Bomb <Superscript>14</Superscript>C enrichment indicates decadal C pool in deep soil?

Studies of changes in soil organic carbon (SOC) stocks normally limit their focus to the upper 20–30 cm of soil, yet 0–20 cm SOC stocks are only ∼40% of 0–1 m SOC. Accounting for only the upper 20–30 cm of SOC has been justifiable assuming that deeper SOC is unreactive since it displays ¹⁴C-derived mean residence times of hundreds or thousands of years. The dramatic increase in the ¹⁴C content of the atmosphere resulting from thermonuclear testing circa 1963 allows the unreactivity of deep SOC to be tested by examining whether deep soils show evidence of ‘bomb-¹⁴C’ incorporation. At depths of 40–100 cm, a well-studied New Zealand soil under stable pastoral management displays progressive enrichment of over 200‰ across samplings in 1959, 1974 and 2002, indicating substantial incorporation of bomb ¹⁴C. This pattern of deep ¹⁴C enrichment—previously observed in 2 well-drained California grassland soils—leads to the hypothesis that roots and/or dissolved organic C transport contribute to a decadally-reactive SOC pool comprising ∼10–40% of SOC below 50 cm. Deep reactive SOC may be important in the global C cycle because it can react to land-use or vegetation change and may respond to different processes than the reactive SOC in the upper 20–30 cm of soil.     

Sensitive <Superscript>13</Superscript>C–<Superscript>13</Superscript>C correlation spectra of amyloid fibrils at very high spinning frequencies and magnetic fields

Sensitive 2D solid-state ¹³C–¹³C correlation spectra of amyloid β fibrils have been recorded at very fast spinning frequencies and very high magnetic fields. It is demonstrated that PARIS-xy recoupling using moderate rf amplitudes can provide structural information by promoting efficient magnetization transfer even under such challenging experimental conditions. Furthermore, it has been shown both experimentally and by numerical simulations that the method is not very sensitive to dipolar truncation effects and can reveal direct transfer across distances of about 3.5–4Å.     

Promiscuous esterase activities of the C–C hydrolases from <Emphasis Type="Italic">Dyella ginsengisoli</Emphasis>

A C–C hydrolase gene (bphD _LA-4 ) from strain Dyella ginsengisoli LA-4 was cloned and expressed in Escherichia coli BL21 (DE3). BphD_LA-4 together with another hydrolase MfphA_LA-4, which derived from the same strain, possessed esterase activities. p-Nitrophenyl butyrate was the best substrate for both enzymes. BphD_LA-4 had high catalytic efficiency to p-nitrophenyl benzoate, whereas MfphA_LA-4 had no activity. Homology modeling and docking studies demonstrated that the proper hydrogen bond interaction was important for the reactivity of specific substrate.     

“瑞草”灵芝之现代研究

"灵芝"一词最早出现于东汉,人们"以为瑞草,服之神仙",称之为"灵芝"。现指隶属于真菌界Fungi、担子菌门Basidiomycota、伞菌纲Agaricomycetes、多孔菌目Polyporales、灵芝科Ganodermataceae的一类传统药用真菌的统称,具有免疫调节、抗肿瘤、抗氧化、抑菌、保肝护肝、止咳平喘等多种功效(林志彬2015;Gilletal.2016;Ahmad2018;Wuetal.     

Influences of −482C&gt;T and 3238G&gt;C polymorphisms of the <Emphasis Type="Italic">Apolipoprotein C3</Emphasis> gene on prevalence of metabolic syndrome

Apolipoprotein C3 (ApoC3) plays a regulatory role in triglyceride (TG) metabolism. The higher level of TG can be a cause in pathogenesis of the vascular diseases or metabolic syndrome (MetS). In this study, we examined the associations of ApoC3 polymorphisms (?482C>T rs2854117 and 3238G>C rs5128) with Korean MetS patients. A total of 835 subjects were investigated, including 320 patients with MetS and 515 healthy subjects. The genotype analysis of the ApoC3 polymorphisms was performed by polymerase chain reaction-restriction fragment length polymorphism methods. Of the two polymorphisms studied, we observed a significant difference in the ?482C>T polymorphism between the MetS and control groups. The TT genotype of the ?482C>T polymorphism was associated with increased risk for MetS, compared with the controls (OR 1.627, 95 % CI 1.075–2.463, P = 0.021). The association was female-specific. No associations were found for the risk of MetS in the 3238G>C polymorphism. Haplotypes composed of two polymorphisms, however, were associated with MetS susceptibility in only male group. The 3238G>C polymorphism was significantly associated with TG levels (P = 0.013). Our data suggest that the ApoC3 ?482C>T polymorphism is associated with increased MetS susceptibility in the Korean population.     

