Molecular analysis of the recently described lizardfish Saurida lessepsianus (Synodontidae) from the Red Sea and the Mediterranean,with remarks on its phylogeny and genetic bottleneck effect

The opening of the Suez Canal in 1869 led to a massive influx of Red Sea species that invaded the Mediterranean; this was termed ‘Lessepsian migration'. Among these species was a species of lizardfish, identified by some authors as Saurida undosquamis and by others as S. macrolepis. Recently, the Red Sea and the Mediterranean populations were described according to external characteristics as a unique taxon, Saurida lessepsianus. Our molecular study confirms this finding and determines that all previous records of S. undosquamis and S. macrolepis in the Red Sea and the Mediterranean are misidentifications of S. lessepsianus. The Mediterranean population of S. lessepsianus exhibits a lower genetic variability than that of the Red Sea population, suggesting a bottleneck effect.     

Rapid identification of the north-western Pacific billfish species using quantitative real-time polymerase chain reaction techniques

Billfishes are important fishery resources traded and consumed worldwide. As morphological traits are usually removed during processing, molecular methods are applied to identify billfish products. In this study, the approaches of quantitative real-time PCR were developed to identify the six billfish species (Istiompax indica, Istiophorus platypterus, Kajikia audax, Makaira nigricans, Tetrapturus angustirostris and Xiphias gladius) widely distributed in the north-western Pacific Ocean. The developed singleplex systems showed high fidelities to each of the six species via either examining the ΔCt values or melting curve patterns. For samples containing multiple species, individual species are identifiable by a quantitative real-time PCR assay that includes all the singleplex systems. A multiplex system was also developed to identify unknown samples composed of a single species. The methods developed in this study provide a fast and high-throughput manner to identify the north-western Pacific billfish species when morphological traits are unavailable, such as in processed products.     

Development of eggs and larvae of Stolephorus commersonnii and taxonomic key to fish eggs of the Clupeidae and Engraulidae off China

Fish eggs of successive stages of embryonic development, which were identified as belonging to specimens of Commerson's anchovy Stolephorus commersonnii through comparative molecular techniques, were collected from Leqing Bay, Zhejiang, China. Some eggs were reared artificially to obtain samples of successive developmental stages of larvae. The fertilized eggs of S. commersonnii are ellipsoidal and non-adhesive. The surface of the egg membrane is smooth and the perivitelline space is narrow. There is a single oil globule in the irregularly segmented yolk. Newly hatched larvae are transparent and devoid of pigments. Development of the larvae occurs in the following sequence: 8?h after hatching, the anus unfolds; 12?h after hatching, the pectoral fins emerge; 24?h after hatching, the liver and branchial arches emerge, and the alimentary canal differentiates into the oesophagus and intestinal canal; 30?h after hatching, the eyes become pigmented; 36?h after hatching, the upper and lower jaws become distinct; 42?h after hatching, the stellate melanophores emerge; 72?h after hatching, the postlarval developmental stage begins with the emergence of the dorsal fin. Based on the morphology of eggs and larvae of S. commersonnii, a taxonomic key to fish eggs of the Clupeidae and Engraulidae off China is established to provide an efficient and convenient way to identify the egg specimens. The fish eggs of the Clupeidae and Engraulidae off China could be identified to some extent by the buoyancy, shape and diameter of eggs, the number of layers in the egg membrane, the size of the perivitelline space, the number and diameters of oil globules, and the distribution of pigments. Meanwhile, their prelarvae could be identified by the number and diameters of oil globules, the distribution of pigments, the location of the anus and the number of myomeres.     

A click chemistry approach to glycomimetics: Michael addition of 2,3,4,6-tetra-O-acetyl-1-thio-beta-D-glucopyranose to 4-deoxy-1,2-O-isopropylidene-L-glycero-pent-4-enopyranos-3-ulose--a convenient route to novel 4-deoxy-(1-->5)-5-C-thiodisaccharides

The base catalyzed conjugate Michael addition of the 1-thiosugar, 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranose, 1, to a new highly reactive enone 4-deoxy-1,2-O-isopropylidene-L-glycero-pent-4-enopyranos-3-ulose, 2, proceeds steroselectively with formation of adduct 3 in 94% yield. Convenient stereoselective reduction of the C-3 keto function of 3 with L-Selectride followed by in situ acetylation produces thiodisaccharide 4 in good 82% yield. Cleavage of the 1,2-O-isopropylidene protecting group with p-toluenesulfonic acid in methanol, followed by de-O-acetylation, produced an inseparable anomeric mixture of methyl 4-deoxy-5-C-(beta-D-glucopyranosyl)-thio-alpha/beta-L-ribo-pyranoside 5 in 72% overall yield. This approach constitutes a new general two-step click chemistry route to the previously unknown class of 4-deoxy-(1-->5)-5-C-thiodisaccharides as stable and biologically important glycomimetics.     

