Loss of Symbiodinium from bleached soft corals Sarcophyton ehrenbergi, Sinularia sp. and Xenia sp.

The deleterious effects of temperature-induced coral bleaching, a process by which corals lose their endosymbiotic algae (zooxanthellae; genus Symbiodinium) primarily at temperatures above mean yearly maximums, has not been well described for alcyonacean soft corals (Coelenterata, Octocorallia). The study of Symbiodinium cells lost from Sarcophyton ehrenbergi, Sinularia sp., and Xenia sp., which have not been compared in bleaching studies, indicate that the soft coral S. ehrenbergi released the greatest number of symbiont cells, however, it was less susceptible to heat stress surviving temperatures of 34 °C for >39 h. Sinularia sp. showed intermediate levels of bleaching tolerance to elevated temperatures, surviving prolonged exposures at 32 °C, but dying within 24 h at 34 °C. Xenia sp., however, was the most vulnerable to high heat stress maximally releasing Symbiodinium at temperatures ≤30 °C. This evidence indicates that Xenia sp. is even more susceptible to elevated temperatures than Acropora spp., previously reported to be the most vulnerable coral species to elevated temperature-induced bleaching.

Molecular analysis showed that the more resistant soft coral species (S. ehrenbergi) had the same type of Symbiodinium (clade C) as less resistant soft corals (Xenia sp.). In comparison to scleractinian corals collected from the same region that show similar bleaching resistance to high temperatures (e.g. Porities solida—more robust; Favites complanata—moderate resistance; Acropora hyacinthus—less robust), all scleractinian corals were symbiotic with Symbiodinium from clade C. A. hyacinthus, however, was found to possess multiple symbionts (clades B and C), and this represents a first report of Clade B in any Acropora species.     

极小种群野生植物黄梅秤锤树群落结构与动态

本文以极小种群野生植物黄梅秤锤树(Sinojackia huangmeiensis)当前唯一的野生种群为依托建立了1 ha的固定样地, 研究了黄梅秤锤树野生植物群落的物种组成、优势种的径级结构、黄梅秤锤树的空间分布格局、种内与种间空间关联性和种群更新特征。样地内共记录到胸径 ≥ 1.0 cm的木本植物31种, 隶属于21科28属。群落更新良好, 样地中所有1,225株个体中小径木占比为67.18%。群落优势种为麻栎(Quercus acutissima)、枸骨(Ilex cornuta)、朴树(Celtis sinensis)和黄梅秤锤树。麻栎的径级结构呈单峰型, 为衰退型种群; 枸骨、朴树和黄梅秤锤树的径级结构呈倒“J”型或偏倒“J”型, 表明更新良好。黄梅秤锤树的空间分布格局在小尺度上呈聚集分布, 在大尺度上呈随机或均匀分布, 并且与其他3个优势种(麻栎、枸骨、朴树)在空间上主要呈负关联性。黄梅秤锤树的成树和幼苗、幼树和幼苗都是在小尺度上呈负关联性, 在大尺度上关联性不显著, 而成树和幼树在整体上关联性不显著。黄梅秤锤树的萌蘖现象非常明显, 萌蘖数与母株胸径具有极显著的正相关性(R² = 0.330, P < 0.001), 萌蘖率与相对幼苗密度具有极显著的负相关性(R² = 0.438, P < 0.001)。总体来说, 高比例的小径木和普遍的种间负关联均表明该群落处于演替的早中期, 物种组成和群落结构还未达到稳定阶段。作为长江中下游冲积平原区具有代表性的残存风水林, 该野生植物群落在生物多样性维持和珍稀植物保护方面具有重要的作用, 应加强保护和管理。     

Effect of epiphytes on the extent of necrotic injuries of resistant and susceptible poplar clones infected with Dothichiza populea.

