Brill, Boston, pp 25–50 Guthrie SE (1997) Anthropomorphism: a def

Brill, Boston, pp 25–50 Guthrie SE (1997) Anthropomorphism: a definition and theory. In: Mitchell RW, Thompson NS, Miles HL (eds) Anthropomorphism, anecdotes, and animals. State University of New York Press, Albany, pp 50–58 Harley, W (Producer) (2005, 10 January) Vanuatu—Saving Nemo [online documentary]. ABC Australia: Journeyman Pictures. Accessed online: http://​www.​journeyman.​tv/​18050/​short-films/​saving-nemo.​html and http://​www.​youtube.​com/​watch?​v=​rC8rkMjIZAk Ikeda T, Asasno M, Matoba Y, Abe G (2004) Present status of invasive alien raccoon and its impact in Japan. Glob Environ Res

8:125–131 Ingold T (1994) Introduction. In: Ingold T (ed) What is an animal? Routledge, London, pp 1–16 Ingold T (2000) The perception of the CP673451 cell line environment. Essays on living, dwelling and skill. Routledge, London Kaufman L AZD5582 molecular weight (2012) When babies don’t fit plan, question for zoos is, now what? The New York Times, Science Section August 2. Accessed online: http://​www.​nytimes.​com/​2012/​08/​03/​science/​zoos-divide-over-contraception-and-euthanasia-for-animals.​html?​hp. Kennedy JS (1992) The new anthropomorphism. Cambridge University Press, CambridgeCrossRef Knight J (2005) Feeding Mr. Monkey: cross-species food “exchange” in Japanese

monkey parks. In: Knight J (ed) Animals in person: cultural perspectives on human-animal intimacies. BERG, Oxford, pp 231–253 Kogut T, Ritov I (2005) The “identified victim” effect: an identified group, or just a single individual? J Behav Decis Making 18:157–165CrossRef Kotler P, Armstrong G (2012) Principles of marketing. Pearson Prentice Hall, Upper Saddle River Krauss W (2005) Of otters and humans: an approach to the politics of nature in terms of rhetoric. Cons Soc 3(2):354–370 Lancendorfer KM, Atkin JL, Reece BB (2008) Animals in advertising: love dogs? Tolmetin Love the ad! J Bus Res 61:384–391CrossRef Lorimer H (2006) Herding memories of humans

and animals. Environ Plan D: Soc Space 24:497–518CrossRef Lorimer J (2007) Nonhuman charisma. Environ Plan D: Soc Space 25:911–932CrossRef Manfredo MJ, Fulton DC (2008) The biological context of wildlife values: are there etchings on the slate? In: Manfredo MJ (ed) Who cares about wildlife?. Springer, New York, pp 29–48CrossRef Milton K (2005) Anthropomorphism or egomorphism? The perception of nonhuman persons by human ones. In: Knight J (ed) Animals in person: cultural perspectives on human-animal intimacies. BERG, Oxford, pp 255–271 Mitchell RW (1997) Anthropomorphic anecdotalism as method. In: Mitchell RW et al (eds) Anthropomorphism, anecdotes, and animals. SUNY Press, Albany, pp 151–169 Mithen S (1996) The prehistory of the mind. Thames and Hudson Ltd., London Nicholls H (2011) The art of conservation. Nature 472:287–289PubMedCrossRef Nowak KL, Rauh C (2008) Choose your “buddy icon” carefully: the influence of avatar androgyny, anthropomorphism and credibility in online interactions.

Open Access This article is distributed under the terms of the Cr

Open Access This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. Glossary Co-option Reuse of existing genetic components, metabolic reactions, or signaling modules in diverse biological systems, such as tumors, for instance, discharging in the evolution of patterns of dysregulated transcription factors. Evolvability The capacity of an organism or a biological system to generate new heritable phenotypes. Therapeutical

modularly induced evolutionary steps advance this definition: Modularity may allow retrospectively established spaces for primarily none-heritable evolutionary developments, if modular events (therapy) are implemented. Modularity In the present context, modularity is a formal pragmatic communicative systems concept, describing the degree TEW-7197 PHA-848125 mouse and specificity to which systems objects (cells, pathways, etc.) may be communicatively separated in a virtual continuum and

recombined and rededicated to alter the validity and denotation of communication processes in the tumor. Modular communication (therapies) The function is to configure the coherence between the validity and denotation of communication processes. Modular therapies may supplement prepositional aspects of communication, i.e. the presence of the tumor’s living world by normative aspects, namely by therapy-derived yes or no statements (‘know that’). Risk-absorbing background knowledge This knowledge constitutes the validity of informative intercellular processes, which is the prerequisite for therapeutic success. Background knowledge about the tumor’s living world is subjected to other conditions of scientific comprehension: Intentional ways fail to describe risk-absorbing PI3K inhibitor knowledge, in which context-dependent knowledge about commonly administered reductionist therapy approaches is rooted.

