Pre-moult foraging trips and moult locations of Emperor penguins at the Mawson Coast

The movements of nine breeding adult emperor penguins Aptenodytes forsteri from two colonies, Auster (67° 23S 64° 04E) and Taylor Glacier (67° 28S 60° 54E), were determined by satellite telemetry on their pre-moult foraging trips. While preparing for their annual moult the penguins travelled for 22–38 days and reached distances of up to 618 km from the colony. Six of the nine tracked penguins were followed to three different moult locations all to the west of their breeding colonies and near other known emperor penguins colonies, such as Kloa Point (66°38S, 59°23E) and Fold Island (67°17S, 59°23E). Sea-ice conditions changed throughout the tracking period; as the birds travelled north the sea-ice contracted south.     

Sources and inheritance of resistance to leaf curl virus in Lycopersicon

Summary One hundred and twenty-two varieties, lines and wild accessions of Lycopersicon were screened under three different regimes during the autumn/winter season of 1982–83 and 1983–84 for resistance to tomato leaf curl virus (TLCV). L. hirsutum f. glabratum (B6013) and L. hirsutum f. typicum (A1904) proved to be highly resistant to TLCV in all three environments. Various accessions of L. peruvianum were also highly resistant. L. pimpinellifolium (A1921) exhibited no TLCV symptoms within 90 days. Of the cultivated varieties, Acc 99 exhibited the minimim score for susceptibility; AC 142, Collection No. 2, Kalyanpur Angurlata and HS 101 had a low rating for virus incidence. The inheritance of resistance was studied in the interspecific crosses between a TLCV resistant line of L. pimpinellifolium (A1921) and five (HS 101, HS 102, HS 110, Pusa Ruby and Punjab Chhuhara) susceptible cultivars of L. esculentum. Parents, F₁, F₂ and backcross progenies were artificially inoculated with local strains of TLCV using vector the viruliferious whitefly, Bemisia tabaci (Genn.). Data indicated that the resistance of L. pimpinellifolium (A 1921) is monogenic and incompletely dominant over susceptibility.     

Rooting apple cultivars in vitro: Interactions among light,temperature, phloroglucinol and auxin

Delicious apple (Malus domestica Borkh.) and several of its strains, which have been difficult to root in vitro, were successfully propagated with rooting percentages up to 100%. The combination of treatments used to achieve this result included placing the shoots on rooting medium in the dark at 30°C for the first week of the rooting stage, then moving them to a regime of 16 hr light-8 hr dark at 25°C. The rooting medium contained half strength Murashige and Skoog salts plus 1.2 M thiamine HCl, 0.56 mM myo-inositol, 1 mM phloroglucinol (PG), 1.4 M indolebutyric acid (IBA), 1.3 M gibberellic acid (GA₃), 87.6 mM sucrose, and 7 g l^–1 Difco Bacto agar. Dark treatment applied during the proliferation stage (etiolation) was less effective than one applied at the beginning of the rooting stage. The optimum length of dark treatment during rooting was 4 to 7 days. Increasing the temperature from 25°C to 30°C improved rooting of Delicious, Royal Red Delicious, and Vermont Spur Delicious in the absence of PG but generally had less effect in the presence of PG. Further increase in temperature to 35°C stimulated rooting of Royal Red Delicious but reduced rooting of Vermont Spur Delicious. Transfer of the cuttings to auxin-free medium after 1 week had no effect on percentage rooting and increased the number of roots per cutting for only 1 of 4 cultivars tested and then only in the presence of PG. In general PG stimulated rooting of Delicious and its strains, but had no effect on Golden Delicious.     

Genetic analysis of two wheat cultivars, ‘Sonalika’ and ‘WL 711’ for reaction to leaf rust (Puccinia recondita)

Summary Genetic analysis for leaf rust reaction of two widely adapted cultivars, Sonalika and WL 711, has been done using 21 near isogenic Lr lines and rust culture IL004 — avirulent on the two cultivars and all the Lr lines used. The segregation pattern in the F₂ generation indicated the presence of a recessive gene in Sonalika and of a dominant gene in WL 711. These genes in cultivars Sonalika and WL 711 have been identified as Lr 11 and Lr 13, respectively. Gene Lr 13 is no longer effective in WL 711 but it continues to give field resistance in the backgrounds of Chris, Prelude and Thatcher. There has been no significant change in the virulence spectrum of the leaf rust pathogen in India with the release of WL 711. High susceptibility of WL 711 seems to be due to the evolution of more aggressive forms of the pathogen to this cultivar. The gene Lr 11, which behaves as a recessive in Sonalika, was effective against leaf rust when this cultivar was released. The high susceptibility of Sonalika is probably due to an increase in the frequency of race 77 virulent on Lr 11. Lr 11 has shown a dominance reversal in the background of Sonalika. Present results suggest that interaction of resistance genes with the background genotype must be studied for their effective use in breeding programme.     

