Correlation of ovary and leaf spermidine and spermine content with the alternate bearing habit of olive

In order to investigate the possible role of the polyamines spermidine and spermine, in the alternate bearing habit of the olive, a comparative analysis of their content in vegetative and reproductive organs during the flowering period of the 'on' and 'off' years, was conducted. Samples of flowers, ovaries and leaves from two cultivars, the biennial bearer 'Chondrolia Chalkidikis' and the regular cropping 'Koroneiki' were used and the free and conjugated forms of polyamines were detected. In addition, the concentrations of K(+) and Ca(2+) were determined in all samples. Spermidine conjugates were predominant in all samples, while free spermine was not detectable. Conjugated forms of both spermidine and spermine were accumulated in ovaries, rather than in other floral tissues (corolla and stamens). They also, accumulated in significantly higher concentrations in ovaries and leaves of both cultivars, during the 'on' compared with the 'off' year, and in much higher concentrations, during the 'on' year, in ovaries of the strong alternate bearer 'Chondrolia Chalkidikis' than in 'Koroneiki'. Free spermidine was detected in ovaries and leaves of both cultivars, showing a decline during ovule fertilization in both years. Such a decline was not always recorded for the conjugated forms, depending on the organ studied and the flower load. A relation between endogenous spermidine and spermine with the K(+) or Ca(2+) composition was not established.     

Mutation of amino acids in the alpha 1,3-fucosyltransferase motif affects enzyme activity and Km for donor and acceptor substrates

Alpha 1,3-fucosyltransferases (FucT) share a conserved amino acid sequence designated the alpha 1,3 FucT motif that has been proposed to be important for nucleotide sugar binding. To evaluate the importance of the amino acids in this motif, each of the alpha 1,3 FucT motif amino acids was replaced with alanine (alanine scanning mutagenesis) in human FucT VI, and the resulting mutant proteins were analyzed for enzyme activity and kinetically characterized in those cases in which the mutant protein had sufficient activity. Two of the mutant proteins were inactive, six had less than 1% of wild-type activity, and four had approximately 10-50% of wild-type enzyme activity. Three of the mutant proteins with significant enzyme activity had substantially larger Km (5 to 15 times) for GDP-fucose than FucT VI wild-type enzyme. The fourth mutant protein with significant enzyme activity (S249A) had a Km at least 10 times larger than wild-type FucT VI for the acceptor substrate, with only a slightly larger (2-3 times) Km for GDP-fucose. Thus mutation of any of the amino acids within the alpha 1,3 FucT motif to Ala affects alpha 1,3-FucT activity, and substitution of Ala for some of the alpha 1,3 FucT motif amino acids results in proteins with altered kinetic constants for both the acceptor and donor substrates. Secondary structure prediction suggests a helix-loop-helix fold for the alpha 1,3 FucT motif, which can be used to rationalize the effects of mutations in terms of 3D structure.     

Vascular endothelial growth factor and placenta growth factor in intrauterine growth-restricted fetuses and neonates

The angiogenic factors vascular endothelial growth factor (VEGF) and placenta growth factor (PlGF) are respectively up- and downregulated by hypoxia. We aimed to study circulating levels of the above factors in intrauterine growth restriction (IUGR) and to correlate their levels with the customized centiles of the infants. The study included 25 IUGR and 25 appropriate for gestational age (AGA) full-term, singleton infants and their mothers. Maternal (MS), fetal (UC), and neonatal day 1 (N1) and 4 (N4) blood was examined. MS and N1 PlGF, as well as UC VEGF levels correlated with the customized centiles of the infants (r= 0.39, P=.007, r=0.34, P=.01, and r= -0.41, P=.004, resp). Furthermore, UC, N1, and N4 VEGF levels were higher in girls (r=0.36, P=.01, r=0.33, P=.02, and r=0.41, P=.005 resp). In conclusion, positive and negative correlations of examined factors with the customized centiles of the infant could rely on placental function and intrauterine oxygen concentrations-both being usually lower in IUGR cases-while higher VEGF levels in girls should possibly be attributed to the stimulating action of estrogens.     