Characterization of the Differential Roles of the Twin C1a and C1b Domains of Protein Kinase C��

Classic and novel protein kinase C (PKC) isozymes contain two zinc finger motifs, designated “C1a” and “C1b” domains, which constitute the recognition modules for the second messenger diacylglycerol (DAG) or the phorbol esters. However, the individual contributions of these tandem C1 domains to PKC function and, reciprocally, the influence of protein context on their function remain uncertain. In the present study, we prepared PKCδ constructs in which the individual C1a and C1b domains were deleted, swapped, or substituted for one another to explore these issues. As isolated fragments, both the δC1a and δC1b domains potently bound phorbol esters, but the binding of [³H]phorbol 12,13-dibutyrate ([³H]PDBu) by the δC1a domain depended much more on the presence of phosphatidylserine than did that of the δC1b domain. In intact PKCδ, the δC1b domain played the dominant role in [³H]PDBu binding, membrane translocation, and down-regulation. A contribution from the δC1a domain was nonetheless evident, as shown by retention of [³H]PDBu binding at reduced affinity, by increased [³H]PDBu affinity upon expression of a second δC1a domain substituting for the δC1b domain, and by loss of persistent plasma membrane translocation for PKCδ expressing only the δC1b domain, but its contribution was less than predicted from the activity of the isolated domain. Switching the position of the δC1b domain to the normal position of the δC1a domain (or vice versa) had no apparent effect on the response to phorbol esters, suggesting that the specific position of the C1 domain within PKCδ was not the primary determinant of its activity.One of the essential steps for protein kinase C (PKC)² activation is its translocation from the cytosol to the membranes. For conventional (α, βI, βII, and γ) and novel (δ, ε, η, and θ) PKCs, this translocation is driven by interaction with the lipophilic second messenger sn-1,2-diacylglycerol (DAG), generated from phosphatidylinositol 4,5-bisphosphate upon the activation of receptor-coupled phospholipase C or indirectly from phosphatidylcholine via phospholipase D (1). A pair of zinc finger structures in the regulatory domain of the PKCs, the “C1” domains, are responsible for the recognition of the DAG signal. The DAG-C1 domain-membrane interaction is coupled to a conformational change in PKC, both causing the release of the pseudosubstrate domain from the catalytic site to activate the enzyme and triggering the translocation to the membrane (2). By regulating access to substrates, PKC translocation complements the intrinsic enzymatic specificity of PKC to determine its substrate profile.The C1 domain is a highly conserved cysteine-rich motif (∼50 amino acids), which was first identified in PKC as the interaction site for DAG or phorbol esters (3). It possesses a globular structure with a hydrophilic binding cleft at one end surrounded by hydrophobic residues. Binding of DAG or phorbol esters to the C1 domain caps the hydrophilic cleft and forms a continuous hydrophobic surface favoring the interaction or penetration of the C1 domain into the membrane (4). In addition to the novel and classic PKCs, six other families of proteins have also been identified, some of whose members possess DAG/phorbol ester-responsive C1 domains. These are the protein kinase D (5), the chimaerin (6), the munc-13 (7), the RasGRP (guanyl nucleotide exchange factors for Ras and Rap1) (8), the DAG kinase (9), and the recently characterized MRCK (myotonic dystrophy kinase-related Cdc42-binding kinase) families (10). Of these C1 domain-containing proteins, the PKCs have been studied most extensively and are important therapeutic targets (11). Among the drug candidates in clinical trials that target PKC, a number such as bryostatin 1 and PEP005 are directed at the C1 domains of PKC rather than at its catalytic site.Both the classic and novel PKCs contain in their N-terminal regulatory region tandem C1 domains, C1a and C1b, which bind DAG/phorbol ester (12). Multiple studies have sought to define the respective roles of these two C1 domains in PKC regulation, but the issue remains unclear. Initial in vitro binding measurements with conventional PKCs suggested that 1 mol of phorbol ester bound per mole of PKC (13-15). On the other hand, Stubbs et al., using a fluorescent phorbol ester analog, reported that PKCα bound two ligands per PKC (16). Further, site-directed mutagenesis of the C1a and C1b domains of intact PKCα indicated that the C1a and C1b domains played equivalent roles for membrane translocation in response to phorbol 12-myristate 13-acetate (PMA) and (-)octylindolactam V (17). Likewise, deletion studies indicated that the C1a and C1b domains of PKCγ bound PDBu equally with high potency (3, 18). Using a functional assay with PKCα expression in yeast, Shieh et al. (19) deleted individual