Avaliação do efeito anti-inflamatório e antiasmático da 15-deoxy-delta-12,14-prostaglandina J2 em modelos murinos de asma

A asma é um distúrbio crônico pulmonar caracterizado por inflamação, obstrução e remodelamento brônquico, levando a sintomas como sibilo, tosse e falta de ar. A terapia antiasmática consiste em corticosteroides inalados e agonistas β2 de curta ou longa duração. O tratamento é limitado por efeitos colaterais e refratariedade de alguns pacientes, justificando a necessidade de novas terapias. Estudos demonstram que a 15-deoxy-delta- 12,14-prostaglandina J2 (15d-PGJ2), um ligante endógeno de receptores ativados por proliferadores de peroxissomos do tipo gama (PPAR-γ), é capaz de reduzir a expressão de citocinas pró-inflamatórias, o que pode resultar em benefícios no tratamento de doenças com esse perfil. O objetivo deste estudo foi avaliar o potencial anti-inflamatório e antiasmático da 15d-PGJ2 em modelos experimentais de asma. Camundongos A/J machos foram sensibilizados nos dias 0 e 7 através de injeção subcutânea (s.c.), contendo ovoalbumina (OVA) e Al(OH)3, e desafiados com 4 instilações intranasais (i.n.) de OVA em intervalos semanais. O tratamento com 15d-PGJ2 (30 e 100 g/Kg, s.c.) foi realizado 30 min antes dos desafios a partir da terceira provocação antigênica. Em outro modelo, camundongos A/J foram desafiados intranasalmente com extrato de ácaro 3 vezes por semana durante 3 semanas. As administrações de 15d-PGJ2 (30, 70 e 100 g/Kg, s.c. e 0,65; 1,5 e 2,3 g/animal, i.n.) foram realizadas a partir da 3 semana, 30 min antes dos desafios. As análises ocorreram 24 h após o último desafio. Nossos resultados mostraram que, em camundongos previamente sensibilizados e desafiados com OVA, a administração de 15d-PGJ2 limitou significativamente o influxo peribrônquico de eosinófilos e neutrófilos, bem como a produção de muco por células caliciformes e fibrose sub-epitelial, além da hiperreatividade das vias aéreas e produção de IL-5. A redução do epitélio brônquico e das citocinas IL-13 e TNF-α foram observadas somente na maior dose administrada. No modelo HDM a inflamação e o remodelamento foram atenuados em todas as doses administradas do composto, enquanto que a hiperresponssividade brônquica foi inibida apenas nas doses de 70 e 100 μg/Kg (via sistêmica) e na dose intermediária dada topicamente (1,5 μg/animal, i.n.). Os níveis de citocinas foram atenuados pelo tratamento subcutâneo, porém somente os níveis de IL-17, eotaxina-1 e TNF-α foram inibidos com a dose intranasal de 0,65 g/animal. O aumento da expressão de NF-κB, induzido por provocação com HDM também foi reduzido significativamente pela administração de 15d-PGJ2. Em conjunto, nossos dados indicam que o tratamento com 15d-PGJ2 inibe alterações cruciais associadas à patogênese da asma, em modelos experimentais distintos da doença, demonstrando possuir grande potencial para controlar e reverter inflamação, hiperreatividade e remodelamento pulmonar desencadeados por provocação alérgica.

Climatic factors associated with phytoplankton community succession during and after the 1977 drought for the San Francisco Bay-Delta Estuary [abstract]

Principal coordinates analysis and multiple regression analysis were used to determine the environmental factors associated with the decline in phytoplankton production during and after the 1977 drought for the San Francisco Bay-Delta Estuary. Physical, chemical and biological data were collected semimonthly or monthly during the spring-summer between 1973 and 1982 from 15 sampling sites located throughout the Bay-Delta. A decline in phytoplankton community diversity and density during the 1977 drought and subsequent years (1978 through 1981) was described using principal coordinates analysis. The best multiple regression which described the changes in phytoplankton community succession contained the variables water temperature, wind velocity and ortho-phosphate concentration. Together these variables accounted for 61 percent of the variation in the phytoplankton community among years described by principal coordinates analysis. An increase in water temperature, wind velocity and ortho-phosphate concentration within the Bay-Delta, beginning in June 1976 and continuing through 1981, was demonstrated using weighted moving averages. From the strong association between phytoplankton community succession and climatic variables it was hypothesized that the decline in phytoplankton production during and after the 1977 drought was associated with climatic changes within the northeast Pacific.

