Variation of the essential oil content and composition in leaves from cultivated plants of Hypericum androsaemum L

The amount and composition of the essential oil from leaves of Hypericum androsaemum L. cultivated in Arouca (Portugal) were determined in six samples harvested during 1 year at intervals of 2 months. The seasonally dependent essential oil content ranged from 0.7 mg/g biomass dry weight in September to 3.4 mg/g in February. The oil contained more than 80 compounds, 70 of which (constituting 88-93% of the total oil) were identified by GC and GC-MS. An approximation of the absolute quantification of each compound and compound class was performed using a GC method with an internal standard. The relative and the absolute content of each compound and compound class changed during the year. At the end of the winter and in the spring, the essential oil was dominated by sesquiterpene hydrocarbons and accumulated a high number of intermediate to long chain n-alkanes and 1-alkenes. In September, the essential oil contained the lowest levels of sesquiterpene hydrocarbons (43%) and the highest levels of 1-octene and 2-hexenal (38%). In February, the essential oil had the highest level of sesquiterpene hydrocarbons (73%) and the highest diversity of intermediate to long chain n-alkanes and 1-alkenes.     

Quantitative and qualitative analysis of the effectiveness of a mechanical method for the isolation of preantral follicles from ovine ovaries

The preantral follicles are the major source of oocytes and its utilization has been investigated as an important tool to store large numbers of female gametes for further utilization in reproductive programs. The aim of the present study was to perform quantitative and qualitative analyses of the efficacy of a mechanical method for isolating of preantral follicles from the ovaries of fetuses and from nonpregnant and pregnant ewes, using as reference the population of preantral follicles in situ. In the isolation method the ovaries were cut into fragments in the tissue chopper. Then, the suspension was filtered through nylon mesh filters. The number of isolated follicles per ovary was 1655, 4735 and 4770, respectively, for the fetus, nonpregnant ewe and pregnant ewe. The number of in situ preantral follicles per ovary was 32961, 16627 and 17794, respectively, for the fetus, nonpregnant ewe and pregnant ewe. The follicle recovery rate (number of isolated preantral follicles/number of in situ preantral follicles x 100) was higher in adult ewes (26 and 28%, respectively, for nonpregnant and pregnant ewes) than in fetuses (5%). Histological analysis showed that very few preantral follicles (less than 0.26% in situ and 0.46% after the isolation procedure) were degenerated. In conclusion, this study showed that a mechanical method could be used effectively to isolate a large number of intact ovine preantral follicles. In the future, with improvements in culture systems, the isolation of a great number of oocytes enclosed in preantral follicles will make a valuable contribution to the rare breeds and endangered species, agricultural efficiency and basic research in folliculogenesis.     

Spawning Sounds of the Male Haddock, Melanogrammus aeglefinus

The codfish family, Gadidae, contains many vocal species. The sounds produced are species-characteristic and relatively simple. Unusually within this family, the haddock Melanogrammus aeglefinus, produces a range of sounds in different contexts. Both male and female haddock produce short sequences of repeated knocks during agonistic encounters. During the spawning season, however, male fish produce sounds which vary in their characteristics as courtship proceeds. The repertoire of the male fish consists of a graded series of sounds ranging from a short series of slowly repeated knocks to long sounds of rapidly repeated knocks. The fastest sounds are heard as a continuous humming. Different behavioural acts leading up to the mating embrace are associated with particular sounds, the sounds becoming longer and faster as the level of arousal of the male increases. It is suggested that the sounds serve to bring male and female fish together in the same part of the ocean, and that the sounds also play a role in synchronising the reproductive behaviour of the male and female.     

Role for Sit4p-dependent mitochondrial dysfunction in mediating the shortened chronological lifespan and oxidative stress sensitivity of Isc1p-deficient cells

Saccharomyces cerevisiae cells lacking Isc1p, an orthologue of mammalian neutral sphingomyelinase 2, display a shortened lifespan and an increased sensitivity to oxidative stress. A lipidomic analysis revealed specific changes in sphingolipids that accompanied the premature ageing of Isc1p-deficient cells under severe calorie restriction conditions, including a decrease of dihydrosphingosine levels and an increase of dihydro-C(26) -ceramide and phyto-C(26) -ceramide levels, the latter raising the possibility of activation of ceramide-dependent protein phosphatases. Consequently, deletion of the SIT4 gene, which encodes for the catalytic subunit of type 2A ceramide-activated protein phosphatase in yeast, abolished the premature ageing and hydrogen peroxide sensitivity of isc1Δ cells. SIT4 deletion also abolished the respiratory defects and catalase A deficiency exhibited by isc1Δ mutants. These results are consistent with catabolic derepression associated with the loss of Sit4p. The overall results show that Isc1p is an upstream regulator of Sit4p and implicate Sit4p activation in mitochondrial dysfunction leading to the shortened chronological lifespan and oxidative stress sensitivity of isc1Δ mutants.     

