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1.
【目的】探讨鳞翅目模式昆虫家蚕Bombyx mori作为重金属污染的监测指示生物在镉胁迫下的酶反应及相关的基因表达。【方法】给家蚕幼虫期全龄添食镉(Cd2+), 调查不同性别家蚕5龄幼虫脂肪体中脂质过氧化物丙二醛(MDA)的含量, 超氧化物歧化酶(SOD)、 过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px)的活性及其基因表达水平的变化。【结果】Cd2+胁迫对雌雄家蚕MDA 含量均具有浓度效应关系, MDA含量随Cd2+胁迫浓度的升高而增加。Cd2+胁迫下, SOD和CAT活性表现为先升后降的变化趋势, Pearson相关性分析显示SOD和CAT活性变化有显著相关性(雄: R=0.770, P=0.001; 雌: R=0.854, P=0.000)。雌性家蚕脂肪体中CAT活性变化和Cat mRNA水平的表达具有正相关性(R=0.712, P=0.003)。雄性家蚕脂肪体中GSH-Px活性随Cd2+胁迫浓度的升高而增加, 显示浓度 效应关系, 12.5~50 mg/kg Cd2+胁迫组GSH-Px活性与对照相比有显著差异(P<0.05), 其活性和GSH-Px mRNA水平的表达具有正相关性(R=0.834, P=0.000); 雌性家蚕脂肪体中GSH-Px活性表现为先升后降的变化趋势, 12.5 mg/kg Cd2+胁迫组GSH-Px活性与对照相比有显著增加(P<0.01)。【结论】结果表明, 急性镉胁迫对家蚕脂肪体有明显的毒性作用, 其作用机制与脂质过氧化加剧和抗氧化酶活性变化有关。家蚕对重金属镉的解毒机制有性别相关性。  相似文献   

2.
研究了不同浓度的重金属Cd2+对泥蚶抗氧化酶活性的影响。设置了四组镉的梯度(0、0.025、0.05和0.1 mg·L-1,分别在第12、24、48、96和144 h对各组织取样,用泥蚶内脏团与鳃制成酶样,对非特异性免疫抗氧化酶SOD、CAT、GST、GPX进行指标测定。结果表明,在开始的12~24 h,中低浓度组SOD酶的活力与对照组相比有显著性地提高,高浓度组SOD酶的活力变化不显著,随着暴露时间的延长和Cd2+浓度的增加,随后至144 h,高中浓度组SOD酶的活力降至低于对照组水平(P<0.05);GPX和GST活力的变化与SOD变化相似,它们的活性在12~48 h的范围内达到顶峰,然后与对照组相比出现显著下降;中低浓度组的CAT酶活力在第144 h时与对照组相比无显著差异(P<0.05)。在一定程度的Cd2+胁迫会对泥蚶体内的抗氧化酶系统造成损伤。  相似文献   

3.
在实验条件下,将健康性成熟雄性长江华溪蟹Sinopotamon yangtsekiense暴露于0、7.25、14.5、29、58和116 mg/L浓度的镉(Cd2+)溶液中,分别于1 d、3 d、5 d和7 d时测定精巢中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、过氧化氧酶(CAT)活性及脂质过氧化产物丙二醛(MDA)的含量.结果显示,不同时间段3种酶活性和MDA含量均具有浓度和时间效应关系,表明急性镉暴露对精巢有明显的毒性作用,其作用机制与抗氧化酶活力变化和脂质过氧化加剧有关.  相似文献   

4.
采用水培方法,研究高浓度镉(0.1 mmol·L-1 Cd2+)、锌(0.15 mmol·L-1 Zn2+)及其复合作用(0.1 mmol·L-1 Cd2++0.15 mmol·L-1Zn2+)对烟草种子的萌发率、幼苗叶片活性氧(ROS)水平、抗氧化物浓度、抗氧化酶活性及膜脂过氧化程度的影响.结果表明: 单因子条件下,与对照相比,高浓度镉、锌处理烟草种子萌发率降低;叶片超氧自由基(O2 )产生速率与过氧化氢(H2O2)含量升高;过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)、脱氢抗化血酸还原酶(DHAR)、单脱氢抗坏血酸还原酶(MDAR)和谷胱甘肽还原酶(GR)活性升高;谷胱甘肽(GSH)含量及其与氧化型谷胱甘肽比值(GSH/GSSG)下降;丙二醛(MDA)含量升高.与镉、锌单因子处理相比,镉、锌复合处理的烟草种子萌发率显著升高;O2 产生速率、H2O2和MDA含量降低;CAT、APX、MDAR活性在处理末期升高.镉、锌胁迫对烟草可造成生理水平上的损伤,且毒性效应随着处理时间的延长而增强.镉、锌复合作用可缓解镉、锌单因子胁迫对烟草幼苗的毒害.  相似文献   

