底泥中微囊藻复苏和生长特性的研究

研究了微囊藻群体从底泥中释放进入水体的过程及这一过程与水体温度、光照及营养盐的关系 ,并比较了底泥和水体中微囊藻群体的生长特性。同时 ,比较了温度对经低温 (4℃ )处理的和处于对数期的Microcystis.sp .94 0的叶绿素荧光强度的影响。结果表明 ,在 15℃ ,30 μEm-2 s-1光照条件下 ,底泥中的微囊藻群体复苏开始启动 ,并于15d后开始上升到水体中。研究表明 ,存在于底泥中的微囊藻群体从底泥中迁移至上层水体的最适条件为 2 0℃ ,30 μEm-2 s-1。分别培养底泥微囊藻群体和同时期水体中的微囊藻群体 ,研究它们的生长特性 ,发现底泥中的微囊藻群体生长的最适温度为 2 0℃ ,光照强度为 30 μEm-2 s-1,与同期水体中的微囊藻群体生长条件相似。经低温 (4℃ )处理的微囊藻群体和生长周期处于对数期的微囊藻群体叶绿素荧光的影响的实验中 ,作者发现在 2 0℃和 2 5℃时 ,两种经过不同处理的微囊藻群体都随着时间增加而增长。但是 ,在 10℃和 15℃时 ,低温处理的微囊藻群体的叶绿素荧光随着时间增加而增长 ,而处于对数期的微囊藻群体的叶绿素荧光随着时间增加而降低。这表明长期处于低温和黑暗环境中的微囊藻细胞的光系统Ⅱ未受到严重的损伤 ,当环境转变有利于生长时 ,微囊藻细胞的光系统Ⅱ恢复活性。本研究结     

温度、盐度、光照对海洋卡盾藻生长和产毒的影响

在正交试验条件下,分析了盐度、温度、光照强度对海洋卡盾藻生长和产毒的影响.结果表明：在盐度22、33、45和温度20 ℃、25 ℃、30 ℃以及光照强度2000、3000、4500 lx条件下,三因素对海洋卡盾藻生长的影响均不显著,盐度是影响海洋卡盾藻产毒的主要因子;盐度45、温度30 ℃、光照2000 lx下海洋卡盾藻的比生长速率最大,盐度22、温度20 ℃、光照4500 lx下海洋卡盾藻的产毒能力最强;低盐条件不利于海洋卡盾藻的生长,但有利于溶血毒素的合成;当海洋卡盾藻生长受到限制时,其溶血毒素合成增多.     

正交试验法分析环境因子对苦草生长的影响

苦草(Vallisneria natans),是我国长江中下游淡水水体中常见的沉水植物种类。通过室内模拟正交试验的方法,研究不同光照强度、温度和总氮浓度(3光照×3温度×3总氮浓度)对苦草生长的影响。结果表明:(1)苦草在5320lx光照强度、10℃、2—4mg/L水体总氮浓度的条件下生长良好。实验所设100%(12000lx)和50%(5320lx)光照条件下苦草均可正常生长;但对于30℃的高温胁迫耐受性较差;苦草在总氮浓度为4mg/L的水体中各生长指标达到最大值,2mg/L或8mg/L的总氮浓度均会抑制其生长。(2)5320lx的光照强度和10℃的温度对苦草光合色素的合成较为有利;而单纯总氮浓度的变化对苦草光合色素的合成影响不大。(3)苦草的生理活性在高于12000lx或低于1025lx的光强、高于30℃的温度以及8mg/L的总氮浓度下均会受到一定程度的抑制。(4)方差分析结果显示,苦草生长发育的过程中,光照强度和温度是主效环境因子;上述3个环境因子对苦草光合色素的合成均有极显著的影响,并且光强与温度的交互作用对其也有显著影响;光照强度、温度以及这两个环境因子的交互作用为影响苦草生理活性的主效因子。苦草作为不能形成冠层的基生叶莲座型沉水植物,对光强要求不高,对低温的耐受性较好,但较不耐高营养盐浓度,因此,在得到一定修复的富营养化水体中,可以作为秋、冬季水生植物恢复和重建的关键物种。     

