企鹅珍珠贝微卫星分子标记的筛选

运用生物素与链霉亲和素的强亲和性原理,用生物素-磁珠吸附微卫星富集法,筛选企鹅珍珠贝(Pteria penguin)的微卫星分子标记序列,进而对南海区企鹅珍珠贝的遗传多样性进行分析。对136个菌落中的85个阳性克隆进行微卫星测序,获得64个序列,达到85.93%。所得到的55个重复6次以上的微卫星序列中,除生物素探针中使用的CA重复外,还得到TG、TC、GA的重复序列。重复序列中完美型36个,占65.5%;不完美型14个,占25.5%;混合型5个,占9.1%。利用Primer Premier5.0设计引物40对,合成其中的20对并进行PCR筛选,15对可扩增出特异性条带。研究表明,筛选出的企鹅珍珠贝微卫星分子标记可用于进一步的遗传多样性分析。     

磁珠富集法筛选西施舌微卫星序列

采用生物素-磁珠吸附微卫星富集法（FIASCO）筛选西施舌（Coelomactra antiquata）微卫星分子标记。结果获得含有重复次数不少于5次的微卫星序列38个,其中完美型占68.4%,非完美型26.3%,混合型5.3%。除探针中使用的CA和GA 2种重复外,还得到ATTG、CGTG和TGTTG的重复序列。微卫星重复次数主要集中在5～46次,最高为70次。利用这些微卫星序列设计了14对引物。该研究筛选出的微卫星标记为进一步研究西施舌的遗传多样性提供帮助。     

云斑尖塘鳢微卫星分子标记的筛选与检测

用磁珠富集法分离云斑尖塘鳢的微卫星序列,由所获得的1032个克隆中筛选出146个阳性克隆,经测序81个含有微卫星序列,52个为完美型,27个为非完美型,2个为复合型,其中43个微卫星序列重复次数在10以上。所获得的云斑尖塘鳢微卫星序列中除探针中使用的CA重复单元和GA重复单元外,还有TAC等其他类型的重复单元。设计合成38对微卫星引物,其中29对引物可稳定扩增出条带,使用这些引物对云斑尖塘鳢48个个体进行检测显示:观测杂合度平均值为0.63,期望杂合度平均值为0.43。29对引物中1对引物表现为单态,7对表现为高度多态,14对表现为中度多态,7对表现为低度多态,多态性较为丰富,说明本研究开发的绝大部分微卫星分子标记较为理想。     

牙鲆基因组 (CAG)n微卫星 DNA 特征分析

通过磁珠富集法筛选牙鲆(Paralichthys olivaceus)的微卫星分子标记,采用限制性内切酶Sau 3A Ⅰ对牙鲆完整基因组DNA进行酶切;通过蔗糖溶液梯度离心,收集400～900 bp大小的片段,连接Brown接头,构建牙鲆基因组文库.用生物素标记的微卫星探针(CAG)15,对基因组文库进行杂交,利用磁珠富集含有微卫星的DNA单链序列,并对其进行PCR扩增;将扩增产物连接到pMD18-T载体后转入感受态大肠杆菌DH5α中,得到微卫星序列文库.利用大量质粒检测法进行二次筛选,成功地从牙鲆基因组中分离出含有CAG重复的微卫星序列,测序其中的3000个单菌落,获得2805个(占93.5%)含有微卫星序列的克隆,其中含有微卫星座位3120个,完美型1808个,占57.97%;非完美型226个,占7.25%;混合型1085个,占34.78%.从中选出186个微卫星序列设计120对引物并合成,经过筛选,74对引物可扩增清晰条带,其中68对呈多态性.     

兰州鲇（CAG）n、（GATA）n微卫星文库构建与鉴定

应用磁珠富集法构建兰州鲇（ Silurus lanzhouensis） CAG重复和GATA重复的微卫星文库,并分析其序列特征。兰州鲇基因组DNA经MseI酶切,选取200～800 bp的片段与生物素标记的探针（CAG）8和（GATA）6杂交,捕获到含有微卫星序列的目的DNA片段连接到pMD19-T载体,转化到大肠杆菌DH5α菌株中构建微卫星富集文库,经PCR检测筛选出阳性克隆进行测序。从126个阳性克隆中随机选取96个进行测序,获得59个微卫星序列（ GenBank登录号： KJ545973～KJ545998, KJ598088～KJ598120）。其中完美型31个（52.54％）、非完美型20个（33.9％）、混合型为8个（13.56％）。根据侧翼序列,成功设计48对引物,选取25对微卫星引物在10个个体进行扩增与多态性筛选,共获得10对多态性引物。结果表明,经优化的磁珠富集法能够高效地获得兰州鲇微卫星标记,这些标记将为兰州鲇种质资源保护、微卫星连锁图谱构建、经济性状的QTL定位及分子标记辅助选育奠定基础。     

