CHANGES IN LEVELS OF PYRIDINE NUCLEOTIDES IN CHLORELLA CELLS DURING THE COURSE OF PHOTOSYNTHESIS

1. Using intact cells of Chlorella, the effects of CO₂ on thelevelsof oxidized and reduced forms of DPN and TPN in the lightandin the dark were investigated.
2. It was found that the light-inducedchanges of the DPNH-levelwere not affected by the presenceor absence of CO₂. On theother hand, the light-induced increaseof TPNH was suppressedin the presence of CO₂ and the levelof TPNH which was raisedon illumination in the absence of CO₂was lowered by the provisionof CO₂.
3. On the basis of thesefindings, it was concluded that TPNH,but not DPNH, is participating,in some way, in the mechanismof photosynthesis.
4. Discussionswere made on the difference in the sites of participationofTPNH and of the photogenic reducing agent (R) in the pathofcarbon in photosynthesis.

(Received February 28, 1960; )     

CHANGES IN ACTIVITIES OF THYMIDYLATE SYNTHASE AND DIHYDROFOLATE REDUCTASE IN SEA URCHIN EGGS AFTER FERTILIZATION

Thymidylate synthase activity in sea urchin eggs increases just after fertilization and decreases 30 min later. Then, cyclic variation in the activity occurs in association with the cleavage cycle. Dihydrofolate reductase activity in fertilized eggs is almost the same as in unfertilized eggs and shows no marked change within 3 hr after fertilization. Aminopterin, an analogue of dihydrofolate, inhibits dihydrofolate reductase, and arrests cleavage. On incubation in sea water containing aminopterin (20-100μM) from the time of fertilization, the development of Clypeaster and Pseudocentrotus eggs was arrested at the 32–64 cell stage, and that of Anthocidaris eggs was arrested at the morula stage. Dihydrofolate (100μM) counteracts the inhibitory effect of aminopterin on egg cleavage. Thymidine at concentrations above 10μM also prevents inhibition by aminopterin. Other deoxyribonucleosides at concentrations of 10μM to 100μM do not affect inhibition of egg cleavage by aminopterin. Deoxyadenosine at concentrations above 5 mM inhibits egg cleavage, but other deoxyribonucleosides have no effect.     

BLUE LIGHT IN THE DEVELOPMENT OF FERN GAMETOPHYTES AND ITS INTERACTION WITH FAR-RED AND RED LIGHT

Two effects of blue light on the development of Onoclea sensibilis spores are demonstrated. Brief irradiation promotes the protonemal or filamentous type of growth, and the rate of filament elongation is greater than in darkness. Longer periods of irradiation induce the formation of 2-dimensional prothallia. Blue-light treatments which promote filament elongation interact with elongation-promoting far-red light. Far-red irradiation alone promotes filament elongation to a greater extent than blue light, but a blue-light irradiation, either following or preceding far-red treatment, strongly inhibits the far-red promotion. In darkness, a slow recovery from the blue-light-induced loss of sensitivity to far-red takes place. The recovery may be greatly accelerated by interposing a red-light treatment between blue and far-red irradiation.     

EFFECTS OF RED AND FAR-RED ILLUMINATION ON THE ELONGATION OF FERN PROTONEMATA AND RHIZOIDS

The elongation of fern protonemata is controlled by red andfar-red light in an atypical fashion. Red light promotes theelongation of young plants but inhibits the elongation of olderplants. Far-red light promotes elongation regardless of filamentage, and the maximum promotion by far-red is greater than thepromotion which red light causes in young filaments. The elongationof rhizoids is under typical red, far-red control. Red lightpromotes elongation, and a period of far-red illumination followingred light treatment negates the promotive effects of red light. ¹ Present address of the authors: Dept. of Bacteriology andBotany, Syracuse University, Syracuse, New York, U. S. A. (Received November 5, 1962; )     

CHANGES IN THE SKIN FLORA OF COD AFTER WASHING AND ICING

SUMMARY: Bacterial counts done on the skin of North Sea cod show that while washing with running sea water greatly reduced the numbers on newly caught fish, contact with ice from a trawler's ice bunker resulted in an immediate large increase on the washed fish.
Washing did not materially alter the percentage representation of the various genera present, but icing with trawler bunker ice could cause major alterations and often added types of bacteria similar to those present on newly caught fish, indicating contamination of the ice on board the trawler.     

