Coral mortality and interaction with algae in relation to sedimentation

The impact of sedimentation on coral–algal interactions was studied by monitoring tissue mortality and radial growth in two coral species, Colpophyllia natans and Siderastrea siderea, over a continuum of sediment input intensities. This study sets out to investigate (1) whether sedimentation can facilitate algal overgrowth of corals and (2) whether this was a significant cause of coral mortality. Over a 15-month period, 198 coral colonies were tagged and photographed at six sites along two replicate gradients of sediment input, spanning high inputs near river mouths to low inputs at exposed headlands. Photographs were taken so that they covered the interface between colonies and algae. Radial growth was measured along colony edges in contact with algae and unaffected by tissue loss from causes other than competition with algae. To establish whether algal overgrowth was a significant cause of coral mortality, tissue mortality on the colony surface area visible in the photographs was related to different causes, including sediment smothering, disease, and algal overgrowth. Radial growth became negative with increasing proximity to river mouths in C. natans and remained negative or close to zero throughout the gradients in S. siderea, overall suggesting that sedimentation can facilitate algal overgrowth on corals. However, the analysis of tissue mortality revealed that algal overgrowth was a relatively minor cause of tissue loss. In contrast, the most important cause of coral mortality in relation to sedimentation was from sediment smothering, probably during intense episodes of deposition associated with heavy rainfall. We conclude that sedimentation may lead to reef degradation by causing coral mortality through sediment smothering and burial, and then by suppressing the regrowth of surviving adult colonies through increased competition with algae.     

Quantitative immunogold ultracryomicrotome stidies of the distribution of periimplantation proteins in the sheep

Summary Several mammalian uterine and conceptus proteins are produced at specific stages of implantation. Ovine trophoblast protein-1 (OTP-1) is only synthesised of pregnancy (dpc). This immunogold ultracryosection study shows that, during this period, OTP-1 immunoreactivity is only found in the Golgi body of the trophectodermal cells. A second protein, of 14 kD molecular weight (14K protein), has a more varied distribution being found in membrane-bounded crystals in uterine epithelium and trophectodermal cells, and distributed throughout the cytosol and nucleoplasm of the uterine epithelium. There are only trace amounts of the 14 K protein in the fetomaternal syncytium which replaces the uterine epithelium during implantation, and no crystals are found in the trophectoderm after cotyledonary villus formation is initiated at 24–25 dpc. The crystals containing 14 K protein persist throughout pregnancy in the intercotyledonary areas. The narrow time window of OTP-1 occurrence reinforces the suggestion that this represents an important developmental signal, whereas the distribution of the 14 K protein indicates a more general nutritive function.     

Defining regions of the Y-chromosome responsible for male infertility and identification of a fourth AZF region (AZFd) by Y-chromosome microdeletion detection