After this second objectifying step (physicians as operators of tumor systems), the network of the holistic communicative activities turns out to be the medium through which the tumor’s living world is OICR-9429 purchase mirrored and generated. Tumor’s living world The living world comprises the tumor’s holistic communication processes, which we rely on in every therapy. The living world of morphologically defined tumor cell systems creates the term opposite to those idealizations, which originally constitute scientific (intentional) knowledge. The living world is uncovered by redeeming the validity of communicative tumor processes by implementing the modular knowledge of cellular and external environments (for instance for therapeutic requirements). Only with experimental or therapeutic experiences (modular therapies) is the tumor’s living world separated into categories of knowledge, for example, into modular systems.

2000), and the enhanced backflow of electrons in PS I after

2000), and the enhanced backflow of electrons in PS I after EPZ015938 research buy chilling

cucumber leaves in the light (Kim et al. 2001). We also wrote a book chapter on mechanisms and physiological roles of proton movements in thylakoids (Chow and Hope 2002). Unfortunately, my lab at Weston lasted only 7 years; the entire building and its contents were burnt in January 2003 in a major fire in which 500 houses and four lives were also lost. I moved back in the main ANU campus, setting up my lab from scratch inside a large shed. Alex moved some more equipment from Adelaide, including two analogue-to-digital converters and a program for data acquisition Lazertinib cell line written by him to replace the burnt commercial software. During and between his visits, we worked on the quantification of cyclic and linear electron flow in leaf segments in various conditions (Chow and Hope 2004a; Fan et al. 2007b, 2008; Jia et al. 2008), the putative variable proton pumping action of the cyt bf complex (Chow and Hope 2004b), the ratio of the two photosystems (Fan et al. 2007a), and rapid quantification of functional Photosystem II (Losciale et al. 2008), all assayed in leaves. In intact leaves, through simulation of electron transfer events around the cyt Foretinib bf complex by simultaneous solution of a package of linear differential equations

representing the kinetics, Alex obtained close similarity of measurement and prediction for kinetic changes of cyt b, P700 and the ECS, though the matching was less satisfactory for cyt f (Chow and Hope 2004b). Year after year, Alex continued to drive his car to and from Canberra, travelling more than 2,000 km

on each visit (occasionally issued with a fine for speeding). Unfortunately, Amobarbital he had to stop visiting when his lung cancer returned—an unjust punishment for someone who never smoked. (The photograph of Alex was taken in late October 2006, in my post-fire lab in “The Shed” during what turned out to be his last visit to Canberra.) Alex loved his overseas visits to colleagues whenever opportunities allowed. For example, in the photosynthesis field, his visit to Jim Barber’s lab in London (in 1970–1971) was the beginning of a change of direction from research in plant membrane ion transport to photosynthesis “about which he had almost everything to learn” (Hope 2004). Subsequently, in 1979–1980, Alex visited Jim Barber at Imperial College again while I was also a postdoc there, and David Walker in Sheffield University. Germany seemed to Alex to be also home to many researchers in Photosynthesis, so he had short collaborations with Wolfgang Haehnel in Münster (in 1986), Günter Hauska in Regensburg (in 1990) and Ulrich Schreiber in Würzburg (in 1990). Having visited Peter Mitchell in 1970, Alex returned to Bodmin in 1991, just 1 year before Mitchell’s death, this time working with Peter Rich.


