Quantitative resistance to barley leaf stripe (Pyrenophora graminea) is dominated by one major locus

A major gene underlying quantitative resistance of barley against Pyrenophora graminea, a seedborne pathogen causing leaf stripe, was mapped with molecular markers in a barley doubled haploid (DH) population derived from the cross Proctor x Nudinka. This quantitative trait locus (QTL) accounts for r ²= 58.5% and was mapped on barley chromosome 1, tightly linked to the naked gene. A second resistance QTL accounting for 29.3% of the variation in the trait was identified on the P arm of barley chromosome 2. Another two minor QTLs were detected by further analysis. None of the QTLs was found in the barley chromosome 2 Vada region studied by Giese et al. (1993).     

Relationship between the grain pattern in the wood,domain pattern and pattern of growth activity in the storeyed cambium of trees

Summary The relationship between the arrangement of cell events occurring in cambium in a definite configuration and the grain pattern of wood was investigated. Taking into consideration the growth activity of fusiform cell ends, a model of a migrating morphogenetic wave determining an event configuration was made. Waves of length =1 m for the periods T=2 years and T=3 years and waves of lengths =l m and =0.04 m for the period T=10 years were considered. On the model, events from successive annual rings, conventionally comprising 10 cell layers each, were summed. In this way, event maps were obtained. For wave =4 mm, the domain pattern on the modelled map was compatible with the grain pattern. The domain pattern for the wave =1 m was impossible to recreate because the wave migrated too fast. In this case, the pattern of event configuration, incompatible with the grain pattern, formed microareas, which were not domains.     

Spontaneous chlorophyll mutants of Pennisetum americanum: Genetics and chlorophyll quantities

Summary Thirteen spontaneously occurring chlorophyll deficient phenotypes have been described and their genetic basis was established. Ten of these — white, white tipped green, patchy white, white virescent, white striping 1, white striping 2, white striping 4, fine striping, chlorina and yellow virescent showed monogenic recessive inheritance and the remaining three — yellow striping, yellow green and light green seedling phenotypes showed digenic recessive inheritance. The genes for (i) white tipped green (wr) and yellow virescent (yv) and (ii) patchy white (pw) and white striping 1 (wst 1) showed independent assortment. Further, the genes for white (w), white tipped green (wr) and yellow virescent (yv) were inherited independently of the gene for hairy leaf margin (Hm).In the mutants — white tipped green, patchy white, white striping 1, white striping 2, fine striping, chlorina, yellow virescent, yellow striping, yellow green and light green phenotypes total quantity of chlorophyll was significantly less than that in the corresponding controls, while in white virescent there was no reduction in the mature stage. For nine of the mutants the quantity of chlorophyll was also estimated in F₁'s (mutant x control green). In F₁'s of six of the mutants — white tip, patchy white, chlorina, yellow virescent, fine striping and yellow striping the quantity of chlorophyll was almost equal to the wild type. In the F₁'s of three of the mutants — white striping 1, white striping 2 and light green an intermediate value between the mutant and wild types was observed. In yellow virescent retarded synthesis of chlorophyll, particularly chlorophyll a was observed in the juvenile stage. Reduced quantity of chlorophyll was associated with defective chloroplasts. In the mutants — white tipped green, white virescent, fine striping, chlorina, yellow striping, yellow green and light green defective plastids were also observed. In patchy white secondary destruction of chlorophylls and the presence of defective plastids were found to be associated with reduced chlorophyll quantity at maturity.Paper chromatographic studies of leaf flavonoids revealed some variation between the inbreds, but there were three common spots, 7, 8 and 9, except for PDP in which the spot 8 was absent. Chlorophyll deficient mutants differed from their respective controls in the absence of one or more of the spots present in the controls and in the presence of new spots in some of the mutants.Most of the chlorophyll mutants showed higher survival rate in the Kharif season than in Rabi season which was attributed to the higher mean day temperature and longer day light period in the Kharif season than in Rabi season.     

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.     

