Below-ground biomass in healthy and impaired salt marshes

Twelve salt marshes in south Louisiana (USA) were classified as either impaired or healthy before a summer sample collection of above- and below-ground biomass and determination of sediment accretion rates. The above-ground biomass of plant tissues was the same at both impaired and healthy salt marshes and was not a good predictor of marsh health. However, below-ground root biomass in the upper 30cm was much lower in the impaired marshes compared to the healthy marshes. Compromises to root production apparently occur before there is an obvious consequence to the above-ground biomass, which may quickly collapse before remedial action can be taken. The subsequent change in vertical position of the marsh surface may be equivalent to many years of accretion, and be irreversible within decades without considerable effort. These results are consistent with the hypothesis that it is the plants below-ground accumulation of organic matter, not inorganic matter that governs the maintenance of salt marsh ecosystem in the vertical plane. Reversing the precursor conditions leading to marsh stress before the collapse of the above-ground biomass occurs is therefore a prudent management objective and could be easier than restoration.     

The association of the human ε-globin gene with the nuclear matrix: a reconsideration

The association of the human -globin gene with the nuclear matrix was studied in erythroid and non-erythroid cell lines. Using a high salt method to prepare histone depleted nuclei we studied the association of variety of fragments covering a 7.8 kb region which contains the human -globin gene. We furthermore studied the association of a set of DNA fragments covering the 13 kb human G/A-globin gene domain, the 16 kb /-globin gene domain and the 10 kb -globin gene domain with the nuclear matrix of K562 and Raji cells. The results show that all fragments studied are easily released from the nuclear matrix, indicating no specific association.Summarizing our results we could say that a region starting 5.7 kb 5 to the human -globin gene and ending 4 kb 3 to the human -globin gene seems to contain no attachment sites with the nuclear matrix of both erythroid and non-erythroid cells.     

The catalysis of nucleotide polymerization by compounds of divalent lead

Summary Soluble lead salts and a number of lead-containing minerals catalyze the formation of oligonucleotides from nucleoside 5-phosphorimidazolides. The effectiveness of lead compounds correlates strongly with their solubility. Under optimal conditions we were able to obtain 18% of pentamer and higher oligomers from ImpA. Reactions involving ImpU gave smaller yields.Abbreviations A adenosine - U uridine - Im imidazole - MeIm 1-methyl-imidazole - EDTA ethylenediaminetetraacetic acid - pA adenosine 5-phosphate - pU uridine 5-phosphate - Ap adenosine cyclic 2:3-phosphate - ATP adenosine 5-triphosphate - AppA P₁,P₂-diadenosine 5-diphosphate - pNp (N = A,U) nucleotide 2(3), 5-diphosphate - ImpA adenosine 5-phosphoreimidazolide - ImpU uridine 5-phosphorimidazolide - A ²pA adenylyl-[25]-adenosine - A ³pA adenylyl-[35]-adenosine - pA ²pA 5-phospho-adenylyl-[25]-adenosine - pA ³pA 5-phospho-adenylyl-[35]-adenosine - pUpU 5-phospho-uridylyl-uridine - pApU 5-phospho-adenylyl-uridine - pUpA 5-phospho-uridylyladenine - (pA)n (n, 2,3,4,) oligoadenylates with 5 terminal phosphate - ImpApA 5-phosphorimidazolide of adenylyl adenosine - (pA) ₅₊ pentamer and higher oligoadenylates with 5 terminal phosphate - (Ap)nA (n = 2,3,4) oligoadenylates without terminal phosphates In the following we do not specify the nature of the internucleotide linkageIn the following we do not specify the nature of the internucleotide linkage     

Effect of mutant host RNA polymerase on the bifunctional activities of P22 gene c1.

Summary A phage has been isolated which specifically transduces the Escherichia coli pheS and pheT genes coding for the and subunits of the phenylalanyl-tRNA synthetase (PRS). This phage transduces with high frequency (i) several temperaturesensitive PRS mutants to thermoresistance and (ii) a p-fluorophenylalanine resistant PRS mutant to sensitivity against this amino-acid analog. The in vitro PRS activities of such lysogens suggest that the and subunits coded by the transducing phage complement the mutant host PRS-subunits in vivo by means of formation of hybrid enzymes.The transducing phages were also used to infect UV light irradiated cells. The SDS-gel electrophoretic analysis of the proteins synthesized in such cells revealed that the phage codes at least for four different E. coli proteins. Two proteins with molecular weights of 94,000 and 38,000 daltons cross-reacted with an anti PRS serum and were thus identified as the and subunits of PRS, respectively. A third protein with w molecular weight of 22,000 daltons is identical with the ribosomal initiation factor IF3 (Springer et al., 1977b). The other protein (M_r 78,000) is still unidentified.     