28]. Hormones inhibitor A phylogenetic tree was reconstructed using the GTR model in FastTree 2.1 [41]. Phylogenetic analysis of 16S rRNA gene fragments from opportunistic bacteria was conducted using MEGA version 5 [45]. Fluorescence in situ hybridization (FISH) Bacteria grown in liquid M552 medium or bacteria directly from antennal samples were

fixed in 4% formaldehyde overnight at 4°C, washed twice with ice-cold PBS and used for fluorescence in situ hybridization (FISH) as previously described [21]. The samples were dehydrated in a graded ethanol series and mounted on microscope slides coated with poly-L-lysine (Kindler, Freiburg, Germany). FISH was done with the ‘Ca. Streptomyces philanthi’-specific oligonucleotide probe Cy3-SPT177 [21] or the general eubacterial probe Cy3-EUB338 [46]. Additionally, bacterial DNA was stained unspecifically with DAPI (4’, 6-diamidino-2-phenylindole). Bacteria were visualized using an AxioImager.Z1 microscope (Zeiss). LGK 974 Analysis of the symbionts’ nutritional requirements In order to assess nutrient requirements, bacteria grown in liquid Grace’s medium with 10% FBS were

seeded onto R2A agar (Sigma) or onto agarified Grace’s medium containing inorganic salts, vitamins and carbon sources (sucrose, glucose and fructose), as well as one of two different nitrogen sources: (i) peptones from casein (Serva) and tryptone (AppliChem) 5 g/L each, or (ii) ammonium chloride 1 g/L. Bacteria were incubated in 24-well plates as described

above. Antibiotic resistance PXD101 molecular weight assays In order to analyze antibiotic resistance, bacteria were grown in liquid Grace’s medium supplemented with the following antibiotics (final concentrations): ampicillin (100 μg/ml), penicillin G (100 μg/ml), chloramphenicol (25 μg/ml), streptomycin (50 μg/ml), gentamycin (50 μg/ml), kanamycin (50 μg/ml), rifampicin (50 μg/ml), tetracycline (15 μg/ml). Bacterial growth was assessed visually after two weeks of incubation at 28°C as described above, in comparison with control samples grown without antibiotics. Scanning electron Racecadotril microscopy (SEM) For the SEM analysis, bacteria were grown as colonies on agarified Grace’s medium at 28°C for 1 month and then incubated at 10-14°C for an additional three weeks. Agar blocks with bacterial colonies were cut out, fixed overnight with 2,5% glutaraldehyde in sodium cacodylate buffer (0.1 M, pH 7.0) and were dehydrated with ethanol in serially increased concentration, followed by critical point drying in a Leica EM CPD300 Automated Critical Point Dryer (Leica, Wetzlar, Germany).

However, previous reports have indicated that carotenogenesis may

However, previous reports have indicated that carotenogenesis may be regulated by some type of feedback mechanism, by which the relative proportion of astaxanthin regulates the total amount of carotenoids synthesized [27]. Given our observations, the feedback mechanism mediated by astaxanthin in the carotenoid biosynthesis pathway may involve regulatory mechanisms at the transcriptional level, and the presence and composition of pigments may affect the transcriptional response triggered by the addition of glucose to the medium. To test this hypothesis, we performed glucose addition experiments using homozygous mutant strains that are incapable of synthesizing astaxanthin.

The strains used were T-YBHH2 (crtYB – ), T-I21H1H (crtI -) and T-SHH2 (crtS – ), as described in a previous work [28]. First, we Z-VAD-FMK molecular weight determined that the response of grg2 and PDC expression to glucose was similar in all of the strains studied and Selleck MCC-950 did not depend on the synthesis of selleckchem pigments (data not shown). In contrast, different results were observed for the mutants of the carotenogenesis pathway genes. For the crtYB gene, the 6-fold repression of mature messenger observed in the wild-type strain in response to glucose completely disappeared and was replaced by a slight induction in both, the mutant that accumulates phytoene (crtI -) and

the mutant that accumulates β-carotene (crtS – ) (Figure 5a). However, the levels of alternative transcripts in both mutant strains exhibited a glucose-mediated decrease that was less than the one observed in the wild-type strain (Figure 5b). A similar phenomenon was observed for the crtI gene; both, the mutant incapable of synthesizing carotenoids (crtYB aminophylline – ) and the mutant that accumulates β-carotene (crtS – ) showed a complete lack of glucose repression of the mature transcript (Figure 5c) and a very diminished response of the alternative transcript levels (Figure 5d). Finally, in the case of the crtS gene, the slight repression by glucose observed

in the wild-type strain was replaced by a slight induction in the crtYB – and crtI – mutants (Figure 5e). These results indicate that the expression of the crtYB, crtI and crtS genes in response to the addition of glucose depends, at least in part, on the normal synthesis of astaxanthin or on the presence of this compound in the cell. Figure 5 Effect of glucose on the expression of carotenogenesis genes in mutant strains incapable of synthesizing astaxanthin. Strains: T-YBHH2 (crtYB-/-, white inverted triangle), T-I21H1H (crtI-/-, black square) and T-SHH2 (crtS-/-, white diamond). Levels of mRNA for mature crtYB (a), alternative crtYB (b), mature crtI (c), alternative crtI (d) and crtS (e) in glucose-treated cultures (20 g/l) were determined for each strain relative to the control.

