Parkinson's disease: a case-control study of occupational and environmental risk factors

We compared personal histories of 57 cases and 122 age-matched controls to identify possible environmental determinants of Parkinson's disease (PD). Odds ratios (OR) adjusted for sex, age, and smoking were computed using stepwise logistic regression. We found a statistically significant increased risk for working in orchards (OR = 3.69, p = 0.012, 95% CI = 1.34, 10.27) and a marginally significant increased risk associated with working in planer mills (OR = 4.11, p = 0.065, 95% CI = 0.91, 18.50). A Fisher's exact test of the association between PD development and (1) paraquat contact, and (2) postural tremor gave statistically significant probability estimates of 0.01 and 0.03, respectively. The relative risk of PD decreased with smoking, an inverse relationship supported by many studies.

Child development and long-term outcomes: a population health perspective and summary of successful interventions

Studies of socioeconomic gradients in mortality in wealthy societies reveal that they have been persist, and included most of the principal causes of death, even during the era when these principal causes of death have entirely changed. This observation has led to an interest in the ways in which the diversity of conditions of life, unfolding over the life cycle, can become embedded in human biology and subsequently affect health status and vitality. There is evidence that childhood experiences affect subsequent health status (as well as well-being and competence) in profound and long-lasting ways. Conflicting explanatory models of the impact of childhood experiences have been advanced, whose conflicts are political in nature, in that the reflect divergent beliefs about how human potential expresses itself, and, also, about the nature of the obligations which members of society have to one another. Notwithstanding these conflicts, a body of evidence derived from intervention studies in the post-neonatal, preschool, and school age periods suggest that performance in two basic domains of child development, the cognitive and the social-emotional, can be modified in ways which improve health, well-being, and competence in the long-term.

Effects of antihypertensive drug treatments on fracture outcomes: a meta-analysis of observational studies

OBJECTIVE

To quantitatively pool findings from observational studies on the risk of fracture outcomes associated with exposure to five antihypertensive drug classes: angiotensin-converting enzyme (ACE) inhibitors, diuretics (in particular thiazide diuretics), beta-blockers, calcium-channel blockers and alpha-blockers.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Publications listed in the MEDLINE, EMBASE and LILACS databases, the ISI proceedings, and bibliographies of retrieved articles. Sources were searched from the earliest possible dates through December 2005.

REVIEW METHODS

We included case-control and cohort studies presenting relative risks and confidence intervals (CIs) for the association between exposure to antihypertensive agents and fracture outcomes. Data were extracted onto a standardized computer worksheet. Study quality was assessed using a 10-point questionnaire specific to case-control or cohort study design.

RESULTS

Fifty-four studies were identified. Pooled estimates were computed using the software HEpiMA. The pooled relative risk (RR) of any fracture with use of thiazide diuretics was 0.86 (95% CI 0.81-0.92) and 1.14 (95% CI 0.84-1.54) with use of nonthiazide diuretics. There was a statistically significant reduction of any fracture with use of beta-blockers, (RR 0.86, 95% CI 0.70-0.98). The one study with ACE inhibitor data showed protection (RR 0.81, 95% CI 0.73-0.89). No significant associations were found between fractures and exposure to alpha-blockers or calcium-channel blockers.

CONCLUSIONS

Thiazide diuretics and beta-blockers appear to lower the risk of fractures in older adults. However, these agents cannot be recommended as preventive therapies for fractures until data from randomized controlled trials have established their efficacy. Patients who use these inexpensive drugs as treatments for hypertension may also benefit from a reduction in fracture risk.

A case-control study of Parkinson's disease in a horticultural region of British Columbia

We compared personal histories of 127 cases and 245 controls to identify possible environmental risk factors for idiopathic parkinsonism (IP). Of our controls, 121 had cardiac disease (CD) and 124 were randomly selected from electoral lists (voters). Using logistic regression and adjusting for sex and age, we ran separate analyses: IP versus CD and IP versus voters. A full occupational history was collected, as was known contact with all pesticides associated with the tree fruit sector of the agricultural industry. We found a significant association between IP and having had an occupation in which exposure through handling or directly contacting pesticides was probable, but no specific chemicals were associated with IP. We conclude that although occupations involving the use of agricultural chemicals may predispose to the development of IP, it seems likely that the pathogenesis is multifactorial rather than related to a specific agent.