Plant and insect diversity along a pollution gradient: understanding species richness across trophic levels

We analysed species richness of plants and true bugs (Insecta, Heteroptera) along a pollution gradient in Scots pine stands in Central Germany. As a consequence of particulate deposition, pH-values of soils increased in the vicinity of the emission source. Therefore, emission increased productivity. Species richness of plants increased with decreasing distance from emission source, and thus with increasing productivity. Similarly, species richness of herbivorous Heteroptera increased with decreasing distance from emission source, whereas, surprisingly, abundance decreased. The proportion of specialised herbivorous bug species is largest in the vicinity of the emission source. Thus, the diversity pattern of herbivores may be explained by the specialisation hypothesis and not the consumer rarity hypothesis. Species richness and abundance of carnivorous Heteroptera showed no significant trend along the gradient. Overall our data favour the bottom-up control of species diversity in the analysed system.     

Refinement of the protein backbone angle ψ in NMR structure calculations

Cross-correlated relaxation rates involving the C-H dipolar interaction and the carbonyl (C) chemical shift anisotropy (CSA) have been measured using two complementary 3D experiments. We show that the protein backbone angle can be directly refined against such cross-correlated relaxation rates (^{H C,C}) and the three-bond H/D isotope effect on the C chemical shifts (³C _(ND)). By simultaneously using both experimental parameters as restraints during NMR structure calculations, a unique value for the backbone angle is defined. We have applied the new refinement method to the -Spectrin SH3 domain (a -sheet protein) and to the Sgs1p HRDC domain (an -helical protein) and show that the quality of the NMR structures is substantially improved, judging from the atomic coordinate precision and the Ramachandran map. In addition, the -refined NMR structures of the SH3 domain deviate less from the 1.8 Å crystal structure, suggesting an improved accuracy. The proposed refinement method can be used to significantly improve the quality of NMR structures and will be applicable to larger proteins.     

Combination of immunological and lectin reactions in affinity histochemistry: Proposition of the term affinitin

Summary Using the series system cell receptormistletoe lectin antiferritin-antibodyferritin, the possibilities for combination of lectin and immunological reactions for histochemistry are discussed.The system cell antigen antibody labelled mistletoe (or other) lectin is recommended for visualization of cell antigens (mistletoe lectin as common immunoglobulin reagent). It is pointed out that lectin reactions do not belong to immunhistochemistry but to affinity histochemistry. For all receptor specific proteins (antibodies, lectins, enzymes, haptoglobin and other) the term affinitin is proposed. In consideration of this new definition a common scheme is formulated: Affinitin reacts with affinitin receptor forming affinity product.     

Characterization of ribonucleic acid synthesis by nuclei isolated from Zea mays

Nuclei were isolated from the shoots of Zea mays and assayed for endogenous RNA polymerase activity in vitro. Maximum incorporation from radioactive precursors (70 pmol [³H]uridine 5 monophosphate/100 g DNA) was reached after incubation for 1 h at 25°C. The RNA product, analysed by polyacrylamide gel electrophoresis, was polydisperse in size with an upper limit of 2x10⁶ daltons. Discrete peaks of rRNA were not detected, probably because of endogenous ribonuclease activity. The inclusion of -amanitin (4 g/ml) in the incubation reduced the total incorporation by approximately 40% but did not significantly alter the size of the RNA product. Although 40% of the total activity could be attributed to RNA polymerase II, [³H]RNA synthesised in vitro was found not to contain long sequences of poly (A).Abbreviations oligo (dT) oligo (deoxythymidylic acid) - poly (A) poly (adenylic acid) - GTP guanosine 5 triphosphate - ATP adenosine 5 triphosphate - CTP cytidine 5 triphosphate - UTP utidine 5 triphosphate - UMP uridine 5 monophosphate - PPO 2,5-diphenyloxazole - POPOP 1,4-di-2-(5-phenyloxazolyl) benzene     

RAPD analysis of somaclonal variants derived from embryo callus cultures of peach

