Earthworms have become a potential source of multi‐beneficial bacteria and effective bioinoculants. Seed biopriming is an efficient inoculation method to apply bacteria prior to sowing, which ...enhances the chances of bacterial candidates to colonize the rhizosphere and/or establish a liaison with the plant. In this study, we evaluated plant growth‐promoting traits of bacterial strains isolated from the earthworm’s Aporrectodea molleri chloragogenous tissue. In addition, we investigated their prospective use as biopriming agents to enhance Zea mays germination and seedling growth. Results were subjected to principal component analysis for potential correlations between the studied parameters. The bacterial strains displayed different in vitro plant growth‐promoting characteristics and were efficient when applied in vivo as they significantly increased maize germination rate (26–78%), root elongation (67–84%), seedlings fresh weight and dry weight. Aeromonas encheleia TC22 was the most significant strain to influence germination due to its high ability to produce indole‐3‐acetic acid, and along with Pseudomonas azotoformans TC1, they were the most proficient at enhancing seedling root elongation and biomass, which was significantly correlated with their in vitro plant growth‐promoting traits. Our findings indicate that isolates TC22 and TC1 are potent bio‐primers for maize seeds and should be tested further for their use as biopriming inoculants.
Significance and Impact of the Study: Earthworms harbour interesting bacteria that exhibit multiple beneficial plant growth‐promoting (PGP) traits and could be applied as bioinoculants to enhance crop production. However, the bacteria–plant connection is rarely successful in field application. Bacteria isolated from the chloragogenous tissue of the earthworm Aporrectodea molleri were able to solubilize phosphate and potassium and produce the phytohormone indole‐3‐acetic acid, ammonium and nitrate. Zea mays seeds inoculated before sowing with those bacteria significantly increased the germination rate, seedlings’ root elongation and biomass compared with the control. Our results demonstrate the potential use of our strains as biopriming agents for maize seeds.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
This study was aimed to investigate the effect of earthworms after their decomposition on yeast growth. To achieve this objective, in vitro crude soluble extracts were prepared from two earthworms ...lots: freshly harvested from the field “FHE” and the other previously starved for one week “SE”. The dry residues of these two crude extracts were used at different concentrations as a solid media for the growth of two yeast species: one “Candida tropicalis” got from another laboratory and the other was isolated by our team from earthworms’ casts “Filobasidium uniguttulatum”, and their growth was evaluated by colonies counting. The results obtained, compared with the Sabouraud Dextrose Agar (SDA), showed that the growth of both yeast isolates was significantly higher on mediums prepared using exclusively earthworms’ crude extracts and agar. Optimal growth was obtained at a concentration corresponding to 0.375g/100 mL of earthworms’ soluble matter of the two types of earthworms’ lots. These results affirmed the richness and the diversification of those extracts, in nutrients and growth factors, that comes mainly from the intrinsic composition of earthworm’s body biomass. The efficiency of the FHE and SE extracts for cultivation of yeast shows their possible use as a culture media that may be applied to other soil microorganisms and even in vivo as soil amendments or biofertilizers.
Zoonotic cutaneous leishmaniasis (ZCL), due to Leishmania major, and chronic CL, due to L. tropica, are endemic in the governorate (administrative subdivision) of Tataouine (southeast Tunisia). This ...study aims to analyze epidemiologic, clinical, parasitologic, and entomologic data collected during the 2012-2013 epidemic in Ksar Ouled Dabbab (KOD).
The KOD health care center diagnosed 164 CL cases from July 2012 to March 2013, identifying 21 Leishmania isolates and local sandflies.
The incidence rate of CL in KOD was around 27.5/1000 inhabitants. The age groups most strongly affected were children younger than 10 years (19.9%) and those aged 10-20 years (23.1%). The number of patients with multiple lesions (67.9%) and their location on limbs (71.3%) indicated ZCL. This hypothesis is supported by the high proportions of L. major (81%) and Phlebotomus papatasi found.
The epidemiologic and clinical profiles of the cases and the predominance of L. major and P. papatasi confirm that the recent outbreak in KOD was related to ZCL. It probably followed recent environmental changes and transmission spread from adjacent neighboring foci.
Determination of rhizogenous excretion area at Lumbricus terrestris L. The partition of the Lumbricus terrestris L., after the observation of different excretory orifices on its bodily surface at the ...40th segment allowed to determine the body parts actually involved in the production of rhizogenous substances. Spectrophotometric analysis and biological tests conducted on Phaseolus vulgaris L. from worm's anterior and posterior extracts parts revealed that both parts participate in the production of indol-derived substances. However, this production may be more important at the level of the worm's posterior parts. It is therefore hypothesized that only those excretory orifices commun to all segments are involved in this production. Chromatographic and spectrophotometric analysis conducted on living worms from their dorsal and ventral prints of cutaneous excretions extracted directly from chromatographic plates, revealed the presence of basic indol-derived substances throughout the length of the worm, particularly at the level of coelomic and urinary excretory orifices.
