The production of ethylene by plants determined by means of paper chromatography

Ethylene was collected in methanol solution of mercuric acetate and the addition compound formed was then separated by means of paper chromatography. The spot area and colour intensity after detection were determined using a densitometer. The amount of collected ethylene was calculated from a calibration curve. The ethylene liberated from plant samples was collected during one or two days. During this period the amputation of the whole plant organs did not influence ethylene production. Changes in ethylene production were found after segmentation of the tissue or after the treatment with auxin and Co²⁺ ions. The above-ground parts of investigated herbs released 0.3 to 3.5 μl of ethylene per kg fresh weight per hour. The leaves of investigated trees released 1 to 20 μl of ethylene per kg f.w. per hour. The rate of the production of ethylene seems to be specific for a given species.     

Factors determining the biosynthesis of griseofulvin and similar substances

Была высказана гипотеза, что биосинтез гризеофульвине, цитромицетина, фульвиновой кислоты, фусаeубине, руброфусарина и родствеооых им вешеств протекаеР не путем конденсации линейнон цепочки, а из двух более коротких цепочек, которые возникают конденсацией 4 и 3 ацетатных единп. реакции, осушествляющиеся на уровне этих цапочек (илн прнмежувочных структур) метиляция, редукция, и, возможно, последующая дегидратация или только эноэизация— определяют направление дальнeйшeй кондeнсации в такой стeпeни, что конeчныe продуктыотдичаются своeй структурой.     

Cost of allogeneic and autologous blood transfusion in Canada. Canadian Cost of Transfusion Study Group.

OBJECTIVE: To determine the cost, from a societal perspective, of blood transfusion in Canada. STUDY DESIGN: Cost-structure analysis. SETTING: Data were collected from eight hospitals and from six blood centres operated by the Canadian Red Cross Society in four provinces. OUTCOME MEASURES: Costs associated with four stages of transfusion-- collection, production, distribution and delivery--in 1933 were assessed. Costs were divided into the following categories; personnel, purchases, external services, overhead, donors'' time, patients'' time (for autologous transfusion), wastage and infection. RESULTS: The mean overall cost of a transfusion performed on an inpatient basis was $210 per unit of red blood cells for an allogeneic transfusion and $338 per unit of blood for an autologous transfusion. The mean cost of an allogeneic transfusion performed on an outpatient basis was $280 per unit of red blood cells. CONCLUSION: The costs determined in this study can be used in future studies comparing the cost-effectiveness of allogeneic transfusion with that of alternative methods.     

Organ correlations inchenopodium rabrum l. shoots studied by Means of32P Distribution

21-day old plants ofChenopodium rubrum L. ecotype 374 were used. Organ relationships in the shoots were investigated by³²P distribution, which indicated different organ correlations in plants grown in continuous light and in plants treated with flower-inducing and non-inducing dark periods. Dark periods were associated with a low³²P distribution in young leaves and a high one in axillary buds. In the following light period the high³²P distribution in axillary buds continued whereas the³²P distribution in the leaves on the main axis increased and was similar to that in plants grown in continuous light. The high³²P distribution in axillary buds was brought about by both, flower-inducing and non-inducing dark treatments. Decapitation resulted in a high³²P distribution in buds, in continuous light an increased³²P distribution was also found in leaves. These effects were not fully cancelled by IAA application. The results are discussed with respect to an assumption that decrease of apical dominance represents a step in a sequence of events leading to flowering.     

Some Properties of Neutral Proteolytic System in Rabbit Skeletal Muscle

The properties of the neutral proteolytic activity concentrated in a fraction (F–1) separated from rabbit muscle homogenate were examined by measuring the effects of various reagents and metal ions, the time course of the proteolysis and Ca-stability. The obtained results have indicated that F–1 contains two types of neutral protease active on proteins, tentatively named Protease I and II, The former, which is activated by Ca²⁺ and Ca-labile, shows an explosive production of Cu-Folin phenol reagent positive materials at the early stage of incubation. The latter, which is Ca-stable, shows a large production of ninhydrin positive materials throughout the incubation time. The proteolysis by F–1 was similar to the autolysis of muscle homogenate in all the properties examined. Therefore, Proteases I and II were assumed to be main enzymes responsible for the muscle proteolysis at the neutral pH region. As there has been no factor denying their functioning in living muscle, it is probable that Proteases I and II take important parts in the muscle catabolism.     

