Showing papers by "University of California, Santa Cruz published in 1974"

Elephant Seals: Genetic Variation and Near Extinction

Abstract: Blood samples from northern elephant seals (Mirounga angustirostris), representing five breeding colonies in California and Mexico, were surveyed electrophoretically for protein variation reflecting underlying genetic differences. No polymorphisms were found among 21 proteins encoded by 24 loci. This uniform homozygosity may be a consequence of fixation of alleles brought about by the decimation of this species by sealers in the last century.

The location of nitrite reductase and other enzymes related to amino Acid biosynthesis in the plastids of root and leaves.

Abstract: Density gradient separation of plastids from leaf and root tissue was carried out The distribution in the gradients of the activity of the following enzymes was determined: nitrite reductase, glutamine synthetase, acetolactate synthetase, aspartate aminotransferase, catalase, cytochrome oxidase, and triosephosphate isomerase The distribution of chlorophyll was followed in gradients from leaf tissue The presence of plastids that have retained their stroma enzymes was denoted by a peak of triosephosphate isomerase activity Coincidental with this peak were bands of nitrite reductase, acetolactate synthetase, glutamine synthetase, and aspartate aminotransferase activity The results suggest that most, if not all, the nitrite reductase and acetolactate synthetase activity of the cell is in the plastids The plastids were found to contain only part of the total glutamine synthetase, aspartate aminotransferase, and triosephosphate dehydrogenase activity in the cell Some evidence was obtained for low levels of glutamate dehydrogenase activity in chloroplasts

The Metabolism of Oat Leaves during Senescence: I. Respiration, Carbohydrate Metabolism, and the Action of Cytokinins

Abstract: When the detached first leaves of green or etiolated oat (Avena sativa cv. Victory) seedlings senesce in the dark, their oxygen consumption shows a large increase, beginning after 24 hours and reaching a peak of up to 2.5 times the initial rate by the 3rd day. This effect takes place while the chlorophyll of green leaves, or the carotenoid of etiolated leaves, is steadily decreasing. Kinetin, at a concentration which inhibits the decrease in pigment, completely prevents the respiratory rise; instead, the oxygen consumption drifts downwards. Lower kinetin concentrations have a proportional effect, 50% reduction of respiration being given by about 0.1 mg/l. About one-fifth of the respiratory rise may be attributed to the free amino acids which are liberated during senescence; several amino acids are shown to cause increases of almost 50% in the oxygen consumption when supplied at the concentrations of total amino acid present during senescence. A smaller part of the rise may also be due to soluble sugars liberated during senescence, largely coming from the hydrolysis of a presumptive fructosan. The remainder, and the largest part, of the increase is ascribed to a natural uncoupling of respiration from phosphorylation. This is deduced from the fact that dinitrophenol causes a similar large rise in the oxygen consumption of the fresh leaves or of leaf segments kept green with kinetin, but causes only a very small rise when the oxygen consumption is near its peak in senescent controls. The respiration of these leaves is resistant to cyanide, and 10 mm KCN even increases it by some 30%; in contrast, etiolated leaves of the same age, which undergo a similar rise in oxygen consumption over the same time period, show normal sensitivity to cyanide. The respiratory quotient during senescence goes down as low as 0.7, both with and without kinetin, though it is somewhat increased by supplying sugars or amino acids; glucose or alanine at 0.3 m bring it up to 1.0 and 0.87, respectively.N(6)-Benzylaminopurine and Delta-2-isopentenylaminopurine act similarly to kinetin in repressing the respiratory rise, the former being five times as active as kinetin, while the latter has only 1% of the activity of kinetin. Zeatin also powerfully prevents senescence. Because the repression of the respiratory rise is shown by each cytokinin at the concentration at which it inhibits senescence, the action is ascribed in both cases to the maintenance of a tight coupling between respiration and phosphorylation. It is pointed out that such an effect would explain many features of cytokinin action.A change in the methodology of the senescence experiments is described and compared with the method previously used, and the influence of temperature and age of the plants on the course of leaf senescence are presented in detail.

Lipase Activities in Castor Bean Endosperm during Germination.