磁珠富集法与小片段克隆法筛选鲤微卫星的比较研究

用2种方法克隆黑龙江鲤(Cyprinus(Cyprinus)carpio haonatopterus)的微卫星序列。这2种方法分别是：①经典的小片段DNA克隆库,用末端标记的[γ^-32]ATP的CA重复序列为探针筛选;②将酶切获得的小片段DNA用结合有磁珠的并连接有15个CA重复序列的生物素进行富集,获得的含有CA重复的DNA片段并经过两次PCR扩增再克隆的方法获得富集微卫星片段的克隆库。从前一个方法的克隆库中筛选2000个菌落,获得阳性克隆45个,有22个含有微卫星,完美型的占63．6％,非完美型的占22．7％,混合型的占13．7％,重复次数超过10的有9个,占40．9％;从方法②的克隆库中筛选2600个菌落,获得阳性克隆1300个,测序其中的390个克隆,微卫星314个,完美型的占79．0％;非完美型的占14．3％;混合型的占6．7％,重复次数超过10的有293个,占93．3％。结果表明,用生物素结合磁珠富集法克隆微卫星效率高,成本低,所获微卫星质量高,是一种值得推荐的微卫星制备方法。     

太湖新银鱼微卫星位点的分离与序列特征分析

为了开发太湖新银鱼（Neosalanx taihuensis）的微卫星分子标记,采用生物素标记探针（AC）12、（AAC）10、（AAG）10和（GATA）8对其微卫星位点进行了筛选,并对其序列特征进行了分析。共获得490个微卫星序列,筛选的总效率为78．09％。筛选出725个微卫星位点,其中完美型592个,占81．66％;混合型82个,占11．31％;非完美型51个,占7．03％。探针（AC）12富集到的微卫星重复次数大多集中在14～26次,最高44次;探针（AAC）10和探针（AAG）10富集得到的微卫星重复次数主要集中在8～20次,最高42次;探针（GATA）8富集得到的微卫星重复次数一般在6～15次,最高32次。探针（AC）12、（AAC）10、（AAG）10和（GATA）8的杂交效率分别为85．19％、60．19％、5．16％和10．64％。筛选得到的725个微卫星位点中,二碱基重复位点390个（53．79％）,三碱基重复位点284个（39．17％）,四碱基重复位点47个（6．48％）,五碱基重复位点 1个（0．14％）和六碱基重复位点3 个（0.42％）。根据二碱基重复核心序列进行引物设计,对抚仙湖24尾太湖新银鱼样本进行 PCR 扩增,电泳结果显示部分微卫星位点有较高的多态性,同时本研究获得的三碱基、四碱基、五碱基和六碱基重复位点也可为长重复单元微卫星引物的开发提供基础。     

大黄鱼EST微卫星标记初步筛选

通过构建大黄鱼性腺线性化cDNA文库，并经测序后获得3535条EST，对其二碱基至六碱基重复序列进行筛选，共发现微卫星位点150个，占EST序列的4．24％；其中包括二碱基重复序列64条，三碱基重复序列80条，四碱基重复序列5条，五碱基重复序列1条；三碱基重复序列是最丰富的重复单元，占53．3％。在这些微卫星序列中，（TG／GT／AC／CA）n形式在二碱基重复中最为常见，（GAG／AGG／GGA／CCT）n形式在三碱基重复序列中最为常见，分别占微卫星序列总数的26％和14％。选取其中的62条微卫星序列进行引物设计、合成与多态性检测，经过PCR扩增，2．0％的琼脂糖凝胶电泳检测，获得呈多态性微卫星引物8对，多态率为12．9％。本研究为开发大黄鱼EST微卫星分子标记和大黄鱼基因编码区微卫星的功能研究提供有价值的信息。     

