Influence of water activity in the synthesis of galactooligosaccharides produced by a hyperthermophilic beta-glycosidase in an organic medium

The present study evaluated the influence of water activity and lactose concentration on the synthesis of galactooligosaccharides (GOS), by means of a hyperthermophilic beta-glycosidase in an organic system. The production of GOS gradually grew as water activity increased in the reaction system; later, their synthesis decreased as water activity increased. The authors used the response surface methodology to study how different water activities and different concentrations of lactose influenced the synthesis of GOS and their length. In every case, the variable that proved to have the greatest effect on GOS synthesis was water activity. Maximum GOS3 synthesis was reached at a water activity interval of 0.44-0.57, with lactose concentrations of 0.06%-0.1%, while GOS4 and GOS5 maxima were reached at water activity intervals of 0.47-0.57 and 0.49-0.60, respectively. The research showed that higher water activity was required to synthesize GOS of greater length. Synthesis of GOS would then depend on the flexibility of the enzyme, which in turn would depend on water activity of the reaction system. This hypothesis was supported by experiments in which the reaction temperature was modified in order to change the flexibility of the enzyme, thus leading to longer GOS.     

Prognostic factors for early relapse in non-metastatic triple negative breast cancer — real world data

BackgroundTriple negative breast cancer (TNBC) has the worst prognosis amongst all subtypes. Studies have shown that the achievement of pathologic complete response in the breast and axilla correlates with improved survival. The aim of this study was to identify clinical or pathological features of real-life TNBC patients with a higher risk of early relapse.Materials and methodsSingle-centre retrospective analysis of 127 women with TNBC, stage II–III, submitted to neoadjuvant treatment and surgery between January 2016 and 2020. Multivariate Cox regression analysis for disease free survival (DFS) at 2 years was performed and statistically significant variables were computed into a prognostic model for early relapse.ResultsAfter 29 months of median follow-up, 105 patients (82.7%) were alive and, in total, 38 patients (29.9%) experienced recurrence. The 2-year DFS was 73% (95% CI: 21.3–22.7). In multivariate analysis, being submitted to neoadjuvant radiotherapy [HR 2.8 (95% CI: 1.2–6.4), p = 0.017] and not achieving pathologic complete response [HR 0.3 (95% CI: 0.1–1.7), p = 0.011] were associated with higher risk of recurrence. In our prognostic model, the presence of at least one of these variables defined a subgroup of patients with a worse 2-year DFS than those without these features (59% vs. 90%, p < 0.001, respectively).ConclusionsIn this real-life non-metastatic TNBC cohort, neoadjuvant radiotherapy (performed due to insufficient clinical response to neoadjuvant chemotherapy or significant toxicity) impacted as an independent prognostic factor for relapse along with the absence of pathologic complete response identifying a subgroup of higher risk patients for early relapse that might merit a closer follow-up.     

A novel dendrimeric peptide with antimicrobial properties: structure-function analysis of SB056

The novel antimicrobial peptide with a dimeric dendrimer scaffold, SB056, was empirically optimized by high-throughput screening. This procedure produced an intriguing primary sequence whose structure-function analysis is described here. The alternating pattern of hydrophilic and hydrophobic amino acids suggests the possibility that SB056 is a membrane-active peptide that forms amphiphilic β-strands in a lipid environment. Circular dichroism confirmed that the cationic SB056 folds as β-sheets in the presence of anionic vesicles. Lipid monolayer surface pressure experiments revealed unusual kinetics of monolayer penetration, which suggest lipid-induced aggregation as a membranolytic mechanism. NMR analyses of the linear monomer and the dendrimeric SB056 in water and in 30% trifluoroethanol, on the other hand, yielded essentially unstructured conformations, supporting the excellent solubility and storage properties of this compound. However, simulated annealing showed that many residues lie in the β-region of the Ramachandran plot, and molecular-dynamics simulations confirmed the propensity of this peptide to fold as a β-type conformation. The excellent solubility in water and the lipid-induced oligomerization characteristics of this peptide thus shed light on its mechanism of antimicrobial action, which may also be relevant for systems that can form toxic β-amyloid fibrils when in contact with cellular membranes. Functionally, SB056 showed high activity against Gram-negative bacteria and some limited activity against Gram-positive bacteria. Its potency against Gram-negative strains was comparable (on a molar basis) to that of colistin and polymyxin B, with an even broader spectrum of activity than numerous other reference compounds.     

S-layer proteins of Lactobacillus acidophilus inhibits JUNV infection

We investigated the regulation of Hsp27 phosphorylation by protein kinase C δ (PKCδ) during etoposide-induced apoptosis. The phosphorylation of Hsp27 at Ser78 was temporally correlated with the proteolytic activation of PKCδ during apoptosis. Hsp27 phosphorylation was dependent on the activity of PKCδ since treatment with rottlerin, a chemical inhibitor of PKCδ, or overexpression of a PKCδ dominant negative mutant abolished the phosphorylation. In addition, recombinant PKCδ phosphorylated Hsp27 at Ser78 in vitro. Moreover, caspase-3 was specifically activated following Hsp27 phosphorylation at Ser78. Pull-down assays using a phosphomimetic Hsp27 mutant revealed that binding between Hsp27 and cytochrome c was abolished by the phosphorylation. These results suggest that Hsp27 dissociates from cytochrome c following PKCδ-mediated phosphorylation at Ser78, which allows formation of the apoptosome and stimulates apoptotic progression.     

