The zirconium imido complex Cp2(THF)Zr=NSi(t-Bu)Me2 (1) reacts with allylic ethers, chlorides, and bromides to give exclusively the products of the SN2' reaction; i.e., attack at the allylic position remote from the leaving group with migration of the double bond. The primary amine products can be isolated in excellent yields, after in situ Cbz protection, in the presence of variety of functional groups. Good diastereoselectivity and complete stereoselectivity allowed the formation of enantioenriched allylic amines from enantioenriched allylic ethers. Regiospecific substitution with 1 has also been achieved with allylic fluorides, which are notoriously poor substrates in other substitution reactions. On the basis of rate and kinetic isotope effect studies, we propose a general mechanism for the allylic substitution reactions with 1 which involves dissociation of THF and binding of the substrate, followed by the substitution step. In a DFT study of the substitution reaction, we identified a six-membered closed transition state for the substitution step and other relevant stationary points along the reaction coordinate. This study shows that the substitution reaction can be described as a concerted asynchronous [3,3]-sigmatropic rearrangement. This detailed knowledge of the reaction mechanism provides a rationale for the origins of the observed regio-, diastereo-, and stereoselectivity and of the unusual reactivity profile observed in the reaction.

A detailed mechanism of hydrogen production by reduction of water with decamethyltitanocene triflate [Cp*2 Ti(III) (OTf)] has been derived for the first time, based on a comprehensive in situ spectroscopic study including EPR and ATR-FTIR spectroscopy supported by DFT calculations. It is demonstrated that two H2 O molecules coordinate to [Cp*2 Ti(III) (OTf)] subsequently forming [Cp2 *Ti(III) (H2 O)(OTf)] and [Cp*Ti(III) (H2 O)2 (OTf)]. Triflate stabilizes the water ligands by hydrogen bonding. Liberation of hydrogen proceeds only from the diaqua complex [Cp*Ti(III) (H2 O)2 (OTf)] and involves, most probably, abstraction and recombination of two H atoms from two molecules of [Cp*Ti(III) (H2 O)2 (OTf)] in close vicinity, which is driven by the formation of a strong covalent TiOH bond in the resulting final product [Cp*2 Ti(IV) (OTf)(OH)].

Partial molar heat capacities (CP2 degrees) and volumes (V2 degrees) for some amino acids and peptides were measured in 1 M aqueous calcium chloride solutions at 298.15 degrees K using a Picker flow microcalorimeter and an oscillating-tube digital density meter. Using the data for these amino acids and peptides in water, the corresponding partial molar heat capacities of transfer (CP2,tr degree) and volumes (V2,tr degree) from water to 1 M aqueous calcium chloride were deduced. These thermodynamic parameters are significantly positive, indicating that strong interactions occur between the ions of calcium chloride and the charged centres of these amino acids and peptides. A comparison has been made with a similar transfer of these compounds to sodium chloride solutions. The thermodynamic parameters of the transfer of peptide group (-CONH) are much more positive in calcium chloride than in sodium chloride solutions. The implication of this result for the ability of calcium chloride to act as a stronger destabilizer of protein conformation is discussed.

There is an urgent unmet need for new therapeutics for Alzheimer's disease (AD), the most common cause of dementia in the elderly. Therapeutic approaches targeting amyloid-β (Aβ) and its downstream toxicities have become major strategies in AD drug development. We have taken a rational design approach and synthesized a class of tricyclic pyrone (TP) compounds that show anti-Aβ and other neuroprotective actions. The in vivo efficacy of a lead TP named CP2 to ameliorate AD-like pathologies has been shown in mouse models. Here we report the selection and initial characterization of a new lead TP70, which exhibited an anti-Aβ therapeutic index even higher than CP2. Moreover, TP70 was able to reduce oxidative stress, inhibit acyl-coenzyme A:cholesterol acyltransferase (ACAT), and upregulate the expression of ATP-binding cassette subfamily A, member 1 (ABCA1), actions considered neuroprotective in AD. TP70 further showed excellent pharmacokinetic properties, including brain penetration and oral availability. When administered to 5xFAD mice via intraperitoneal or oral route, TP70 enhanced the overall solubility and decreased the level of cerebral Aβ, including both fibrillary and soluble Aβ species. Interestingly, TP70 enhanced N-methyl-D-aspartate (NMDA) receptor-mediated excitatory post-synaptic potential (EPSP) in the hippocampal CA1 area, increased the magnitude of NMDA-dependent hippocampal long-term potentiation (LTP), a cellular model of learning and memory, and prevented the Aβ oligomer-impaired LTP. Significantly, a single dose of TP70 administered to aged 5xFAD mice was effective in mitigating the impaired LTP induction, recorded at 24 h after administration. Our results support a potential of TP70 in clinical development for AD in view of its synergistic neuroprotective actions, ability to positively modulate NMDA receptor-mediated hippocampal plasticity, and favorable pharmacokinetic properties in rodents.

