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cDNA-AFLP is one of the techniques developed to study differentially expressed genes. This recent technique is advantageous because it does not need prior sequence knowledge and is reliable due to highly stringent PCR conditions. The traditional cDNA-AFLP method uses radioactively labelled products and is characterised by high sensitivity and resolution. Here, the use of Cy5-labelled primers to detect products on polyacrylamide gels is reported. This non-radioactive method, based on fluorescence, is shown to be faster and the recovery of interesting bands is easier. The study of the differential gene expression of the interaction between potato and Phytophthora infestans was used for the valuation of this method. Different gene expression profiles – such as up-regulation, down-regulation or point expression – were obtained. Moreover, this technique was shown to be highly reproducible.

An unusual lectin possessing two distinctly different types of carbohydrate-combining sites was purified from tubers of Xanthosoma sagittifolium L. by consecutive passage through two affinity columns, i.e. asialofetuin-Sepharose and invertase-Sepharose. SDS-polyacrylamide gel electrophoresis, N-terminal amino acid sequencing, and gel filtration chromatography of the purified lectin showed that the X. sagittifolium lectin is a heterotetrameric protein composed of four 12-kDa subunits (alpha(2)beta(2)) linked by noncovalent bonds. The results obtained by quantitative precipitation and hapten inhibition assays revealed that the lectin has two different types of carbohydrate-combining sites: one type for oligomannoses, which preferentially binds to a cluster of nonreducing terminal alpha1,3-linked mannosyl residues, and the other type for complex N-linked carbohydrates, which best accommodates a non-sialylated, triantennary oligosaccharide with N-acetyllactosamine (i.e. Galbeta1,4GlcNAc-) or lacto-N-biose (i.e. Galbeta1,3GlcNAc-) groups at its three nonreducing termini.

Xenopus oocytes were injected with several heterologous mRNAs to investigate specific message recruitment onto polysomes. When large amounts of mRNA such as ovalbumin, which is translated on membrane-bound polysomes, are injected, most of the stable message accumulates in a postpolysomal supernatant. Conversely, when similar amounts of nonmembrane-bound mRNAs such as those which code for adenovirus protein are injected, most of the messages are found in a polysome pellet. Nonpolysomal mRNAs such as zein, ovalbumin, and lysozyme can be recruited onto membrane-bound polysomes by injected rough endoplasmic reticulum (RER). Only RER, but not Golgi apparatus, plasma membrane, or salt-washed RER has such recruiting ability. In addition, the nontranslating messengers can be recruited by injecting the salt wash of the RER. Since most nontranslating mRNAs sediment to regions less than the 80 S monosome, the step at which translational regulation takes place is probably initiation rather than elongation. The mechanism by which recruitment might occur is discussed.

The resonance in the12C+12C system atEc.m.=19.3 MeV has been studied in the neutron and proton decay channels. From(p, ?), (n, p) and (n, ?) coincidence measurements high spin states could be localized inA=23 nuclei, in23Mg up to possibly 21/2+. These states were resonantly populated. The present data favorJp=17/2+ for the 9.61 MeV state in23Mg and therefore also for the probable parent state at 9.81 MeV in23Na. AJp=12+ assignment to the resonance is supported and evidence was found that the resonant excitation of the lowest 15/2+ and 17/2+ states in mass 23 nuclei is caused by a change of the intrinsic structure of the Yrast levels aroundJp=15/2+ towards larger deformation.

A cell surface protein (Mr 68,000) of the moderately but obligately halophilic phototrophic bacterium Rhodospirillum salexigens was identified by two independent methods: first, by labeling the cell surface with radioactive iodine and lactoperoxidase, and second, by washing cells in 30% sucrose to remove proteins attached to the cell surface by ionic bonds. The identified protein very likely represents the outermost layer of the cell envelope of R. salexigens as observed by electron microscopy. The protein was isolated. Its isoelectric point was determined to be 4.4; the excess of acidic over basic amino acids was found to be 18.3 mol%; and its average hydrophobicity was 2.26 kJ per residue.

Xenopus oocyte-specific poly(A) RNA-binding proteins were isolated and used to prepare monoclonal antibodies. One antibody was used to characterize one particular antigen by immunoblot analysis. The antigen had a molecular weight of 56,000 was oocyte-specific, and decreased in amount during oogenesis. The antigen was localized in the cytoplasm throughout oogenesis and sedimented mainly at 40-60 S. The antigen also was shown to bind poly(A) RNA following chromatography of ribonucleoprotein particles on oligo(dT)-cellulose. The antibody was used to immunoadsorb nontranslating ribonucleoprotein particles. Fifty-five per cent of the poly(A) RNA sedimenting between 40-60 S was shown to be bound by the antigen. The further use of this antibody in attempting to examine other components of the ribonucleoprotein particle is discussed.

The effect of NaCl on poplar shoots grown in vitrowas studied. After 28 days of cultivation on media containing up to 300 mmol/L NaCl, the shoot and root lengths as well as the rooting percentage were smaller than in the control. These effects were enhanced by increasing salinity. Changes in several biochemical markers (soluble proteins, soluble sugars and peroxidase activity) were observed in poplar shoots cultivated for 7 days on salt-supplemented and control media. Measurements showed that the soluble protein content of the plants decreased dramatically on day 1 but stabilized to a constant value thereafter, except for the 300 mmol/L NaCl condition. Peroxidase activity increased with salt content and time of cultivation, except for the 300 mmol/L NaCl condition, where it remained unchanged. Changes were also observed in the contents of glucose, fructose, sucrose and galactose. Glucose and fructose contents strongly increased after 3 days of cultivation on 300 mmol/L NaCl-containing medium. A maximum sucrose content was observed on day 1 for all conditions, followed by a decrease until day 7. Galactose was unaffected by the salt treatments.

Selectively excited high-spin states in27Al have been located by the reaction12C(16O,p)27Al. The excitation functions of these states have been measured at incident energiesEcm=18.7 to 30.1 MeV at intervals of 150 keV. They exhibit maxima of presumably non-statistical origin. At four different energies the subsequent decay of the27Al states has been studied by detecting the final heavy recoils with the Munich recoil spectrometer in coincidence with the proton emitted in the first stage of the reaction. Using this new method branching ratios of the?-, a-, andn-decay have been measured. Based on angular correlation arguments spins up to 27/2h have been determined within the experimental accuracy of 1–2h. The observations suggest a superdeformed shape of27Al at least in some of the states.