1 Comparison of the ITS and the EF1-α phylogenetic trees: The phy

1 Comparison of the ITS and the EF1-α phylogenetic trees: The phylograms resulted from RAxML analysis of a) ITS and b) EF1-α regions. The ML, MP bootstrap values ≥70 %, bayesian PP ≥ 0.75 are indicated above the branches. The trees are rooted with Diaporthe citri

(AR3405). The sequences of Di-C005/1-10 (green) were obtained from Santos et al. 2010. Ex-type and ex-epitype cultures are in bold Single gene analyses and comparison The ITS and EF1-α sequence alignment consisted of 548 and 369 characters respectively, with 78 isolates including the outgroup taxa. selleck products Phylogenetic trees obtained from maximum likelihood (ML), parsimony (MP), and Bayesian (BI) analysis were compared for the placement of each isolate, topology of the tree and clade stability. The topology of the ML tree inferred from RAxML was identical

to BI and MP trees with reference to the major subclades and is presented check details as Fig. 1 Alignment properties and model selections are shown in Table 2. The ITS phylogeny has limited resolution within the species complex often resulting in an inconclusive branching order and lack of bootstrap support at the internodes, resulting in two major clusters. Analysis of each region of the ITS sequences of Diaporthe eres with the reference

annotated sequence (KC343073) revealed an approximately 176 bp span for ITS1 and 161 bp for ITS2 region with the intermediate 5.8 s rDNA partition https://www.selleckchem.com/products/PD-0325901.html spanning approximately 157 bp. The differences within two ITS1 clusters were consistent although the two clusters were not completely congruent with the ITS2 region. We obtained two different isolates from  a single ascospore and conidium (AR5193, AR5196) derived from two twigs of Ulmus collected at the same time from the same individual tree in Germany, where the field collections were made. Both of these isolates were determined to be D. eres based on morphology of the asexual and sexual morphs. However, the single ascospore-derived isolate Phosphatidylinositol diacylglycerol-lyase (AR5193) and the single conidium-derived isolate (AR5196) had different ITS sequences and were placed in different major groups in the ITS phylogenetic tree (Fig. 1). However, they were determined to be the same species based on EF1-α and all other genes. Inspection of the ITS alignment also revealed that isolates can share similarity in the ITS1 and ITS2 regions both within and between species in this complex. The ITS1 region of Diaporthe vaccinii is identical to most of the isolates identified as D. eres.

A multivariate distance measure (a self-standardizing Gower metri

A multivariate distance measure (a self-standardizing Gower metric) is used to quantify divergence amongst PFTs and also amongst PFT assemblages (Gillison and Carpenter 1997; Gillison 2002). For each sample, PFT richness can be expressed either as the number of species CHIR99021 recorded per PFT (species weighted) or as the total number of PFTs recorded independently of species (unique). Similarly, PFEs can be measured summatively either by unique

PFTs (PFT–weighted PFEs), or species for each OICR-9429 manufacturer sample plot. We used public domain VegClass© software (Gillison 2002) to compile and tabulate data. In the field each 40 × 5 m transect comprised eight contiguous, 5 × 5 m quadrats from which the data were analysed, again using VegClass©, to construct species:area and PFT:area curves as a measure of local sampling

efficiency (Gillison 2006; Tables S4, S5, S20, Online Resources). Vegetation structure comprised mean canopy height and projective cover, percent basal area for all woody plants using a Bitterlich method, Domin scale cover for woody plants and bryophytes, and mean furcation index (Gillison 2002, 2006). In addition, VegClass© was used to generate a plant functional complexity (PFC) index (Appendix S1, Online Resources). Cobimetinib clinical trial The PFC value is estimated as the total length of a minimum spanning tree distance passing through all PFT combinations (Gillison and Carpenter 1997; Gillison 2000). The PFC index provides a comparative measure of PFT variability, for example where two or more plots have the same PFT richness but differ in composition. Vertebrate fauna Ornithologists (two persons per site visit) identified birds by calls, referenced to standard audio

