A meta-analysis of seaweed impacts on seagrasses: generalities and knowledge gaps

Seagrasses are important habitat-formers and ecosystem engineers that are under threat from bloom-forming seaweeds. These seaweeds have been suggested to outcompete the seagrasses, particularly when facilitated by eutrophication, causing regime shifts where green meadows and clear waters are replaced with unstable sediments, turbid waters, hypoxia, and poor habitat conditions for fishes and invertebrates. Understanding the situations under which seaweeds impact seagrasses on local patch scales can help proactive management and prevent losses at greater scales. Here, we provide a quantitative review of available published manipulative experiments (all conducted at the patch-scale), to test which attributes of seaweeds and seagrasses (e.g., their abundances, sizes, morphology, taxonomy, attachment type, or origin) influence impacts. Weighted and unweighted meta-analyses (Hedges d metric) of 59 experiments showed generally high variability in attribute-impact relationships. Our main significant findings were that (a) abundant seaweeds had stronger negative impacts on seagrasses than sparse seaweeds, (b) unattached and epiphytic seaweeds had stronger impacts than 'rooted' seaweeds, and (c) small seagrass species were more susceptible than larger species. Findings (a) and (c) were rather intuitive. It was more surprising that 'rooted' seaweeds had comparatively small impacts, particularly given that this category included the infamous invasive Caulerpa species. This result may reflect that seaweed biomass and/or shading and metabolic by-products like anoxia and sulphides could be lower for rooted seaweeds. In conclusion, our results represent simple and robust first-order generalities about seaweed impacts on seagrasses. This review also documented a limited number of primary studies. We therefore identified major knowledge gaps that need to be addressed before general predictive models on seaweed-seagrass interactions can be build, in order to effectively protect seagrass habitats from detrimental competition from seaweeds.     

三羟异黄酮对HER-2/neu高表达乳腺癌细胞血管生成相关因子表达的影响

三羟异黄酮(genistein)是大豆中的一种非营养成分,其结构与黄酮化合物类似,能竞争性地与雌激素受体结合,故称之为植物雌激素(phytoestrogen)。它具有广泛的生物学作用,如抗肿瘤、抗病毒、抗真菌、抗氧化、抗突变、抗高血压、抗增生等,其中genistein抑制肿瘤的血管生成是当前研究的热点之一。肿瘤的血管生成是肿瘤进一步生长转移的基础,该过程受肿瘤细胞和血管内皮细胞分泌的血管生成相关因     

Expression of Lewis antigenic determinants in colorectal adenocarcinomas

Expression of type 1 and type 2 chain Lewis antigens was studied in 32 rectal adenocarcinoma specimens; the results were correlated with the patients' Lewis phenotype and secretor status. In addition, the pattern of expression of these antigens was analyzed in adjacent and distant normal mucosa. We used an indirect immunofluorescence technique with p-phenylenediamine counterstaining (Oriol technique) and a panel of monoclonal antibodies directed against the different antigenic specificities. Normal distal colonic mucosa only expresses monofucosylated structures (Lea and X) arising from activity of the alpha 1-3,4-fucosyltransferase coded by the Le gene. Rectal adenocarcinomas also show Lea and X, but also reexpress blood group antigens ABH and exhibit difucosylated determinants (Leb and Y). The accumulation of mono- and difucosylated type 2 chain in neoplastic processes, independently of the Le and Se genes, could be due to the enzymes coded by reactivation of the H and X genes. Blood group antigens form a complex signal code, genetically regulated, which intervenes in differentiation, growth and cellular recognition processes, and which may undergo important modifications during malignant transformation. These alterations could be useful in the diagnosis and prognosis of some types of carcinoma.     

An Imported Case of Blastomyces Dermatitidis Infection in Mexico

Blastomycosis is an acute or chronic primary infection of the respiratory system, endemic in North America (United States of America and Canada), Africa and Asia. We report a case in Mexico, in a three years old child who had been born in California and lived in Chicago, U.S.A. The patient presented pulmonary symptoms prior to development of a skin ulcer. Blastomyces dermatitidis was identified by mycological and molecular procedures. The patient was successfully treated with amphotericin B, oral ketoconazole and itraconazole.     