CONCENTRATIONS OF ENERGY METABOLITES AND CYCLIC NUCLEOTIDES DURING AND AFTER BILATERAL ISCHEMIA IN THE GERBIL CEREBRAL CORTEX

Abstract— The concentrations of metabolites which reflect energy production or use ( P -creatine, ATP. ADP. 5'AMP, glucose, glycogen and lactate) and cyclic nucleotides (cyclic AMP and cyclic GMP) were measured in gerbil cortex during ischemia and recirculation. Bilateral ischemia of the gerbil brain was chosen as a model to ensure the assessment of short periods of ischemia without ambiguity. The metabolites and cyclic nucleotides were measured after, 1, 5. 20. 30 and 60 min of ischemia; and 1, 5, 30, 60 and 360 min after circulation was reestablished. The greatest changes in metabolites and cyclic nucleotides due to ischemia occurred during the 1st min; ischemia of longer duration had little further effect. However, the restoration of the metabolic profile was altered by the duration of the ischemic period. In general, the longer the period of ischemia, the slower the replenishment of high-energy phosphate compounds and energy sources. Cyclic AMP increased 5- to 13-fold during ischemia; cyclic GMP decreased to as little as one-fifth control values 60min after occlusion. During recirculation, cyclic AMP increased as much as 100-fold, while cyclic GMP increased up to 6-fold. The temporal derangements in cyclic nucleotide concentrations coincide with the loss and restoration of cortical activity; a possible mechanism has been suggested.     

乳茹属真菌的化学成分和活性研究概况

本文从化学结构类型、提取分离方法、结构鉴定和生物活性等方面综述了乳菇属真菌的研究概况。     

RED LIGHT, BLUE LIGHT, AND COPPER ION IN THE PHOTOPERIODIC CONTROL OF FLOWERING IN LEMNA PERPUSILLA 6746

L. perpusilla, 6746 grown in HUTNER's medium (containing a highlevel of EDTA) responds as a short-day plant under white orred light, but is almost completely daylength-indifferent underblue. In a medium containing ca. 2µmoles/liter of unchelatedcopper ion, it flowers rapidly under all photoperiods, white,blue or red. Although certain long-day blue schedules permitflowering even on HUTNER's medium, blue is not simply "inactive"photoperiodically, since inclusion of a single brief red exposurein certain blue schedules is sufficient to prevent floweringas though the whole schedules were red. The indicated blue-redinteraction should prove important for further analyses of photoperiodismin this plant. ¹Research carried out at Brookhaven National Laboratory underthe auspices of the U.S. Atomic Energy Commission.     

CHANGES IN THICKNESS OF THE RED BLOOD CORPUSCLE MEMBRANE

Measurements of the static capacity per cm.² of membrane for the red corpuscle as changed when the cells are made spherical by the addition of lecithin or rose bengal, show a slight increase of capacity, indicating a thinning of the membrane, although the change is not large enough to make it certain that it is real. Furthermore, the membrane capacity shows a slight decrease when spherical cells are swollen in hypotonic saline, indicating a thickening of the membrane, although the change is hardly outside the experimental error. The fact that there is no increase in capacity lends support to the theory that as the cell swells the membrane does not stretch but new material comes from the interior of the cell to make a new portion of the membrane.     

GROWTH PATTERNS OF PEA SEEDLINGS IN DARKNESS AND IN RED AND WHITE LIGHT

Thomson , Betty F., and Pauline Monz Miller . (Connecticut Coll., New London.) Growth patterns of pea seedlings in darkness and in red and white light. Amer. Jour. Bot. 48(3): 256–261. Illus. 1961.—Seedlings of peas were grown in vermiculite at 22°C. and exposed 16 hr. daily to red or white light or kept in darkness. Others were grown in soil in the greenhouse. Samples harvested daily to 16 days were dissected, the length of each internode and leaf measured and the total number of leaves and leaf primordia counted. The form of the stem apex and youngest primordia and interrodes is the same in light as in darkness. Leaf production is accelerated very slightly and the growth of leaves and internodes is decidedly accelerated by light. Leaf-leaf, leaf-internode and internode-internode correlations indicate that the morphogenetic effect of light is limited to later stages of organ growth. Dry weight is consumed more rapidly in light than in darkness, probably because of more rapid growth and slightly greater amounts of respiring tissue in light-grown plants.     