2 2 Inclusion Criteria We included all subjects dispensed an ADHD

2.2 Inclusion Criteria We included all subjects dispensed an ADHD or asthma medication between 1 February 2011 and 31 January 2012 who had data available for at least 4 months prior to the first dispensing (index date), and whose pharmacies consistently supplied data to the LRx database during the entire study period. Each subject was followed for 18 months from his/her

index date. A subject who was dispensed ADHD and asthma medications could be a member of both cohorts. 2.3 Prescription/Dispensing Data We included all ADHD medications whose ingredients were approved by the US FDA for the treatment of ADHD. These were the stimulants amphetamine, dexmethylphenidate, dextroamphetamine, lisdexamfetamine, methamphetamine, and methylphenidate, and the non-stimulants PFT�� ic50 atomoxetine, clonidine, and guanfacine. The asthma medications included were inhaled bronchodilators, inhaled steroids, inhaled steroid/long-acting β agonist combinations, and oral leukotriene inhibitors. Asthma medications were used as a comparator because they are Savolitinib concentration frequently used by a population with roughly similar

demographic characteristics as the population using ADHD medications [12], including a large VX-689 chemical structure representation of children and young adults, and are not believed to be widely abused or diverted [13]. Subjects who were not dispensed any ADHD medication during the 4 months before their index date were considered ‘naive’. The 4-month

period, rather than a shorter period, was adopted to decrease the risk of misclassifying as naïve a subject who was receiving an ADHD medication during the school year but took a planned break in its use during 3 or 4 months of vacation (i.e. took a ‘drug holiday’). 2.4 Outcome We assessed the number of subjects with overlapping dispensings of medications prescribed by different prescribers, and the number of prescribers and number of pharmacies involved in those dispensings, during the 18 months of follow-up. For subjects Niclosamide with more than one event of multiple overlapping filled prescriptions, we selected the one event with the maximum number of overlapping prescriptions. Note that a prescriber can write more than one prescription for a given individual, therefore the total number of pharmacies making dispensings for that individual may exceed the number of prescribers. An overlap occurred when two or more dispensings of medications prescribed by different prescribers were active on the same day (i.e. a medication was dispensed during the days’ supply of another dispensed medication). The overlapping dispensings could be for the same or different ADHD or asthma medications.

These primers amplified a 226 bp band PCR products were analyzed

These primers amplified a 226 bp band. PCR products were analyzed by 1.5% agarose gel electrophoresis, and they were observed and photographed under ultraviolet light. Band intensities were STAT inhibitor analyzed by the Touching gel imaging system and compared with β-actin to calculate relative expression levels. Immunohistochemical method Tissue samples were stained with two different EPZ015938 mouse antibodies via immunohistochemical method according to conventional staining procedures. Negative and positive controls were run synchronously. For the positive control, CIN and CC tissues were replaced by normal cervical tissues, while for the

negative control, phosphate buffer substituted for the primary antibody. Paraffin sections were deparaffinized by routine methods, and antigen retrieval was achieved by microwave treatment. After blocking with serum, IGFBP-5 and cFLIP rabbit anti-human polyclonal antibodies were applied at a dilution of 1:50

and incubated overnight at 37°C. The samples were rinsed three times with PBS (pH 7.2) for 5 min each, then incubated with biotin-labeled goat anti-rabbit IgG for 15 min at 37°C, rinsed again, and incubated with Nutlin-3a horseradish peroxidase-conjugated streptavidin for 30 min at 37°C. Finally, the sections were rinsed, stained with DAB, re-stained by hematoxylin, dehydrated in an ethanol gradient, cleared in xylene, and fixed by neutral balata. Immunohistochemical assessment This semi-quantitative assay was conducted under a high power lens (×400) integrated with staining intensity and the percent of positive cells. The expression of IGFBP-5 and cFLIP proteins in the histocytes was mostly localized to the cytoplasm, which appeared brownish yellow and contained brownish yellow particles. More than 10 representative fields of each section were observed under high power before we evaluated the staining results. We looked for positive staining within the squamous Ergoloid epithelia

