Wyniki wyszukiwania

1

Genetyczna kontrola symbiozy Rhizobium z roślinami motylkowatymi

100%

Skorupska A.

Postępy Mikrobiologii

|

1988

|

tom 27

|

nr 1-2

2

Mass spectrometry identification of membrane-bound respiratory nitrate reductase from Bradyrhizobium sp. [Lupinus]

72%

Polcyn W.

Acta Biochimica Polonica

|

2008

|

tom 55

|

nr 4

753-760

Respiratory nitrate reductase (NR) from Bradyrhizobium sp. (Lupinus) USDA 3045 has biochemical properties of the membrane-bound NR type. However, in the completely sequenced rhizobium genomes only genes for the periplasmic type of dissimilatory NR were found. Therefore purification and identification of the enzyme by tandem mass spectrometry (MS/MS) was under taken. MS/MS spectra representing 149 unique tryptic peptides derived from purified 137-kDa subunit matched the NCBInr-deposited NarG sequences. MS/MS sequencing of two other SDS/PAGE bands (65- and 59-kDa) identified them as derivatives of the NarH-type protein. Applying additional validation criteria, 73% of the sequence of the NarG subunit (902 aa) and 52% of NarH sequence (266 aa) was assembled (UniProt KB acc. no. P85097 and P85098). This is the first unambiguous identification of an active NarGH-like NR in rhizobia. Moreover, arguments are provided here for the existence of a functional enzyme of this type also among other rhizobial species, basing on immunoblot screening and the presence of membrane-associated NR-active electrophoretic forms.

3

Nod genes and Nod signals and the evolution of the rhizobium legume symbiosis

72%

Debelle F., Moulin L., Mangin B., Denarie J., Boivin C.

Acta Biochimica Polonica

|

2001

|

tom 48

|

nr 2

The establishment of the nitrogen-fixing symbiosis between rhizobia and legumes re quires an ex change of sig nals be tween the two part ners. In re sponse to flavonoids ex creted by the host plant, rhizobia syn the size Nod fac tors (NFs) which elicit, at very low con cen tra tions and in a spe cific man ner, var i ous sym bi otic re sponses on the roots of the le gume hosts. NFs from sev eral rhizobial spe cies have been char ac ter ized. They all are lipo-chitooligosaccharides, con sist ing of a back bone of gen er ally four or five glucosamine residues N-acylated at the non-reducing end, and carrying various O-substituents. The N-acyl chain and the other substituents are important determi nants of the rhizobial host spec i fic ity. A num ber of nodulation genes which spec ify the syn the sis of NFs have been iden ti fied. All rhizobia, in spite of their di ver sity, pos sess conserved nodABC genes responsible for the synthesis of the N-acylated oligosaccharide core of NFs, which sug gests that these genes are of a monophyletic or i gin. Other genes, the host spe cificnod genes, spec ify the sub sti tu tions of NFs. The cen tral role of NFs and nod genes in the Rhizo bium-legume sym bi o sis sug gests that these factors could be used as mo lec u lar mark ers to study the evo lu tion of this sym bi o sis. We have stud ied a num ber of NFs which are N-acylated by α,β-unsaturated fatty acids. We found that the abil ity to syn the size such NFs does not cor re late with tax o- nomic po si tion of the rhizobia. How ever, all rhizobia that pro duce NFs such nodulate plants be long ing to re lated tribes of le gumes, the Trifolieae, Vicieae, and Galegeae, all of them be ing mem bers of the so-called galegoid group. This sug gests that the abil ity to recognize the NFs with α,β-unsaturated fatty acids is limited to this group of legumes, and thus might have ap peared only once in the course of le gume evo lu tion, in the galegoid phy lum.

4

Use of potato extract broth for culturing root-nodule bacteria

58%

Martyniuk S., Oron J.

Polish Journal of Microbiology

|

2011

|

tom 60

|

nr 4

Liquid media containing potato extract and 1% of glucose or sucrose were used to culture root-nodule bacteria (rhizobia) in shaken Erlenmeyer flasks. For comparison, these bacteria were also cultured in yeast extract-mannitol broth (YEMB) as a standard medium. Proliferation of rhizobia was monitored by measuring optical densities (OD₅₅₀) of the cultures and by plate counting of the viable cells (c.f.u) of the bacteria. In general, multiplication of the rhizobia in potato extract-glucose broth (PEGB) and potato extract-sucrose broth (PESB) was markedly faster, as indicated by higher values of OD₅₅₀, than in YEMB. The numbers of R. leguminosarum bv. vicae GGL and S.meliloti 330 in PEGB and PEGB were high and ranged from 1.2×10¹⁰ to 4.9×10¹⁰ mL⁻¹ after 48 h of incubation at 28°C. B. japonicum B3S culture in PEGB contained 6.4×10⁹ c.f.u. ml⁻¹ after 72 h of incubation. PEGB and YEMB cultures of the rhizobia were similar with respect to their beneficial effects on nodulation of the host-plants of these bacteria.