C(alpha) chemical shift tensors in helical peptides by dipolar-modulated chemical shift recoupling NMR

The C chemical shift tensors of proteins contain information on the backbone conformation. We have determined the magnitude and orientation of the C chemical shift tensors of two peptides with -helical torsion angles: the Ala residue in G*AL (=–65.7°, =–40°), and the Val residue in GG*V (=–81.5°, =–50.7°). The magnitude of the tensors was determined from quasi-static powder patterns recoupled under magic-angle spinning, while the orientation of the tensors was extracted from C–H and C–N dipolar modulated powder patterns. The helical Ala C chemical shift tensor has a span of 36 ppm and an asymmetry parameter of 0.89. Its ₁₁ axis is 116° ± 5° from the C–H bond while the ₂₂ axis is 40° ± 5° from the C–N bond. The Val tensor has an anisotropic span of 25 ppm and an asymmetry parameter of 0.33, both much smaller than the values for -sheet Val found recently (Yao and Hong, 2002). The Val ₃₃ axis is tilted by 115° ± 5° from the C–H bond and 98° ± 5° from the C–N bond. These represent the first completely experimentally determined C chemical shift tensors of helical peptides. Using an icosahedral representation, we compared the experimental chemical shift tensors with quantum chemical calculations and found overall good agreement. These solid-state chemical shift tensors confirm the observation from cross-correlated relaxation experiments that the projection of the C chemical shift tensor onto the C–H bond is much smaller in -helices than in -sheets.     

Viability and activity in readily culturable bacteria: a review and discussion of the practical issues

In microbiology the terms viability and culturability are often equated. However, in recent years the apparently self-contradictory expression viable-but-nonculturable (VBNC) has been applied to cells with various and often poorly defined physiological attributes but which, nonetheless, could not be cultured by methods normally appropriate to the organism concerned. These attributes include apparent cell integrity, the possession of some form of measurable cellular activity and the apparent capacity to regain culturability. We review the evidence relating to putative VBNC cells and stress our view that most of the reports claiming a return to culturability have failed to exclude the regrowth of a limited number of cells which had never lost culturability. We argue that failure to differentiate clearly between use of the terms viability and culturability in an operational versus a conceptual sense is fuelling the current debate, and conclude with a number of proposals that are designed to help clarify the major issues involved. In particular, we suggest an alternative operational terminology that replaces VBNC with expressions that are internally consistent.     

Genotypic variation in the germination of common bean in response to cold temperature stress

Beans (Phaseolus vulgaris) are regarded as a susceptible crop to suboptimal temperatures. In temperate regions, low temperatures reduce establishment of beans when planted early in the growing season. Seeds of 14 cultivars/lines or beans were germinated in petri dishes at a constant 8, 10, 12, or 18°C or at 12 h alternating temperatures of 10/8, 12/8 or 18/8°C. Differences in germination percentages and rates between cultivars/lines were significant, especially at low temperatures. Cultivars/lines that germinated best and quickly at constant 8°C were Volare, Great Northern (G.N.) Tara, G.N. Belneb # 1, G.N. Spinel, and San Cristobal. Germination percent and rate of Pinto-UI-111 and Canadian Wonder increased significantly when temperatures were increased by 2 to 4°C for 12 h per 24 h, compared with a constant 8°C. Whereas, germination of G.N. Belneb # 1 was reduced. Polyacrylamide gel electrophoresis was used to study the effect of cold treatment on polypeptide patterns of seven cultivars/lines. Seeds were germinated at 18°C constant for 96 h or at 18°C for 48 h followed by 48 h at 2 or 8°C. During cold treatment the synthesis of some polypeptides increased. Volare, G.N. Tara Pinto-UI-111 and Canadian Wonder showed changes in polypeptide patterns, while Alubia-33-1, Michigan 84100 and BAT-1225 showed no changes in polypeptide patterns if compared to the control (96 h at 18°C in the dark). This suggests a likely essential role of these proteins in the development of chilling tolerance.     

