Fluorescence methods (VistaCam iX proof and DIAGNODent pen) for the detection of occlusal carious lesions in teeth recovered from archaeological context

Diagnosis of occlusal enamel caries in archaeologically derived collections remains a controversial problem because the accumulation of contaminants in fissures can interfere with diagnosis. Certain novel light‐induced fluorescence methods, such as the DIAGNODent pen 2190 (DD) and VistaCam iX Proof (VC), have been used to detect dental caries in clinical settings. In this study, the abilities of DD and VC to detect initial enamel caries in archaeologically derived material is determined and compared with those of other methods (visual inspection, X‐ray, histology, and micro‐CT). Dental material encompassing the remains of 58 individuals, including a total of 380 teeth from each of three historical periods: modern Islamic (AD 1850–1950), Islamic (AD 600–1200) and late Roman (AD 200–400), obtained from two archaeological sites (Terqa and Tell Masaikh) located in the Middle Euphrates valley (Syria), were analyzed. VC was found to have excellent sensitivity (98), while DD obtained lower sensitivity (76) in detecting dental caries in its early stages. The results obtained by VC and micro‐CT, considered the most reliable imaging technique, were not statistically significant (P = 0.3068). By contrast, results obtained by DD and micro‐CT results, and DD and VC results were statistically significant (P < 0.0001, P = 0.0015, respectively). However the presence of dirt, stain, calculus, and plaque in the pits and fissures of the occlusal surface compromise correct diagnosis of caries by VC and DD. Consequently, for teeth recovered from archaeological contexts where staining, calculus and plaque are present, the best solution remains micro‐CT. Am J Phys Anthropol 154:525–534, 2014. © 2014 Wiley Periodicals, Inc.     

Two fluorogenic substrates for purine nucleoside phosphorylase,selective for mammalian and bacterial forms of the enzyme

Two nontypical nucleosides, 7-β-d-ribosyl-2,6-diamino-8-azapurine and 8-β-d-ribosyl-2,6-diamino-8-azapurine, have been found to exhibit moderately good, and selective, substrate properties toward calf and bacterial (Escherichia coli) forms of purine nucleoside phosphorylase (PNP). The former compound is effectively phosphorolysed by calf PNP and the latter by PNP from E. coli. Both compounds are fluorescent with λ_max ∼ 425 to 430 nm, but the reaction product, 2,6-diamino-8-azapurine, emits in a different spectral region (λ_max ∼ 363 nm) with nearly 40% yield, providing a strong fluorogenic effect at 350 to 360 nm.     

SELECTION FOR ALTERNATIVE MALE REPRODUCTIVE TACTICS ALTERS INTRALOCUS SEXUAL CONFLICT

Intralocus sexual conflict (IASC) arises when fitness optima for a shared trait differ between the sexes; such conflict may help maintain genetic variation within populations. Sex‐limited expression of sexually antagonistic traits may help resolve the conflict, but the extent of this resolution remains a subject of debate. In species with alternative male reproductive tactics, unresolved conflict should manifest more in a more sexually dimorphic male phenotype. We tested this prediction in the bulb mite (Rhizoglyphus robini), a species in which aggressive fighters coexist with benign scramblers. To do this, we established replicated lines in which we increased the proportion of each of the alternative male morphs using artificial selection. After approximately 40 generations, the proportion of fighters and scramblers stabilized at >0.9 in fighter‐ and scrambler‐selected lines, respectively. We then measured several female fitness components. As predicted by IASC theory, female fecundity and longevity were lower in lines selected for fighters and higher in lines selected for scramblers. This finding indicates that sexually selected phenotypes are associated with an ontogenetic conflict that is not easily resolved. Furthermore, we suggest that IASC may be an important mechanism contributing to the maintenance of genetic variation in the expression of alternative reproductive tactics.     

