Metazoan parasite communities of the Pacific red snapper, Lutjanus peru (Perciformes: Lutjanidae): interannual variations in parasite communities.

Metazoan parasite communities can experience temporal structural changes related to seasonal and/or local variations in several biotic and abiotic environmental factors. However, few studies have addressed this issue in tropical regions, where changes in water temperature are less extreme than in temperate regions, so the factors or processes that can generate variations in these parasite communities are as yet unclear. We quantified and analysed the parasite communities of 421 Lutjanus peru (Nichols & Murphy, 1922) collected from Acapulco Bay in Guerrero, Mexico, over a four-year period (August 2018 to April 2021), to identify any interannual variation due to local biotic and abiotic factors influenced by natural oceanographic phenomena, such as El Niño-Southern Oscillation, or La Niña. Twenty-five metazoan parasite taxa were recovered and identified: seven Digenea species; two Monogenea; one Cestoda; one Acanthocephala; four Nematoda; and ten of Crustacea (seven Copepoda and three Isopoda). The digeneans and copepods were the best represented parasite groups. The parasite communities were characterized by a high numerical dominance of helminth larvae. Species richness at the component community level (13 to 19 species) was similar to reported richness in other Lutjanus spp. The parasite communities of L. peru had a high variability in species composition, but low aggregate variability (e.g. species diversity), suggesting that structure of these communities may be quite stable over time. A clear interannual variation pattern was not observed, suggesting that parasite species of this host may respond differently to variations in environmental factors. Interannual variations were possibly caused by a combination of biotic (i.e. host feeding behaviour and body size) and local abiotic factors (influenced by climatic anomalies) which generated notable changes in the infection levels of several component species.

Antiproliferative activity of Haematoxylum brasiletto H. Karst.

BACKGROUND: Haematoxylum brasiletto is a tree that grows in Central America, commonly known as "Palo de Brasil," which is used in the traditional medicine for the treatment of cancer and gastric ulcers. OBJECTIVE: The aim of this study was to isolate the compounds responsible for antiproliferative activity of H. brasiletto. MATERIALS AND METHODS: A bioassay-guided fractionation of ethanol extract of H. brasiletto was performed using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide cell proliferation assay to measure the antiproliferative activity on six human cancer cell lines (A549, LS180, HeLa, SiHa, MDA-MB-231, and NCI-H1299) and one human noncancer cell line (ARPE-19). The ethanol extract was partitioned with hexane, dichloromethane, and ethyl acetate. The active dichloromethane fraction was fractioned by silica-column chromatography, and active subfractions were separated using preparative-thin layer chromatography. The chemical structure of an isolated compound was elucidated with different chemical and spectroscopic methods. RESULTS: The flavonoid brazilin (1) was isolated from the heartwood of H. brasiletto. The measurement of antiproliferative activity showed that brazilin can inhibit the growth of SiHa, MDA-MB-231, A549, and NCI-H1299 cell lines by 50% at doses of 44.3, 48.7, 45.4, and 48.7 µM, respectively. Furthermore, the flavonoid showed a high antiproliferative activity on LS 180 and HeLa with IC50 values of 62.2 and 71.9 µM, respectively. Brazilin also exhibited a high antiproliferative activity on the human noncancer cell line ARPE-19 with an IC50 value of 37.9 µM. CONCLUSIONS: Brazilin: (6aS, 11bR)-7,11b-Dihidro-6H-indeno[2,1-c] cromeno-3,6a, 9,10-tetrol was isolated; this compound demonstrated antiproliferative activity against several human cancer cell lines. This work demonstrated that brazilin, a flavonoid isolated and characterized of H. brasiletto, has antiproliferative activity against cancer cell lines. SUMMARY: The flavonoid brazilin was isolated from the heartwood of H. brasilettoBrazilin is able to inhibit the growth of SiHa, MDA-MB-231, A549 and NCI- H1299 cancerous cell linesBrazilin exhibited a moderate antiproliferative activity on the human non-cancer cell line ARPE-19Brazilin demonstrated to have antiproliferative activity against human cancer cell lines and could be a potential source of anticancer agents. Abbreviations used: MTT: [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium]; FBS: Fetal bovine serum; TLC: Thin layer chromatography.

