Unraveling the origin of <Emphasis Type="Italic">Coffea arabica</Emphasis> ‘Bourbon pointu’ from La Réunion: a historical and scientific perspective

Coffee is one of the main products on the international markets, in association with oil, corn, sugar, and paper pulp. The history of coffee-tree cultivation is incompletely documented, both regarding its domestication in Africa, and its assisted dispersal throughout the world. This review focuses on the coffee mutant, Coffea arabica ‘Laurina’ (Chevalier A in Encyclopedie Biologique. Vol 28, 1947), also named ‘Bourbon pointu’. This plant is generally acknowledged to have been selected in the island of ‘Bourbon’ (La Réunion) from a field at the beginning of the 19th century. Compared with the common ‘Bourbon’ variety, ‘Bourbon pointu’ trees are dwarf, with a characteristic Christmas-tree shape and the beans have an excellent cup quality. Although cited many times in literature, the origin of this variety is ambiguous and is largely discussed even today with increasing confusion, particularly in books and local newsletters. This article provides a thorough historical and bibliographical review of coffee cultivation in La Réunion, which leads to an understanding of the bottleneck responsible for the low genetic diversity of the ‘Bourbon’-type modern varieties. Complemented by a review of the scientific studies conducted on this subject, confirmation of the veracity of the various historical accounts becomes possible, and appropriate conclusions on the origin of the ‘Bourbon pointu’ are derived. Although historical texts provide important information and represent priceless resources that give direction to scientific research, it is clear that this same research makes it possible, in turn, to clarify and to interpret historical texts.

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.     

Physical properties and termite durability of maritime pine Pinus pinaster Ait., heat-treated under vacuum pressure

An original heat treatment performed under vacuum pressure was investigated. Maritime pine samples were treated at six different temperatures: 140, 160, 180, 200, 230 and 260°C. The physical and mechanical consequences, i.e. bending strength (MOR), modulus of elasticity (MOE), hygroscopic behaviour, equilibrium moisture contents and anti-swelling efficiency (ASE) were studied. A no-choice feeding test according to the NF EN 117 standard was achieved. Temperatures up to 200°C had no significant effect on wood properties. However, at 230 and 260°C, the decrease in MOR was severe, reaching 42.5 and 62.5%, respectively. Whatever the treatment conditions, wood samples were still highly degraded by termites, revealing no increase in their durability.     

Variation in aggressiveness is detected among Puccinia triticina isolates of the same pathotype and clonal lineage in the adult plant stage

Puccinia triticina reproduces asexually in France and thus individual genotype is the unit of selection. A strong link has been observed between genotype identities (as assessed by microsatellite markers) and pathotypes (pools of individuals with the same combination of qualitative virulence factors). Here, we tested whether differences in quantitative traits of aggressiveness could be detected within those clonal lineages by comparing isolates of identical pathotype and microsatellite profile. Pairs of isolates belonging to different pathotypes were compared for their latent period, lesion size and spore production capacity on adult plants under greenhouse conditions, with a high number of replicates. Isolates of the same pathotype showed remarkably similar values for the measured traits, except in three situations: differences were obtained within two pathotypes for latent period and within one pathotype for sporulation capacity. One of these differences was tested again and confirmed. This indicates that the average aggressiveness level of a leaf rust pathotype may increase without any change in its virulence factors or microsatellite profile.     

Racemic and enantiopure synthesis and physicochemical characterization of the novel taste enhancer N-(1-carboxyethyl)-6-(hydroxymethyl)pyridinium-3-ol inner salt

Convenient syntheses were developed to obtain on a multigram scale the novel taste enhancer N-(1-carboxyethyl)-6-(hydroxymethyl)pyridinium-3-ol 1, called alapyridaine, as a racemic mixture and as pure (+)-(S) and (-)-(R) enantiomers, respectively. 5-(Hydroxymethyl)-2-furaldehyde was used as key intermediate and was reacted with l-alanine under alkaline conditions to obtain racemic 1. Alternatively, reductive amination of 5-(hydroxymethyl)-2-furaldehyde with Raney-Ni/hydrogen and l- or d-alanine followed by mild oxidation led to (+)-(S)-1 and (-)-(R)-1, respectively. Racemization was promoted under alkaline and boiling conditions via a carbanion, the formation of which was facilitated by the electron-withdrawing effect of the iminium cation and the resonance-stabilizing capacity of the pyridinium moiety. Under these conditions, 1 was obtained in a 1:1 mixture of the phenol (1) and phenolate (1-H) forms as shown by X-ray diffraction. Racemic 1 formed monoclinic crystals of high molecular organization in which the phenol-type (RS)-1, the phenolate-type (RS)-1-H, sodium cations, and ethanol molecules are present. The crystal structure of [Na(1)(1-H).(C(2)H(6)O)] shows one-dimensional mu(2)-bridging-oxygen polymers stabilized by a three-dimensional network of ionic, hydrogen bond, and pi-stacking interactions with channels occupied by solvent molecules.     