The age-dependent epigenetic and physiological changes in an Arabidopsis T87 cell suspension culture during long-term cultivation

Plant cell suspension cultures represent good model systems applicable for both basic research and biotechnological purposes. Nevertheless, it is widely known that a prolonged in vitro cultivation of plant cells is associated with genetic and epigenetic instabilities, which may limit the usefulness of plant lines. In this study, the age-dependent epigenetic and physiological changes in an asynchronous Arabidopsis T87 cell culture were examined. A prolonged cultivation period was found to be correlated with a decrease in the proliferation rate and a simultaneous increase in the expression of senescence-associated genes, indicating that the aging process started at the late growth phase of the culture. In addition, increases in the heterochromatin-specific epigenetic markers, i.e., global DNA methylation, H3K9 dimethylation, and H3K27 trimethylation, were observed, suggesting the onset of chromatin condensation, a hallmark of the early stages of plant senescence. Although the number of live cells decreased with an increase in the age of the culture, the remaining viable cells retained a high potential to efficiently perform photosynthesis and did not exhibit any symptoms of photosystem II damage.     

Up-regulation of stearoyl-CoA desaturase 1 and elongase 6 genes expression in rat lipogenic tissues by chronic food restriction and chronic food restriction/refeeding

Successful treatment of obesity and related diseases by chronic food restriction requires the understanding of the effect of such nutritional therapy on the expression of genes which have been implicated to be involved in some diseases associated with obesity. The purpose of this study was to examine the effect of chronic food restriction and chronic food restriction/refeeding on lipogenic enzymes, especially the expression of genes encoding the stearoyl-CoA desaturase 1 (Scd1) and elongase6 (Elovl6) in rat liver and adipose tissue. We found that both chronic food restriction and chronic food restriction/refeeding caused increased expression of the Scd1 and Elovl6 genes in both the liver and adipose tissue. The increase was more pronounced in case of chronic food restriction/refeeding (several-fold increase) than that in chronic food restriction alone (two to threefold increase). Essentially, similar results were obtained when the expression of fatty acid synthase, acetyl-CoA carboxylase, ATP-citrate lyase, and malic enzyme genes was studied. Moreover, we found that chronic food restriction and short-term fasting exert opposite effects on the expression of lipogenic enzymes genes. The increased expression of the genes encoding Scd1, Elovl6, and other key lipogenic enzymes may favor fat storage after chronic food restriction/refeeding and may be part of the molecular mechanism by which food restriction/refeeding increases body weight and enhances susceptibility to insulin resistance.     

Convenient synthesis of a propargylated cyclic (3'-5') diguanylic acid and its "click" conjugation to a biotinylated azide

The ribonucleoside building block, N2-isobutyryl-2'-O-propargyl-3'-O-levulinyl guanosine, was prepared from commercial N2-isobutyryl-5'-O-(4,4'-dimethoxytrityl)-2'-O-propargyl guanosine in a yield of 91%. The propargylated guanylyl(3'-5')guanosine phosphotriester was synthesized from the reaction of N2-isobutyryl-2'-O-propargyl-3'-O-levulinyl guanosine with N2-isobutyryl-5'-O-(4,4'-dimethoxytrityl)-2'-O-tert-butyldimethylsilyl-3'-O-[(2-cyanoethyl)-N,N-diisopropylaminophosphinyl] guanosine and isolated in a yield of 88% after P(III) oxidation, 3'-/5'-deprotection, and purification. The propargylated guanylyl(3'-5')guanosine phosphotriester was phosphitylated using 2-cyanoethyl tetraisopropylphosphordiamidite and 1H-tetrazole and was followed by an in situ intramolecular cyclization to give a propargylated c-di-GMP triester, which was isolated in a yield of 40% after P(III) oxidation and purification. Complete N-deacylation of the guanine bases and removal of the 2-cyanoethyl phosphate protecting groups from the propargylated c-di-GMP triester were performed by treatment with aqueous ammonia at ambient temperature. The final 2'-desilylation reaction was effected by exposure to triethylammonium trihydrofluoride affording the desired propargylated c-di-GMP diester, the purity of which exceeded 95%. Biotinylation of the propargylated c-di-GMP diester was easily accomplished through its cycloaddition reaction with a biotinylated azide derivative under click conditions to produce the biotinylated c-di-GMP conjugate of interest in an isolated yield of 62%.     

