Purification and characterisation of a xylose-specific mitogenic lectin from Fusarium sambucinum

A xylose-specific intracellular lectin, showing hemagglutination only with rabbit erythrocytes was purified from mycelium of Fusarium sambucinum which was designated as FSL. An array of anion exchange chromatography on Q-Sepharose and gel-exclusion chromatography on Sephadex G-100 resulted in 84.21% yield and 53.99-fold purification of lectin with specific activity of 169.53 titre/mg. Molecular weight of FSL determined by SDS-PAGE was 70.7 kDa, which was further confirmed by gel-exclusion chromatography. Native-PAGE analysis of FSL showed its monomeric nature. FSL was observed to be a glycoprotein containing 2.9% carbohydrate. Hapten inhibition profile of FSL displayed its strong affinity towards D-xylose (MIC 1.562 mM), L-fucose (MIC 6.25 mM), D-mannose (MIC 3.125 mM), fetuin (MIC 15.62 μg/mL), asialofetuin (MIC 125 μg/mL) and BSM (MIC 3.125 μg/mL). Affinity of FSL towards xylose is rare. FSL was found stable over a pH range 6.0-7.5 and upto 40 °C temperature. Hemagglutination activity of FSL remained unaffected by divalent ions. Lectin concentration of 5 μg/mL was found sufficient to stimulate proliferation of murine spleen cells and its concentration 75 μg/mL exhibited highest mitogenic potential. FSL exhibited maximum mitogenic stimulatory index of 14.35. The purification, characterisation and mitogenicity of F. sambucinum lectin has been reported first time.

Abstract P2-12-12: MyNauseaRisk assay - Predicting chemotherapy-induced delayed nausea using a blood-based assay

BACKGROUND: Nausea and vomiting are some of the most common and distressing side effects of chemotherapy according to patients. Chemotherapy-induced nausea and vomiting (CINV) places a substantial burden on patients and their loved ones, which greatly reduces the quality of life, nutritional habits, ability to work and socialize, and adhere to treatment regimens. Therefore, assessment of CINV is an essential component of care for patients receiving chemotherapy. Multiple factors influence the incidence of CINV with the chemotherapy regimen, both type and dosage, being the primary risk factor. It is generally assumed that the strongest patient-related factors are younger age and female sex. However, reports in the literature have demonstrated that using these factors clinicians underestimate the prevalence of CINV, especially delayed nausea. Thus, there is a need for risk assessment tools to accurately identify patients requiring anti-emetic regimens to improve quality of life of patients and their families. Our assay is based on the knowledge that chemotherapeutic agents cause bursts of reactive oxygen species (ROS) resulting in cellular damage and release of substances that activate receptors in the chemoreceptor trigger zone. Glutathione (GSH), a key antioxidant, is responsible for maintaining redox homeostasis by neutralizing ROS. Therefore, we hypothesized that a patient’s risk of CINV may reflect individual variations in the efficiency to scavenge and neutralize ROS after chemotherapy.

METHODS: Patients enrolled in our institutional review board approved study (N= 220), were treated in the adjuvant or neoadjuvant setting with highly or moderately emetogenic chemotherapies for their breast cancer diagnosis. Blood samples were drawn from chemotherapy naïve patients and used in the predictive blood assay. The assay is based on the conversion of a bioactive probe, hydroxyethyl disulfide, into mercaptoethanol, which once normalized to red blood cell count, indicates glutathione recycling capacity. Incidence and severity of delayed nausea symptoms were collected from notes in medical records as well as anti-emetic prescription history.