Common Moroccan breeds D'man, Sardi, and Timahdite have been found to differ regarding litter size. D'man is known for its high prolificacy (2-7 lambs), whereas Timahdite and Sardi are normally prolific (1-2 lambs). Here, we aimed to identify genetic variants in the β promoter and to study the promoter activity amongst these breeds using sequencing for the former and the in vitro luciferase assay for the latter. Sequence analysis revealed 16 genetic variants among these common breeds. Luciferase assay analysis demonstrated a higher promoter activity in D'man compared to the Sardi/Timahdite breeds. A small region of 541 bp was further characterized as possessing a high promoter activity. This region contains 2 palindromic sequences and 7 variants. Based on in silico analysis, only 2 variants at position -559 and -568 were found to be informative. These 2 variants were localized within a region rich in transcription factor binding sites including GATA-1/GATA-2, E4/th1, CP2, and c-Ets. Using site-directed mutagenesis, only the variant at position -559 A/G was found to substantially influence the promoter activity. Taken together, differences in the level of β transcription among highly and minimally prolific Moroccan breeds were demonstrated and a novel single variant was identified that could explain this difference.

Through a series of DFT calculations the energy profile of the Chatt cycle is evaluated. This is the counterpiece of our earlier investigations of the Schrock cycle (Angew. Chem. 2005, 117, 5783; Angew. Chem. Int. Ed. 2005, 44, 5639), applying the same quantumchemical methodology and approximations. As for the Schrock cycle, decamethylchromocene acts as reductant. The protonation reactions are considered to be mediated by HBF4/diethyl ether or lutidinium. For all protonation and reduction steps the corresponding free reaction enthalpy changes are calculated. The derived energy profile and corresponding reaction mechanism bear strong similarities to the Schrock cycle. In particular, the most endergonic reaction is the first protonation of the N2 complex and the most exergonic reaction is the cleavage of the N--N bond. If lutidinium is employed as acid and Cp2*Cr as reductant, the reaction course involves steps that are not thermally allowed. For HBF4/diethyl ether as the acid and Cp2*Cr as reducant, however, a catalytic cycle consisting of thermally allowed reactions is principally feasible. This cycle involves a Mo I-fluoro complex as dinitrogen intermediate. It is shown that regeneration to the Mo 0-bis(dinitrogen) complex is thermally not accessible in this system. Moreover, the Mo I fluoro-dinitrogen complex is labile towards disproportionation. The implications of these results with respect to the realization of a catalytic system on the basis of Mo and W phosphine complexes are discussed.

Peltophorum africanum extracts have been shown to possess many important medicinal benefits, including anti-inflammatory and antiviral activities. However, the mechanism of action is poorly understood. The mechanism of anti-inflammatory action was determined by measuring the synthesis of cytokines in lipopolysaccharide (LPS) stimulated RAW 264.7 macrophage cells in vitro. Compound 1 (CP1), compound 2 (CP2), and fraction F3.3.0 (F3.3.0) significantly reduced the synthesis of interleukin 1β (IL-1β) from RAW 264.7 cells (1.18, 1.32, and 0.92 ng/mL), respectively. Similarly, CP1, CP2, and F3.3.0 inhibited the production of IL-2 and tumor necrosis factor-α (TNF-α) by RAW 264.7 cells (0.41, 0.60, 0.74 and 0.11, 0.27, 0.24 ng/mL, respectively. In addition, CP1 and CP2 had lower cytotoxicity toward RAW 264.7 cells, with CP2 indicating the lowest cytotoxicity (LD50 = 207.88 µg/mL). The mechanism of action was found to be via the inhibition of pro-inflammation cytokines (IL-1 β and TNF-α). This observation may support the use of P africanum to treat pain-related conditions.