The formation of peptides from the 2′(3′)-glycyl ester of a nucleotide

Summary We have synthesized 2(3)-O-(glycyl)-adenosine-5-(O-methylphos-phate), an analogue of the 3-terminus of aminoacylated tRNA. A 0.4M solution of this compound maintained at pH 8.2, yields 5.5% of diglycine and 11.5% of diketopiperazine, in addition to the hydrolysis products glycine and adenosine-5-(O-methylphosphate). Under the same conditions, glycine ethyl ester reacts much more slowly, but ultimately gives similar yields of diglycine and diketopiperazine.The aminolysis of 2(3)-O-(glycyl)-adenosine-5-(O-methylphosphate) by free glycine is relatively inefficient, but serine reacts 20 times more rapidly and yields up to 50% of N-glycylserine. The prebiotic significance of these reactions is discussed.Abbreviations MepA adenosine-5-(O-methylphosphate) - MepA-gly 2(3)-O-(glycyl)-adenosine-5-(O-methylphosphate) - MepA-bis-gly 2,3-O-(bis-glycyl)-adenosine-5-(O-methylphosphate) - DKP diketopiperazine - gly Et glycine ethyl ester - gly-ser N-glycylserine - O-gly-ser O-glycylserine - O-(gly)-gly-ser O-(glycyl)-glycylserine - Boc-gly N-tert-butyloxycarbonylglycine - MepA-Boc-gly 2(3)-O-(Boc-glycyl)-adenosine-5-(O-methylphosphate) - MepA-bis-Boc-gly 2,3-O-(bis-Boc-glycyl)-adenosine-5(O-methylphosphate) - (gly)₂ diglycine - (gly)₃ triglycine     

Comparative Modulation by 3α,5α and 3β,5β Neurosteroids of GABA Binding Sites During Avian Central Nervous System Development

Neurosteroids are endogenous Central Nervous System (CNS) compounds which act mainly by allosteric modulation of the GABA_A receptor complex. The presence of a 3-hydroxyl group and a 5-hydrogen atom have been found to be essential structural requirements for biological activity in mammals. In the present work we report the enhancing activity on [³H]GABA binding to its receptor sites in chick optic lobe produced by progesterone metabolites 3-hydroxy,5-pregnan-20-one (3,5-P) and 3-hydroxy,5-pregnan-20-one (3,5-P). Both steroids were found able to enhance [³H]GABA binding along ontogeny, displaying a similar profile at early developmental stages, while in adulthood 3,5-P had greater potency (EC₅₀ 0.22 M) and enhancing effect (E_max: 122%). In adult synaptic membranes, the two compounds displayed a complex interaction with the GABA_A receptor, disclosed by a Schild plot with slope below one and an incomplete displacement of 3,5-P by its 3,5 isomer. Such complexity could be related to the steroidogenic profile in avian CNS, with 5-reduced progesterone metabolites present since early development, while 3,5-P is found only in adulthood. Bearing in mind differences between avian and mammalian steroidogenic profiles and the relevance of 5-steroids in early avian development, we propose that 3,5-P, instead of the classical potent 3,5-steroids, may be the endogenous modulator of GABAergic activity in developing avian brain.     

A novel PH-CT-COSY methodology for measuring JPH coupling constants in unlabeled nucleic acids. Application to HIV-2 TAR RNA

A quantitative analysis of J_PH scalar couplings in nucleic acids is difficult due to small couplings to phosphorus, the extreme overlap of the sugar protons and the fast relaxation of the spins involved in the magnetization transfer. Here we present a new methodology that relies on heteronuclear Constant Time Correlation Spectroscopy (CT-COSY). The three vicinal ³J_PH3, ³J_PH5 and ³J_PH5 scalar couplings can be obtained by monitoring the intensity decay of the P_i-H3_{i – 1} peak as a function of the constant time T in a 2D correlation map. The advantage of the new method resides in the possibility of measuring the two ³J_PH5 and ³J_PH5 scalar couplings even in the presence of overlapped H5/H5 resonances, since the quantitative information is extracted from the intensity decay of the P-H3 peak. Moreover, the relaxation of the H3 proton is considerably slower than that of the H5/H5 geminal protons and the commonly populated conformations of the phosphate backbone are associated with large ³J_PH3 couplings and relatively small ³J_{PH5 / H5}. These two facts lead to optimal signal-to-noise ratio for the P-H3 correlation compared to the P-H5/H5 correlation.The heteronuclear CT-COSY experiment is suitable for oligonucleotides in the 10–15 kDa molecular mass range and has been applied to the 30mer HIV-2 TAR RNA. The methodology presented here can be used to measure P-H dipolar couplings (D_PH) as well. We will present qualitative results for the measurement of P-H_base and P-H2 dipolar couplings in the HIV-2 TAR RNA and will discuss the reasons that so far precluded the quantification of the D_PHs for the 30mer RNA.     