Cutaneous excreta of earthworms are an increasing interest in many areas of scientific research. Our study aims to develop an electrical technique for stimulating the production of these cutaneous ...excretions more efficient and less harmful than that using chemical stimulation with petroleum ether. This study made it possible to define the optimal electrical parameters ensuring the obtaining of a maximum rate of excretion. These parameters are respectively: a voltage (U) of 20V, a pulse frequency (F) of 100 stimulations per second and a stimulation time (T) of 5 minutes. The comparative study of this new technique of electrical stimulation compared to chemical stimulation shows statistically very comparable excretion production rates (p<0,05). However, electrical stimulation offers considerable advantages relating to the physical integrity of the worms (lower mortality rate than that obtained during chemical stimulation), the short duration of stimulation and the ease of recovery of sticky excretions. In addition, the electrical stimulation technique offers the possibility of reusing the worms in other electrical stimulations after a rest period of 3 weeks.
Les excrétions cutanées des vers de terre présentent un intérêt de plus en plus grandissant dans de nombreux domaines de la recherche scientifique. Notre étude a pour but la mise au point d’une technique électrique pour la stimulation de la production de ces excrétions cutanées plus performante et moins nocive que celle utilisant la stimulation chimique à l’éther de pétrole. Cette étude a permis de définir les paramètres électriques optimaux assurant l’obtention d’un taux d’excrétions maximal par la stimulation électrique. Ces paramètres sont respectivement : une tension (U) de 20V, une fréquence d’impulsions (F) de 100 stimulations par seconde et un temps de stimulation (T) de 5 minutes. L’étude comparative de cette nouvelle technique de stimulation électrique par rapport à la stimulation chimique montre des taux de production d’excrétions statistiquement très comparables (p<0,05). Cependant, la stimulation électrique offre des avantages considérables relatifs à l’intégrité physique des vers (taux de mortalité plus faible que celui obtenu lors de la stimulation chimique), à la courte durée de stimulation et à la facilité de récupération des excrétions gluantes. En plus, la technique de stimulation électrique offre la possibilité de réutilisation des vers dans d’autres stimulations électriques après un temps de repos de 3 semaines.
Cette étude tente d’élucider le rôle de Lumbricus terrestris dans la régulation du pH. L’approche expérimentale adoptée permet d’écarter toutes les interférences possibles avec les composantes du ...sol. L’immersion des vers dans les solutions réactionnelles à différents pH acides a permis la délimitation in vitro d’une zone de tolérance comprise entre pH = 2 et pH = 7. Dans cette zone, plus le pH s’écarte de la neutralité plus la réaction des vers est intense et plus la production des excrétions cutanées est abondante. On assiste à une tendance à la neutralisation progressive des solutions réactionnelles. La pulvérisation régulière des vers par les mêmes solutions réactionnelles a permis de constater que plus le pH s’écarte de la neutralité, plus la variation du poids frais moyen des lots de vers est importante. Cette chute du poids frais des vers témoigne de la libération des excrétions cutanées sous l’effet du pH. Le pouvoir neutralisant est d’autant plus important que le poids frais des lots de vers est grand. L’application des excrétions cutanées seules entraine la neutralisation des solutions réactionnelles acides. Compte tenus de ces résultats, on peut dire que dans la nature, Lumbricus terrestris interviendrait directement sur le pH acide du sol par l’intermédiaire de ses excrétions cutanées.
This study attempts to reveal the role of Lumbricus terrestris in the regulation of pH. The experimental approach adopted will allow the removal of any possible confusion with soil components. In fact, immerging worms in reactional solutions with different acidic pH has permitted the delineation of an in vitro tolerance range contained between pH = 2 and pH = 7. In this range, the intensity of the reactions and the abundance of cutaneous excreta increase along with the deviation of the pH from the neutral zone. Thus, we can notice a trend to gradual neutralization of the reactional solutions. By spraying the worms regularly with those same acidic solutions showed that the higher the pH deviates from neutrality, the more significant the change of worm’s weight is. This drop in worm’s fresh weight proves the release of cutaneous excreta under the effect of pH. The neutralizing power is more important when the fresh weight of the worms is great. It is also essential to point out that applying the cutaneous excreta alone, causes the neutralization of acidic solutions. Holding account of these results, we can affirm that, in the nature, Lumbricus terrestris affects directly the soil’s pH by its cutaneous excreta.