PHOTOSYNTHESIS OF THE RED ALGA GASTROCLONIUM COULTERI (RHODOPHYTA) IN RESPONSE TO CHANGES IN TEMPERATURE,LIGHT INTENSITY,AND DESICCATION1

Previously reported transplantation experiments in the field showed that Gastroclonium coulteri (Harvey) Kylin could survive above its normal intertidal range (0.0–0.5 m above MLLW), except during periods of daytime low tides in spring. Net photosynthetic rate measurements in the laboratory were performed to determine which physical factors might determine the upper boundary for this species in the intertidal zone. Maximum net photosynthesis occurred between 15 and 20° C, but remained positive between 4 and 35° C. The air temperature extremes observed in the field were 2° C (only seen once) and 26° C. Net photosynthesis increased as expected with light intensity to the highest value obtainable in the laboratory, 1400 μEin m^?2 s^?1. Plants collected from the field under higher light intensity (up to 2000 μEin m^?2 s^?2) also showed high rates of photosynthesis. Neither the temperature nor light levels observed in the field were directly damaging to photosynthesis. Desiccation, however, resulted in a sharp decrease in both photosynthesis and respiration. G. coulteri fully recovered from successive daily treatments of about 35% desiccation, but not from successive treatments of 50% desiccation. One exposure to 70% desiccation allowed no recovery of photosynthetic capacity.     

THE LOCALIZATION OF MITOCHONDRIAL NADP-DEPENDENT ISOCITRATE DEHYDROGENASE IN NORMAL AND HYPOXIC CONDITIONS

NADP-dependent isocitrate dehydrogenase is localized in both external and internal membranes and in the mitochondrial matrix from brains of adult and newborn animals. Electrophoretic studies indicate that the mitochondrial enzyme occurs in the form of two isoenzymes; the isoenzyme of the external membranes behaves similarly to that of the cytoplasm. Ischaemia in adult animals results in a decrease in enzyme specific activity, particularly in external membranes, while in the mitochondrial fraction of the newborn the activity of the enzyme increased.     

花生种子劣变过程中一些酶活性的变化

应用20%聚乙二醇处理花生种子8小时,种子活力提高。表现在过氧化氢酶活性较高,过氧化物含量较低,外渗液电导率下降。萌发3天幼苗的超氧物歧化酶和过氧化氢酶活性均高于对照。萌发3天种子的活力指数和21天幼苗生长量均有明显提高。由萌发3天种子子叶分离出线粒体,在悬浮液中的酸性磷酸酯酶活性和 DNA 酶活性均明显降低。     

DEVELOPMENTAL CHANGES IN LEVELS AND FORMS OF CHOLINESTERASES IN MUSCLES OF NORMAL AND DYSTROPHIC CHICKENS

Abstract— Acetylcholinesterase (AChE) and pseudocholinesterase (°ChE) were studied in vivo and during the first several months of development of pectoral and posterior latissimi dorsi (PLD) muscles in normal and dystrophic chickens. Muscle extracts were prepared in a high ionic strength-nonionic detergent medium in the presence of protease inhibitors, in order to obtain complete solubilization and to prevent degradation of intrinsic molecular forms of both enzymes. In both normal and dystrophic pectoral muscles levels of AChE and °ChE increase rapidly in vivo, °ChE accounting for 5–10% of total cholinesterase activity. In the normal pectoral muscle the concentration of both enzymes drops rapidly after hatching with increasing muscle mass; total AChE per muscle remains relatively constant for 30 days post-hatch. In the dystrophic pectoral muscle both AChE and °ChE accumulate after hatching, resulting in greatly elevated levels (approx 10–25-fold) of both enzymes throughout the period studied. Multiple molecular forms of AChE and °ChE are observed in the pectoral muscle by sucrose gradient centrifugation. Four principal forms are distinguished: two light (L₁, L₂), one medium (M), and one heavy (H₂). The °ChE forms are 0.5–1.0 S units lighter than the corresponding AChE forms. L₂ is the predominant light form of AChE, whereas L₁ is the major light °ChE form detected. The lighter forms of AChE predominate in normal and dystrophic embryonic pectoral muscle at day 14, being replaced by the H₂ form by day 19. H₂ is the major °ChE form detected at day 19. After hatching, H₂ AChE is the predominant form found in both of the normal muscles studied. In the dystrophic pectoral muscle, progressive accumulation of the L₂ form of AChE is detected as early as day 4 post-hatch; this form eventually becomes predominant, although the heavier forms are also elevated. In PLD muscle the same phenomenon occurs, but with a slower time course. In dystrophic pectoral muscle a similar rise in the L₁ form of °ChE is first observed by day 4, with heavier forms also elevated in the mature muscle. Thus the alteration in the control of these two enzymes in dystrophic fast-twitch muscles results in an accumulation of the light forms of AChE and °ChE.     