Abstract: Two lipases were found in extracts from castor bean (Ricinus communis L.) endosperm. One, with optimal activity at pH 5.0 (acid lipase), was present in dry seeds and displayed high activity during the first 2 days of germination. The second, with an alkaline pH optimum (alkaline lipase), was particularly active during days 3 to 5. When total homogenates of endosperm were fractionated into fat layer, supernatant, and particulate fractions, the acid lipase was recovered in the fat layer, and the alkaline lipase was located primarily in the particulate fraction. Sucrose density gradient centrifugation showed that the alkaline lipase was located mainly in glyoxysomes, with some 30% of the activity in the endoplasmic reticulum. When glyoxysomes were broken by osmotic shock and exposed to KCl, which solubilizes most of the enzymes, the alkaline lipase remained particulate and was recovered with the glyoxysomal "ghosts" at equilibrium density 1.21 g/cm(3) on the sucrose gradient. Association of the lipase with the gly-oxysomal membrane was supported by the responses to detergents and to butanol. The alkaline lipase hydrolyzed only monosubstituted glycerols. The roles of the two lipases in lipid utilization during germination of castor bean are discussed.

Isolation of Intact Plastids from a Range of Plant Tissues

Abstract: A technique for the isolation of intact plastids from spinach (Spinacia oleracea) and pea (Pisum sativum) leaves, pea roots and castor bean (Ricinus communis) endosperm is described. This technique involves brief centrifugation of whole homogenates on density gradients. Intact plastids were located in the gradient by assaying for triose phosphate isomerase activity. Contamination of the plastic peak with mitochondria and microbodies was estimated by measurement of cytochrome oxidase and catalase, respectively. For three of the four tissues the level of contamination of the plastids by these organelles was 2% or less. The sedimentation behavior of microbodies from different tissues is discussed.

Ancestor worship in contemporary Japan

Abstract: NORMAN PERRIN, University of Chicago Written by a leading New Testament scholar, this concise, perceptive introduction to the New Testament reflects the insights of the theologian, the historian of religion, the literary critic, and the philosopher of language. It uses the most modern methods of New Testament scholarship and incorporates such recent developments as the discoveries of the Qumran texts and the Nag Hammadi codices. Professor Perrin has carefully structured the book to be read in close conjunction with the New Testament texts themselves; to facilitate the student's immediate contact with the texts, he provides background material in a series of appendices rather than at the beginning of the book. Included in the appendices are descriptions of the Hellenic world, the situation of the Jewish people during New Testament times, the development of the canon of the Bible, sources for the text of the New Testament, and a discussion of English translations of the New Testament. Paperbound. 385 pages

Role of underthrust oceanic crust in the genesis of a Fijian calc-alkaline suite

Abstract: A test of the proposition that calc-alkaline magmas are direct partial melts of underthrust oceanic crust is presented. It involves numerical evaluations of whether or not the major and trace element and isotopic composition of a Fijian calc-alkaline rock suite is consistent with these rocks representing unfractionated partial melts of oceanic crust at high pressures. Experimental data for one of the samples constrain the calculations. When compositions of liquidus minerals at 27 kb are combined with compositions of the volcanic rocks, close approximations can be made to the composition of oceanic crust only if the degree of partial melting is between ∼20% (dacite) and ∼45% (basaltic-andesite), and if accessory minerals are refractory phases. Concentrations of elements such as K, Rb, Sr, Pb, Th, and U, and 87Sr/86Sr ratios in the Fijian suite can be satisfactorily explained only if the parental material consisted of altered rather than fresh ocean floor basalt. Sediments are not likely to have been involved. Concentrations of Na, Ni, Co, Cr, Sc, V, the REE, Y, Zr, Hf, and Nb cannot be explained unless, or in some cases even if, several accessory phases are partially refractory. Therefore, partial melting of underthrust lithosphere does not seem likely to produce magmas with the composition of at least one quite typical calc-alkaline suite.

The behavioral hierarchy of the molluskPleurobranchaea

Abstract: Feeding behavior and the effect of its occurrence on other, unrelated behaviors were studied in the carnivorous marine gastropodPleurobranchaea calif arnica. The threshold of the feeding response is low and stable: it does not change in a circadian fashion (Fig. 1); it does not change during different behavioral states such as mating (Table 4) and quiescence (“sleep” Table 5); the threshold does not change following aversive electric shock to the oral veil (Table 1); and it does not change with repeated application of food stimuli (Fig. 2). In the present paper only two physiological variables were found to elevate the feeding response threshold; excessive mechanical stimulation (Figs. 3, 4) and satiation with food (Fig. 5).