Cadmium and copper toxicity to tench <Emphasis Type="Italic">Tinca</Emphasis><Emphasis Type="Italic">tinca</Emphasis> (L.) larvae after a short-term exposure

At the onset of swimbladder inflation, Tinca tinca larvae were exposed for 24 h to cadmium or copper at 0.0 (control concentration), 0.1, 0.2 and 0.3 mg dm⁻³ at 22°C. From then larvae were reared at 25°C for 9 days in un-supplemented water. Both metals resulted in a significantly reduced growth, survival, and retarded swimbladder inflation in a dose-response manner. The highest Cd and Cu concentration delayed the onset of exogenous feeding (live artemia nauplii) for 2 or 1 days, respectively, comparing to the control concentration. Our results demonstrate a highly toxic effect of Cd and Cu in the studied period of larval ontogeny, when fish seem especially sensitive. Although, at low concentrations and long exposure period, Cu is considered more toxic to fish than Cd, our study revealed the reverse effect for first-feeding larvae of both metals at high concentrations and short exposure.     

Sialic Acid-Containing Lipopolysaccharides of Salmonella O48 Strains—Potential Role in Camouflage and Susceptibility to the Bactericidal Effect of Normal Human Serum

Sialic acid (N-acetylneuraminic acid, NeuAc) plays an essential role in protecting gram-negative bacteria against the bactericidal activity of serum and may contribute to the pathogenicity of bacteria by mimicking epitopes that resemble host tissue components (molecular mimicry). The role of sialic acid (NeuAc)-containing lipopolysaccharides (LPS) of Salmonella O48 strains in the complement activation of normal human serum (NHS) was investigated. NeuAc-containing lipooligosaccharides cause a downregulation of complement activation and may serve to camouflage the bacterial surface from the immunological response of the host. Serotype O48 Salmonella strains have the O-antigen structure containing NeuAc while its serovars differ in outer membrane protein composition. In this study, the mechanisms of complement activation responsible for killing Salmonella O48 serum-sensitive rods by NHS were established. Four of such mechanisms involving pathways, which are important in the bactericidal mechanism of complement activation, were distinguished: only the classical/lectin pathways, independent activation of the classical/lectin or alternative pathway, parallel activation of the classical/lectin and alternative pathways, and only the alternative pathway important in the bactericidal action of human serum. To further study the role of NeuAc, its content in bacterial cells was determined by gas-liquid chromatography-mass spectrometry in relation to 3-deoxy-D-manno-2-octulosonic acid (Kdo), an inherent constituent of LPS. The results indicate that neither the presence of sialic acid in LPS nor the length of the O-specific part of LPS containing NeuAc plays a decisive role in determining bacterial resistance to the bactericidal activity of complement and that the presence of sialic acid in the structure of LPS is not sufficient to block the activation of the alternative pathway of complement. We observed that for three strains with a very high NeuAc/Kdo ratio the alternative pathways were decisive in the bactericidal action of human serum. The results indicated that those strains are not capable of inhibiting the alternative pathway very effectively. As the pathogenicity of most Salmonella serotypes remains undefined, research into the interactions between these bacterial cells and host organisms is indispensable.     

Unusual oxidative transformations of a steroidal 16α,17α,22-triol

A number of unexpected reactions were observed during attempts to invert configuration at C16 in 16α,17α,22-triol 3a. The PDC oxidation of 3a produced the D-seco-aldehyde 4a. Analogous compound 4b was obtained by Swern oxidation of the 16α,17α-dihydroxy-22-O-TES-ether 3b in addition to the desired 16-ketone 7. The unprotected triol 3a yielded pentacyclic products 5 and 6 under similar conditions. The Mitsunobu reaction of the triol 3a afforded 16-ketone 8 with inverted configuration of the side chain. During heating of a solution of 3a in THF with NaH at reflux autoxidation to the 16-ketone cyclic hemiketal 5, identical to one of the Swern oxidation products, took place.