Peach [Prunus persica (L.) Batsch] regenerants from cv Sunhigh embryo no. 156, regenerants obtained from cv Redhaven embryo no. 30, and two peach cultivars Sunhigh and Redhaven, were screened for polymorphic RAPD (Random Amplified Polymorphic DNA) markers with up to 60 10-mer primers. Although 35 primers produced results with scoreable bands, only 10 of the primers revealed polymorphism for regenerants of embryo no. 156 and cv Sunhigh, and 1 revealed a low level of polymorphism for regenerants of embryo no. 30 and cv Redhaven. This study demonstrates the feasibility of using RAPD markers to identify somaclonal variants of peach and provides evidence for the existence of genetic differences among these variants.Abbreviations PCR Polymerase chain reaction - RAPD random amplified polymorphic DNA - RFLP Restriction fragment length polymorphism - CTAB cetyltrimethyl ammonium bromide - PVP polyvinyl pyrolidone - dNTP deoxy-ribonucleotide triphosphate Communicated by R. N. Trigiano     

Purification and characterization of (1→3, 1→4)-β-glucan endohydrolases from germinated wheat (Triticum aestivum)

A (13, 14)--glucan 4-glucanohydrolase [(13, 14)--glucanase, EC 3.2.1.73] was purified to homogeneity from extracts of germinated wheat grain. The enzyme, which was identified as an endohydrolase on the basis of oligosaccharide products released from a (13, 14)--glucan substrate, has an apparent pI of 8.2 and an apparent molecular mass of 30 kDa. Western blot analyses with specific monoclonal antibodies indicated that the enzyme is related to (13, 14)--glucanase isoenzyme EI from barley. The complete primary structure of the wheat (13, 14)--glucanase has been deduced from nucleotide sequence analysis of cDNAs isolated from a library prepared using poly(A)⁺ RNA from gibberellic acid-treated wheat aleurone layers. One cDNA, designated LW2, is 1426 nucleotide pairs in length and encodes a 306 amino acid enzyme, together with a NH₂-terminal signal peptide of 28 amino acid residues. The mature polypeptide encoded by this cDNA has a molecular mass of 32085 and a predicted pI of 8.1. The other cDNA, designated LW1, carries a 109 nucleotide pair sequence at its 5 end that is characteristic of plant introns and therefore appears to have been synthesized from an incompletely processed mRNA. Comparison of the coding and 3-untranslated regions of the two cDNAs reveals 31 nucleotide substitutions, but none of these result in amino acid substitutions. Thus, the cDNAs encode enzymes with identical primary structures, but their corresponding mRNAs may have originated from homeologous chromosomes in the hexaploid wheat genome.     

5′-AMP hydrolysis by suspensions and homogenates of pancreatic islet cells from normal and cortisone-treated rats

Summary Suspensions of endocrine pancreas cells were prepared by shaking collagenase-isolated rat islets of Langerhans in calcium-free buffer. When incubated with 1.0 mM substrate at pH 7.4, the cells split,P _i from 5-AMP at a rate of 87 nmol/h per g DNA, and from-glycerophosphate at a rate of 25 nmol/h per g DNAK _m for 5 AMP was about 54 M. Adenosine or theophylline inhibited the 5-AMP hydrolysis. Homogenization of the cells increased the activity toward 5-AMP by 23% and that toward-glycerophosphate by 115%. Injecting rats with cortisone had no effect on the 5-AMP hydrolysis by whole cells but significantly increased the activity in cell homogenates; the intracellular activity toward 5-AMP was more than doubled by the cortisone treatment. Staining whole islet cells for 5-AMP-splitting activity resulted in a demarcation of the cell periphery in control rats. Cells from cortisone-treated rats showed heavier deposits of reaction product, and their cell periphery did not stand out as clearly. It is suggested that 5-nucleotidase is largely an ectoenzyme in normal rat islet cells. The cells also contain an as yet unidentified intracellular phosphatase that seems to be solely responsible for the increased hydrolysis of 5-AMP in cortisone-treated rats.     

Pyridoxal-5′-phosphate derivatives of substance P: Preparation,spasmogenic activity,and degradation by human plasma

