Fluid use in mountain bikers - self-reported practices

Background and objectives. Little is known of the fluid replacement habits of participants in mountain bike (MTB) endurance events. This survey set out to determine the current perceptions and practices of this group of endurance athletes. Method. Four hundred and twelve participants in the 3- day 2006 Sani2C (MTB) race completed questionnaires that elicited information regarding their regular fluid intake practices during competitive MTB endurance events. This included their general approach to fluid replacement, their fluid intake practices (type, amount and frequency), urine output and hydration status. Results. While 70% (N = 290) reported that they based their fluid intake practices on personal past experiences, less than half the group (N = 177, 43%) were aware of official sport-specific guidelines. Although 86% (N = 354) reported making use of commercially available sport-specific drinks, consumption of water alone was reported by 34% of respondents (N = 140). The majority (N = 225, 55%) of the mountain bikers reported drinking every 16 - 30 minutes during an endurance ride, while 35% (N = 144) reported drinking every 0 - 15 minutes. Fifty-three per cent (N = 182) of the male respondents and 45% (N = 23) of female respondents reported a routine intake of ≥ 750 ml per hour during endurance rides. This included 2 women who reported regular intakes of between 1 500 and 2 000 ml/hr. Only 7 (2%) reported receiving medical care for dehydration following their participation in previous MTB rides. Conclusions. This survey indicates that although more than half of the mountain bikers did not acknowledge specific awareness of the official fluid replacement guidelines, over 80% reported drinking regularly during a race, and 52% (N = 212) reported a usual intake of ≥ 750 ml/hr during endurance races. Until scientific studies have carefully examined the hydration status and fluid replacement needs of mountain bikers, MTB cyclists are cautioned against the practice of over-hydrating. South African Journal of Sports Medicine Vol. 19 (2) 2007: pp. 52-5

A defensin from tomato with dual function in defense and development

Defensins are antimicrobial peptides that are part of the innate immune system, contributing to the first line of defense against invading pathogens. Defensins and defensin-like peptides are functionally diverse, disrupting microbial membranes and acting as ligands for cellular recognition and signaling. Here we show that the tomato defensin DEF2 is expressed during early flower development. Defensin mRNA abundance, peptide expression and processing are differentially regulated in developing flowers. Antisense suppression or constitutive overexpression of DEF2 reduces pollen viability and seed production. Furthermore, overexpression of DEF2 pleiotropically alters the growth of various organs and enhances foliar resistance to the fungal pathogen Botrytis cinerea. Partially purified extracts from leaves of a DEF2-overexpressing line inhibited tip growth of B. cinerea. Besides providing insights into regulation of defensin expression, these data demonstrate that plant defensins, like their animal counterparts, can assume multiple functions related to defense and development.Peer reviewe