5

Competitiveness of Rhizobium leguminosarum bv. trifolii strains in mixed inoculation of clover (Trifolium pratense)

58%

Wielbo J., Marek-Kozaczuk M., Kidaj D., Skorupska A.

Polish Journal of Microbiology

|

2011

|

tom 60

|

nr 1

Rhizobium leguminosarum bv. trifolii (Rlt) establishes beneficial root nodule symbiosis with clover. Twenty Rlt strains differentially marked with antibiotic-resistance markers were investigated in terms of their competitiveness and plant growth promotion in mixed inoculation of clover in laboratory experiments. The results showed that the studied strains essentially differed in competition ability. These differences seem not to be dependent on bacterial multiplication in the vicinity of roots, but rather on complex physiological traits that affect competitiveness. The most remarkable result of this study is that almost half of the total number of the sampled nodules was colonized by more than one strain. The data suggest that multi-strain model of nodule colonization is common in Rhizobium-legume symbiosis and reflects the diversity of rhizobial population living in the rhizosphere.

6

Reduction of bacterial genome size and expansion resulting from obligate intracellular life style and adaptation to soil habitat

58%

Stepkowski T., Legocki A. B.

Acta Biochimica Polonica

|

2001

|

tom 48

|

nr 2

Prokaryotic or gan isms are ex posed in the course of evo lu tion to var i ous im pacts, result ing of ten in dras tic changes of their ge nome size. De pending on cir cum stances, the same lin eage may di verge into spe cies hav ing sub stan tially re duced genomes, or such whose genomes have un der gone con sid er able en large ment. Ge nome re duc tion is a con se quence of ob li gate intracellular life style ren der ing nu mer ous genes ex pend able. An other con se quence of intracellular life style is re duc tion of ef fec tive pop u la- tion size and lim ited pos si bil ity of gene ac quire mentvia lat eral trans fer. This causes a state of re laxed se lec tion re sult ing in ac cu mu la tion of mildly del e te ri ous mu ta tions that can not be cor rected by re com bi na tion with the wild type copy. Thus, gene loss is usually irreversible. Additionally, constant environment of the eukaryotic cell renders that some bac te rial genes in volved in DNA re pair are ex pand able. The loss of these genes is a prob a ble cause of mutational bias re sult ing in a high A+T con tent. While causes of genome reduction are rather indisputable, those resulting in genome ex pan sion seem to be less ob vi ous. Pre sum ably, the ge nome en large ment is an indirect consequence of adaptation to changing environmental conditions and requires the ac qui si tion and in te gra tion of nu mer ous genes. It seems that the need for a great number of capabilities is common among soil bacteria irrespective of their phylo gen etic re la tion ship. How ever, this would not be pos si ble if soil bac te ria lacked in dig e nous abil i ties to ex change and ac cu mu late ge netic in for ma tion. The lat ter are con sid er ably fa cil i tated when house keep ing genes are phys i cally sep a rated from adaptive loci which are useful only in certain circum stances.

Ograniczanie wyników

3 Acta Biochimica Polonica

2 Polish Journal of Microbiology

1 Postępy Mikrobiologii

2 Skorupska A.

1 Boivin C.

1 Debelle F.

1 Denarie J.

1 Kidaj D.

1 Legocki A. B.

1 Mangin B.

1 Marek-Kozaczuk M.

1 Martyniuk S.

1 Moulin L.

1 Oron J.

1 Polcyn W.

1 Stepkowski T.

1 Wielbo J.

2 2011

1 2008

2 2001

1 1988

Genetyczna kontrola symbiozy Rhizobium z roślinami motylkowatymi

Mass spectrometry identification of membrane-bound respiratory nitrate reductase from Bradyrhizobium sp. [Lupinus]

Nod genes and Nod signals and the evolution of the rhizobium legume symbiosis

Use of potato extract broth for culturing root-nodule bacteria

Competitiveness of Rhizobium leguminosarum bv. trifolii strains in mixed inoculation of clover (Trifolium pratense)

Reduction of bacterial genome size and expansion resulting from obligate intracellular life style and adaptation to soil habitat