Common subtropical and tropical nonpollen food sources of the boll weevil (Coleoptera: Curculionidae)

It is known that substantial boll weevil, Anthonomus grandis grandis Boheman, individuals can survive mild subtropical winters in some habitats, such as citrus orchards. Our study shows that endocarp of the fruit from prickly pear cactus, Opuntia engelmannii Salm-Dyck ex. Engel.; orange, Citrus sinensis L. Osbeck.; and grapefruit, Citrus paradisi Macfad., can sustain newly emerged adult boll weevils for >5 mo, which is the duration of the cotton-free season in the subtropical Lower Rio Grande Valley of Texas and other cotton-growing areas in the Western Hemisphere. Cotton, Gossypium hirsutum L., and the boll weevil occur in the same areas with one or all three plant species (or other citrus and Opuntia species that might also nourish boll weevils) from south Texas to Argentina. Although adult boll weevils did not produce eggs when fed exclusively on the endocarps of prickly pear, orange, or grapefruit, these plants make it possible for boll weevils to survive from one cotton growing season to the next, which could pose challenges to eradication efforts.     

Acetylation of conserved lysines fine-tunes mitochondrial malate dehydrogenase activity in land plants

Plants need to rapidly and flexibly adjust their metabolism to changes of their immediate environment. Since this necessity results from the sessile lifestyle of land plants, key mechanisms for orchestrating central metabolic acclimation are likely to have evolved early. Here, we explore the role of lysine acetylation as a post-translational modification to directly modulate metabolic function. We generated a lysine acetylome of the moss Physcomitrium patens and identified 638 lysine acetylation sites, mostly found in mitochondrial and plastidial proteins. A comparison with available angiosperm data pinpointed lysine acetylation as a conserved regulatory strategy in land plants. Focusing on mitochondrial central metabolism, we functionally analyzed acetylation of mitochondrial malate dehydrogenase (mMDH), which acts as a hub of plant metabolic flexibility. In P. patens mMDH1, we detected a single acetylated lysine located next to one of the four acetylation sites detected in Arabidopsis thaliana mMDH1. We assessed the kinetic behavior of recombinant A. thaliana and P. patens mMDH1 with site-specifically incorporated acetyl-lysines. Acetylation of A. thaliana mMDH1 at K169, K170, and K334 decreases its oxaloacetate reduction activity, while acetylation of P. patens mMDH1 at K172 increases this activity. We found modulation of the malate oxidation activity only in A. thaliana mMDH1, where acetylation of K334 strongly activated it. Comparative homology modeling of MDH proteins revealed that evolutionarily conserved lysines serve as hotspots of acetylation. Our combined analyses indicate lysine acetylation as a common strategy to fine-tune the activity of central metabolic enzymes with likely impact on plant acclimation capacity.     

A study of structure–activity relationship and anion-controlled quinolinyl Ag(I) complexes as antimicrobial and antioxidant agents as well as their interaction with macromolecules

BioMetals - In this communication, we feature the synthesis and in-depth characterization of a series of silver(I) complexes obtained from the complexation of quinolin-4-yl Schiff base ligands...     

Unravelling Intratumoral Heterogeneity through High-Sensitivity Single-Cell Mutational Analysis and Parallel RNA Sequencing

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Production of nanocellulose by enzymatic hydrolysis: Trends and challenges

There is a great interest in increasing the levels of production of nanocellulose, either by adjusting production systems or by improving the raw material. Despite all the advantages and applications, nanocellulose still has a high cost compared to common fibers and to reverse this scenario the development of new, cheaper, and more efficient means of production is required. The market trend is to have an increase in the mass production of nanocellulose; there is a great expectation of world trade. In this sense, research in this sector is on the rise, because once the cost is not an obstacle to production, this material will have more and more market. Production of the cellulose fibers is determinant for the production of nanocellulose by a hydrolyzing agent with a reasonable yield. This work presents several aspects of this new material, mainly addressing the enzymatic pathway, presenting the hydrolysis conditions such as pH, biomass concentration, enzymatic loading, temperature, and time. Also, the commonly used characterization methods are presented, as well as aspects of the nanocellulose production market.     

Site specific replacements of a single loop nucleoside with a dibenzyl linker may switch the activity of TBA from anticoagulant to antiproliferative

Many antiproliferative G-quadruplexes (G4s) arise from the folding of GT-rich strands. Among these, the Thrombin Binding Aptamer (TBA), as a rare example, adopts a monomolecular well-defined G4 structure. Nevertheless, the potential anticancer properties of TBA are severely hampered by its anticoagulant action and, consequently, no related studies have appeared so far in the literature. We wish to report here that suitable chemical modifications in the TBA sequence can preserve its antiproliferative over anticoagulant activity. Particularly, we replaced one residue of the TT or TGT loops with a dibenzyl linker to develop seven new quadruplex-forming TBA based sequences (TBA-bs), which were studied for their structural (CD, CD melting, 1D NMR) and biological (fibrinogen, PT and MTT assays) properties. The three-dimensional structures of the TBA-bs modified at T13 (TBA-bs13) or T12 (TBA-bs12), the former endowed with selective antiproliferative activity, and the latter acting as potently as TBA in both coagulation and MTT assays, were further studied by 2D NMR restrained molecular mechanics. The comparative structural analyses indicated that neither the stability, nor the topology of the G4s, but the different localization of the two benzene rings of the linker was responsible for the loss of the antithrombin activity for TBA-bs13.