MicroRNA-21 as a predictor and prognostic factor for trastuzumab therapy in human epidermal growth factor receptor 2-positive metastatic breast cancer

Breast cancer is the second most common cancer diagnosed worldwide. Human epidermal growth factor receptor 2 (HER2)-positive breast cancer represents about 20% to 30% of all breast cancers. Trastuzumab is used in the treatment of HER2-positive breast cancer. MicroRNA-21 (miR-21) is an oncomiR that acts by inhibiting many tumor-suppressor genes. We analyzed the relative expression levels of serum miR-21 in 20 HER2-positive metastatic breast cancer patients before and after 3 months of treatment with trastuzumab. miR-21 levels decreased with a high significant difference after trastuzumab therapy (P = 0.001). Although miR-21 expression levels were lower in responders than in nonresponders, the difference was not statistically significant ( P = 0.6). Our results demonstrated a significant negative correlation between its basal expression, expression levels after treatment, and time to progression ( P = 0.03 and 0.01, respectively). These results make miR-21 a potential prognostic factor for HER2-positive metastatic breast cancer patients. Additionally, it can be an interesting potential target in therapy using antisense oligonucleotides for miR-21.     

Effect of Cystoseira barbata and Dictyota dichotoma-algae on reproduction and protein pattern of Biomphalaria alexandrina snails

Controlling the snail intermediate host of schistosomiasis is one of the strategies used to reduce disease incidence. In this study screening tests were carried out on the action of dried powder of eight algal species against Biomphalaria alexandrina snails. The most effective powders were from Dictyota dichotoma and Cystoseira barbata with LC₅₀ values of 560 and 2200?ppm, respectively. Prolonged exposure to sublethal concentrations of these two powders caused adverse effects on snails' reproduction especially at LC₂₅. Hatchability of exposed eggs was lowest at LC₂₅ of C. barbata, and LC₁₅ of D. dichotoma. The most pronounced effects on the hermaphrodite gland of snails were caused by high concentrations of both algal suspensions, where ova were either degenerated or deformed and there were detrimental effects on all spermatogenesis stages. The electrophoretic separation of haemolymph proteins showed that the concentration with most effect was the LC₁₅ for both tested algae as they resulted in more bands than the control and also an elevation in total protein content.     

Excess Linoleic Acid Increases Collagen I/III Ratio and “Stiffens” the Heart Muscle Following High Fat Diets

Controversy exists on the benefits versus harms of n-6 polyunsaturated fatty acids (n-6 PUFA). Although n-6 PUFA demonstrates anti-atherosclerotic properties, survival following cardiac remodeling may be compromised. We hypothesized that n-6 PUFA like linoleic acid (LA) or other downstream PUFAs like γ-linolenic acid or arachidonic acid alter the transforming growth factor-β (TGFβ)-collagen axis in the heart. Excess dietary LA increased the collagen I/III ratio in the mouse myocardium, leading to cardiac “stiffening” characterized by impaired transmitral flow indicative of early diastolic dysfunction within 5 weeks. In vitro, LA under TGFβ1 stimulation increased collagen I and lysyl oxidase (LOX), the enzyme that cross-links soluble collagen resulting in deposited collagen. Overexpression of fatty acid desaturase 2 (fads2), which metabolizes LA to downstream PUFAs, reduced collagen deposits, LOX maturation, and activity with LA, whereas overexpressing fads1, unrelated to LA desaturation, did not. Furthermore, fads2 knockdown by RNAi elevated LOX activity and collagen deposits in fibroblasts with LA but not oleic acid, implying a buildup of LA for aggravating such pro-fibrotic effects. As direct incubation with γ-linolenic acid or arachidonic acid also attenuated collagen deposits and LOX activity, we concluded that LA itself, independent of other downstream PUFAs, promotes the pro-fibrotic effects of n-6 PUFA. Overall, these results attempt to reconcile opposing views of n-6 PUFA on the cardiovascular system and present evidence supporting a cardiac muscle-specific effect of n-6 PUFAs. Therefore, aggravation of the collagen I/III ratio and cardiac stiffening by excess n-6 PUFA represent a novel pathway of cardiac lipotoxicity caused by high n-6 PUFA diets.     