Poplar cuttings of a resistant clone, Populus ‘Grandis’, and susceptible clones, Populus nigra ‘Italica’ and Populus ‘Robusta’, were infected with the pathogenic fungus Dothichiza populea alone, or with the pathogen and one of five strains of epiphytes antagonistic towards it (in vitro), isolated from poplar bark. The extent of injury was examined for 28 days after infection by determining the length of necrotic patches and their area as expressed in per cent of the total area of a cutting or the area of necrotic injuries caused by the pathogen alone.

All the poplar cuttings of both the resistant and susceptible clones became diseased when infected with the pathogen alone. Surprisingly enough, however, the least affected clone was the susceptible P. ‘Robusta’, in which necrotic injuries covered 28% of the total area, as against 40% and 70% in the resistant P. ‘Grandis’ and the susceptible P. nigra ‘Italica’, respectively.

When the cuttings were infected simultaneously with Dothichiza populea and its antagonistic epiphytes, the diseased area in the resistant clone diminished by as much as two-thirds, and in the susceptible P. nigra ‘Italica’, by one-third in comparison with the area affected by the pathogen alone. In turn, in the susceptible P. ‘Robusta’ the introduction of three out of five epiphytes stimulated the growth of the pathogenic fungus producing on average a double increase in the necrotic area. The differences in the response of the pathogen to the presence of epiphytes recorded in the susceptible clones indicate a marked influence of the plant on the nature of interactions between its epiphytic microflora and the pathogen.     

Competition between scleractinian corals and macroalgae: An experimental investigation of coral growth, survival and reproduction

Macroalgae are a major component of many coral reef flat communities, and are potentially major competitors with corals. The influence of macroalgae on several demographic parameters of four species of scleractinian coral by means of an algal clearance experiment was examined to determine specifically if macroalgae are affecting coral cover, growth, fecundity, fission, survivorship and recruitment. Also investigated were patterns of natural encounters between corals and algae.

Algal cover at the study site ranged from 41 to 56%, and coral cover from 8 to 10%. In total, 92 ± 4 ( )% of coral colonies were in contact with one or more species of macroalgae. Changes in coral cover were significantly affected by the presence of macroalgae, with cover of Acropora species increasing faster in areas from which algae had been cleared compared to control areas where algae had not been removed, although this pattern did not occur for Pocillopora damicornis (Linnaeus). Similarly, growth of individual colonies was faster when macroalgae were absent for three Acropora species but not for P. damicornis. There were no differences detected in rates of fission or survivorship of corals between algal clearance and control treatments, although there were high levels of variability in both of these parameters. Fecundity of Acropora palifera (Lamarck), the only species examined, was approximately double in colonies in cleared plots compared to those in control plots with macroalgae present. As no recruitment occurred throughout the 2-yr study, it remains to be determined how macroalgae effect the settlement of coral larvae. The results show that macroalgae can have a major influence on the demography of scleractinian corals.     

Drought stress induced changes in some organic substances in nodules and other plant parts of two potential legumes differing in salt tolerance

A greenhouse experiment was conducted to assess the effect of water stress on growth and metabolic changes in nodules and other plant parts of two leguminous species, Phaseolus vulgaris and Sesbania aculeata, with the major objective that nodules play a vital role in drought tolerance. Imposition of water deficit conditions for 45 days to 15-day-old plants of P. vulgaris and S. aculeata reduced shoot mass and nodule mass of both species, but the reduction was more pronounced in P. vulgaris than in S. aculeata. Nitrate reductase (NR) activity was reduced more in the leaves and nodules of P. vulgaris than in S. aculeata. Soluble proteins in the nodules of S. aculeata were more decreased as compared to that in P. vulgaris. Free amino acids increased in all parts of both species due to water deficit, but a higher increase was observed in leaf and nodules of P. vulgaris than in S. aculeata. Osmoprotectants such as proline and glycine betaine increased more in the nodules and other parts of S. aculeata under drought stress. In conclusion, S. aculeata (salt tolerant) showed a higher degree of drought tolerance than P. vulgaris (salt sensitive). Drought tolerance of S. aculeata was found to be associated with a smaller reduction in number and mass of root nodules, a high activity of nitrate reductase in leaves and nodules, high accumulation of free proline in roots and nodules, and high glycine betaine content in nodules.     

