Evaluation of cDNA Libraries from Different Developmental Stages of Schistosoma mansoni for Production of Expressed Sequence Tags (ESTs)

A comparative study of the gene expression profile in differentdevelopmental stages of Schistosoma mansoni has been initiatedbased on the expressed sequence tag(EST) approach. A total of1401 ESTs were generated from seven different cDNA librariesconstructed from four distinct stages of the parasite life cycle.The libraries were first evaluated for their quality for a large-scalecDNA sequencing program. Most of them were shown to have lessthan 20% useless clones and more than 50% new genes. The redundancyof each library was also analyzed, showing that one adult wormcDNA library was composed of a small number of highly frequentgenes. When comparing ESTs from distinct libraries, we coulddetect that most genes were present only in a single library,but others were expressed in more than one developmental stageand may represent housekeeping genes in the parasite. When consideringonly once the genes present in more than one library, a totalof 466 unique genes were obtained, corresponding to 427 newS. mansoni genes. From the total of unique genes, 20.2% wereidentified based on homology with genes from other organisms,8.3% matched S. mansoni characterized genes and 71.5% representunknown genes.     

GIANT KELP (MACROCYSTIS PYRIFERA, PHAEOPHYCEAE) RECRUITMENT NEAR ITS SOUTHERN LIMIT IN BAJA CALIFORNIA AFTER MASS DISAPPEARANCE DURING ENSO 1997–1998

During the ENSO event of 1997–1998, density and population structure were evaluated in a Macrocystis pyrifera forest located in Bahía Tortugas, Baja California, Mexico, near the southern limit of the species' distribution in the Northern Hemisphere. Observations in Bahía Tortugas were made quarterly from January 1997 to September 1998 using SCUBA diving surveys. No macroscopic plants were found in the Bahía Tortugas area from October 1997 to April 1998, a local absence of at least 7 months. Aerial surveys further suggest regional disappearance along most of the Baja California coast during the event. Unexpectedly, plants were found in Bahía Tortugas again in July 1998, in spite of the widespread disappearance of the species less than a year earlier. Long-distance spore dispersal was an unlikely cause of the recruitment because: 1) the nearest spore source was more than 100 km away; 2) recruitment appeared to be simultaneous at many sites and occurred rapidly after the cessation of the ENSO event; and 3) the recruits occurred in the same areas as before disappearance. We suggest that a microscopic stage that was not visible during dive surveys survived the stressful conditions of ENSO and caused the recruitment event, supporting the hypothesis that a bank of microscopic forms can survive conditions stressful to macroscopic algae.     

Biology of Anagrus atomus (Hymenoptera: Mymaridae), an egg parasitoid of the grape leafhopper Arboridia kermanshah (Homoptera: Cicadellidae)

Biology, morphology and oviposition behavior of Anagrus atomus (Linnaeus), an egg parasitoid of the grape leafhopper Arboridia kermanshah Dlabola in Isfahan, Iran, were investigated. Adults were smaller than those so far reported from other regions. Females continuously drummed on plant surfaces with their antennae to search for host eggs. Parasitoid eggs hatched 2–3 days after oviposition, and A. atomus had two larval instars. First instar larvae were sacciform and immobile. Second instar larvae appeared 4 days after oviposition and were very active, and doubled their body length. The prepupal and pupal stages lasted for 1 and 5–6 days, respectively. Adult emergence began 16 days after oviposition, and peaked on day 17.     

Effects of fish farm effluents on egg-to-fry development and survival of brown trout in artificial redds

Egg-to-fry development and survival of brown trout Salmo trutta were compared in two rivers of the Pyrenean piedmont, the Nive d'Arnéguy, with few human activities, and the Nive des Aldudes, with many anthropogenic activities including 11 fish farms and two sewage treatment plants (STPs). Survival was estimated between spawning (early December) and emergence time (early March) by means of capsules, 7 cm³ in volume, filled with green eggs then inserted into the gravel of artificial redds at spawning sites. In the Nive des Aldudes, three sets of conditions were studied: a fish farm near the springs, a fish farm and an STP in a village, and a series of fish farms and an STP in a village. In each situation, two artificial redds were created upstream and two others downstream from the fish farms. In the Nive d'Arnéguy, four sites were equipped: each of the two downstream sites with two artificial redds, and the two upstream sites with one redd. Substratum characteristics (proportion of fine particles) and the quality of surface and interstitial water (oxygen content, ammonia and nitrite nitrogen) were periodically measured. There was no redd substratum difference between sites upstream and downstream of fish farms. Survival to fry emergence was higher in the Nive d'Arnéguy (63·5%) than in the Nive des Aldudes (47·7%). In this latter river, the nitrogen released from the STPs was 0·5% that from fish farms. Fish farming impaired survival close to fish farm effluents (31·6%), as compared to survival upstream (63·6%), and induced a development delay during the yolk-sac fry stage. These differences were mainly linked to a drop in the dissolved oxygen content in interstitial water induced by the nitrogen flow in surface and interstitial waters.     