Comparison of quadruple immunosuppression after liver transplantation with ATG or IL-2 receptor antibody

Treatment with monoclonal IL-2 receptor antibodies has been successfully used for immunosuppressive induction therapy following organ transplantation in the recent past. The present study was conducted to compare for the first time a cyclosporine-based quadruple immunosuppressive regimen including a monoclonal IL-2 receptor antibody or ATG as induction therapy after orthotopic liver transplantation. In two groups of 33 patients each, postoperative survival, graft biopsies, liver function enzymes, and the clinical courses after OLT were evaluated. Our results indicate that monoclonal IL-2 receptor antibody therapy as part of a quadruple immunosuppressive regimen is better tolerated and is at least as effective as ATG in prevention of allograft rejection following OLT. Furthermore, our data indicate that a slightly better liver function in general and a lower incidence of rejection reactions necessitating treatment could be observed in the group of patients treated with the monoclonal IL-2 receptor antibody. This study provides evidence that monoclonal IL-2 receptor antibody therapy may be a useful tool for the immunosuppressive induction therapy following clinical orthotopic liver transplantation.

Silicate modulates the cross-talk between osteoblasts (SaOS-2) and osteoclasts (RAW 264.7 cells): inhibition of osteoclast growth and differentiation

It has been shown that inorganic monomeric and polymeric silica/silicate, in the presence of the biomineralization cocktail, increases the expression of osteoprotegerin (OPG) in osteogenic SaOS-2 sarcoma cells in vitro. In contrast, silicate does not affect the steady-state gene expression level of the osteoclastogenic ligand receptor activator of NF-κB ligand (RANKL). In turn it can be expected that the concentration ratio of the mediators OPG/RANKL increases in the presence of silicate. In addition, silicate enhances the growth potential of SaOS-2 cells in vitro, while it causes no effect on RAW 264.7 cells within a concentration range of 10-100 µM. Applying a co-cultivation assay system, using SaOS-2 cells and RAW 264.7 cells, it is shown that in the presence of 10 µM silicate the number of RAW 264.7 cells in general, and the number of TRAP(+) RAW 264.7 cells in particular markedly decreases. The SaOS-2 cells retain their capacity of differential gene expression of OPG and RANKL in favor of OPG after exposure to silicate. It is concluded that after exposure of the cells to silicate a factor(s) is released from SaOS-2 cells that causes a significant inhibition of osteoclastogenesis of RAW 264.7 cells. It is assumed that it is an increased secretion of the cytokine OPG that is primarily involved in the reduction of the osteoclastogenesis of the RAW 264.7 cells. It is proposed that silicate might have the potential to stimulate osteogenesis in vivo and perhaps to ameliorate osteoporotic disorders.

Molecular evolution of apoptotic pathways: cloning of key domains from sponges (Bcl-2 homology domains and death domains) and their phylogenetic relationships

Cells from metazoan organisms are eliminated in a variety of physiological and pathophysiological processes by apoptosis. In this report, we describe the cloning and characterization of molecules from the marine sponges Geodia cydonium and Suberites domuncula, whose domains show a high similarity to those that are found in molecules of the vertebrate Bcl-2 superfamily and of the death receptors. The Bcl-2 proteins contain up to four Bcl-2 homology regions (BH). Two Bcl-2-related molecules have been identified from sponges that are provided with two of those regions, BH1 and BH2, and are termed Bcl-2 homology proteins (BHP). The G. cydonium molecule, BHP1_GC, has a putative size of 28,164, while the related sequence from S. domuncula, BHP1_SD, has a M(r) of 24,187. Phylogenetic analyses of the entire two sponge BHPs revealed a high similarity to members of the mammalian Bcl-2 superfamilies and to the Caenorhabditis elegans Ced-9. When the two domains, BH1 and BH2, are analyzed separately, again the highest similarity was found to the members of the Bcl-2 superfamily, but a clearly lower relationship to the C. elegans BH1 and BH2 domains in Ced-9. In unrooted phylogenetic trees the sponge BH1 and BH2 are grouped among the mammalian sequences and are only distantly related to the C. elegans BH domains. The analysis of the gene structure of the G. cydonium BHP showed that the single intron present is located within the BH2 domain at the same position as in C. elegans and rat Bcl-x(L). In addition, a sponge molecule comprising two death domains has been characterized from G. cydonium. The two death domains of the potential proapoptotic molecule GC_DD2, M(r) 24,970, share a high similarity with the Fas-FADD/MORT1 domains. A death domain-containing molecule has not been identified in the C. elegans genome. The phylogenetic analysis revealed that the sponge domain originated from an ankyrin building block from which the mammalian Fas-FADD/MORT1 evolved. It is suggested that the apoptotic pathways that involve members of the Bcl-2 superfamily and of the death receptors are already present in the lowest metazoan phylum, the Porifera.