胶州湾滨海湿地土壤有机碳时空分布及储量

在胶州湾选取芦苇、碱蓬、光滩及大米草4种典型滨海湿地类型,分季节和层次采集土壤样品,测定土壤有机碳含量,分析滨海湿地土壤有机碳的时空分布及储量.结果表明: 垂直方向上,除光滩湿地沿剖面呈先减小后稍有上升的趋势外,其他湿地均随土壤深度的增加而减小;水平方向上,湿地土壤有机碳含量表现为大米草湿地>光滩湿地>碱蓬湿地>芦苇湿地;季节上,湿地土壤有机碳含量表现为春季>夏季>秋季>冬季.土壤有机碳含量与土壤含盐量、含水率、TN及C/N呈正相关,与土壤容重、pH值呈负相关.不同类型湿地土壤剖面有机碳密度表现为光滩湿地>芦苇湿地>碱蓬湿地,湿地类型对土壤有机碳含量和有机碳密度分布的影响存在一定差异.因储碳层厚度及储碳层内有机碳密度的差异,光滩湿地单位面积有机碳储量明显高于碱蓬和芦苇湿地,具有较大的储碳潜能,对研究区滨海湿地起到一定的碳汇作用.     

亚热带红壤侵蚀区马尾松不同套种模式生态系统碳平衡

以福建省长汀县红壤侵蚀区马尾松低效林套种杨梅、无患子、油茶及黄栀子的改造模式林分为研究对象,对林分各组分生物量年净生长量、含碳率及土壤异养呼吸进行定位观测,分析套种模式对低效马尾松林分生态系统碳储量格局及碳平衡的影响.结果 表明:杨梅、无患子、油茶、黄栀子和马尾松不同器官含碳率的变化范围分别为41.1％～ 50.1％、...     

Comparison of the physiological responses of Phaseolus vulgaris and Vigna unguiculata cultivars when submitted to drought conditions

Three cultivars differing in their susceptibility to water stress were compared—Phaseolus vulgaris cv. Carioca (susceptible), Vigna unguiculata cv. IT83D (intermediately tolerant) and V. unguiculata cv. EPACE-1 (tolerant)—during an imposed water stress treatment. Variation in leaf gas exchange (i.e. assimilation and stomatal conductance) and leaf relative water content in response to progressive substrate water depletion were investigated. To verify the extent of the injury caused by the drought treatment, leaf gas exchange was measured after rehydration. In the three cultivars, stomatal conductance declined before leaf relative water content was affected. P. vulgaris showed the largest decrease in the rate of stomatal conductance with decreasing substrate water content compared to both V. unguiculata cultivars. Photosynthetic assimilation rates were largely dependent on stomatal aperture, but there was evidence of the participation of non-stomatal factors in the reduction of CO₂ fixation. The response of leaf gas exchange parameters to severe water stress conditions differed significantly between P. vulgaris and V. unguiculata cultivars. After rehydration, cultivars can be characterised according to the degree of injury induced by the drought treatment: V. unguiculata cv. EPACE-1 as the least affected, V. unguiculata cv. IT83D slightly affected and P. vulgaris cv. Carioca strongly affected. Similar ranking was obtained with experiments previously performed at a cellular and subcellular level. Our results confirm the utility of physiological parameters as early screening tools for drought resistance in bean cultivars.     