Two fluorescent derivatives of substance P (SP) (Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Met-NH₂) were prepared by chemical modification of the native peptide by pyridoxal-5-phosphate (pyridoxal-P). The formation of both pyridoxal-P-derivatives of SP is the result of one modification procedure. The determination of the amino acid composition showed that in one of the derivatives the -amino group of the Lys residue [-(P-pxy)-SP] and in the other the -amino group of the Lys residue and also the N-terminal amino group [,-di-(P-pxy)-SP] of SP had been substituted by pyridoxal-P. -(P-pxy)-SP and ,-di-(P-pxy)-SP have spasmogenic activity with ED₅₀ of 1.8×10^–9 and 4×10^–9 M, respectively, tested on isolated guinea pig ileum. The fluorescence of P-pxy residues permits detection of as little as 1 pmol/ml of -(P-pxy)-SP and 0.5 pmol/ml of ,-di-(P-pxy)-SP. Both analogues of SP obtained are degraded by human plasma more slowly than the native peptide.Abbreviations SP substance P - pyridoxal-P pyridoxal-5-phosphate - P-pxy phospho-pyridoxyl residue - -(P-pxy)-SP substance P modified by pyridoxal-P at the -amino group of the Lys residue - ,-di-(P-pxy)-SP substance P modified by pyridoxal-P at the -amino group of the Lys residue and the N-terminal amino group of SP - (P-pxy)-Lys Lys modified by pyridoxal-P at the -amino group     

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.     

Exploiting selective genotyping to study genetic diversity of resistance to Fusarium head blight in barley

Numerous barley cultivars from around the world have been identified as potential sources of Fusarium head blight (FHB) resistance genes. All of these cultivars exhibit partial resistance, and several mapping studies have shown that resistance to FHB is controlled by multiple genes. Successful development of barley cultivars with high levels of FHB resistance will require combining genes from multiple sources. We characterized five potential new sources of FHB resistance (AC Oxbow, Atahualpa, HOR211, PFC88209, and Zhedar#1) to determine if they contain new FHB resistance genes. Cluster analysis, using a set of 80 SSR markers distributed throughout the genome, showed that most of the new sources of resistance were not similar to three cultivars that have been used in previous FHB mapping studies (Chevron, Frederickson, and Gobernadora), with Atahualpa and HOR211 being the most dissimilar. By selective genotyping, we determined whether markers linked to six known FHB resistance quantitative trait loci (QTLs), discovered in other genotypes, explained variation for resistance in advanced breeding populations created from the new sources of resistance. Markers linked to four of the six known QTLs were associated with FHB severity in at least one of the populations. However, none of the six QTL regions were associated with variation for FHB severity in populations derived from crosses that utilized sources of resistance HOR211 or PFC88209. Selective genotyping is an efficient method for breeders to utilize current QTL information about disease resistance to search for new resistance genes.     

Predominance and tissue specificity of adenine methylation in rice

Summary Using A and C methylation-specific restriction enzymes, namely, MboI, Sau3AI, DpnI, MspI, and HpaII, total rice cv Basmati 370 DNA, repetitive DNAs, and a specific repeat sequence indicated an abundance of adenine methylation. Although cytosine methylation in 5-CCGG-3 sequences suggested more CpC methylation than CpG, the C methylation in sequence 5-GATC-3 was comparatively less than A methylation. Furthermore, the presence of adenine methylation was tissue specific; it was predominant in rice shoot DNA as compared to embryo DNA. This pattern was also observed in two other cultivars of rice, i.e., R-24 and Sona, and was again confirmed using a cloned probe of a specific repeat sequence. Besides the changes in adenine methylation, there was also a qualitative change in 5mC from CpG to CpC dinucleotides in these two tissue systems.     

Ganglioside-cholera toxin interactions: a binding and lipid monolayer study

Summary On t.l.c. plates ¹²⁵I-cholera toxin binds to a disialoganglioside tentatively identified as GD_lb with about 10 times less capacity than to ganglioside GM₁. Binding of labeled toxin to both gangliosides was abolished in presence of excess amounts of unlabeled B subunit. Ganglioside extracts from human or pig intestinal mucosa showed toxin binding to gangliosides GM₁ and GD_1b. In ganglioside-containing lipid monolayers the penetration of the toxin was independent of the ganglioside binding capacity.Abbreviations GM₂ Gal-NAc14Gal(3-2NeuAc)14G1c1Cer - GM₁ Gal3Ga1-NAc14Gal(32NeuAc)14G1c11Cer - GD_1a NeuAc23Ga113Gal-NAc14Gal(32NeuAc)14G1c11Cer - GD1b Gall3Gal-NAcl4Gal(32NeuAc82NeuAc)14Glc11Cer - GT_1b NeuAc23Ga113Ga1-NAcal4Gal(3-2NeuAc82NeuAc)14G1c11Cer - dpPC 1,2-hexadecanoyl-sn-glycero-3-phosphocholine - dpPE 1,2-hexadecanoyl-sn-glycero-3-phosphoethanolamine     