Reciprocal inhibition following lesions of the spinal cord in man

1. Reciprocal inhibition was studied in normal subjects and patients with spinal cord lesions by stimulating the posterior tibial nerve below the threshold of the soleus alpha-motoneurone axons and recording the changes in firing probability of single tibialis anterior motor units activated by voluntary contraction. A short-latency (about 35 ms) period of decreased firing probability was assumed to represent reciprocal inhibition. 2. For a given stimulus intensity this inhibition was greater in patients with spinal lesions than in normal subjects. 3. The stimulus intensities at which soleus motoneurones and the Ia inhibitory interneurones were brought to threshold provided an estimate of the relative excitability of these two neural populations. In the patients with spinal lesions the Ia inhibitory interneurones were more excitable than soleus motoneurones, whereas in normal subjects the excitabilities were approximately equal. 4. Stimulation of the posterior tibial nerve below the threshold of alpha-motoneurone axons also resulted in a second period of inhibition with a latency of approximately 50 ms. This was less prominent in the patients with spinal cord lesions. 5. It is concluded that transmission through the pathways mediating reciprocal inhibition of flexor muscles during their voluntary contraction is enhanced following a spinal cord lesion in man but that a later inhibitory process is depressed.

Origin of the interferon-inducible (2'-5')oligoadenylate synthetases: cloning of the (2'-5')oligoadenylate synthetase from the marine sponge Geodia cydonium

In vertebrates cytokines mediate innate (natural) immunity and protect them against viral infections. The cytokine interferon causes the induction of the (2'-5')oligoadenylate synthetase [(2-5)A synthetase], whose product, (2'-5')oligoadenylate, activates the endoribonuclease L which in turn degrades (viral) RNA. Three isoforms of (2-5)A synthetases exist, form I (40-46 kDa), form II (69 kDa), and form III (100 kDa). Until now (2-5)A synthetases have only been cloned from birds and mammals. Here we describe the cloning of the first putative invertebrate (2-5)A synthetase from the marine sponge Geodia cydonium. The deduced amino acid sequence shows signatures characteristic for (2-5)A synthetases of form I. Phylogenetic analysis of the putative sponge (2-5)A synthetase indicates that it diverged first from a common ancestor of the hitherto known members of (vertebrate) (2-5)A synthetases I, (2-5)A synthetases II and III. Moreover, it is suggested that the (2-5)A synthetases II and III evolved from this common ancestor (very likely) by gene duplication. Together with earlier results on the existence of the (2'-5')oligoadenylates in G. cydonium, the data presented here demonstrate that also invertebrates, here sponges, are provided with the (2-5)A system. At present, it is assumed that this system might be involved in growth control, including control of apoptosis, and acquired its additional function in innate immune response in evolutionarily younger animals, in vertebrates.

Luciferase a light source for the silica-based optical waveguides (spicules) in the demosponge Suberites domuncula

Two classes of sponges (animal phylum Porifera) possess a siliceous skeleton which is composed of spicules. Studying the optical fiber-mechanical properties of large spicules from hexactinellid sponges (> 5 cm) it was demonstrated that they are effective light-collecting optical fibers. Here, we report that the demosponge Suberites domuncula is provided with a biosensor system composed of the (organic) light producing luciferase and the (inorganic) light transducing silica spicules. The light transmission feature of these smaller spicules (200 microm) has been demonstrated and the ability of sponge tissue to generate light has been proven. Screening for a luciferase gene in S. domuncula was successful; the recombinant luciferase was prepared and shown to be bioactive. The luciferase protein is abundantly present in the close neighborhood of the spicules. The expression of the luciferase gene is under the control of light.