Prevalence and molecular heterogeneity of alfa+thalassemia in two tribal populations from Andhra Pradesh,India

Summary We describe here the screening of a small group of apparently healthy individuals belonging to the tribal communities of Koya Dora and Konda Reddi. A remarkably high incidence of deletion and nondeletion ⁺ thalassemia mutants has been found with allele frequencies and distributions characteristic to each tribe. We have confirmed the strict relationship between Hb S levels and the number of globin genes in double heterozygotes for the S gene and thalassemia. In this population sample we did not find either heterozygous carriers of ⁰ thalassemia (deletion of both alpha genes in cis) or individuals showing hemolytic anemia due to inactivation of three -globin genes (Hb H disease). Selection by malaria is most probably responsible for the prevalence of the various ⁺ thalassemia haplotypes among the two tribal populations of Andhra Pradesh.     

13C and 15N depletion in components of a foodweb from an ephemeral boreal wetland compared to boreal lakes: putative evidence for microbial processes

Stable carbon and nitrogen isotope ratios were used to posit the relative importance of microbial processes on energy pathways in an ephemeral, humic boreal wetland compared to four clearwater lakes in northwestern Ontario, Canada. In addition to algae and dipteran larvae, odonate larvae were sampled as these latter organisms are known to predate indiscriminately on smaller invertebrates and are thus likely to have average isotope ratios reflective of their habitats. Similarities in ¹³C and ¹⁵N values between lake insect larvae and emerged adults suggested that littoral foodwebs in these oligotrophic lakes may rely to a considerable degree upon terrestrial carbon. Wetland insect larvae and algae were depleted in both ¹³C and ¹⁵N compared to biota in lakes. Carbon isotope analysis implied a substantial presence of microbial respiration from decomposition in the humic wetland, whereas nitrogen isotope analysis suggested the prevalence of microbially modified nitrogen dynamics, including the possibilty of N-fixation.     

The incorporation and characterization of powdery mildew resistance from Aegilops longissima in common wheat (T. aestivum L.)

Summary In the progeny of a hybrid between monotelosomic line 3B of Chinese Spring wheat and Chinese Spring — Aegilops longissima ditelosomic addition line G a cytologically stable strain was selected consisting of 20 wheat chromosome pairs, one pair of telosomic chromosome 3BL and one pair of telosomic longissima chromosome G. Inoculating Chinese Spring — Aegilops longissima addition and substitution lines with ten different powdery mildew isolates, partial resistance was observed. The infection grade as well as the number of spores/cm² leaf area were significantly reduced.     

Magnetic orientation and magnetoreception in birds and other animals

Animals use the geomagnetic field in many ways: the magnetic vector provides a compass; magnetic intensity and/or inclination play a role as a component of the navigational map, and magnetic conditions of certain regions act as sign posts or triggers, eliciting specific responses. A magnetic compass is widespread among animals, magnetic navigation is indicated e.g. in birds, marine turtles and spiny lobsters and the use of magnetic sign posts has been described for birds and marine turtles. For magnetoreception, two hypotheses are currently discussed, one proposing a chemical compass based on a radical pair mechanism, the other postulating processes involving magnetite particles. The available evidence suggests that birds use both mechanisms, with the radical pair mechanism in the right eye providing directional information and a magnetite-based mechanism in the upper beak providing information on position as component of the map. Behavioral data from other animals indicate a light-dependent compass probably based on a radical pair mechanism in amphibians and a possibly magnetite-based mechanism in mammals. Histological and electrophysiological data suggest a magnetite-based mechanism in the nasal cavities of salmonid fish. Little is known about the parts of the brain where the respective information is processed.     

Mineral impact of lakes as background for their biogenic dynamics

Favourable circumstances for limnological observations were offered by human activities at shores of some Holstein lakes. The lakes were enriched by clay, silt, sandy particles and hydroxides of iron and manganese over many years in consequence of an embankment built at Schöhsee and influx of washing water from a gravel pit, respectively. During windy weather the lakes were extremely turbid, but very clear during calm weather. The 1% penetration level of green light was found at 11 and 14 m. Nutrients as well as small phytoplankton cells and bacteria were adsorbed on to the detritus. Therefore, the sedimentation rate increased and consequently that of phytoplankton production decreased. The sediments became rich in minerals comparable with alpine lakes. The epilimnic decomposition rate was much lower than in normal Holstein lakes in the neighbourhood, as in Groer Plöner See and the highest value 15 of the Short-Circuit-Metabolism (SCM) was measured in Pluss-See, i.e., there occurred 15 times re-use of carbon (and other) molecules in the euphotic region before settling down. The conclusion drawn is that the mineral impact of alpine lakes occurring annually under natural conditions, at least in spring, is one of the most important factors of minor bioactivity compared with eutrophic lowland lakes.     