Meiosis and fertility of F1 hybrids between hexaploid bread wheat and decaploid tall wheatgrass (Thinopyrum ponticum)

As the first step in the transfer of barely yellow dwarf virus resistance and salt tolerance from decaploid tall wheatgrass (Thinopyrum ponticum) into hexaploid bread wheat (Triticum aestivum L.), octoploid intergeneric hybrids (2n = 8x = 56) were synthesized by crossing the tall wheatgrass cultivar Alkar with wheat cvs. Fukuhokomugi (Fuko) and Chinese Spring. (Fuko x Alkar) F₁ hybrids were studied in detail. The F₁ hybrids were perennial and generally resembled the male wheatgrass parent with regard to morphological features and gliadin profile. Most hybrids were euploid with 56 chromosomes and showed high chromosome pairing. On an average, in 6 hybrids 83.6% of the complement showed chiasmatic association, some between wheat and wheatgrass chromosomes. Such a high homoeologous pairing would be obtained if Ph1, the major homoeologous pairing suppressor in wheat, was somehow inactivated. Some of the Fuko x Alkar hybrids had high pollen fertility (18.5–42.0% with a mean of 31.5%) and high seed fertility (3–29 seeds wtih a mean of 12.3 seeds per spike), offering excellent opportunities for their direct backcrossing onto the wheat parent.     

Differential desensitization properties of rat neuronal nicotinic acetylcholine receptor subunit combinations expressed inXenopus laevis oocytes

Summary 1. Chronic administration of nicotine up-regulates mammalian neuronal nicotinic acetylcholine receptors (nAChRs). A key hypothesis that explains up-regulation assumes that nicotine induces desensitization of receptor function. This is correlated with behaviorally expressed tolerance to the drug.2. The present experiments were conducted to: (a) obtain information on the nicotine-induced desensitization of neuronal nAChR function, a less understood phenomenon as compared to that of the muscle and electric fish receptor counterparts; (b) test the hypothesis that different receptor subunit combinations exhibit distinct desensitization patterns.3.Xenopus laevis oocytes were injected with mRNAs encoding rat receptor subunits2,3, or4 in pairwise combination with the2 subunit. The responses to various concentrations of acetylcholine (ACh) or nicotine were analyzed by the two electrode voltage clamp technique.4. Concentration-effect curves showed that nicotine was more potent than ACh for all the receptor subunit combinations tested. Only the42 combination exhibited a depression of the maximum effect at concentrations higher than 20µM nicotine.5. After a single nicotine pulse, receptor desensitization (calculated as a single exponential decay) was significantly slower for42 than for either32 or22.6. Concentrations of nicotine that attained a near maximum effect were applied, washed, and re-applied in four minute cycles. The responses were calculated as percentages of the current evoked by the initial application. Following 16 minutes of this protocol, the42 combination showed a greater reduction of the original response as compared to the22 and32 subunit combinations. Taking points 5 and 6 together, these experiments suggest that the42 receptor subtype desensitizes at a slower rate and remains longer in the desensitized state.7. Because42 is the main receptor subunit combination within the brain and is up-regulated by nicotine, our data may be important for understanding the molecular basis of tolerance to this drug.     

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.     

TNF alpha is required for hypoxia-mediated right ventricular hypertrophy

Hypoxia has been shown to activate the pleiotropic cytokine TNF in the lung. TNF in turn, is known to induce pulmonary vasoconstriction. Additional effects of this cytokine in hypoxia mediated cardiopulmonary remodeling are poorly understood. To further evaluate the role of TNF in chronic hypoxia we exposed TNF null (TNF–/–) and wild-type mice to three weeks of hypobaric hypoxia (10% O₂). Equivalent erythocytosis (Hematocrit increased by 40%) developed in both genetic backgrounds. In contrast, right ventricular systolic pressure increased in response to three weeks of hypoxia in the wild-type mice ( 75%), yet was unaltered in the TNF–/– mice. Concomitantly right ventricular hypertrophy was attenuated in the TNF–/– mice (35 ± 5% increase) when compared to wild-type mice (124 ± 6% increase p < 0.001, n 20). Interestingly in both strains the lung wet weights increased to a similar degree in response to hypoxia. In conclusion, our data demonstrate that TNF is an integral autocoid in chronic hypoxia mediated right ventricular hypertrophy. Moreover, additional components of cardiopulmonary remodeling may be regulated by TNF signaling as suggested by the negligible right ventricular systolic pressure response to hypoxia in the absence of TNF.