青石斑鱼微卫星DNA 标记的筛选及群体遗传多样性分析

以中国南海海域青石斑鱼（Epinephelus awoara）为材料，构建青石斑鱼小片段部分基因组DNA文库。以M13通用引物和设计合成的微卫星核心序列引物（CA）15,用PCR法对文库进行筛选，共获得96个微卫星序列，分别分布于28个阳性重组克隆中，其中perfect（完美型）共39个（占40．6％），imperfect（非完美型）30个（占31．3％），compound perfect（混合完美型）7个（占7．3％），compound imperfect（混合非完美型）20个（占20．8％）。同时发现（CA／GT）。序列在青石斑鱼的基因组DNA中含量非常丰富。根据微卫星侧翼序列设计28对引物扩增青石斑鱼基因组DNA，有26对引物能扩增出目的片段，选用其中13对多态性稳定的引物对19尾青石斑鱼进行遗传多样性分析。结果显示，13个位点共检测到48个等位基因，平均观测杂合度（Ho）为0．5982，平均期望杂合度（He）为0．5080，平均多态信息含量（PIC）为0．4722，平均Hardy-Weinberg遗传偏离指数（D）为0．1503。实验初步表明中国南海海域青石斑鱼的遗传多样性较为丰富，但在某种程度上受到了人为的干扰。     

日本蟳微卫星富集文库的建立与多态性标记的筛选

采用磁珠富集法筛选日本蟳微卫星分子标记。日本蟳基因组DNA经Sau3 AⅠ酶切后,收集400~1 200 bp大小的片段并纯化,利用生物素标记的寡核苷酸探针(AC)¹⁵从中筛选出含有微卫星序列的DNA片段,连接到pMD18-T载体中,构建富集微卫星序列的基因组文库,经PCR检测筛选出阳性克隆进行测序。从随机挑选的970个菌落中筛选出369个阳性克隆进行测序,结果86.99%(321个)含有微卫星序列,其中完美型占80.54%,非完美型占15.95%,混合型占4.28%。除使用的探针AC重复外,还得到GA、CT等重复序列。共设计出102对微卫星引物,其中65对能扩增出清晰条带,27对具有多态性。同时筛选出的微卫星标记可为今后研究日本蟳的分子遗传育种提供有效的遗传标记。     

Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean

The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.     

Growth performance,digestive enzyme activity and immune response of Japanese sea bass,Lateolabrax japonicus fed with fructooligosaccharide

In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.     

Involvement of gonadal steroids in final oocyte maturation of white perch (Morone americana) and white bass (M. chrysops): in vivo and in vitro studies

Plasma estradiol-17 (E₂), testosterone (T), 17,20-dihydroxy-4-pregnen-3-one (DHP) and 17,20,21-tri-hydroxy-4-pregnen-3-one (20-S) levels were measured by radioimmunoassay (RIA) in white perch (Morone americana) and white bass (M. chrysops) that were induced to undergo final oocyte maturation (FOM) with human chorionic gonadotropin (hCG). Plasma DHP levels increased in females of both species in association with oocyte germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) and decreased thereafter. Plasma 20-S levels also increased with oocyte GVM in white bass, but were several-fold lower than DHP levels. Circulating E₂ and T levels were greatest during GVM and GVBD in both species and decreased to low levels during oocyte hydration and ovulation. Follicles from white perch and white bass which received a priming injection of hCG in vivo, produced both DHP and 20-S in vitro after exposure to hCG and their oocytes underwent GVBD. Ovarian incubates from unprimed fish of either species produced only E₂ and T and their oocytes did not complete GVBD. Oocytes from unprimed bass, but not perch, matured when follicles were exposed to hCG in vitro. Both trilostane and cycloheximide blocked in vitro production of DHP and 20-S and oocyte GVBD by white perch follices. DHP and 20-S were equipotent inducers of FOM in the GVBD bioassay. None of several other structurally-related steroids tested were effective within a physiological range of concentrations. These results indicate a role for DHP and 20-S in the control of FOM in white perch and white bass.     