This study identified the structural proteins of two badnavirus species, Banana streak MY virus (BSMYV) and Banana streak OL virus (BSOLV), and mapped the distribution of continuous B-cell epitopes. Two different capsid protein (CP) isoforms of about 44 and 40 kDa (CP1 and CP2) and the virion-associated protein (VAP) were consistently associated with purified virions. For both viral species, the N terminus of CP2 was successfully sequenced by Edman degradation but that of CP1 was chemically blocked. De novo peptide sequencing of tryptic digests suggested that CP1 and CP2 derive from the same region of the P3 polyprotein but differ in the length of either the N or the C terminus. A three-dimensional model of the BSMYV-CP was constructed, which showed that the CP is a multi-domain structure, containing homologues of the retroviral capsid and nucleocapsid proteins, as well as a third, intrinsically disordered protein region at the N terminus, henceforth called the NID domain. Using the Pepscan approach, the immunodominant continuous epitopes were mapped to the NID domain for five different species of banana streak virus. Anti-peptide antibodies raised against these epitopes in BSMYV were successfully used for detection of native virions and denatured CPs in serological assays. Immunoelectron microscopy analysis of the virion surface using the anti-peptide antibodies confirmed that the NID domain is exposed on the surface of virions, and that the difference in mass of the two CP isoforms is due to variation in length of the NID domain.

Circular dichroism (c.d.) was measured for four chlorophyll-protein complexes, resolved from sodium dodecyl sulphate extracts of chloroplasts by electrophoresis in polyacrylamide gel containing Deriphat 160 (disodium N-dodecyl beta-imidopropionate), a zwitterionic detergent. The slowest-band (1) complex was found to be identical with the complex CP1 as found on electrophoresis in the presence of anion detergent, but it was in a much higher yield (30% of the chlorophyll a). In band-2 and -3 protein complexes a c.d. pattern described for the complex CP2 could be recognized. Another c.d. component of a split-exciton type with extrema at 680 (-) and 669 (+)nm, together with evidence of disorganized chlorophyll, was found in band-2, -3 and -4 complexes. When a barley (Hordeum vulgare) mutant lacking chlorophyll b was examined, only bands 1 and 4 were obtained, and the c.d. of the band-4 complex was much less affected by disorganized chlorophyll. C.D. spectra resembling that of this band-4 complex could be generated by subtracting the c.d. of complex CP1 from the c.d. of photochemically active mutant chloroplast fragments, or by subtracting the c.d. of complexes CP1 and CP2 from pea (Pisum sativum) chloroplast fragments. The Deriphat appears to have preserved at least to some extent a new type of chlorophyll a-protein complex.

BACKGROUND

The importance of an intact layer of cementum on the root surface in preventing bacterial penetration into radicular dentin has not been sufficiently investigated. The aim of this in vitro study was to determine the effect of the absence of cementum from the root surface and the length of the infection period (2 or 4 weeks) on the maximum depth of bacterial penetration and the percentage of sectors lined with bacteria.

METHODS

Sound, single-rooted extracted teeth with closed apices were randomly assigned to either a control group (cementum present [CP]) or an experimental group (cementum removed [CR]). Each group was further divided randomly into 2 subgroups: 2-week infection (CP2 and CR2) and 4-week infection (CP4 and CR4). Teeth were then artificially infected with Enterococcus faecalis and prepared for histology.

RESULTS

A total of 107 teeth were available for histologic examination, 25 teeth in CP2, 31 teeth in CP4, 27 teeth in CR2, and 24 teeth in CR4. Pairwise comparisons revealed statistically significant differences in the maximum depth of bacterial penetration for the following combinations: CP2-CR2, CP2-CR4, CP4-CR2, and CP4-CR4 (P < .001). Pairwise comparisons also revealed a statistically significant difference in the percentage of sectors lined with bacteria for CP2-CR2, CP2-CP4, and CP2-CR4 (P < .001).