Cytogenetic and molecular deletion analyses of azoospermic and oligozoospermic males have suggested the existence of AZoospermia Factor(s) (AZF) residing in deletion intervals 5 and 6 of the human Y-chromosome and coinciding with three functional regions associated with spermatogenic failure. Nonpolymorphic microdeletions in AZF are associated with a broad spectrum of testicular phenotypes. Unfortunately, Sequence Tagged Sites (STSs) employed in screening protocols range broadly in number and mapsite and may be polymorphic. To thoroughly analyze the AZF region(s) and any correlations that may be drawn between genotype and phenotype, we describe the design of nine multiplex PCR reactions derived from analysis of 136 loci. Each multiplex contains 4-8 STS primer pairs, amplifying a total of 48 Y-linked STSs. Each multiplex consists of one positive control: either SMCX or MIC2. We screened four populations of males with these STSs. Population I consisted of 278 patients diagnosed as having significant male factor infertility: either azoospermia, severe oligozoospermia associated with hypogonadism and spermatogenic arrest or normal sperm counts associated with abnormal sperm morphology. Population II consisted of 200 unselected infertile patients. Population III consisted of 36 patients who had previously been shown to have aneuploidy, cytological deletions or translocations involving the Y-chromosome or normal karyotypes associated with severe phenotype abnormalities. Population IV consisted of 920 fertile (control) males. The deletion rates in populations I, II and III were 20.5%, 7% and 58.3%, respectively. A total of 92 patients with deletions were detected. The deletion rate in population IV was 0.87% involving 8 fertile individuals and 4 STSs which were avoided in multiplex panel construction. The ability of the nine multiplexes to detect pathology associated microdeletions is equal to or greater than screening protocols used in other studies. Furthermore, the data suggest a fourth AZF region between AZFb and AZFc, which we have termed AZFd. Patients with microdeletions restricted to AZFd may present with mild oligozoospermia or even normal sperm counts associated with abnormal sperm morphology. Though a definitive genotype/phenotype correlation does not exist, large deletions spanning multiple AZF regions or microdeletions restricted to AZFa usually result in patients with Sertoli Cell Only (SCO) or severe oligozoospermia, whereas microdeletions restricted to AZFb or AZFc can result in patients with phenotypes which range from SCO to moderate oligozoospermia. The panel of nine multiplexed reactions, the Y-deletion Detection System (YDDS), provides a fast, efficient and accurate method of assessing the integrity of the Y-chromosome. To date, this study provides the most extensive screening of a proven fertile male population in tandem with 514 infertile males, derived from three different patient selection protocols.     

The nesprins are giant actin-binding proteins,orthologous to Drosophila melanogaster muscle protein MSP-300

Nesprin-1 and nesprin-2 (also known as Syne-1 and Syne-2,) are large ( approximately 3300-residue) vertebrate proteins associated with emerin and lamin A at the nuclear envelope of muscle cells and other cell types. We show that the previously described nesprins are short isoforms of giant proteins comprising an actin-binding amino-terminus connected to a carboxy-terminal klarsicht-related transmembrane domain by a massive ( approximately 6000-8000 amino acid) spectrin-like rod domain, making full-length nesprin-1, at one megadalton, the largest non-titin protein hitherto described in humans. We find that MSP-300, a 7000-residue Drosophila melanogaster protein whose disruption results in defects of muscle development, corresponds to the N-terminal two-thirds of the Drosophila nesprin ortholog. A nesprin-like protein is also encoded by the nematode genome. Moreover, we demonstrate that the larger isoforms of nesprin-1, like MSP-300, are localized to the sarcomeric Z-line of both skeletal and cardiac muscle. The recognition that a characteristic muscle-specific mutant phenotype in the fly results from a disruption of its nesprin ortholog reinforces the candidacy of the human proteins for involvement in genetic diseases of skeletal and cardiac muscle.     

Production ofBeauveria bassiana [Deuteromycotina: Hyphomycetes] in different liquid media and subsequent conidiation of dry mycelium

Mycelium ofBeauveria bassiana can be grown in liquid culture, filtered, and the mycelium dried. After rehydration the mycelium sporulates. Two carbohydrate sources (sucrose and maltose), and one nitrogen/vitamin source (yeast extract) were tested for mycelium growth and subsequent conidial production. Maximum mycelium growth (12.31 mg/ml), in liquid culture, was in the sucrose (3.5%)/yeast extract (3.5%) medium, but mycelium from a maltose (2%)/yeast extract (0.75%) medium produced the maximum of 4.62×10⁶ conidia/mg dry mycelium after incubation in moist Petri dishes. Using the data on mycelium yield (in liquid culture) and conidial production (by dry mycelium) it is calculated that the sucrose (3.5%)/yeast extract (3.5%) and the maltose (2%)/yeast extract (0.75%) media produce most conidia per media volume (an equivalent of 3.52–3.72×10⁷ conidia/ml).      

