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G Backes

Publications and source records attributed to G Backes.

15 recordsLinked to original sources
PubMed2005

QTLs for straw quality characteristics identified in recombinant inbred lines of a Hordeum vulgare x H. spontaneum cross in a Mediterranean environment.

Barley straw is commonly used as animal feed in many developing countries. Even a small increase in its nutritive value can have a large impact on animal production, and hence, on rural livelihood and human nutrition. Straw quality is strongly affected by environmental factors and is, therefore, difficult to improve with empirical breeding. The objective of this study was to identify molecular markers to facilitate the improvement of straw quality in barley. For this purpose, we have used the genetic linkage map that was already developed for recombinant inbred lines (RILs) of the cross between a Hordeum vulgare cultivar ('Arta') and a H. spontaneum line (H. spontaneum 41-1), covering a total of 890 cM. Straw parameters from RILs grown at Tel Hadya and Breda (ICARDA's research stations) in 2 years (1996/1997 and 1997/1998) were analyzed by NIRS for predicted nutritional characteristics including neutral detergent fiber, acid detergent fiber, lignin, digestible organic matter in dry matter, voluntary intake, crude protein, and straw morphology (the percentage of blades, sheaths, and stems). Localization of QTLs was performed using Windows QTL Cartographer, version 2.0. Seventy-three QTLs were identified, the majority of which (17) in the driest of the four environments. Only six QTLs were identified in two environments; in five cases, one of the two was the wettest environment. This is discussed in relation to the possibility of improving straw quality in favorable environments where yields are higher, rather than in dry environments where straw quality is already relatively good.

Animal Feed↗
PubMed2005

Response to lysine in a wheat gluten diet in adult minipigs after short-and long-term dietary adaptation as assessed with an indicator amino acid oxidation and balance technique.

An experiment was conducted to examine the response to wheat gluten (WG)-based diets at two lysine levels in adult minipigs (23 kg BW) using the indicator AA oxidation (IAAO) approach and N balance. Twenty minipigs (n = five per group), fitted with reentrant ileoileal cannulas allowing collection of ileal effluents, were fed restrictively two WG-based diets (WG and WG + Lys; 2.7 and 6.6 g of lysine/kg, respectively) for adaptation periods of 10 and 100 d. On d 7 and 9, for pigs fed the diets for 10 d, and on d 97 and 99, for pigs fed the diets for 100 d, primed i.v. fasted/fed tracer protocols with [(13)C]bicarbonate, and [(13)C]leucine were performed. With the WG diet, [(13)C]bicarbonate recoveries (%) were lower irrespective of the adaptation period, and higher during the fed period (fasted: WG + Lys = 82.5, and WG = 69.1; fed: WG + Lys = 90.6, and WG = 85.9; P < 0.05). Leucine oxidation rate was higher with the lower lysine intake (WG = 194.6 vs. 109.5 mg/[kg BW x d]; P < 0.05). Wheat gluten feeding resulted in a negative leucine balance independent of the adaptation period (WG = -29.1, and WG + Lys = 48.2 mg/[kg BW x d]; P < 0.05). In contrast with the IAAO method, N balance did not differ between the two lysine intakes, possibly because of an underestimation of N losses. The finding of a lower (13)C bicarbonate recovery with the lower dietary lysine intake suggests that caution should be taken in using a single recovery factor for all AA oxidation studies.

Animals↗
PubMed2003

QTLs for agronomic traits in the Mediterranean environment identified in recombinant inbred lines of the cross 'Arta' x H. spontaneum 41-1.