of the control group, in the CIN focus position of the CIN group, and in the cancer focus of the CC group. We scored for staining intensity (0: no color; 1: light yellow; 2: brownish yellow; 3: chocolate brown) and the percent of positive cells (0: < 5%; 1: 5 to 25%; 2: 26 to 50%; 3: 51 to 75%; 4: > 75%) separately, and the summation of the two gave the final score (-: 0–2; +: 3–4; ++: 5–6; +++: 7) [12]. Detection of high risk-HPV Hybrid capture II assay was applied to directly detect high risk-HPV DNA (American DIGENE Co.). Thirteen HPV subtypes (16/18/31/33/35/39/45/51/52/56/58/59/68) can be detected by this method. In this protocol, double-stranded DNA in the specimen is turned into single-stranded DNA, which is then combined with an RNA probe to form a DNA-RNA hybrid. This hybrid was fixed with a specific antibody, which was subsequently combined with an enzyme-conjugated secondary antibody.

1999) (Fig  4b, c), and understanding of the electronic structure

1999) (Fig. 4b, c), and understanding of the electronic structure of the His/B850 complexes is important for understanding the mechanism of exciton transfer over the BChl ring and the transfer rate from the B800 to the B850. Quantum ROCK inhibitor electronic delocalization couples to distortions of the protein-cofactor “smart” matrix to enhance the transfer rate from the B800 to the B850 in a robust process (Jang et al. 2007). On excitation with blue light, the B800 band is populated, and the transfer to the B850 takes place on a time scale of 0.7–3 ps (Grondelle and Novoderezhkin 2006). While the intraband B800 and

interband B800–B850 electronic coherences decay rapidly, the B850 intraband coherence lasts several picaseconds in a wavepacket that is delocalized over several B850 BChls. In order to probe the electronic and protonic states of axial histidines, MAS

NMR has been applied in conjunction with site-specific isotope labeling of histidine residues in LH2 complex (Alia et al. 2001, 2004). By means of 1D 15N MAS NMR, our group has shown that the τ nitrogen of β-His30 and α-His31 ligate to the Mg2+ of the B850 BChl a molecules. The hydrogen bonding status of the π nitrogen was reflected by the resonance shift in the 1D 15N spectra. In addition, RG7112 research buy a 2D homonuclear (13C–13C) MAS NMR experiment, using a phase-sensitive RFDR pulse sequence and a double CP/MAS experiment performed on U–15N and 13C labeled LH2, revealed that axial histidines in LH2 complex carry partial positive charge in an overall neutral Histidine/B850 complex (Alia et al. 2001) (Fig. 7). With DFT calculations these effects were analyzed in detail, and it was established that Fossariinae the histidines are subject to protein-induced strain that forces the histidine

imidazole side chain in the positive charge-type electronic configuration as a result of the NVP-BSK805 higher order self-assembly process (Wawrzyniak et al. 2008). Fig. 7 a 2-D homonuclear (13C–13C) and b heteronuclear (1H–13C) dipolar correlation spectrum of [13C6,15N3]-histidine labeled LH2 complex collected in a field of 17.6 T. The spectrum was recorded with a spinning frequency ω r/2π = 12 kHz at a temperature of 230 K. The 1H homonuclear interactions in b were suppressed with PMLG irradiation during proton evolution, applying a RF power corresponding with a nutation frequency of 74.4 kHz. Cross peaks from the cationic histidines (Type 2A) are indicated by (′) and cross peaks from the histidines bound with B850 (Type 2B) are indicated by (*) In addition to charge transfer, 2D heteronuclear (1H–13C) MAS experiments can assess the electronic delocalization and overlap in a chlorophyll ring. A 2D heteronuclear (1H–13C) MAS NMR experiment was performed using a 2D PMLG decoupled heteronuclear sequence (Alia et al. 2004).

Several new chemotherapy agents are being tested in combination w

Several new chemotherapy agents are being tested in combination with radiation, but the best chemotherapy remains to be determined. The fate of irradiated cells is believed to be controlled by the network of signaling elements that lead to different modes of cell death or survival. Many stress-responsive genes are inducible by IR [18, 19]. These radiation-inducible genes are believed to have effects on the chemosensitivity RXDX-101 manufacturer of tumor cells [13, 20]. To determine the correlation between radio-RG7420 chemical structure resistance and sensitivity to chemotherapeutic drugs in esophageal cancer cells, we then analyzed the chemosensitivity of

