Highly hydrolytic reuteransucrase from probiotic Lactobacillus reuteri strain ATCC 55730

Lactobacillus reuteri strain ATCC 55730 (LB BIO) was isolated as a pure culture from a Reuteri tablet purchased from the BioGaia company. This probiotic strain produces a soluble glucan (reuteran), in which the majority of the linkages are of the α-(1→4) glucosidic type (∼70%). This reuteran also contains α-(1→6)- linked glucosyl units and 4,6-disubstituted α-glucosyl units at the branching points. The LB BIO glucansucrase gene (gtfO) was cloned and expressed in Escherichia coli, and the GTFO enzyme was purified. The recombinant GTFO enzyme and the LB BIO culture supernatants synthesized identical glucan polymers with respect to linkage type and size distribution. GTFO thus is a reuteransucrase, responsible for synthesis of this reuteran polymer in LB BIO. The preference of GTFO for synthesizing α-(1→4) linkages is also evident from the oligosaccharides produced from sucrose with different acceptor substrates, e.g., isopanose from isomaltose. GTFO has a relatively high hydrolysis/transferase activity ratio. Complete conversion of 100 mM sucrose by GTFO nevertheless yielded large amounts of reuteran, although more than 50% of sucrose was converted into glucose. This is only the second example of the isolation and characterization of a reuteransucrase and its reuteran product, both found in different L. reuteri strains. GTFO synthesizes a reuteran with the highest amount of α-(1→4) linkages reported to date

Structural characterization of linear isomalto-/malto-oligomer products synthesized by the novel GTFB 4,6-α-glucanotransferase enzyme from Lactobacillus reuteri 121

Recently, a novel glucansucrase (GS)-like gene (gtfB) was isolated from the probiotic bacterium Lactobacillus reuteri 121 and expressed in Escherichia coli. The purified recombinant GTFB enzyme was characterized and turned out to be inactive with sucrose, the natural GS substrate. Instead, GTFB acted on malto-oligosaccharides (MOSs), thereby yielding elongated gluco-oligomers/polymers containing besides (α1→4) also (α1→6) glycosidic linkages, and it was classified as a 4,6-α-glucanotransferase. To gain more insight into its reaction specificity, incubations of the GTFB enzyme with a series of MOSs and their corresponding alditols [degree of polymerization, DP2(-ol)–DP7 (-ol)] were carried out, and (purified) products were structurally analyzed with matrix-assisted laser desorption ionization time-of-flight mass spectrometry and one-/two-dimensional 1H and 13C nuclear magnetic resonance spectroscopy. With each of the tested malto-oligomers, the GTFB enzyme yielded series of novel linear isomalto-/malto-oligomers, in the case of DP7 up to DP >35.

Laparoscopic subtotal hysterectomy versus laparoscopic total hysterectomy: a decade of experience

At present, there are only few data on the surgical outcomes of laparoscopic hysterectomy (LH). Up till now, it has been unclear whether there is a difference in number of complications among the subcategories of laparoscopic total hysterectomy and laparoscopic subtotal hysterectomy (LSH). Therefore, we have performed a retrospective analysis to evaluate the peri- and postoperative outcomes in women undergoing LSH versus LH. This multi-centre retrospective cohort study (Canadian Task Force classification II-2) was conducted in multi-centres (two teaching hospitals and one university medical centre) in the Netherlands, all experienced in minimally invasive gynaecology. In a multi-centre retrospective cohort study we compared the long-term outcomes of laparoscopic subtotal hysterectomy and laparoscopic total hysterectomy (including laparoscopic assisted vaginal hysterectomy, laparoscopic hysterectomy and total laparoscopic hysterectomy). All laparoscopic hysterectomies from the last 10 years (January 1998 till December 2007) were included. Patient characteristics, intra- and postoperative complications, operating time and duration of hospital stay were recorded. The minimum follow-up was 6 months. A total of 390 cases of laparoscopic hysterectomies were included in the analysis: 192 laparoscopic subtotal hysterectomies and 198 laparoscopic total hysterectomies. Patient characteristics such as age and parity were equal in the groups. The overall number of short-term and long-term complications was comparable in both groups: 17% and 15%. Short-term complications (bleeding, fever) were 3% in the LSH group and 12% in the LH group. Long-term complications were (tubal prolapse and cervical stump reoperations) 15% in the LSH group and 3% in the LH group. Laparoscopic subtotal hysterectomy as compared with the different types of laparoscopic total hysterectomy is associated with more long-term postoperative complications, whereas laparoscopic total hysterectomy is associated with more short-term complications