CONCLUSIONS

The results support the hypothesis that the absence of cementum facilitates bacterial penetration into dentinal tubules. Results also suggest that the process of radicular dentin infection is time dependent and highlight the importance of early treatment of infected teeth, especially in situations in which cementum discontinuity is suspected.

In the present study a vancomycin resistant Staphylococcus aureus (S. aureus) (VRSA) (Labeled as CP2) was isolated from the blood of a post-operative cardiac patient is described. It harbors a plasmid which carry vanA gene and exhibited low-level vancomycin resistance (MIC 16μg/mL), was sensitive to teicoplanin. It has been observed that sub-lethal dose of vancomycin induced biofilm formation by CP2 on nylon and silicon indwelling. The results divulge new insights into associations between vancomycin induced biofilms and extra-cellular fatty acids. Gas chromatography coupled with mass spectrometry (GC-MS) revealed that biofilm matrix of CP2 contains a variety of saturated and un-saturated fatty acids, especially, diverse species of octadecanoic (C18:0) and octadecenoic acids (C18:1). A large difference in fatty acids composition was noticed in biofilms, isolated from hydrophobic and hydrophilic surfaces. CP2 produced thicker layer of biofilms on hydrophobic silicon and nylon surfaces which contains variety of saturated, un-saturated and cyclic fatty acids. Contrary to this on hydrophilic glass surfaces it produced thinner layer of biofilm which contains only straight chain saturated fatty acids. These fatty acid components seem to play a crucial role in cell-cell communication and in the establishment of biofilms, consequently, advantageous for pathogens to survive in hospital environment under enormous antibiotics pressure.

Ferrocene, Cp2 Fe, is quantitatively protonated in a mixture of liquid HF/PF5 to yield [Cp2 FeH](PF6 ), which was characterized by 1 H/13 C NMR and 57 Fe Mössbauer spectroscopy as well as single-crystal X-ray diffraction analysis. X-ray diffraction analysis at 100 K revealed a disordered, iron-coordinated hydrido ligand, which was unambiguously located by aspherical atom refinement at 100 K, and by analyzing the non-disordered crystal structure at 30 K, revealing a non-agostic structure.

The one-electron reduction of nitrous oxide (N2 O) was achieved using strong Lewis acids E(C6 F5 )3 (E=B or Al) in combination with metallocenes. In the case of B(C6 F5 )3 , electron transfer to N2 O required a powerful reducing agent such as Cp*2 Co (Cp*=pentamethylcyclopentadienyl). In the presence of Al(C6 F5 )3 , on the other hand, the reactions could be performed with weaker reducing agents such as Cp*2 Fe or Cp2 Fe (Cp=cyclopentadienyl). The Lewis acid-mediated electron transfer from the metallocene to N2 O resulted in cleavage of the N-O bond, generating N2 and the oxyl radical anion [OE(C6 F5 )3 ]⋅- . The latter is highly reactive and engages in C-H activation reactions. It was possible to trap the radical by addition of the Gomberg dimer, which acts as a source of the trityl radical.

The 5'-upstream region of the rat phospholipase C-beta 3 gene (PLC-beta 3) has been cloned and characterized. Sequence analysis of the 5'-upstream region showed that it contains a GC-rich region (-166 to +1: 79%) and multiple binding sites for the transcription factors Sp1, AP-1 and AP-2, but does not contain a canonical TATA box. Primer extension analysis of total RNA isolated from rat glial cell C6Bul revealed that single transcription start point (tsp) is located at an initiator (Inr) element similar to that found in the HIV promoter. Gel mobility shift and competitive mobility shift assays indicated that this Inr element forms a DNA-protein complex with the HIV Inr-binding protein, LBP-1/CP2 or a homologue. In order to localize functional elements of the 5'-upstream region of the rat PLC-beta 3 gene, 5'-deletion fragments were cloned into a chloramphenicol acetyltransferase (CAT) reporter vector. Transient transfection analyses of the 5'-deletion mutants identified a crucial promoter element located at -128 to -14. Supershift mobility assays, site-directed mutagenesis and DNase I footprints indicated that Sp1 binds to three GC boxes within the sequence between -128 and -14 of the PLC-beta 3 promoter. Transient transfection analyses of promoter constructs containing site-specific mutation(s) of these three GC boxes demonstrated that two GC boxes, located proximal to the tsp, are important elements for normal promoter activity.

