Activity of Matricaria chamomilla essential oil against anisakiasis

The increase in diagnosed cases of anisakiasis and the virtual absence of effective treatments have prompted the search for new active compounds against Anisakis L(3) larvae. The biocidal efficacy against different pathogens shown by various essential oils (EO) led us to study the Matricaria chamomilla EO and two of its main components (chamazulene and α-bisabolol) against the L(3) larvae of Anisakis type I. The activity of M. chamomilla EO, chamazulene and α-bisabolol was established by in vitro and in vivo experiments. The EO (125μg/ml) caused the death of all nematodes, which showed cuticle changes and intestinal wall rupture. In the in vivo assays, only 2.2%±1.8 of infected rats treated with M. chamomilla EO showed gastric wall lesions in comparison to 93.3%±3.9 of control. Chamazulene was ineffective, while α-bisabolol showed a high activity to that of the EO in vitro tests but proved less active in vivo. These findings suggest that the larvicidal activity may result from the synergistic action of different compounds of M. chamomilla EO. Neither of the tested products induces irritative damage in the intestinal tissues. In conclusion, M. chamomilla EO is a good candidate for further investigation as a biocidal agent against Anisakis type I.     

FAF1, a gene that is disrupted in cleft palate and has conserved function in zebrafish

Cranial neural crest (CNC) is a multipotent migratory cell population that gives rise to most of the craniofacial bones. An intricate network mediates CNC formation, epithelial-mesenchymal transition, migration along distinct paths, and differentiation. Errors in these processes lead to craniofacial abnormalities, including cleft lip and palate. Clefts are the most common congenital craniofacial defects. Patients have complications with feeding, speech, hearing, and dental and psychological development. Affected by both genetic predisposition and environmental factors, the complex etiology of clefts remains largely unknown. Here we show that Fas-associated factor-1 (FAF1) is disrupted and that its expression is decreased in a Pierre Robin family with an inherited translocation. Furthermore, the locus is strongly associated with cleft palate and shows an increased relative risk. Expression studies show that faf1 is highly expressed in zebrafish cartilages during embryogenesis. Knockdown of zebrafish faf1 leads to pharyngeal cartilage defects and jaw abnormality as a result of a failure of CNC to differentiate into and express cartilage-specific markers, such as sox9a and col2a1. Administration of faf1 mRNA rescues this phenotype. Our findings therefore identify FAF1 as a regulator of CNC differentiation and show that it predisposes humans to cleft palate and is necessary for lower jaw development in zebrafish.     

Ichthyoplankton distribution as an indicator of hydrodynamic conditions of a lagoon system in the Mexican Caribbean

The salt-water intrusion into a lagoon system of the Sian Ka’anBiosphere Reserve was assessed during 1 year and related tothe marine component of the larval fish assemblage. This systemis environmentally complex because of the penetration of marinewater, and the discharge of surface and subterranean water.Biological samples were collected during four field expeditionsfrom October 1996 to August 1997. Surface circular tows with500-µm-mesh conical plankton nets with a flowmeter weremade during the day. Position, depth, temperature and salinitywere recorded at each sampling station. All fish larvae wereremoved from the samples and identified to the lowest possibletaxon. Ichthyoplankton abundance was normalized to 100 m³ ofwater. The distribution patterns of the carangiid Oligoplitessaurus, the herring Opisthonema oglinum, the dragonet Diplogrammuspauciradiatus and members of the Tetraodontidae were relatedto the wind-driven circulation pattern of the lagoons obtainedusing a numerical model. The analysis of the distribution ofichthyoplankton showed that these species are good indicatorsof the spatial salinity variations controlled by the hydrodynamiccharacteristics of the system. The spatial use of these estuariesas a habitat for fish larvae is therefore strongly influencedby salinity distribution, itself modulated by annual variationof wind stress.     

