Status and restoration of peatlands in northern Europe

Environmental management of peatlands,landscape ecology and protection of keybiotopes have created needs and pressure torestore drained peatlands to natural mireecosystems. Here, we summarize differentapproaches and restoration techniquesdeveloped for peatland management inEstonia, Sweden, and Finland wherepeatlands are abundant. Without rewetting,plant colonisation on abandoned cut-awayareas is slow due to harsh hydrological andmicroclimatic conditions. However, after restoration, cut-away peatlands may returnto a functional state close to that ofpristine mires, and therefore restore a netcarbon sink function within a few years. Inaddition, restoration techniques can helpto create buffer zones between terrestrialand limnic ecosystems that reduces thenutrient loading imposed on watercourses byforestry operations. Restoration may alsobe important for peatland conservationprograms as drained peatlands are part ofpresent and future conservation areas.Finally, restoration actions in themselvescan have negative environmental impacts.For instance, inundation of peat surfacesresulting from the rewetting process oftenincreases phosphorus leaching. Efforts onpeatland restoration should focus onenvironmental monitoring, research onrestoration and its environmental impact aswell as public relations activities. Inthat respect, knowledge transfer betweenacademics and managers should generatesynergy benefits.     

Relative Sensitivity of the Ocular Trigeminal, Nasal Trigeminal and Olfactory Systems to Airborne Chemicals

We measured thresholds for eye irritation and odor in homologousseries of alcohols (ethanol, 1-butanol, 1-hexanol and 1-octanol),ketones (2-propanone, 2-pentanone, 2-heptanone and 2-nonanone),and alkylbenzenes (toluene, ethyl benzene and propyl benzene).Eye irritation thresholds were well above odor thresholds forall series. Both sensory thresholds declined with carbon chainlength, a trend that has implicated lipophilicity in the potencyof these and related stimuli. Eye irritation thresholds wereremarkably close to nasal pungency thresholds obtained previouslyin persons lacking olfaction (i.e. anosmics). The agreementbetween the two thresholds implies that, despite differencesin the mucus layer at the two sites and in the epithelial tissueitself, there is remarkable similarity at the site of stimulation.As a practical matter, the eyes could serve as the sites toassess potency for induction of nasal pungency, an assessmentpreviously limited to testing anosmics. Presumably, for ourbrief stimulus presentations (1–3 s), the differencesbetween ocular and nasal mucosae have little relevance to chemicalsensitivity. Studies of the ability of homologous chemical seriesto evoke threshold eye irritation, nasal pungency and odor notonly have practical value, but also can help to define the physicochemicalproperties of the receptor and perireceptor biophases. ¹Present address: Department of Surgery (Otolaryngology), UCSDMedical Center, University of California, San Diego, USA     

Et si Janet était plus actuel que Freud ?

A return to the work of Pierre Janet is prompted by the desire to satisfy a need as yet unfulfilled by Freudian analysis, addressing such questions as: what triggers a feeling, what does that feeling mean to the consciousness, what behavior does it trigger and how does belief in the feeling’s legitimacy strengthen the momentum of the behavior until it enables an active effort (not to be confused with an impulse), while its disturbance, (which is in fact an impulse), shows how derivations and dissociations can overlap, resulting in immobility and escape behavior, or neurosis according to Janet. It would be extremely wise to rediscover the heuristic relevance of Janet’s analysis today. And this is exactly what is happening at the moment all over the world, particularly in Japan, Germany, Canada, Holland, Russia and the USA: not in France, however…     

Effect of β-Bungarotoxin on the Release of Endogenous Amino Acids from the Sensorimotor Cortex

Abstract: β-Bungarotoxin, a snake neurotoxin purified from the venom of Bungarus multicinctus , caused a significant increase in the in vivo release of glutamate from the superfused sensorimotor cortex of awake animals. A smaller effect on GABA release was observed, but no change was detected in the release of six other amino acids measured. The effects on glutamate and GABA release were entirely blocked by tetrodotoxin (1 μM) and were reversible when the cortical tissue was washed with saline.     