The effects of short-term exposures to ultraviolet radiation in the Hawaiian Coral Montipora verrucosa

Exposure to ultraviolet radiation (UVR, 290–400 nm) is an important abiotic factor that tropical marine organisms have been exposed to over evolutionary time. Additionally, UVR is known to cause coral bleaching independently and is an important synergistic factor in bleaching caused by thermal stress. Corals can avoid some of the damage associated with exposure to UVR by producing UVR-absorbing compounds such as mycosporine-like amino acids (MAAs). To examine the role of MAAs in the UVR photobiology of corals we conducted experiments on the Hawaiian coral Montipora verrucosa. M. verrucosa colonies were collected from 1, 5 and 10 m and exposed to three different UVR treatments for 3 days under constant visible irradiances equivalent to a depth of 0.15 m depth in Kane'ohe Bay. In addition to quantifying the MAA concentration of these corals several types of UVR-induced damage were measured to assess whether MAAs were providing protection. Quantum yields of photosystem II (PSII) fluorescence and excitation pressure on PSII were measured for each coral, and the formation of direct UVR damage to DNA was measured as cyclobutane pyrimidine dimers (CPDs) and (6-4) pyrimidine–pyrimidone photoproducts for the holobiont. All corals exhibited midday depressions in quantum yields, developed DNA photoproducts, and increased their MAA concentrations significantly as a result of UVR exposures. CPD accumulation in M. verrucosa was highest in corals from 1 m, which had the lowest MAA concentrations at the end of the experiment. Corals originally from 10 m showed the highest MAA concentration and lowest DNA damage in response to exposure to UVR. While corals from all collection depths displayed some sensitivity to increased irradiances of UVR, their respective levels of tolerance were clearly dependant on their previous light history.     

天山雪岭云杉森林群落的密度制约效应

密度制约是维持自然森林群落物种共存的重要机制之一。雪岭云杉(Picea schrenkiana)是天山森林群落的单优种, 在我国温带森林中占有重要地位。本文基于对天山雪岭云杉8 ha森林动态监测样地的两次调查结果, 分析了该样地群落物种组成的动态变化, 运用点格局方法分析了雪岭云杉个体在不同龄级的空间分布格局及其关联性, 探讨了该群落的密度制约效应。结果表明: (1)该样地内, DBH ≥ 1 cm的木本植物在2009年有11,835株, 2014年为11,050株, 5年间的个体死亡率为8.82%, 补员率为2.19%, 个体株数净减少6.63%。(2)使用双关联函数g(r)分析了不同龄级雪岭云杉的空间分布格局, 发现幼龄树和中龄树在0-40 m尺度上主要呈现聚集分布, 但随着尺度增大聚集强度逐渐减小; 老龄树在0-2 m及4 m尺度上呈随机分布, 在其他尺度上呈聚集分布, 但聚集程度较小。(3)用“案例-对照”设计的方法, 排除生境异质性的影响后, 将幼龄树和中龄树作为案例, 老龄树作为对照, 对比幼龄树、中龄树与老龄树的分布格局, 发现雪岭云杉幼龄树和中龄树在0-40 m尺度上呈现额外的聚集, 随着径级的增大, 这种额外的聚集强度逐渐减小, 即表现出密度制约效应。(4)老龄树与中龄树、幼龄树的空间关联性相同, 在0-40 m尺度上均呈明显负关联。     

红花尔基樟子松优良抗旱菌树组合的筛选

为筛选红花尔基樟子松（Pinus sylvestris var.mongolica）优良抗旱菌树组合,采用樟子松林下5个优势外生菌根真菌菌株为接种体,分别对5个月龄樟子松实生苗进行人工接种,接种8个月后观察菌根侵染情况及菌根形态,并在非干旱胁迫和干旱胁迫条件下测定不同菌树组合的生长和生理生化指标。结果表明：5个乡土菌种均能成功侵染樟子松并形成典型的外生菌根;干旱胁迫下,菌根化樟子松的各项生长指标均显著高于对照（P<0.05）,且接种粘盖牛肝菌（Suillus bovinus）具有最高的菌根侵染率、苗高、地上及地下生物量和根茎比;外生菌根共生体可通过提高植物SOD活性与POD活性,同时降低MDA含量来提高樟子松对干旱的耐受力;干旱胁迫下,所有接种处理苗木的萎蔫时间较对照处理均推迟,推迟时间最长的是粘盖牛肝菌接种处理,较对照推迟96.3 h;另外,接种处理均能显著延长宿主临界致死时间,尤其是接种粘盖牛肝菌可延长113.8 h。因此,可以认为粘盖牛肝菌与樟子松是一个较为理想的抗旱菌树组合。     

