Osmotic adjustment in three-year-old seedlings of five provenances of maritime pine (Pinus pinaster) in response to drought

Three-year-old seedlings of five provenances of Pinus pinaster Ait. that differed in climatic conditions at their geographical origin were subjected to decreasing soil water availability. The degree of needle osmotic adjustment (OA) was estimated based on logarithmic plots of needle relative water content (RWC) against needle osmotic potential (Psi(pi)); i.e., lnRWC versus -ln(-Psi(pi)). There were significant differences among provenances in active OA (0.13 to 0.30 MPa for a decrease in RWC to 80%), and a clear negative relationship was found between OA and precipitation (650 to 1280 mm of mean annual rainfall) at the geographical origins of the provenances. A high osmoregulatory capacity contributes to the maintainance of positive turgor at low water potentials. We conclude that OA is one of the mechanisms underlying adaptation to drought in P. pinaster. Solute accumulation was about 2.3 times higher in the provenance from the driest site than in the provenance from the wettest site. The contribution of osmotic adjustment to differences in drought tolerance mechanisms among provenances is discussed.     

Receptor binding specificity and pathogenicity of Escherichia coli F165-positive strains isolated from piglets and calves and possessing pap related sequences.

Most of 82 F165-positive Escherichia coli isolated from calves and piglets with diarrhea or septicemia and possessing pap related sequences caused mannose-resistant, neuraminidase-resistant hemagglutination of human and bovine erythrocytes. Less than half of these isolates demonstrated binding specificity for the alpha-D-galactosyl-(1-4)-beta-D-galactopyranose or galactose-N-acetyl-alpha-(1-3) galactose-N-acetyl moieties recognized by P and F (or Prs) adhesins respectively. Binding specificity for the galactose-N-acetyl-alpha-(1-3) galactose-N-acetyl moiety was associated with isolates causing septicemia in newborn piglets.     

Thoracoscopic Lung Biopsies in Heaves‐Affected Horses Using a Bipolar Tissue Sealing System

Objective: To validate the use of the LigaSure? Vessel Sealing System (LVSS) to perform thoracoscopic lung tissue biopsies in heaves‐affected horses. Study design: Prospective clinical study. Animals: Heaves‐affected horses (n=12). Methods: Lung biopsies (n=34) were collected with the LVSS (2–4 biopsies/horse) in horses with and without clinical signs of heaves. Thoracoscope (13th intercostal space [ICS]) and 2 instruments (between the 12–15th ICS) portals were used. Selected clinical and arterial blood gas variables were monitored. Postoperative pneumothorax was evaluated. Depth of thermal injury to the surrounding tissue and representativeness of the biopsies were determined. Results: Mean surgical time was 22.9±8.0 minutes. The complication rate was 5.6%, and primarily related to a focal inadequate sealing of the biopsy margin. Five horses in exacerbation required intraoperative intranasal O₂. Mean PaO₂ was significantly lower in heaves‐affected horses with clinical signs compared with those without clinical signs. Postoperative pneumothorax was detected radiographically after 20 of the 34 procedures. One horse with clinical signs of heaves developed a fatal tension pneumothorax 5 days postoperatively despite close radiographic monitoring. Conclusion: Thoracoscopic lung biopsy using LVSS is a rapid and effective technique to harvest peripheral lung tissues from heaves‐affected horses. Although the complication rate was tolerable, tension pneumothorax was a potential life‐threatening complication because of incomplete lung sealing. Clinical Relevance: LVSS can be used with relative safety to perform thoracoscopic lung biopsy, but close postoperative monitoring is necessary to avoid tension pneumothorax.     