C1 domains and reported that C1a and C1b were both functional and equivalent upon stimulation by PMA, with either deletion causing a similar reduction in potency of response, whereas for mezerein the response depended essentially on the C1a domain, with much weaker response if only the C1b domain was present. Using isolated C1 domains, Irie et al. (20) suggested that the C1a domain of PKCα but not those of PKCβ or PKCγ bound [³H]PDBu preferentially; different ligands showed a generally similar pattern but with different extents of selectivity. Using synthesized dimeric bisphorbols, Newton''s group reported (21) that, although both C1 domains of PKCβII are oriented for potential membrane interaction, only one C1 domain bound ligand in a physiological context.In the case of novel PKCs, many studies have been performed on PKCδ to study the equivalency of the twin C1 domains. The P11G point mutation of the C1a domain, which caused a 300-fold loss of binding potency in the isolated domain (22), had little effect on the phorbol ester-dependent translocation of PKCδ in NIH3T3 cells, whereas the same mutation of the C1b caused a 20-fold shift in phorbol ester potency for inducing translocation, suggesting a major role of the C1b domain for phorbol ester binding (23). A secondary role for the C1a domain was suggested, however, because mutation in the C1a domain as well as the C1b domain caused a further 7-fold shift in potency. Using the same mutations in the C1a and C1b domains, Bögi et al. (24) found that the binding selectivity for the C1a and C1b domains of PKCδ appeared to be ligand-dependent. Whereas PMA and the indole alkaloids indolactam and octylindolactam were selectively dependent on the C1b domain, selectivity was not observed for mezerein, the 12-deoxyphorbol 13-monoesters prostratin and 12-deoxyphorbol 13-phenylacetate, and the macrocyclic lactone bryostatin 1 (24). In in vitro studies using isolated C1a and C1b domains of PKCδ, Cho''s group (25) described that the two C1 domains had opposite affinities for DAG and phorbol ester; i.e. the C1a domain showed high affinity for DAG and the C1b domain showed high affinity for phorbol ester. No such difference in selectivity was observed by Irie et al. (20).PKC has emerged as a promising therapeutic target both for cancer and for other conditions, such as diabetic retinopathy or macular degeneration (26-30). Kinase inhibitors represent one promising approach for targeting PKC, and enzastaurin, an inhibitor with moderate selectivity for PKCβ relative to other PKC isoforms (but still with activity on some other non-PKC kinases) is currently in multiple clinical trials. An alternative strategy for drug development has been to target the regulatory C1 domains of PKC. Strong proof of principle for this approach is provided by multiple natural products, e.g. bryostatin 1 and PEP005, which are likewise in clinical trials and which are directed at the C1 domains. A potential advantage of this approach is the lesser number of homologous targets, <30 DAG-sensitive C1 domains compared with over 500 kinases, as well as further opportunities for specificity provided by the diversity of lipid environments, which form a half-site for ligand binding to the C1 domain. Because different PKC isoforms may induce antagonistic activities, inhibition of one isoform may be functionally equivalent to activation of an antagonistic isoform (31).Along with the benzolactams (20, 32), the DAG lactones have provided a powerful synthetic platform for manipulating ligand: C1 domain interactions (31). For example, the DAG lactone derivative 130C037 displayed marked selectivity among the recombinant C1a and C1b domains of PKCα and PKCδ as well as substantial selectivity for RasGRP relative to PKCα (33). Likewise, we have shown that a modified DAG lactone (dioxolanones) can afford an additional point of contact in ligand binding to the C1b domain of PKCδ (34). Such studies provide clear examples that ligand-C1 domain interactions can be manipulated to yield novel patterns of recognition. Further selectivity might be gained with bivalent compounds, exploiting the spacing and individual characteristics of the C1a and C1b domains (35). A better understanding of the differential roles of the two C1 domains in PKC regulation is critical for the rational development of such compounds. In this study, by molecularly manipulating the C1a or C1b domains in intact PKCδ, we find that both the C1a and C1b domains play important roles in PKCδ regulation. The C1b domain is predominant for ligand binding and for membrane translocation of the whole PKCδ molecule. The C1a domain of intact PKCδ plays only a secondary role in ligand binding but stabilizes the PKCδ molecule at the plasma membrane for downstream signaling. In addition, we show that the effect of the individual C1 domains of PKCδ does not critically depend on their position within the regulatory domain.     

