Genome relationship betweenPsathyrostachys huashanica andP. fragilis (Poaceae)

Hybrids between the Chinese endemic speciesPsathyrostachys huashanica Keng and the SW. Asian speciesP. fragilis (Boiss.)Nevski (all 2n = 14) developed normally but were completely sterile. Meiotic analyses revealed a high chiasma frequency indicating that the two species as well asP. juncea (Fisch.)Nevski share the same basic genome (called N). The hybrid nature of the plants was established through karyotype analysis and Giemsa C-banding.     

An acetyl esterase of Trichoderma reesei and its role in the hydrolysis of acetyl xylans

Summary An acetyl esterase was purified from Trichoderma reesei by cation and anion exchange chromatography. The enzyme had a molecular weight of 45 000 as determined by SDS-electrophoresis, or 67 000 as determined by gel filtration. In chromatofocusing the enzyme was shown to consist of two isoenzymes with isoelectric points of 6.8 and 6.0. The enzyme showed activity towards naphthyl acetate, triacetin and glucose-and xylose acetates. However, it liberated acetic acid from acetylated xylo-oligomers only to a small extent. The liberation of acetic acid from the oligomeric substrate was enhanced by addition of endoxylanase and -xylosidase.     

Expression of genes for plastid membrane proteins in barley under intermittent light conditions

Barley plants grown under intermittent light show a plastid membrane composition intermediate between those of etioplasts and chloroplasts. In particular protochlorophyll reductase disappears from the membranes whereas the 32000 protein, coded for by chloroplast DNA, becomes integrated into the membranes. The light-harvesting chlorophyll a/b protein does not accumulate within the membranes even after 11 d of development, while the corresponding mRNA can already be observed after 4 d and is translated under in vivo conditions.Abbreviations LHCP light-harvesting chlorophyll a/b protein - IL intermittent light - LD light-dark (12-h day) - EGTA ethyleneglycol-bis(oxy-ethylenenitrile)tetraacetic acid     

Kinetics of the appearance of mRNA for light-harvesting chlorophyll a/b protein in polysomes of barley

Polysomes from dark-grown and illuminated barley seedlings were translated in cell-free systems. The translation products reacting with the antibody against the light-harvesting chlorophyll a/b protein (LHCP) were analyzed by polyacrylamide gel electrophoresis. It was found that, in addition to the precursor protein of LHCP, a product was obtained that co-migrated with the mature protein. Furthermore, the results show that the light-induced proly(A)RNA for LHCP is integrated into the polysomal complex without delay, indicating that the integration of LHCP into the membrane is controlled at a higher level of gene expression.     

Towards a marxist demography: A comparison of Puerto Rican landowners, peasants and rural proletarians

Conclusion The basic axis of the analysis presented in this inquiry has been the comparison of three barrios and three social classes. The following generalizations can be made:The landowning class was older and not rapidly replacing itself; the heads were united with their spouses in legal unions within simple family households that were larger than the households of the other social classes. Landowners were primarily whites. When they reached old age, most had mature children living with them to provide support and continuity.The rural proletarians, who were most rapidly reproducing themselves, as an apparent function of lower life-expectancy, typically lived in simple family households united by legal or consensual unions, or headed by widowers. They tended to be mulattos. Fewer proletarian households headed by elderly persons had their own mature male children at home. The peasantry was the class most rapidly reproducing itself, and had the largest average number of children in the household, as well as the largest proportion of households with agregados present. The flexibility of social organization among peasants is indicated by the incidence of consensual unions and of extended family households. Landless peasants tended to live in legal unions and in simple family households, similar to the rural proletarians. Only half of the peasant households headed by older persons had resolved the social security problem through family structures that included mature male children; agregados may have served the function of providing support and continuity.The fourth group discussed here, although not properly speaking a social class, is the significant number of households headed by women-domestics. A few were widows, but most had not married, or perhaps had not maintained consensual unions. These households appear to have existed in a more or less direct proportion to rural proletarian households It is not clear whether they were consensual unions in transition, obscured polygyny, represented a stable adaptation of women heads, or some other, unrecognized adaptation. The characteristics of the households headed by women-domestics indicate that if they stood by themselves without direct links to employment or to subsistence; life for them must have been very difficult.The demographic and agrarian patterns analyzed, clearly establish that the three barrios represent various degrees of articulation to the evolving plantation system, ranging from the peasant-proletarian community of Sabana Eneas, through the proletarian community of Maresúa, to the landowner community of Rosario Alto. Stated in different terms, these barrios reveal the differential effects of proletarianization, which probably affected Maresúa more than the other two barrios, because of its linkage with the plantation system.The significance of this interpretation is that the differing circumstances presented contrasting bases for change and stability in preinvasion Puerto Rico. Rosario Alto's lack of articulation with the plantation system probably meant that its characteristics would persist longer than those of the other two barrios, while the demographic and agrarian structures of Maresúa would change most rapidly. The peasant orientation of Sabana Eneas provided some elasticity in response to the demands of the plantation system.Some summary remarks may be added about the problems cited by Mintz for the materialist historiography of rural populations. While basic characteristics, including the hierarchy of social relationships, are discernible from historical documents, the most important aspect of peasant and rural proletariat society is not. I refer to the dialectical movement of persons between peasant and proletarian adaptations throughout their life cycles. There were instances of peasants with proletarian sons, as well as of landowners with peasant and proletarian sons, but not a sufficient number in either case to establish a generalization. In order to understand this process, the anthropologist must be prepared to dissect the stages of individual and family life cycles, just as the economist deploys marxist economic theory in order to disaggregate the circuits of capital, and thus come to understand the generation of surplus value . This in turn requires a familiarity with, and willingness to use, appropriate quantitative techniques. In future analyses of these Puerto Rican census materials and related sources, I hope to demonstrate the utility of such an approach in a marxist framework.James Wessman teaches in the Department of Sociology, Saint Olaf College, Northfield, Minnesota.