Dye capture and separation through coordination polymers (CPs) has been a promising research field in recent times due to the toxic and nondegradable nature of organic dyes released into the environment from various industries as well as the reusability of CPs for the said purpose. Here, we report the synthesis and characterization of two mixed ligand CPs {[Zn2(HBTC)2(L)(H2O)2](C2H5OH)3}n (CP1) and {[Zn5(BTC)2(L)3(OH)4(H2O)2](H2O)4(CH3OH)11}n (CP2) (where H3BTC = 1,3,5-benzene tricarboxylic acid and L = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene) by the stoichiometric variation of the precursors. The crystal structure analysis revealed that CP1 is a 2D network composed of a [Zn2(HBTC)2(H2O)2]n motif linked via terminal nitrogen atoms of L and CP2 is a 3D framework in which symmetrically disposed two-dimensional {[Zn5(BTC)2(L)3(OH)4(H2O)2]}n sheets composed of pentanuclear [Zn5(RCO2)6(μ3-OH)2(μ2-OH)2(H2O)2] SBUs are pillared by L ligands. Adsorption and separation of cationic dyes by CP1 and the solid-state fluorescence properties of both CPs have been investigated. Cationic dyes (RhB, MB, and MV) can be effectively adsorbed by CP1 from their aqueous solution (61%, 90%, and 97%, respectively) while the anionic dye methyl orange (MO) remains uncaptured. Dye desorption studies and CP1 as a column chromatographic filler for the separation of cationic dyes in water have also been demonstrated.

Reactions of group 4 metallocene sources with 2-substituted pyridines were investigated to evaluate their coordination type between innocent and reductive dearomatisation as well as to probe the possibility for couplings. A dependence on the cyclopentadienyl ligands (Cp, Cp*), the metals (Ti, Zr), and the substrates (2-phenyl-, 2-acetyl-, and 2-iminopyridine) was observed. While 2-phenylpyridine is barely reactive, 2-acetylpyridine reacts vigorously with the Cp-substituted complexes and selectively with their Cp* analogues. With 2-iminopyridine, in all cases selective reactions were observed. In the isolated [Cp2 Ti], [Cp2 Zr], and [Cp*2 Zr] compounds the substrate coordinates by its pyridyl ring and the unsaturated side-chain. Subsequently, the pyridine was dearomatised, which is most pronounced in the [Cp*2 Zr] compounds. Using [Cp*2 Ti] leads to the unexpected paramagnetic complexes [Cp*2 TiIII (N,O-acpy)] and [Cp*2 TiIII (N,N'-impy)]. This highlights the non-innocent character of the pyridyl substrates.

OBJECTIVE

To improve the specificity and sensitivity of diagnosis and to strengthen postoperative monitoring for patients with ovarian cancer.

METHODS

Sera obtained from patients-ovarian epithelial carcinoma (67 cases), benign ovarian tumor (33 cases) and from donor (38 cases) as control. Serologic examination of 5 tumor markers--SA, LSA, CA125, CP2, and 6B11Ab2 was performed.

RESULTS

The sensitivity and specificity in diagnosis of ovarian cancer were 83.6% and 85.9% respectively for CA125 alone >> 35 kU/L) whereas 86.6% and 94.4% respectively for multi-tumor markers combined in which 3 or more indices showed positive. In addition, serial measurements of multi-tumor markers have been done for 1 year after operation in 24 cases of ovarian epithelial carcinoma. The correlations between the levels of multi-tumor markers either and the results of second look operation or and clinical manifestation of recurrence were analyzed.

CONCLUSIONS

Multi-tumor markers examination could improve the diagnosis of ovarian cancer and early detection of recurrence.