Two-dimensional 1H NMR study of two cyclobutane type photodimers of thymidylyl-(3′→5′)-thymidine

2D NMR spectroscopy and J coupling constant analysis are applied to resolve the structure of two photoproducts of thymidylyl-(35)-thymidine. These products are cyclobutane type thymine dimers possessing the cis-syn (the predominant one) and trans-syn geometry. The cis-syn is formed in an ANTI-ANTI conformation about the N-glycosyl linkages and resembles the normal base-stacked configuration. The glycosidic conformation in solution of the 5 terminal fragment differs from the crystal in which the less common SYN conformation is observed. In this isomer only the sugar pucker of the 3 terminal fragment is changed substantially with respect to the dinucleotide. The trans-syn isomer is formed in a SYN-ANTI glycosidic conformation. In this isomer the sugar puckers of both deoxyribose rings are affected and a preference for a pure 2-endo conformation is observed.Abbreviations dTpdT 2-deoxythymidylyl-(35)-2-deoxythymidine - dTp[]dT cyclobutane type photodimers of dTpdT - dTp- and dTp[]- their 5' terminal fragments (fragment A) - -pdT and-[]pdT their 3 terminal fragments (fragment B) - RP-HPLC reversed-phase high-performance liquid chromatography - COSY two-dimensional correlated spectroscopy - 2D NOE two-dimensional nuclear Overhauser spectroscopy     

Variation of seed α-amylase inhibitors in the common bean

Variation of seed -amylase inhibitors was investigated in 1 154 cultivated and 726 non-cultivated (wild and weedy) accessions of the common bean, Phaseolus vulgaris L. Four -amylase inhibitor types were recognized based on the inhibtion by seed extracts of the activities of porcine pancreatic -amylase and larval -amylase and larval -amylase of the Mexican bean weevil, Zabrotes subfasciatus Boheman. Of the 1 880 accessions examined most (1 734) were able to inhibit porcine pancreatic -amylase activity, but were inactive against the Z. subfasciatus larval -amylase; 41 inhibited only the larval -amylase activity, 52 inhibited the activities of the two -amylases, and 53 did not inhibit the activity of either of the -amylases. The four different inhibitor types were designated as AI-1, AI2, AI-3, and AI-0, respectively. These four inhibitor types were identified by the banding patterns of seed glycoproteins in the range of 14–20 kDa by using SDSpolyacrylamide gel electrophoresis. Additionally, four different banding patterns were recognized in accessions with AI-1, and were designated as AI-1a, 1b, 1c, and 1d. Two different patterns of the accessions lacking an -amylase inhibitory activity were identified and designated as AI-0a and AI-0b. The largest diversity for seed -amylase inhibitors was observed in non-cultivated accessions collected from Mexico where all eight inhibitor types were detected. The possible relationships between the variation of seed -amylase inhibitors and bruchid resistance are discussed.     

The influence of lactation products on the temporal expression of histo-blood group antigens in the intestines of suckling pigs: lectin histochemical and immunohistochemical analysis

Summary Lectins and carbohydrate-specific monoclonal antibodies were used as cytochemical probes to investigate the possible influence of lactation products on the expression of intestinal membrane and secretory glycoconjugates in suckling piglets. Two different lactational regimes were compared; the first involved normal rearing of piglets for 8 weeks on a single dam and the second involved repeated cross-fostering of littermates onto recently farrowed sows, thereby restricting them to early milk. Five histo-blood group phenotypes were recognized within the piglet population: two immature phenotypes, O immature or Oi and A immature or Ai, and three mature forms, O, A and -. Under the normal suckling regime the transition from immature to mature OA phenotypes was evident at the fifth weekpost partum. However, in the repeatedly cross-fostered piglets this transition was evident much earlier at 3 weekspost partum. It is suggested that qualitative or quantitative variations in milk composition during the sow's lactation may significantly influence the expression of intestinal histo-blood group antigens in her suckling young.Abbreviations GalNac N-acetylgalactosamine - Gal Galactose - GlcNac N-acetylglucosamine     

