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Dive into the research topics where Hubert Bartosz-Bechowski is active.

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Featured researches published by Hubert Bartosz-Bechowski.


Dalton Transactions | 2006

Chemistry of palladium phosphinite (PPh2(OR)) and phosphonite (P(OPh)2(OH)) complexes: catalytic activity in methoxycarbonylation and Heck coupling reactions

Iweta Pryjomska; Hubert Bartosz-Bechowski; Zbigniew Ciunik; Anna M. Trzeciak; Józef J. Ziółkowski

The new phosphinite and phosphonite complexes (1-8) are very efficient catalysts for the methoxycarbonylation of iodobenzene and Heck cross-coupling of bromobenzene with butyl acrylate. High catalytic activity of these complexes can be explained by their in situ transformations during the reaction, stimulated by the presence of water, acid (HCl) or base (NEt(3)). Hydrolysis of phosphinite palladium complexes of the form trans-PdCl(2)[PPh(2)(OR)](2) (R = C(6)F(5), 2, (t)Bu 3, or O-menthyl 4) results in the formation of the dimeric complex [mu-ClPd(PPh(2)OH)(PPh(2)O)](2) 5, which is deprotonated by NEt(3), producing a polymeric complex of formula [Pd(P(O)PPh(2))(2)](n) 8. The reverse reaction, protonolysis of 8 with HCl, leads back to 5 and the monomeric complex 5a. The phosphinite complex PdCl(2)[PPh(2)(OBu)](2)1 with a more lipophilic ligand, PPh(2)(OBu), does not undergo hydrolysis under the same conditions. In the reaction of PdCl(2)(cod) with P(OPh)(2)(OH), the new dimer [mu-ClPd(P(OPh)(2)OH)(P(OPh)(2)O)](2) 6 was obtained, whereas reaction of Pd(OAc)(2) with P(OPh)(2)(OH) leads to the polymeric complex [Pd[P(O)(OPh)(2)](2)](n) 7. Protonolysis of 7 with HCl results in the formation of 6.


Molecular Immunology | 1992

Analysis of peptidic epitopes recognized by the three monoclonal antibodies specific for the same region of glycophorin a but showing different properties

Kazimiera Waśniowska; Maria Duk; Marcin Czerwinski; Iga Steuden; Danuta Duś; Radzikowski C; Hubert Bartosz-Bechowski; Danuta Konopińska; Elwira Lisowska

Analysis of epitopes for the three monoclonal antibodies (GPA105, GPA33, OSK4-1) against glycophorin A (GPA) was performed with the use of proteolytic fragments of GPA, the synthetic nonapeptide with the sequence of amino acid residues 35-43 of GPA, and a series of peptides synthesized on plastic pins. The antibodies were specific for a short peptide sequence RAHE (a.a. 39-42 of GPA, MAbs GPA105 and OSK4-1) or RAHEV (a.a. 39-43 of GPA, MAb GPA33). Despite recognizing the same fragment of GPA, the three antibodies showed differences in fine specificity and in response to antigen desialylation. Reactions with single replacement analogs of the RAHEV sequence showed that immunodominant (unreplaceable) residues for the MAbs GPA33 and OSK4-1 were His and Glu, respectively, whereas no such residue was found for the MAb GPA105. Desialylation of the antigen gave strong enhancement of reactivity with the MAb GPA33, moderate--with the MAb GPA105, and weak or no enhancement of reaction with the MAb OSK4-1. The results showed that monoclonal antibodies directed against the same fragment of the polypeptide chain of densely glycosylated antigen may recognize different subsites which are masked at different degree by sialic acid residues.


Peptides | 1998

Biological Activity of Structural Analogs and Effect of Oil as a Carrier of Trypsin Modulating Oostatic Factor of the Gray Fleshfly Neobellieria bullata

Ine Janssen; Jan Koolman; Danuta Konopińska; Hubert Bartosz-Bechowski; Liliane Schoofs; Arnold De Loof

The trypsin modulating oostatic factor from the gray fleshfly Neobellieria bullata (Neb-TMOF) is released from the ovary at the end of vitellogenesis and inhibits trypsin biosynthesis in the midgut. This inhibition indirectly results in an arrest of oocyte growth. Additional experiments with N. bullata were performed to characterize its trypsin modulating and oostatic properties in more detail. After suspending the peptide in wheat germ oil, the threshold dose for oostatic activity was lowered one thousand times (2.10(-5) in oil versus 2.10(-2) pmoles per fly in Ringer). By use of the Neobellieria trypsin biosynthesis assay, 17 analogs of the hexapeptide were tested for inhibitory activity. The following structural elements were demonstrated to be critical for biological activity: the alcohol function at position 3 (Thr residue); a positively charged basic group at the C terminus (His residue); and the Asn side chain at positions 1 and 4.


Amino Acids | 2009

Solid phase synthesis of peptides containing novel amino acids, substituted 3-benzimidazolealanines

Małgorzata Koprowska-Ratajska; Alicja Kluczyk; Piotr Stefanowicz; Hubert Bartosz-Bechowski; Zbigniew Szewczuk

A direct solid-phase synthesis of a series of substituted benzimidazole-containing peptides is described. The method involves on-resin formation of new amino acids containing benzimidazole derivatives in the side chain. The heterocycle conjugates were obtained by reaction between aldehydes and peptides containing β-(3,4-diaminophenyl)alanine residue, immobilized on a polymeric solid support.