A cyclic-voltammetry-based screening method for Cp2 TiX-catalyzed reactions is introduced. Our mechanism-based approach enables the study of the influence of various additives on the electrochemically generated active catalyst Cp2 TiX, which is in equilibrium with catalytically inactive [Cp2 TiX2 ]- . Thioureas and ureas are most efficient in the generation of Cp2 TiX in THF. Knowing the precise position of the equilibrium between Cp2 TiX and [Cp2 TiX2 ]- allowed us to identify reaction conditions for the bulk electrolysis of Cp2 TiX2 complexes and for Cp2 TiX-catayzed radical arylations without having to carry out the reactions. Our time- and resource-efficient approach is of general interest for the design of catalytic reactions that proceed in single-electron steps.

The reactivity of TiCp2Cl2 (d(0)) towards Zintl clusters was studied in liquid ammonia (Cp = cyclopentadienyl). Reduction of Ti(IV)Cp2Cl2 and ligand exchange led to the formation of [Ti(III)Cp2(NH3)2](+), also obtainable by recrystallization of [CpTi(III)Cl]2. Upon reaction with [K4Sn9], ligand exchange leads to [TiCp2(η(1)-Sn9)(NH3)](3-). A small variation of the stoichiometry led to the formation of [Ti(η(4)-Sn8)Cp](3-), which cocrystallizes with [TiCp2(NH3)2](+) and [TiCp2(η(1)-Sn9)(NH3)](3-). Finally, the large intermetalloid cluster anion [Ti4Sn15Cp5](n-) (n = 4 or 5) was obtained from the reaction of K12Sn17 and TiCp2Cl2 in liquid ammonia. The isolation of three side products, [K([18]crown-6)]Cp, [K([18]crown-6)]Cp(NH3), and [K([2.2]crypt)]Cp, suggests a stepwise elimination of the Cl(-) and Cp(-) ligands from TiCp2Cl2 and thus gives a hint to the mechanism of the product formation in which [Ti(η(4+2)-Sn8)Cp](3-) has a key role.

The present study evaluated the origin and distribution of polycyclic aromatic hydrocarbons (PAHs) and the organic matter (OM) in the surface sediment of the São Paulo River estuary, Todos os Santos Bay (TSB), Brazil. The samples were collected in the rainy (CP1) and the dry (CP2) seasons. We analyzed the 16 PAHs from the United States Environmental Protection Agency (US EPA) priority pollutant list, total organic carbon (TOC), total nitrogen (N), and stable carbon isotope (δ13C). The total concentration of PAHs ranged from 11.45±1.28 to 1825.35±107.96ngg-1, while TOC ranged from 3.8 to 27.7gkg-1. CP1 showed the highest concentrations for all parameters. The δ13C ratio indicated terrigenous OM (-23.81 to -26.63‰). The TOC/N ratio (C/N) indicated transitional OM (12.32 to 24.39), in addition to the continental origin. The diagnostic ratios of PAHs origin revealed only pyrolytic source, although close to areas with a history of petroleum contamination.

We produced a panel of monoclonal antibodies (MAbs) from the fusion of Taura syndrome virus variants from Belize (TSV-BZ) immunized BALB/cJ mouse spleen cells and non-immunoglobulin secreting SP2/0 mouse myeloma cells. One antibody, 2C4, showed strong specificity and sensitivity for TSV in dot-blot immunoassay and immunohistochemistry (IHC) analysis. The MAb reacted against native TSV-BZ, TSV variants from Sinaloa, Mexico (TSV-SI) and TSV variants from Hawaii (TSV-HI) in dot-blot immunoassay. By IHC, the antibody identified the virus in a pattern similar to the digoxigenin-labelled TSV-cDNA probe for the TSV-BZ, TSV-HI and TSV-SI variants, but not for the TSV variants from Venezuela (TSV-VE) and the TSV variants from Thailand (TSV-TH). MAb 2C4 did not react against other shrimp pathogens or with normal shrimp tissue. Western blot analysis showed a strong reaction against CP2, a region of high antigenic variability amongst TSV variants. This antibody has potential diagnostic application in detection and differentiation of certain TSV biotypes.