A new enzymatic route to the synthesis of 12-ketoursodeoxycholic acid

Summary Cholic acid (3,7,12-trihydroxy-5-cholanoic acid) was completely and selectively transformed into 12-ketoursodeoxycholic acid (3,7-dihydroxy-12-oxo-5-cholanoic acid) by means of two consecutive enzymatic steps catalyzed, the first, by 7- and 12-hydroxysteroid dehydrogenase and, the second, by 7-hydroxysteroid dehydrogenase. Coenzyme regeneration was carried out with -ketoglutarate-glutamate dehydrogenase and glucose-glucose dehydrogenase, respectively.     

On morphological variation in Keratella cochlearis populations from Holstein lakes (Northern Germany)

Keratella cochlearis occurs in many Holstein lakes (northern Germany) as three well defined and separated forms: cochlearis, hispida, and tecta, each showing very little variation between the lakes. The present data show that the tecta form did not originate from a Lauterborn cycle.     

Kinetic studies of peptide bond formation. Effect of chloramphenicol

There might be an undetermined order in the interaction of the substrates with the ribosomes in the reaction of CACCA-Leu-Ac with puromycin to form Ac-Leu-puromycin and CACCA (fragment reaction). Km 0°=6×10^-4 M for the puromycin · ribosome interaction. Chloramphenicol totally blocks the fragment reaction as a consequence of a single interaction with the ribosome of Kd 0°=2.2×10^-6 M. The inhibition by chloramphenicol of the fragment reaction is mixed competitive for puromycin.     

Production of thermostable amylolytic enzymes by Thermococcus hydrothermalis

A cell extract of Thermococcus hydrothermalis, grown for 6 h, gave -glucosidase activity at 14.9 U/l, degrading oligosaccharides and maltose. -Amylase, -glucosidase and pullulanase activities were detected at 289 U/l, 13.5 U/l and 30 U/l respectively in the culture medium after 24 h growth of the archaeum. All of three enzymes, characterised by a half-life time of 1 to 5 h at 95°C, degraded both the (14) and (16) linkages of polysaccharides and the (14) linkages of oligosaccharides. © Rapid Science Ltd. 1998     

Purification and some properties of Α-amylase from an ectomycorrhizal fungus, <Emphasis Type="Italic">Tricholoma matsutake</Emphasis>

-Amylase from a still culture filtrate of Tricholoma matsutake, an ectomycorrhizal fungus, was isolated and characterized. The enzyme was purified to a homogeneous preparation with Toyopearl-DEAE, gel filtration, and Mono Q column chromatography. The -amylase was highly purified (3580 fold) with a recovery of 10.5% and showed a single protein band by SDS-PAGE. The enzyme was most active at pH 5.0–6.0 toward soluble starch and stable within the broad pH range 4.0–10.0. This -amylase was a relatively thermostable enzyme (optimum temperature, 60°C; thermal stability, 50°C). The molecular mass was 34kDa by size-exclusion chromatography and 46kDa by SDS-PAGE. This enzyme was not inhibited by the Hg²⁺ ion. Measurement of viscosity and TLC and HPLC analysis of the hydrolysates obtained from amylose showed that the amylase from T. matsutake is an endo-type (-amylase). Substrate specificity was tested using amylose with different polysaccharides. This -amylase readily hydrolyzed the -1,4 glucoside bond in soluble starch and amylose A (MW, 2900), but did not hydrolyze the -1,6 bond and cyclic polysaccharides such as - and -cyclodextrin.     

Genetic control of heading date and spikelet number in common wheat (T. aestivum L.) line ‘Noa’

Summary The phenology and build-up of spikelet number under 10 h day-length were studied in five wheat lines: the multispikelet line Noa, the regular line Mara, the F₁ hybrid between them and monosomics 2D of Mara and of this hybrid (lacking the 2D chromosome of Mara). Noa had a longer spike development phase, a higher initial number of spikelet primordia and a slower rate of spikelet production than Mara. The F₁ hybrid was similar to Noa in its high initial number of spikelets and to Mara in its high rate of spikelet production. This hybrid had a shorter spikelet phase than both parents. Deletion of one dose of the Mara 2D chromosome from either Mara or the F₁ hybrid caused a reduction in the rate of spikelet production and an increase in the duration of the spikelet phase. These effects were due to the reduced dosage of the 2D chromosome. However, in the F₁ hybrid this deletion also caused an increase in the spike development phase — an indication that Noa carries on its 2D chromosome a recessive gene for late heading date which acts on the spike development phase. This gene of Noa is independent of the day-length sensitive gene ppd, and is different from Noas dominant gene for large initial number of spikelets.     