What does race do?

In writing on ‘John Rex's Main Mistake’, Michael Banton reveals more about Banton than he does about Rex. I use Banton's discussion of the differences between his own and John Rex's ‘mistakes’ to explore why, in my view, race continues to have analytical purchase in a purportedly ‘post-racial’ age     

Organocatalytic aza-Michael/retro-aza-Michael reaction: pronounced chirality amplification in aza-Michael reaction and racemization via retro-aza-Michael reaction

A detailed experimental investigation of an aza-Michael reaction of aniline and chalcone is presented. A series of Cinchona alkaloid-derived organocatalysts with different functional groups were prepared and used in the aza-Michael and retro-aza-Michael reaction. There was an interesting finding that a complete reversal of stereoselectivity when a benzoyl group was introduced to the cinchonine and cinchonidine. The chirality amplification vs. time proceeds in the quinine-derived organocatalyst containing silicon-based bulky group, QN-TBS, -catalyzed aza-Michael reaction under solvent-free conditions. In addition, we have demonstrated for the first time that racemization was occurred in suitable solvents under mild conditions due to retro-aza-Michael reaction of the Michael adduct of aniline with chalcone. These indicate the equilibrium of retro-aza-Michael reaction and aza-Michael reaction produce the happening of chirality amplification in aza-Michael reaction and racemization via retro-aza-Michael reaction under different conditions, which would be beneficial to the development of novel chiral catalysts for the aza-Michael reactions.     

INHIBITORS OF INOSINE MONOPHOSPHATE DEHYDROGENASE: PROBES FOR ANTIVIRAL DRUG DISCOVERY

The role of inosine monophosphate dehydrogenase (IMPDH) at the metabolic branch point of de novo purine nucleotide biosynthesis makes this enzyme an attractive probe for the discovery of antiviral compounds. Introduction of unsaturation at the 2-position of IMP, the natural substrate for IMPDH, produces Michael acceptors at that position, which results in these compounds being inhibitors of IMPDH. Consistent with this mechanism-based molecular design, some of the parent nucleosides exhibited antiviral activity.     

Artificial insemination of subtropical commercial beef cattle following synchronization with cloprostenol (ICI 80996): I. Fertility

Two trials were conducted over a two-year period with 519 cycling Bos taurus x Bos indicus heifers and cows. The objectives of these trials were: 1) To compare fertility of artificial insemination at the cloprostenol-induced estrus and the naturally occurring estrus, 2) To evaluate the fertility of artificial insemination at a predetermined time (Timed AI) following an estrous synchronization regime with cloprostenol (CLP) and 3) To define the optimum interval from a second CLP treatment for Timed AI. In Trial I, 128 animals were assigned to four treatments: 1) Controls, which were inseminated at the natural occurring estrus; 2) timed AI at 72 hr and again at 96 hr post-second CLP; 3) Timed AI at 72 hr post-second CLP and 4) AI at the CLP-induced estrus. Trial II included 391 heifers distributed among six treatments; 1) Timed AI between 70 and 90 hr post-second CLP; 2) Sham AI between 70 and 90 hr post-second CLP, 3) Chute Stress between 70 and 90 hr post-second CLP; 4) AI at the CLP-induced estrus; 5) Control-AI at the naturally occurring estrus and 6) Non-treated and exposed to fertile bulls. The fertility of the animals artificially inseminated at the CLP-induced estrus was similar to that of insemination at the naturally occurring estrus in Trial I and Trial II (30 vs 46%; 37 vs 38%, respectively). The first service pregnancy rates of the animals bred at a predetermined time were similar to those bred at the CLP-induced estrus in Trial I, but lower in Trial II (P < .01).     