The occurrence of the freshwater isopod Heterias (Fritzianira) exul in the Lakes Region of Chile,with notes on the genus Heterias (Asellota: Janiridae)

Heterais exul, previously known from Brazil and Argentina, was collected from a number of lakes and streams in the Lakes Region of Chile (between Valdivia and Puerto Montt). It was found in a wide variety of habitats: on leaf litter, detritus, algae, rotting wood, emergent vegetation, and clean sandy bottoms. Heterias, Pseudasellus, and Fritzianira are placed in synonymy, but Fritzianira is maintained as a subgenus of Heterias because of its lack of an antenna) scale. The 3 Australian species of Heterias and H. exul are believed to have evolved from a common freshwater Gondwanaland ancestor.     

Induced fit of an epitope peptide to a monoclonal antibody probed with a novel parallel surface plasmon resonance assay

Class II major histocompatibility complex proteins bind peptides for presentation to T-cells as part of the immune response process. Monoclonal antibody MEM-265 recognizes the peptide-free conformation of the major histocompatibility complex class II protein HLA-DR1 through specific binding to an epitope contained between residues 50-67 of the beta-chain. In previous work using alanine scanning (1), we identified residues Leu-53, Asp-57, Tyr-60, Trp-61, Ser-63, and Leu-67 as essential for specific recognition by MEM-265. The spacing of these residues approximates a 3.5-residue repeat, suggesting that MEM-265 may recognize the epitope in an alpha-helical conformation. In the folded, peptide-loaded DR1 structure, the beta-chain residues 50-67 contain a kinked alpha-helical segment spanning Glu-52-Ser-63 (2). However, the conformation of this segment in the peptide-free form is unknown. We have used a new surface plasmon resonance approach in a SpotMatrix format to compare the kinetic rates and affinities for 18 alanine scanning mutants comprising epitope residues 50-67. In addition to the six essential residues described previously, we found two additional residues, Glu-52 and Gln-64, that contribute by enhancing MEM-265 binding. By contrast, mutation of either Gly-54 or Pro-56 to an alanine actually improved binding to MEM-265. In essentially all cases peptide substitutions that either improve or reduce MEM-265 recognition could be traced to differences in the dissociation rate (k off). The kinetic details of the present study support the presence of a structural component in the antigenic epitope recognized by MEM-265 in the peptide-free form of major histocompatibility complex II DR1 beta-chain.     

Marked mitochondrial DNA depletion associated with a novel SUCLG1 gene mutation resulting in lethal neonatal acidosis,multi-organ failure,and interrupted aortic arch

The aim of this study was to identify the causative genetic lesion in two apparently unrelated newborns having lethal lactic acidosis, multi-organ failure and congenital malformations including interrupted aortic arch, who exhibited mild methylmalonic aciduria, combined mitochondrial respiratory chain deficiency, and marked muscle mitochondrial DNA depletion. A novel mutation in the SUCLG1 gene was identified. Phenotype severity in Succinate-CoA ligase dysfunction appears to be more correlated to the muscle mtDNA content than to the tissue distribution of the heterodimer subunits. Prominent impairment of mitochondrial respiratory chain may result in deep ravages in developmental tissues leading to multiple organ failure and malformations.     

Cardioprotection by chronic estrogen or superoxide dismutase mimetic treatment in the aged female rat

Aging and estrogen deficiency increase the risk for developing cardiovascular disease (CVD). Oxidative stress has also been implicated in the pathophysiology of CVD and in ischemia-reperfusion (I/R) injury. We tested the hypothesis that chronic in vivo estrogen treatment or superoxide inhibition with the SOD mimetic EUK-8 improves cardiac functional recovery after I/R in the aged female rat. Sprague-Dawley rats (12-14 mo) were used as follows: intact (n = 6), ovariectomized + placebo (OVX, n = 6), OVX + EUK-8 (EUK-8, 3 mg/kg, n = 6), and OVX + estrogen (1.5 mg/pellet, 60 days release, n = 6). Perfused isolated hearts were subjected to global ischemia (25 min) followed by reperfusion (40 min). Functional recovery after I/R and myocardial protein expression of NADPH oxidase (p22, p67, and gp91(phox)), inducible nitric oxide synthase (NOS), endothelial NOS, and SOD1, as well as nitrotyrosine levels (as a marker for peroxynitrite), were assessed. Compared with OVX, EUK-8 and estrogen markedly improved functional recovery after I/R, which was associated with a decrease in NADPH oxidase expression and nitrotyrosine staining. However, estrogen increased inducible NOS expression, whereas EUK-8 had little effect. There were no significant changes in endothelial NOS and SOD1 expression among the groups. These results indicate that EUK-8 and estrogen improved cardiac recovery after I/R. Given the controversy surrounding hormone replacement therapy, EUK-8 may be an alternative to estrogen in protecting those at risk for myocardial ischemia in the aging population.