5.
本研究以背角无齿蚌为材料,利用嗜水气单胞菌为诱导刺激物,对背角无齿蚌进行注射感染,在注射后3、6、12 、24、48h分别取血淋巴、肝胰腺,测定其超氧化物歧化酶(SOD)、酚氧化酶 (PO)、酸性磷酸酶 (ACP)、碱性磷酸酶 (AKP) 及过氧化氢酶 (CAT) 的活力,并研究各项酶活力的变化规律。结果表明:除3h肝胰腺外,实验组的SOD活力均不同程度地高于对照组;血清实验组的PO活力开始显著高于对照组,然后降低,而肝胰腺实验组的PO活力持续高于对照组;另外,与对照组相比,实验组中血淋巴与肝胰腺的ACP、AKP和CAT活力在不同的时间段虽然有所增强,但两者之间无显著差异。因此,认为SOD、PO活性可以作为背角无齿蚌免疫抗病功能指标参数,而ACP、AKP及CAT活性能否作为该参数还有待于进一步研究。  相似文献   

6.
目的:探明孕期母体镉暴露对C57BL/6小鼠肝脏和肾脏组织的氧化损伤作用。方法:将45只初始体重相近的孕鼠,于妊娠第7.5 d(E7.5)随机分为3组,饲喂不同浓度的氯化镉溶液(0、20和40 mg/L),分别于E13.5、E16.5和E19.5收集获得各组孕鼠的肝脏和肾脏组织样本,每一妊娠阶段5只孕鼠,检测各组小鼠母体肝脏和肾脏组织抗氧化酶,包括超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GPx)活性,脂质过氧化水平(MDA含量),蛋白质羰基化(PCO含量)和DNA-蛋白质交联(DPC)水平等指标的变化情况。结果:CAT活性在肝脏和肾脏组织中随镉浓度增加逐渐升高,随时间延长逐渐降低;GPx活性在肝脏组织中随时间延长而逐渐降低,而在肾脏组织中随时间延长而逐渐升高;SOD活性在E19.5的40 mg/L镉处理组小鼠肝脏组织中显著升高;PCO含量在肝脏和肾脏组织中随镉浓度增加而逐渐升高;DPC在肝脏和肾脏组织中随镉浓度增加和时间延长而逐渐升高;而MDA含量仅在肝脏组织中随镉浓度增加而逐渐升高,随时间延长而逐渐降低。结论:孕期镉暴露对母体肝脏和肾脏产生了明显的氧化损伤,这可能与镉致胎儿生长受限的毒性效应相关;孕期镉暴露诱导的母体肝脏和肾脏的氧化损伤指标的变化具有组织特异性,这可能与镉在母体肝脏和肾脏中的积累量不同有关。  相似文献   

7.
镉胁迫对大弹涂鱼肝脏黄螵呤氧化酶和抗氧化酶活性的影响   总被引:15,自引:1,他引:14  
研究了不同浓度镉离子对大弹涂鱼肝脏黄嘌呤氧化酶(XOD)、抗氧化酶(超氧化物岐化酶SOD、过氧化氢酶CAT)活性和丙二醛(MDA)含量的影响,以探讨其用于污染暴露的生物标记的可行性.结果表明,低浓度Cd2+(0.05 mg·L-1)暴露使大弹涂鱼肝脏XOD和SOD活性随时间延长升高,第10天达到最大值,中高浓度暴露(0.5 和5 mg·L-1 Cd2+)XOD和SOD活性显著或极显著升高;低和高浓度镉胁迫处理的CAT活性在12 h显著降低,随时间的延长低浓度组CAT活性恢复正常,高浓度组在第7天降到最低值, 并在恢复期的5 d中高浓度组CAT活性却极显著升高;低和中浓度镉胁迫处理的MDA含量12 h极显著升高,而高浓度却极显著下降,随时间延长低浓度恢复正常, 中浓度先上升后下降并到第5天达到最大值,而中高浓度在恢复5 d后MDA含量都极显著降低.  相似文献   

