Effect of supplementation of cryoprotectant solution with hydroxypropyl cellulose for vitrification of bovine oocytes.

BACKGROUND: Successful cryopreservation of bovine oocytes is very important for research and commercial applications. However, the survival and development rate of vitrified-thawed (VT) oocytes are lower than those of non-vitrified-thawed (non-VT) oocytes. OBJECTIVE: To investigate the effect of adding hydroxypropyl cellulose (HPC) to the vitrification solution for bovine oocytes. MATERIALS AND METHODS: For vitrification, bovine metaphase II oocytes were pretreated with a solution containing 10% ethylene glycol supplemented with 0, 10, 50, or 100 ug/mL HPC for 5 min, exposed to a solution containing 30% ethylene glycol supplemented with 0, 10, 50, or 100 ug/mL HPC for 30 s, and then directly plunged into liquid nitrogen. RESULTS: The survival rate of oocytes was significantly higher in the 50 HPC group than in the 0, 10, and 100 HPC groups. The reactive oxygen species level was lower in the non-VT and 50 HPC groups than in the other groups. The mRNA levels of proapoptotic genes (Bax) were lower in the non-VT, 0, and 50 HPC groups than in the other groups. The mRNA levels of antiapoptotic genes (BCl2) were higher in the non-VT than in the other groups. The development rates of embryos (day 8) obtained via parthenogenetic activation (PA) were determined in the non-VT, 0 HPC, and 50 HPC groups. The cleavage rate was significantly higher in the non-VT group. CONCLUSION: Supplementation of vitrification solution with HPC improves the survival of VT bovine oocytes and the development capacity of embryos derived from these oocytes via PA. doi.org/10.54680/fr23110110212.

Anti-melanoma, tyrosinase inhibitory and anti-microbial activities of gold nanoparticles synthesized from aqueous leaf extracts of Teraxacum officinale.

There has been a tenacious search for pharmaceuticals of natural origin, as they are cost-effective and are noted for having little or no side effects. The rate at which diseases are developing resistance to synthetic drugs is quite alarming, and the side effects of these drugs remain an excruciating agony to the pharmaceutical industry. Gold nanoparticles (AuNPs) have wide applications in current technology. However, their use in medicine has not been adequately explored. Chemical methods for the synthesis are associated with environmental benignity and tissue toxicity on in vivo administration. For the first time, we have synthesized AuNPs from leaf extracts of Teraxacum officinale that were found to have significant anti-melanoma, tyrosinase inhibitory and anti-microbial effects, and hence stand as promising candidates for use in cosmetics medical and food industries.

Homologous expression and quantitative analysis of T3SS-dependent secretion of TAP-tagged XoAvrBs2 in Xanthomonas oryzae pv. oryzae induced by rice leaf extract.

Xanthomonas oryzae pv. oryzae (Xoo) produces a putative effector, XoAvrBs2. We expressed XoAvrBs2 homologously in Xoo with a TAP-tag at the C-terminus to enable quantitative analysis of protein expression and secretion. Addition of rice leaf extracts from both Xoo-sensitive and Xoo-resistant rice cultivars to the Xoo cells induced expression of the XoAvrBs2 gene at the transcriptional and translational levels, and also stimulated a remarkable amount of XoAvrBs2 secretion into the medium. In a T3SS-defective Xoo mutant strain, secretion of the TAPtagged XoAvrBs2 was blocked. Thus, we elucidated the transcriptional and translational expressions of the XoAvrBs2 gene in Xoo was induced in vitro by the interaction with rice and the induced secretion of XoAvrBs2 was T3SSdependent. It is the first report to measure the homologous expression and secretion of XoAvrBs2 in vitro by rice leaf extract. Our system for the quantitative analysis of effector protein expression and secretion could be generally used for the study of host-pathogen interactions.

Hyperthermia with magnetic nanowires for inactivating living cells.