Influence of photoperiod,temperature and host plant on the production of diapause eggs inPetrobia (Tetranychina) harti (Acari: Tetranychidae)

Petrobia harti (Ewing) diapauses in the egg stage. Adult females lay either diapause or nondiapause eggs. On the University of Thessaloniki campus (41°N), the mite was found to develop on leaves ofOxalis corniculata L. throughout the year, while no mites were found on leaves ofOxalis articulata Savigny growing in the same area. In the laboratory the mite could be maintained equally well on detached leaves of both plant species, kept on wet cotton-wool.Forty to 90% females laying diapause eggs (dlf) were produced when the mites developed under LD 1212 and 19±1 °C, or LD 168 and 19±1 °C or 25±1 °C on leaves ofO. articulata detached from plants grown in the open in various seasons. Under the same conditions, a very low to zero percentage ofdlf was produced onO. corniculata. By rearing certain feeding stages on one of these twoOxalis hosts, and the other feeding stages on the other host, various percentages ofdlf were obtained. These percentages were the net effect of the antagonistic action of the twoOxalis species.By rearing the mites at LD 8.515.5, LD 1212 or LD 168 and a temperature of 19±1 °C onO. articulata leaves renewed every 3 days, or every 16–18 days, or not at all, it could be shown that diapause induction or aversion is caused by the direct effect of photoperiod on the mites, and not by an effect through the host leaves.When wholeO. articulata plants were grown under LD 168 and 19±1 °C in the laboratory, or developed in the open during April and May, flowers were produced, while under LD 1212 no flowering occurred. In the laboratory under diapause-inducing conditions, higher percentages ofdlf were produced on leaves detached from flowering plants than on leaves detached from plants not flowering.OnO. articulata leaves at 20 °C, photoperiods with photophases equal to or longer than 12 h induced from 70 to 80%dlf, while photoperiods with photophases equal to or shorter than 10.9 h induced very low to zero percentages. By transferring different chrysalis stages from a diapause-inducing (LD 1212) to a diapause-averting (LD 8.515.5) photoperiod, and vice versa, it was found that the nymphochrysalis through deutonymph stages were sensitive to photoperiod, the deutochrysalis and deutonymph being the most sensitive.Under an LD 1212 photoperiod, a temperature of 20 °C induced diapause, whereas 25 °C, 30 °C, or a daynight thermoperiod of 25 °C18 °C suppressed it.     

Pigeon navigation: Site simulation by means of atmospheric odours

Summary 10 experiments were conducted in which a group of experimental pigeons were allowed to smell natural ambient air for a period of 3 h at a site which was 25–55 km away from the loft (false site) and then subsequently released at another site ( true release site ) situated in a roughly diametrical position from home. Controls were directly transported to the true release site, and during the same 3 h period they were allowed to smell natural air there. Except for those 3 h, both controls and experimentals were prevented from smelling atmospheric odours by filtration of the air flowing through the containers in which the birds were held. Air filtration was never interrupted in a third group of birds, which were transported together with the experimentals. All the birds were released under local anaesthesia of their olfactory mucosae. Experiments were performed in pairs: Within each pair of experiments, the site used as false site in the first experiment was the true release site in the second and vice versa.On average, initial bearings of the controls were homeward oriented. Bearings of experimentals, which smelled natural air at the false site, were oriented, with similar accuracy, towards a compass direction pointing from this false site to home, and hence these birds actually flew predominantly away from home (Fig. 4). The third group of pigeons, which never could smell natural air, differed from both of the others in their initial orientation.Faster homing speeds were significantly more frequent in the controls than in the other two treatment types. Experimentals that had smelled falsesite odours were slowest.Thus, pigeons not only can be prevented from orienting their courses homeward by elimination of certain substances from the breathing air, but they also can be systematically misguided by false olfactory information.There was no indication that site-specific stimuli independent of olfaction might additionally be necessary for site localization in pigeons.     