Molecular evolution of C4 phospho<Emphasis Type="Italic">enol</Emphasis>pyruvate carboxylase in the genus<Emphasis Type="Italic"> Flaveria</Emphasis>—a gradual increase from C3 to C4 characteristics

In order to elucidate the discrete steps in phospho enolpyruvate carboxylase (PEPC) evolution concerning K(m)-PEP and malate tolerance a comparison was made between C3, C3-C4 and C4 species of the dicot genus Flaveria. The PEPCs of this genus are encoded by a gene family comprising three classes: ppcA, ppcB and ppcC [J. Hermans and P. Westhoff (1990) Mol Gen Genet 224:459-468, (1992) Mol Gen Genet 234:275-284]. The ppcA of F trinervia (C4) codes for the C4 PEPC isoform but other plants of the genus contain ppcA orthologues too. The C3 plant F. pringlei showed the lowest levels of ppcA PEPC mRNA followed by F. pubescens (C3-C4) while the C4-like plant F. brownii displayed RNA amounts close to the C4 species F. trinervia. In contrast to the similar expression profiles of F. brownii (C4-like) and F. trinervia (C4) the PEPC amino acid sequence of F. brownii was more similar to the C3 and C3-C4 ppcA PEPCs than to the C4 PEPC. Similarly, the C3, C3-C4 and C4-like ppcA PEPCs showed almost identical PEP saturation kinetics when activated by glucose-6-phosphate ( K(m)-PEP: 17-20 microM) while the K(m)-PEP for the C4 PEPC was determined to be 53 microM. However, without activation the ppcA PEPCs of F. pubescens and F. brownii displayed C3-C4 intermediate values. A similar picture was obtained when the malate sensitivities were compared. In the non-activated state the F. trinervia (C4) enzyme was 10 times more tolerant to malate than the F. pringlei counterpart. The ppcA enzymes of F. pubescens (C3-C4) and F. brownii (C4-like) displayed intermediate values. In contrast, the inclusion of 5 mM glucose-6-phosphate in the reaction mixture changed the order totally. Interestingly, the activation rendered the C4 enzyme about 50% less tolerant to malate than the C3 PEPC. The activation had a positive effect on malate tolerance of the F. pubescens (C3-C4) PEPC while the ppcA PEPC of F. brownii (C4-like) was almost unaffected.     

Fractional <Superscript>13</Superscript>C enrichment of isolated carbons using [1-<Superscript>13</Superscript>C]- or [2-<Superscript>13</Superscript>C]-glucose facilitates the accurate measurement of dynamics at backbone C<Superscript>α</Superscript> and side-chain methyl positions in proteins

A simple labeling approach is presented based on protein expression in [1-¹³C]- or [2-¹³C]-glucose containing media that produces molecules enriched at methyl carbon positions or backbone C^α sites, respectively. All of the methyl groups, with the exception of Thr and Ile(δ1) are produced with isolated ¹³C spins (i.e., no ¹³C–¹³C one bond couplings), facilitating studies of dynamics through the use of spin-spin relaxation experiments without artifacts introduced by evolution due to large homonuclear scalar couplings. Carbon-α sites are labeled without concomitant labeling at C^β positions for 17 of the common 20 amino acids and there are no cases for which ¹³C^α−¹³CO spin pairs are observed. A large number of probes are thus available for the study of protein dynamics with the results obtained complimenting those from more traditional backbone ¹⁵N studies. The utility of the labeling is established by recording ¹³C R _1ρ and CPMG-based experiments on a number of different protein systems.     