The Relationship of Acculturation to Cognitive Style among Mexican Americans

Abstract: Tests of cognitive style were administered to Mexican-American children and their mothers in three communities in southern California. Questionnaires on socialization practices and Mexican-American family values were also administered to the mothers. Subjects from the "traditional" community-in which members were most identified with the sociocultural system of Mexican culture-scored in a field-dependent direction. Subjects from the "atraditional" community, whose members are most influenced by mainstream American middle-class values, were most field-independent in cognitive style. Children and mothers of the community influenced by both cultures-the "dualistic" community-obtained scores between those of the other two groups. Mothers from the traditional community were most frequently in agreement with items reflecting indicators of the field-dependent "socialization" cluster, and also with items reflecting the sociocultural system of Mexican-American culture.

Normal forms for real linear Hamiltonian systems with purely imaginary eigenvalues

Abstract: This note gives a concise algorithm for computing a normal form for a real linear Hamiltonian differential equatin which has purely imaginary eigenvalues. This algorithm is then applied to the differential equation which comes from the quadratic terms of the Hamiltonian of the restricted three body problem at a Lagrange equilateral triangle equilibrium point.

The Metabolism of Oat Leaves during Senescence: II. Senescence in Leaves Attached to the Plant.

Abstract: The course of senescence in the first leaves of light-grown Avena seedlings when attached to the plant has been compared with that previously studied in detached leaves and leaf segments. Proteolysis in the leaf, whether attached or detached, is accompanied by markedly polar basipetal transport of amino acids. This polar transport can be superimposed on the known transport of amino acids towards a locally applied cytokinin. In the intact plant, it results in a strong movement into the roots. The reducing sugars, which are set free in senescence, do not participate appreciably in this polar transport phenomenon. If cytokinin is applied directly to the roots, then, if the plants are 7 days old, it becomes transported upward into the basal parts of the leaf and there delays the senescence process. However, if the plants are 10 days old, a “reverse Mothes effect” occurs, in which senescence of the leaf is actually promoted and part of the amino acids transported into the roots is synthesized into root protein.

Nuclear DNA amounts in crustacea

Abstract: 1. 1. Nuclear DNA amounts of thirty-eight species of crustaceans, belonging to three subclasses and seven orders, were determined by cytophotometry or by fluorometric assay. 2. 2. DNA contents vary over a wide range (0·7–22·6 pg haploid). A modal value of about 2·5 pg is typical for many groups. 3. 3. The extreme values are found in groups with peculiar morphological adaptations, and the correlation between specialized morphology and low amounts of DNA in barnacles parallels a comparable trend in other invertebrate groups and in vertebrates.

Localization of enzymes of glycolate metabolism in the alga Chlorogonium elongatum.

Abstract: Organelles in homogenates from autotrophic cells of Chlorogonium elongatum were separated on linear sucrose gradients. The distribution of enzymes typical of leaf peroxisomes was determined.Whereas more than 60% of the catalase activity was particulate and recovered in microbodies at a mean density of 1.225 g/cm(3) within the gradient, in most experiments only 5 to 10% (as a maximum 30%) of the NAD-dependent hydroxypyruvate reductase was particulate, and this was recovered principally at density 1.19 g/cm(3). This distribution coincides with that of cytochrome oxidase, malate dehydrogenase, and isocitrate dehydrogenase, the mitochondrial markers. Glyoxylate-glutamate aminotransferase and glycolate dehydrogenase showed a similar distribution pattern to that of NAD-dependent hydroxypyruvate reductase. Thus in Chlorogonium the enzymes of the glycolate pathway are not associated with the microbodies that are recovered at density 1.225 g/cm(3).The single large chloroplasts of the Chlorogonium cells are broken during grinding, and this probably accounts for the finding that NADP-glyoxylate reductase was recovered only in the soluble fractions of the gradient.

Elephant seals on the Farallones: population structure of an incipient breeding colony.

Abstract: The colonization of Southeast Farallon Island, California, by northern elephant seals, Mirounga angustirostris , began in 1959 with the appearance of a single animal. By 1971, over 100 juveniles were counted during the fall and spring haulout. Breeding began on the island in 1972. The age of juveniles and their pattern of island use for the two years preceding the birth was similar to that of Ano Nuevo Island, a nearby rookery. The majority of seals onshore during the fall and spring peaks were juveniles less than two years old. Tagged individuals sighted on Southeast Farallon Island were born on rookeries to the south: Ano Nuevo Island, San Miguel Island, and San Nicolas Island. Males were observed more frequently than females. Utilization of the hauling-out place by juveniles was not determined primarily by availability of space. During the first breeding season, adult females arrived on the island before the first male was observed.

Cellular DNA content of the echinodermata.

Abstract: 1. 1. The cellular DNA content is reported for thirty-nine species of echinoderms. 2. 2. Asteroids and Echinoids both average low amounts of DNA while Ophiuroids and Holothuroids have two to three times as much. 3. 3. DNA content decreases with specialization in the holothuroids.