discs, during 90 min observations at dawn and dusk. Capture by mist netting was Fossariinae also undertaken during daylight hours. Small mammals were sampled in baited traps, larger mammals by direct observations (similar to those for birds) and from fresh droppings. Observations were made within an approximate 200 m radius of each base transect (Tables S8–S10, Online Resources). Full details of methods and critiques are given in Gillison (2000). Invertebrate fauna (termites) Methods used to assess termites differed somewhat between the two regions, although the area sampled (200 m2) was the same in both cases. In Sumatra, termites were extracted from mounds, plant litter and soil along a 100 m line transect of 2 m width adjacent to the vegetation transect, with one person-hour of sampling effort for each 5 m of the transect (Swift and Bignell 2001; Jones et al. 2003). In Mato Grosso, termites were sampled intensively mainly aboveground by two people for 2 h inside the vegetation transects (base transects).

The actin microfilament cytoskeleton is

The actin microfilament cytoskeleton is involved in cellular processes, determining cell shape, and cell attachment. As the cell adheres to a substrate material, filopodia are formed. They are moved into place by actin acting upon the plasma membrane. Our results showed that the degree of cytoskeletal organization strongly increased on PLGA/nHA-I nanofiber scaffolds (Figure 9c) contrary to the PLGA/nHA composite (Figure 9b) and pristine PLGA nanofiber scaffolds (Figure 9a). The organized cytoskeleton can exert forces onto the substratum, thus orientating the matrix. This ordered extracellular matrix can in turn orientate

with the cytoskeleton of other cells that come into contact with it, ultimately creating a large-scale organization. Figure 8 Proliferation of osteoblast cells cultured on the pristine PLGA, PLGA/nHA, and PLGA/nHA-I nanofiber scaffolds. For 2 days click here as determined by a Brdu assay. Figure 9 Confocal laser scanning selleck chemicals micrograph of osteoblasts. Actin (red). Nucleus (blue). (a) Pristine PLGA, (b) PLGA/nHA, and (c) PLGA/nHA-I after selleck inhibitor 3 days of incubation. Alizarin red staining Differentiation of osteoblastic cells is one of the most important parameters for confirming osteogenesis of osteoblastic cells cultured

on the scaffolds [37]. To confirm osteogenesis, alizarin red staining is considered as one of the marker specific for differentiation of osteoblastic cells [38]. Figure 10a,b,c shows that osteoblastic cells underwent osteogenesis process on all of the scaffolds. The osteogenesis process was determined from the appearance of the red color, which is an indicator of calcium production

by osteoblastic cells. More cells were differentiated on the PLGA/nHA-I composite nanofiber scaffold (Figure 10c, dark red color) compared to the PLGA/nHA composite (Figure 10b, light red color) and pristine PLGA (Figure 10a, grayish color) nanofiber scaffolds. These results suggest that grafting of insulin on the nHA surface accelerated the differentiation of osteoblastic cells [38]. Figure 10 Alizarin red staining of osteoblast cells cultured for 15 days. On (a) PLGA, (b) PLGA/nHA, and (c) PLGA/nHA-I nanofiber scaffolds. Von Kossa assay Figure 11 illustrates the results of the Von Kossa assay performed on the PLGA/nHA-I, PLGA/nHA composite, and Pregnenolone pristine PLGA nanofiber scaffolds. Bone nodules are considered to be one of the markers specific to osteoblastic cell differentiation. In the Von Kossa assay, the calcified area is stained as black spot. The results obtained from the Von Kossa assay suggest that more bone nodules were formed on the PLGA/nHA-I (Figure 11c) contrary to the PLGA/nHA (Figure 11b) composite and pristine PLGA (Figure 11a) nanofiber scaffolds [1]. The Von Kossa assay results clearly suggested that insulin triggered and accelerated osteoblastic cell differentiation (Figure 11c) [20].