Laparoscopic Splenectomy for Treatment of Splenic Hemangiosarcoma in a Dog

Objective: To report laparoscopic splenectomy in a dog. Study Design: Clinical report. Animals: Mixed breed dog (n=1). Methods: Hemangiosarcoma was diagnosed by ultrasound‐guided fine‐needle aspiration of a splenic mass in an 11‐year‐old, 30 kg, mixed breed dog. No metastatic disease was identified during complete staging (chest radiographs, echocardiogram, and abdominal ultrasonography); however, cystic calculi were identified. Laparoscopic splenectomy using Ligasure V was performed through 3 portals and the calculi were removed by laparoscopic‐assisted cystoscopy. Results: Total surgical time was 2 hours and for laparoscopic splenectomy, 65 minutes. The celiotomy incision for splenic removal was 7 cm. The dog recovered uneventfully and was ambulatory 2 hours postoperatively. Conclusion: Laparoscopy with Ligasure V facilitated successful removal of a spleen with a 3 cm mass. Clinical Relevance: Laparoscopic splenectomy in dogs is feasible for removal of a normal‐sized spleen with a moderate‐sized mass.     

Litter decomposition in peatlands is promoted by mixed plants

Purpose

The carbon sink function of peatlands is primarily driven by a higher production than decomposition of the litter Sphagnum mosses. The observed increase of vascular plants in peatlands could alter the decomposition rate and the carbon (C) cycle through a litter mixing effect, which is still poorly studied. Here, we examine the litter mixing effect of a peat moss (Sphagnum fallax) and two vascular plants (Pinus uncinata and Eriophorum vaginatum) in the field and laboratory-based experiment.

Materials and methods

During the laboratory incubation, mass loss, CO₂ production, and dissolved organic carbon concentration were periodically monitored during 51 days. The collected data were then processed in a C dynamics model. The calculated enzymatic activity was correlated to the measured β-glucosidase activity in the litter. In the field experiment, mass loss and CO₂ production from litter bags were annually measured for 3 years.

Results and discussion

Both laboratory and field experiments clearly show that the litter mixture, i.e., Sphagnum-Pinus-Eriophorum, had a synergistic effect on decomposition by enhancing the mass loss. Such enhanced mass loss increased the water extractable C and CO₂ production in the litter mixture during the laboratory experiment. The synergistic effect was mainly controlled by the Sphagnum-Eriophorum mixture that significantly enhanced both mass loss and CO₂ production. Although the β-glucosidase activity is often considered as a major driver of decomposition, mixing the litters did not cause any increase of the activity of this exo-enzyme in the laboratory experiment suggesting that other enzymes can play an important role in the observed effect.

Conclusions

Mixing litters of graminoid and Sphagnum species led to a synergistic effect on litter decomposition. In a context of vegetation dynamics in response to environmental change, such a mixing effect could alter the C dynamics at a larger scale. Identifying the key mechanisms responsible for the synergistic effect on litter decomposition, with a specific focus on the enzymatic activities, is crucial to better predict the capacity of peatlands to act as C sinks.

     

Growth phenology in <Emphasis Type="Italic">Pinus halepensis</Emphasis> Mill.: apical shoot bud content and shoot elongation

Key message

The chronology of periods of organogenesis and elongation is highlighted in Pinus halepensis.The two first growth units of an annual shoot are preformed inside the bud during the previous year. The following growth units are formed during the spring or summer of the current year.

Context

Analysis of annual shoot length growth phenology is crucial to assess the impact of climate change on tree production. Little is known about the basic growth characteristics and the phenology of pines.

Aims

The present study disentangles the roles of shoot organogenesis vs elongation in the annual growth cycle of the polycyclic Aleppo pine.

Methods

Growth of young Pinus halepensis trees was monitored monthly for 1 year. At each monitoring date, the bud content and meristem dimensions of the main stem shoots apices were analyzed.

Results

The two first growth units of an annual shoot are preformed inside the bud during the previous year. The following growth units are formed during the spring or summer of the current year. The gap between a shoot organogenesis and its elongation may vary from 1 month, for the last growth unit, to half a year, for the first growth units.

Conclusion

Our results underline the importance of taking seasonal environmental conditions from both the previous and the current year into account, in order to study the plasticity of annual shoot growth and its response to climate change and variability.