8.
目的:采用半静态毒性实验方法,研究慢性镉暴露对性成熟斑马鱼卵巢组织抗氧化酶活性、脂质过氧化水平的影响及其母源传递毒性效应。方法:依据前期测定的96 h LC50,参考国家渔业标准,设置5个镉处理组(0.058、0.116、0.232、0.580、1.160 mg/L)和1个对照组,镉暴露21 d后,对卵巢组织超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GPx)活性及脂质过氧化物丙二醛(MDA)含量进行测定,并对其受精率、F1代胚胎孵化率及96 hpf幼鱼体长进行统计分析。结果:不同浓度镉暴露均导致卵巢组织SOD、CAT和GPx活性显著降低、MDA含量显著升高并呈浓度依赖效应。子代母源毒性分析显示,与对照组相比,0.232和0.580 mg/L浓度组受精率均显著下降,0.232 mg/L浓度组F1代胚胎孵化率显著降低;各浓度组受精后96 h幼鱼体长与对照组相比有显著性差异,且随着镉浓度的增加体长显著变短。结论:慢性镉暴露导致斑马鱼卵巢组织抗氧化酶活性受到显著抑制,对组织和细胞造成严重氧化损伤,并通过母源传递导致子代发育的毒性效应。  相似文献   

9.
镉胁迫对大蒜苗生理特性的影响及施钙的缓解效应   总被引:3,自引:0,他引:3  
通过营养液水培方式,研究了镉(Cd2+)对大蒜苗生长、光合特性、叶片酶活性及主要矿质元素吸收的影响及增施不同浓度钙(Ca2+)对镉胁迫大蒜苗的缓解效应. 结果表明:与正常生长的大蒜苗相比,施镉能明显降低大蒜苗的形态指标(株高、假茎粗、假茎长及鲜质量),减少叶片的色素含量、净光合速率(Pn)、蒸腾速率(E)及气孔导度(gs),减弱叶片中超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性并增加丙二醛(MDA)含量,减少根中矿质元素(N、P、K、Ca、Mg)含量并增加Cd含量. 增施钙能显著促进镉胁迫大蒜苗的生长,随所增施钙浓度的提高,大蒜苗的形态指标均呈现先增大后减小的趋势,在其浓度为2或3 mmol·L-1时达到峰值;同时,增施钙也可有效提高镉胁迫大蒜叶片的色素含量及光合参数(Pn、E、gs),其变化趋势与形态指标类似,均在所增施钙浓度为2或3 mmol·L-1时最高;另外,增施钙能增强镉胁迫大蒜叶片的抗氧化酶(SOD、POD、CAT)活性并降低MDA含量,还可增加根中矿质元素(N、P、K、Ca、Mg)含量并减少Cd含量,且施钙浓度为2或3 mmol·L-1时效果最好.
  相似文献   

10.
选择黄河上游污染程度较严重的兰州地区和相对无污染的刘家峡地区作为研究样点,比较分析了两地花背蟾蜍(Bufo raddei)肝脏和肾脏中抗氧化酶SOD、CAT和GPx活性及丙二醛(MDA)含量。与刘家峡地区相比,兰州地区花背蟾蜍肝脏的SOD活性升高,CAT和GPx活性极显著降低,肾脏GPx活性显著增高,肝脏和肾脏MDA含量明显高于刘家峡。结果表明,黄河上游环境污染使得花背蟾蜍体内氧化胁迫加重,导致其组织脂质过氧化程度升高。  相似文献   

11.
In 1982, Chisholm et al. used δ13C data for human burials from shell midden sites widely distributed on the coast of British Columbia (BC) to show the extreme dependence of these individuals on high trophic level marine consumers, principally salmon and marine mammals. Here, we present previously unpublished analyses of δ15N for some of the same individuals as well as δ13C data for additional individuals. Nitrogen isotope data show that the diet was dominated by high trophic level marine fauna including carnivorous fish and marine mammals. Although most burials were found in shell middens, marine mollusks made up of only a minor component of diet. The data for δ13C demonstrate that terrestrial faunal foods are undetectable in the diet of the majority of individuals, and seldom constitute more than 10% of the dietary protein of individuals living on the coast although terrestrial fauna were widely available as a potential source of protein. This dietary pattern of exclusion of land‐based animals from their diet persisted for almost 6,000 years along a wide expanse of coastline. In contrast, people from the BC interior (100 km or more from the coast) consumed a mixed diet of terrestrial and marine foods including spawning salmon. Am J Phys Anthropol 155:460–468, 2014. © 2014 Wiley Periodicals, Inc.  相似文献   