Exploring gene-environment interactions in Parkinson’s disease

The objective of this study was to explore combined effects of four candidate susceptibility genes and two exposures on Parkinson’s disease (PD) risk; namely, α-synuclein (SNCA) promoter polymorphism REP1, microtubule-associated protein tau (MAPT) H1/H2 haplotypes, apolipoprotein E (APOE) ε2/ε3/ε4 polymorphism, ubiquitin carboxy-terminal esterase L1 (UCHL1) S18Y variant, cigarette smoking and caffeinated coffee consumption. 932 PD patients and 664 control subjects from the NeuroGenetics Research Consortium, with complete data on all six factors, were studied. Uniform protocols were used for diagnosis, recruitment, data collection and genotyping. A logistic regression model which included gene-exposure interactions was applied. Likelihood ratio tests (LRTs) were used for significance testing and Bayesian inference was used to estimate odds ratios (ORs). MAPT (P = 0.007), SNCA REP1 (P = 0.012), smoking (P = 0.001), and coffee (P = 0.011) were associated with PD risk. Two novel interactions were detected: APOE with coffee (P = 0.005), and REP1 with smoking (P = 0.021). While the individual main effects were modest, each yielding OR < 1.6, the effects were cumulative, with some combinations reaching OR = 12.6 (95% CI: 5.9–26.8). This study provides evidence for the long-held notion that PD risk is modulated by cumulative and interactive effects of genes and exposures. Furthermore, the study demonstrates that while interaction studies are useful for exploring risk relationships that might otherwise go undetected, results should be interpreted with caution because of the inherent loss of power due to multiple testing. The novel findings of this study that warrant replication are the evidence for interaction of coffee with APOE, and of smoking with REP1 on PD risk. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Electron paramagnetic and electron nuclear double resonance of the hydrogen peroxide compound of cytochrome c peroxidase

We have collected electron paramagnetic resonance (EPR) and electron nuclear double resonance (ENDOR) spectra from the hydrogen peroxide compound of yeast cytochrome c peroxidase, termed ES, employing EPR microwave frequencies of 9.6 and 11.6 GHz. We have measured and analyzed the temperature dependence of the spin-lattice relaxation rate (1/T1) of the paramagnetic center of ES over the temperature range 1.9 to 4 K. In addition, an upper bound to exchange coupling between the ferryl heme and EPR-visible centers of ES has been calculated and expressions for the dipolar interaction between a ferryl heme and a free radical have been derived. These results all confirm that the EPR signal of ES is not associated with an aromatic amino acid radical, and in particular not with a tryptophanyl radical. This conclusion has led us to consider an explanation of the EPR signal in terms of a nucleophilically stabilized methionyl radical.     

Supplementation with vitamin E but not with vitamin C lowers lipid peroxidation in vivo in mildly hypercholesterolemic men.

Although the use of vitamin E supplements has been associated with a reduction in coronary events, assumed to be due to lowered lipid peroxidation, there are no previous long-term clinical trials into the effects of vitamin C or E supplementation on lipid peroxidation in vivo. Here, we have studied the long-term effects of vitamins C and E on plasma F2-isoprostanes, a widely used marker of lipid peroxidation in vivo. As a study cohort, a subset of the "Antioxidant Supplementation in Atherosclerosis Prevention" (ASAP) study was used. ASAP is a double-masked placebo-controlled randomized clinical trial to study the long-term effect of vitamin C (500 mg of slow release ascorbate daily), vitamin E (200 mg of D-alpha-tocopheryl acetate daily), both vitamins (CellaVie), or placebo on lipid peroxidation, atherosclerotic progression, blood pressure and myocardial infarction (n = 520 at baseline). Lipid peroxidation measurements were carried out in 100 consecutive men at entry and repeated at 12 months. The plasma F2-isoprostane concentration was lowered by 17.3% (95% CI 3.9-30.8%) in the vitamin E group (p = 0.006 for the change, as compared with the placebo group). On the contrary, vitamin C had no significant effect on plasma F2-isoprostanes as compared with the placebo group. There was also no interaction in the effect between these vitamins. In conclusion, long-term oral supplementation of clinically healthy, but hypercholesterolemic men, who have normal vitamin C and E levels with a reasonable dose of vitamin E lowers lipid peroxidation in vivo, but a relatively high dose of vitamin C does not. This observation may provide a mechanism for the observed ability of vitamin E supplements to prevent atherosclerosis.