Translation of Two Messenger RNAs from Lens in a Cell Free System from Krebs II Ascites Cells

SPECIALIZED tissues which synthesize only a small number of different proteins offer obvious advantages as sources of specific and pure messenger RNAs (mRNAs). Presumptive mRNAs have been isolated and partially characterized from reticulocytes^1,2, muscle³, myelomas⁴ and eye lens⁵. The messenger role of 9S RNA from reticulocytes has been established by its ability to direct the synthesis of haemoglobin in cell-free systems from reticulocytes² and Krebs 11 ascites tumour cells⁶ and in Xenopus oocytes⁷. We show here that 10S and 14S RNA fractions from calf lens direct the synthesis of different polypeptide components of lens crystallin in the ascites cell-free system. These results complement and extend the demonstration, in the accompanying article⁸, that 14S lens RNA is translated in the reticulocyte lysate.     

Further Observations on the Minimum Intercellular Space Carbon-Dioxide Concentration ({Gamma}) of Maize Leaves and the Postulated Roles of 'Photo-respiration' and Glycollate Metabolism

The elevated -values of maize leaves under water strain havebeen found to be due to a reduction in the rate of carbon-dioxideintake during photosynthesis; these -values do not respond tochanges in the concentration of oxygen. No evidence has beenfound of an increased rate of carbon-dioxide evolution fromilluminated maize leaves under water strain (photo-respiration)although the presence of glycollate in these leaves could bedemonstrated.     

Host plant finding in the specialised leaf beetle Cassida canaliculata: an analysis of small-scale movement behaviour

Abstract.  1. Host plant finding in walking herbivorous beetles is still poorly understood. Analysis of small-scale movement patterns under semi-natural conditions can be a useful tool to detect behavioural responses towards host plant cues.
2. In this study, the small-scale movement behaviour of the monophagous leaf beetle Cassida canaliculata Laich. (Coleoptera: Chrysomelidae) was studied in a semi-natural arena ( r = 1 m). In three different settings, a host ( Salvia pratensis L., Lamiales: Lamiaceae), a non-host ( Rumex conglomeratus Murr., Caryophyllales: Polygonaceae), or no plant was presented in the centre of the arena.
3. The beetles showed no differences in the absolute movement variables, straightness and mean walking speed, between the three settings. However, the relative movement variables, mean distance to the centre and mean angular deviation from walking straight to the centre, were significantly smaller when a host plant was offered. Likewise, the angular deviation from walking straight to the centre tended to decline with decreasing distance from the centre. Finally, significantly more beetles were found on the host than on the non-host at the end of all the trials.
4. It is concluded that C. canaliculata is able to recognise its host plant from a distance. Whether olfactory or visual cues (or a combination of both) are used to find the host plant remains to be elucidated by further studies.     

The origin of vertebrates: a hypothesis based on kidney development

The habitat of the earliest vertebrates (craniates) is still being debated. Marine as well as freshwater habitats and anadromous behaviour have been proposed. In contrast, an estuarine origin of vertebrates is suggested here, based on ontogenetic, comparative anatomical and functional data. This approach should resolve inconsistencies between the probable existence of glomeruli in the vertebrate ancestors and the marine habitat of all related extant groups (e.g. urochordates and cephalochordates). The kidney, as the main osmoregulatory organ, must have been developed according to the environmental prerequisites even in stem vertebrates. In the absence of fossil evidence only deductions from contemporary animals are possible. These data indicate that ancestral stem vertebrates probably had well-developed glomeruli, and were capable of at least some ion-exchange between urine and the body. However, they were probably unable to cope with a strong osmotic gradient with respect to their environment. The conclusion is that these animals were osmoconformers at around 300–350 mOsm and therefore were restricted to brackish water.  © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society , 2007, 150 , 435–441.     

Starch and prolamin level in single and double high-lysine barley mutants

At maturity the high-lysine barley (Hordeum vulgare L.) Ris0 mutants 1508, 527 and 29 kernels contained about 20% less starch and twice as much free sugars as the parent varieties Bomi and Carlsberg II. An enhanched effect on starch reduction and free sugar accumulation was observed during kernel development when the single mutants 527 and 29 are combined with the mutant 1508. At maturity, kernels of the double mutants 527/1508 and 29/1508 contained, respectively, 68 and 43% less starch than Bomi. The double mutant 29/1508 kernel had a slightly lower prolamin content than mutant 1508 which is the most prolamin-deficient single mutant. In the double mutant 527/1508, however, an almost complete suppression of prolamin synthesis was observed during kernel development. The percentage of lysine in the seed proteins of the double mutants was about the same as in the most extreme single mutant 1508. Based on the additive effect of the individual high-lysine genes in the double mutants, it is concluded that the influences of these genes on prolamin and starch synthesis are independent.     