For example, offering bone densitometry to women treated with bis

For example, offering bone densitometry to women treated with bisphosphonates has been found to be Acalabrutinib mouse associated with a lower probability of discontinuation [35], although there is no evidence that the BMD change, if any, is directly related to anti-fracture effectiveness. Moreover, the impact of offering densitometry

may be limited, since the largest loss of patients ATM Kinase Inhibitor chemical structure to treatment occurs within the first 6 months of prescription, an interval in which bone densitometry is neither recommended nor proposed. Others have suggested the utility of biochemical markers to provide patients with feedback on treatment effectiveness [36], but such markers are not determined in routine clinical practice. Improving patient communication on the importance of treatment and use of reminder systems

is clearly important. For example, Briot et al. [37] reported that osteoporotic women starting therapy with a parathyroid hormone analogue Gilteritinib research buy who enrolled in an education and follow-up programme could achieve 15-month persistence rates >80%. It should be noted that non-persistence, as defined in this and other studies, is not necessarily equivalent to treatment discontinuation, as patients may lapse and then resume treatment after a ‘drug holiday’ of variable duration. Given the long half-life of bisphosphonates in bone tissue, such women may continue to gain some benefit from their treatment even if they go on ‘drug holidays’. Although such behaviour was not studied in detail here and would merit evaluation in a study with considerably longer follow-up duration, it is unlikely that the differences in persistence observed in our study could be accounted

for by ‘drug holidays’, as the proportion of women who did this was relatively low and similar between the two cohorts. An important potential confounding factor in any comparison of adherence between different treatment Calpain regimens is that patients prescribed one or other regimen may be different. Indeed, in the present study, we found, for example, that women prescribed monthly bisphosphonates tended to be younger and less likely to have already experienced an osteoporotic fracture. In contrast, they were more likely to have undergone bone densitometry. This probably relates to the fact that the women could either receive a diagnosis on the basis of BMD or on the basis of fracture. Since the proportion of women with previous fractures was lower, they were de facto more likely to have received a diagnosis on the basis of low BMD, accounting for the higher use of bone densitometry in this group. Women in the monthly group were also more frequently receiving multiple comedications, which may have been an incentive for their physicians to prescribe them less frequently administered bisphosphonates. These factors may themselves influence treatment adherence and it is important that they be taken into account in any adherence study.

The accuracy of secondary data sources in capturing cases has bee

The accuracy of secondary data sources in capturing cases has been explored with results varying upon the source LB-100 mw selected Alisertib cost and gold standard used [6–9]. In the study from Penberthy et al., the Virginia Cancer Registry (CR) and a statewide

hospital discharge file (HDF) were both tested for accuracy in correctly identifying a cancer and its site of origin. Data from inpatient medical records were used as the gold standard. Based on the conclusions stated, nor the CR neither the HDF was sufficient independently to allow the complete capture of incident cancer cases. However, HDF accuracy in capturing incident cancer cases was high, with the overall positive predictive value being 94% and site specific values ranging from 86% (cervix) to 98% (breast) [9]. In Italy, the government supports cancer surveillance throughout a network of population-based local CRs included in the Italian Association of Cancer Registries (AIRTUM). Currently, the AIRTUM covers 33.8% of the Italian population, namely 19 million people out of 61 million inhabitants. A notable disproportion in CRs coverage exists among Northern, Central and Southern areas of Italy (i.e., 50.2%, 25.5% and find more 17.9%, respectively) [10]. We have previously underlined the need to integrate data from the Italian CRs with additional sources and identified the National