We report the properties and reactivity of the catalytically active heterologous nitrogenase formed between the Fe protein from Clostridium pasteurianum (Cp2) and the MoFe protein from Klebsiella pneumoniae (Kp1). Under turnover conditions, in the presence of MgATP, a stable 2:1 (Cp2)2Kp1 electron transfer complex is formed, in which the [4Fe-4S]+ centre of Cp2 is protected from chelation by alpha,alpha'-bipyridyl. However, the two Fe protein-binding sites on Kp1 are not equivalent, since a 1:1 Cp2.Kp1 complex was isolated by gel filtration. The non-equivalence of the Fe protein binding sites was also indicated by the inhibition pattern of Klebsiella nitrogenase by Cp2. The EPR spectrum of the isolated 1:1 Cp2.Kp1 complex showed an S=1/2 signal characteristic of dithionite-reduced Cp2 and signals with g values of 4.27, 3.73, 2.01 and 4.32, 3.63, 2.00 characteristic of the high- and low-pH forms of the FeMoco centre of Kp1, respectively. The unoccupied binding site of Kp1 of the isolated 1:1 Cp2Kp1 complex was shown to be catalytically fully functional in combination with Kp2. In contrast to homologous nitrogenases, which require MgATP for detectable rates of electron transfer from the Fe protein, stopped-flow kinetic studies revealed that electron transfer from Cp2 to Kp1 occurred in the absence of MgATP with a rate constant of 0.065 s(-1). Subsequently, a slower transient decrease and restoration of absorption in the electronic spectrum in the 500-700 nm region was observed. These changes corresponded with those in the intensity of the S=3/2 EPR signal of the FeMoco centres of Kp1 and were consistent with the transient reduction of the FeMoco centre of Kp1 to an EPR-silent form, followed by restoration of the signal at longer reaction times. These changes were not associated with catalysis since no evolution of H2 was detectable.

CNR/Pcdhalpha family proteins have been first identified as a receptor family that corporate with Fyn, a family of the Src family of tyrosine kinase, and known as synaptic cadherins. Here we report the complete genomic sequence and organization of the chicken (Gallus gallus) CNR/Pcdhalpha The total length of chicken CNR/Pcdhalpha is 177kb. The chicken CNR/Pcdhalpha cluster encodes 12 variable and 3 constant exons. The genomic organizations of the chicken, rat, mouse, and human CNR/Pcdhalpha are basically orthologous. The constant-region exons (CP1, CP2, and CP3) are highly conserved between chicken and mammals, with percent identities of 90.9%, 90.7%, and 91.8% at the amino-acid level for chicken versus rat, mouse, and human, respectively. In contrast, the percent identities of the variable-region exons between chicken and mammals were lower: 51.8%, 51.3%, and 52.7%, on average, for chicken versus rat, mouse, and human, respectively, at the amino-acid level. Moreover, the chicken variable-region exons (from v1 to v12) are highly conserved paralogously (91.4%: nucleic acid, 92.4%: amino acid) in comparison with those of mammals. The CG content of each variable exon in the chicken (v1 to v12) is 74% on average and the CpG dinucleotide frequency in each variable-region exon is twice that of mammals. Due to the high CG content, chicken variable exons (from v1 to v12) encode 3 to 4 frame-shifted open reading frames, which span 1.5-3.0kb, in both the sense and anti-sense orientations.

Recent datas suggest that the mean power over the final 30 s of a 3-min all-out test is equivalent to Critical Power (CP) using the linear ergometer mode. The purpose of the present study was to identify whether this is also true using an "isokinetic mode". 13 cyclists performed: 1) a ramp test; 2) three 3-min all-out trials to establish End Power (EP) and work done above EP (WEP); and 3) 3 constant work rate trials to determine CP and the work done above CP (W') using the work-time (=CP1/W'1) and 1/time (=CP2/W'2) models. Coefficient of variation in EP was 4.45% between trials 1 and 2, and 4.29% between trials 2 and 3. Limits of Agreement for trials 1-2 and trials 2-3 were -2±38 W. Significant differences were observed between EP and CP1 (+37 W, P<0.001), between WEP and W'1(-6.2 kJ, P=0.001), between EP and CP2 (+31 W, P<0.001) and between WEP and W'2 (-4.2 kJ, P=0.006). Average SEE values for EP-CP1 and EP-CP2 of 7.1% and 6.6% respectively were identified. Data suggest that using an isokinetic mode 3-min all-out test, while yielding a reliable measure of EP, does not provide a valid measure of CP.