The novel steroidal alkaloids dendrogenin A and B promote proliferation of adult neural stem cells

Dendrogenin A (DDA) and dendrogenin B (DDB) are new aminoalkyl oxysterols which display re-differentiation of tumor cells of neuronal origin at nanomolar concentrations. We analyzed the influence of dendrogenins on adult mice neural stem cell proliferation, sphere formation and differentiation. DDA and DDB were found to have potent proliferative effects in neural stem cells. Additionally, they induce neuronal outgrowth from neurospheres during in vitro cultivation. Taken together, our results demonstrate a novel role for dendrogenins A and B in neural stem cell proliferation and differentiation which further increases their likely importance to compensate for neuronal cell loss in the brain.     

Study of enhancement and inhibition phenomena and genes relating to degradation of petroleum polycyclic aromatic hydrocarbons in isolated bacteria

Polycyclic aromatic hydrocarbons (PAHs) are xenobiotic compounds, which being degraded by chemical, physical or biological methods. The latter is the safest and the cheapest one. Two bacterial strains ASU-01 and ASU-016 were isolated from different Egyptian petroleum contaminated sites. They were genetically identified based on the analysis of the nucleotide sequences of the 16S ribosomal PNA gene and the phylogenetic tree as Enterobacter hormaechei and Pseudomonas pseudoalcaligenes respectively. When pyrene as high molecular weight (HMW)-PAH was added as a sole carbon source, both strains could degrade it with efficiency 77.7 and 83.7% within 15 days of incubation, respectively. However, when it was mixed with low molecular weight (LMW)-PAHs, two opposite phenomena appeared. The first one was enhancement, which occurred with ASU-01. This strain shifted pyrene efficiency to 98.5%. The second phenomenon was inhibition occurred with ASU-016 which completely retarded pyrene degradation. Naphthalene dioxygenase (nahAc), and catechol dioxygenases (C12O and C23O) genes were detected in the two strains based on PCR. The detected genes were confirmed by determining the different specific activities of their translated protein (enzymes) on different PAHs. The maximum values of biosurfacatant production activity and cell-surface and percentage of cell-surface hydrophobicity (CSH) were detected during the exponential phase. These latter factors increased the bioavailability and consequently, the assimilation of PAHs.     

Cilioprotists as biological indicators for estimating the efficiency of using Gravel Bed Hydroponics System in domestic wastewater treatment

Interest has increased over the last several years in using different methods for treating sewage. The rapid population growth in developing countries (Egypt, for example, with a population of more than 87 millions) has created significant sewage disposal problems. There is therefore a growing need for sewage treatment solutions with low energy requirements and using indigenous materials and skills. Gravel Bed Hydroponics (GBH) as a constructed wetland system for sewage treatment has been proved effective for sewage treatment in several Egyptian villages. The system provided an excellent environment for a wide range of species of ciliates (23 species) and these organisms were potentially very useful as biological indicators for various saprobic conditions. Moreover, the ciliates provided excellent means for estimating the efficiency of the system for sewage purification. Results affirmed the ability of this system to produce high quality effluent with sufficient microbial reduction to enable the production of irrigation quality water.     

Biocontrol of apple blue mould by new yeast strains: Cryptococcus albidus KKUY0017 and Wickerhamomyces anomalus KKUY0051 and their mode of action

Seeking new yeast strains having the ability to protect apple fruits against blue mould for a long time under different storage conditions was the main goal of this work. Based on the in vitro test, yeast strains KKUY0017 and KKUY0051 were selected as the most effective antagonists against Penicillium expansum. Sequencing of 26S rDNA of both yeasts confirmed that the identity of KKUY0017 and KKUY0051 was Cryptococcus albidus and Wickerhamomyces anomalus, respectively. The two strains protected the apple fruits from the blue mould disease under a wide range of temperature (5–30°C); however, W. anomalus KKUY0051 was more effective. At 25°C, W. anomalus KKUY0051 involved in the reduction of disease severity and disease incidence of blue mould by 56.49% and 57.78%, respectively. When either of the two yeasts was applied in concentration of 10⁸ or 10⁹ cells/mL, the maximum reduction in disease severity and disease incidence was achieved. Under cold storage (5°C), both yeast strains succeeded to protect the apple fruits free from the infection up to 24 days. Electron micrograph showed a fit attachment between the cells of C. albidus KKUY0017 and the fungal hyphae leading to the degrading of the hyphae; however, W. anomalus killed the fungal hyphae without direct attachment to them. Gas chromatography–mass spectrometry analysis of the cell-free extract of W. anomalus KKUY0051 revealed the presence of toxic compounds such as the nitrophenol derivatives. The results support the assumption that the main mode of action of this yeast is by killer toxins. We conclude that application of these yeasts under cold storage condition could keep the apple fruits free from blue mould infection for a long time.     