CHANGES IN THE LEVELS OF DNA, RNA, PROTEIN AND DNases IN DEVELOPING AND OLD CHICK BRAIN

—The levels of DNA, RNA, protein and activities of acid and alkaline DNases in developing and old chicken brain were studied. A rapid increase in DNA content was found in the embryonic brain until just prior to hatching. Thereafter, with a transient plateau around the day of hatching, the DNA continued to increase but at a very slow rate. Two-year-old brain was found to have a markedly higher level of DNA as compared to the 10th day postnatal value. RNA showed a steady increase up to the 20th day of embryonic life. Protein levels showed a gradual increase throughout the period studied. Both acid and alkaline DNases exhibited maximum activity during embryonic life, i.e. at a time when rapid cellular proliferation was occurring. With advancing age, the acid DNase activity showed a marked decline thus exhibiting no correlation to the high level of DNA found in the old brain. The alkaline DNase activity, however, was still at a significant level in the 2-year-old brain.     

PHYSIOLOGICAL AND PHOTOSYNTHETIC CHANGES DURING THE FORMATION OF RED APLANOSPORES IN THE CHILOROPHYTE HAEMATOCOCCUS PLUVIALIS1

Changes in physiological and photosynthetic parameters were followed in the freshwater chorophyte Haematococcus pluvialis Flotow (Volvocales) during the transformation of green vegetative cells to red aplanospores.Formation of aplanospores was induced by exposure to a nitrogen-deficient medium. In spite of an increase in cellular volume (from 6.6 to 41 pL) and amassive accumulation of astaxanthin, chlorophyll content of the mature aplanospore decreased only slightly (from 16 to 14.8 pg'cell^?1)as compared to the vegetative cell. Aplanospore formation was characterized by a gradual reduction in the maximal photosynthetic rate and increases in the photosynthetic quantum requirement and minimal turnover time for photosynthetic O₂ evolution.Respiration rate increased (4.2 times)and excretion rate decreased (up to 8.8 times) during aplanospore formation. Measurements of photosynthetic unit “size” and estimation of the cellular content of photosystem II reaction centers suggest that the photosynthetic complex remains relatively centers stable during the formation process and in the mature aplanospore.A functional relationship between the describe changes in the physiology of the cells and their photosynthetic parameters is proposed.     

牵牛花受精前后卵细胞质体和线粒体及其细胞质DNA的变化

应用透射电镜研究了圆叶牵牛（Ｐｈａｒｂｉｔｉｓｐｕｒｐｕｒｅａ （Ｌ．） Ｖｏｙｇｈｔ）和大花牵牛（Ｐ． ｌｉｍ ｂａｔａ Ｌｉｎｄｌ．）卵细胞在受精前和受精后质体和线粒体的变化。观察到卵细胞在受精前高度液泡化,在核周及卵细胞周围的薄层细胞质中有质体和线粒体。质体含１～２ 个较大淀粉粒。线粒体多呈环形或杯状。卵细胞受精后,细胞质增多,质体的数量也明显增加。质体基质变得更加浓厚,并且普遍含有嗜锇的球体。合子中线粒体丰富,但缺乏卵细胞中那种环形或杯状线粒体,多呈圆形。细胞质ＤＮＡ检测的结果表明,卵细胞质ＤＮＡ荧光有大小和形状不同的两类,它们在细胞中随机分布。一类较大,呈环状,可能是线粒体中的ＤＮＡ显示的荧光;另一类小的点状荧光,可能大多是质体ＤＮＡ荧光,前者比后者多。卵细胞受精后,细胞质类核发生变化,表现在数量上明显地比受精前少。研究揭示了牵牛花合子中细胞质ＤＮＡ 减少的现象,说明了母系质体ＤＮＡ 在受精后可能被降解,提供了母系质体不传递到后代的可能机制。