Cardiac,ventilatory and metabolic responses of two ecologically dissimilar species of fish to waterborne cyanide

Changes in heart rate, ventilatory activity and oxygen consumption were determined in trout (Salmo gairdneri) and brown bullhead catfish (Ictalurus nebulosus) during exposure to a steadily increasing concentration of waterborne cyanide selected to produce death in 8–9 hours for each species. The lethal cyanide concentration for the bullheads was an order of magnitude higher than for trout. Trout developed an immediate and gradually increasing bradycardia throughout the exposure period. Cyanide produced tachycardia in the bullhead followed by a gradual onset of bradycardia as the concentration of cyanide was raised. Pericardial injection of atropine (a muscarinic cholinergic antagonist) indicated that bradycardia in the trout was due initially to increased vagal tone but later due to the direct effect of cyanide on the heart. Hyperventilation in the trout persisted throughout the exposure period, although the rate and amplitude fluctuated and was variable between individual fish. During the last hour of exposure (highest cyanide concentration), ventilation was characterized by rapid, shallow breaths followed by a sudden respiratory arrest. The bullheads exhibited hyperventilation during the first 3 hours of exposure followed by a gradual, linear drop in ventilation rate and amplitude until death occurred. Cardiac and ventilatory responses in both species were attributed to stimulation of central and peripheral chemoreceptors by cyanide. Evidence is presented which suggests the initial response in the bullheads was due, at least in part, to gustatory stimulation by the cyanide. Oxygen consumption of the trout remained above pre-exposure levels for the majority of the test period. Oxygen consumption in the bullhead paralleled the changes in heart and ventilatory rates. Whole-body lactate levels of fingerlings of both species during cyanide exposure were measured to estimate the extent of anaerobiosis. Whole-body lactate levels were much greater in the bullheads than the trout, indicating a higher capacity for anaerobiosis, possibly due to a greater fuel supply. Overall, the trout responded to cyanide in a manner similar to that produced by environmental hypoxia whereas the bullheads experienced a gustatory stimulus which masked the hypoxia-like response.     

An overview of stress physiology of fish transport: changes in water quality as a function of transport duration

This study brings an integrated analysis about the relationship between water deterioration and its physiological consequences in live fish transport. The analysis was focused on the transport water and its deterioration, and physiological challenges imposed on the fish. Usual commercial handling procedures employed to mitigate fish stress during transport were discussed. Future topics of research for the establishment of safer fish transport protocols were proposed. Transport was classified into short (≤8 h) or long transport (>8 h). The main issue in short transports should be the prevention of water pH reduction, while in long transports it is the increase in ammonia. Plasma cortisol is the most employed marker for stress and is acutely elevated upon short episodes of transport, but remains elevated even in long‐transport events. Plasma glucose is perhaps a better marker for handling stress. Plasma lactate, pH, osmolality CO₂ and ions should be more often evaluated. Plasma Na⁺ and Cl^‐ are very useful markers of acidosis, due to their respective exchange for H⁺ and , for acid–base regulation. The establishment of species‐specific transport protocols should be preceded by such combined analyses of water and physiological parameters.     

Are hatchery‐reared abalone naïve of predators? Comparing the behaviours of wild and hatchery‐reared northern abalone,Haliotis kamtschatkana (Jonas, 1845)

Abalone populations have declined worldwide, generating interest in enhancement using hatchery‐reared individuals. In many cases, such restoration efforts have met with limited success due to high predator‐induced mortality rates. Furthermore, the mortality rates of outplanted hatchery abalone are often considerably higher than for wild individuals. This study uses northern abalone (Haliotis kamtschatkana) as a case study to determine whether hatchery‐reared abalone behave differently than their wild counterparts. In the field, outplanted hatchery‐reared abalone were significantly less responsive than wild abalone, in terms of number of abalone responding and intensity of response, to nearby movement and to physical contact with an inert probe. Also, when encountering a cue to which all abalone responded (a seastar predator), hatchery‐reared individuals remained subdued. Anti‐predator behavioural deficits in hatchery‐reared abalone were more pronounced in 4‐year‐old individuals than in 1‐year‐old individuals, suggesting an influence of either age or amount of time spent in the hatchery environment. These behavioural differences are expected to increase the vulnerability of hatchery‐reared abalone to predators, and are likely a major cause of their elevated predator‐induced mortality when outplanted.     