RESULTS: A recent second evaluation of patients treated with platinum-based therapies confirmed our previously published data, demonstrating a correlation between low glutathione recycling capacity and risk of delayed nausea for patients with lung and colon cancer (N=111; misclassification rate 0.153; AUC 0.72). In this study, we evaluated age-matched patients treated with anthracycline/cyclophosphamide (AC)(N=42), docetaxel/cyclophosphamide (TC)(N=39), docetaxel/carboplatin/trastuzumab (TCH)(N=27) or docetaxel/carboplatin/trastuzumab/pertuzumab (TCHP)(N=25). The incidence of moderate-to-severe nausea was highest in the AC (38.1%) and TCHP (36.0%) groups. The TCH group had the lowest incidence of patients (11%) reporting delayed nausea. SAS/STAT v.14.1 classification trees demonstrated a weak association between anthracycline-induced delayed nausea and MyNauseaRisk score (misclassification rate 0.333; AUC 0.67). Similarly, patients treated with TC demonstrated a correlation between MyNauseaRisk score and severity of nausea as previously seen for platinum therapies. The algorithm determined that age stratification of patients in the TCHP group prior to applying the MyNauseaRisk score reduced the misclassification rate (0.280) and improved the AUC (0.72).

CONCLUSION: The results from this exploratory prospective study suggests that a reduced ability to recycle GSH in the blood may offer an objective prediction of delayed nausea, possibly allowing for optimal anti-emetic regimen to improve the quality-of-life for breast cancer patients.

Citation Format: Nicole F Laslett, Dillon D McCourt, Kinjal Parikh, John F Kennedy, Zonera A Ali, Erik L Zeger, Aarti L Shevade, Tracey L Evans, Paul B Gilman, Margaretha Wallon. MyNauseaRisk assay - Predicting chemotherapy-induced delayed nausea using a blood-based assay [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-12-12.

Chitosan induces resistance to tuber rot in stored potato caused by Alternaria tenuissima

Alternaria tenuissima infects stored potatoes, and causes tuber rot, resulting in significant economic losses. As a naturally-occurring polysaccharide (poly-β-(1 → 4) N-acetyl-D-glucosamine), chitosan has been reported to be an eco-friendly alternative to synthetic fungicides for the control of postharvest diseases on agricultural commodities. In this study, application of 0.25-1.25 g/L chitosan significantly inhibited spore germination and mycelial growth of A. tenuissima in vitro, with the greatest inhibitory effect observed at the highest concentration. Cytological and biochemical analysis of A. tenuissima spores indicated that exposure to 1.25 g/L chitosan significantly damaged the plasma membrane and increased the level of lipid oxidation. Gene expression analysis in potato tuber revealed that an application of 1.25 g/L chitosan induced the expression of defense-related genes, including catalase, peroxidase, polyphenol oxidase, chitinase and β-1,3-glucanase, and the level of flavonoids and lignin. Chitosan effectively controlled tuber rot caused by A. tenuissima. Collectively, results of the current study indicate that the ability of chitosan to reduce Alternaria rot in stored potato tubers is due to its direct antifungal activity and its ability to induce defense responses in potato tuber tissues. Chitosan may have the potential as a substitute for synthetic fungicides to reduce postharvest losses in potato.

Fructose production from inulin using fungal inulinase immobilized on 3-aminopropyl-triethoxysilane functionalized multiwalled carbon nanotubes

The main objective of the present work was to modify multiwalled carbon nanotubes (MWCNTs) using 3-aminopropyl-triethoxysilane (APTES) to generate amino-terminated surfaces for inulinase immobilization, which can be further used for fructose production. CCRD of response surface methodology was used for optimization of inulinase immobilization on MWCNTs. At optimized parameters (APTES concentration 4%; sonication time 4 h; enzyme coupling time 1.5 h and enzyme load 15 IU), maximal inulinase activity and immobilization yield was 60.7% and 74.4%, respectively. Immobilized inulinase showed same pH optima of free enzyme, while an elevation in temperature optima to 60 °C was observed after its immobilization. Immobilized inulinase also shown enhancement in pH stability and thermostability. Overall, 4.54-fold rise in half-life of inulinase was detected after immobilization at 60 °C. K_m and V_max of inulinase decreased after immobilization. Immobilized inulinase preserved 28% of its residual activity after 10 consecutive batch cycles of inulin hydrolysis for the production of fructose.