We describe a method to induce hyperthermia in cells, in-vitro, by remotely heating Ni nanowires (NWs) with radio frequency (RF) electromagnetic fields. Ni NWs were internalized by human embryonic kidney cells (HEK-293). Only cells proximal to NWs or with internalized NWs changed shape on exposure to RF fields indicative of cell death. The cell death occurs as a result of hyperthermia, since the RF field remotely heats the NWs as a result of magnetic hysteresis. This is the first demonstration of hyperthermia induced by NWs; since the NWs have anisotropic and strong magnetic moments, our experiments suggest the possibility of performing hyperthermia at lower field strengths in order to minimize damage to untargeted cells in applications such as the treatment of cancer.

Antiplatelet effects of acidamides isolated from the fruits of Piper longum L.

The inhibitory effects of four acidamides, piperine, pipernonaline, piperoctadecalidine, and piperlongumine, isolated from the fruits of Piper longum L. on washed rabbit platelet aggregation were examined. All of the four tested acidamides showed dose-dependent inhibitory activities on washed rabbit platelet aggregation induced by collagen, arachidonic acid (AA), and platelet-activating factor (PAF), except for that induced by thrombin. Piperlongumine, in particular, showed stronger inhibitory effects than other acidamides to rabbit platelet aggregation induced by collagen, AA and PAF.

Suppression of ochratoxin biosynthesis by naturally occurring alkaloids.

The effects of four alkaloids on the biosynthesis of ochratoxin A (OTA), ochratoxin B (OTB) and citrinin were examined on four OTA-producing aspergilli: Aspergillus auricomus, A. sclerotiorum and two isolates of A. alliaceus. Piperine and piperlongumine, natural alkaloids of Piper longum, significantly inhibited OTA production at 0.001% (w/v) for all aspergilli examined. Piperine and piperlongumine affected the polyketide synthesis step of OTA production and inhibited production of citrinin. Curcumin, a constituent of tumeric, completely inhibited mycelial growth of A. alliaceus isolate 791 at 0.1% (w/v) and decreased OTA production by approximately 70% at 0.01% (w/v). Sesamin, a constituent of sesame oil, inhibited OTA and OTB production by 60 and 45%, respectively, at 0.1% (w/v), showing its effect was on chloroperoxidase and polyketide synthase activity. The potential advantage of these natural products to reduce ochratoxin contamination of agricultural commodities is discussed.

Fumigant toxicity of volatile natural products from Korean spices and medicinal plants towards the rice weevil, Sitophilus oryzae (L).

The fumigant toxicity of various volatile constituents of essential oils extracted from sixteen Korean spices and medicinal plants towards the rice weevil, Sitophilus oryzae L (Coleoptera: Curculionidae), was determined. The most potent toxicity was found in the essential oil from Mentha arvensis L. var piperascens (LC50 = 45.5 microliters litre-1 air). GC-MS analysis of essential oil from M arvensis showed it to be rich in menthol (63.2%), menthone (13.1%) and limonene (1.5%), followed in abundance by beta-pinene (0.7%), alpha-pinene (0.6%) and linalool (0.2%). Treatment of S oryzae with each of these terpenes showed menthone to be most active (LC50 = 12.7 microliters litre-1 air) followed by linalool (LC50 = 39.2 microliters litre-1 air) and alpha-pinene (LC50 = 54.9 microliters litre-1 air). Studies on inhibition of acetylcholinesterase activity of S oryzae showed menthone to have a nine-fold lower inhibitory effect than menthol, despite menthone being 8.1-fold more toxic than menthol to the rice weevil. Different modes of toxicity of these monoterpenes towards S oryzae are discussed.

Free radical scavenging and antioxidant enzyme fortifying activities of extracts from Smilax china root.