Associations among chlorophyll concentration and climatic variables for Suisun Bay and the Sacramento-San Joaquin Delta [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): The recent changes in phytoplankton production and community composition within the Suisun Bay and Sacramento-San Joaquin Delta may be related to climate. Chlorophyll a concentration, decreased by 42% (spring-summer) and 29% (fall) between 1972 through 1976 and 1977 through 1981. The decrease in biomass was characterized by a shift in phytoplankton community dominance from Skeletonema spp., Cyclotella spp. and Coscinodiscus spp. to Melosira granulata. The possible influence of climate on phytoplankton abundance was suggested by multivariate statistical analyses that demonstrated an association between changes in phytoplankton community composition and abundance between 1975 and 1982 and the climate related variables wind velocity, precipitation, river flow and water temperature.

伞形科囊瓣芹属的系统学研究

囊瓣芹属Pternopetalum Franchet是伞形科Apiaceae/Umbelliferae芹亚科Apioideae芹族Apieae重要成员。全属包括约32个分类群（包括变种），分布于南朝鲜、日本、中国的西南部和邻近的喜马拉雅地区，中国西南部的横断山区是其多样性中心。典型的东亚特有格局和对东亚亚热带森林环境的偏爱是其东亚区系故有份子的特征。 基于19个标本馆标本材料、野外调查以及相应的实验证据，本博士论文从三个研究主题对囊瓣芹属展开了全面而系统的研究。一是通过标本观察和野外调查，利用标本管理系统BRAHMS和表型分析软件包DELTA系统，完成了囊瓣芹属的世界性分类修订；二是基于上述的分类方案，选择伞形科其它属的44个种作为参考性类群（Reference taxa），利用Winclada, NONA和MESQUITE软件包开展了分支系统学研究；三是基于坐标化的点分布数据，利用DIVA-GIS系统的生态位模型，进行潜在分布预测和生态地理分布特征的分析。研究的主要初步结论如下： 一、分类修订 根据对19个标本馆标本材料（包括85个模式采集）的考证，以及对云南、四川、贵州等地野外居群的观察，结合DELTA系统的表型分析，本研究确认囊瓣芹属包含14个种，提出了14个新异名，属下分为东亚囊瓣芹组Sect. I. Pteridophyllae H. Wolff和囊瓣芹组Sect. II. Pternopetalum H. Wolff两个组的分类方案。前者包括东亚囊瓣芹P. tanakae (Sav. & Franchet) Hand.-Mazz.、高山囊瓣芹P. subalpinum Hand.-Mazz.、洱源囊瓣芹P. molle (Franchet) Hand.-Mazz.等5个种；后者包括五匹青P. vulgare (Dunn) Hand.-Mazz.、囊瓣芹P. davidii Franchet和澜沧囊瓣芹P. delavayi (Franchet) Hand.-Mazz.等9个种。萼齿、花柱基、和花柱的形态是区别两个组比较好的形态学特征。叶的着生位置、最终末回裂片的形状（是否异形）、分裂回数以及伞形花序着生的位置和果棱表面的附属构造是种间识别有用的检索特征。 二、系统发育分析 根据如上的14个种的分类方案，另外选取了伞形科小芹属Sinocarum H. Wolff、丝瓣芹属Acronema Falc. ex Edgew.和鸭儿芹属Cryptotaenia L.等10个属共44种作为参考类群，基于63个广义形态学性状和58个种的形态学矩阵，利用最大简约法对囊瓣芹属进行了分支分析。结果表明，囊瓣芹属的14个种与日本特有单型的仙洞草Chamaele decumbens (Thunb.)Makino.形成一个单独分支，处于分支图的基部位置。表明囊瓣芹属与鸭儿芹属有较近的亲缘关系。长枝吸引可能是造成Chamaele Miq.与东亚囊瓣芹分支的非正常聚合的原因。囊瓣芹属可能是单系内群，但它与Chamaele Miq.属间关系需要进一步研究。属下形成以五匹青P. vulgare和东亚囊瓣芹P. tanakae为代表的两个主干演化线。分支进化（Cladogenesis）在两个主干演化线形成了形态和地理上对称分布的“种对”。根据形态特征的变异和地理分布，这些“种对”分为三种类型：1、形态上多变而地理上广布的类型，以东亚囊瓣芹P. tanakae和五匹青P. vulgare为代表；2、形态上稳定地理上狭域特有的类型，以薄叶囊瓣芹P. leptophyllum (Dunn)Hand.-Mazz. 和川鄂囊瓣芹P. rosthornii (Diels) Hand.-Mazz.为代表；3、形态上趋同而多变，地理分布上几乎完全重叠的类型，以洱源囊瓣芹P. molle和澜沧囊瓣芹P. delavayi为代表。 性状状态的分析显示，属下形态特征的趋异具有较强的同朔性。不等长的伞辐和花梗，以及囊状的花瓣基部三个形态学特征可以标识包括仙洞草在内的囊瓣芹分支。祖征状态的重建表明，东亚囊瓣芹分支相对保留了更多的祖征，是属下相对原始的类型；五匹青分支是后期生境需求的特化，适应潮湿和荫蔽环境的衍生类型。 三、生态地理分布 基于1128个坐标化的点分布数据和生态位模型，利用地理信息系统软件包DIVA-GIS对囊瓣芹属的物种多样性、现代地理分布、潜在分布进行了分析。结果表明，二郎山-峨眉山地区以及重庆金佛山及其临近地区是囊瓣芹属的两个主要的多样性中心。分布区内局部尺度上的异常性多样性（Diversity abnormalies）可能有两个来源：一是高的异质性生境条件下物种形成速率的差异；二是中国西南山地的“冰原岛峰效应”（Nunataks），比如峨眉山和金佛山，对属的早期演化线成员所起到的“避难所”（Refuge）的作用。 所预测的潜在分布范围与观察到的地理分布范围是一致的，说明对特化的气候忍耐性是限制囊瓣芹属物种地理分布的主要因素。温度和降水的季节性变化对囊瓣芹属代表中的地理分布限制作用比较大。亚热带-高山针阔常绿林是属下物种比较适宜的生境。属的地理分布可能形成于中新世以后，生态位的保守性是解释囊瓣芹属东亚本土就地分化和多样化的原因。属的分布范围的形成可能经历了一个早期南退西进的过程，后期分布范围变化可能主要是东西方向上的迁移和扩展。喜马拉雅—横断山—峨眉山/金佛山/神农架—日本、南朝鲜一线是囊瓣芹属多样化过程中分布范围东西延伸的重要通道。喜马拉雅—中国西南—日本朝鲜亚热带森林植被的完整性和连续性是囊瓣芹属演化和分布区形成的基本条件。