Artificial insemination of subtropical commercial beef cattle following synchronization with cloprostenol (ICI 80996): II. Estrous response

Data collected from two controlled breeding field trials involving 561 Bos indicus x Bos taurus cows and heifers were analyzed for estrous and fertility response following a cloprostenol ICI-80, 996 (CLP) synchronization regime. Fertility data were discussed in a companion paper (1). In Trial 1, 128 animals were assigned to four treatments: 1) controls which were inseminated at the naturally occurring estrus; 2) Animals artificially inseminated at approximately 72 hr and 96 hr following a second CLP; 3) Animals artificially inseminated at approximately 72 hr following a second CLP; and 4) Animals artificially inseminated approximately 12 hr after detection of estrus post-second CLP. Trial II included 391 heifers distributed among six treatments: 1) Artificially inseminated between 70 and 90 hr post-second CLP; 2) Sham inseminated between 70 and 90 hr post-second CLP; 3) Processed with no manipulation of the genital tract between 70 and 90 hr post-second CLP; 4) Artificially inseminated approximately 12 hr after the detection of estrus following a second CLP; 5) Artificially inseminated at the naturally occurring estrus and 6) Non-treated heifers exposed to fertile bulls. Cloprostenol ICI-80996 was effective (P < .01) in synchronizing estrus in comparisons of treated vs non-treated controls in Trials I and II (82 vs 29%; 57 vs 19%, respectively). However, a significant reduction in the expression of estrus was observed following Timed AI when compared to heifers bred 12 hr after detection of CLP-induced estrus in Trial II (37 vs 54%, P < .05). The authors conclude that a single timed insemination of Brahman crossbred heifers suppresses the behavioral expression of estrus. Other evidence (1) indicates that the fertility during this period is similarly reduced.     

The isolated Photosystem II reaction center: first attempts to directly measure the kinetics of primary charge separation

Direct measurements of the intrinsic rate of primary charge separation in the isolated Photosystem II (PS II) reaction center complex had to await the availability of suitable, stabilized reaction center materials as well as sophisticated femtosecond transient absorption spectroscopic techniques. The events that led to the first direct measurements of the primary charge separation act in PS II and discussions of the results thereafter are chronicled in this brief historical review. This revised version was published online in August 2006 with corrections to the Cover Date.     

Novel asymmetric oxy-michael addition reaction of the chiral ketones to the achiral gamma--or delta-hydroxy-alpha,beta-unsaturated carbonyl compounds

A novel asymmetric oxy-Michael addition reaction was developed. In the presence of a catalytic amount of base, chiral ketones 1 and 2, derived from D-glucose and D-fructose, respectively, reacted with omega-hydroxy enones or enoates 3a-e, 17 and 21 to form the hemiacetal-derived alkoxide which underwent stereoselective intramolecular Michael addition to give cyclic acetals. Although the stereoselectivities in the formation of the five-membered acetal rings were modest, six-membered ring formation proceeded with high stereoselectivity and the utility of the reaction was demonstrated by a simple syntheses of natural products.     

A fluorescent probe for biothiols based on the conjugate addition of thiols to α,β‐unsaturated ester

A sensitive fluorogenic probe 1 for biothiols was developed based on the Michael addition reaction. The probe 1 was readily synthesized via the reaction of 2‐(4′‐hydroxyphenyl) benzimidazole (HPBI) with acryloyl chloride and shows weak fluorescence emission. Upon mixing with biothiols, the fluorescence of 1 is significantly enhanced due to the conjugate addition of thiols to the α,β‐unsaturated carbonyl moiety, thus eliminating the photoinduced electron transfer (PET) quenching of the fluorophore by the intramolecular carbon–carbon double bond. Cysteine (Cys) was selected as the representative thiol in the spectral experiment. A good linear relationship was obtained from 1.0 to 30.0 µmol L^?1 for Cys and the detection limit was 0.17 µmol L^?1. Furthermore, probe 1 was highly selective for biothiols without the interference of some biologically relevant analytes and has been applied to detecting biothiols in human urine samples. Copyright © 2010 John Wiley & Sons, Ltd.     

A coumarin‐based fluorescent turn‐on probe for detection of biothiols in vitro

A novel fluorescent probe (CA‐N) was designed and synthesized for detection of biothiols. CA‐N displayed a strong fluorescence in the presence of biothiols with high sensitivity, and the mechanism for detection biothiols was based on the Michael addition reaction of a thiol group to α,β‐unsaturated ketones. CA‐N showed low detection limit for cysteine (Cys), homocysteine (Hcy), and glutathione (GSH), which were calculated as 3.16, 0.19 and 5.15 μM, respectively. At the same time, CA‐N exhibited high selectivity toward biothiols compared with other biological amino acids. In vitro cell experiments proved that CA‐N had no cytotoxicity, high cell permeability and could be employed in living cell imaging for biothiols. Copyright © 2015 John Wiley & Sons, Ltd.     