Anti-oxidant mediated normalisation of raised intracellular cytokines in patients with reproductive failure

Background

Raised intracellular cytokine ratios (CKR) are proposed as a significant risk factor for adverse reproductive outcome. An elevated cytokine ratio, such as between TNFa and/or IFNg to IL-10 is associated with recurrent miscarriage (RM). The use of pharmacological immunomodulators such as TNFα inhibitors in these patients is controversial and not generally recommended due to a lack of conclusive data supporting their use. We evaluated whether the use of anti-oxidants/dietary supplements as an alternative could positively influence CKR’s in ART patients.

Methods

A prospective non-placebo control trial of antioxidant treatment for abnormal peripheral inflammatory cytokine ratios was performed. CKRs were assessed using flow cytometry in stimulated versus unstimulated whole blood samples in 337 IVF patients presenting with a previous history of poor outcome (RM or implantation failure). CKR’s were found to be elevated in 150/337. 70/150 patients in this elevated group agreed to a 10 week regime of Omega 3, vitamin D3, and B complex, followed by retesting to evaluate effect.

Results

Mean cytokine ratios significantly improved between tests. Pre-treatment TNFa:IL-10 ratio improved from 71.6 to 21.0 (p < 0.0001) and IFNg:IL-10 ratio dropped from 24.5 to 12.5 (p < 0.0001). The improved ratios were achieved primarily by an increase in IL-10 expression (P = 0.0007), but also by a moderate decrease in stimulated TNFa expression (p = 0.008). Mean IFNg expression was unchanged (p = 0.42). On an individual basis CKR levels were normalised in 43 patients, improved in 12 and remained unchanged in 15. No significant differences in improvement were found between RM and IF subgroups.

Conclusions

Intracellular cytokine expression levels and ratios were modifiable by the supplement regime employed. Elevated cytokine ratios have been linked with adverse reproductive outcomes, and proposed treatments have included biological immunomodulators which antagonise TNFa, but come with significant associated cost implications and more importantly, cytotoxic side-effects. A dietary regime is more patient friendly and lower risk, while still achieving a similar effect in many patients.

Cyanobacterial lectins characteristics and their role as antiviral agents

Lectins are ubiquitous proteins/glycoproteins of non-immune origin that bind reversibly to carbohydrates in non-covalent and highly specific manner. These lectin-glycan interactions could be exploited for establishment of novel therapeutics, targeting the adherence stage of viruses and thus helpful in eliminating wide spread viral infections. Here the review focuses on the haemagglutination activity, carbohydrate specificity and characteristics of cyanobacterial lectins. Cyanobacterial lectins exhibiting high specificity towards mannose or complex glycans have potential role as anti-viral agents. Prospective role of cyanobacterial lectins in targeting various diseases of worldwide concern such as HIV, hepatitis, herpes, influenza and ebola viruses has been discussed extensively. The review also lays emphasis on recent studies involving structural analysis of glycan-lectin interactions which in turn influence their mechanism of action. Altogether, the promising approach of these cyanobacterial lectins provides insight into their use as antiviral agents.

Chitosan and oligochitosan enhance ginger (Zingiber officinale Roscoe) resistance to rhizome rot caused by Fusarium oxysporum in storage

The ability of chitosan and oligochitosan to enhance ginger (Zingiber officinale) resistance to rhizome rot caused by Fusarium oxysporum in storage was investigated. Both chitosan and oligochitosan at 1 and 5g/L significantly inhibited rhizome rot, with the best control at 5g/L. Chitosan and oligochitosan applied at 5g/L also reduced weight loss, measured as a decrease in fresh weight, but did not affect soluble solids content or titratable acidity of rhizomes. The two compounds applied at 5g/L induced β-1,3-glucanase and phenylalanine ammonia-lyase enzyme activity and the transcript levels of their coding genes, as well as the total phenolic compounds in rhizome tissues. Therefore, the ability of chitosan and oligochitosan to reduce rot in stored rhizomes may be associated with their ability to induce defense responses in ginger. These results have practical implications for the application of chitosan and oligochitosan to harvested ginger rhizomes to reduce postharvest losses.