有机物-金属相互作用对重金属负载土柱中粘土矿物吸附剂再生的影响

Natural clay minerals can play an important role in crude remediation of wastewater polluted with the heavy metals (HMs) Cu,Zn and Ni.The presence and timing of addition of natural dissolved organic matter (DOM) have a significant effect on the HM removal by clay mineral sorbents.However,the influence of the presence of DOM on the remediation of the used clay mineral sorbents once saturated with HMs is largely unknown.To resolve this,clay mineral-rich soil column of varying composition,loaded (i) with Cu,Zn and Ni only,(ii) first with DOM followed by Cu,Zn and Ni,or (iii) with DOM,Cu,Zn and Ni simultaneously,was used in a set of desorption experiments.The soil columns were leached with 0.001 mol L-1 CaCl2 dissolved in water as control eluent and 0.001 mol L-1 CaCl2 dissolved in DOM as treatment eluent.During the preceding loading phase of the sorbent,the timing of DOM addition (sequential or concurrent with HMs) was found to have a significant influence on the subsequent removal of the HMs.In particular when the column was loaded with DOM and HMs simultaneously,largely irreversible co-precipitation took place.Our results indicate that the regeneration potential of clay mineral sorbents in wastewater treatment will be significantly reduced when the treated water is rich in DOM.In contrast,in manured agricultural fields (where HMs enter together with DOM),HM mobility will be lower than expected from interaction dynamics of HMs and clay minerals.     

Electrophoretic evidence of the integrity of humic substances separated by means of electrofocusing

The alkaline extracts of an andic soil, a Bhir horizon of a spodic soil and leonardite which, after electrofocusing, displayed bands in the neutral region of the pH gradient, were fractionated by electrophoresis in phosphate buffer at pH 6.5. The non-migrated fraction gave an electrofocusing profile containing only bands focused at pH values above that of the electrophoretic separation. Electrophoresis in sodium acetate buffer pH 4.8 of humic substances extracted from peat permitted isolation of bands focusing above pH4.8. The distribution of metals after electrophoresis suggests that a great part of humic substances which originate bands above pH 6.5 consists of negatively charged Fe and Al complexes. Addition of EDTA to solutions of humic substances extracted from the samples resulted in the disappearance of bands in the neutral region of the pH gradient in the electrofocusing profile of the Bhir sample, while a consistent lessening of these bands was observed in the leonardite and andic soil samples.     

Co-inoculation of selected nodule endophytic rhizobacterial strains with Rhizobium tropici promotes plant growth and controls damping off in common bean

Production of common bean(Phaseolus vulgaris)is limited by the occurrence of damping off(rhizoctoniosis),which is caused by the fungus Rhizoctonia solani.However,the co-inoculation of plant growth-promoting rhizobacteria(PGPR)involved in biological control along with diatomic nitrogen(N2)-fixing rhizobia can enhance N nutrition and increase production.In this context,finding microorganisms with synergistic effects that perform these two roles is of fundamental importance to ensure adequate yield levels.The aim of this study was to evaluate the effects of co-inoculation of nodule endophytic strains of the genera Bacillus,Paenibacillus,Burkholderia,and Pseudomonas with Rhizobium tropici CIAT 899,an N2-fixing rhizobial strain,on the biocontrol of damping off and growth promotion in common bean plants.Greenhouse experiments were conducted under axenic conditions using the common bean cultivar Pérola.The first experiment evaluated the potential of the 14 rhizobacterial strains,which were inoculated alone or in combination with CIAT 899,for the control of R.solani.The second experiment evaluated the ability of these 14 rhizobacterial strains to promote plant growth with three manners of N supply:co-inoculation with CIAT 899 at low mineral N supply(5.25 mg N mL^-1),low mineral N supply(5.25 mg N mL^-1),and high mineral N supply(52.5 mg N mL^-1).The use of rhizobacteria combined with rhizobia contributed in a synergistic manner to the promotion of growth and the control of damping off in the common bean.Co-inoculation of the strains UFLA 02-281/03-18(Pseudomonas sp.),UFLA 02-286(Bacillus sp.),and UFLA 04-227(Burkholderia fungorum)together with CIAT 899 effectively controlled damping off.For the common bean,mineral N supply can be replaced by the co-inoculation of CIAT 899 with plant growth-promoting strains UFLA 02-281/02-286/02-290/02-293.Nodule endophytes UFLA02-281/02-286 are promising for co-inoculation with CIAT 899 in the common bean,promoting synergy with rhizobial inoculation and protection against disease.     