12.
This study aimed to analyze the aqueous humor (AH) and the vitreous body (VB) of the eye of the adult frog Rana temporaria L. as a representative species of amphibians, which lead a semi-terrestrial life. The presence of collagen, albumin, uric acid and electron donors was shown in both media; however, there are slight differences in their concentrations. To determine collagen, a spectral-fluorescent probe, cyanine dye, was used. The presence of collagen in AH of the frog was found at the first time. The total content of electron donors (ascorbic and uric acids, tryptophan, and tyrosine) in VB and HA was roughly estimated at ~ 1.5 × 10− 4 mol/L. Both VB and AH absorb light in similar UV regions. The total protein and albumin contents in AH were found to be somewhat higher than those in VB. The uric acid content was at an equally low level in both intraocular media. It is supposed that the similarity of VB and AH compositions shown in this work is due to some exchange between VB and AH contents in the course of accommodation. The role of intraocular fluids in physiological functions of the eye and in protecting the retina against UV light is discussed.  相似文献   

13.
Gorshkova  N. M.  Gorshkova  R. P.  Ivanova  E. P.  Nazarenko  E. L.  Zubkov  V. A. 《Microbiology》2001,70(5):560-563
The sugar analysis of the glycans of the type strains of marine proteobacteria of the genera Pseudoalteromonasand MarinomonasPseudoalteromonas atlanticaIAM12927T, P. aurantiaNCIMB 2033T, P. citreaATCC 29719T, P. elyakoviiKMM 162T, P. espejianaATCC 29659T, P. piscicidaNCIMB 645T, P. tetraodonisIAM 14160T, Marinomonas communisATCC 27118T, and M. vagaATCC 27119T—showed that they contain glucose, galactose, galactosamine, glucosamine, fucose, rhamnose, mannose, heptose, 2-keto-3-deoxyoctonate (KDO), uronic acids, colitose (3,6-dideoxy-L-xylo-hexose), and 6-deoxy-L-talose. The carbohydrate composition of the antigenic polysaccharides (PSs) of P. elyakoviiKMM 162Tand P. espejianaATCC 29659Tdepended on the type and the concentration of carbohydrate substrates in the nutrient media. The molar proportion between rhamnose, glucose, and galactose (ca. 1 : 0.3 : 2) in the PS of P. elyakoviiKMM 162Twas almost the same in the media lacking carbohydrates or containing glucose or galactose at a concentration of 1 g/l. At the same time, the molar proportion between fucose, glucose, galactose, galactosamine, and glucosamine (ca. 1 : 1 : 1 : 2 : 0.5) in the PS of P. espejianaATCC 29659Tdepended on the presence and the concentration of carbohydrate substrates in the medium. A high concentration of glucose in the medium (30 g/l) brought about a rise in the content of glucose in PSs (9-fold for the PS of P. elyakoviiKMM 162Tand 4.6-fold for the PS of P. espejianaATCC 29659T) and led to a decrease in the content of other carbohydrates. The cultivation of these two strains at a lactose concentration of 30 g/l resulted in their PSs containing glucose and galactose in about equal proportions (ca. 1 : 1 in the case of P. espejianaATCC 29659Tand ca. 2.1 : 1.7 in the case of P. elyakoviiKMM 162T).  相似文献   

14.
The systematic position of the North American species of the genusGlyptotendipes is reviewed using morphological characters from all life history stages. The cladistic analysis revealed adult characters which support the monophyly of the three species groups (A, B and C) of PINDER and REISS (1983, 1986) for pupae and larvae. These species groups are given formal subgeneric status, with Group A becomingGlytotendipes, s.s., placingPhytotendipes Goetghebuer, 1937 in synonymy, Group B is namedCaulochironomus (type-species,Tendipes caulicola Kieffer, 1913) and Group C is namedTrichotendipes (type-species,Tendipes signatus Kieffer, 1911).  相似文献   