绿色微囊藻的混合营养生长

研究绿色微囊藻(Microcystis viridis)在混合条件下的生长特性,以及葡萄糖,光照强度和pH对绿色微囊藻生长的影响。结果表明:绿色微囊藻混合营养生长与光能自养生长相比,生长速率明显提高,对数期延长,生物量显著提高;随着初始葡萄糖浓度在0~18.0g/l范围内增加,同一光照条件下明显提高了藻细胞的生长速率,但在初始葡萄糖浓度18.0~36.0g/l范围内,同一光照条件下葡萄糖浓度的高低对藻细胞的生长速率不再有更大的影响;在光照强度24~112μE·m^-2·s^-1范围内,初始葡萄糖浓度相同条件下藻细胞的生长速率及对葡萄糖的藻体得率都随光照强度的增强而增大,但当光照强度在112~200μE·m^-2·s^-1时,绿色微囊藻的生长速率增加幅度较小,出现了光饱和现象;当pH处于8.0~10.0间,明显促进了绿色微囊藻的生长,偏离该范围越大,越抑制绿色微囊藻的生长,甚至导致死亡。     

温度对外源性32P在水、铜绿微囊藻和底泥中迁移的影响

采用同位素示踪法,在实验室模拟研究不同温度下外源性无机磷酸盐在水、铜绿微囊藻(Microcystis aeruginosa)和底泥中的迁移过程.外源性³²P加入水中后,首先是一种与温度无关的快速物理化学分配,大量溶解性磷酸盐迅速进入底泥和微囊藻中.随后水中³²P的迁移主要受微囊藻生长状况的影响.温度升高有利于微囊藻的生长,并提高了微囊藻吸磷的速度.微囊藻中最大外源性磷浓度只与水环境中的初始磷浓度有关.25℃时铜绿微囊藻的生长曲线有7d的对数期,没有明显的稳定期就转入衰亡期.在25℃时,当微囊藻超积累P到一定程度后,其对数生长同细胞内含P量无关.随着时间的推移,外源性³²P不断向底泥中迁移,实验末期所有的³²P都转移到底泥中.提高温度使水中溶解性外源性磷的下降速率加快,7d后水中溶解的外源性磷浓度低于0.00716mg·L^-1.     

淡水湖泊中微囊藻水华的成因分析

我国藻型富营养化湖泊中一个重要的生物类群是微囊藻,结合国内近几年来对微囊藻形成水华的机制的研究,从微囊藻的结构和生理特点以及环境中温度、光照、pH和营养盐等生态因子综合作用上分析了微囊藻水华的成因。     

温度变化对铜绿微囊藻(Microcystis aeruginosa)生长和光合作用的影响

近年来, 随着水体富营养化的加剧, 在世界各地经常发生微囊藻水华, 并且因有些微囊藻品系能够产生毒素和异味物质, 从而严重影响饮用水安全并威胁人类健康自然水体中的微囊藻水华通常由产毒品系和非产毒品系微囊藻共同引发, 并且很多研究表明气候变暖将使蓝藻水华进一步扩张。研究铜绿微囊藻产毒品系 FACHB-905 (Microcystisaeruginosa FACHB-905)和非产毒品系 FACHB-469 (M. aeruginosa FACHB-469)在不同温度下适应 10 天后的生长、光合作用以及对强光胁迫耐受性的差异。结果发现两品系在 15 ℃ 下都基本没有生长, 在 40 ℃ 下甚至无法存活。而在 20 至 30 ℃间, 两品系的比生长速率均随着培养温度的升高而增大, 当温度进一步升高到 35 , ℃ 其又开始降低。在 20 至 35 ℃ 之间,铜绿微囊藻产毒品系 FACHB-905 比非产毒品系 FACHB-469 的比生长速率略高, 但是尚未达到显著差异水平。在 20 至35 ℃ 下适应 10 天后, 产毒品系 FACHB-905 的最大光合作用速率(Pmax)和暗呼吸速率(Rd)均显著高于非产毒品系 FACHB-469。将两品系转移至强光下(600 μmol·photons·m–2·s–1)照射 4 小时后, 两者的最大光化学效率(Fv/Fm)都显著降低, 但是产毒品系 FACHB-905 的 Fv/Fm 在 30 和 35 ℃ 时显著高于非产毒品系 FACHB-469。总之, 在适应了不同温度梯度 10 天后, 与非产毒品系 FACHB-469 相比, 产毒品系 FACHB-905 表现出较高的生长、光合作用潜能以及耐光性。根据以上研究结果我们推测气候进一步变暖有可能使产毒品系微囊藻处于优势地位, 从而加剧其水华危害。     