Thrombin allosteric modulation revisited: a molecular dynamics study

The regulatory properties of thrombin are derived predominantly from its capacity to produce different functional conformations. Functional studies have revealed that two antagonistic thrombin conformations exist in equilibrium: the fast (procoagulant) and slow (anticoagulant) forms. The mechanisms whereby thrombin activity is regulated by the binding of different effectors remain among the most enigmatic and controversial subjects in the field of protein function. In order to obtain more detailed information on the dynamic events originating from the interaction with the Na⁺ effector and ligand binding at the active site and anion binding exosite 1 (ABE1), we carried out molecular dynamics simulations of thrombin in different bound states. The results indicated that Na⁺ release results in a more closed conformation of thrombin, which can be compared to the slow form. The conformational changes induced by displacement of the sodium ion from the Na-binding site include: (1) distortion of the 220- and 186-loops that constitute the Na-binding site; (2) folding back of the Trp148 loop towards the body of the protein, (3) a 180° rotation of the Asp189 side-chain, and (4) projection of the Trp60D loop toward the solvent accompanied by the rearrangement of the Trp215 side chain toward the 95–100 loop. Our findings correlate well with the known structural and recognition properties of the slow and fast forms of thrombin, and are in accordance with the hypothesis that there is communication between the diverse functional domains of thrombin. The theoretical models generated from our MD simulations complement and advance the structural information currently available, leading to a more detailed understanding of thrombin structure and function.     

Diterpene from marine brown alga <Emphasis Type="Italic">Dictyota friabilis</Emphasis> as a potential microbicide against HIV-1 in tissue explants

Due to the great genetic diversity of HIV, producing an effective vaccine is extremely difficult. The combined antiretroviral therapy, although not leading to a cure, is capable of preventing opportunistic infections, since it greatly reduces HIV viral load in the blood. Considering a large number of HIV infections occur through sexual intercourse, the use of topical microbicides could be very useful tools to reduce infection rates. Studies by our group showed that the dolabelladienetriol, isolated from the brown seaweed Dictyota friabilis, had a clear effect on replication by inhibiting HIV-1 replication in cell culture. In this study, we have demonstrated that pretreatment with this compound for 2 h or 1 to 5 days, showed an inhibitory effect ranging from 60 to 90 % in peripheral blood cells (PBMC) and macrophages infected with HIV-1, respectively. Following the studies, we found that the dolabelladienetriol after being subjected to the experimental model of ex vivo cervical mucosa did not show toxicities in concentrations that were used for the experiments. Subsequently, we evaluate the protective effect of dolabelladienetriol in explant model in uterine cervix, showing a curve of dose-dependent inhibition in treatment with different concentrations of the compound in the presence of HIV-1 with 20 to 99 % in concentrations of 0.15 and 14.4 μM, respectively. These studies demonstrate the important effect of dolabelladienetriol that can be recognized as a microbicide.     

Host-use pattern of the shrimp <Emphasis Type="Italic">Periclimenes paivai</Emphasis> on the scyphozoan jellyfish <Emphasis Type="Italic">Lychnorhiza lucerna</Emphasis>: probing for territoriality and inferring its mating system

In symbiotic crustaceans, host-use patterns vary broadly. Some species inhabit host individuals solitarily, other species live in heterosexual pairs, and even other species live in aggregations. This disparity in host-use patterns coupled with considerable differences in host ecology provide opportunities to explore how environmental conditions affect animal behavior. In this study, we explored whether or not symbiotic crustaceans inhabiting relatively large and structurally complex host species live in aggregations. We expected Periclimenes paivai, a small caridean shrimp that lives among the tentacles of the large and morphologically complex scyphozoan jellyfish Lychnorhiza lucerna, to live in groups given that the host traits above constraint host-monopolization behaviors by symbiotic crustaceans. We described the population distribution of P. paivai during a bloom of L. lucerna near the mouth of the Paraíba River estuary in Paraíba, Brazil. The population distribution of P. paivai did not differ statistically from a random Poisson distribution. Male shrimps were most often found dwelling on the surface of L. lucerna individuals as small groups (2–4 individuals), in agreement with expectations. Periclimenes paivai is a sexually dimorphic species with males attaining smaller average body sizes than females and exhibiting no elaborated weaponry (claws). Females, but not males, experience positive allometry in cheliped size and were found living solitarily in small but not large host individuals. The above suggest that females might be territorial or that they might be competing for resources (i.e., food) likely expected to impact their reproductive output. Our results agree, but only partially, with the idea that large and morphologically complex host species should harbor non-territorial gregarious symbiotic crustaceans. Symbiotic crustaceans represent excellent models to improve our understanding about the conditions driving the social behavior of marine organisms.     

A new species of Myrcia (Myrteae, Myrtaceae) from the Atlantic Forest of southern Bahia, Brazil

Myrcia thomasii, a new species from the Atlantic Forest of southern Bahia, is described and illustrated. The new species is similar to M. micropetala, but differs in having the inflorescence and basal bracts puberulent, lanceolate bracts at the base of flowers, longer calyx lobes and petals, and a 3-locular ovary.     

On ecology,life history and survival strategies of a wing‐dimorphic ground beetle (col.: Carabidae: Odacanthini: Colliuris) inhabiting central Amazonian inundation forests

The discovery of a lowland Amazonian wing‐dimorphic carabid species, Colliuris batesi Chaudoir, prompted a complete study of its biology and behaviour over a period of more than 4 years. Studies were made on development, fecundity, gonad development, life span and habitat shifts. Survival strategies and possible adaptations are examined with respect to seasonal flooding of their habitat. It is proposed that evolution of brachyptery in this species is rather recent in origin because macropterous specimens are widespread across the upper Amazon Basin, and because the only body change associated with short wings has been narrowing of the humeri.