Molecular cloning of Renibacterium salmoninarum DNA fragments

A Renibacterium salmoninarum enriched recombinant DNA library was constructed to isolate DNA fragments which could be used as probes to detect gene sequences specific for the causative agent of bacterial kidney disease in salmonid fish. One fragment of 149 base pairs was isolated and its specificity and sequence determined. This probe may prove useful in the design of diagnostic tests for the disease in asymptomatic fish and ova.     

Assessing transpiration in the tussock grass Stipa tenacissima L.: the crucial role of the interplay between morphology and physiology

Plant transpiration has a key role on both plant performance and ecosystem functioning in arid zones, but realistic estimates at appropriate spatial-temporal scales are scarce. Leaf and tiller morphology and crown architecture were studied together with leaf physiology and whole plant water balance in four individual plants of Stipa tenacissima of different sizes to determine the relative influence of processes taking place at different spatial and temporal scales on whole plant transpiration. Transpiration was estimated in potted plants by leaf-level gas exchange techniques (infrared gas analyzer and porometer), by sap flow measurements, and by integrating leaf physiology and crown architecture with the 3-D computer model Yplant. Daily transpiration of each individual plant was monitored using a gravimetric method, which rendered the reference values. Leaves on each individual plant significantly varied in their physiological status. Young and green parts of the leaves showed five times higher chlorophyll concentration and greater photosynthetic capacity than the senescent parts of the foliage. Instantaneous leaf-level transpiration measurements should not be used to estimate plant transpiration, owing to the fact that extrapolations overestimated individual transpiration by more than 100%. Considering leaf age effects and scaling the estimates according to the relative amount of each foliage category reduced this difference to 46% though it was still significantly higher than gravimetric measurements. Sap flow calculations also overestimated tussock transpiration. However, 3-D reconstruction of plants with Yplant and transpiration estimates, considering both the physiological status and the daily pattern of radiation experienced by each individual leaf section within the crown, matched the gravimetric measurements (differences were only 4.4%). The complex interplay of leaf physiology and crown structure must be taken into account in scaling up plant transpiration from instantaneous, leaf-level measurements, and our study indicates that transpiration of complex crowns is easily overestimated.     

The effect of guanosine nucleotides on the multiple forms of protein synthesis elongation factor 1 from wheat embryos

At least two species of elongation factor 1 from wheat embryo have been detected by sucrose gradient analysis and Sephadex gel filtration. The heavy species (EF1_h) which has a molecular weight of 200,000 can be converted into the light species (EF1_l) with a molecular weight of approximately 50,000 by addition of GTP or GDP. The conversion of EF1_h to EF1_l is more rapid in the presence of GDP than in the presence of GTP. Aminoacyl-tRNA which reacts preferentially with EF1_l favors the conversion of EF1_h to EF1_l with GTP. Both GTP and GDP promote inactivation of EF1_h, but the addition of aminoacyl-tRNA counteracts the effect of the guanosine triphosphate. These reactions are discussed with respect to the function of the various forms of EF1 in aminoacyl-tRNA binding to ribosomes.     

Segregation of elongation potential inEscherichia coli mediated by thewee genetic system

Under normal conditions, the two cells within a pair ofEscherichia coli siblings elongate at a similar rate. Genetic impairment of thewee genetic system leads to significant variations in the rate of elongation of each cell within a given pair of siblings. This result is in accordance with previous reports that showed the need of active cell division for expression of the Wee phenotype. The genetic location of one element of the system,weeA, has been determined to be at min 67 of theE. coli map; this does not coincide with the previously reported genetic location. The inability to reproduce the Wee phenotype in a wild-type background by transduction ofweeA suggests that more genetic elements should participate in the segregation of elongation zones at cell division.     

dATP accumulation and ATP depletion in platelets in adenosine deaminase deficiency: Significance for the immune response?

High levels of dATP and dADP, accompanied by ATP depletion, were found in the platelets of two ADA-deficient children with severe combined immunodeficiency (SCID). In vitro studies demonstrated that even normal platelets had the ability to make dATP from deoxyadenosine (dAR) under physiological conditions. This capability was greatly enhanced by conditions simulating ADA deficiency. These results question whether the platelet has a specific role in the normal immune response.