EC109 and EC109/R cells with chemotherapeutic drugs cisplatin, 5-fluorouracil, doxorubicin, paclitaxel or etoposide. EC109/R, which survived 80 Gy irradiation, became more sensitive to different concentrations of 5-fluorouracil, doxorubicin, paclitaxel and etoposide, but maintained tolerance to cisplatin, as assessed by MTT assay (Figure 4). These findings suggest that cellular resistance to ionizing radiation have effects on the chemotherapeutic drug sensitivity in esophageal cancer cells. Several genes associated with cellular sensitivity to anticancer drugs have been selected for esophageal cancer. They were B4GALT5 (UDP-Gal: βGlcNAc β1,4-galactosyltransferase, polypeptide 5 gene), UGCG (UDP-glucose ceramide

glucosyltransferase gene), and XBP1 (X-box binding protein 1 gene) for 5-fluorouracil, A-1210477 NRCAM (neuronal cell adhesion molecule gene) for doxorubicin, ARFRP1 (ADP-ribosylation factor related protein 1 gene), IFITM1 (interferon induced transmembrane protein 1 gene), KIAA0685, and SIPA1L2 (signalinduced proliferation-associated 1 like 2 gene) for cisplatin [14]. Fractionated irradiation might induce cellular sensitivity related gene and protein expression in human tumor cell lines. The fact

that drug Florfenicol sensitivity is determined by multiple genes required a better understanding of the intricate network of the selected genes in the expression levels. Fractionated radiation treatment has also been reported to cause drug resistance in ovarian carcinoma cells [21] and ascites tumor cells [22]. It can induce functionally relevant multidrug resistance gene and protein expression in human tumor cell lines [13]. There are multiple factors that contribute to cisplatin resistance, but alterations of DNA repair processes have been known for some time to be important in mediating resistance [23, 24]. The most important DNA repair pathways involved in the cisplatin response are nucleotide excision repair (NER) and mismatch repair (MMR). MSI, which results from disorder of the MMR system and loss of MLH1 protein, is frequently induced during cisplatin-based chemotherapy [25]. Data have shown that suppression of ERCC1 expression enhances or restores cisplatin sensitivity, and combination of p53 inactivation and MMR deficiency results in cisplatin resistance [26].

1999, 2002) Furthermore, state transitions in C reinhardtii are

1999, 2002). Furthermore, state transitions in C. reinhardtii are substantially affected by anaerobiosis. The PQ pool, whose reduction

state is one of the key signals for state transitions (see more Wollman 2001), is maximally reduced in the absence of O2, probably because PRIMA-1MET purchase the plastidic terminal oxidase as a part of the chlororespiratory pathway cannot function (Wollman and Delepelaire 1984). In addition, oxidation of exogenously provided acetate tends to cause reduction of the PQ-pool and can result in state transitions toward state 2 in the dark (Endo and Asada 1996). Having this in mind, one has to be careful not to let the algal sample become anoxic in the dark incubation prior to the measurement, unless this is desired. On the other hand, if one takes samples from the culture container to analyze S-deprived and H2-producing C. reinhardtii cells, this might result in some aeration

of the cells, causing a change in the bioenergetic status of the latter. Again, on-line measurements within a bioreactor are much better suited for the monitoring of the bioenergetic status of the photosynthetic apparatus and the cells themselves. Screening systems for the targeted isolation of mutants with an altered H2 metabolism this website Basic research on H2 metabolism and efforts to increase yields of H2 production by the microalgae make use of well-established techniques allowing forward Pregnenolone and reverse genetics in C. reinhardtii (Galván et al. 2007). To identify genes whose products are involved in the H2 metabolism of C. reinhardtii or to create strains with optimized phenotypes regarding H2 yields, transformant libraries are created by DNA insertional mutagenesis. This is an easy and well-established method to mutagenize C. reinhardtii and tag the affected genes simultaneously (Kindle 1990). However, to identify the strains of interest, a powerful screening system must be at hand. Here, research on both algal

hydrogenases and H2 metabolism has profited from the coupling of these processes with photosynthesis. Three screening systems with different objectives have been established, all of these relying on photosynthetic activity. The first screening protocol aims at identifying algal mutant strains with any defect affecting H2 production by making use of the fact that dark-adapted and anaerobic Chlamydomonas cells show a transient but high H2-production activity after a sudden dark–light shift. This screening utilizes the characteristics of tungsten oxide, which changes its color after being reduced by hydrogen. The second screening system has been established both for biotechnological reasons and optimizing the analysis of photosynthetic H2 production. It selectively screens for C.