Curculionid beetles in aborted flower buds and immature fruits of <Emphasis Type="Italic">Ceiba</Emphasis><Emphasis Type="Italic">pentandra</Emphasis> (Bombacaceae)

We determined the incidence of curculionid beetles of the genus Lonchophorus on aborted and not aborted flower buds and developing fruits of the tree Ceiba pentandra in southeastern Costa Rica. Beetle larvae were found in reproductive parts of all trees sampled trees. The frequency of beetle larvae was greater in aborted buds and immature fruits. A positive correlation between larvae development and flower bud development indicates that female oviposition occurred in an early flower developmental stage and time until bud abortion is variable. Weevil herbivory could be considered as one of the main factors that cause flower bud and fruit abortion in C. pentandra.

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Resumen Determinamos la incidencia de curculiónidos del género Lonchophorus en botones florales y frutos inmaduros tanto abortados como no abortados en el árbol Ceiba pentandra en el SE de Costa Rica. Las larvas de curculiónidos fueron encontradas en todos los árboles muestreados. La frecuencia de larvas fue mayor en botones y frutos abortados. Una correlación positiva entre el desarrollo larval y el desarrollo del botón indica que la oviposición ocurre en una fase temprana de este y que el tiempo hasta el aborto es variable. La herbivoría por larvas de curculiónidos puede ser uno de los factores más importantes en el aborto de botones y frutos inmaduros en C. pentandra.

     

REVISION OF CHINESE SPECIES OF HEMIPTARSENUS WESTWOOD (HYMENOPTERA: EULOPHIDAE) *

Abstract This paper deals with Chinese species of Hemiptarsenus Westwood, 1833. Totally five species are found in China. Among them, H. unguicellus (Zetterstedt), H. ornatus (Nees) and H. varicornis (Gi‐rault) were previously recorded, H. zilahisebessi Erdös is newly recorded in China and H. strigiscuta sp. n. is described as new. A tentative key to known species is given, and other three external species, H. fulvicollis Westwood, H. wailesellae Nowicky and H. waterhousii Westwood, are included in the key for comparison. The type specimen is deposited in the Zoological Museum, Institute of Zoology, Chinese Academy of Sciences.     

Expression of TWEAK and its receptor Fn14 in human subcutaneous adipose tissue. Relationship with other inflammatory cytokines in obesity

TWEAK, a cytokine of the TNF family, has been found to be expressed under different inflammatory conditions but no data is available concerning the expression of this cytokine and its receptor (Fn14) in human obesity. In the present work we have evaluated the expression of many pro-inflammatory TNF system cytokines (TNF-alpha, TWEAK and their respective receptors, TNFR1, TNFR2 and Fn14) in human adipose tissue of 84 subjects some with different degree of obesity and type 2 diabetes, and its relation with inflammation by also measuring the expression of macrophage marker CD68. We detected expression of TWEAK and Fn14 in isolated mature adipocytes and in the stromovascular fraction. Additionally, we found that LPS upregulates the expression of both genes on THP-1 human monocytic cell line. TWEAK was expressed in adipose tissue of all studied subjects with no differences between obesity group, and was associated with Fn14 expression in morbid obese, mainly in women with type 2 diabetes. The data obtained here also showed that TNF-alpha and TNFR2 mRNAs were significantly more expressed in subcutaneous adipose tissue of subjects with morbid obesity compared to obese and non-obese subjects. In contrast, TNFR1 gene expression was negatively associated with BMI. Our results suggest that the expression of TNF-derived pro-inflammatory cytokines are increased in severe obesity, where macrophage infiltrate could modulate the inflammatory environment through activation of its receptors.     

LodB is required for the recombinant synthesis of the quinoprotein l-lysine-ε-oxidase from Marinomonas mediterranea

Marinomonas mediterranea is a marine gamma-proteobacterium that synthesizes LodA, a novel l-lysine-ε-oxidase (E.C. 1.4.3.20). This enzyme oxidizes L-lysine generating 2-aminoadipate 6-semialdehyde, ammonium, and hydrogen peroxide. Unlike other l-amino acid oxidases, LodA is not a flavoprotein but contains a quinone cofactor. LodA is encoded by an operon with two genes, lodA and lodB. In the native system, LodB is required for the synthesis of a functional LodA. In this study, we report the recombinant expression of LodA in Escherichia coli using vectors that allow its expression and accumulation in the cytoplasm. To reveal the l-lysine-ε-oxidase activity using the Amplex Red method for hydrogen peroxide detection, it is necessary to first remove the E. coli cytoplasmic catalases. The flavoprotein LodB is the only M. mediterranea protein required in the recombinant system for the generation of the cofactor of LodA. In the absence of LodB, LodA does not contain the quinone cofactor and remains in an inactive form. The results presented indicate that LodB participates in the posttranslational modification of LodA that generates the quinone cofactor.     