Differential mechanisms to induce dehydration tolerance by abscisic acid and sucrose in Spathoglottis plicata (Orchidaceae) protocorms

Abscisic acid (ABA) and sucrose are known to induce dehydration tolerance of in vitro plant cells and tissues. The present study reports the presence of different mechanisms by which sucrose and ABA improve dehydration tolerance of Spathoglottis plicata (orchid) protocorms. Orchid protocorms were generated aseptically from seeds on Murashig and Skoog medium, and then treated for 7 d in medium containing 10 mg L^?1 ABA and/or 10% (w/v) sucrose. Dehydration tolerance of protocorms was determined at ～25 °C under various drying conditions at relative humidity from 7 to 93%. The actual rate of water loss (i.e. drying rate) was determined using the rate constant of tissue water loss during drying according to the first‐order kinetics. Drying rate affected dehydration tolerance. ABA treatment reduced drying rate and increased dehydration tolerance of protocorms at all relative humidity values tested. However, when compared on the basis of actual drying rates, there was no difference in dehydration tolerance between control and ABA‐treated protocorms, suggesting that ABA‐induced tolerance was correlated with the drying rate reduction. Sucrose treatment was more effective than ABA treatment for the induction of dehydration tolerance. Interestingly, sucrose only slightly affected drying rate. ABA treatment significantly enhanced the synthesis of dehydrin, whereas sucrose treatment primarily resulted in sucrose accumulation. Sucrose treatment also affected protein turnover during drying, causing a significant decrease in protein content in protocorms. Slow drying promoted the degradation of high molecular weight proteins and enhanced the synthesis of low molecular weight dehydrin. The data suggest that different physiological mechanisms are probably involved in the induction of dehydration tolerance by ABA and sucrose treatment.     

Micropropagation of Bambusa edulis through nodal explants of field-grown culms and flowering of regenerated plantlets

Nodal explants obtained from 10-year-old field-grown culms of Bambusa edulis produced multiple shoots on a Murashige-and-Skoog-based medium supplemented with 0.1 mg/l of thidiazuron (TDZ). Hundreds of regenerated shoots rooted well on a medium supplemented with 0.01 mg/l TDZ and 0.5 mg/l 2,4-dichlorophenoxyacetic acid and were successfully transferred to soil for field trials. Albinism occurred at the rate of about 30% among the regenerated shoots, and isolated albino shoots also proliferated on the medium containing TDZ. Some of the green and albino shoots also flowered on the medium containing TDZ. A potted plant also flowered and survived after flowering. Received: 20 August 1997 / Revision received: 12 December 1997 / Accepted: 12 January 1998     

Defining the Niche of Vibrio parahaemolyticus During Pre- and Post-Monsoon Seasons in the Coastal Arabian Sea

The bacteria Vibrio parahaemolyticus is an important component of coastal ecosystems worldwide, and in recent years, V. parahaemolyticus has caused several cases of food-borne gastroenteritis. However, research investigating which parameters are important in regulating V. parahaemolyticus abundance in tropical areas with relatively stable temperatures and salinity are largely lacking. The objective here was to investigate which environmental forces are driving elevated abundances of V. parahaemolyticus in a tropical oligotrophic coastal area in the Arabian Sea. We analysed a large number of environmental parameters in parallel with cell densities of V. parahaemolyticus and Vibrio spp. Abundance data was obtained using real-time PCR, during two different sampling periods, representative for two distinct seasons. Water temperature and salinity were stable during and between sampling periods, but V. parahaemolyticus abundances were on average six times higher during the first sampling period in December, compared to the second period in February–March. V. parahaemolyticus abundance was found to be positively correlated to inorganic phosphate concentration and copepod abundance. We thus hypothesise that these are important factors regulating V. parahaemolyticus abundance in coastal tropical areas during these periods.