Sponge Bcl-2 homologous protein (BHP2-GC) confers distinct stress resistance to human HEK-293 cells

It is established that sponges, the phylogenetically oldest still extant phylum of Metazoa, possess key molecules of the apoptotic pathways, that is members from the Bcl-2 family and a pro-apoptotic molecule with death domains. Here we report on transfection studies of human cells with a sponge gene, GCBHP2. Sponge tissue was exposed to heat shock and tributyltin, which caused an upregulation of gene expression of GCBHP2. The cDNA GCBHP2 was introduced into human HEK-293 cells and mouse NIH-3T3 cells; the stable transfection was confirmed by the identification of the transcripts, by Western blotting as well as by immunofluorescence using antibodies raised against the recombinant polypeptide. HEK-293 cells, transfected with GCBHP2, showed high resistance to serum starvation and tributyltin treatment, compared to mock-transfected cells. In contrast to mock-transfected cells, GCBHP2-transfected cells activated caspase-3 to a lower extent. Thus, sponges contain gene(s) involved in apoptotic pathway(s) displaying their function also in human cells.

Repeated measurements of pulmonary function following spinal cord injury

Twelve subjects (11 males, 1 female) with complete spinal cord lesion (level of lesion ranging from C4 to T10), with a mean age of 23.5 years participated in pulmonary function testing (PFT). Inspiratory and expiratory flow measurements were made at 2-month intervals from 25 to 351 days post injury. The values were interpolated and extrapolated to common dates to facilitate comparison. The effect of time on pulmonary function was determined by a repeated measures ANOVA. Forced expiratory volume in 1 second (FEV1.0) significantly increased during the course of the study (40%, p < 0.05), but increases in forced vital capacity (FVC) (32.5%) and maximal voluntary ventilation (MVV) (16%) were not statistically significant. Lesion level was found to be correlated (Spearman Product Moment Correlation) with pulmonary function if a single measure was made (r = 0.55 to 0.73), but emerged as a stronger predictor if the average of several repeated PFTs was correlated with lesion level (r = 0.74 to 0.84). In addition, lesion level was not correlated with the amount of improvement attained during the time period studied. We conclude that the time course of recovery of pulmonary function is variable between individuals with spinal cord injuries and can only be weakly predicted by knowledge of the initial value and the lesion level.

Increased expression of the potential proapoptotic molecule DD2 and increased synthesis of leukotriene B4 during allograft rejection in a marine sponge

Sponges (Porifera) are a classical model to study the events during tissue transplantation. Applying the 'insertion technique' autografts from the marine sponge Geodia cydonium fuse within 5 days. In contrast, allografts are rejected and destroyed. Here we show that during allograft rejection the cells in the grafts undergo apoptosis; 5 days after transplantation 46% of the cells show signs of apoptosis. In a previous study it was shown that during this process a tumor necrosis factor-like molecule is induced in allo- and xenografts. Molecules grouped to the superfamily of tumor necrosis factor receptors and a series of associated adapter molecules contain the characteristic death domain. Therefore, we screened for a cDNA encoding such a domain. Here we report on the first invertebrate molecule from Geodia cydonium comprising a death domain. The potential proapoptotic molecule DD2, with a calculated Mr of 24 970, possesses in contrast to all known mammalian death domain-containing proteins two such domains with highest similarity to the death domain present in human Fas/APO-1. The expression of this gene is not detectable in control tissue but strongly upregulated in allografts; only very low expression is seen in autografts. Parallel with the increase of the expression of the potential proapoptotic molecule DD2 in allografts the level of LTB4 drastically increases from 2.5 pg/mg of protein (controls) to 389 pg LTB4/mg during a period of 5 days after transplantation; the level of LTB4 in autografts does not change. Very likely in response to inflammatory reactions the LTB4 metabolizing enzyme LTB4 12-hydroxy-dehydrogenase is expressed both in auto- and allografts. These results demonstrate that sponges are provided with apoptotic pathways, similar to those present in deuterostomes and apparently absent in protostomes, which are composed of molecules comprising a death domain. In addition, it is suggested that in sponges LTB4 is one metabolite which is involved in the initiation of apoptosis. It is postulated that the potential proapoptotic effect of LTB4 is prevented in auto-grafts by the expression of the LTB4 12-hydroxy-dehydrogenase.