A Case of Bovine Linear Keratosis

Résumé— Cet article décrit un cas de nevus épidermique linéaire unilatéral chez un veau de six mois. Histologiquement, les lésions consistaient en une alternance de zones d'hiper et de parakératose avec une inflammation dermique distincte. Le diagnostic de nevus linéaire inflammatoire a été posé sur la base des lésions macro et microscopiques. [Deprez, P., De Coole, H., Sustronk, B., Muille, E., Ducatelle, R. A case of bovine linear keratosis (A propos d'un cas de kératose linéaire chez un bovin).
Resumen— En este artículo se describe un caso de nevos epidérmicos lineares unilaterales en un bo vino de seis meses de edad. Las lesiones histológicas consistian zonas donde se alternaba hiper i paraqueratosis, mientras que la dermis presentaba una marcada inflamación. Se diagnosticó un nevo epidérmico verrucoso linear e inflamatorio a partir de las lesiones clinicas e histopatológicas [A case of bovine linear keratosis (Un caso de queratosis linear bovina).
Abstract— This report describes a case of unilateral linear epidermal nevi in a 6-month-old bovine. Histologicalli, the lesions consisted of alternating areas of hiper- and parakeratosis with a distinct dermal inflammation. A diagnosis of inflammatori linear verrucous epidermal nevus was made based on the clinical and histopathological lesions.     

A genetic description of two selected strains of rabbits

Two strains of rabbits (strains 1077 and 2066) have been selected since 1974 for increased litter size. Each strain is split into a fixed number of reproduction groups. The mating scheme is similar to random non-sib herd mating. The number of animals per generation is higher in strain 1077 (28 mated bucks and 104 mated does) than in strain 2066 (17 and 59, respectively). The increase of the inbreeding coefficient is higher in strain 2066 than in strain 1077 (27 and 21%, respectively, at generation 20). The mean standard deviation of the individual inbreeding coefficients per generation is low (less than 4%) in both strains. Short-term inbreeding is stable over generations. The observed inbreeding effective size Ne _f and the observed familial structure effective size Ne _h converge to the same value. The number of founder genomes still present in the genetic pool of the generation decreases regularly: from 5.6 to 2.4 between G6 and G20 for strain 1077. It is a bit lower over time for strain 2066 (from 5.7 to 1.9 between G6 and G20). The effective number of founders is nearly twice as small as the total number: 30 for strain 1077 and 15 for strain 2066. The effective number of major ancestors decreases slightly in strain 1077 (13.6 in G6 and 12.9 in G20) and regularly in strain 2066 (13.8 in G6 and 9.4 in G20).     

Fiber Types Distribution in the Digastric Muscle of Tufted Capuchin Monkey (Cebus apella)

Fiber types distribution in the diagastric muscle of tufted capuchin monkey was studied by means of NADH-TR, myosin-ATPase, after alkaline and acid preincubations and SDH histochemical reactions. Three different types of fibers were found presenting an equal distribution. The percentage and types of fibers were as follow: 18.2 % SO (Slow Oxydative), 38.4 % FOG (Fast Oxydative Glycolytic) and 43.4 % FG (Fast Glycolytic). FG fibers revealed the largest area. The relatively high concentration of fast twitch (81.2 %) seems to indicate this muscle is involved with the acceleration and fast speed of jaw movements. Aerobic metabolism represented by SO + FOG fibers (56.6 %) suggestes that this muscle possesses an additional role than that related to the lowering of the jaw.     

Magnetotactic bacteria at the geomagnetic equator

Magnetotactic bacteria are present in fresh water and marine sediments of Fortaleza, Brazil, situated close to the geomagnetic equator. Both South-seeking and North-seeking bacteria are present in roughly equal numbers in the same samples. This observation is consistent with the hypothesis that the vertical component of the geomagnetic field selects the predominant polarity type among magnetotactic bacteria in natural environments.