15.
Summary The gross primary production of periphyton, grown on artificial substrata in the littoral of the Danube, was measured by the light and dark bottle method from April 1970 to March 1971. The periphyton used for the measurements was sampled from various depths, in order to cover the production of the whole littoral. In connection with this, the littoral area was divided into four zones limited by the heights 600 to 200 cm, according to the local water level gauge. The highest localized zone A (500–600 cm) was inundated only at maximum water levels for rather short period of time, the deepest zone D (200–300 cm) was permanently flooded.The zone A showed an average periphyton primary production of 22.5, the zone B of 54.8, the zone C of 28.9 and the zone D of 9.1 mg O2/dm2/day. When recalculated to periods when the individual zones were inundated, the annual production was as follows: in zone A: 0.94, zone B: 9.20, zone C: 7.29 and zone D: 3.06g O2/dm2. The highest primary production was always found in the zone just below the water level. Exceptions occurred only when this zone was inundated for a short time as a result of a temporary rise of the water level and the periphyton was insufficiently developed.In order to compare the values of primary production of periphyton obtained from shallower rivers, where the whole bottom is well illuminated, or from rivers that do not exhibit such frequent and extensive level oscillations as the Danube, average value calculated from results obtained from the zone closest to the water level at the time of measurements, were always used. These results represent a special zone following the water level changes which is called surface zone. Primary periphytic production in the surface zone was 43.8 mg O2/dm2/day. For the annual period it corresponds to the value of 14.74 g O2/dm2. Efficiently of gross photosynthesis in this zone was on the average 1.72%.The height of the water level and the water temperature were higly correlated with gross periphytic production. Close relationships between chlorophyll a concent, biomass and gross primary production of periphyton were found.
Zusammenfassung Die Bruttoprimärproduktion des auf künstlichem Substrat im litoralen Bereich der Donau wachsenden Periphytons, wurde vom April 1970 bis zum März 1971, mit Hilfe der Hell-Dunkelflaschenmethode, gemessen. Das für die Messung herangezogene Periphyton wurde aus verschiedenen Tiefenzonen entnommen, um die Produktion der gesamten Uferzone festzuhalten. Im Zusammenhang damit wurde der litorale Bereich der Donau in 4 Zonen gegliedert, welche ihre Grenzen bei einem Pegelstand von 600–200 cm des Ortspegels hatten. Die höchste Zone A (500–600 cm) wurde nur bei den höchsten Wasserstanden und nur für kurze Zeit vom Wasser überflutet, die tiefste Zone D (200–300 cm) war dauernd unter Wasser.In der Zone A war die durchschnittliche Produktion des Periphytons 22,5 mg O2/dm2/Tag, in Zone B 54,8 mg, in Zone C 28,9 mg und in Zone D 9.1 mg. Nach Berechnung für die Zeit, in der die einzelnen Zonen vom Wasser bedeckt waren war folgende Produktion in den einzelnen Zonen festzustellen: in Zone A 0,94 g O2/dm2, in Zone B 9,20 g, in Zone C 7,29 g und in Zone D 3,06 g. Die höchste Periphytonproduktion wurde jeweils in der Zone festgestellt, welche dem Wasserspiegel am nächsten war. Eine Ausnahme bildeten nur jene Fälle, in denen these Zone nach vorübergehender Erhöhung des Wasserspiegels erst kurze Zeit vom Wasser bedeckt war und das Periphyton ungenügend entwickelt war.Zum Vergleich mit den Werten der Primärproduktion des Aufwuchses aus seichteren Gewässern mit gut belichteter Sohle, oder aus Flüssen welche nicht so häufige und weitreichende Spiegelschwankungen aufweisen wie die Donau, wird in der vorgelegten Arbeit der Durchschnittswert aus den Ergebnissen der Zone verwendet, welche zur Zeit der Messungen dem Wasserspiegel am nächsten war. Diese Ergebnisse repräsentieren eine besondere Zone, welche den Schwankungen des Wasserspiegels folgt und von den Autoren durch den Begriff Oberflachenzone bezeichnet wird. Die Primärproduktion des Periphytons in dieser Oberflächenzone war 43,8 mg O2/dm2/Tag. Dem entspricht im Jahresverlauf ein Wert von 14,74 g O2/dm2. Die Ausnützung der Sonnenenergie war in dieser Zone im Durchschnitt 1,72%.Von den Umweltfaktoren zeigt die Höhe des Wasserspiegels und die Wassertemperatur den engsten Zusammenhang mit der Höhe der Bruttoprimärproduktion des Periphytons. In kürzeren Zeitabschnitten, in denen es zu keinen raschen ausgeprägten Schwankungen des Wasserspiegels des Flusses kommt, wurde eine enge Abhängigkeit zwischen den Werten der Primärproduktion und dem a-Chlorophylgehalt und auch der Biomasse festgestellt.
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16.