Early postnatal ethanol intubation blunts GABA(A) receptor up-regulation and modifies 3alpha-hydroxy-5alpha-pregnan-20-one sensitivity in rat MS/DB neurons.

Previously we found postnatal binge-like ethanol exposure using an artificial-rearing method in the rat delayed developmental up-regulation of GABA(A) receptors (GABA(A)Rs) in both medial septum/diagonal band (MS/DB) and cerebellar Purkinje neurons. In the present study, the impact of ethanol on developing GABA(A)Rs in MS/DB neurons was further tested under conditions not requiring anesthesia or maternal deprivation. Nursing rat pups received ethanol (4.5-5.25 g/kg/day) on postnatal days (PD) 4-9, which was administrated manually by oral intragastric intubation. This treatment caused dose-dependent blunting of peak GABA(A) receptor whole cell currents in acutely dissociated MS/DB cells on PD 12-15. The threshold with oral intubation was slightly higher than previously observed for artificial-rearing (4.9 vs. 4.5 g/kg/day). The previously observed reduced sensitivity of GABA(A)Rs to Zn(2+)-inhibition after ethanol was not found with the intubation model. In studies only carried out using the intubation method, 3alpha-hydroxy-5alpha-pregnan-20-one (3alpha-OH-DHP) caused an allosteric concentration-dependent potentiation of currents activated by non-saturated concentrations of GABA. A bicuculline sensitive direct activation of GABA(A)Rs also occurred with higher concentrations of 3alpha-OH-DHP alone. Ethanol intubation up-regulated allosteric neurosteroid potentiation with low concentrations of GABA, but did not change direct agonist actions of 3alpha-OH-DHP. Finally, 3alpha-OH-DHP did not prime ethanol insensitive GABA(A)Rs to become sensitivity to acute ethanol potentiation. These results indicate ethanol consistently blunts postnatal GABA(A) receptor up-regulation across early postnatal binge-type ethanol exposure models and may increase positive modulation of GABA(A) receptors by endogenous neurosteroids.

Pathogenicity bioassays of Hirsutella thompsonii fisher and H. nodulosa petch strains facing up to Tetranychus urticae Koch.

The objective of this work was to determine, trough bioassays, the most virulent strains of Hirsutella to be used as a control alternative in a pest intregrated wield program are those which are most pathogenic to CL50 just as H. nodulosa (HnC83) with 5 x 10(5) conidia/ml, and H. thompsonii (HtMOR and HtM5) with 1 x 10(6) and 1.1 x 10(6) conidia/ml respectively. The strain we recommend to attack Tetranychus urticae is H. thompsonii HtMOR. Although it did not seem to be the most aggressive to CL50, it was the strain that required the lowest concentration (0.0014%/1.5 x 10(10)) to kill 95% of the population evaluated. At the same time, the strain that we considered as having a lower virulence was HtM2 (4 x 10(6) c/ml) and the lowest virulence was detected both in HtC59 and HtC77 (1 x 10(10) c/ml).

[Sporulation of the entomopathogenic fungi Hirsutella thompsonii Fisher and H. nodulosa petch in mixed culture]. / Esporulación de los hongos entomopatógenos Hirsutella thompsonii Fisher y H. nodulosa petch en cultivo mixto.

A large-scale method for producing fungal pathogens for mites, Hirsutella thompsonii and H. nodulosa in two phase culture (liquid and solid), was developed to induce conidiogenesis. The vegetative growth that was obtained in the liquid media of soy meal with shaking, from an inoculum 0.5 g wet weight equivalent to 0.1 g of dry weight, was inoculated on eight solid supports. Generally for most of the strains, the three supports yielding greater conidiogenesis were rice, barley and bran, excluding the strains whose greater sporulation is achieved in rice, oats and sorghum, sorghum and oats as compared to barley and bran, respectively. Maximum production of conidia was obtained with HtM2, HtM4481 and HtC59 strains of H. thompsonii, which reached on solid support 334.75, 269.68 and 137.12 x 10(7) conidia/g, respectively.