Baltic amber fossils reveal early evolution of sexual dimorphism in stalk-eyed flies (Diptera: Diopsidae)

A cladistic analysis of 16 species of extant and amber fossil stalk-eyed flies of the family Diopsidae places the fossil †Prosphyracephala succini (Loew) as the sister group of all other Diopsinae, the subfamily in which eye stalks occur. The study is based on a scoring including five old and 23 new finds of †P. succini from Baltic amber, and for the first time allows a morphometric analysis of eye span and various body size parameters in this species. The data indicate that sexual dimorphism of the eye stalks already existed in †Prosphyracephala, suggesting that this feature evolved early in the Diopsinae. Contrary to recent views that the ancestral condition of diopsine eye stalks was monomorphic, the new results suggest that sexual selection was involved in the evolution of eye stalks from the very beginning of the lineage.     

The radiation of the Seicercus burkii complex and its congeners (Aves: Sylviidae): molecular genetics and bioacoustics

Cryptic species of passerine birds lack notable morphological differentiation and can best be identified by molecular and bioacoustic markers. Here we investigate seven cryptic species of the golden-spectacled warbler (Seicercus burkii complex) with respect to territorial song and cytochrome-b (cyt-b) sequences. Their phylogenetic relations to other Seicercus species and to members of the genus Phylloscopus are inferred by the same methods. Three separate lineages of Seicercus are nested within different branches of the molecular Phylloscopus tree. The S. burkii complex is a monophyletic unit comprising seven species (S. burkii s. str., S. whistleri, S. valentini, S. soror, S. omeiensis, S. tephrocephalus and S. affinis). S. xanthoschistos turned out to be a close relative of Phylloscopus davisoni within the P. reguloides group. Two isolated sister taxa, S. grammiceps and S. castaniceps, also branch together with the P. reguloides group. Within the S. burkii complex the overall haplotype and nucleotide diversity is highest in taxa from the Chinese middle and upper mountain belt (S. valentini, S. omeiensis and S. soror), indicating at least partially restricted gene flow in these species. This is explained by the fragmentation of high-altitude habitats in China while in the Himalayas the vicariant species S. whistleri inhabits a more continuous mountain belt at the same altitude. For the Chinese species from medium and high altitudes, past range expansion is indicated by significantly negative Tajima Ds. According to pairwise genetic distances, most species of the S. burkii complex have diverged 5 myr ago, the most recent split between S. burkii and S. tephrocephalus is dated 2 myr ago. Coalescence times for haplotype lineages of the different species range from 9 up to 12 myr, and between 5 and 6 myr for S. burkii and S. tephrocephalus.

Within Seicercus divergence of song features such as frequency parameters and syntax structures correlate with genetic distances between taxa. The three cyt-b lineages of Seicercus correspond to different clusters in a discriminant analysis by acoustic parameters. Common syntax structures of territorial song in the Phylloscopus/Seicercus assemblage are: (1) an introductory element derived from specific calls and (2) a syntax of trills and repeated element groups or a combination of both. There are clear indications that these song structures have repeatedly emerged, were lost or were altered in different branches of the phylogenetic tree at different times. Absolute differences between taxa in frequency parameters or in an acoustic divergence index increase significantly with growing genetic distances. However, due to multiple parallel evolution phylogenetic information provided by single acoustic traits decreases with increasing numbers of taxa involved in the investigation.     