L’étude du rôle de Lumbriscus terrestris dans la régulation du pH a suscité notre intérêt en raison de l’importance de ce facteur dans la fertilité du sol. Pour atteindre cet objectif, nous avons mis ...au point un nouveau protocole expérimental, entièrement réalisé en dehors du sol, afin d’écarter les interférences possibles sur la variation du pH. La procédure par immersion des vers dans des solutions réactionnelles à différents pH basiques a permis la délimitation d’une zone de tolérance in vitro comprise entre pH=7 et pH=12. Dans cette zone, plus le pH s’écarte de la neutralité, plus la réaction des vers est intense et plus la production des excrétions cutanées est abondante. On assiste instantanément à une tendance à la neutralisation progressive des solutions réactionnelles basiques. La procédure par pulvérisations régulières des vers par les mêmes solutions réactionnelles basiques a permis de constater que plus le pH s’écarte de la neutralité plus la diminution du poids frais moyen des vers est importante. Cette chute du poids frais confirme la libération des excrétions cutanées constatée de visu lors de la première procédure. Dans une autre expérience nous démontrons que l’effet neutralisant est fonction du poids frais des vers. En fin, l’application des excrétions cutanées isolées à partir des vers sur des solutions réactionnelles basiques entraine également une tendance à la neutralisation du pH de ces dernières. Compte tenu de ces résultats, on peut dire que dans la nature Lumbricus terrestris interviendrait directement par l’intermédiaire de ses excrétions cutanées dans la neutralisation des sols aux pH basiques.
Given that Lumbriscus terrestris represents an important factor in soil fertility, our interest was sparked to study its role in pH regulation. To achieve this purpose, we developed a new experimental protocol which is entirely realised outside the soil in order to exclude potential interferences that may affect the pH variation.We proceeded by immersing the worms in various reactional solutions having various levels of basic pH. This process allowed us to define a tolerance zone in vitro ranging between pH=7 and pH=12. In this tolerance area, the more the pH deviates from neutrality, the more the worms’ reaction is intense and the more the production of cutaneous excretions becomes abundant. Along with the production of these excretions, we instantly witness a trend towards the gradual neutralisation of the basic reactional solutions. By regularly spraying the worms with the same basic reactional solutions, we could notice that the average fresh weight of worms decreases significantly the more the pH deviates from neutrality. The fresh weight’s decrease confirms the release of cutaneous excretions observed during the first process. Another experiment of our study reveals that the neutralising effect is a function of the worms’ fresh weight. As a last experiment, we applied cutaneous excretions, previously isolated from worms, on basic reactional solutions. This process showed that the isolated excretions lead to a trend to the neutralisation of the basic reactional solutions.In light of these results, we can say that, in nature, Lumbricus terrestris intervenes directly through its cutaneous excretions in neutralizing soil having a basic pH.
Cette étude tente d’élucider le rôle de Lumbricus terrestris dans la régulation du pH. L’approche expérimentale adoptée permet d’écarter toutes les interférences possibles avec les composantes du ...sol. L’immersion des vers dans les solutions réactionnelles à différents pH acides a permis la délimitation in vitro d’une zone de tolérance comprise entre pH = 2 et pH = 7. Dans cette zone, plus le pH s’écarte de la neutralité plus la réaction des vers est intense et plus la production des excrétions cutanées est abondante. On assiste à une tendance à la neutralisation progressive des solutions réactionnelles. La pulvérisation régulière des vers par les mêmes solutions réactionnelles a permis de constater que plus le pH s’écarte de la neutralité, plus la variation du poids frais moyen des lots de vers est importante. Cette chute du poids frais des vers témoigne de la libération des excrétions cutanées sous l’effet du pH. Le pouvoir neutralisant est d’autant plus important que le poids frais des lots de vers est grand. L’application des excrétions cutanées seules entraine la neutralisation des solutions réactionnelles acides. Compte tenus de ces résultats, on peut dire que dans la nature, Lumbricus terrestris interviendrait directement sur le pH acide du sol par l’intermédiaire de ses excrétions cutanées.
This study attempts to reveal the role of Lumbricus terrestris in the regulation of pH. The experimental approach adopted will allow the removal of any possible confusion with soil components. In fact, immerging worms in reactional solutions with different acidic pH has permitted the delineation of an in vitro tolerance range contained between pH = 2 and pH = 7. In this range, the intensity of the reactions and the abundance of cutaneous excreta increase along with the deviation of the pH from the neutral zone. Thus, we can notice a trend to gradual neutralization of the reactional solutions. By spraying the worms regularly with those same acidic solutions showed that the higher the pH deviates from neutrality, the more significant the change of worm’s weight is. This drop in worm’s fresh weight proves the release of cutaneous excreta under the effect of pH. The neutralizing power is more important when the fresh weight of the worms is great. It is also essential to point out that applying the cutaneous excreta alone, causes the neutralization of acidic solutions. Holding account of these results, we can affirm that, in the nature, Lumbricus terrestris affects directly the soil’s pH by its cutaneous excreta.