Cell death in Porifera: molecular players in the game of apoptotic cell death in living fossils

Apoptosis represents the morphological manifestation of programmed cell death and, paradoxically at first sight, it is a prerequisite for metazoan life. Thus, apoptosis is responsible for the demise of cells during many physiological processes. It is also accountable for the death of cells following exposure to countless stimuli. Therefore, it is obvious that apoptosis must be regulated by a complex network of various molecular signaling pathways. Research during the past 20 years has led to the identification of major functional groups of molecules involved in apoptotic pathways. These include members of the Bcl-2 superfamily, members of the TNF family, caspases, and their activators. Yet, the evolutionary conservation of those elements of the apoptotic machinery was only established from nematode to man. Sponges (phylum Porifera) are characterized by a remarkable regeneration capacity and longevity. Furthermore, they represent the phylogenetically oldest still extant metazoan taxon. Thus, research on these living fossils opens a window to the past, to the dawn of metazoan life. It allows us to trace the evolution of programmed cell death and its core components. This review summarizes the key findings and concepts which have emerged from studies of apoptosis in Porifera.

Induction of heat-shock (stress) protein gene expression by selected natural and anthropogenic disturbances in the octocoral Dendronephthya klunzingeri

Previously it was found that the expression of selected heat-shock proteins is upregulated in corals after exposure to elevated temperature. We published that HSPs are suitable markers in sponges to monitor the degree of environmental stress on these animals. In the present study the heat-shock proteins (HSPs) with a molecular weight of 90 kDa have been selected to prove their potential usefulness as biomarkers under controlled laboratory conditions and in the field. The studies have been performed with the octocoral Dendronephthya klunzingeri4.5-fold higher steady-state level of the respective mRNA. Also animals taken from stressed locations in the field showed an increased expression. The amount of HSP90 protein in D. klunzingeri was found to be strongly increased under thermal stress, or exposure to polychlorinated biphenyl (congener 118), but not after treatment with cadmium. Field studies revealed that samples taken from a nonstressed area have a low level of HSP90, but those collected from locations at which the corals are under physical stress (sedimentation through landfilling) show a high expression of HSP90. It is concluded that the chaperone HSP90 might become a suitable biomarker to monitor environmental stress on corals.

Towards an understanding of the molecular basis of immune responses in sponges: the marine demosponge Geodia cydonium as a model

The phylogenetic position of the phylum Porifera (sponges) is near the base of the kingdom Metazoa. During the last few years, not only rRNA sequences but, more importantly, cDNA/genes that code for proteins have been isolated and characterized from sponges, in particular from the marine demosponge Geodia cydonium. The analysis of the deduced amino acid sequences of these proteins allowed a molecular biological approach to the question of the monophyly of the Metazoa. Molecules of the extracellular matrix/basal lamina, with the integrin receptor, fibronectin, and galectin as prominent examples, and of cell-surface receptors (tyrosine kinase receptor), elements of sensory systems (crystallin, metabotropic glutamate receptor) as well as homologs/modules of an immune system (immunoglobulin-like molecules, scavenger receptor cysteine-rich [SRCR]- and short consensus repeats [SCR]-repeats), classify the Porifera as true Metazoa. As living fossils, provided with simple, primordial molecules allowing cell-cell and cell-matrix adhesion as well as processes of signal transduction as known in a more complex manner from higher Metazoa, sponges also show pecularities not known in later phyla. In this paper, the adhesion molecules presumably involved in the sponge immune system are reviewed; these are the basic adhesion molecules (galectin, integrin, fibronectin, and collagen) and especially the highly polymorphic adhesion molecules, the receptor tyrosine kinase as well as the polypeptides comprising scavenger receptor cysteine-rich (SRCR) and short consensus repeats (SCR) modules. In addition, it is reported that in the model sponge system of G. cydonium, allogeneic rejection involves an upregulation of phenylalanine hydroxylase, an enzyme initiating the pathway to melanin synthesis.

