No abstract

The benefits of supplementing livestock diets with extracts from Yucca schidigera have been attributed to inhibition of selected gut microbes. The antimicrobial constituents were identified as three butanol-extractable 5β-spirostan-3β-ol saponins using Bacillus pasteurii and Saccharomyces cerevisiae as test prokaryotic and eukaryotic organisms, respectively. Although these saponins inhibited microbial growth at low cell densities, their impact was associated with adsorption to the microbes and they had no effect on dense microbial populations. The antimicrobial saponins were also observed to adsorb to the microbiota and other solids of the porcine cecum. The implications for gut microbes differ according to their ecological niche: Those sequestered to feed particles or the gut lining may accumulate saponins, whereas those flushed out synchronously with the digesta should be protected by high population densities.

Multiple myeloma (MM) is characterized by the clonal expansion and metastatic spread of malignant plasma cells to multiple sites in the bone marrow (BM). Recently, we implicated the sialyltransferase ST3Gal-6, an enzyme critical to the generation of E-selectin ligands, in MM BM homing and resistance to therapy. Since E-selectin is constitutively expressed in the BM microvasculature, we wished to establish the contribution of E-selectin ligands to MM biology. We report that functional E-selectin ligands are restricted to a minor subpopulation of MM cell lines which, upon expansion, demonstrate specific and robust interaction with recombinant E-selectin in vitro. Moreover, an increase in the mRNA levels of genes involved in the generation of E-selectin ligands was associated with inferior progression-free survival in the CoMMpass study. In vivo, E-selectin ligand-enriched cells induced a more aggressive disease and were completely insensitive to Bortezomib. Importantly, this resistance could be reverted by co-administration of GMI-1271, a specific glycomimetic antagonist of E-selectin. Finally, we report that E-selectin ligand-bearing cells are present in primary MM samples from BM and peripheral blood with a higher proportion seen in relapsed patients. This study provides a rationale for targeting E-selectin receptor/ligand interactions to overcome MM metastasis and chemoresistance.

: Y ucca schidigera was fractionated with butan-1-ol, yielding a butanolextractable (BE) fraction, containing all the in vitro antimicrobial activity, and the aqueous, non-butanol-extractable (NBE) fraction. Four groups of Ðve female rats (12 weeks old) were allowed ad libitum access to diets supplemented with water (control) or 200 mg kg~1 total Y schidigera (TOT) or its fraction equivalent of NBE or BE for 64 days. The e †ects of the fractions and their interactions in the TOT treatment were analysed according to the factorial experimental structure by two-way ANOVA. NBE reduced serum urea ([50%, P \ 0É019) and ammonia ([46%, P \ 0É037) concentrations, serum/urine concentration quotients of urea ([79%, P \ 0É009) and ammonia ([57%, P \ 0É002). NBE also reduced hindgut acetate/propionate ([12%, P \ 0É007) but increased faecal ammonia concentration (]87%, P \ 0É039). BE reduced hindgut indoles ([25%, P \ 0É023) and interacted synergystically with NBE in the TOT treatment to further reduce hindgut acetate/propionate by 6% (P \ 0É006). NBE increased (]27%, P \ 0É002) and BE decreased ([57%, P \ 0É005) hindgut urease activity levels, resulting in essentially no change (]4%) in the TOT treatment. The in vitro antimicrobial activity of Y schidigera is an unlikely explanation for most of its e †ects in vivo because these are caused by NBE and in vitro antimicrobial activity is exclusive to BE. Sarsasapogenin and smilagenin were also exclusive ([98%) to BE and cannot account for the e †ects of Y schidigera on N metabolism.1998 SCI. ( J Sci Food Agric 76, 91È99 (1998)

Nowadays, 70 % of global monogastric feeds contains an exogenous phytase. Phytase supplementation has enabled a more efficient utilisation of phytate phosphorous (P) and reduction of P pollution. Trace minerals, such as iron (Fe), zinc (Zn), copper (Cu) and manganese (Mn) are essential for maintaining health and immunity as well as being involved in animal growth, production and reproduction. Exogenous sources of phytase and trace elements are regularly supplemented to monogastric diets and usually combined in a premix. However, the possibility for negative interaction between individual components within the premix is high and is often overlooked. Therefore, this initial study focused on assessing the potential in vitro interaction between inorganic and organic chelated sources of Fe, Zn, Cu and Mn with three commercially available phytase preparations. Additionally, this study has investigated if the degree of enzyme inhibition was dependent of the type of chelated sources. A highly significant relationship between phytase inhibition, trace mineral type as well as mineral source and concentration, p < 0.001 was verified. The proteinate sources of OTMs were consistently and significantly less inhibitory than the majority of the other sources, p < 0.05. This was verified for Escherichia coli and Peniophora lycii phytases for Fe and Zn, as well as for Cu with E. coli and Aspergillus niger phytases. Different chelate trace mineral sources demonstrated diversifying abilities to inhibit exogenous phytase activity.

The trace mineral selenium (Se) is an essential element for human and animal nutrition. The addition of Se to the diet through dietary supplements or fortified food/feed is increasingly common owing to the often sub-optimal content of standard diets of many countries. Se supplements commercially available include the inorganic mineral salts such as sodium selenite or selenate, and organic forms such as Se-enriched yeast. Today, Se yeast is produced by several manufacturers and has become the most widely used source of Se for human supplementation and is also widely employed in animal nutrition where approval in all species has been granted by regulatory bodies such as the European Food Safety Authority (EFSA). Characterisation and comparison of Se-enriched yeast products has traditionally been made by quantifying total selenomethionine (SeMet) content. A disadvantage of this approach, however, is that it does not consider the effects of Se deposition on subsequent digestive availability. In this study, an assessment was made of the water-soluble extracts of commercially available Se-enriched yeast samples for free, peptide-bound and total water-soluble SeMet. Using LC-MS/MS, a total of 62 Se-containing proteins were identified across four Se yeast products, displaying quantitative/ qualitative changes in abundance relative to the certified reference material, SELM-1 (P value <0.05; fold change ≥2). Overall, the study indicates that significant differences exist between Se yeast products in terms of SeMet content, Secontaining protein abundance and associated metabolic pathways.

No abstract

Yucca schidigera Roezl ex Ortgies, family Lillaceae, was fractionated with butan-1-ol to yield a butanol extractable fraction (BE; saponin fraction) and a non-butanol fraction (NBE; non-saponin fraction). Four groups of eight male rats were allowed ad libitum access to diets supplemented with water (control) or 200 mg x kg(-1) total Y. schidigera (TOT) or 200 mg x kg(-1) of each of the fractions (NBE or BE). The effects of dietary supplementation with the fractions and their interactions in TOT were analyzed according to the factorial experimental design by two-way analysis of variance. All three supplementation groups displayed significantly reduced serum urea levels (P < 0.05). The TOT and NBE fractions were found to significantly increase serum insulin levels (P < 0.01) in the absence of any fluctuations in serum glucose levels. Urea cycle enzyme activities, namely, arginase (EC 3.5.3.1) and argininosuccinate lyase (EC 4.3.2.1), were significantly decreased (P < 0.05) in vivo, although no effect was observed in vitro. Both fractions displayed effects, indicating that the active constituents are present in both fractions.