Hospital Discharge Records (NHDRs) as a potential tool [11]. In this study we aimed to evaluate the burden of breast cancer in Italian women by analyzing data from the NHDRs through a non-model-based methodology with a specific focus on major surgical procedures. Compared to our previous work, data have been updated to reflect a larger time window (2001–2008 vs. 2000–2005) and methods refined to overcome some of the limitations from our previous study. Materials and methods Data source We used the NHDR database which includes records

from all the Italian public and private hospitals. Data were made available by the Italian Ministry of Health relatively to the time frame between 2001 and 2008. These data were subject to a systematic quality assessment performed at a Regional and central level. The matching with the National Institute for Statistics (ISTAT) by social security code showed a percentage of correct Clomifene linkage increasing from 95.6% in 2001 (50,921 records matched out of 53,226) to 99.8% in 2008 (58,367 records matched out of 58,492) [12, 13]. The years 1999 and 2000 were excluded due to incomplete data. Breast cancer cases were identified on the basis of the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) [14, 15]. We considered patients diagnosed with invasive breast cancer (i.e., malignant neoplasm of breast, ICD-9CM codes: 174.0-174.9 and 175.0-175.9). Data related to patients with in situ breast carcinoma (ICD-9-CM major diagnosis 233) were also included.

As shown in Table 1, the computational results

for the st

As shown in Table 1, the computational results

for the structural parameters a, c, d ep, d ap, c/a, and 2θ are summarized together with the reported SC79 experimental values [28] and previous theoretical results [29]. The lattice parameters obtained in this work are in good agreement with the experimental data, and the SBI-0206965 deviation is less than 1.06% along the a-axis or 0.5% along the c-axis. In comparison with the previous theoretical results reported in [29], our calculation results are more accurate, which verifies that the calculating method and models in this work are reliable and the calculated results are authentic. Table 1 Optimized structural parameters for anatase TiO 2 compared

with experimental and previous theoretical results   Experimental This work Literature [29] Result Deviation (%) Result Deviation (%) a/Å 3.785 3.745 -1.06 3.692 -2.46 c/Å 9.514 9.466 -0.50 9.471 -0.45 d ep/Å 1.934 1.914 -1.03 1.893 -2.12 d ap/Å 1.978 1.969 -0.46 1.948 -1.52 c/a 2.513 2.528 0.56 2.566 +2.11 Electronic structure In order to conveniently investigate the electronic structures of transition metal-doped anatase TiO2, we set the same k-points mesh to sample the first Brillouin zone for pure and transition metal-doped models. The calculated band gap of pure anatase TiO2 is 2.21 eV as shown in Figure 2. BTSA1 supplier The conduction band minimum (CBM) is located at G, while the valence band maximum (VBM) is located near X. So, the anatase TiO2 can be considered as an indirect band gap semiconductor. www.selleck.co.jp/products/PD-0332991.html The value of band gap is consistent with the reported results [29], but is underestimated compared with the experimental value (E g = 3.23 eV), due to the limitation of DFT: the discontinuity in the exchange correlation potential is not taken into account

within the framework of DFT. However, our discussions about energy gap will not be affected because only the relative energy changes are of concern. Figure 2 Calculated band structure of pure TiO 2 . The total density of states (TDOS) and partial density of states (PDOS) of transition metal-doped anatase TiO2 in comparison with those of pure anatase TiO2 are shown in Figures 3 and 4, which are treated by Gaussian broadening. The band gap is defined as the separation between the VBM and CBM. The TDOS shape of transition metal-doped TiO2 becomes broader than that of pure TiO2, which indicates that the electronic nonlocality is more obvious, owing to the reduction of crystal symmetry [19]. The transition metal 3d or 4d states are somewhat delocalized, which contributes to the formation of impurity energy levels (IELs) by hybridizing with O 2p states or Ti 3d states. Such hybrid effect may form energy levels in the band gap or hybrid with CBM/VBM, providing trapping potential well for electrons and holes.

