Formative effects of morphactin on the shoot apical meristem of flax (linum usitatissimum L.).

The effect of a morphactin -- CF1 -- (2-chloro-9-hydroxyfluorene-9-carbocylic acid-methyl ester) on the morphogenesis of shoot apical meristem was studied on L. usitatissimum L. at three levels of supply. CF1 at 10 and 100 parts/10(6) induced repeated gamophylly resembling a concentric cupulate structure. GA3 superimposed at two levels viz. 10 and 100 parts/10(6) did not reverse this effect. The effect of CF1 is dose-dependent and reversal to normal behaviour occurs when the effect of CF1 wears off.     

Comparative effects of organic and inorganic nitrogen sources applied to a flooded soil on rice yield and availability of N

A pot experiment was conducted to study the effect of organic and inorganic nitrogen (N) sources on the yield and N uptake of rice from applied and native soil-N. The residual effect of these N sources on a succeeding wheat crop was also studied. Organic N was applied in the form of ¹⁵N-labelled Sesbania aculeata L., a legume, and inorganic N in the form of ¹⁵N-labelled ammonium sulphate. The two sources were applied to the soil separately or together at the time of transplanting rice. Recovery of N by rice from both the applied sources was quite low but both sources caused significant increases in biomass and N yield of rice. Maximum increase was recorded in soil treated with organic N. The residual value of the two materials as source of N for wheat was not significant; the wheat took up only a small fraction of the N initially applied. Loss of N occurred from both applied N sources, the losses being more from inorganic N. Both applied N sources caused a substantial increase in the availability of soil-N to rice and wheat; most of this increase was due to organic N and was attributed to the so-called ‘priming’ effect or ANI (added nitrogen interaction) of the applied material.     

Changes in the levels of catecholamines, hexokinase and glucose 6-phosphate dehydrogenase in red cell aging

The activity of the enzymes hexokinase and glucose 6-phosphate dehydrogenase and the level of catecholamines were measured in isolated rat Red Blood Cells (RBC) during cellular aging. The results clearly showed a linear decline in the two enzyme profiles with corresponding increase in age of RBC. A decrease of 75-85% in the activities were found in the oldest cell fractions as compared to the youngest. The levels of glycosylated haemoglobin and catecholamines were found to increase with aging. A correlation can probably be established between the enzyme activities, the levels of glycosylated haemoglobulin and catecholamines during aging.     

Changes in erythrocyte glutathione peroxidase and glutathione reductase in alloxan diabetes

Glutathione peroxidase and glutathione reductase activities were measured in erythrocytes from control, diabetic and insulin-treated diabetic rats. A significant decrease in the activity of glutathione peroxidase and an increase in the glutathione reductase activity were found with increase in the time of diabetes which may result in the alteration in the activity of the pentose phosphate pathway by the modulation of the levels of NADPH. Insulin administration reverses the change in the activity of glutathione peroxidase but does not reverse the glutathione reductase activity during diabetes. The overall changes may be due to changes in the levels of insulin, triiodothyronine and thyroxine.     

Identifying Mozambique's most critical areas for plant conservation: An evaluation of protected areas and Important Plant Areas

Successful protected area networks must represent biodiversity across taxonomic groups. However, too often plant species are overlooked in conservation planning, and the resulting protected areas may, as a result, fail to encompass the most important sites for plant diversity. The Mozambique Tropical Important Plant Areas project sought to promote the conservation of Mozambique's flora through the identification of Important Plant Areas (IPAs). Here, we use the Weighted Endemism including Global Endangerment (WEGE) index to identify the richest areas for rare and endemic plants in Mozambique and subsequently evaluate how well represented these hotspots are within the current protected area and IPA networks. We also examine the congruence between IPA and protected areas to identify opportunities for strengthening the conservation of plants in Mozambique. We found that high WEGE scores, representing areas rich in endemic/near-endemic and threatened species, predict the presence of IPAs in Mozambique, but do not predict the presence of protected areas. We also find that there is limited overlap between IPAs and protected areas in Mozambique. We demonstrate how IPAs could be an important tool for ensuring priority sites for plant diversity are included within protected area network expansions, particularly following the adoption of the “30 by 30” target agreed within the post-2020 Convention on Biological Diversity framework, with great potential for this method to be replicated elsewhere in the global tropics.     

