Arabidopsis ADC1 functions as an N~δ-acetylornithine decarboxylase

Polyamines are small aliphatic amines found in almost all organisms, ranging from bacteria to plants and animals. In most plants, putrescine, the metabolic precursor for longer polyamines, such as spermidine and spermine, is produced from arginine, with either agmatine or ornithine as intermediates. Here we show that Arabidopsis thaliana(Arabidopsis) arginine decarboxylase 1(ADC1), one of the two known arginine decarboxylases in Arabidopsis, not only synthesizes agmatine from arginine, but also converts N~δ-acetylornithine to N-acetylputrescine. Phylogenetic analyses indicate that duplication and neofunctionalization of ADC1 and NATA1, the enzymes that synthesize N~δ-acetylornithine in Arabidopsis, co-occur in a small number of related species in the Brassicaceae. Unlike ADC2, which is localized in the chloroplasts, ADC1 is in the endoplasmic reticulum together with NATA1, an indication that these two enzymes have access to the same substrate pool. Together, these results are consistent with a model whereby NATA1 and ADC1 together provide a pathway for the synthesis of N-acetylputrescine in Arabidopsis.     

Five-in-One: Simultaneous isolation of multiple major liver cell types from livers of normal and NASH mice

NASH is a chronic liver disease that affects 3%–6% of individuals and requires urgent therapeutic developments. Isolating the key cell types in the liver is a necessary step towards understanding their function and roles in disease pathogenesis. However, traditional isolation methods through gradient centrifugation can only collect one or a few cell types simultaneously and pose technical difficulties when applied to NASH livers. Taking advantage of identified cell surface markers from liver single-cell RNAseq, here we established the combination of gradient centrifugation and antibody-based cell sorting techniques to isolate five key liver cell types (hepatocytes, endothelial cells, stellate cells, macrophages and other immune cells) from a single mouse liver. This method yielded high purity of each cell type from healthy and NASH livers. Our five-in-one protocol simultaneously isolates key liver cell types with high purity under normal and NASH conditions, enabling for systematic and accurate exploratory experiments such as RNA sequencing.     

Moringa oleifera leaf fractions attenuated Naje haje venom-induced cellular dysfunctions via modulation of Nrf2 and inflammatory signalling pathways in rats

Naja haje envenoming could activate multiple pathways linked to haematotoxic, neurological, and antioxidant systems dysfunctions. Moringa oleifera has been used in the management of different snake venom-induced toxicities, but there is no scientific information on its antivenom effects against Naja haje. This study thus, investigated the antivenom activities of different extract partitions of M. oleifera leaves against N. haje envenoming. Forty five male rats were divided into nine groups (n = 5). Groups 2 to 9 were envenomed with 0.025 mg/kg (LD₅₀) of N. haje venom while group 1 was given saline. Group 2 was left untreated, while group 3 was treated with polyvalent antivenom, groups 4, 6 and 8 were treated with 300 mg/kg^?1 of N-hexane, ethylacetate and ethanol partitions of M. oleifera, respectively. Groups 5, 7 and 9 were also treated with 600 mgkg^?1of the partitions, respectively. Ethanol extract and ethyl acetate partition of M. oleifera significantly improved haematological indices following acute anaemia induced by the venom. Likewise, haemorrhagic, haemolytic and anti-coagulant activities of N. haje venom were best inhibited by ethanol partition. Envenoming significantly down-regulated Nuclear factor erythroid 2-related factor 2 (Nrf2) with the consequent elevation of antioxidant enzymes activities in the serum and brain. Treatment with extract partitions however, elevated Nrf2 levels while normalising antioxidant enzyme activities. Furthermore, there were reduction in levels of pro-inflammatory cytokines (TNF-α and interleukin-1β) in tissues of treated envenomed rats. This study concludes that ethanol partition of M. oleifera was most effective against N. haje venom and could be considered as a potential source for antivenom metabolites.     

A time course study on dose-response relationship between alcohol exposure and its effects on lipid profile and biomarkers of tissue damage

This present research investigated variations in lipid profiles and important biomarkers of tissue damage in response to graded concentrations of alcohol administration in male Wistar rats. Group A (control) received distilled water while group B, C and D received 30%, 40% and 50% (v/v) alcohol respectively. Five rats each from groups A-D were sacrificed after day(s) 1, 7, 14, 21 and 28 of administration. A significant increase was observed at day 28 for serum cholesterol by 79% (group B), 78% (group C) and 47% (group D) together with serum phospholipid 58% (group B), 50% (group C) and 92% (group D). Serum triacylglycerol increased by 71% (group B), 43% (group C) and 16% (group D) at day 21, while concentration of serum albumin decreased at day 28 by 40.9% (group B), 50.2% (group C), 53.3% (group D) respectively when compared with control (group A). Serum aminotransferases and alkaline phosphatase specific activities, as well as creatinine and uric acid concentration increased in a concentration-dependent manner, following alcohol administration. Though most of these effects induced by alcohol were time- and concentration-dependent, 40% alcohol appear to be more stable, giving results consistent with alcohol-induced damages, with minimal mortality. This study therefore further validated dyslipidemia and imbalance in clinical biomarkers as hallmarks of tissue damage induced by excessive alcohol consumption with an insight on the time- and concentration-response relationship between alcohol consumption and its toxicity.     