In the present work, we

In the present work, we PS-341 purchase made 3-MA price efforts to improve photocatalytic carbon dioxide conversion rates by the following strategies: (1) employ high surface area titania nanotube arrays, with vectorial charge transfer, and

long-term stability to photo and chemical corrosion; and (2) modify the titania to enhance the separation of electron-hole pairs by incorporating nitrogen and vanadium. This article reports the synthesis, morphologies, phase structures, and photoelectrochemical of self-organized V, N co-doped TiO2 nanotube arrays as well as the effect of V and N co-doping on photocatalytic reduction performance of CO2 into CH4. Methods Fabrication of V, N co-doped TiO2 nanotube arrays V, N co-doped TiO2 nanotube arrays (TNAs) were fabricated by a combination of electrochemical anodization and hydrothermal reaction. Firstly, highly ordered TNAs were fabricated on a Ti substrate in a mixed electrolyte solution of ethylene glycol containing NH4F and deionized water by a two-step electrochemical anodic oxidation process according to our previous reports [11]. Interstitial nitrogen

species were formed in the TNAs due to the electrolyte containing NH4F [12]. Then, the amorphous TNAs were annealed at 500°C Go6983 cost for 3 h with a heating rate of 10°C/min in air ambience to obtain crystalline phase. We denoted these single N-doped TNAs samples as N-TiO2. V, N co-doped TNAs were prepared by a hydrothermal process. As-prepared N-TiO2 samples were immersed in Teflon-lined autoclaves (120 mL, Parr Instrument, Moline, IL, USA) containing approximately 60 mL of NH4VO3 aqueous solution (with different concentration 0.5, 1, 3, and 5 wt.%) as the source of both V and N. All samples were hydrothermally treated at 180°C for 5 h and then naturally cooled down to room temperature. Finally, all samples were rinsed with deionized water

and dried under high purityN2 stream. The corresponding samples (0.5%, 1%, 3%, and 5%) were labeled as VN0.5, VN1, VN3, and VN5. For control experiment, sample denoted as VN0 was prepared by the previously mentioned hydrothermal process in 60 mL pure water without NH4VO3 addition. Characterization Surface morphologies of all samples were observed click here with field emission scanning electron microscope (FESEM, JEOL JSM-7001 F, Akishima-shi, Japan) at an accelerating voltage of 15 kV. Phase structures of the photocatalysts were analyzed by X-ray diffraction (XRD) analysis on an X’Pert Philips (Amsterdam, The Netherlands) diffractometer (Cu Kα radiation, 2θ range, 10° to 90°; step size, 0.08°). Chemical state and surface composition of the samples were obtained with an Axis Ultra X-ray photoelectron spectroscope (XPS, Kratos, Manchester, UK; a monochromatic Al source operating at 210 W with a pass energy of 20 eV and a step of 0.1 eV was used). All binding energies (BE) were referenced to the C 1 s peak at 284.8 eV of the surface adventitious carbon.


(all p > 0 05) (Figure 3) To confirm the hypoth


(all p > 0.05) (Figure 3). To confirm the hypothesis that this effect was not specific to strain ATCC90028, we tested three unrelated clinical strains and found that HS had the same effect on all three clinical strains as well (data not shown). Figure 3 Effect of human serum on planktonic growth of C. albicans. Twenty-four-hour selleck inhibitor growth curves showing 50% HS, 50% heat-inactivated HS, and 50% proteinase K-treated HS against C. albicans ATCC90028 in RPMI 1640. Symbols: ◆, growth control; ■, 50% HS; ▲, 50% heated HS; ×, 50% proteinase K-treated HS. Effect of human serum on check details expression of adhesion-related genes To elucidate the potential molecular mechanism behind the ability of HS to prevent growth of C. albicans biofilms, total RNA was isolated from biofilms of four C. albicans strains grown in RPMI 1640 medium with or without 50% HS at three time points (60 min, 90 min and 24 h). The expression levels of specific genes that were previously implicated in mediating the adhesion of C. albicans cells were determined by real-time RT-PCR. HS had varying effects on different genes in different selleckchem tested strains