Persistence of Bacillus thuringiensis israelensis (Bti) in the environment induces resistance to multiple Bti toxins in mosquitoes

BACKGROUND: The simultaneous production of six different toxins by Bacillus thuringiensis israelensis (Bti) is thought to delay the evolution of resistance in treated mosquito populations. Recent studies have shown that Bti can persist and proliferate in the environment, thereby imposing continuous selective pressure on mosquito populations, raising concerns about the long‐term effectiveness of this bioinsecticide. In order to evaluate the effect of Bti persistence on the evolution of resistance, the authors selected a laboratory Aedes aegypti L. strain with field‐collected leaf litter containing Bti toxins. RESULTS: It is shown that resistance to each individual Bti toxin (up to 30‐fold) can be obtained after only a few generations of selection. However, the resistance to commercial Bti and to environmental Bti remains low (twofold and 3.4‐fold respectively) in the selected strain. Furthermore, some selected individuals exhibited resistance to Cry4B but not to Cry4A, suggesting that two distinct resistance mechanisms are involved in the resistance to these two toxins. CONCLUSION: Considering that resistance to Cry toxins might act as a first step to resistance to a complete Bti toxin mixture, the present results highlight the importance of testing each toxin individually in order accurately to monitor Bti toxin resistance evolution in field populations. Copyright © 2010 Society of Chemical Industry     

Modeling a weak turbulent flow in a narrow and wavy channel: case of micro-irrigation

The baffle-fitted labyrinth channel is commonly used in micro-irrigation systems. The flow in this labyrinth channel has a rather low-Reynolds number. In addition, emitter clogging, which is the major drawback of the micro-irrigation technique, is significantly related to flow characteristics. In order to design an anti-clogging emitter with a good performance, the hydrodynamics must be understood and analyzed. As CFD modeling is nowadays the most efficient approach for improving emitter geometry, this paper presents assessment of several k–\(\varepsilon\) turbulence models for computation of micro-irrigation emitter hydrodynamics. The objective is to determine the simplest and most efficient model to improve emitter conception, in terms of both discharge/pressure loss and limitation of the areas where low velocity is likely to generate emitter clogging. Low-Reynolds number k–\(\varepsilon\) models are often assumed to be more suitable for the labyrinth-channel flow since these models have no wall functions, they can take into account low turbulence levels and they account for the effect of damped turbulence. The low-Reynolds number k–\(\varepsilon\) models used in the present study are compared to high-Reynolds number k–\(\varepsilon\) models. Very different trends are observed between low-Reynolds number k–\(\varepsilon\) models. Some models reproduce a turbulent behavior, while others reproduce a laminar behavior. The head loss analysis reveals that, contrary to classical smooth pipe flow, the contribution of turbulent dissipation cannot be neglected since its contribution is larger than wall friction ones. This feature explains why different models can induce quite different flow behavior.     

Sugar fragmentation in the maillard reaction cascade: isotope labeling studies on the formation of acetic acid by a hydrolytic beta-dicarbonyl cleavage mechanism

The formation of acetic acid was elucidated based on volatile reaction products and related nonvolatile key intermediates. The origin and yield of acetic acid were determined under well-controlled conditions (90-120 degrees C, pH 6-8). Experiments with various 13C-labeled glucose isotopomers in the presence of glycine revealed all six carbon atoms being incorporated into acetic acid: C-1/C-2 ( approximately 70%), C-3/C-4 ( approximately 10%), and C-5/C-6 (approximately 20%). Acetic acid is a good marker of the 2,3-enolization pathway since it is almost exclusively formed from 1-deoxy-2,3-diulose intermediates. Depending on the pH, the acetic acid conversion yield reached 85 mol % when using 1-deoxy-2,3-hexodiulose (1) as a precursor. Hydrolytic beta-dicarbonyl cleavage of 1-deoxy-2,4-hexodiuloses was shown to be the major pathway leading to acetic acid from glucose without the intermediacy of any oxidizing agents. The presence of key intermediates was corroborated for the first time, i.e., tetroses and 2-hydroxy-3-oxobutanal, a tautomer of 1-hydroxy-2,3-butanedione, also referred to as 1-deoxy-2,3-tetrodiulose. The hydrolytic beta-dicarbonyl cleavage represents a general pathway to organic acids, which corresponds to an acyloin cleavage or a retro-Claisen type reaction. Although alternative mechanisms must exist, the frequently reported hydrolytic alpha-dicarbonyl cleavage of 1 can be ruled out as a pathway forming carboxylic acids.