     

Response to Chemical Alarm Cues under Weakly Acidic Conditions: A Graded Loss of Antipredator Behaviour in Juvenile Rainbow Trout

A wide variety of aquatic organisms, including juvenile salmonids, assess local predation risks using chemosensory cues. Such chemical cues are typically released from injured conspecifics and their detection may lead to species-typical antipredator behaviour, increasing the probability of prey to survive during predator encounters. Studies have demonstrated however, that under weak acidification (pH ~6.0), the response towards these chemical alarm cues is impaired. However, it remains unknown if the loss of response is graded (i.e., the behavioural response decreases with a reduction in pH) or if there is a threshold pH at which prey can no longer detect the alarm cues. We conducted two laboratory experiments to examine the effects of a graded reduction in pH on the behavioural response of juvenile rainbow trout to conspecific chemical alarm cues. The results of our first experiment suggest that at pH 6.6 and above, the alarm cues elicited a strong antipredator response, while alarm cues buffered to pH 6.2 did not (i.e. not different from distilled water). However, alarm cues buffered to pH 6.4 elicited a weak response, suggesting a graded response. We directly tested this in our second experiment using a repeated measures design. The response to alarm cues at varying pH levels did indeed follow a graded loss of function. Together, our results suggest that juvenile rainbow trout exhibit a reduction in the response to conspecific alarm cues proportional to ambient acidity and that the response to these critically important cues is lost at pH below 6.4. As the detection and response to these chemical alarm cues have been shown to confer direct survival benefit to individuals, these results are therefore presented in relation to possible sub-lethal effects of anthropogenic acidification to freshwater fish.     

The lack of effect of isoflavones on high-density lipoprotein cholesterol concentrations in adolescent boys: a 6-week randomised trial

BACKGROUND: A substantial fall in high-density lipoprotein cholesterol (HDL-C) during puberty in boys, but not girls, has been reported in Western populations. The fall in boys is believed to be due to hormonal changes - androgens have been shown to be associated with lower HDL-C, whereas oestrogens are associated with higher HDL-C. The fall in HDL-C during puberty was not observed, however, in a study of Moslem boys in Israel, nor in a group of Japanese boys. A diet high in phyto-oestrogens may account for the lack of a fall in HDL-C in these populations. OBJECTIVE: To examine the effect of dietary supplementation with phyto-oestrogens on the HDL-C concentration of adolescent boys from a Western population. We hypothesised that dietary supplementation of 50 mg of the isoflavones daidzein and genistein would produce a 12% higher HDL-C concentration than in controls at the end of a 6-week intervention period. DESIGN: A randomised controlled trial. SETTING: Hellyer College in Burnie (Tasmania, Australia). SUBJECTS: Adolescent boys (aged 16-18 years) were recruited through a letter sent to parents. A total of 132 eligible participants enrolled and five subjects withdrew from the trial. RESULTS: No significant increase in HDL-C was observed in the treatment group (-0.02 mmol l-1, standard error (SE)=0.03, P = 0.53) or the placebo group (0.05 mmol l-1, SE = 0.03, P = 0.11). CONCLUSIONS: Factors other than isolated dietary isoflavones may be responsible for the lack of fall in HDL-C during puberty in Japanese and Moslem boys.     

What can be expected of a T90 extension piece to improve selectivity in bottom trawl multispecific fisheries in the Bay of Biscay?

In the Bay of Biscay, the selective properties of otter trawls have mainly been studied with regard to single species. However, for bottom trawl multispecific fisheries targeting fish, it remains challenging to find a selective device capable of limiting catches of small individuals of several species without commercial losses. The present study focuses on an innovative technical solution to reduce catches of undersized individuals in a multispecies bottom trawl fishery in the Bay of Biscay. We tested a cylinder made of 100-mm diamond meshes turned at 90°, namely T90 inserted in the extension piece. We present the selectivity results obtained for six commercial species. This device allows the escape of small Solea solea, Trachurus trachurus and Spondyliosoma cantharus individuals. No commercial losses of Sepia officinalis were recorded. Patterns for Dicentrarchus labrax and Mullus surmuletus require further investigation due to limited fish size ranges in the dataset.