Effects of Pseudomonas putida modified to produce phenazine-1-carboxylic acid and 2,4-diacetylphloroglucinol on the microflora of field grown wheat

Pseudomonas putida WCS358r, genetically modified to have improved activity against soil-borne pathogens, was released into the rhizosphere of wheat. Two genetically modified derivatives carried the phzor the phl biosynthetic gene loci and constitutively produced either the antifungal compound phenazine-1-carboxylic acid (PCA) or the antifungal and antibacterial compound 2,4-diacetylphloroglucinol (DAPG). In 1997 and 1998, effects of single introductions of PCA producing derivatives on the indigenous microflora were studied. A transient shift in the composition of the total fungal microflora, determined by amplified ribosomal DNA restiction analysis (ARDRA), was detected. Starting in 1999, effects of repeated introduction of genetically modified microorganisms (GMMs) were studied. Wheat seeds coated with the PCA producer, the DAPG producer, a mixture of the PCA and DAPG producers, or WCS358r, were sown and the densities, composition and activities of the rhizosphere microbial populations were measured. All introduced strains decreased from 10⁷CFU per gram of rhizosphere sample to below the detection limit after harvest of the wheat plants. The phz genes were stably maintained in the PCA producers, and PCA was detected in rhizosphere extracts of plants treated with this strain or with the mixture of the PCA and DAPG producers. The phl genes were also stably maintained in the DAPG producing derivative of WCS358r. Effects of the genetically modified bacteria on the rhizosphere fungi and bacteria were analyzed by using amplified ribosomal DNA restriction analysis. Introduction of the genetically modified bacterial strains caused a transient change in the composition of the rhizosphere microflora. However, introduction of the GMMs did not affect the several soil microbial activities that were investigated in this study. This revised version was published online in August 2006 with corrections to the Cover Date.     

Compliance with Once-Daily versus Twice or Thrice-Daily Administration of Antibiotic Regimens: A Meta-Analysis of Randomized Controlled Trials

Objective

To investigate whether compliance of patients to antibiotic treatment is better when antibiotics are administered once than multiple times daily.

Methods

We performed a systematic search in PubMed and Scopus databases. Only randomized controlled trials were considered eligible for inclusion. Compliance to antibiotic treatment was the outcome of the meta-analysis.

Results

Twenty-six studies including 8246 patients with upper respiratory tract infections in the vast majority met the inclusion criteria. In total, higher compliance was found among patients treated with once-daily treatment than those receiving treatment twice, thrice or four times daily [5011 patients, RR=1.22 (95% CI, 1.11, 1.34]. Adults receiving an antibiotic once-daily were more compliant than those receiving the same antibiotic multiple times daily [380 patients, RR=1.09 (95% CI, 1.02, 1.16)]. Likewise, children that received an antibiotic twice-daily were more compliant than those receiving the same antibiotic thrice-daily [2118 patients, RR=1.10 (95% CI, 1.02, 1.19)]. Higher compliance was also found among patients receiving an antibiotic once compared to those receiving an antibiotic of different class thrice or four times daily [395 patients, RR=1.20 (95% CI, 1.12, 1.28)]. The finding of better compliance with lower frequency daily was consistent regardless of the study design, and treatment duration.

Conclusion

This meta-analysis showed that compliance to antibiotic treatment might be associated with higher when an antibiotic is administered once than multiple times daily for the treatment of specific infections and for specific classes of antibiotics.     