A genetic linkage map has been developed for recombinant inbred lines (RILs) of the cross 'Arta' x Hordeum spontaneum 41-1. One hundred and ninety four RILs, randomly chosen from a population of 494 RILs, were mapped with 189 markers including one morphological trait ( btr = brittle rachis locus). The linkage map extended to 890 cM. Agronomic traits such as grain yield, biological yield, days to heading, plant height, cold tolerance and others were evaluated at the ICARDA research stations Tel Hadya and Breda during the years 1996-97 and 1997-98. QTLs for agronomic traits related to drought resistance were localized. For the most-important character 'plant height under drought stress', QTLs on 2H, 3H and 7H were detected. The 'plant height' QTLs, specially the one on 3H, showed pleiotropic effects on traits such as days to heading, grain yield and biological yield. QTLs were also identified for other traits associated with adaptation to the Mediterranean environment such as cold tolerance, days to heading and tiller number. The identification of QTLs for agronomic traits is a first step to analyze and to dissect complex characters such as adaptation to drought tolerance.

Adaptation, Physiological↗
PubMed2003

Barley disease resistance gene analogs of the NBS-LRR class: identification and mapping.

The majority of verified plant disease resistance genes isolated to date are of the NBS-LRR class, encoding proteins with a predicted nucleotide binding site (NBS) and a leucine-rich repeat (LRR) region. We took advantage of the sequence conservation in the NBS motif to clone, by PCR, gene fragments from barley representing putative disease resistance genes of this class. Over 30 different resistance gene analogs (RGAs) were isolated from the barley cultivar Regatta. These were grouped into 13 classes based on DNA sequence similarity. Actively transcribed genes were identified from all classes but one, and cDNA clones were isolated to derive the complete NBS-LRR protein sequences. Some of the NBS-LRR genes exhibited variation with respect to whether and where particular introns were spliced, as well as frequent premature polyadenylation. DNA sequences related to the majority of the barley RGAs were identified in the recently expanded public rice genomic sequence database, indicating that the rice sequence can be used to extract a large proportion of the RGAs from barley and other cereals. Using a combination of RFLP and PCR marker techniques, representatives of all barley RGA gene classes were mapped in the barley genome, to all chromosomes except 4H. A number of the RGA loci map in the vicinity of known disease resistance loci, and the association between RGA S-120 and the nematode resistance locus Ha2 on chromosome 2H was further tested by co-segregation analysis. Most of the RGA sequences reported here have not been described previously, and represent a useful resource as candidates or molecular markers for disease resistance genes in barley and other cereals.

Amino Acid Sequence↗
PubMed2002

Localisation of genes for resistance against Blumeria graminis f.sp. hordei and Puccinia graminis in a cross between a barley cultivar and a wild barley (Hordeum vulgare ssp. spontaneum) line.

The aims of this investigation have been to map new (quantitative) resistance genes against powdery mildew, caused by Blumeria graminis f.sp. hordei L., and leaf rust, caused by Puccinia hordei L., in a cross between the barley ( Hordeum vulgare ssp. vulgare) cultivar "Vada" and the wild barley ( Hordeum vulgare ssp. spontaneum) line "1B-87" originating from Israel. The population consisted of 121 recombinant inbred lines. Resistance against leaf rust and powdery mildew was tested on detached leaves. The leaf rust isolate "I-80" and the powdery mildew isolate "Va-4", respectively, were used for the infection in this experiment. Moreover, powdery mildew disease severity was observed in the field at two different epidemic stages. In addition to other DNA markers, the map included 13 RGA (resistance gene analog) loci. The structure of the data demanded a non-parametric QTL-analysis. For each of the four observations, two QTLs with very high significance were localised. QTLs for resistance against powdery mildew were detected on chromosome 1H, 2H, 3H, 4H and 7H. QTLs for resistance against leaf rust were localised on 2H and 6H. Only one QTL was common for two of the powdery mildew related traits. Three of the seven QTLs were localised at the positions of the RGA-loci. Three of the five powdery mildew related QTLs are sharing their chromosomal position with known qualitative resistance genes. All detected QTLs behaved additively. Possible sources of the distorted segregation observed, the differences between the results for the different powdery mildew related traits and the relation between qualitative and quantitative resistance are discussed.

Ascomycota↗
PubMed2000

New York State pharmacists' attitudes toward needle and syringe sales to injection drug users before implementation of syringe deregulation.