土著昆虫素毒蛾在本地植物芦苇与入侵植物互花米草上的生活史

互花米草(Spartina alterniflora)入侵盐沼生态系统导致了土著广食性昆虫素毒蛾(Laelia coenosa)发生宿主转移。但是, 目前对素毒蛾在互花米草和芦苇(Phragmites australis)上的生活史规律的比较尚未见报道, 而此信息对评价素毒蛾能否持续利用互花米草具有重要的参考价值。为了明确素毒蛾在其原始宿主芦苇和外来新宿主互花米草上的生活史动态, 我们在上海崇明长江口盐沼湿地中, 对素毒蛾在芦苇和互花米草生境中的发生情况进行了系统调查。结果显示, 虽然素毒蛾在芦苇和互花米草上均一年发生3代, 并都以幼虫越冬, 但在互花米草生境中, 越冬代幼虫开始越冬的时间要比芦苇中晚20 d左右, 其他世代中的多个虫态在互花米草上持续出现的时间也比芦苇上延迟了约10 d。这些结果表明, 互花米草入侵后素毒蛾在外来植物上出现的持续时间虽然发生了延长, 但其年世代数未变化。我们推测素毒蛾在互花米草和芦苇上生长发育规律的差异可能受生境的资源可利用性及两种植物的营养与防御水平调控。     

褐环乳牛肝菌对樟子松和油松根际土壤真菌多样性的影响

为了解褐环乳牛肝菌Suillus luteus对樟子松Pinus sylvestris var. mongolica和油松Pinus tabulaeformis根际土壤真菌群落结构的影响,采用Illumina MiSeq高通量测序,对两种松树接种S. luteus与对照组的根际土壤真菌群落结构进行研究。结果显示,4个样品共获得原始序列347 681条,归为5个真菌门。综合各土壤样品真菌Alpha多样性指数及OTUs-Venn图,发现接种S. luteus后樟子松和油松根际土壤真菌相对丰度与对照存在一定差异。群落结构分析表明,接种S. luteus提高了樟子松和油松根际土壤担子菌和壶菌的相对丰度,抑制了子囊菌门真菌。优势属由原来的Geopora转变为Suillus。通过PCA分析与NMDS分析发现接种S. luteus后樟子松和油松根际土壤真菌群落差异性增加,且接种S. luteus后樟子松根际土壤真菌群落结构相似性显著高于油松根际土壤真菌群落结构相似性。接种S. luteus的樟子松和油松土壤真菌丰富度降低、多样性增加,接种S. luteus改变了樟子松和油松根际土壤真菌群落结构和优势真菌种群。试验结果为樟子松和油松促生真菌菌种筛选和育苗工作提供了依据。     

Estuarine pufferfishes (Sphoeroides testudineus and S. Greeleyi) submitted to sea water dilution during ebb tide: a field experiment

The pufferfishes Spheroides testudineus and S. greeleyi are very abundant in estuaries along the Brazilian coast, with S. greeleyi restricted to areas of higher salinity than S. testudineus. Their osmoregulatory behaviour was tested with the fish inside fixed cages in the estuary, forced to endure sea water dilution during ebb tide. Fish were sampled when sallinity naturally decreased to 29.5‰, 14‰, and 4.5‰, along 5-6 hours. Plasma osmolality and chloride concentration were well regulated by the fish S. greeleyi displayed higher values than S. testudineus, and showed mortality at the lowest salinity, compatible with the ecological observation of the more frequent presence of S. testudineus in very dilute sea water.     

Patterns of habitat and food utilization in two coral-reef sandperches (Mugiloididae): competitive or noncompetitive coexistence?