Requirement of Retinoic Acid Receptor β for Genipin Derivative-Induced Optic Nerve Regeneration in Adult Rat Retina

Like other CNS neurons, mature retinal ganglion cells (RGCs) are unable to regenerate their axons after nerve injury due to a diminished intrinsic regenerative capacity. One of the reasons why they lose the capacity for axon regeneration seems to be associated with a dramatic shift in RGCs’ program of gene expression by epigenetic modulation. We recently reported that (1R)-isoPropyloxygenipin (IPRG001), a genipin derivative, has both neuroprotective and neurite outgrowth activities in murine RGC-5 retinal precursor cells. These effects were both mediated by nitric oxide (NO)/S-nitrosylation signaling. Neuritogenic activity was mediated by S-nitrosylation of histone deacetylase-2 (HDAC2), which subsequently induced retinoic acid receptor β (RARβ) expression via chromatin remodeling in vitro. RARβ plays important roles of neural growth and differentiation in development. However, the role of RARβ expression during adult rat optic nerve regeneration is not clear. In the present study, we extended this hypothesis to examine optic nerve regeneration by IPRG001 in adult rat RGCs in vivo. We found a correlation between RARβ expression and neurite outgrowth with age in the developing rat retina. Moreover, we found that IPRG001 significantly induced RARβ expression in adult rat RGCs through the S-nitrosylation of HDAC2 processing mechanism. Concomitant with RARβ expression, adult rat RGCs displayed a regenerative capacity for optic axons in vivo by IPRG001 treatment. These neuritogenic effects of IPRG001 were specifically suppressed by siRNA for RARβ. Thus, the dual neuroprotective and neuritogenic actions of genipin via S-nitrosylation might offer a powerful therapeutic tool for the treatment of RGC degenerative disorders.     

Early Archean planktonic mode of life: Implications from fluid dynamics of lenticular microfossils

Lenticular, and commonly flanged, microfossils in 3.0–3.4 Ga sedimentary deposits in Western Australia and South Africa are unusually large (20–80 μm across), robust, and widespread in space and time. To gain insight into the ecology of these organisms, we performed simulations of fluid dynamics of virtual cells mimicking lenticular forms of variable sizes, oblateness, flange presence, and flange thickness. Results demonstrate that (a) the flange reduces sedimentation velocity, (b) this flange function works more effectively in larger cells, and (c) modest oblateness lowers sedimentation rate. These observations support interpretations that the lenticular microbes were planktonic—a lifestyle that could have been advantageous in an early Earth harsh environment including violent volcanic activities, repeated asteroid impacts, and relatively high UV‐radiation. Although the robustness of these organisms could have provided additional protection on the early Earth, this architecture may have impeded a planktonic lifestyle by increasing cell density. However, our data suggest that this disadvantage could have been compensated by enlargement of cell volume, which could have enhanced the ability of the flange to slow sedimentation rate, especially if coupled with vacuolation. The results of this simulation study may help to explain the unique morphology and unusually large size of these Archean microfossils.     

Suppression of Recombination Losses in Polymer:Nonfullerene Acceptor Organic Solar Cells due to Aggregation Dependence of Acceptor Electron Affinity

Here, it is investigated whether an energetic cascade between mixed and pure regions assists in suppressing recombination losses in non‐fullerene acceptor (NFA)‐based organic solar cells. The impact of polymer‐NFA blend composition upon morphology, energetics, charge carrier recombination kinetics, and photocurrent properties are studied. By changing film composition, morphological structures are varied from consisting of highly intermixed polymer‐NFA phases to consisting of both intermixed and pure phase. Cyclic voltammetry is employed to investigate the impact of blend morphology upon NFA lowest unoccupied molecular orbital (LUMO) level energetics. Transient absorption spectroscopy reveals the importance of an energetic cascade between mixed and pure phases in the electron–hole dynamics in order to well separate spatially localized electron–hole pairs. Raman spectroscopy is used to investigate the origin of energetic shift of NFA LUMO levels. It appears that the increase in NFA electron affinity in pure phases relative to mixed phases is correlated with a transition from a relatively planar backbone structure of NFA in pure, aggregated phases, to a more twisted structure in molecularly mixed phases. The studies focus on addressing whether aggregation‐dependent acceptor LUMO level energetics are a general design requirement for both fullerene and NFAs, and quantifying the magnitude, origin, and impact of such energetic shifts upon device performance.     

Aggregation of Expanded Huntingtin in the Brains of Patients With Huntington Disease

Huntingtin containing an expanded polyglutamine causes neuronal death and Huntington disease. Although expanded huntingtin is found in virtually every cell type, its toxicity is limited to neurons of certain areas of the brain, such as cortex and caudate/putamen. In affected areas of the brain, expanded huntingtin is not found in its intact monomeric form. It is found instead in the form of N-terminal fragments, oligomers and polymers, all of which accumulate in the cortex. Whereas the oligomer is mostly soluble, the polymers and the fragments associate with each other and with other proteins to form the insoluble inclusions characteristic of the disease. It is likely that the aggregates containing expanded huntingtin are toxic to neurons, but it remains to be determined whether the oligomer or the inclusion is the toxic species.Key Words: huntingtin, polyglutamine, aggregation, oligomer, polymer, N-terminal fragments, transglutaminase     

Circadian variation in total plasma tryptophan. Antidepressant treatment: drugs and phase advance.

The authors investigated hourly total plasma tryptophan concentrations over a 24 hour period in 3 patients with bipolar depression during 2 types of treatment: a phase advance process and conventional antidepressant therapy. Both treatment modalities increased the 24 hour mean tryptophan levels and the amplitude of circadian tryptophan concentrations. By contrast, in a previous study, moderately decreased tryptophan levels and a blunted amplitude in the circadian rhythm were observed in these same patients in a depressive phase.