Nutrient enhanced coastal ocean productivity in the north Gulf of Mexico: understanding the effects of nutrients on a coastal ecosystem

The continental shelf adjacent to the Mississippi River is a highly productive system, often referred to as the fertile fisheries crescent. This productivity is attributed to the effects of the river, especially nutrient delivery. In the later decades of the 2oth century, though, changes in the system were becoming evident. Nutrient loads were seen to be increasing and reports of hypoxia were becoming more frequent. During most recent summers, a broad area (up to 20,000 krn2) of near bottom, inner shelf waters immediately west of the Mississippi River delta becomes hypoxic (dissolved oxygen concentrations less than 2 mgll). In 1990, the Coastal Ocean Program of the National Oceanic and Atmospheric Administration initiated the Nutrient Enhanced Coastal Ocean Productivity (NECOP) study of this area to test the hypothesis that anthropogenic nutrient addition to the coastal ocean has contributed to coastal eutrophication with a significant impact on water quality. Three major goals of the study were to determine the degree to which coastal productivity in the region is enhanced by terrestrial nutrient input, to determine the impact of enhanced productivity on water quality, and to determine the fate of fixed carbon and its impact on living marine resources. The study involved 49 federal and academic scientists from 14 institutions and cost $9.7 million. Field work proceeded from 1990 through 1993 and analysis through 1996, although some analyses continue to this day. The Mississippi River system delivers, on average, 19,000 m3/s of water to the northern Gulf of Mexico. The major flood of the river system occurs in spring following snow melt in the upper drainage basin. This water reaches the Gulf of Mexico through the Mississippi River birdfoot delta and through the delta of the Atchafalaya River. Much of this water flows westward along the coast as a highly stratified coastal current, the Louisiana Coastal Current, isolated from the bottom by a strong halocline and from mid-shelf waters by a strong salinity front. This stratification maintains dissolved and particulate matter from the rivers, as well as recycled material, in a well-defined flow over the inner shelf. It also inhibits the downward mixing of oxygenated surface waters from the surface layer to the near bottom waters. This highly stratified flow is readily identifiable by its surface turbidity, as it carries much of the fine material delivered with the river discharge and resuspended by nearshore wave activity. A second significant contribution to the turbidity of the surface waters is due to phytoplankton in these waters. This turbidity reduces the solar radiation penetrating to depth through the water column. These two aspects of the coastal current, isolation of the inner shelf surface waters and maintenance of a turbid surface layer, precondition the waters for the development of near bottom summer hypoxia.