Turnover of Phospholipids in an Unsaturated Fatty Acid Auxotroph of Escherichia coli

The membrane phospholipids of an unsaturated fatty acid auxotroph of Escherichia coli were found to undergo turnover. These phospholipids were excreted into the culture medium, and were replaced in the cell with newly synthesized phospholipids. Phospholipids of growing cells supplemented with elaidic acid underwent rapid turnover, while those of cells supplemented with oleate, or cis-vaccenate plus palmitoleate, underwent slow turnover. Starvation for required amino acids stimulated this turnover in the latter two cases. Protein was also lost from growing cells. However, after amino acid starvation this loss ceased while phospholipid turnover continued. Electron micrographs of growing cells indicated that large pieces of membrane-like material were separating from the cell surface.     

Purification and characterization of a bacteriocin from an oenological strain of Leuconostoc mesenteroides subsp. cremoris

Malolactic fermentation (MLF), which improves organoleptic properties and biologic stability of some wines, may cause wine spoilage if uncontrolled. Bacteriocins were reported as efficient preservatives to control MLF through their bactericidal effect on malolactic bacteria. Leuconostoc mesenteroides subsp. cremoris W3 isolated from wine produces an inhibitory substance that is bactericidal against malolactic bacteria in model wine medium. Treatment of the culture supernatant of strain W3 with proteases eliminated the inhibitory activity, which proved that it is a true bacteriocin and we tentatively termed it mesentericin W3. The bacteriocin inhibited the growth of food-borne pathogenic bacteria such as Enterococcus faecalis, Listeria monocytogenes, and malolactic bacteria. It was active over a wide pH range and stable to organic solvents and heat. Mesentericin W3 was purified to homogeneity by a pH-mediated cell adsorption–desorption method, cation exchange, hydrophobic interaction, and reverse-phase chromatography. Matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectroscopy (MS) and partial amino acid sequence analysis revealed that mesentericin W3 was identical to mesentericin Y105.     

Liver and muscle fatty acid composition of mature and immature rainbow trout (<Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>) fed two different diets

Fatty acid composition of liver and muscle tissues of immature and mature Oncorhynchus mykiss fed on two different diets were determined. Fatty acid analyses were carried out by gas chromatography. Palmitic acid (C16:0), oleic acid (C18:1 n-9), linoleic acid (C18:2 n-6) and docosahexaenoic acid (C22:6 n-3) were the major components in both liver and muscle tissues of immature and mature rainbow trout of both sexes. The amounts of C22:6 n-3 were higher in the liver (29.04 ± 0.06 − 27.41 ± 0.17%) and muscle (13.05 ± 0.40 − 11.37 ± 0.21%) of immature fish than in mature fish and depended on the composition of the diet. Results of this study show that fatty acid composition in fish tissues can considerably vary, depending on the age of fish and their diet. Thus more detailed studies are necessary on the influence of diet on immature and mature fish fatty acid composition. The age and diet of fish consumed may also be important for human health.     

Formation of Adeno-Associated Virus Circular Genomes Is Differentially Regulated by Adenovirus E4 ORF6 and E2a Gene Expression

A central feature of the adeno-associated virus (AAV) latent life cycle is persistence in the form of both integrated and episomal genomes. However, the molecular processes associated with episomal long-term persistence of AAV genomes are only poorly understood. To investigate these mechanisms, we have utilized a recombinant AAV (rAAV) shuttle vector to identify circular AAV intermediates from transduced HeLa cells and primary fibroblasts. The unique structural features exhibited by these transduction intermediates included circularized monomer and dimer virus genomes in a head-to-tail array, with associated specific base pair alterations in the 5′ viral D sequence. In HeLa cells, the abundance and stability of AAV circular intermediates were augmented by adenovirus expressing the E2a gene product. In the absence of E2a, adenovirus expressing the E4 open reading frame 6 gene product decreased the abundance of AAV circular intermediates, favoring instead the linear replication form monomer (Rf_m) and dimer (Rf_d) structures. In summary, the formation of AAV circular intermediates appears to represent a new pathway for AAV genome conversion, which is consistent with the head-to-tail concatemerization associated with latent-phase persistence of rAAV. A better understanding of this pathway may increase the utility of rAAV vectors for gene therapy.     

An update comprehensive review on the status of COVID-19: vaccines,drugs, variants and neurological symptoms

Various recently reported mutant variants, candidate and urgently approved current vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), many current situations with severe neurological damage and symptoms as well as respiratory tract disorders have begun to be reported. In particular, drug, vaccine, and neutralizing monoclonal antibodies (mAbs) have been developed and are currently being evaluated in clinical trials. Here, we review lessons learned from the use of novel mutant variants of the COVID-19 virus, immunization, new drug solutions, and antibody therapies for infections. Next, we focus on the B 1.1.7, B 1.351, P.1, and B.1.617 lineages or variants of concern that have been reported worldwide, the new manifestations of neurological manifestations, the current therapeutic drug targets for its treatment, vaccine candidates and their efficacy, implantation of convalescent plasma, and neutralization of mAbs. We review specific clinical questions, including many emerging neurological effects and respiratory tract injuries, as well as new potential biomarkers, new studies in addition to known therapeutics, and chronic diseases of vaccines that have received immediate approval. To answer these questions, further understanding of the burden kinetics of COVID-19 and its correlation with neurological clinical outcomes, endogenous antibody responses to vaccines, pharmacokinetics of neutralizing mAbs, and action against emerging viral mutant variants is needed.     

T-DNA-mediated transfer of Agrobacterium tumefaciens chromosomal DNA into plants

Besides the well-documented integration of DNA flanked by the transfer DNA borders, occasional insertion of fragments from the tumor-inducing plasmid into plant genomes has also been reported during Agrobacterium tumefaciens-mediated transformation. We demonstrate that large (up to approximately 18 kb) gene-bearing fragments of Agrobacterium chromosomal DNA (AchrDNA) can be integrated into Arabidopsis thaliana genomic DNA during transformation. One in every 250 transgenic plants may carry AchrDNA fragments. This has implications for horizontal gene transfer and indicates a need for greater scrutiny of transgenic plants for undesired bacterial DNA.     

Identification of osteopontin phosphorylation sites involved in bone remodeling and inhibition of pathological calcification

Osteopontin is a noncollagenous, phosphorylated extracellular glycoprotein, expressed in mineralized and nonmineralized tissues, organs and body fluids. The protein contains an RGD tripeptide cell-binding motif, and is subjected to a variety of posttranslational modifications that play important roles in its multiple biological functions, such as bone remodeling and inhibition of pathological calcification. In this study, we have expressed bovine osteopontin in a prokaryotic system and identified the seven amino acid residues phosphorylated in vitro by CKII.     

Sequence structure of hidden 10.4-base repeat in the nucleosomes of C. elegans

By measuring prevailing distances between YY, YR, RR, and RY dinucleotides in the large database of the nucleosome DNA fragments from C. elegans, the consensus sequence structure of the nucleosome DNA repeat of C. elegans was reconstructed: (YYYYYRRRRR)n. An actual period was estimated to be 10.4 bases. The pattern is fully consistent with the nucleosome DNA patterns of other eukaryotes, as established earlier, and, thus, the YYYYYRRRRR repeat can be considered as consensus nucleosome DNA sequence repeat across eukaryotic species. Similar distance analysis for [A, T] dinucleotides suggested the related pattern (TTTYTARAAA)n where the TT and AA dinucleotides display rather out of phase behavior, contrary to the "AA or TT" in-phase periodicity, considered in some publications. A weak 5-base periodicity in the distribution of TA dinucleotides was detected.