Inhibitory effects of extracts from the marine alga Caulerpa taxifolia and of toxin from Caulerpa racemosa on multixenobiotic resistance in the marine sponge Geodia cydonium

The invasive growth of the introduced green alga Caulerpa taxifolia, already affecting the richness and diversity of the littoral ecosystems, has become a major ecological problem in the Mediterranean Sea. Previously, we demonstrated that the water pollutant tributyltin induces apoptosis in tissue of the marine sponge Geodia cydonium at concentrations of 3 μM and higher. Here we show that exposure of G. cydonium to low (non-toxic) concentrations of Caulerpa extract or purified caulerpin (10 μg/ml) together with low doses of tributyltin (1 μM; non-toxic), results in a strong apoptotic effect. Evidence is presented that the enhancement of toxicity of tributyltin by Caulerpa extract is at least partially caused by inhibition of the multixenobiotic resistance (MXR) pump by the algal toxin. Caulerpa extract, as well as caulerpin, strongly enhance the accumulation of the test substrate of MXR, rhodamine B, in the gills of the mussel Dreissena polymorpha, used as a model system for testing MXR-inhibiting potential.

Demonstration of cytomegalovirus by polymerase chain reaction after liver transplantation

The polymerase chain reaction (PCR) is a highly sensitive and specific technique for detection of cytomegalovirus DNA. With this method we prospectively analyzed buffy coat leukocytes at weekly intervals over 3 months in 60 patients after liver transplantation (LTX). The PCR results were correlated with the pretransplant donor/recipient CMV antibody status and with the occurrence of CMV-induced disease. Thirty-three of 60 (55%) patients became PCR-positive during their posttransplant course. None of the 27 patients with permanent negative PCRs developed CMV disease. Of 33 patients with positive PCRs, 13 (39%) became ill. CMV disease developed in 9 of 22 (41%) antibody-negative recipients but only in 4 of 38 (10%) seropositive graft recipients. The incidence of CMV disease was 75% (9 of 12 patients) in seronegative recipients who converted to positive PCR results and 19% (4 of 21 patients) in seropositive patients with positive PCR findings. The predictive value of a positive PCR was 75% in seronegative patients but it was low (19%) in seropositive recipients. The predictive value of a negative PCR is 100%. Thus, PCR determinations are useful in identifying patients who will not develop CMV disease and in narrowing down the number of individuals who will become sick. Further, PCR is a helpful tool in the follow-up of patients under antiviral treatment.

The Chemokine Networks in Sponges: Potential Roles in Morphogenesis, Immunity and Stem Cell Formation

Porifera (sponges) are now well accepted as the phylum which branched off first from the common ancestor of all metazoans, the Urmetazoa. The transition to the Metazoa became possible because during this phase, cell-cell as well as cell-matrix adhesion molecules evolved which allowed the formation of a colonial stage of animals. The next prerequisite for the evolution to the Urmetazoa was the establishment of an effective immune system which, flanked by apoptosis, allowed the formation of a first level of individuation. In sponges (with the model Suberites domuncula and Geodia cydonium), the main mediators of the immune responses are the chemokines. Since sponges lack a vascular system and consequently blood cells (in the narrow sense), we have used the term chemokines (in a broad sense) to highlight that the complex network of intercellular mediators initiates besides differentiation processes also cell movement. In the present review, the cDNAs encoding the following chemokines were described and the roles of their deduced proteins during self-self and nonself recognition outlined: the allograft inflammatory factor, the glutathione peroxidase, the endothelial-monocyte-activating polypeptide, the pre-B-cell colony-enhancing factor and the myotrophin as well as an enzyme, the (2-5)A synthetase, which is involved in cytokine response in vertebrates. A further step required to reach the evolutionary step of the integrated stage of the Urmetazoa was the acquisition of a stem cell system. In this review, first markers for stem cells (mesenchymal stem cell-like protein) as well as for chemokines involved in the maintenance of stem cells (noggin and glia maturation factor) are described at the molecular level, and a first functional analysis is approached. Taken together, it is outlined that the chemokine network was essential for the establishment of metazoans, which evolved approximately 600 to 800 million years ago.

