ABSTRACT
Non-structural carbohydrates (NSCs) are critical to maintain plant metabolism under stressful environmental conditions, but we do not fully understand how NSC allocation and utilization from storage varies with stress. While it has become established that storage allocation is unlikely to be a mere overflow process, very little empirical evidence has been produced to support this view, at least not for trees. Here we present the results of an intensively monitored experimental manipulation of whole-tree carbon (C) balance (young Picea abies (L.) H Karst.) using reduced atmospheric [CO2] and drought to reduce C sources. We measured specific C storage pools (glucose, fructose, sucrose, starch) over 21 weeks and converted concentration measurement into fluxes into and out of the storage pool. Continuous labeling ((13)C) allowed us to track C allocation to biomass and non-structural C pools. Net C fluxes into the storage pool occurred mainly when the C balance was positive. Storage pools increased during periods of positive C gain and were reduced under negative C gain. (13)C data showed that C was allocated to storage pools independent of the net flux and even under severe C limitation. Allocation to below-ground tissues was strongest in control trees followed by trees experiencing drought followed by those grown under low [CO2]. Our data suggest that NSC storage has, under the conditions of our experimental manipulation (e.g., strong progressive drought, no above-ground growth), a high allocation priority and cannot be considered an overflow process. While these results also suggest active storage allocation, definitive proof of active plant control of storage in woody plants requires studies involving molecular tools.
Subject(s)
Carbohydrate Metabolism , Carbon Dioxide , Droughts , Picea/metabolism , Stress, Physiological , Biomass , Carbon/analysis , Picea/physiologyABSTRACT
This study evaluated the occurrence of parasitic infections in the "pacu" fish Piaractus mesopotamicus and the "patinga" hybrid (P. mesopotamicus x Piaractus brachypomus) in the northwest of São Paulo State, Brazil. Fish from the following three fish farms were evaluated every two months: A, a hatchery and larviculture farm (n = 16 pacu / n = 19 patinga), B, a growout farm (n = 35 patinga) and C, a fee-fishing property (n = 28 pacu / n = 7 patinga). Thirty-five fish from each property were collected from February 2010 to February 2011 and subjected to parasitological analysis. The parasites found were the following: Mymarothecium viatorum, Anacanthorus penilabiatus, Notozothecium janauachensis (Dactylogyridae, Monogenea),Trichodina spp., Ichthyophthirius multifiliis, Chilodonella sp. (Protozoa), Myxobolus spp.,Henneguya spp. (Myxozoa), Rondonia rondoni, Contracaecum sp. (Nematoda), and Dolops carvalhoi(Crustacea). Of the fish examined, 62.9% from "A" and 100% from "B" and "C" were infested with at least one parasite species. Pacu fish (n = 44) showed a higher susceptibility to Anacanthorus penilabiatus infestations, whereas patinga (n = 61) were more susceptible to Mymarothecium viatorum (p < 0.05). Appropriate fish handling (nutrition, transport and storage), in conjunction with monitoring of water quality, can reduce the stress to which the farmed fish are exposed and is essential for pathogen control.
Este estudo avaliou a ocorrência de infecções parasitárias em pacus Piaractus mesopotamicus e do híbrido patinga (P. mesopotamicus x P. brachypomus) procedentes da região Noroeste do Estado de São Paulo, Brasil. Peixes de três pisciculturas foram avaliados bimestralmente: A - Reprodução e Larvicultura (n = 16 pacus / n = 19 patingas), B-Engorda n = 35 patingas), e C- Pesque-pague (n = 28 pacus / n = 7 patingas). Trinta e cinco peixes de cada propriedade foram coletados de fevereiro de 2010 a fevereiro de 2011, para análises parasitológicas. Os parasitas encontrados foram: Mymarothecium viatorum, Anacanthorus penilabiatus, Notozothecium janauachensis (Dactylogyridae, Monogenea), Trichodina spp., Ichthyophthirius multifiliis, Chilodonella sp. (Protozoa), Myxobolus spp., Henneguya spp. (Myxozoa), Rondonia rondoni, Contracaecum sp. (Nematoda), and Dolops carvalhoi (Crustacea). Dentre os peixes analisados, 62,9% de "A" e 100% de "B" e "C" estavam infectados/infestados por pelo menos uma espécie de parasita. Pacus (n = 44) apresentaram maior suscetibilidade a infestações por Anacanthorus penilabiatus, e patingas (n = 61), por Mymarothecium viatorum (p < 0.05). A profilaxia e cuidados durante o manejo (alimentação, transporte e estocagem), associados ao monitoramento da qualidade de água reduzem o estresse o qual os peixes cultivados estão submetidos, sendo medidas imprescindíveis para o controle de patógenos.
Subject(s)
Animals , Characiformes/parasitology , Fish Diseases/parasitology , Brazil , FisheriesABSTRACT
OBJECTIVES: Fetal mutations and fetal chromosomal abnormalities can be detected by molecular analysis of circulating cell free fetal DNA (ccffDNA) from maternal plasma. This comprehensive study was aimed to investigate and verify blood collection and blood shipping conditions that enable Noninvasive Prenatal Testing. Specifically, the impact of shipping and storage on the stability and concentration of circulating cell-free DNA (ccfDNA) in Streck® Cell-Free DNA™ Blood Collection Tubes (Streck BCTs, Streck, Omaha NE). These BCTs were designed to minimize cellular degradation, and thus effectively prevent dilution of fetal ccf DNA by maternal genomic DNA, was evaluated. DESIGN AND METHODS: Peripheral venous maternal blood was collected into Streck BCTs to investigate four aspects of handling and processing conditions: (1) time from blood draw to plasma processing; (2) storage temperature; (3) mechanical stress; and (4) lot-to-lot tube variations. RESULTS: Maternal blood stored in Streck BCTs for up to 7 days at ambient temperature provides stable concentrations of ccffDNA. The amount of fetal DNA did not change over a broad range of storage temperatures (4°C, 23°C, 37°C, 40°C), but the amount of total (largely maternal) DNA increased in samples stored at 23°C and above, indicating maternal cell degradation and genomic DNA release at elevated temperatures. Shipping maternal blood in Streck BCTs, did not affect sample quality. CONCLUSIONS: Maternal plasma DNA stabilized for 0 to 7 days in Streck BCTs can be used for non-invasive prenatal molecular applications, when temperatures are maintained within the broad parameters assessed in this study.
