Glycosylations of Inosine and Uridine Nucleoside Bases and Synthesis of the New 1-(β-D-Glucopyranosyl)-Inosine-5′, 6″-diphosphate

Abstract

Gluco- and ribosylation of the bases of sugar protected inosine and uridine were investigated, obtaining only adducts with β-configuration at the new glycosidic carbon; stereospecific insertion of a sugar moiety at the 1-N of inosine was achieved either using a Mitsunobu approach (for ribosylation) or by direct coupling of 1-δ-bromoglucose 13 with 2′,3′,5′-tri-O-acetylinosine for glucosylation. 1-(β-D-glucosyl)-inosine, chosen as starting substrate for glucosylated analogs of cyclic IDP-ribose, was phosphorylated at the primary hydroxyls and tested in intramolecular pyrophosphate bond formation.     

Effects of the invasive duckweed Lemna minuta on aquatic animals: evidence from an indoor experiment

Abstract

Since effects of alien invasive free-floating plants can be relevant in aquatic ecosystems, we investigated the non-native Lemna minuta impact on four aquatic animal groups: Hydra vulgaris (Coelenterates), Asellus aquaticus (Arthropods), Gambusia affinis (Fish), Bufo bufo tadpoles (Amphibians). An indoor experiment was conducted keeping animals in water held in tanks with L. minuta mats of 0.5 (WI1), 1.5?cm thick (WI2) and without mats (WOU). Water parameters (DO, DO%, pH) and animal responses (survival rate, vitality) were measured every 48?h (0–288?h). Treatments with mats showed significant impacts on animals which were more severe with increasing mat thickness. Strong decreasing of oxygen and pH associated with mat occurrence had a large impact on animals. In WI2 all individuals died within 144?h (H. vulgaris, B. bufo within 96h), while in WI1 there was a higher survival rate and vitality (excluding B. bufo died within 96?h) and in WOU no deaths. This evidence suggests L. minuta thick mats (≥1.5?cm) could have a high impact on animal biodiversity, especially reducing oxygenation level in aquatic ecosystem.     

Adaptation of fungi,including yeasts,to cold environments

A wide range of cold environments exist, with an equally broad variety of fungi and yeasts that have adapted to such environments. These adaptations, which affect membranes, enzymes and other cellular components, such as radical scavenging molecules, display a great potential for exploitation in biotechnology. Alterations have been detected in membrane lipids, with an increase in fatty acid unsaturated bonds that enhance their fluidity. We report new data on the different phospholipid composition in membrane lipids in the same fungal species from both Antarctic and temperate regions. The decrease in temperature causes intracellular oxidative stress by inducing the generation of reactive oxygen species. We report the results of the first analysis of the non-enzymatic antioxidant response and phenolic compound production by an Antarctic strain of Geomyces pannorum. A survey on yeasts from the cryosphere is reported with a focus on their adaptation to a cold environment. Some studies have shown that the number of macrofungi in glacier forefronts rises as deglaciation increases. The survival success of many plants in such areas may be attributed to their mycorrhizal associations. We highlighted the macrofungal biodiversity of some Italian alpine habitats, in which we Inocybe microfastigiata, Laccaria montana and Lactarius salicis-herbaceae were recorded for the first time in Lombardy (Italy).     

The Entner–Doudoroff pathway empowers Pseudomonas putida KT2440 with a high tolerance to oxidative stress

Glucose catabolism of Pseudomonas putida is carried out exclusively through the Entner–Doudoroff (ED) pathway due to the absence of 6‐phosphofructokinase. In order to activate the Embden–Meyerhof–Parnas (EMP) route we transferred the pfkA gene from Escherichia coli to a P. putida wild‐type strain as well as to an eda mutant, i.e. lacking 2‐keto‐3‐deoxy‐6‐phosphogluconate aldolase. PfkA^{E. coli} failed to redirect the carbon flow from the ED route towards the EMP pathway, suggesting that ED was essential for sugar catabolism. The presence of PfkA^{E. coli} was detrimental for growth, which could be traced to the reduction of ATP and NAD(P)H pools along with alteration of the NAD(P)H/NADP⁺ ratio. Pseudomonas putida cells carrying PfkA^{E. coli} became highly sensitive to diamide and hydrogen peroxide, the response to which is very demanding of NADPH. The inhibitory effect of PfkA^{E. coli} could in part be relieved by methionine, the synthesis of which relies much on NADPH. These results expose the role of the ED pathway for generating the redox currency (NADPH) that is required for counteracting oxidative stress. It is thus likely that environmental bacteria that favour the ED pathway over the EMP pathway do so in order to gear their aerobic metabolism to endure oxidative‐related insults.     

pks+ Escherichia coli more prevalent in benign than malignant colorectal tumors

Molecular Biology Reports - Some E. coli strains that synthesize the toxin colibactin within the 54-kb pks island are being implicated in colorectal cancer (CRC) development. Here, the prevalence...     

"Canis" ferox Revisited: Diet Ecomorphology of Some Long Gone (Late Miocene and Pliocene) Fossil Dogs

Journal of Mammalian Evolution - The late Miocene was a period of great radiation for the subfamily Caninae in North America. During this time, the early taxa of the two tribes of this subfamily,...     

Publisher Correction: Risk screening of the potential invasiveness of non-native aquatic species in Vietnam

Biological Invasions - A correction to this paper has been published: https://doi.org/10.1007/s10530-021-02498-4