it occurring in the first place,” Professor Sanders says.