Summary 1. The material for this study is drawn from two sources, (a) investigations of the fish fauna in the inner Oslofjord between 1897 and 1967, (b) fish landing statistics available since 1872 at the Oslo fish market.2. The investigations of the fish fauna reveal that 4 species of fish — 2 sharks and 2 arctic bullheads — have disappeared from the deep waters of the Oslofjord where they were known to exist in 1897. We assume that unfavourable conditions, great changes in temperature or lack of oxygen in the stagnant deep water to which these species belonged have been injurious to their propagation and survival.3. The annual fluctuations in the landed quantities of fish are great, but nevertheless there exists a marked decreasing trend since about 1930; total landings in recent years are less than 1/10 of what they were 30 or 40 years ago.4. The fluctuations in the landings of cod, herring and mackerel are studied in some detail. Three periods (of 20 to 22 years' duration) from 1872 to 1932 show increasing average landings of cod: 44, 57, and 74 tons respectively; in the period 1933 to 1955 landings decreased to an average of 16 tons per year. The effect of fluctuating year classes is discussed.5. The landings of herring and mackerel were very good between 1911 and 1919 or 1920 with a maximum of 1500 tons of herring and 800 tons of mackerel. In the following years there was a trend of decrease with a few years of moderately good landings. Mature mackerels are immigrating into the fjord for feeding and spawning, while mature herrings, to a major extent, are supposed to belong to a local stock. The highest landings of both species are due to extremely great catches of young fish, and the success of the fishery in any one year, therefore, dependent of a successful spawning and hatching one ort two years before.6. In conclusion, the attention is drawn to the fact that there are reasons to believe that the profuse growth of bacteria in the polluted waters seems to be injurious to the hatching of fish eggs and to the survival of fish larvae (Dannevig 1945,Oppenheimer 1955).
Veränderungen der Fischfauna und der Fischerei des Oslofjords seit der Jahrhundertwende
Kurzfassung Das Material zu dieser Untersuchung stammt aus zwei Quellen: (a) vier Untersuchungen über die Fischfauna des Oslofjords im Zeitraum zwischen 1897 und 1967, und (b) Statistiken für den Zeitraum von 1872 bis 1964 über die Fischmengen, die im inneren Oslofjord gefangen und an die Fischhalle in Oslo geliefert worden sind. Ein Vergleich der Resultate mit den vier Untersuchungen über die Fischfauna zeigt, daß vier Arten von Tiefwasserfischen aus dem inneren Oslofjord völlig verschwunden sind, nämlichEtmopterus spinax, Somniosus microcephalus, Artediellus uncinatus undIcelus bicornis, die beiden zuletzt genannten wahrscheinlich schon vor 1930. Eine Anzahl anderer Arten, die früher häufig waren, sind jetzt selten. Statistische Erhebungen über die im Oslofjord gefangenen Fische lassen erkennen, daß die Erträge seit den zwanziger und dreißiger Jahren stark zurückgegangen sind. Gleichzeitig hat die Zahl der Fischer abgenommen. Es wird die Schlußfolgerung gezogen, daß die Veränderungen des Oslofjords sich besonders in den letzten 30 Jahren für mehrere Fischarten als schädigend erwiesen haben. Diese Auffassung wird unterstützt durch die Untersuchungen vonDannevig (1945) undOppenheimer (1955), die gezeigt haben, daß die reiche Bakterienflora des Oslofjords für die Entwicklung der pelagischen Fischeier schädlich ist.
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17.
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Abstract

We report here the parallel implementation of an original algorithm allowing a fast calculation of the distance matrix D of a graph representing a given chemical structure (molecule, polymer, crystal, etc.). Our algorithm fits perfectly in the SIMD parallel architecture of the Connection Machines CM-200 as we shall show. After discussing the performances of the parallel evaluation of D, we will end with a relevant application concerning C60 and C70 fullerenes. The present study applies to a generic globally connected graph without any restriction on the local connectivity of each graph's vertex.  相似文献   

20.
Atomic absorption spectrometry is used to determine the contents of microelements (such as Zn, Cu, Ca, Mg and Fe) in the all-blood and hair of the Han, Uygur, and Kazak people in normal health state. The results show that the above mentioned elements in the hair arranged successively as Ca>Zn>Mg>Fe>Cu and those in the all-blood of the Han people arranged as Fe>Mg>Ca>Zn>Cu; of the Uygur and Kazak people, as Fe>Mg>Ca>Zn>Cu. This paper reports that the content of the microelement Mg in the all-blood and hair of the Uygur and Kazak people is obviously higher than that of the Han people (P<0.05).  相似文献   

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