Surface ultrastructure of Metagonimus miyatai metacercariae and adults

A scanning electron microscopic study was performed to observe surface ultrastructures of excysted metacercariae and adults of Metagonimus miyatai. Metacercariae were collected from the scale of the pale chub (Zacco platypus), and adult flukes were harvested 1-4 weeks after infection to rats. In excysted metacercariae, the oral sucker was devoid of tegumental spines and had type I and type II sensory papillae. Anteriorly to the ventral sucker, spines were dense and digitated into 5-7 points, whereas near the posterior end of the body spines were sparse and digitated into 2-3 points. In one-week adults, 7 type II sensory papillae were arranged around the lip of the oral sucker, and at inner side of the lip one pair of small and two pairs of large type 1 sensory papillae were seen on each side. The distribution of tegumental spines was similar to that of metacercariae, but they were more differentiated with 9-11 pointed tips. In two- to four-week old adults, the surface ultrastructure was nearly the same as in one-week old adults, however, sperms were frequently seen entering into the Laurer''s canal. Conclusively, the surface ultrastructure of M. miyatai was generally similar to that of M. yokogawai, however, differentiation of tegumental spines and distribution of sensory papillae around the oral sucker were different between the two species, which may be of taxonomic significance.     

Animal behaviour shapes the ecological effects of ocean acidification and warming: moving from individual to community‐level responses

Biological communities are shaped by complex interactions between organisms and their environment as well as interactions with other species. Humans are rapidly changing the marine environment through increasing greenhouse gas emissions, resulting in ocean warming and acidification. The first response by animals to environmental change is predominantly through modification of their behaviour, which in turn affects species interactions and ecological processes. Yet, many climate change studies ignore animal behaviour. Furthermore, our current knowledge of how global change alters animal behaviour is mostly restricted to single species, life phases and stressors, leading to an incomplete view of how coinciding climate stressors can affect the ecological interactions that structure biological communities. Here, we first review studies on the effects of warming and acidification on the behaviour of marine animals. We demonstrate how pervasive the effects of global change are on a wide range of critical behaviours that determine the persistence of species and their success in ecological communities. We then evaluate several approaches to studying the ecological effects of warming and acidification, and identify knowledge gaps that need to be filled, to better understand how global change will affect marine populations and communities through altered animal behaviours. Our review provides a synthesis of the far‐reaching consequences that behavioural changes could have for marine ecosystems in a rapidly changing environment. Without considering the pervasive effects of climate change on animal behaviour we will limit our ability to forecast the impacts of ocean change and provide insights that can aid management strategies.     

影响小鼠体细胞脂质体法转染效率的因素

We studied the effects of the amount of liposome and plasmid, exposure time of cells to the liposome-plasmid complexes, number of cell passages and cell types on GFP gene transfection of mouse somatic cells. The maximal GFP transgene expression (30.7%) was achieved when mouse fetal fibroblast cells (MFFC) at 70%-90% confluence of passage 3 were exposed for 6 h to the complexes of 4 microg liposome (LipofectAMINE) and 0.3 microg plasmid (pEGFP-N1). Under these conditions, we compared the effect of the number (from primary to 15) of passages on the transfection efficiency of MFFC. The transfection efficiency of MFFC was 10.0%, 28.9% and 7.2% at the primary, 3rd and 15th passage, respectively, which indicated that the transfection efficiency decreased with passaging. When MFFC, mouse oviductal epithelial cells (MOEC) and mouse granulosa cells (MGC) were transfected at passage 3, the transfection efficiency was 27.8%, 13.7% and 14.2%, respectively, under the described transfection conditions. When the cell cycle stages of different cell types at transfection were examined, it was found that 17.2% of MFFC, 8.7% of MOEC and 9.9% of MGC were at M phases of the cell cycle. Examination of the cell cycle stages of MFFC at different passages showed that MFFC at the third passage had the highest percentage of M cells and the percentage decreased afterwards. This suggested that the transfection efficiency was correlated with the percentages of cells at M phase, and provided essential data for improvement of the transfection efficiency.     

Human sympathoadrenal system and adrenal cortex in prepubertal and pubertal periods

A complex study of the functional state of the sympathoadrenal system and adrenal cortex in 10–15-year-old children of both sexes was carried out using the indices of daily excretion of adrenaline, noradrenaline, 17-ketosteroids, and 17-hydroxycorticosteroids. A synchronism in the functional activity of the mediator component of the sympathoadrenal system as well as of the androgenic and glucocorticoid functions of the adrenal cortex was observed with age and during pubertal development of children. At the same time, heterochronic maturation was observed in the sex groups: in girls at the age of 10 and 12 years and in boys at the age of 14–15 years. The changes of different direction and intensity in the excretion of the studied hormones and hormonal metabolites were observed in the sex and age groups. A sharp increase in the daily excretion of glucocorticoid metabolites accompanied by a considerable decrease in the age index of noradrenaline secretion was observed in 14-and 15-year-old boys from beginning to end of school year; in addition, an increase in the daily excretion of sex hormones was observed at the age of 15 years. In girls, these indices varied within the age range, which points to a more sophisticated neuroendocrine control of physiological functions in girls during puberty.