AFLP and SSR polymorphism in a <Emphasis Type="Italic">Coffea</Emphasis> interspecific backcross progeny [(<Emphasis Type="Italic">C. heterocalyx</Emphasis> × <Emphasis Type="Italic">C. canephora</Emphasis>) × <Emphasis Type="Italic">C. canephora</Emphasis>]

An interspecific cross (BC 1) involving a species with one of the largest genomes in the Coffea genus [Coffea heterocalyx (HET), qDNA = 1.74 pg] and a species with a medium-sized genome [Coffea canephora (CAN), qDNA = 1.43 pg] was studied using two types of molecular markers, AFLP and SSR. One hundred and eighty eight AFLP bands and 34 SSR primer pairs were suitable for mapping. The total map length was 1,360 cM with 190 loci distributed in 15 linkage groups. The results were compared to those obtained previously on an interspecific BC 1 progeny involving a species with a medium-sized genome (Coffea liberica var dewevrei, DEW) and a species with one of the smallest genomes (Coffea pseudozanguebariae, PSE). They are discussed relative to three main points: (1) the relevance of the different marker types, (2) the genomic distribution of AFLP and SSR markers, and (3) the relation between AFLP polymorphism and genome size.Communicated by H.F. Linskens     

CACA-TOCSY with alternate <Superscript>13</Superscript>C–<Superscript>12</Superscript>C labeling: a <Superscript>13</Superscript>C<Superscript>α</Superscript> direct detection experiment for mainchain resonance assignment,dihedral angle information,and amino acid type identification

We present a ¹³C direct detection CACA-TOCSY experiment for samples with alternate ¹³C–¹²C labeling. It provides inter-residue correlations between ¹³C^α resonances of residue i and adjacent C^αs at positions i − 1 and i + 1. Furthermore, longer mixing times yield correlations to C^α nuclei separated by more than one residue. The experiment also provides C^α-to-sidechain correlations, some amino acid type identifications and estimates for ψ dihedral angles. The power of the experiment derives from the alternate ¹³C–¹²C labeling with [1,3-¹³C] glycerol or [2-¹³C] glycerol, which allows utilizing the small scalar ³J_CC couplings that are masked by strong ¹J_CC couplings in uniformly ¹³C labeled samples.     

Coral skeletal carbon isotopes (δ<Superscript>13</Superscript>C and Δ<Superscript>14</Superscript>C) record the delivery of terrestrial carbon to the coastal waters of Puerto Rico

Tropical small mountainous rivers deliver a poorly quantified, but potentially significant, amount of carbon to the world’s oceans. However, few historical records of land–ocean carbon transfer exist for any region on Earth. Corals have the potential to provide such records, because they draw on dissolved inorganic carbon (DIC) for calcification. In temperate systems, the stable- (δ¹³C) and radiocarbon (Δ¹⁴C) isotopes of coastal DIC are influenced by the δ¹³C and Δ¹⁴C of the DIC transported from adjacent rivers. A similar pattern should exist in tropical coastal DIC and hence coral skeletons. Here, δ¹³C and Δ¹⁴C measurements were made in a 56-year-old Montastraea faveolata coral growing ~1 km from the mouth of the Rio Fajardo in eastern Puerto Rico. Additionally, the δ¹³C and Δ¹⁴C values of the DIC of the Rio Fajardo and its adjacent coastal waters were measured during two wet and dry seasons. Three major findings were observed: (1) synchronous depletions of both δ¹³C and Δ¹⁴C in the coral skeleton are annually coherent with the timing of peak river discharge, (2) riverine DIC was always more depleted in δ¹³C and Δ¹⁴C than seawater DIC, and (3) the correlation of δ¹³C and Δ¹⁴C was the same in both coral skeleton and the DIC of the river and coastal waters. These results indicate that coral skeletal δ¹³C and Δ¹⁴C are recording the delivery of riverine DIC to the coastal ocean. Thus, coral records could be used to develop proxies of historical land–ocean carbon flux for many tropical regions. Such information could be invaluable for understanding the role of tropical land–ocean carbon flux in the context of land-use change and global climate change.     