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Comparison of Neurologic Responses to the Use of Medetomidine as a Sole Agent or Preanesthetic in Laboratory Beagles

Different dose regimens of medetomidine (a potent α2-adrenergic agonist), adding up to a combined dose of 80 µg/kg, were administered to laboratory beagles to determine physiologic responses including neurologic. The study was intended to determine EEG responses where sufficient sedative and analgesic effects are reached with medetomidine and in contrast its effects when used with ketamine or halothane. Cardiopulmonary responses were very similar in each dose regimen, showing the characteristic properties of single doses of 80 µg/kg of medetomidine. Effective sedative and analgesic duration seemed to be a function of when the largest dose was administered. Adequate additional sedative and analgesic could be gained from injections at doses of half of the initial one. The potent sedative and analgesic effects of medetomidine confirmed by neurologic evaluation supports its potential use as a premedication to general anesthesia in dogs. In this study, 2 different doses of medetomidine were also tested as premedication to both ketamine HCl and halothane anesthesia. Neorologic responses were determined at the same time cardiopulmonary parameters, anesthetic quality, and dose requirements were recorded. Medetomidine was found to have favorable qualities in conjunction with these anesthetics. Cardiopulmonary parameters remained satisfactory in both groups as preanesthetic medication prior to halothane, but no additional benefits could be seen from doses of 40 µg/kg medetomidine compared to 20 µg/kg, except a significant 30% reduction in halothane requirement. The positive chronotropic and inotropic properties of ketamine restored the medeto-midine-induced bradycardia and produced a short anesthetic period of 15 to 30 min depending on the dose of medetomidine. The quality of anesthesia was better when 40 µg/kg medetomidine was used, but recorvery was quicker with 20 µg/kg medetomidine. Medetomidine significantly reduced cerebral activity as demonstrated by recordings of total amplitude and frequency evaluation of the EEG with compressed spectral analysis. This analytical method was effective in confirming clinical signs of sedation, analgesia, and anesthesia in canine subjects.     

Effect of potassium on uptake and incorporation of ammonium-nitrogen of rice plants

1. Rice was grown for 5 months in a sand solution culture at two different

1. K levels. The higher K supply resulted in a reduced uptake of Na +, Mg ++, and Ca++ by shoots. The uptake of NH4+-N of the shoots, however, was increased by the higher K supply.
2. In short term experiments, ill which the NH4+-N of the uptake solution was labelled by N 15, increasing K concentrations in the uptake solution did not depress the NH4 + uptake of young rice plants. Higher K concentrations in the uptake solution favoured the translocation of labelled N from the roots to the shoots. In some cases the higher K levels resulted also in an enhanced transfer rate of labelled N from the soluble to the insoluble N fraction.
3. Increasing levels of Mg++ in the uptake solution did not affect the uptake of labelled NH4-N.
4. I t is concluded that K + and NH4 + do not compete for common binding sites of the uptake mechanism in rice roots. This lacking competition suggests the speculation that NH4+-N is absorbed mainly in form of NH8 by plant cells.