温度对外源性^32P在水、铜绿微囊藻和底泥中迁移的影响

采用同位素示踪法,在实验室模拟研究不同温度下外源性无机磷酸盐在水、铜绿微囊藻(Micro-fystis aeruginoas)和底泥中的迁移过程,外源性³²P加入水中后,首先是一种与温度无关的快速物理化学分配,大量溶解性磷酸盐迅速进入底泥和微囊藻中,随后水中³²P的迁移主要受微囊藻生长状况的影响,温度升高有利于微囊藻的生长,并提高了微囊藻吸磷的速度,微囊藻中最大外源性磷浓度只与水环境中的初始磷浓度有关,25℃时铜绿微囊藻的生长曲线有7d的对数期,没有明显的稳定期就转入衰亡期,在25℃时,当微囊藻超积累P到一定程度后,其对数生长同细胞内含P量无关,随着时间的推移,外源性³²P不断向底泥中迁移,实验末期所有的³²P都转移到底泥中,提高温度使水中溶解性外源性磷的下降速率加快,7d后水中溶解的外源性磷浓度低于0．00716mg·L^-1。     

洱海螺旋鱼腥藻生长生理特性的初步研究

近年来,洱海正处于中营养水平向富营养湖泊的过渡阶段,蓝藻水华也频繁发生。本文作者在洱海大规模水华暴发期间,分离、纯化了水华优势种螺旋鱼腥藻,并对其生长生理特性进行了初步研究,以期为探讨洱海鱼腥藻水华发生的环境影响因素提供基础的参考资料。实验结果表明,氮含量1.5mmol/L、磷含量12µmol/L、光照强度30E/ m·s、pH值8－10及温度25℃时,螺旋鱼腥藻生长状况最好,生物量及相对生长速率较高。不同氮、磷浓度下的氮磷代谢活性表明：氮浓度在0－0.36mmol/L时,硝酸还原酶活性随着氮浓度的增加而增强;氮浓度在0.36－6 mmol/L时,酶活性由其生长状况决定,生长越好,酶活性越高。碱性磷酸酶受磷影响较大,随着磷浓度的增加其活性逐渐减弱,磷充足时,氮对其活性并无显著影响。此外,洱海螺旋鱼腥藻可在低的氮、磷浓度下生长,这与其氮磷代谢活性的调节作用有关。     

环境因子对金藻生长和噬藻速率的影响

在微囊藻的大量培养过程中分离到一株能够快速吞噬微囊藻的鞭毛虫-金藻Poterioochromonas sp.,其具有混和营养的特点。研究以人工培养的铜绿微囊藻(Microcystis aeruginosa FACHB469)为饵料,研究了起始饵料浓度、光强、温度和pH等环境因子对Poterioochromonas sp.生长和吞噬饵料速率的影响。结果显示:当无饵料时,金藻的自养生长与光强和温度相关,而与pH无相关性。喂食饵料能显著促进金藻的生长,其吞噬速率和生长速率与起始饵料浓度相关性强,可分别用Michaelis-Menten方程和Monod方程拟合。提供相同量的饵料时,金藻的生长与光强相关性显著,而与温度和pH的相关性不显著;其吞噬速率与pH呈现负相关关系,而与光强和温度相关性不显著。除了在不同pH下的生长外,混合营养时金藻的生长速率与吞噬速率之间存在显著的正相关关系。实验表明适于Poterioochromonas sp.生存并吞噬微囊藻的环境条件较广,这也是进一步探索利用Poterioochromonas sp.控制微囊藻水华的前提。       