Accurate measurement of <Superscript>15</Superscript>N–<Superscript>13</Superscript>C residual dipolar couplings in nucleic acids

New 3D HCN quantitative J (QJ) pulse schemes are presented for the precise and accurate measurement of one-bond ¹⁵N_1/9–¹³C₁, ¹⁵N_1/9–¹³C_6/8, and ¹⁵N_1/9–¹³C_2/4 residual dipolar couplings (RDCs) in weakly aligned nucleic acids. The methods employ ¹H–¹³C multiple quantum (MQ) coherence or TROSY-type pulse sequences for optimal resolution and sensitivity. RDCs are obtained from the intensity ratio of H₁–C₁–N_1/9 (MQ-HCN-QJ) or H_6/8–C_6/8–N_1/9 (TROSY-HCN-QJ) correlations in two interleaved 3D NMR spectra, with dephasing intervals of zero (reference spectrum) and 1/(2J_NC) (attenuated spectrum). The different types of ¹⁵N–¹³C couplings can be obtained by using either the 3D MQ-HCN-QJ or TROSY-HCN-QJ pulse scheme, with the appropriate setting of the duration of the constant-time ¹⁵N evolution period and the offset of two frequency-selective ¹³C pulses. The methods are demonstrated for a uniformly ¹³C, ¹⁵N-enriched 24-nucleotide stem-loop RNA sequence, helix-35, aligned in the magnetic field using phage Pf1. For measurements of RDCs systematic errors are found to be negligible, and experiments performed on a 1.5 mM helix-35 sample result in an estimated precision of ca. 0.07 Hz for ¹D_NC, indicating the utility of the measured RDCs in structure validation and refinement. Indeed, for a complete set of ¹⁵N_1/9–¹³C₁, ¹⁵N_1/9–¹³C_6/8, and ¹⁵N_1/9–¹³C_2/4 dipolar couplings obtained for the stem nucleotides, the measured RDCs are in excellent agreement with those predicted for an NMR structure of helix-35, refined using independently measured observables, including ¹³C–¹H, ¹³C–¹³C and ¹H–¹H dipolar couplings.Supplementary material to this paper is available in electronic form at http://dx.doi.org/10.1007/s10858-005-0646-2.     

Major groove width variations in RNA structures determined by NMR and impact of <Superscript>13</Superscript>C residual chemical shift anisotropy and <Superscript>1</Superscript>H–<Superscript>13</Superscript>C residual dipolar coupling on refinement

Ribonucleic acid structure determination by NMR spectroscopy relies primarily on local structural restraints provided by ¹H– ¹H NOEs and J-couplings. When employed loosely, these restraints are broadly compatible with A- and B-like helical geometries and give rise to calculated structures that are highly sensitive to the force fields employed during refinement. A survey of recently reported NMR structures reveals significant variations in helical parameters, particularly the major groove width. Although helical parameters observed in high-resolution X-ray crystal structures of isolated A-form RNA helices are sensitive to crystal packing effects, variations among the published X-ray structures are significantly smaller than those observed in NMR structures. Here we show that restraints derived from aromatic ¹H– ¹³C residual dipolar couplings (RDCs) and residual chemical shift anisotropies (RCSAs) can overcome NMR restraint and force field deficiencies and afford structures with helical properties similar to those observed in high-resolution X-ray structures.     

ΦC31整合酶与转基因动物研制

链霉菌噬菌体 C31整合酶是一种位点性特异重组酶。它以单向整合方式进行重组,无须其他辅助因子,且整合效率高、表达稳定,所以近年来越来越多地被用来介导外源基因与宿主基因组的特异性整合,并被应用于哺乳动物的转基因整合技术中,它为攻克转基因动物研制过程中的随机整合、整合效率低、表达水平不高等技术瓶颈提供了新思路。本文将对链霉菌噬菌体 C31整合酶的作用机制和特点优势作简要的阐述,并对其广阔的应用前景作一展望。     

Comprehensive determination of <Superscript>3</Superscript>J<Subscript>HNHα</Subscript> for unfolded proteins using <Superscript>13</Superscript>C′-resolved spin-echo difference spectroscopy

An experiment is presented to determine ³J_HNHα coupling constants, with significant advantages for applications to unfolded proteins. The determination of coupling constants for the peptide chain using 1D ¹H, or 2D and 3D ¹H-¹⁵N correlation spectroscopy is often hampered by extensive resonance overlap when dealing with flexible, disordered proteins. In the experiment detailed here, the overlap problem is largely circumvented by recording ¹H-¹³C′ correlation spectra, which demonstrate superior resolution for unfolded proteins. J-coupling constants are extracted from the peak intensities in a pair of 2D spin-echo difference experiments, affording rapid acquisition of the coupling data. In an application to the cytoplasmic domain of human neuroligin-3 (hNlg3cyt) data were obtained for 78 residues, compared to 54 coupling constants obtained from a 3D HNHA experiment. The coupling constants suggest that hNlg3cyt is intrinsically disordered, with little propensity for structure.     