Phenylalanine hydroxylase from the sponge Geodia cydonium: implication for allorecognition and evolution of aromatic amino acid hydroxylases

The prophenoloxidase activating system is a defense system, frequently reported both in protostomes and in deuterostomes. The final product of the phenoloxidase activity is melanin which is ubiquitously present throughout the metazoan kingdom. The melanin synthesis pathway starts with the amino acid [aa] phenylalanine which is converted to tyrosine by the phenylalanine hydroxylase [PAH]. We show that after allo-transplantation in the marine sponge Geodia cydonium PAH is upregulated in the grafts. Enzyme determination studies revealed that PAH activity increases by three-fold two d after transplantation and reaches its maximum after 3d (by 3.7-fold). This finding was supported by determining the steady-state level of the mRNA for PAH. Furthermore the cDNA, encoding this enzyme was isolated from G. cydonium. Its deduced aa sequence encodes a protein of 51 kDa. Alignment studies indicate that the sponge PAH shares the consensus pattern as well as one characteristic pterin-binding site with the biopterin-dependent aromatic amino acid hydroxylases. Phylogenetic analysis of sponge PAH shows that all metazoan PAH fall in one group with the sponge PAH as the oldest member. The related classes of enzymes, the tyrosine hydroxylases and the tryptophan hydroxylases are statistically significantly separated from PAH; the tyrosine hydroxylase diverged as the first class from the common ancestor, a process which was calculated to have occurred 500 million years ago. It is concluded that in the sponge model system G. cydonium allogeneic rejection involves an upregulation of PAH, an enzyme initiating the pathway to melanin synthesis.

Enhancing fluorescent protein photostability through robot-assisted photobleaching

Improving fluorescent proteins through the use of directed evolution requires robust techniques for screening large libraries of genetic variants. Here we describe an effective and relatively low-cost system for screening libraries of fluorescent protein variants for improved photostability in the context of colonies on a Petri dish. Application of this system to the yellow fluorescent protein mCitrine, led to the development of Citrine2 with improved photostability and similar high fluorescent brightness. The photobleaching robot was constructed using a Lego Mindstorms Ev3 set and a xenon arc lamp, which together create even and high irradiance over an entire Petri dish through patterned illumination.

A homolog of the putative tumor suppressor QM in the sponge Suberites domuncula: downregulation during the transition from immortal to mortal (apoptotic) cells

The activation of components of the transcription factors such as AP-1 or c-jun is essential for a physiological response of metazoan cells during aging. The activity of such proto-oncoproteins is under enzymatic control. The function of c-jun is additionally modulated by the QM protein. Here, we studied the expression of the gene, encoding the QM-like protein in the sponge Suberites domuncula. These animals contain high levels of telomerase in their somatic cells. To understand the switch from telomerase-positive immortal cells to telomerase-negative mortal cells which undergo apoptosis, the expression of the QM-like gene was measured in this system. The cDNA, termed QMSD, encoding the QM-like protein was isolated from S. domuncula; its 642 bp long open reading frame encodes a putative protein, QM-SUBDO, of 24,702 Da. Phylogenetic analysis of the sponge QM-like protein revealed that it is closely related to other metazoan QM polypeptides and distinct from sequences of Eumycota or Viridiplantae. Our investigations demonstrated that in gemmules as well as in untreated tissue the expression of the QM-like gene is significantly higher than in tissue which undergoes induced apoptosis. The level of the QM-like protein even decreases drastically in cells that are induced to apoptosis (e.g. by cadmium). We suggest therefore that one event that is involved in the transition of sponge cells from their immortal telomerase-positive to the mortal telomerase-negative state may be the downregulation of the QM-like protein, a putative tumor suppressor polypeptide.

A photochromic and thermochromic fluorescent protein

An engineered fluorescent protein exhibits visibly striking photochromism and thermochromism under ambient conditions.

Bioinspired self-assembly of tyrosinase-modified silicatein and fluorescent core-shell silica spheres

Inspired by the intermolecular cross-linking of mussel foot proteins and their adhesive properties, tyrosinase has been used to modify recombinant silicatein. DOPA/DOPAquinone-mediated cross-linking and interfacial interactions enhanced both self-assembly of silicatein building blocks and templating of core-shell silica spheres, resulting in fluorescent biomimetic silicatein-silica hybrid mesofibers.