Low Molecular Weight Subfractions Research Articles

Redox properties of compost-derived organic matter and their association with polarity and molecular weight

Compost-derived dissolved organic matter (DOM), which has a wide distribution of molecular weight (MW) and polarity, has a potential application in the remediation of the contaminated soil due to its redox-active functional groups. Composting treatment can change the MW and polarity of the DOM through microbial transformation and degradation. However, the relationship between the redox properties of compost-derived DOM and its MW and polarity is still unclear. DOM was extracted from municipal solid wastes with different composting times in this study, and it was further fractionated into humic acids (HA), fulvic acids (FA) and hydrophilic (HyI) fractions based on its hydrophobicity and XAD-8 resin. Electron transfer capacities [including electron accepting capacities (EAC) and electron donating capacities (EDC)] of the HA, FA and HyI fractions and their associations with polarity and MW were studied. The results showed that the EAC of the HA, FA and HyI all increased after composting. The EDC of the HA and HyI exhibited an increasing trend as well, though that of the FA decreased remarkably after composting. The MW, polarity and redox-active functional groups of the HA, FA and HyI fractions were determined using high performance liquid chromatography and excitation-emission matrix fluorescence spectra coupled with parallel factor analysis. The result showed that the quinone-like groups were mainly detected in the medium MW and transphilic sub-fractions of the HA, FA and HyI, and were the main functional groups responsible for the EAC. The low MW sub-fractions, which consisted mainly of tyrosine-like matter, were the main functional components accounted for the EDC. The results advance our understanding of the influence of MW and polarity on the redox properties of organic substances, and facilitate to reveal the important redox-active functional groups when compost is utilized to remediate the contaminated soil.

Antitumor potential of new low molecular weight antioxidative preparations from the white rot fungus Cerrena unicolor against human colon cancer cells

The aim of this study was to investigate the anticancer and antioxidant activities of low molecular weight subfractions isolated from secondary metabolites produced by the wood degrading fungus Cerrena unicolor. Human colon cancer cells (stage I) HT-29 and human normal colon epithelial cells CCD 841 CoTr were used in the research. The present study demonstrated that the low molecular weight subfractions exhibited inhibitory activity towards human colon cancer cells HT-29 at a concentration range of 25–200 μg/mL. All 6 subfractions inhibited proliferation of cells down to 47.5–9.2% at the highest concentrations in a dose-dependent manner. The most desired activity was exhibited by subfractions S, 3, 4, and 5, as the proliferation of HT-29 cells was inhibited to the greatest extent (16.5, 47.5, 42.7, and 26.1% of the control, respectively), while the effect on CCD 841 CoTr cells was the mildest (inhibition to 54.4, 71.4, 79.4, and 53.4%, compared to the control, respectively). The microscopic observation revealed that all extracts induced programmed cell death, i.e. apoptosis (up to 44.4% (subfraction 6) towards HT-29 and less than 20% (most fractions) towards CCD 841 CoTr), with no or a significantly low level of necrosis in both cell lines at the same time.

Anticancer, antioxidant, and antibacterial activities of low molecular weight bioactive subfractions isolated from cultures of wood degrading fungus Cerrena unicolor.

The aim of this study is to investigate in vitro the anticancer, antioxidant, and antibacterial activities of three low molecular weight subfractions I, II and III isolated from secondary metabolites produced by the wood degrading fungus Cerrena unicolor. The present study demonstrated that the low molecular weight subfractions III exhibited the strongest inhibitory activity towards breast carcinoma cells MDA-MB-231, prostatic carcinoma cells PC3, and breast cancer cells MCF7 with the half-maximal inhibitory concentration (IC50) value of 52,25 μg/mL, 60,66 μg/mL, and 54,92 μg/mL, respectively. The highest percentage of inhibition was noted at a concentration of 300 μg/mL in all the examined tumor lines. A significant percentage (59.08%) of ex-LMSIII inhibition of the MDA-MB-231 tumor line was reached at a concentration of 15 μg/ml, while the concentration applied did not affect normal human fibroblast cells. The low molecular weight subfraction III was the most effective and additionally showed the highest free radical 1,1-diphenyl-2-picryl-hydrazyl scavenging activity (IC50 20.39 μg/mL) followed by the low molecular weight subfraction I (IC50 64.14 μg/mL) and II (IC50 49.22 μg/mL). The antibacterial activity of the tested preparations was evaluated against three microorganisms: Bacillus subtilis, Staphylococcus aureus, and Escherichia coli. The MIC minimal inhibitory concentration (MIC) values for the low molecular weight subfraction I, II, and III showed a stronger inhibition effect on S. aureus than on B. subtilis and E. coli cells. The MIC values for the low molecular weight subfraction II against S. aureus, B. subtilis, and E. coli were 6.25, 12.5, and 100 mg/mL, respectively.

Abstract 2265: Sub-fractions of conditioned medium, from hypoxia-induced cells with multipotent potential, exhibit a significant anti-oncogenic activity