In May 2000, New York State passed legislation permitting the sale, purchase, and possession of up to 10 needles and syringes without a prescription. The law is intended to reduce the transmission of human immunodeficiency virus (HIV) and hepatitis among injection drug users (IDUs), their sexual partners, and their children. To obtain baseline information about the attitudes and likely practices of New York State pharmacists, we distributed a self-administered questionnaire to attendees of the state pharmacy association meeting in June 2000. Of 48 usable responses, 19% were from New York City and the rest from New York State. Of the 48, 42% were unaware of the new law before the day of the survey, and 60% were somewhat or very willing to sell needles and syringes to an IDU. Of those who were not willing to sell to an IDU, 82% cited familiarity of the customer as a very important consideration in their decision making. Those who were not willing to sell to an IDU were more concerned about the detrimental impact of syringe sales on the community, were less likely to be aware of the new law, and were more likely to be concerned about legal liability for syringe sales. Over 80% of all pharmacists believed that syringe sales to IDUs are an important preventive health measure. The majority also favored learning more about the law. Compared to other state surveys of pharmacists, these preliminary data show a similar level of interest in becoming involved with syringe availability programs.

Attitude of Health Personnel↗
PubMed1995

Evidence for a methylammonium-binding site on methylamine dehydrogenase of Thiobacillus versutus.

The nonconvertible substrate analogues di-, tri-, and tetramethylammonium are bound with fairly high affinity to oxidized methylamine dehydrogenase (MADHox) from Thiobacillus versutus and induce the same red-shift in the optical absorbance spectrum of MADHox as do the monovalent cations Cs+, Rb+, and NH4+. Like the monovalent cations, trimethylamine also competitively inhibits the reduction of MADHox by methylamine. Rapid-scan experiments show that within the first few milliseconds of the reaction between MADHox and methylamine a red-shifted intermediate is formed as well. Taken together these experiments demonstrate the existence of a common binding site on MADHox for the substrate CH3NH3+, the substrate analogues (CH3)2NH2+, (CH3)3NH+, and (CH3)4N+, and the monovalent cations Cs+, Rb+, and NH4+. Therefore we conclude that, prior to conversion, methylamine is noncovalently bound to MADHox as a cation. The resonance Raman spectra of MADHox in the absence and presence of Cs+, NH4+, and (CH3)3NH+ are very similar, except for the C=O stretching frequencies of the o-quinone carbonyls of the tryptophyltryptophanquinone (TTQ) active center, which show 5-30 cm-1 downshifts. From these Raman results and the X-ray crystal structure, we conclude that the CH3NH3+ binding site is in close proximity to the O6 carbonyl oxygen of the TTQ.

Binding Sites↗
PubMed1991

Characterization of the tryptophan-derived quinone cofactor of methylamine dehydrogenase by resonance Raman spectroscopy.

The resonance Raman (RR) spectrum of oxidized methylamine dehydrogenase (MADHOX) exhibits a set of C-H, C-C, C = C, and C = O vibrational modes between 900 and 1700 cm-1 that are characteristic of the quinone moiety of the tryptophan tryptophlyquinone (TTQ) cofactor. The close similarity of the RR spectra for MADHs from Paracoccus denitrificans (Pd), Thiobacillus versutus (Tv), and bacterium W3A1 proves that the same cofactor is present in all three proteins. The MADHs from Pd and Tv have a v(C = O) mode at approximately 1625 cm-1 that shifts approximately 20 cm-1 upon 18O substitution of one of the carbonyl oxygens and is assigned to the in-phase symmetric stretch of the two C = O groups. The semiquinone form of Pd MADH has its own characteristic RR spectrum with altered peak frequencies and intensities as well as a decrease in the total number of peaks. The hydroxide and ammonia adducts of MADHOX produce RR spectra similar to that of the semiquinone. The spectral changes in all three cases are interpreted as being due to reduced conjugation of the cofactor. The ammonia adduct is formulated as a carbinolamine, a likely intermediate in the enzymatic mechanism. In contrast, formation of the electron-transfer complex between amicyanin and MADHOX has no effect on the vibrational frequencies (and, hence, structure) of either the MADH quinone or the amicyanin blue copper site. The behavior of the TTQ cofactors of Pd and Tv MADHs are very similar to one another and somewhat different from W3A1 MADH, particularly with regard to adduct formation and ability to undergo isotope exchange with solvent. These differences are ascribed to the cofactor environments within the proteins rather than to the structure of the cofactor itself.