C型产气荚膜梭菌α、β_1毒素基因的融合

利用PCR技术,从C型产气荚膜梭菌染色体DNA中扩增出α和β1毒素基因,通过分离、纯化、内切酶酶切、连接和转化,构建了含αβ1融合基因表达质粒重组菌株BL21(DE3)(pETXAB1)。经酶切鉴定和核苷酸序列测定证实,构建的重组质粒pETXAB1含有αβ1融合基因,且基因序列和阅读框架均正确。经ELISA检测,重组菌株表达的αβ1融合蛋白能够被α、β1毒素抗体识别。免疫实验结果表明,αβ1融合蛋白免疫的小鼠可以抵抗1MLD的C型产气荚膜梭菌C5944毒素攻击,表明构建的重组菌株可以作为预防仔猪红痢基因工程亚单位苗的候选菌株。     

Polyspecific associations of <Emphasis Type="Italic">Cercopithecus campbelli</Emphasis> and <Emphasis Type="Italic">C. petaurista</Emphasis> with <Emphasis Type="Italic">C. diana</Emphasis>: what are the costs and benefits?

Polyspecific associations (PSA) are common in many African primate communities, including the diurnal primates at Taï Forest, Côte d’Ivoire. In this paper I use data on the PSA of two forest guenons, Campbell’s (Cercopithecus campbelli) and lesser spot-nosed monkeys (C. petaurista), with Diana monkeys (C. diana) and other primates to clarify interspecific relationships during 17 months including a 3-month low-fruit period. I analyzed association in relation to fruit availability and measured forest strata use for C. campbelli and C. petaurista when alone and in associations with and without C. diana. I also measured predator risk and reactions to potential predators. C. campbelli and C. petaurista had high association rates with C. diana monkeys, and fruit availability did not influence association rates. C. campbelli and C. petaurista used higher strata when in association with C. diana than when alone, but they used even higher strata when associated with other primates without C. diana. This suggested that C. diana competitively exclude C. campbelli and C. petaurista from higher strata. There were relatively large numbers of potential predators, and C. diana were usually the first callers to threatening stimuli, suggesting that antipredator benefits of association with C. diana outweighed the competitive costs. C. campbelli spent more time in association with C. diana than C. petaurista did and appeared to be more reliant on C. diana for antipredator benefits. C. petaurista were less reliant on C. diana because of a cryptic strategy and may have associated less in some months because of high chimpanzee (Pan troglodytes) presence.     

Peak fitting in 2D <Superscript>1</Superscript>H–<Superscript>13</Superscript>C HSQC NMR spectra for metabolomic studies

A modified Lorentzian distribution function is used to model peaks in two-dimensional (2D) ¹H–¹³C heteronuclear single quantum coherence (HSQC) nuclear magnetic resonance (NMR) spectra. The model fit is used to determine accurate chemical shifts from genuine signals in complex metabolite mixtures such as blood. The algorithm can be used to extract features from a set of spectra from different samples for exploratory metabolomics. First a reference spectrum is created in which the peak intensities are given by the median value over all samples at each point in the 2D spectra so that ¹H–¹³C correlations in any spectra are accounted for. The mathematical model provides a footprint for each peak in the reference spectrum, which can be used to bin the ¹H–¹³C correlations in each HSQC spectrum. The binned intensities are then used as variables in multivariate analyses and those found to be discriminatory are rapidly identified by cross referencing the chemical shifts of the bins with a database of ¹³C and ¹H chemical shift correlations from known metabolites.     

<Superscript>1</Superscript>H, <Superscript>13</Superscript>C,and <Superscript>15</Superscript>N resonance assignments for the pro-inflammatory cytokine interleukin-36α

Interleukin-36α (IL-36α) is a recently characterised member of the interleukin-1 superfamily. It is involved in the pathogenesis of inflammatory arthritis in one third of psoriasis patients. By binding of IL-36α to its receptor IL-36R via the NF-κB pathway other cytokines involved in inflammatory and apoptotic cascade are activated. The efficacy of complex formation is controlled by N-terminal processing. To obtain a more detailed view on the structure function relationship we performed a heteronuclear multidimensional NMR investigation and here report the ¹H, ¹³C, and ¹⁵N resonance assignments for the backbone and side chain nuclei of the pro-inflammatory cytokine interleukin-36α.