Direct analysis of bacterial viability in endotracheal tube biofilm from a pig model of methicillin-resistant Staphylococcus aureus pneumonia following antimicrobial therapy

Confocal laser scanning microscopy (CLSM) helps to observe the biofilms formed in the endotracheal tube (ETT) of ventilated subjects and to determine its structure and bacterial viability using specific dyes. We compared the effect of three different treatments (placebo, linezolid, and vancomycin) on the bacterial biofilm viability captured by CLSM. Eight pigs with pneumonia induced by methicillin-resistant Staphylococcus aureus (MRSA) were ventilated up to 96?h and treated with linezolid, vancomycin, or placebo (controls). ETT images were microscopically examined after staining with the live/dead(?) BacLight(?) Kit (Invitrogen, Barcelona, Spain) with a confocal laser scanning microscope. We analyzed 127 images obtained by CLSM. The median ratio of live/dead bacteria was 0.51, 0.74, and 1 for the linezolid, vancomycin, and control groups, respectively (P?=?0.002 for the three groups); this ratio was significantly lower for the linezolid group, compared with the control group (P?=?0.001). Images showed bacterial biofilm attached and non-attached to the ETT surface but growing within secretions accumulated inside ETT. Systemic treatment with linezolid is associated with a higher proportion of dead bacteria in the ETT biofilm of animals with MRSA pneumonia. Biofilm clusters not necessarily attach to the ETT surface.     

Identification of ETP-46321, a potent and orally bioavailable PI3K α, δ inhibitor

Phosphoinositide-3-kinase (PI3K) is an important target for cancer therapeutics due to the deregulation of this signaling pathway in a wide variety of human cancers. Herein, we describe the optimization of imidazo [1,2-a] pyrazines, which allow us to identify compound 14 (ETP-46321), with potent biochemical and cellular activity and good pharmacokinetic properties (PK) after oral dosing. ETP-46321 PK/PD studies showed time dependent downregulation of AKT(Ser473) phosphorylation, which correlates with compound levels in tumor tissue and demonstrating to be efficacious in a GEMM mouse tumor model driven by a K-Ras(G12V) oncogenic mutation. Treatment with ETP-46321 resulted in significant tumor growth inhibition.     

Rapid identification of ETP-46992, orally bioavailable PI3K inhibitor, selective versus mTOR

Phosphoinositide-3-kinases (PI3K) are a family of lipid kinases mediating numerous cell processes such as proliferation, migration and differentiation. PI3K is an important target for cancer therapeutics due to the deregulation of this signaling pathway in a wide variety of human cancers. Herein, we describe the rapid identification of ETP-46992, within 2-aminocarbonyl imidazo [1,2-a] pyrazine series, with suitable pharmacokinetic (PK) properties that allows the establishment of mechanism of action and efficacy in vivo studies. ETP-46992 showed tumor growth inhibition in a GEMM mouse tumor model driven by a K-Ras(G12V) oncogenic mutation and in tumor xenograft models with PI3K pathway deregulated (BT474).     

Cellular associations of pituitary gonadotrophs in a rodent (Lagostomus maximus maximus) with photoperiod-dependent reproduction

The morphological characteristics and percentage of the cellular associations between gonadotrophs (LH- and FSH-secreting cells) and other cellular types were studied in pituitary pars distalis of adult male viscachas (Lagostomus maximus maximus) by double immunohistochemistry using specific antibodies to LH, FSH, PRL, GH, ACTH, TSH and S-100 protein (by folliculostellate cells; FSC), during long and short photoperiods. Bihormonal gonadotrophs were observed in ventro-medial and dorsal regions, interspersed between monohormonal gonadotrophs, and their number increased in short photoperiod. LH- and FSH-gonadotrophs were found around lactotrophs, enclosed by somatotrophs in the dorsal region, and associated with irregular corticotrophs. Gonadotrophs and thyrotrophs were associated along blood vessels and follicular structures. The cytoplasmic prolongations of FSC were in contact with both gonadotrophs. The percentage of LH–FSH, LH–ACTH, LH–FSC, FSH–LH, FSH–PRL, FSH–GH, FSH–ACTH, FSH–TSH and FSH–FSC associations decreased, whereas LH–PRL increased in short as compared to long photoperiod. The most abundant associations were LH–GH and LH–TSH during long photoperiod, but LH–GH and LH–PRL during short photoperiod. FSH–GH and FSH–PRL were the most numerous associations, and LH–FSC and FSH–FSC were the less abundant ones in both photoperiods. These results provide the morphological evidence for specific cellular associations between gonadotrophs and other cellular types of viscacha pituitary.     

Synthesis and biological evaluation of colchicine C-ring analogues tethered with aliphatic linkers suitable for prodrug derivatisation

Colchicine was modified at the 10-OCH₃ position of the C-ring by reaction with heterocyclic amines or commercially available amines to afford a library of target colchicinoids in high yields (62–99%). Molecular modeling revealed that the incorporation of the linker groups led to a reduction in entropy and therefore binding affinity when compared with colchicine. Some colchicinoids were shown to be equicytotoxic with colchicine when evaluated in the DLD-1 colon cancer cells and retained activity in resistant A2780AD or HeLa cells with mutant Class III β-tubulin. Importantly, unlike colchicine, the analogues in this study are amenable for prodrug derivatisation and with potential for tumor-selective delivery.