Ammonia↗
PubMed1990

Activation of the iron-containing B2 protein of ribonucleotide reductase by hydrogen peroxide.

The active form of protein B2, the small subunit of ribonucleotide reductase, contains two dinuclear Fe(III) centers and a tyrosyl radical. The inactive metB2 form also contains the same diferric complexes but lacks the tyrosyl radical. We now demonstrate that incubation of metB2 with hydrogen peroxide generates the tyrosyl radical. The reaction is optimal at 5.5 nM hydrogen peroxide, with a maximum of 25-30% tyrosyl radical being formed after approximately 1.5 hr of incubation. The activation reaction is counteracted by a hydrogen peroxide-dependent reduction of the tyrosyl radical. It is likely that the generation of the radical proceeds via a ferryl intermediate, as in the proposed mechanisms for cytochrome P-450 and the peroxidases.

Enzyme Activation↗
PubMed1989

Resonance Raman spectroscopy of ribonucleotide reductase. Evidence for a deprotonated tyrosyl radical and photochemistry of the binuclear iron center.

Native ribonucleotide reductase from Escherichia coli exhibits a resonance-enhanced Raman mode at 1498 cm-1 that is characteristic of a tyrosyl radical. The Raman frequency as well as the absorption maximum at 410 nm identifies the radical as being in a deprotonated state. The B2 subunit of ribonucleotide reductase shows an additional resonance Raman mode at 493 cm-1 that has been assigned to the symmetric stretch of an Fe-O-Fe moiety. When samples of active B2 or metB2 are exposed to a tightly focused laser beam at 406.7 nm, there is a loss of intensity at 493 cm-1 and the appearance of a new peak at 595 cm-1. Although the 595-cm-1 feature was previously assigned to an Fe-OH vibration on the basis of its 23-cm-1 shift to lower energy in H2(18)O and the apparent dependence of its intensity on pH [Sjöberg, B. M., Loehr, T. M., & Sanders-Loehr, J. (1987) Biochemistry 26, 4242], the present studies indicate that the intensity of this mode is dependent primarily on input laser power. The peak at 595 cm-1 is more plausibly assigned to a new vs(Fe-O-Fe) mode in view of its lack of the deuterium isotope dependence expected for an Fe-OH mode and its resonant scattering cross section which is comparable to that of the 493-cm-1 mode. This new species has a calculated Fe-O-Fe angle of approximately 113 degrees compared to approximately 138 degrees calculated for the Fe-O-Fe unit in unmodified protein B2. One possible explanation for the photoinduced vibrational mode is that a bridging solvent molecule has been inserted in place of a bridging carboxylate.

Escherichia coli↗
PubMedDate not supplied

[Group relations outside the family of elderly females--some theses and reflections exemplified by 3 groups].

This article deals with the importance of non-familial group relations for older women. Regarding the background of the specific old age problems of women and their life-long development, it demonstrates the specific function of participation in non-familial groups for older women. These groups give the older women important support in overcoming the problems of old age, with, for instance, female discussion groups, and voluntary groups, and initiatives of older people. These three groups can be seen as a tool to solve the problems of aging. However, the number and quality of these groups is not sufficient in regard to the older women, particularly the underprivileged. For this reason we conclude by mailing proposals for the promotion and enlargement of these groups and the elimination of the barriers hindering the participation of older women.

Aged↗