Comparative Epistemology: Contours of a Research Program

This article addresses the question whether and how literary documents can be used to further our understanding of a number of key issues on the agenda of the philosophy of biology such as “complexity” and “reductionism”. Kant already granted a certain respectability to aesthetical experiences of nature in his third Critique. Subsequently, the philosophical movement known as phenomenology often used literary sources and literary techniques to criticize and question mainstream laboratory science. The article discusses a number of literary documents, from Moby-Dick to Jurassic Park, that explicitly stage a confrontation between scientific and non-scientific ways of experiencing and understanding the natural world. Special attention is given to the work of Michael Crichton. Its relevance for the philosophy of biology is pointed out.     

Characterization and quantification of endogenous fatty acid nitroalkene metabolites in human urine

The oxidation and nitration of unsaturated fatty acids transforms cell membrane and lipoprotein constituents into mediators that regulate signal transduction. The formation of 9-NO₂-octadeca-9,11-dienoic acid and 12-NO₂-octadeca-9,11-dienoic acid stems from peroxynitrite- and myeloperoxidase-derived nitrogen dioxide reactions as well as secondary to nitrite disproportionation under the acidic conditions of digestion. Broad anti-inflammatory and tissue-protective responses are mediated by nitro-fatty acids. It is now shown that electrophilic fatty acid nitroalkenes are present in the urine of healthy human volunteers (9.9 ± 4.0 pmol/mg creatinine); along with electrophilic 16- and 14-carbon nitroalkenyl β-oxidation metabolites. High resolution mass determinations and coelution with isotopically-labeled metabolites support renal excretion of cysteine-nitroalkene conjugates. These products of Michael addition are in equilibrium with the free nitroalkene pool in urine and are displaced by thiol reaction with mercury chloride. This reaction increases the level of free nitroalkene fraction >10-fold and displays a K_D of 7.5 × 10⁻⁶ M. In aggregate, the data indicates that formation of Michael adducts by electrophilic fatty acids is favored under biological conditions and that reversal of these addition reactions is critical for detecting both parent nitroalkenes and their metabolites. The measurement of this class of mediators can constitute a sensitive noninvasive index of metabolic and inflammatory status.     

Synthesis of iminoalditol and N-alkyl iminoalditol derivatives of ribopyranosides

Iminoalditol analogs of ribopyranosides were prepared by reduction of a vinylogous urethane intermediate formed from methyl 2-C-(5-O-methanesulfonyl-β-d-ribofuranosyl)acetate (1) by treatment with sodium azide in DMF at reflux. The N-alkylated analogs were synthesized either by N-alkylation of the corresponding parent iminoaldithol or, more efficiently, from the product of the reaction of 1 with various alkylamines. The latter process involves an S_N2 substitution at C-5 by the amine followed by an intramolecular hetero-Michael reaction under basic conditions. The ‘aglycon’ of the iminoalditol was also modified through amidation and esterification.     

Catalytic promiscuity of Escherichia coli BioH esterase: Application in the synthesis of 3,4-dihydropyran derivatives

Enzymatic catalytic promiscuity has received increasing attention in the past decade. In this research, ten enzymes were investigated for the promiscuous activity in catalysis of the Michael addition-cyclization cascade reaction of p-nitrobenzalacetone with 1,3-cyclohexanedione to prepare 2-hydroxy-2-methyl-4-(4-nitrophenyl)-3,4,7,8-tetrahydro-2H-chromen-5(6H)-one in anhydrous media, and control experiments were conducted to exclude false positive results. The highest yield (46.1%) was observed with Escherichia coli BioH esterase and the optimal reaction condition was: 1 mmol α,β-unsaturated ketone, 1 mmol 1,3-dicarbonyl compound, 20 mg E. coli BioH esterase, 20 ml N,N-dimethylformamide at 37 °C for 120 h. To preliminarily investigate the mechanism, site-directed mutagenesis was performed on the hydrolysis catalytic triad of BioH, and the results indicated “alternate-site enzyme promiscuity”. When a series of substituted benzalacetones and 1,3-cyclic diketones were used as the reactants, yields of up to 76.3% were achieved. These results imply the potential industrial application of E. coli BioH in the preparation of dihydropyran derivatives.     

Novel Chiral Bifunctional L‐Thiazoline‐Thiourea Derivatives: Design and Application in Enantioselective Michael Reactions

Several novel chiral bifunctional L‐thiazoline‐thiourea derivatives were easily synthesized from commercially available L‐cysteine in high yield. These catalysts were subsequently applied to the enantioselective Michael addition of acetylacetone to β‐nitrostyrenes. The products with S configuration were obtained in 98% enantiomeric excess (ee) when the L‐thiazoline‐thiourea derivatives were used. A plausible transition state model is proposed to explain the observed enantioselectivities. Chirality 27:979–988, 2015. © 2015 Wiley Periodicals, Inc.