Effects of cadmium on the kinetics of calcium uptake in developing tilapia larvae, Oreochromis mossambicus

The toxic effects of Cd²⁺ on Ca²⁺ influx kinetics in developing tilapia (Oreochromis mossambicus) larvae were evaluated. Addition of 20 µg l^-1 of Cd²⁺ to the environment of 0 and 3 day-old larvae competitively inhibited the Ca²⁺ uptake within 4h resulting in a great increase in K_m values for Ca²⁺ influx (19.3 and 17.4 fold, respectively) as compared with their respective controls. Consequently, the actual Ca²⁺ influx of larvae in solutions of 0.2 mM Ca²⁺ are suppressed by 32–45%. Also, 3 day-old larvae were more sensitive to internally accumulated Cd²⁺ than 0 day-old larvae. Although the Ca²⁺ influx in 0 and 3 day-old larvae may be restored to the levels of their respective controls with 24h of being transferred to a 20 µg l^-1 Cd²⁺ solution, total body Ca²⁺ content was significantly reduced in 3 day-old larvae. Increased Ca²⁺ uptake efficiency ensures sufficient Ca²⁺ for normal growth. However, rapid increase in Ca²⁺ influx after hatching also leads to higher Cd²⁺ uptake. Exposure to Cd²⁺ will lead to a drop in body Ca²⁺ content resulting in retardation of larval growth. Therefore, we conclude that if Ca²⁺ uptake is interfered with at this critical stage of development, larvae will not be able to maintain normal levels of body Ca²⁺ and will show signs of Cd²⁺ poisoning.     

Migratory dynamics of stream-spawning longnose gar (Lepisosteus osseus)

Abstract– Literature evidence suggests that lake-dwelling longnose gar (Lepisosteus osseus) enter tributary streams to spawn, Until the present study, the dynamics of this breeding migration had never been investigated quantitatively. During the summers of 1991 and 1992, longnose gar were captured as they entered Weaubleau Creek, Missouri, a tributary of Harry S. Truman Reservoir. The in-stream spawning migration began in early April and ended in late May, and was positively correlated with stream flow and water level, and negatively correlated with water temperature. In-stream residence times ranged from 15 to 94 days, with males exhibiting longer residence times than females. Once in-stream, longnose gar travelled as far as 10 km upstream and occupied certain pools at greater relative frequencies. Although the reason for this preferential utilization is not completely understood, it may relate to pool depth and riffle proximity. Longnose gar disperse from the spawning stream great distances, with gar captured in Weaubleau Creek being recaptured up to 48 km away. This information should provide fisheries biologists the means to consider the reproductive ecology of this species in their conservation and management decisions.     

Nutritional regulation of hepatocyte fatty acid desaturation and polyunsaturated fatty acid composition in zebrafish (Danio rerio) and tilapia (Oreochromis niloticus)

The desaturation and elongation of [1-¹⁴C]18:3n-3 was investigated in hepatocytes of the tropical warm freshwater species, zebrafish (Danio rerio) and Nile tilapia (Oreochromis niloticus). The hepatocyte fatty acid desaturation/elongation pathway was assayed before and after the fish were fed two experimental diets, a control diet containing fish oil (FO) and a diet containing vegetable oil (VO; a blend of olive, linseed and high oleic acid sunflower oils) for 10 weeks. The VO diet was formulated to provide 1% each of 18:2n-6 and 18:3n-3, and so satisfy the possible EFA requirements of zebrafish and tilapia. At the end of the dietary trial, the lipid and fatty acid composition was determined in whole zebrafish, and liver, white muscle and brain of tilapia. Both zebrafish and tilapia expressed a hepatocyte fatty acid desaturation/elongation pattern consistent with them being freshwater and planktonivorous fish. The data also showed that hepatic fatty acid desaturation/elongation was nutritionally regulated with the activities being higher in fish fed the VO diet compared to fish fed the FO diet. In zebrafish, the main effect of the VO diet was increased fatty acid Δ6 desaturase activity resulting in the production of significantly more 18:4n-3 compared to fish fed the FO diet. In tilapia, all activities in the pathway were greater in fish fed the VO diet resulting in increased amounts of all fatty acids in the pathway, but primarily eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3). However, the fatty acid compositional data indicated that despite increased activity, desaturation of 18:3n-3 was insufficient to maintain tissue proportions of EPA and DHA in fish fed the VO diet at the same level as in fish fed the FO diet. Practically, these results indicate that manipulation of tilapia diets in commercial culture in response to the declining global fish oil market would have important consequences for fish fatty acid composition and the health of consumers. Scientifically, zebrafish and tilapia, both the subject of active genome mapping projects, could be useful models for studies of lipid and fatty acid metabolism at a molecular biological and genetic level. This revised version was published online in August 2006 with corrections to the Cover Date.     

Protein and amino acid composition from the mantle of juvenile O ctopus vulgaris exposed to prolonged starvation

Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg^?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg^?1 protein) than essential amino acids (425.82 ± 9.15 g kg^?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.