(data not shown), but the general trend of these genes was consistent. HS down-regulated the expression of the adhesion-related genes ALS1 (1.1 to 3.0-fold) and ALS3 (1.5 to 3.8-fold), but up-regulated the expression of the hypha-related genes HWP1 (1.1 to 2.4-fold) and ECE1 (1.1 to 4.2-fold) at all three time points (Figure 4). Particularly, expression levels of ALS1 (2.5 and 3.0-fold) and ALS3 (3.7 and 3.8-fold) showed significant differences at both 90 min and 24 h (p < 0.05 or p < 0.01) (Figure 4B,C). Only at the 90-min time point were the transcription levels Rebamipide of HWP1 (2.4-fold) and ECE1 (4.2-fold) significantly higher (p < 0.05 or p < 0.01) (Figure 4B). The transcription level of BCR1 was

significantly higher at 90 min (3.3-fold, p < 0.01) (Figure 4B), but BCR1 levels were significantly lower at both 60 min (2.8-fold, p < 0.05) and 24 h (5.6-fold, p < 0.01) (Figure 4A,C). Figure 4 Expression of C. albicans adhesion-related genes. Candida albicans cells were incubated in the absence or presence of HS (50%) and the expression of target genes was determined by RT-PCR. Housekeeping gene ACT1 was used as an internal control. Each gene was assessed in triplicate, and the experiment itself was performed in biologic duplicate. The data shown here are a representative graph of strain ATCC90028. A) Expression of genes ALS1, ALS3, HWP1, ECE1, and BCR1 following the treatment with HS for 60 min. B) Different expression of the target genes following treatment with HS for 90 min. C) Target gene expression level following treatment with HS for 24 h. Discussion To make the transition from a commensal organism to a systemic pathogen, C. albicans must first enter the bloodstream.

Infect Immun 2007, 75:5282–5289 PubMedCrossRef 14 Voth DE, Howe

Infect Immun 2007, 75:5282–5289.PubMedCrossRef 14. Voth DE, Howe D, Heinzen RA: Coxiella burnetii Inhibits Apoptosis in Human THP-1 Cells and Monkey Primary PLX4720 Alveolar Macrophages. Infect Immun 2007, 75:4263–4271.PubMedCrossRef 15. Howe D, Mallavia LP: Coxiella burnetii Exhibits Morphological Change and Delays Phagolysosomal Fusion after Internalization by J774A.1 Cells. Infect Immun 2000, 68:3815–3821.PubMedCrossRef 16. Romano PS, Gutierrez MG, Berón W, Rabinovitch M, Colombo MI: The autophagic pathway is actively modulated by phase II Coxiella burnetii to efficiently replicate in the host cell. Cellular Microbiology 2007, 9:891–909.PubMedCrossRef 17. Luhrmann A, Roy

CR: Coxiella burnetii inhibits activation of host cell apoptosis through a mechanism that involves preventing cytochrome c release from mitochondria. Infect Immun

2007, 75:5282–5289.PubMedCrossRef 18. Voth DE, Heinzen RA: Sustained activation of Akt and Erk1/2 is required for Coxiella burnetii antiapoptotic activity. Infect Immun 2009, 77:205–213.PubMedCrossRef 19. Voth DE, Howe D, Beare PA, Vogel JP, Unsworth N, Samuel JE, Heinzen RA: The Coxiella burnetii Ankyrin Repeat Domain-Containing Protein Family is Heterogeneous with C-terminal Truncations that Influence Dot/Icm-Mediated Secretion. J Bacteriol 2009, JB.01656–01608. 20. Morgan JK, Luedtke selleck products BE, Shaw EI: Polar localization of the Coxiella burnetii type IVB secretion system. FEMS Microbiology Letters 2010, 305:177–183.PubMedCrossRef 21. Seshadri R, Paulsen IT, Eisen JA, Read TD, Nelson KE, Nelson WC, Ward NL, Tettelin H, Davidsen TM, Beanan MJ, et al.: Complete genome sequence of the Q-fever pathogen Coxiella burnetii . Proceedings of the National Academy of Sciences of the NADPH-oxidase inhibitor United States of America 2003, 100:5455–5460.PubMedCrossRef 22. Beare

