Stimulation of plant development by some uracil analogues

Zusammenfassung Es wurde eine entwicklungsfördernde Wirkung von 5-Bromuracil und 5-Nitrouracil bereits in geringen Mengen auf manche Pflanzen (unter anderem Tomaten, Gurken und Gartenlattich) festgestellt. 5-Bromuracil wird dabei nicht in die Pflanzennukleinsäuren eingebaut, sondern unterliegt einem schnellen Abbau; weiterhin verursacht der Stoff eine Hemmung des Uracilabbaues. Die Möglichkeit einer Beeinflussung der genetischen Eigenschaften wird diskutiert.     

Antiviral activity of coralloid root ofCycas revoluta extract against some viruses of tomato plant

Summary Crude coralloid root extract ofCycas revoluta showed significant antiviral activity against viruses of the tomato plant (PVX, PVY, TMV, TAV and TRSV) when applied 24 h before virus inoculation, or when mixed with different virus inocula before virus inocultion, in hypersensitive and systemic hosts. No such inhibition was observed when extract was applied 24 h after virus inoculation. TAV did not show any inhibitory response in a systemic host.Authors are thankful to Dr S. N. Gupta and Dr (Smt.) K. Shukla for their valuable guidance and providing laboratory facilities and U.G.C. for financial assistance.     

Further studies on the sensitivity of plant pathogenic microorganisms towards some naturally occurring chalcones and flavanones

Summary The antifungal and antibacterial activities of some quinochalcones, chalcones and flavanones isolated fromDidymocarpus pedicellata have been assayed.The authors are grateful to B.C.K.V.V. and CSIR, India, for financial assistance.     

Skin-photosensitizing activity of some methylpsoralens

Riassunto Alcuni metil-derivati del psoralene hanno una attività fotosensibilizzatrice cutanea notevolmente più forte dello stesso psoralene, considerato finora la più attiva sostanza di questo gruppo. Il derivato, finora trovato con maggiore potere fotosensibilizzante è l'8-metilpsoralene.

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The preparative work of the unknown compounds will be published elsewhere.     

Digestive enzymes of some earthworms

Summary 4 species of tropical earthworms differed with regard to enzyme activity. The maximum activity of protease and of cellulase occurred in the posterior region of the gut of the earthworms. On the averageOctochaetona surensis shows maximum activity andDrawida calebi shows minimum activity for all the enzymes studied.     

The plant nuclear envelope

This review summarizes our present knowledge about the composition and function of the plant nuclear envelope. Compared with animals or yeast, our molecular knowledge of the nuclear envelope in higher plants is in its infancy. However, there are fundamental differences between plants and animals in the structure and function of the nuclear envelope. This review will compare and contrast these differences for nuclear pore complexes, nuclear transport, inner nuclear envelope proteins and the role of the nuclear envelope during mitosis. In some cases, seemingly 'novel' aspects of plant nuclear envelope function may provide new insight into the animal cell nucleus.     

Patterns in plant parthenogenesis

Summary Plant taxa that reproduce asexually display some distinct geographical and ecological patterns. A literature review reveals that such taxa 1) tend to have larger ranges, 2) tend to range into higher latitudes, and 3) tend to range to higher elevations than do their sexual relatives. Asexual taxa have a greater tendency than sexual taxa do to colonize once-glaciated areas. These trends have previously been identified as characteristic of parthenogenetic animals as well. While many authors have interpreted these trends as providing support for the biotic uncertainty hypothesis for the maintenance of sex, these trends are consistent with several other interpretations as well. Furthermore, all of these interpretations have ignored the positive correlation that exists between ploidy level and breeding system: asexual plant and animal taxa are generally polyploid, while their sexual relatives are generally diploid. Evidence is presented for plants, and by extension for animals as well, that high ploidy levels alone could (independent of breeding system) endow individuals with the ability to tolerate these extreme environments. For this reason, it appears premature to interpret observed distribution patterns as evidence to support hypotheses about what forces maintain sexual reproduction. Only experimental tests, using sexuals and asexuals of comparable ploidy levels, can permit us to discriminate among the alternatives.     

The plant thioredoxin system

Thioredoxins are small proteins catalyzing thiol-disulfide interchange and are involved in the regulation of the redox environment of the cell. In plants, the thioredoxin system is particularly complex since at least 20 thioredoxin isoforms are found in the plant model Arabidopsis thaliana. Based upon primary sequence analysis and subcellular localization, thioredoxins can be classified into different groups and subgroups. Different pathways allowing thioredoxin reduction also coexist in the plant involving ferredoxin-thioredoxin reductase, thioredoxin reductases and the glutathione/glutaredoxin system. This review discusses the literature of plant thioredoxins with emphasis on recent findings in the field.Received 7 July 2004; received after revision 11 August 2004; accepted 17 August 2004     

The antimitotic activities of some benzodiazepines

Among 9 benzodiazepines, tested on the proliferation of synchronously dividing flagellate cells, only diazepam and medazepam can induce an accumulation of abnormal mitotic figures after 24 h of treatment. It seems that there is not a direct relation between the activity of benzodiazepines on the central nervous system and their ability to inhibit mitosis.     

Photoregulation of some enzymes fromNeurospora crassa

Summary Light-grown cultures ofNeurospora crassa showed photoregulation of a number of enzymes. Proteases and cytosolic malate dehydrogenase showed an increase in activity. There was a decrease in the activity of mitochondrial malate dehydrogenase, isocitrate dehydrogenase and cytosolic glucose-6P-dehydrogenase, isocitrate dehydrogenase and isocitrate lyase.     

Interaction of glutaraldehyde with some micro-organisms

Résumé La glutaraldéhyde produit une couleur rouge chez quelques genres de bactéries. Cette couleur est prise par la paroi cellulaire des organismes.     

Argyrophilic intranuclear bodies of plant cells

Summary Within interphase nuclei of meristematic cells of plants there are small spherical bodies that stain intensely with silver. Their number is related to the DNA content of the species.     

Histochemistry of some trout respiratory muscles

Summary A histochemical study has been made of the main cranial muscles which produce ventilation movements of the rainbow trout. It is shown that a greater proportion of red(aerobic) fibres is present in those muscles known to be active during shallow ventilation than those which become active at greater ventilation volumes. An ordered recruitment of red, pink and white fibres within these muscles is also likely.This work was carried out when I.A. Johnston was holding an NERC Post-Doctoral Research Fellowship (1973–75).