A Model for diffusion controlled bioavailability of crude oil components

Crude oil is a complex mixture of several different structural classes of compounds including alkanes, aromatics, heterocyclic polar compounds, and asphaltenes. The rate and extent of microbial degradation of crude oil depends on the interaction between the physical and biochemical properties of the biodegradable compounds and their interactions with the non-biodegradable fraction. In this study we have systematically altered the concentration of non-biodegradable material in the crude oil and analyzed its impact on transport of the biodegradable components of crude oil to the microorganisms. We have also developed a mathematical model that explains and accounts for the dependence of biodegradation of crude oil through a putative bioavailability parameter. Experimental results indicate that as the asphaltene concentration in oil increases, the maximum oxygen uptake in respirometers decreases. The mathematically fitted bioavailability parameter of degradable components of oil also decreases as the asphaltene concentration increases.     

Glutamine Synthetase in Oligodendrocytes and Astrocytes: New Biochemical and Immunocytochemical Evidence

The results of recent immunocytochemical experiments suggest that glutamine synthetase (GS) in the rat CNS may not be confined to astrocytes. In the present study, GS activity was assayed in oligodendrocytes isolated from bovine brain and in oligodendrocytes, astrocytes, and neurons isolated from rat forebrain, and the results were compared with new immunochemical data. Among the cells isolated from rat brain, astrocytes had the highest specific activities of GS, followed by oligodendrocytes. Oligodendrocytes isolated from white matter of bovine brain had GS specific activities almost fivefold higher than those in white matter homogenates. Immunocytochemical staining also showed the presence of GS in both oligodendrocytes and astrocytes in bovine forebrain, in three white-matter regions of rat brain, and in Vibratome sections as well as paraffin sections.     

Nano- and picoplankton growth and production in the Bay of Villefranche sur Mer (N.W. Mediterranean)

Plankton production in the Bay of Villefranche was relatively constant during March and April 1986 but the particle size at which the production occurred was more variable. At the beginning of the study, production was dominated by the larger (ca. 6 m) flagellates but towards the end it was more or less equally divided between the nano- and picoplankton. There were considerable differences in the estimates of population growth rates, depending on the methods used, but on average the population doubling times were close to 12 hours for autotrophs and 24 hours for heterotrophs. As autotrophs do not grow during the night, each population was therefore doubling once per day. It seemed that each of the nanoor picoplankton populations could adversely affect the growth of the others. This could be either by simple predation or by some form of inhibition. Although nutrient levels in the bay were uniformly low, the addition of nutrients did not always stimulate algal growth. The plankton populations seemed to be both in a state of equilibrium and intense ecological competition.     

Glycerol Phosphate Dehydrogenase, Glucose-6-Phosphate Dehydrogenase, and Lactate Dehydrogenase: Activities in Oligodendrocytes, Neurons, Astrocytes, and Myelin Isolated from Developing Rat Brains

Abstract: Glycerol phosphate dehydrogenase (GPDH), glucose-6-phosphate dehydrogenase (G6PDH), and lactate dehydrogenase (LDH) activities were determined in Oligodendrocytes, neurons, and astrocytes isolated from the brains of developing rats. The activity of each enzyme was significantly lower in both neurons and astrocytes than in Oligodendrocytes. The GPDH activity in Oligodendrocytes increased more than 4-fold during development, and at 120 days cells of this type had 1.4-fold the specific activity of forebrain homogenates. The G6PDH activities in Oligodendrocytes from 10-day-old rats were 1.4-fold the activities in the forebrain homogenates. The activities of this enzyme in Oligodendrocytes were progressively lower at later ages, such that at 120 days the cells had 0.8 times the specific activities of homogenates. The Oligodendrocytes had 0.6 times the homogenate activities of LDH at 10 days, and this ratio had decreased to 0.2 by 120 days. These enzymes were also measured in myelin isolated from 20-, 60-, and 120-day-old rats. By 120 days the specific activities of G6PDH and LDH in myelin were <8% of the respective activities in homogenates. The GPDH activity in myelin was, however, at least 20% the specific activity in the homogenates, even in the oldest animals. It is proposed that LDH could be used as a marker for oligodendroglial cytoplasm in subfractions of myelin and in myelin-related membrane vesicles.