The extract from Smilax china root has been used as medicinal remedy and reported to retain antimicrobial and antimutagenic acitivities. In this study, a possible presence of antioxidant activity of Smilax china root extract was investigated. Methanol extract (Me) revealed the presence of high 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity (IC50 7.4 microg/ml) and protective property of cell's viability. Further fractionation with various solvent extraction and assay showed high levels of DPPH free radical scavenging activity in the ethyl acetate, butanol and water extracted fractions. In addition, V79-4 cells treated with Me of Smilax china root induced an increase of superoxide dismutase, catalase and glutathione peroxidase activities in a dose-dependent manner between 4-100 microg/ml. These results suggest that the medicinal component of the root of Smilax china extracts also contains antioxidant activity.

Mosquito larvicidal activity of pipernonaline, a piperidine alkaloid derived from long pepper, Piper longum.

A methanol extract of Piper longum fruit was found to be active against mosquito larvae of Culex pipiens pallens at 10 microg/ml after 24 h. A piperidine alkaloid, pipernonaline, was found to be responsible for this activity, with the 24-h median lethal dose (LD50) value for this compound being 0.21 mg/liter. The LD50 value of pipernonaline was not much higher than those for the 3 organophosphorous insecticides malathion, chlorpyrifos-methyl, and pirimiphos-methyl, used for comparative purpose in this study. Structural elucidation of pipernonaline was by means of mass spectrometry (1H and 13C nuclear magnetic resonance imaging).

Radioprotective effects of two traditional Chinese medicine prescriptions: si-wu-tang and si-jun-zi-tang.

We performed this study to determine the effect of Si-Wu-Tang, a basic prescription of traditional Oriental medicine as a blood-building decoction (Chinese medical concept: Bu-Xie), Si-Jun-Zi-Tang, a basic prescription as an energy tonic (Chinese medical concept: Bu-Qi) and its major ingredients on jejunal crypt survival, endogenous spleen colony formation, and apoptosis in jejunal crypt cells of mice irradiated with high and low dose of gamma-irradiation. Si-Wu-Tang administration before irradiation protected the jejunal crypts (p < 0.0005), increased the formation of endogenous spleen colonies (p < 0.05) and reduced the frequency of radiation-induced apoptosis (p < 0.05). In an experiment on the effect of ingredients of Si-Wu-Tang, the result indicated that extract of Danggui and Baishaoyao might have a major radioprotective effect. The radioprotective effect of Si-Jun-Zi-Tang and its ingredients were not as significant as that of Si-Wu-Tang. Although the mechanisms of this inhibitory effect remain to be elucidated, these results indicate that Si-Wu-Tang might be a useful radioprotector, especially since it is a relatively nontoxic natural product. Further studies are needed to characterize better the protective nature of Si-Wu-Tang extract and its ingredients.

Branched-chain fatty acid requirement for avermectin production by a mutant of Streptomyces avermitilis lacking branched-chain 2-oxo acid dehydrogenase activity.

The eight natural avermectins produced by Streptomyces avermitilis have the carbon skeleton of either isobutyric or S-2-methylbutyric acid incorporated into their structures. A mutant of S. avermitilis has been isolated that contains no functional branched-chain 2-oxo acid dehydrogenase activity. The mutant, in contrast to its parent, is unable to grow with isoleucine, valine and leucine as carbon sources. In medium lacking both S(+)-2-methylbutyric and isobutyric acid, the mutant is also incapable of making the natural avermectins, while supplementation with either one of these compounds restores production of the corresponding four natural avermectins. These facts indicate that in S. avermitilis the branched-chain 2-oxo acid dehydrogenase enzyme functions not only to catabolize the cellular branched-chain amino acids in order to meet energy and growth requirements but also to provide the small branched-chain organic acid precursor molecules necessary for avermectin biosynthesis. Supplementation of the mutant strain with R(-)-2-methylbutyric acid yields novel isomeric avermectins unseen in the (unsupplemented) wild-type strain. It was also concluded that acetate and propionate production by branched-chain 2-oxo acid degradation is not absolutely essential for avermectin production.