Dopaminergic Mechanisms in the Teleost Retina

A specific dopamine-sensitive adenylate cyclase has been identified in homogenates of the teleost (carp) retina. Maximal stimulation by 100 microM-dopamine resulted in a 5--10-fold increase in adenylate cyclase activity with half-maximal stimulation occurring at a concentration of 1 microM. l-Noradrenaline and l-adrenaline were some 10 times less potent than dopamine whilst the alpha- and beta-adrenoreceptor agonists, l-phenylephrine and dl-isoprenaline were inactive. Apomorphine elicited a partial stimulation of adenylate cyclase activity whilst various ergot alkaloids produced mixed agonist/antagonist responses. Dopamine-stimulated adenylate cyclase activity was potently antagonised by various neuroleptic drugs including fluphenazine, alpha-flupenthixol and alpha-piflutixol, and to a lesser extent by the butyrophenone derivatives haloperidol and spiperone. The benzamide derivatives, metoclopramide and sulpiride, together with the alpha- and beta-adrenoreceptor blocking agents, phentolamine and propranolol respectively were essentially inactive at blocking dopamine-stimulated adenylate cyclase activity. These data suggest the presence of a highly specific dopamine-sensitive adenylate cyclase in homogenates of teleost retina possessing similar pharmacological properties to the dopamine-sensitive adenylate cyclase observed in the mammalian central nervous system.     

Efficacy of Phospholipid Analysis in Determining Microbial Biomass in Sediments

Improvements in the analysis of lipid-bound phosphates resulted in a simplified and sensitive method for determining microbial biomass in sediments. Sensitivity was enhanced over previous methods by use of a dye, malachite green, which when complexed with phosphomolybdate at low pH has a high extinction coefficient (at 610 nm). The use of a persulfate oxidation technique to liberate phosphate from lipids increased the simplicity and safety of the method relative to the traditional perchloric acid digestions. The modified method was both accurate (yielding quantitative recoveries of cells added to sediments) and precise (coefficient of variation of less than 5% for cells and sediments). A comparison with an epifluorescence technique indicated that the analysis of lipid-bound phosphate was more rapid and less tedious and could be successfully applied to a wider variety of sediment types. An estimate of the lipid-bound phosphate-to-carbon conversion factor based on a diverse enrichment culture from sediments suggested that previous factors for pure cultures may have been too low.     

Global diversity and distribution of macrofungi

Data on macrofungal diversity and distribution patterns were compiled for major geographical regions of the world. Macrofungi are defined here to include ascomycetes and basidiomycetes with large, easily observed spore-bearing structures that form above or below ground. Each coauthor either provided data on a particular taxonomic group of macrofungi or information on the macrofungi of a specific geographic area. We then employed a meta-analysis to investigate species overlaps between areas, levels of endemism, centers of diversity, and estimated percent of species known for each taxonomic group for each geographic area and for the combined macrofungal data set. Thus, the study provides both a meta-analysis of current data and a gap assessment to help identify research needs. In all, 21,679 names of macrofungi were compiled. The percentage of unique names for each region ranged from 37% for temperate Asia to 72% for Australasia. Approximately 35,000 macrofungal species were estimated to be “unknown” by the contributing authors. This would give an estimated total of 56,679 macrofungi. Our compiled species list does not include data from most of S.E. Europe, Africa, western Asia, or tropical eastern Asia. Even so, combining our list of names with the estimates from contributing authors is in line with our calculated estimate of between 53,000 and 110,000 macrofungal species derived using plant/macrofungal species ratio data. The estimates developed in this study are consistent with a hypothesis of high overall fungal species diversity.     

A JAK1/JAK2 chimera can sustain alpha and gamma interferon responses.

Cell lines that are mutated in interferon (IFN) responses have been critical in establishing an essential role for the JAK family of nonreceptor tyrosine kinases in interferon signalling. Mutant gamma1A cells have previously been shown to be complemented by overexpression of JAK2. Here, it is shown that these cells carry a defect in, and can also be complemented by, the beta-subunit of the IFN-gamma receptor, consistent with the hypothesis that the mutation in these cells affects JAK2-receptor association. In contrast, mutant gamma2A cells lack detectable JAK2 mRNA and protein. By using gamma2A cells, the role of various domains and conserved tyrosine residues of JAK2 in IFN-gamma signalling was examined. Individual mutation of six conserved tyrosine residues, mutation of a potential phosphatase binding site, or mutation of the arginine residue in the proposed SH2-like domain had no apparent effect on signalling in response to IFN-gamma. Results with deletion mutants, however, indicated that association of JAK2 with the IFN-gammaR2 subunit requires the amino-terminal region but not the pseudokinase domain. Consistent with this, in chimeras with JAK1, the JAK2 amino-terminal region was required for receptor association and STAT1 activation. Conversely, a JAK1-JAK2 chimera with the amino-terminal domains of JAK1 linked to the pseudokinase and kinase domains of JAK2 is capable of reconstituting JAK-STAT signalling in response to IFN-alpha and -gamma in mutant U4C cells lacking JAK1. The specificity of the JAKs may therefore lie mainly in their structural interaction with different receptor and signalling proteins rather than in the substrate specificity of their kinase domains.     

