The Johnston's organ of three homopteran species: A comparative ultrastructural study

A transmission electron-microscopy study has been carried out on the pedicel of three homopteran species, with particular focus on the leafhopper Scaphoideus titanus Ball. The two other species, the planthoppers Hyalesthes obsoletus Signoret and Metcalfa pruinosa Say, were investigated in order to compare the ultrastructure of the Johnston's organ (JO) among representatives of the Auchenorrhyncha group. The results showed the presence of a well developed JO located within the pedicel. Depending on the species the JO is made of 25 up to 72 scolopidia arranged in a coronal array. Each scolopidium is connective, heterodynal, amphinematic and hosts three structurally dissimilar sensory neurons. Two of them have a type 1 ciliary segment while the third bears a type 2 cilium. The type 2 dendrite tip is associated with a tubular cap and is longer than the others, ending into the cuticle at the base of the flagellum. Other scolopidia with one or two neurons were found in S. titanus, forming an accessory organ. The presence of such a well developed mechanosensory apparatus is discussed in relation with the lifestyle of the three species.     

Annual variation in reproductive parameters of Adélie penguins at Edmonson Point,Victoria Land,Antarctica

Annual egg and chick production and breeding success at the Adélie penguin (Pygoscelis adeliae) colony Edmonson Point (74°21′S–165°10′E), Victoria Land, is presented for eight breeding seasons between 1995 and 2005. During this period the colony consisted of 10–13 subcolonies and averaged 2098 ± 278 breeding pairs. A sample of over 100 nests (114–150), belonging to two subcolonies, was monitored each year. Some breeding parameters remained constant while others showed substantial annual variation. Laying date showed little variation, and laying was highly synchronous: 82.5% of clutches were initiated in a 10-day period, 9–18 November. In contrast, clutch size (1.77–1.97) and incubation period (34.4 ± 2.5) varied significantly. Variation among years was also recorded in hatching success (from 58 to 86%) and breeding success. This last parameter, measured as number of chicks reared to crèche per nest with eggs, varied between 0.34 and 0.97.     

Oral Mucosa Patch Test: A New Tool to Recognize and Study the Adverse Effects of Dietary Nickel Exposure

On contact with the skin, nickel may cause allergic contact dermatitis, which can be diagnosed by an epicutaneous patch test. Nickel exposure via the intestinal mucosa can induce diarrhea, abdominal pain, and swelling. The aim of the present study was to investigate the relationship between these symptoms and nickel intake by means of a novel oral mucosa patch test. Eighty-six patients with intestinal symptoms related to ingestion of nickel-containing foods were submitted to epicutaneous and oral mucosa patch tests for nickel. All patients with positive oral mucosa patch test results were subject to a low-nickel diet and monitored over time. Skin lesions were observed in 33 out of 86 (38.4%) patients evaluated by the epicutaneous patch test. Mucosal lesions were seen in 53 out of 86 (61.6%) patients given the oral mucosa patch test. After 2 months of a low-nickel diet, 52 out of 53 (98.1%) patients showed an improvement of their symptoms. There is a significant correlation between response time of the oral mucosa patch test and the latency of symptoms after ingestion of nickel-containing foods. Consequently, the oral mucosa patch test can be used to recognize and study the adverse effects of dietary nickel exposure that could be defined as allergic contact mucositis. A low-nickel diet is also shown to be an effective treatment for this condition.     

Evaluating the efficiency of enzyme accelerated CO2 capture: chemical kinetics modelling for interpreting measurement results

In this paper, the efficiency of the carbonic anhydrase (CA) enzyme in accelerating the hydration of CO₂ is evaluated using a measurement system which consists of a vessel in which a gaseous flow of mixtures of nitrogen and CO₂ is bubbled into water or water solutions containing a known quantity of CA enzyme. The pH value of the solution and the CO₂ concentration at the measurement system gas exhaust are continuously monitored. The measured CO₂ level allows for assessing the quantity of CO₂, which, subtracted from the gaseous phase, is dissolved into the liquid phase and/or hydrated to bicarbonate. The measurement procedure consists of inducing a transient and observing and modelling the different kinetics involved in the steady-state recovery with and without CA. The main contribution of this work is exploiting dynamical system theory and chemical kinetics modelling for interpreting measurement results for characterising the activity of CA enzymes. The data for model fitting are obtained from a standard bioreactor, in principle equal to standard two-phase bioreactors described in the literature, in which two different techniques can be used to move the process itself away from the steady-state, inducing transients.     

Rapid Assessment of Maturation Stage and Reproductive Mode in Centrolecytic Eggs of Stick Insects (Phasmatodea) Using DAPI Stain

A rapid three-step DAPI technique is proposed for detecting meiotic stages and sperm head evolution in yolky, fertilized stick insect eggs, which were difficult to analyze with other methods. Fixed eggs were freed from chorionic envelopes and stained directly in DAPI/PBS solution. After rinsing, eggs were singly squashed in a drop of mounting buffer and examined under a microscope with incident fluorescent illumination. The method was almost uniformly successful, and direct observation of nuclear structures, coupled with fluorometry, allowed easy recognition of bivalents, diads, pronuclei and their DNA content. The DAPI method proposed here appears particularly helpful for investigating unusual reproductive modes in eggs with large amounts of yolk.     

Résultats hémodynamiques et cliniques de la dissection, assistée par lunettes chirurgicales, des veines spermatiques au niveau de l’orifice inguinal interne

Inversion of venous flow is well visualized by colour duplex ultrasound and is the basic haemodynamic feature of varicocele. We tried to assess the value of dissection of branches of the spermatic vein in the internal inguinal ring using an operating microscope with a magnification of 4.5x. 16 patients were operated according to the ultrasound classification proposed by Hirsh et al. [8]. Varicocele was grade III in 2 cases, grade IV in 11 cases and grade V in 3 cases and was situated on the left in 13 patients and on the right in 3 patients. The diagnosis was based on clinical examination and colour duplex ultrasound. The operating time was 25–35 min. The incision was 1.5 to 2 cm long. No short-term complications or long-term hydrocele were observed. No reno-spermatic flow was observed on colour duplex ultrasound after six months. The mean testicular volume was 22 ml before surgery and did not change after the operation. This surgical technique is less invasive than the conventional retroperitoneal or laparoscopic procedures, and the incision is smaller than with the percutaneous technique. It is less radical than conventional microsurgery, but the operating time is shorter, and the surgical wound is smaller, sparing the artery and lymphatic vessels. In conclusion, this operation can be considered to be a good option in the surgical treatment of varicocele in view of its low complication rate, the absence of hydrocele, a minimally invasive procedure and the good haemodynamic results.