Two species of Foraminifera of the genus Turrilina with different wall structure

Two species of the foraminiferal genus Turrilina Andreae, 1844, occurring in the Tertiary beds of Denmark and Holland, can be distinguished by their wall structure only. In consequence it is recommended that the wall structure as a systematic character may in this and similar cases be of specific value only.     

Genotypic differences in embryonic life history traits of Folsomia quadrioculata (Collembola: Isotomidae) across a wide geographical range

1. Life history traits play a central role in adaptation to specific environmental conditions. Egg development time, hatchling, and egg batch size in 10 populations of the soil‐dwelling collembolan species Folsomia quadrioculata (Tullberg, 1871) from diverse habitats across arctic and temperate regions, ranging in latitude from 43 to 81°N were studied. 2. For all traits, 15 °C was used as the reference temperature. Phenotypic plasticity was studied by changing temperature to 10 and 20 °C in hatchling size, and to 20 °C in egg development time. The effect of latitude, climatic zone, and summer temperature at their sites of sampling was tested to address the hypotheses that populations from cooler areas would have (i) a faster temperature‐dependent egg development, (ii) a larger hatchling size, (iii) smaller egg batches and (iv) higher phenotypic plasticity 3. The first and fourth hypothesis were not supported, whereas the second and third were partly supported when including the whole latitudinal gradient, but not within regions. Plasticity showed a complex pattern, including large differences between populations from similar macroclimates and considerable similarity between some populations from contrasting climates. Small effects of latitude and macroclimatic variables emphasised that local climate and microhabitat should be taken into account when evaluating thermal conditions as possible drivers of population‐specific differences in soil‐dwelling ectotherms. 4. There was a trade‐off between egg batch and hatchling sizes. A weak correlation between the population mean egg development time and the mean hatchling size suggested that the populations are, or have been, exposed to differential selection.     

Responsivity amplification by light in phytochrome-mediated induction of chloroplast glyceraldehyde-3-phosphate dehydrogenase (NADP-dependent, EC 1.2.1.13) in the shoot of milo (Sorghum vulgare Pers.)

Abstract. A prolonged light treatment strongly increases responsivity to Pfr in many instances of phytochrome-controlled biogenesis of flavone or cyanidin glycosides. The present investigation deals with the question of whether light also leads to a corresponding increase of responsivity towards Pfr in such photoresponses which are not related to synthesis of flavonoid pigments in outer tissue layers of seedlings. Phytochrome-mediated accumulation of the chloroplast GPD (glyceraldehyde-3-phosphate dehydrogenase, EC 1.2.1.13) was chosen as a response and the milo shoot ( Sorghum vulgare Pers. cv. Weider, hybrid) as an appropriate subject. It was found that responsivity towards Pfr is extremely weak in a dark-grown shoot while prolonged light pretreatments lead to a dramatic increase in responsivity. Blue and UV light are far more effective than red light in eliciting this effect within a few hours. High responsivity is only maintained in the light. When the seedlings are placed in darkness the level of responsivity drops rapidly with a half-life of the order of 2 h. The data allow more complete explanations for intriguing phenomena of plant life under natural light/dark conditions such as shade detection or sensing of light → dark transitions.     

Structure of Protochlorophyll-containing Plastids in the Inner Seed Coat of Pumpkin Seeds (Cucurbita pepo)

The inner seed coat of seeds of Cucurbita pepo L. cv. Ohlsens Enke Köks was used to study the development of protochlorophyll-containing plastids with an abnormal ultrastructural composition. The pumpkins were harvested at different stages during fruit development and they thus contained seeds with different developmental stages. The dry weight of seeds of the developmental stages used varied from 0.04 g to 0.3 g. Such a series of seeds with decreasing water content indicating increasing maturity contained different amounts of protochlorophyll, from 0.20 μg/g fresh weight to 500 μg/g fresh weight. The ultrastructure of the protochlorophyll containing plastids changed greatly during development. In young seeds with a low content of protochlorophyll, regular prolamellar bodies were found and starch grains filled most of the plastids. During development the starch content decreased and the prolamellar bodies increased in size and lost their regularity. During maturation the plastids accumulated plastoglobuli, probably containing protochlorophyll, and finally the internal structure of the prolamellar body tubular complex was lost.