Structural study of fucoidan from Cladosiphon okamuranus tokida

A structural study was carried out on a fucoidan isolated from the brown seaweed Cladosiphon okamuranus. The polysaccharide contained fucose, glucuronic acid and sulfate in a molar ratio of about 6.1 : 1.0 : 2.9. The results of Smith degradation showed that this polysaccharide has a linear backbone of 13-linked -fucopyranose with a half sulfate substitution at the 4-positions, and a portion of the fucose residues was O-acetylated. The data obtained from partial acid hydrolysis, a methylation analysis and NMR spectra indicated that the -glucuronic acid residue is linked to the 2-positions of the fucose residues, which were not substituted by a sulfate group. These results indicated that the average structure of this fucoidan is as follows: -[(3Fuc-4(±OSO₃-)1–)₅3[GlcA12]Fuc1–]_n–. (Half of each fucose residue was sulfated. One O-acetyl ester was present in every 6 fucose residues.)     

Substitutions of the Conserved Thr42 Increased the Roles of the ε-Subunit of Maize CF1 as CF1 Inhibitor and Proton Gate

The conserved residue Thr42 of -subunit of the chloroplast ATP synthase of maize (Zea mays L.) was substituted with Cys, Arg, and Ile, respectively, through site-directed mutagenesis. The over-expressed and refolded -proteins were purified by chromatography on DEAE-cellulose and FPLC on mono-Q column, which were as biologically active (inhibiting Ca²⁺-ATPase activity and blocking proton gate) as the native subunit isolated from chloroplasts. The T42C and T42R showed higher inhibitory activities on the soluble CF₁(–) Ca²⁺-ATPase than the WT. The T42I inhibited the Ca²⁺-ATPase activity of soluble CF₁ and restored photophosphorylation activity of membrane-bound CF₁ deficient in the most efficiently. Far-ultraviolet CD spectra showed that the portions of -helix and -sheet structures of the three mutants were somewhat different from WT. Thus the conserved residue Thr42 may be important for maintaining the structure and function of the -subunit and the basic functions of the -subunit as far as an inhibitor of Ca²⁺-ATPase and the proton gate are related.     

The aerobic nitrogen-fixingSynechococcus RF-1 containing uncommon polyglucan granules and multiple forms of α-amylase

The aerobic nitrogen-fixing unicellular cyanobacteriumSynechococcus RF-1 (pcc 8801) contains numerous irregular polyglucan granules ranging in size from 0.1 to 0.4 m. These morphologically unusual polyglucan granules are not found in the sheathed nitrogen-fixing unicellular cyanobacteriumGloeothece RF-6 (pcc 8803). Two forms of -amylase, ethyleneglycolbis-(-aminoethyl ether)-N,N,N,N-tetraacetic acid (EGTA)-sensitive and EGTA-insensitive, were found in theSynechococcus RF-1. In addition to their EGTA sensitivity, the two forms of -amylase also differed in their reactive pH range and in their zymogram disc gel electrophoresis. Each form of -amylase was stable and constant in concentration through a diurnal light/dark cycle.     

The contribution of phytoplankton productivity in turbid freshwaters to their trophic status

Certain factors influencing phytoplankton productivity are accentuated in turbid waters. They include mixing, spectral quality shifts, scattering, light fluctuations, and overall light attenuation. Measurements of productivity is influenced by the presence of inorganic turbidity. Together with the above factors high turbidity causes difficulties to assess and model phytoplankton productivity. Estimations of ^B, P_m ^B, I_k and _m only reflect on the physiological condition of the phytoplankton, which differs little between water types of temperate regions. Measurement of integral vertical productivity, efficiency and fractional absorption by the phytoplankton of light energy conversion, however, are greatly influenced by inorganic turbidity. Because of high ratios of mixing to euphotic depth, the critical mixing depth is one of the most important factors influencing overall productivity in turbid waters.     

Plant regeneration from grape callus stored under a combination of low temperature and silicone treatment

Effects of the combination of low temperature and silicone treatment on the storage of grape callus (Vitis vinifera L. x V. labrusca L. cv. Kyoho; V. vinifera L. cv. Koshusanjaku) were examined. In Kyoho, the calli were stored at 10°C successfully for up to 360 days. Embryogenic calli of Koshusanjaku stored at 10°C retained the ability of embryogenesis after 360 days of storage. However, the color of both calli became brownish. This was improved by the combination of low temperature and silicone treatment. The calli of Kyoho survived by the storage under the combination of 15°C and silicone. Embryogenic calli stored at 10 and 15°C in combination with silicone survived for 360 days, and regenerated only after transfer onto a regeneration medium. Thus the combination of low temperature and silicone affects the longevity of the grape callus.