Brain proteomics identifies potential simvastatin targets in acute phase of stroke in a rat embolic model

Finding an efficient neuroprotectant is of urgent need in the field of stroke research. The goal of this study was to test the effect of acute simvastatin administration after stroke in a rat embolic model and to explore its mechanism of action through brain proteomics. To that end, male Wistar rats were subjected to a Middle Cerebral Arteria Occlusion and simvastatin (20 mg/kg s.c) (n = 11) or vehicle (n = 9) were administered 15 min after. To evaluate the neuroprotective mechanisms of simvastatin, brain homogenates after 48 h were analyzed by two‐dimensional fluorescence Difference in Gel Electrophoresis (DIGE) technology. We confirmed that simvastatin reduced the infarct volume and improved neurological impairment at 48 h after the stroke in this model. Considering our proteomics analysis, 66 spots, which revealed significant differences between groups, were analyzed by matrix‐assisted laser desorption/ionization‐time of flight mass spectrometry allowing the identification of 27 proteins. From these results, we suggest that simvastatin protective effect can be partly explained by the attenuation of the oxidative and stress response at blood–brain barrier level after cerebral ischemia. Interestingly, analyzing one of the proteins (HSP75) in plasma from stroke patients who had received simvastatin during the acute phase, we confirmed the results found in the pre‐clinical model.

     

Deposition of sediments during a flood event on seasonally flooded forests of the lower Orinoco River and two of its black-water tributaries, Venezuela

Deposition of suspended sediments andtheir associated nutrients were estimated during theflood event of 1995 in the seasonally flooded forestsof the Mapire and Caura Rivers, two black-watertributaries of lower Orinoco, and on two islands ofthis white-water river. The deposition spanned a widerange from 0.07 kg m^–2 in the depositional barforests of the Mapire River to 73.60 kg m^–2 onthe flooded forests of the Orinoco Island site calledJarizo. This variation is associated with the dynamicnature of sediment mobilization, transport anddeposition, as well as with the different geomorphicenvironments and erosion processes upstream from thestudy sites. The deposited sediment in all the studyareas was highly quartzitic with a relatively highcontent of kaolinite and goethite. Only in thesediment of the Orinoco Islands was mica (illite)identified in a relatively high proportion. Thesemineralogical results reflect the intense weatheringprocesses in the catchment areas of the study rivers.The chemical composition of the deposited sedimentsshowed a great variability among the different studyareas, which is in part related to the mineralcomposition of the sediments and their particle sizedistribution. The highest concentrations of K, Caand Mg were found on the clay sediments of the Orinocoagricultural island. The total amount of depositednutrients varied over a wide range, which isinfluenced by the amount of deposited sediments. Inthe Jarizo Island site of lower Orinoco were depositedthe largest amount of nutrients. In the floodedforests of the Mapire River, the nutrient contributionby the deposited sediments to the nutrient cycling isrelatively low in the depositional-bar forests andpractically nonexistent in the forests sites onterraces.     

Increased antifungal and chitinase specific activities of<Emphasis Type="Italic"> Trichoderma harzianum</Emphasis> CECT 2413 by addition of a cellulose binding domain

Trichoderma harzianum is a widely distributed soil fungus that antagonizes numerous fungal phytopathogens. The antagonism of T. harzianum usually correlates with the production of antifungal activities including the secretion of fungal cell walls that degrade enzymes such as chitinases. Chitinases Chit42 and Chit33 from T. harzianum CECT 2413, which lack a chitin-binding domain, are considered to play an important role in the biocontrol activity of this strain against plant pathogens. By adding a cellulose-binding domain (CBD) from cellobiohydrolase II of Trichoderma reesei to these enzymes, hybrid chitinases Chit33-CBD and Chit42-CBD with stronger chitin-binding capacity than the native chitinases have been engineered. Transformants that overexpressed the native chitinases displayed higher levels of chitinase specific activity and were more effective at inhibiting the growth of Rhizoctonia solani, Botrytis cinerea and Phytophthora citrophthora than the wild type. Transformants that overexpressed the chimeric chitinases possessed the highest specific chitinase and antifungal activities. The results confirm the importance of these endochitinases in the antagonistic activity of T. harzianum strains, and demonstrate the effectiveness of adding a CBD to increase hydrolytic activity towards insoluble substrates such as chitin-rich fungal cell walls.