Adaptation to the Interferon-Induced Antiviral State by Human and Simian Immunodeficiency Viruses

The production of type I interferon (IFN) is an early host response to different infectious agents leading to the induction of hundreds of IFN-stimulated genes (ISGs). The roles of many ISGs in host defense are unknown, but their expression results in the induction of an “antiviral state” that inhibits the replication of many viruses. Here we show that prototype primate lentiviruses human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus of macaques (SIV_MAC and SIV_MNE) can replicate in lymphocytes from their usual hosts (humans and macaques, respectively), even when an antiviral state is induced by IFN-α treatment. In contrast, HIV-1 and SIV_MAC/SIV_MNE replication was hypersensitive to IFN-α in lymphocytes from unnatural hosts, indicating that the antiviral state can effectively curtail the replication of primate lentiviruses in hosts to which they are not adapted. Most of the members of a panel of naturally occurring HIV-1 and HIV-2 strains behaved like prototype strains and were comparatively insensitive to IFN-α in human lymphocytes. Using chimeric viruses engineered to overcome restriction factors whose antiretroviral specificities vary in a species-dependent manner, we demonstrate that differential HIV-1 and SIV_MAC sensitivities to IFN-α in lymphocytes from humans and macaques could not be ascribed to TRIM5, APOBEC3, tetherin, or SAMHD1. Single-cycle infection experiments indicated that at least part of this species-specific, IFN-α-induced restriction of primate lentivirus replication occurs early in the retroviral life cycle. Overall, these studies indicate the existence of undiscovered, IFN-α-inducible antiretroviral factors whose spectrum of activity varies in a species-dependent manner and to which at least some HIV/SIV strains have become adapted in their usual hosts.     

SARS‐CoV‐2 nucleocapsid protein phase‐separates with RNA and with human hnRNPs

Tightly packed complexes of nucleocapsid protein and genomic RNA form the core of viruses and assemble within viral factories, dynamic compartments formed within the host cells associated with human stress granules. Here, we test the possibility that the multivalent RNA‐binding nucleocapsid protein (N) from severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) condenses with RNA via liquid–liquid phase separation (LLPS) and that N protein can be recruited in phase‐separated forms of human RNA‐binding proteins associated with SG formation. Robust LLPS with RNA requires two intrinsically disordered regions (IDRs), the N‐terminal IDR and central‐linker IDR, as well as the folded C‐terminal oligomerization domain, while the folded N‐terminal domain and the C‐terminal IDR are not required. N protein phase separation is induced by addition of non‐specific RNA. In addition, N partitions in vitro into phase‐separated forms of full‐length human hnRNPs (TDP‐43, FUS, hnRNPA2) and their low‐complexity domains (LCs). These results provide a potential mechanism for the role of N in SARS‐CoV‐2 viral genome packing and in host‐protein co‐opting necessary for viral replication and infectivity.     

Lipid metabolism and osteoarthritis: lessons from atherosclerosis

Osteoarthritis (OA) is an age-related degenerative disease comprising the main reason of handicap in the Western world. Interestingly, to date, there are neither available biomarkers for early diagnosis of the disease nor any effective therapy other than symptomatic treatment and joint replacement surgery. OA has long been associated with obesity, mainly due to mechanical overload exerted on the joints. Recent studies however, point to the direction that OA is a metabolic disease, as it also involves non-weight bearing joints. In fact, altered lipid metabolism may be the underlying cause. First, adipokines have been shown to be key regulators of OA pathogenesis. Second, epidemiological studies have shown serum cholesterol to be a risk factor for OA development. Third, lipid deposition in the joint is observed at the early stages of OA before the occurrence of histological changes. Fourth, proteomic analyses have shown an important connection between OA and lipid metabolism. Finally, recent gene expression studies reveal a deregulation of cholesterol influx and efflux and in the expression of lipid metabolism-related genes. Interestingly, lipids and lipid metabolism are known to be implicated in the development and progression of another age-related degenerative disease, atherosclerosis (ATH). Thus, although it is tempting to speculate that the osteoarthritic chondrocyte has been transformed to foam cell, it has not been proven yet. However, this may be an intriguing theory linking ATH and OA, which may open new avenues to novel therapeutic interventions for OA taking advantage of previous knowledge from ATH.