英国多克隐花植物保护区森林土壤和凋落叶特性及其与真菌的关系

报道了英国独特的真菌保护区里真菌的生态学和生物多样性,而该保护区内有关物种构成的数据自1994年就开始进行收集了。关于真菌的生态学相互关系以及它们在总的生态系统功能中的作用可以作为生物多样性数据的补充。5~8月期间,在8块覆盖着不同植被（山毛榉,桦树,桦栎山毛榉,禾本科植物）实验区里,研究了森林凋落叶和叶本层土壤的特性和构成,测量了细菌种群数量和真菌的生物量（针对麦角固醇而言）。用相关分析和分段回归建模方法,结合可通过并行研究采集到的原生动物和线虫数据,得到了一系列结果。这些结果强调了某些因素的复杂性,这些因素影响着森林土壤和森林凋落叶中真菌生物量空间可变性的时间动态。大多数的相互作用看起来是瞬时的,在解释环境观测记录时应该对这一点给予充分考虑。最后,解释了若干具体关系,给出了进一步研究的方向,讨论了对整个生态系统功能研究的必要性。     

PHOTOINHIBITION AND PHOTOACCLIMATION OF TURF ALGAL COMMUNITIES ON A TEMPERATE REEF,AFTER IN SITU TRANSPLANTATION EXPERIMENTS1

The photophysiology of turf algal communities was studied in situ on a temperate reef off the coast of South Australia. Algal communities were grown on artificial substrate at depths of 2, 4, and 10 m. To investigate the response of the algal communities to changing light environments in both the short and long term, reciprocal transplantation experiments were conducted among these depths on a seasonal basis. The extent of photoinhibition was assessed every 3 h for the first 2 days following transplantation and then on a daily basis for 16 days after transplantation. Photosynthetic acclimation was assessed using photosynthesis–light curves obtained from transplanted and non‐transplanted turfs after the acclimation period. Transplanted turfs responded very quickly to the light shift. Algae acclimated to low light (10 m depth) were highly susceptible to photoinhibition and photodamage, having greater decreases in maximum and effective quantum yields than turfs from shallower depths. Yield recovery and acclimation usually occurred very rapidly in algae from all depths (3–5 days), but were faster in spring and summer compared with winter. Changes in photosynthetic capacity (across seasons, depths, and after transplantation to a different depth) were accompanied by changes in respiration, so that the ratio of net to gross photosynthetic capacity (P_mnet : P_mgross) remained high and constant over the whole range of light levels. We discuss the possible acclimation strategies of turfs, taking into account the balance between photoacclimation, production, and growth strategy.     

Comparative Leaching of Chalcopyrite by Selected Acidophilic Bacteria and Archaea

A systematic study of the bioleaching of chalcopyrite (CuFeS 2 ) was conducted using axenic cultures of 11 species of acidophilic Bacteria and Archaea to obtain a direct comparison of the microbial chalcopyrite leaching capabilities of the different cultures and to determine the factors that affect Cu release. The characteristics of chalcopyrite leaching by the moderate thermophile Sulfobacillus thermosulfidooxidans , the mesophile Acidithiobacillus ferrooxidans , and the thermophile Acidianus brierleyi were used to elucidate the leaching process. Moderately thermophilic cultures of Sulfobacillus acidophilus, Acidimicrobium ferrooxidans , and Acidithiobacillus caldus were used to study the effects of different metabolic capabilities and relate those to leaching efficiency. The greatest rate of Cu solubilization from chalcopyrite was achieved at high temperatures (up to 70°C) at redox potentials below +550 mV (Ag/AgCl). The enhanced Cu solubilization observed at high temperatures resulted from accelerated chemical reaction rates, rather than from the rates at which individual acidophiles generated the mineral leaching reactants such as Fe 3+ .     

From principles to practice: a spatial approach to systematic conservation planning in the deep sea

Increases in the demand and price for industrial metals, combined with advances in technological capabilities have now made deep-sea mining more feasible and economically viable. In order to balance economic interests with the conservation of abyssal plain ecosystems, it is becoming increasingly important to develop a systematic approach to spatial management and zoning of the deep sea. Here, we describe an expert-driven systematic conservation planning process applied to inform science-based recommendations to the International Seabed Authority for a system of deep-sea marine protected areas (MPAs) to safeguard biodiversity and ecosystem function in an abyssal Pacific region targeted for nodule mining (e.g. the Clarion–Clipperton fracture zone, CCZ). Our use of geospatial analysis and expert opinion in forming the recommendations allowed us to stratify the proposed network by biophysical gradients, maximize the number of biologically unique seamounts within each subregion, and minimize socioeconomic impacts. The resulting proposal for an MPA network (nine replicate 400 × 400 km MPAs) covers 24% (1 440 000 km²) of the total CCZ planning region and serves as example of swift and pre-emptive conservation planning across an unprecedented area in the deep sea. As pressure from resource extraction increases in the future, the scientific guiding principles outlined in this research can serve as a basis for collaborative international approaches to ocean management.     

Notes on British Boleti: III.

Summary

A key to the British species of the genera Aureoboletus, Boletinus, Gyroporus, Phylloporus, Porphyrellus, Pulveroboletus, Strobilomyces and Uloporus based on habitat, microscopic and macroscopic features is discussed. Four species as yet unrecorded from the British Isles, Boletinus asiaticus, Xerocomus amarellus, Boletus vaccinus, Boletus badiorufus and seven species which could possibly be sought in one of these genera are included in the discussion for completeness; the latter are also included in the key.