PA, Unsworth N, Andoh M, Voth DE, Omsland A, Gilk SD, Williams KP, Sobral BW, Kupko JJ III, Porcella SF, et al.: Comparative Genomics Reveal Extensive Transposon-Mediated Unoprostone Genomic Plasticity and Diversity among Potential Effector Proteins within the Genus Coxiella. Infect Immun 2009, 77:642–656.PubMedCrossRef 23. Shannon JG, Heinzen RA: Infection of human monocyte-derived macrophages with Coxiella burnetii . Methods Mol Biol 2008, 431:189–200.PubMedCrossRef 24. Howe D, Shannon JG, Winfree S, Dorward DW, Heinzen RA: Coxiella burnetii phase I and II variants replicate with similar kinetics in degradative phagolysosome-like compartments of human macrophages. Infect Immun 2010, 78:3465–3474.PubMedCrossRef 25. Bernardo A, Bai G, Guo P, Xiao K, Guenzi A, Ayoubi P: Fusarium graminearum -induced changes in gene expression between Fusarium head blight-resistant and susceptible wheat cultivars. Functional & Integrative Genomics 2007, 7:69–77.CrossRef 26.

The uptake of phosphorus by brucite during hydrothermal circulati

The uptake of phosphorus by brucite during hydrothermal circulation has lead Bradley et al. (2009) to propose that the utilization of glycosyl head groups instead of phosphatidyl head groups by bacteria constitutes a strategy for conservation of scarce phosphorus. Condensed Niraparib phosphates have stronger binding energies to hydroxide minerals like brucite than orthophosphate (Arrhenius et al. 1997), in the same way as polynucleotides bind stronger than mononucleotides (Holm et al. 1993). This means that the condensed phosphates have the potential to (outcompete orthophosphate and) concentrate on the mineral surfaces. Inorganic pyro- and polyphosphates are used for energy transfer

and storage in many microorganisms, and it has been proposed that the chemical energy stored in this type of inorganic molecules has been used by primitive forms of life on the early Earth (Baltscheffsky and Baltscheffsky 1994). Despite the Saracatinib general scarcity of phosphorus on Earth, such compounds could have been produced in the prebiotic world by several possible pathways. Prebiotic Pyrophosphate Formation Wheat et al. (1996) have estimated that ridge-axis and ridge-flank hydrothermal processes click here in the ocean floor in combination today remove about 50% of the global input of dissolved phosphorus from rivers into oceanic crust. Bodeï et al. (2008) have shown that phosphate is

strongly enriched as authigenic phases in the basal sedimentary layer on top of the basaltic basement, the source of phosphorus being primarily the basalts underneath. Under standard temperature conditions (25°C), apatite (Ca-orthophosphate) forms as a single phase at pH 9 or higher in a sterile seawater medium. However, in the pH range 7–9 primarily the mineral whitlockite (Ca18Mg2H2(PO4)14 is formed under the same temperature conditions (Gedulin and Arrhenius 1994). Preformed crystals of apatite placed in a neutral or slightly alkaline sterile solution with the Mg/Ca ratio of seawater

convert to whitlockite. Abbona and Franchini-Angela (1990) have also shown that amorphous calcium phosphate converts to whitlockite above the Mg/Ca molar ratio 0.8. It has second long been known that hydrogen containing phosphates like whitlockite and newberyite at heating react to form pyrophosphate and water (Sales et al. 1993; Gedulin and Arrhenius 1994). Low water activity in the system promotes the pyrophosphate formation (Russell and Hall 1997). The phosphate condensation is due to the protonation of the phosphate. At heating, the hydrogen reacts with one of the oxygen ligands of the phosphorus and leaves as water. As a response, the structure of the orthophosphate rearranges to form one or more anhydride P-O-P bonds (Arrhenius et al. 1997), i.e. the backbone of condensed phosphates like pyrophosphate. A seemingly alternative pathway for pyrophosphate formation would be oxidation of the phosphide mineral schreibersite (Fe,Ni)3P.