Use of food and habitat of the two sympatric, territorial mugiloidid fishes Parapercis polyophthalma (Cuvier) and P. clathrata Ogilby, which have similar body size and morphology, were examined in the fringing coral reef area at Iriomote Island, one of the Ryukyu Islands of Japan. Both species preyed mainly on decapod crustaceans, and the dietary overlap value was intermediate (0.528). Differences in resource utilization between the two species were conspicuous in habitat rather than in food. ≈60% of the P. polyophthalma population was found on sandy flats of the reef flat zone, while > 90 % of the P. clathrata population occurred at channel areas. In addition to this macrohabitat segregation, both species showed a substantial microhabitat separation at channels where they coexisted with nearly the same densities: P. polyophthalma was numerically dominant on a sandy rubble substratum, whereas P. clathrata was abundant on a rubble substratum. A reciprocal removal experiment demonstrated that this microhabitat separation was an outcome of current competitive interactions between them. P. polyophthalma is an aggressively dominant species and so can predominantly occupy its optimal microhabitat i.e., sandy rubble substratum, at channels, while the subordinate P. clathrata is constrained to shift its microhabitat to a rubble substratum unsuitable for the dominant. Although a density-manipulation experiment for the macrohabitat segregation was not carried out in this study, circumstantial evidence suggested that the segregation is probably attributable to differences in habitat adaptation between the species which need not be the consequence of competition. These results indicate that the structure of the two-species guild may be determined by both competitive and noncompetitive mechanisms.     

Palaeobiology and evolution of the earliest agglutinated Foraminifera: Platysolenites, Spirosolenites and related forms

Tubular agglutinated fossils of Platysolenites antiquissimus Eichwald, 1860, P. cooperi n.sp. and Spirosolenites spiralis Glaessner, 1979 are examined from selected lower Cambrian successions in Avalonia (England; Wales; Newfoundland) and Baltica (Russia and Estonia). Platysolenites cooperi n.sp. is shown to extend below the first appearance of P. antiquissimus in the Neoproterozoic-Cambrian boundary stratotype region, SE Newfoundland, and to occur at higher stratigraphic levels in Wales and Finnmark. Taphonomic, teleological and ultrastructural studies on well-preserved material are consistent with a similar grade of organization and mode of life for P. antiquissimus and the living astrorhizacean foraminiferid Bathysiphon. However, agglutinated proloculi are here described from both rectilinear P. antiquissimus and coiled S. spiralis, which suggests that neither were typical astrorhizaceans.     

An inducible release of reactive oxygen radicals in four species of gorgonian corals

The capability for physical injury or heat stress to elicit the production of reactive oxygen species was examined in four species of gorgonian corals. The sea plumes Pseudopterogorgia elisabethae, Pseudopterogorgia americana, the sea rod Eunicea fusca and the azooxanthellate red branching gorgonian Lophogorgia chilensis were physically injured using sonic sound cavitations and heat shocked by incubation in 33°C sea water. The pharmacological probe, diphenylene iodonium chloride (DPI), an inhibitor of NAD(P)H oxidase and peroxidases was used to identify an enzymatic surrogate of the oxidative burst. Both injury and heat stress were capable of inducing the release of reactive oxygen species (ROS) in all gorgonians tested, yet the kinetics and amplitude of ROS release varied among genera. In both the treatments, P. americana demonstrated the largest oxidative burst among the other corals tested.     

The property of DNA polymerase zeta: REV7 is a putative protein involved in translesion DNA synthesis and cell cycle control

Translesion DNA synthesis (TLS) is an important damage tolerance system which rescues cells from severe injuries caused by DNA damage. Specialized low fidelity DNA polymerases in this system synthesize DNA past lesions on the template DNA strand, that replicative DNA polymerases are usually unable to pass through. However, in compensation for cell survival, most polymerases in this system are potentially mutagenic and sometimes introduce mutations in the next generation. In yeast Saccharomyces cerevisiae (S. cerevisiae), DNA polymerase ζ, which consists of Rev3 and Rev7 proteins, and Rev1 are known to be involved in most damage-induced and spontaneous mutations. The human homologs of S. cerevisiae REV1, REV3, and REV7 were identified, and it is revealed that the human REV proteins have similar functions to their yeast counterparts, however, a large part of the mechanisms of mutagenesis employing REV proteins are still unclear. Recently, the new findings about REV proteins were reported, which showed that REV7 interacts not only with REV3 but also with REV1 in human and that REV7 is involved in cell cycle control in Xenopus. These findings give us a new point of view for further investigation about REV proteins. Recent studies of REV proteins are summarized and several points are discussed.