Letters in Peptide Science | 1998

Insect Trypsin Modulating Oostatic Factor (Neb-TMOF) and Its Analogs: Preliminary Structure/Biological Function Relationship Studies

Danuta Konopińska; Hubert Bartosz-Bechowski; Mariola Kuczer; Grzegorz Rosiński; Ine Janssen; Arnold De Loof

Neb-TMOF, the trypsin modulating oostatic factor of gray fleshflyNeobellieria bullata, is a hexapeptide with the following sequence: H-Asn-Pro-Thr-Asn-Leu-His-OH. It has been isolated from vitellogenic ovaries in 1994. TMOF, the newly discovered insect peptide, inhibits trypsin biosynthesis in the gut, lowers yolk polypeptide concentration in the hemolymph and strongly inhibits ecdysone biosynthesis by larval ring glands. It is interesting that this short non-protected peptide contains in its molecule two Asn residues at positions 1 and 4 and His at its C-terminus. To obtain information about the role of the His-6 and Asn-4 residues we synthesised two series of Neb-TMOF analogs, modified: (1) in position 6 byd-His (I), His(Bzl) (II) and Phe(p-X) derivatives, where X=NH2 (III), NO2 (IV), OEt (V) and OH (VI) and (2) in position 4 by such amino acid residues as Ser (VII), Thr (VIII), Gly (IX), Asp (X), Glu (XI) andd-Asn (XII). The influence of these peptides on trypsin biosynthesis inN. bullata was determinedin vivo. In preliminary investigations, we found that Neb-TMOF, [Phe(NH2)6], and [Phe(NO2)6]-Neb-TMOF inhibited trypsin biosynthesis, whereas [d-His)6]- and [d-His(Bzl)6]-Neb-TMOF were inactive. In further biological studies performedin vitro on heart ofTenebrio molitor were found that-TMOF and [Phe(p-NH2)6]-Neb-TMOF showed weak cardioexcitatory activity, about 30% of the cardioexcitatory activity of proctolin, an insect neuromodulating peptide.


Central European Journal of Chemistry | 2010

Hydrate of 2,3:4,5-di-O-isopropylidene-β-D-arabino-hexos-2-ulo-2,6-pyranose as new crystalline reagent in the preparation of Amadori derived peptides

Piotr Stefanowicz; Joanna Batorska; Monika Kijewska; Hubert Bartosz-Bechowski; Zbigniew Szewczuk; Tadeusz Lis

We established, that crystalline hydrate of 2,3:4,5-di-O-isopropylidene-β-D-arabino-hexos-2-ulo-2,6-pyranose is a new, convenient and stable reagent for solid phase synthesis of peptide derived Amadori products. The structure of the title compound was studied by X-ray analysis, NMR spectroscopy, and high resolution ESI-MS. The crystal structure indicated the existence of two symmetry-independent molecules that were not connected with hydrogen bonds. A comparison with previously reported 2,3:4,5-di-O-isopropylidene-β-D-fructopyranose revealed, that these two compounds are isostructural.


Journal of Applied Entomology | 1991

Further search of deterrent properties for stored product insects among some amino acid and peptide derivatives

J. Nawrot; Danuta Konopińska; Wieslaw Sobótka; Hubert Bartosz-Bechowski

Among 27 amino acid derivatives, comprising simple amino acids, amino acids with pyrethroidal moiety, dipeptides and several modified insect neuropeptide proctolin analogues, 1 compound revealed high activity and 21 compounds had good antifeeding activity against selected stored product insect pests. The bioassays were carried out in the wafer disc test by the inhibition of feeding in the beetles Sitophilus granarius and Tribolium confusion as well as in larvae of T. confusum and Trogoderma granarium.


Canadian Journal of Chemistry | 2001

Structural studies of PdCl2L2 complexes with fluorinated phosphines, phosphites, and phosphinites as precursors of benzyl bromide carbonylation catalysts, and and X-ray crystal structure of cis-PdCl2[PPh2(OEt)]2

Anna M. Trzeciak; Hubert Bartosz-Bechowski; Zbigniew Ciunik; Katarzyna Niesyty; Józef J. Ziółkowski


International Journal of Peptide and Protein Research | 2009

New N-terminal modified proctolin analogues: synthesis and their cardioexcitatory effect on insects

Danuta Konopińska; Grzegorz Rosiński; Andrzej Lesicki; Przemysław Sujak; Wiesław Sobótka; Hubert Bartosz-Bechowski


International Journal of Peptide and Protein Research | 2009

Further studies on proctolin analogues modified in position 2 of the peptide chain and their influence on heart-beat frequency of insects.

Hubert Bartosz-Bechowski; Grzegorz Rosiński; Danuta Konopińska; Prezemysław Sujak; Wieslaw Sobótka

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Grzegorz Rosiński

Adam Mickiewicz University in Poznań

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Wieslaw Sobótka

Polish Academy of Sciences

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Ine Janssen

Katholieke Universiteit Leuven

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