Mutagenic effectiveness and efficiency of EMS,DES and gamma-rays in rice

Summary Data on chlorophyll mutation frequency after treatment with EMS, DES and gamma-rays and sequential administration of gamma-rays and the two alkylating agents in three varieties of rice have been used to work out quantitatively the effectiveness and efficiency of each mutagen and combination treatment. For effectiveness, the order is EMS > DES and for efficiency it is EMS > DES > gamma-rays. In some sequential treatments (Gamma-rays + DES in IR8 and Basmati; DES + gamma-rays in IR8 and Jhona; Gamma-rays + EMS in IR8 and Basmati; and EMS + gamma-rays in IR8, Jhona and Basmati) mutation frequency is more than additive (synergistic) but these treatments are decisively less efficient because of their relatively high injurious effects in the M₁. generation. EMS induces more albinas than gamma-rays do. The mutational spectrum patterns induced by gamma-rays and DES are alike. In general, combination treatments tend to increase the frequency of albinas over other types of chlorophyll mutants.     

Differential susceptibility in some sorghum (Sorghum vulgar) genotypes to zinc deficiency in soil

Summary Nine genotypes of sorghum were screened for their relative susceptibility to zinc deficiency in soil. All the varieties were highly responsive to zinc application, but behaved differently under zinc stress conditions in respect of dry-matter production, zinc concentration and uptake. The varieties, JS-263, 29/1, JS-20 and Son 127×SL-245 and CSH-1 were relatively more susceptible to zinc deficiency than 3677×6352, Son 3×SL 209, CSH-3 and 2077×1151. re]19730102     

Trehalose synthesis from maltose by a thermostable trehalose synthase from Thermus caldophilus

Purified trehalose synthase from Thermus caldophilus GK24 produced 18–86% trehalose from 10 mM–1 M maltose. The enzyme also catalyzed the conversion of ,-trehalose into maltose but did not act on other disaccharides. The yield of trehalose from maltose by this enzyme increased 30% more at 40°C than at 80°C and was independent of the substrate concentration. The maximum yield of ,-trehalose from 10 mM maltose reached 86% at 40°C. In addition, ,-trehalose was also formed from maltose or ,-trehalose at 3.5% yield at 80°C. © Rapid Science Ltd. 1998     

Soybean seedling emergence at high temperatures

Bragg and Cobb soybean [Glycine max (L.) Merr.] seeds were germinated in sand at temperatures ranging from 25 to 40°C. Emergence decreased with increasing temperature above 37°C, with virtually no emergence at 40°C. Emergence of 12 other cultivars at 38°C ranged from 25 to 95%. Foster and Coker 338 were more sensitive to high temperature than the other cultivars.     

High-level Expression of Maize <Emphasis Type="Italic">γ</Emphasis>-zein Protein in Transgenic Soybean (<Emphasis Type="Italic">Glycine max</Emphasis>)

Primers were developed for 118 microsatellites isolated from grape (Vitis vinifera) genomic libraries enriched for (AC)n repeats. Only one microsatellite sequence matched other grape SSR-sequences in the GeneBank database. Genotyping was carried out in the parental lines and four offspring of two pseudo-test-cross populations, Cabernet Sauvignon x Seyval and Chardonnay x Bianca, and a further six other grape genotypes (V. vinifera Sultanina, Merlot, Syrah, Müller-Thurgau, Vitis Regent and V. riparia Gloire de Montpellier). A total of 108 microsatellites showed easily scorable alleles and 100 of them segregated according to a configuration suitable for mapping in either cross. A further 8 SSRs, although unsuitable for mapping in those crosses, showed polymorphism in the other genotypes tested. This set of markers was used, along with 75 microsatellites of other repeat-types, to fingerprint 46 offspring of the cross Chardonnay x Bianca. For each full-sib, individual heterozygosity and distance in repeat units between pairs of alleles at each locus (mean d²) were calculated as a tool for predicting highly outbred recombinant individuals. Six microsatellites with segregation ratios significantly distorted towards the lack of homozygous sibs were identified and mapped to linkage groups LG 3 and LG 5. Estimation of heterozygosity at genome-wide level and genotyping at loci for which homozygous sibs are discriminated against are discussed for marker-assisted background selection in outcrossing grapevines.