Molecular screening of Streptomyces isolates for antifungal activity and family 19 chitinase enzymes

Thirty soil-isolates of Streptomyces were analyzed to determine their antagonism against plant-pathogenic fungi including Fusarium oxysporum, Pythium aristosporum, Colletotrichum gossypii, and Rhizoctonia solani. Seven isolates showed antifungal activity against one or more strain of the tested fungi. Based on the 16S rDNA sequence analysis, these isolates were identified as Streptomyces tendae (YH3), S. griseus (YH8), S. variabilis (YH21), S. endus (YH24), S. violaceusniger (YH27A), S. endus (YH27B), and S. griseus (YH27C). The identity percentages ranged from 98 to 100%. Although some isolates belonged to the same species, there were many differences in their cultural and morphological characteristics. Six isolates out of seven showed chitinase activity according to a chitinolytic activity test and on colloidal chitin agar plates. Based on the conserved regions among the family 19 chitinase genes of Streptomyces sp. two primers were used for detection of the chitinase (chiC) gene in the six isolates. A DNA fragment of 1.4 kb was observed only for the isolates YH8, YH27A, and YH27C. In conclusion, six Streptomyces strains with potential chitinolytic activity were identified from the local environment in Taif City, Saudi Arabia. Of these isolates, three belong to family 19 chitinases. To our knowledge, this is the first reported presence of a chiC gene in S. violaceusniger YH27A.     

Hypolipidemic and antioxidant effects of Morus alba L. (Egyptian mulberry) root bark fractions supplementation in cholesterol-fed rats

The 70% alcohol extract of the Egyptian Morus alba L. root bark was fractionated over cellulose CC eluted with water, 50% methanol and finally with 100% methanol to yield 3 fractions (MRBF-1, MRBF-2 and MRBF-3), respectively. In continuation of chromatographic purification of 70% alcohol extract fractions of the Egyptian M. alba L. root bark, 4 compounds namely: mulberroside A, 5,7,2'-trihydroxyflavanone-4'-O-beta-D-glucoside and albanols A and B were isolated from MRBF-2 for the first time from the Egyptian plant. Experimentally induced atherosclerosis was produced by feeding rats a diet enriched in coconut oil (25% by weight) and cholesterol (2% by weight) for 21 days. Then, hypercholesterolemic rats were orally administered (MRBF-1, MRBF-2 and MRBF-3 fractions) in a dose of 500 mg kg(-1) day(-1) for 15 successive days, in order to evaluate their expected hypocholesterolemic activity. Lipid profile parameters such as plasma total cholesterol, LDL-C, VLDL-C, LDL:HDL ratio and triglycerides, as well as plasma and liver lipid peroxides and glutathione-S-transferase enzyme levels, serum paraoxonase enzyme level, LDL oxidation, LDL aggregation and LDL retention, were measured. Plasma and liver glutathione-S-transferase enzyme levels were unaffected in all studied groups. The results revealed that the administration of (MRBF-2 and/or MRBF-3) fractions resulted in alleviation of atherosclerotic state. Administration of MRBF-3 significantly retained plasma and liver peroxides towards their normal levels, and also, produced significant increase in resistance towards major atherogenic modifications; namely LDL oxidation, LDL aggregation and LDL retention by 44%, 30%, and 33%, respectively. Thus, it can be concluded that the consumption of MRBF-2 and (MRBF-3, in some extent) fractions of M. alba L. root bark 70% alcohol extract may act as a potent hypocholesterolemic nutrient and powerful antioxidant via the inhibition of LDL atherogenic modifications and lipid peroxides formation in hypercholesterolemic rats.