Calculations of the Early Evolution of Jupiter

Abstract: The evolution of the protoplanet Jupiter is followed, using a hydrodynamic computer code with radiative energy transport. Jupiter is assumed to have formed as a subcondensation in the primitive solar nebula at a density just high enough for gravitational collapse to occur. The initial state has a density of 0.0015 nanograms per cu cm and a temperature of 43 K; the calculations are carried to an equilibrium state where the central density reaches 0.5 g per cu cm and the central temperature reaches 25,000 K. During the early part of the evolution the object contracts in quasi-hydrostatic equilibrium; later on hydrodynamic collapse occurs, induced by the dissociation of hydrogen molecules. After dissociation is complete, the planet regains hydrostatic equilibrium with a radius of a few times the present value. Further evolution beyond this point is not treated here; however the results are consistent with the existence of a high-luminosity phase shortly after the planet settles into its final quasi-static contraction.-

Abdominal movements during backward walking in crayfish

Abstract: 1. A study was made of the neuronal connectivity which produces cyclical abdominal flexion and extension in crayfish during backwards terrestrial walking. 2. On the basis of known coupling, intracellular recording and stimulation, and antidromic stimulation, it is concluded that motor neuron properties alone cannot be responsible for the observed output pattern. 3. The properties of a network of intersegmental interneurons isolated in area 85 of the connective are analyzed, and it is concluded that this network is responsible for driving the motor neurons to produce the cyclical pattern described. 4. A model based upon demonstrated connections among the driving neurons and between these neurons and the motor neurons is proposed which accounts for the observed behavior.

Isolation and Characterization of Organelles from Soybean Suspension Cultures

Abstract: Whole homogenates from cells of Glycine max grown in suspension culture were centrifuged on linear sucrose gradients. Assays for marker enzymes showed that distinct peaks enriched in particular organelles were separated as follows: endoplasmic reticulum (density 1.10 g/cm3, NADH-cytochrome-c reductase), Golgi membranes (density 1.12 g/cm3, inosine diphosphatase), mitochondria (density 1.18—1.19 g/cm3, fumarase, cytochrome oxidase) and microbodies (density 1.21—1.23 g/cm3, catalase). In cells which had ceased to grow (stationary phase) only a single symmetrical catalase peak at density 1.23 g/cm3 was observed on the sucrose gradient. During the phase of cell division and expansion a minor particulate catalase component of lighter density was present; its possible significance is discussed.

The senescence of isolated chloroplasts

Abstract: Because previous work indicated that senescence of oat leaves in darkness probably centers in the cytoplasm, the senescence of chloroplasts isolated from the same material and carefully purified was studied. The rate of loss of chlorophyll was about one-tenth of that which takes place in the isolated leaves at the same temperature, while the loss of protein, though slightly more rapid, was still only 36% of the rate observed in the leaf after 7 days. This unexpected stability of the chloroplasts is matched by their photosynthesis, 81% of photosystem I and 35% of photosystem II being present after 3 days at 25°. Traces of system I, but not of system II, were still detectable even after 7 days.

Conceptual developments in metabolic control, 1924-1974.

Abstract: A brief sketch is given of the development of the understanding of the respiratory mechanism in plants over the past 50 years. Against this background the following aspects of control are discussed: (a) nonreversibility of catabolic sequences; (b) compartmentation of reactions and reactants; (c) control by amount of enzyme; (d) control by NAD and NADP; (e) control by ADP supply; (f) pacemaker reactions in glycolysis; and (g) control at branch points: further examples of allostery.

The Effect of Hadacidin on Bud Development and its Implications for Apical Dominance

Abstract: Hadacidin, which is known to inhibit the enzyme adenylo-succinate synthetase, was applied locally to lateral buds on decapitated Pisum sativum L. plants. In controls the buds grew out normally, but the treated buds were almost completely inhibited. After a delay, the buds overcame the inhibition, and their subsequent outgrowth could be further hastened by the local application of a cytokinin. The inhibition, unlike that due to IAA, was not transported to a second bud, and it could be largely reversed by kinetin or dimethylallylaminopurine. Adenine itself produces little or no reversal, however. There was some reversal by aspartic acid, which is known to reverse, at least partially, the hadacidin inhibition of the isolated enzyme. It is deduced that lateral bud development is dependent on the synthesis of a cytokinin, which may take place by a biochemical route similar, but probably not identical, to that for adenine. It follows that this synthesis takes place locally in the bud itself.