Characteristics of the membranes of the pellicle of the ciliatePseudomicrothorax dubius

Summary The membranes of the pellicle of the ciliatePseudomicrothorax dubius are investigated using thin section electron microscopy and freeze-fracture replicas. The plasma membrane is covered by a surface coat and is connected to the outer alveolar membrane by short, sometimes branched, bridges. The inner alveolar membrane is coated on both sides. The epiplasm lies in intimate contact with the cytoplasmic surface of this membrane, and there is a corresponding deposit on the other surface. This deposit is regularly striated.The epiplasmic layer and the alveoli are interrupted at sites of cytotic activity,e.g., the attachment sites of trichocysts, the cytoproct, and the parasomal sacs. The striated deposit ends where the epiplasm ends, indicating a direct relationship between these two epimembranous layers.There is a deposit along the sides of the first part of the tip of the trichocysts, and in this region the trichocyst membrane is free of intramembranous particles.The membrane of the parasomal sacs has a coat on both surfaces. That on the extraplasmic surface is similar to the surface coat of the plasma membrane. The origin of the cytoplasmic coat is unknown. The cytotic activity of these sacs is indicated by their highly irregular profiles.     

The early development of the tail and the transformation of the shape of the nucleus of the spermatid of the domestic fowl,Gallus gallus

Summary The differentiation of the spermatid, especially in reference to the formation of the flagellum, and transformation of the shape of the nucleus was investigated in the domestic fowl.In the early stage of the spermatid, a prominent Golgi apparatus appears around the centrioles. The Golgi vesicles then surround the axial-filament complex which develops from the distal centriole. These vesicles fuse to form continuous membrane at the earliest stage of flagellar formation, and in the succeeding stage Golgi lamellae are attached to the plasma membrane of the developing flagellum. From these observations, it is assumed that Golgi apparatus may be a source of the membrane system of the flagellum.The microtubules distributed around the nucleus form the circular manchette. The anterior region of the nucleus with the manchette is cylindrical in shape and the posterior region without it remains irregular in shape. When the circular manchette has been completed, the whole nucleus acquires a slender cylindrical shape. The circular manchette then changes into the longitudinal manchette. The nuclei of spermatids without a longitudinal manchette are abnormal in shape. In view of these observations it is assumed that the nuclear shaping of the spermatid may be accomplished by circular manchette and the maintenance of shape of the elongated nucleus by longitudinal manchette.The authors wish to thank Mr. Takayuki Mori for his helpful suggestions and technical advices     

Characterization of the composition of the aqueous humor and the vitreous body of the eye of the frog Rana temporaria L

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.     

Observations on the permeability of the choriocapillaris of the eye

Summary The choriocapillaris is a fenestrated capillary bed located posterior to the retinal pigment epithelium. It serves as the main source of supply to the photoreceptors, retinal pigment epithelium, and other cells of the outer retina. The permeability of these capillaries to intravenously injected ferritin (MW — approx. 480,000; mol. diam. 11 nm) was examined in the mouse, rabbit, and guinea pig, each of which is characterized by a different type of retinal vascularization. In all three species, the bulk of the ferritin remained in the capillary lumina, where it appeared to be blocked at the level of the diaphragmed fenestrae. Some ferritin was present in endothelial cell vacuoles. The results confirm previous work on the rat choriocapillaris and indicate that the barrier function of the choriocapillary endothelium is present even among species in which the retinal circulation differs significantly.Supported by NIH grant EY03418