Culture of Poecilia reticulata (Pisces: Poecilidae) in tropical water bodies, Veracruz, México

Poecilia reticulata, also known as guppy, is the most popular fish in the aquarium environment. Guppys are viviparous fish with high tolerance to extreme temperatures. The development of the offspring takes between 25 and 30 days. We developed a technology for raising guppys, which outlines infrastructure and devices for reproduction, nursery, feeding, and commercialization, evaluating the financial and technical feasibility of this technology in a case study. The complete reproductive cycle occured in floating cages with 1 mm mesh and the method was tested in a tropical lagoon in Mexico. Water quality was monitored throughout the study period (temperature, dissolved oxygen and pH levels). A marketing survey was carried out at all existing aquarium shops in Veracruz City. Data collected depict quantities demanded and offered for each species by season, place of origin, and resistance to handling. The hydrobiological characteristics were: average temperature 31.4 degrees C, dissolved oxygen 4.5 mgl(-1), and pH level 6.8. With these values we built a production function, and used it to evaluate profitability. We estimate a benefit/cost ratio of 1.16, with a net annual income of US$257.67. The system may provide two permanent jobs.     

Effects of folic acid and amino acids supplementation on zinc intestinal absorption in the progeny of ethanol-treated rats

This study was designed to examine the effects of supplementation with folic acid and amino acids in dams that consumed ethanol during gestation and lactation to see whether there is an improvement in the intestinal absorption of zinc in pup rats on the 21st day after birth. The rats were randomized into two groups: Ethanol-rats (EG) were administered ethanol during the pregnancy and lactation periods; the ethanol-folic acid group (EFG) received a folic acid and amino acid supplement concomitantly with ethanol administration during pregnancy and lactation. The dams were mated to obtain the first offspring. Two sets of experiments were performed on the offspring at 21 days after birth. In general, in the first set, jejunal zinc absorption in the offspring of EG and EFG groups showed a gradual increase along with increased perfusion time at all assayed concentrations. Jejunal zinc absorption expressed as nmol/intestinal surface was higher in the ethanol-folic acid group than in ethanol animals at all assayed concentrations except at 25 microM concentration. In the second set of experiments, distal ileum zinc absorption in the offspring of ethanolfolic acid dams showed a significant increase at all concentrations tested. These results indicate that supplementation of folic acid and amino acids to dams that consume ethanol during gestation and lactation increase serum and milk zinc levels, although the zinc ingestion is lower. In pups of the supplemented dams, the jejunal and ileal absorption of zinc increased; as a consequence, the serum zinc levels increased. The activity of alcohol dehydrogenase, a metaloenzyme dependent on zinc levels, also increased.     

Changes in race-specific virulence in Pseudomonas syringae pv. phaseolicola are associated with a chimeric transposable element and rare deletion events in a plasmid-borne pathogenicity island

Virulence for bean and soybean is determined by effector genes in a plasmid-borne pathogenicity island (PAI) in race 7 strain 1449B of Pseudomonas syringae pv. phaseolicola. One of the effector genes, avrPphF, confers either pathogenicity, virulence, or avirulence depending on the plant host and is absent from races 2, 3, 4, 6, and 8 of this pathogen. Analysis of cosmid clones and comparison of DNA sequences showed that the absence of avrPphF from strain 1448A is due to deletion of a continuous 9.5-kb fragment. The remainder of the PAI is well conserved in strains 1448A and 1449B. The left junction of the deleted region consists of a chimeric transposable element generated from the fusion of homologs of IS1492 from Pseudomonas putida and IS1090 from Ralstonia eutropha. The borders of the deletion were conserved in 66 P. syringae pv. phaseolicola strains isolated in different countries and representing the five races lacking avrPphF. However, six strains isolated in Spain had a 10.5-kb deletion that extended 1 kb further from the right junction. The perfect conservation of the 28-nucleotide right repeat of the IS1090 homolog in the two deletion types and in the other 47 insertions of the IS1090 homolog in the 1448A genome strongly suggests that the avrPphF deletions were mediated by the activity of the chimeric mobile element. Our data strongly support a clonal origin for the races of P. syringae pv. phaseolicola lacking avrPphF.     

Synthesis and evaluation of the antiproliferative activity of novel thiazoloquinazolinone kinases inhibitors

The microwave-assisted synthesis of a family of 2,8-substituted thiazoloquinazolinones is described. The preliminary evaluation of the antiproliferative activity and the capacity of these molecules to inhibit CDKs and GSK-3 are reported. A lead compound was identified, constituting a scaffold from which more potent inhibitors could be designed.     

Effects of Changing Rainfall on the Limnology of a Mediterranean,Flowthrough‐Seepage Chain of Lakes

Relationships between groundwater and lake ecology are often overlooked, but they may be strong, particularly in seepage lakes. As a result, the nature and degree of groundwater effects on lakes are usually neglected. In this study interactions among rainfall, groundwater and surface water and their limnological effects were traced seasonally for two years of changing rainfall in a Spanish flowthrough, seepage lake complex. Cumulative rainfall dictated recharge of groundwater with delays of nine months. Groundwater discharge, in turn, increased surface discharge downstream. Mediated by the geographical setting of lakes, both fluxes impinged on lake water renewal time, but effects of the latter on limnological variables were much stronger at the district scale than at the single lake scale. These water‐renewal effects included the following: decreasing salinity, total phosphorus concentration and phytoplankton biomass and increasing water transparency and total nitrogen concentration as water renewal shortened, the nitrogen effect arising because of nitrate‐rich water entering the lakes as groundwater levels rose. This complex response of a Mediterranean lake district to water availability may also be expected in cold temperate lakes as climate change effects become stronger. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Actual and potential dark respiration rates and different electron transport pathways in freshwater aquatic plants

The rates of respiratory O₂ uptake have been studied in leaves, stems and whole shoots of several freshwater plants: 6 angiosperms, 2 bryophytes and one alga. For angiosperm leaves, rates varied widely with species (30–142 μmol O₂ (gDW)⁻¹ h⁻¹), were correlated with chlorophyll content and were higher than those of the stems (13–71 μmol O₂ (gDQ)⁻¹ h⁻¹). The rates for the shoots of bryophytes (53–66 μmol O₂ (gDW)⁻¹ h⁻¹) and for the alga Cladophora glomerata (L.) Kütz. (96 μmol O₂ (gDW)⁻¹ h⁻¹) were slightly higher than those of most angiosperm stems, but lower than those for most leaves.

These plants had a significant cyanide-resistant respiration, suggesting the existence of an alternative pathway to the “classic” cytochrome system. This pathway was found to be active in all the species studied, as judged by responses to a specific inhibitor, SHAM (salicylhydroxamic acid). Measurement of electron-transport system (ETS) activity showed that there is a large electron-transport capacity which is not normally used by respiration in vivo.