In vitro effect of fermented maize slurry and ethanol extracts of five plants against Sclerotium rolfsii Sacc. of tomato (Lycopersicon esculentum Mill.)

Sclerotium rolfsii Sacc. is an important fungal pathogen affecting the production of tomato (Lycopersicon esculentum Mill.). Conventional control methods using chemicals are expensive, which constitute environmental hazards. This has necessitated the search for alternatives in botanicals. Ethanol and supernatant solution of fermented maize slurry extracts from Ocimum gratissimum, Cymbopogon citratus, Xylopia aethiopica, Aframomum melegueta and Allium sativum were evaluated. In vitro test was carried out at 1, 2, 3, 4 and 5% concentrations against the pathogen. Mycelial growth was significantly reduced in the following descending order: O. gratissimum?>?A. melegueta?>?A. sativum?>?X. aethiopica?>?C. citratus. Supernatant solution extracts of O. gratissimum and A. melegueta at 5% concentration gave highest mycelial reduction (0.00?mm), respectively, while O. gratissimum ethanol extract recorded highest mycelial reduction (0.23?mm) among the ethanol extracts. Supernatant solution of fermented maize slurry extracts of O. gratissimum and A. melegueta at 5% concentration was more effective in reducing mycelial growth of S. rolfsii.     

Sesquiterpenes of the liverwort Scapania undulata

The essential oil of the liverwort Scapania undulata, collected in the Harz mountains, Northern Germany, was analysed by gas chromatography (GC), GC-mass spectrometry (MS) and several new components were isolated and investigated by various NMR techniques. As new natural compounds the sesquiterpene hydrocarbons (+)-helminthogermacrene (1) [the 4Z-isomer of germacrene A (9)], (-)-cis-beta-elemene (2) as a Cope-rearrangement product of 1, (+)-beta-isolongibornene (3) and (-)-perfora-1,7-diene (4) could be identified. 1 has an identical mass spectrum and identical GC retention time on a non-polar stationary phase as germacrene A (9) but is considerably more stable than the latter. The Cope-rearrangement of 1 proceeds slowly at 350 degrees C and (-)-cis-beta-elemene (2) is formed together with small amounts of other diastereoisomers.     

Accumulation of the proteolytic marker peptide ubiquitin in the trophoblast of mammalian blastocysts

Ubiquitination is a universal protein degradation pathway in which the molecules of 8.5-kDa proteolytic peptide ubiquitin are covalently attached to the epsilon-amino group of the substrate's lysine residues. Little is known about the importance of this highly conserved mechanism for protein recycling in mammalian gametogenesis and fertilization. The data obtained by the students and faculty of the international training course Window to the Zygote 2000 demonstrate the accumulation of ubiquitin-cross-reactive structures in the trophoblast, but not in the inner cell mass of the expanding bovine and mouse blastocysts. This observation suggests that a major burst of ubiquitin-dependent proteolysis occurs in the trophoblast of mammalian peri-implantation embryos. This event may be important for the success of blastocyst hatching, differentiation of embryonic stem cells into soma and germ line, and/or implantation in both naturally conceived and reconstructed mammalian embryos.     

Reinvestigation of the iodocyclization of 4,5,7-tri-O-benzyl-3-(N-benzylacetamido)-1,2,3-trideoxy-D-gluco-hept-1-enitol: unexpected formation of a 1,3-imino-heptitol derivative

The NIS-mediated iodocyclization of 4,5,7-tri-O-benzyl-3-(N-benzylacetamido)-1,2,3-trideoxy-D-gluco-hept-1-enitol gave unexpectedly a 1,3-imino-heptitol derivative, namely 2-O-acetyl-N-benzyl-4,5,7-tri-O-benzyl-1,3-dideoxy-1,3-imino-D-glycero-D-ido-heptitol. This compound is a new example of a rare class of azetidine imino alditol derivatives which have interesting properties such as glycosidase inhibitors. The physical and spectral data for this imino heptitol were essentially identical to those reported for 2,6-anhydro-4,5,7-tri-O-benzyl-3-(N-benzylacetamido)-3-deoxy-D-glycero-D-ido-heptitol, a derivative of C-(2-acetamido-2-deoxy-alpha-D-glucopyranosyl)methanol obtained from the same precursor [Lay, L.; Nicotra, F.; Panza, L.; Verani, A. Gazz. Chim. Ital. 1992, 122, 345-348]; these findings cast doubts on the structure reported for the latter product.     

Bioactive compounds from Rumex plants

Two new naphthalene acylglucosides, rumexneposides A (1) and B (2), together with 12 known compounds (3-14), were isolated from the roots of Rumex nepalensis. Their structures were established by chemical and spectroscopic methods. The biological activities of compounds 1-14 as well as an additional 11 compounds previously isolated from R. nepalensis and Rumex hastatus (15–25) were evaluated against Mycobacterium tuberculosis, para-aminobenzoic acid (pAba) pathway, and a panel of human cancer cell lines. The results showed that compound 15 was the most active against M. tuberculosis with an MIC value of 2.85 μM similar to that of isoniazid. Compound 5 could inhibit pAba synthetic pathway with an MIC value of 12.6 μM, comparable to that of positive control abyssomicin C, representing a new example of the rare pAba pathway inhibitors.