Abstract We have previously shown that a human soluble cell conditioned media (CCM) from hypoxia-induced, potentially multipotent cells, grown in a perfusion bioreactor system inhibits tumor cell growth in vitro and in two animal models. Here we present data that indicate that a low molecular weight sub-fraction from the CCM has an increased anti-oncogenic activity. This activity was demonstrated in orthotopic pancreatic models, nRAS melanoma assays and over 10 additional human cancer cell lines in vitro. In an orthotopic BxPC3 pancreatic cancer model, there was a statistically significant improvement in survival following weekly intravenous injections of 0.1ml of sub fractioned CCM, as well as a significant improvement with 0.5ml intraperitoneal injections post-resection, as measured by Kaplan Meier analysis (p<0.05) (figures below). Uveal and nRAS melanoma cancer cell growth was inhibited by greater than 90% in in-vitro proliferation assays. The mechanism of action of the CCM is the induction of apoptosis through the upregulation of Caspase 3 and 9, as demonstrated by immunostaining of Annexin V and immunoblot ayalysis. In a Miapaca nude mouse daily dose study, tumor mass and metastatic extent was substantially reduced in treated mouse versus the control. Further, in a BXPC3 nude mouse daily dose study, 60% (p<0.05) of treated mice were tumor free after four weeks of treatment, while only 10% were tumor free in the control group . Little or no apparent drug toxicity was observed. These results indicate that the CCM sub-fraction could be a useful raw material for a treatment for a large range of neoplastic diseases. Citation Format: Emmett Pinney, Mayra Montes-Camacho, Kayler Brintle, Christian Posch, Rhiana Menen, David Easter, Michael Bouvet, Robert Hoffman, Gail Naughton. Sub-fractions of conditioned medium, from hypoxia-induced cells with multipotent potential, exhibit a significant anti-oncogenic activity. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2265. doi:10.1158/1538-7445.AM2014-2265

Immunomodulatory Components Present in IMREG-1, an Experimental Immunosupportive Biologic

Human leukocyte dialysates contain substances capable of affecting human immune function. A low molecular weight subfraction derived from human leukocyte dialysates, IMREG-1, has been shown to enhance cell mediated immunity, and is under clinical evaluation as an immunosupportive agent in AIDS/ARC patients. We report here the isolation and amino acid sequences of two immunologically active peptides, Tyr-Gly and Tyr-Gly-Gly present in IMREG-1. These peptides have not previously been demonstrated to affect the immune system, and it is of interest to note that they are identical to the amino terminal ends of the enkephalins.

Inhibition of FSH action on granulosa cells by low molecular weight components of follicular fluid

Immature female rats were injected with a single dose (10 IU) of pregnant mare serum gonadotropin to induce growth and maturation of ovarian follicles. Using such ovaries as a model, we tested the effects of low molecular weight subfractions of charcoal-adsorbed bovine follicular fluid (FF-c) on (a) radioiodinated human FSH ( 125I-hFSH) binding to ovarian homogenates, (b) ovine FSH-stimulated adenylate cyclase activity in granulosa cell homogenates and (c) cAMP production by intact granulosa cells. The follicular fluid was fractionated by ultrafiltration through membranes of differing pore-sizes into low molecular weight components of 1000–5000 (passing Amicon HIP-5 hollow fibers but retained by Amicon UM-2 membrane) and 500–1000 (passing Amicon UM-2 membrane but retained by Amicon UM-05 membrane). These low molecular weight fractions inhibited 125I-hFSH binding to ovarian receptors, FSH-stimulated cAMP production by rat granulosa cells and FSH-stimulated, as well as fluoride-ion-stimulated adenylate cyclase activity in granulosa cell homogenates. Inhibition of FSH-stimulated adenylate cyclase activity by the FF subfractions was non-competitive as determined by double reciprocal plot analysis. Our results suggest that modulation of FSH effects on granulosa cells may be mediated by low molecular weight constituents of follicular fluid.

Mechanism of inhibitory effects of 2,3-dihydro-1,3-6H-oxazine-2,6-dione (3-oxauracil): Biosynthesis of 3-oxauridine phosphates in intact cells and cell-free extracts of Escherichia coli

The supernatant fraction of Escherichia coli cells treated with [ 14C]-2,3-dihydro-1,3-6H-oxazine-2,6-dione ([ 14C]-3-oxauracil) contains the principal portion of radioactivity in the low molecular weight subfraction. The dominant component of this subfraction is a compound with the properties of 3-oxauridine 5′-monophosphate. The compound is also formed from 3-oxauracil and 5-phosphoribosyl 1-pyrophosphate on incubation with the cell-free extract of E. coli. If this incubation mixture is enriched with adenosine 5′-triphosphate, two further compounds are formed, their properties corresponding to 3-oxauridine 5′-di- and -triphosphates. Treatment of the compound possessing properties of 3-oxauridine 5′-triphosphate with snake venom yielded a non-nucleotide compound with a lower chromatographic mobility than authentic 3-oxauridine. This compound appears to be a ribonucleoside with an open oxazine ring.

Built-in hapten inhibition of anaphylaxis by the low molecular weight subfractions of a B 512 dextran fraction of MW 3,400.

(1) Passive antidextran dextran anaphylaxis was produced in guinea pigs challenged with B 512 dextran fractions or subfractions. By Sephadex separation of a weakly anaphylactogenic parent dextran fraction of weight average molecular weight (M<sub>w</sub>) 3,400 subfractions of widely varying M<sub>w</sub> and anaphylactogenicity were obtained. (2) The weakly anaphylactogenic parent fraction produced no mortality, whereas its most anaphylactogenic subfraction produced 80% mortality. Calculations showed, that the parent dextran fraction was composed of non- or weakly anaphylactogenic and strongly anaphylactogenic subfractions, occurring in a molar ratio of 3:1. (3) Built-in hapten inhibition was thus exerted within the parent dextran fraction by its low molecular weight subfractions, reducing the anaphylactogenicity of the higher molecular subfractions. Generally, the lower the average molecular weight of a homopolymer fraction, the more pronounced should be the effect of built-in inhibition. (4) It is proposed to designate this built-in hapten inhibition of fractions of dextran or other homopolymers as ‘inherent’ hapten inhibition, in contrast to that produced by adding low molecular, non-anaphylactogenic fractions to higher molecular, anaphylactogenic fractions upon challenge of sensitized animals.