L’étude du rôle de Lumbriscus terrestris dans la régulation du pH a suscité notre intérêt en raison de l’importance de ce facteur dans la fertilité du sol. Pour atteindre cet objectif, nous avons mis ...au point un nouveau protocole expérimental, entièrement réalisé en dehors du sol, afin d’écarter les interférences possibles sur la variation du pH. La procédure par immersion des vers dans des solutions réactionnelles à différents pH basiques a permis la délimitation d’une zone de tolérance in vitro comprise entre pH=7 et pH=12. Dans cette zone, plus le pH s’écarte de la neutralité, plus la réaction des vers est intense et plus la production des excrétions cutanées est abondante. On assiste instantanément à une tendance à la neutralisation progressive des solutions réactionnelles basiques. La procédure par pulvérisations régulières des vers par les mêmes solutions réactionnelles basiques a permis de constater que plus le pH s’écarte de la neutralité plus la diminution du poids frais moyen des vers est importante. Cette chute du poids frais confirme la libération des excrétions cutanées constatée de visu lors de la première procédure. Dans une autre expérience nous démontrons que l’effet neutralisant est fonction du poids frais des vers. En fin, l’application des excrétions cutanées isolées à partir des vers sur des solutions réactionnelles basiques entraine également une tendance à la neutralisation du pH de ces dernières. Compte tenu de ces résultats, on peut dire que dans la nature Lumbricus terrestris interviendrait directement par l’intermédiaire de ses excrétions cutanées dans la neutralisation des sols aux pH basiques.
Given that Lumbriscus terrestris represents an important factor in soil fertility, our interest was sparked to study its role in pH regulation. To achieve this purpose, we developed a new experimental protocol which is entirely realised outside the soil in order to exclude potential interferences that may affect the pH variation. We proceeded by immersing the worms in various reactional solutions having various levels of basic pH. This process allowed us to define a tolerance zone in vitro ranging between pH=7 and pH=12. In this tolerance area, the more the pH deviates from neutrality, the more the worms’ reaction is intense and the more the production of cutaneous excretions becomes abundant. Along with the production of these excretions, we instantly witness a trend towards the gradual neutralisation of the basic reactional solutions. By regularly spraying the worms with the same basic reactional solutions, we could notice that the average fresh weight of worms decreases significantly the more the pH deviates from neutrality. The fresh weight’s decrease confirms the release of cutaneous excretions observed during the first process. Another experiment of our study reveals that the neutralising effect is a function of the worms’ fresh weight. As a last experiment, we applied cutaneous excretions, previously isolated from worms, on basic reactional solutions. This process showed that the isolated excretions lead to a trend to the neutralisation of the basic reactional solutions. In light of these results, we can say that, in nature, Lumbricus terrestris intervenes directly through its cutaneous excretions in neutralizing soil having a basic pH.
La section de Lumbricus terrestris L. au niveau du 40e métamère, basée sur l'examen de la répartition des différents orifices excréteurs sur sa surface corporelle, a permis de déterminer les régions ...du corps réellement impliquées dans la production de substances rhizogènes. Les analyses spectrophotométriques et les tests biologiques effectués sur Phaseolus vulgaris L. à partir des extraits des parties antérieures et postérieures du ver ont révélé que ces deux parties interviennent dans la production des composés indoliques. Cette production serait cependant plus importante au niveau de la partie postérieure du ver s'étalant du 40e métamère jusqu'au pygidium. Ce résultat laisse supposer que seuls les orifices excréteurs communs à tous les métamères sont impliqués dans cette production. Les analyses chromatographiques et spectrophotométriques effectuées à partir des empreintes dorsales et ventrales des excrétions cutanées, récoltées directement sur des plaques chromatographiques à partir de vers de terre vivants, ont révélé la présence des composés indoliques basiques sur toute la longueur du ver, particulièrement au niveau des empreintes des orifices excréteurs cœlomiques et urinaires.
Determination of rhizogenous excretion area at Lumbricus terrestris L. The partition of the Lumbricus terrestris L., after the observation of different excretory orifices on its bodily surface at the 40th segment allowed to determine the body parts actually involved in the production of rhizogenous substances. Spectrophotometric analysis and biological tests conducted on Phaseolus vulgaris L. from worm's anterior and posterior extracts parts revealed that both parts participate in the production of indol-derived substances. However, this production may be more important at the level of the worm's posterior parts. It is therefore hypothesized that only those excretory orifices commun to all segments are involved in this production. Chromatographic and spectrophotometric analysis conducted on living worms from their dorsal and ventral prints of cutaneous excretions extracted directly from chromatographic plates, revealed the presence of basic indol-derived substances throughout the length of the worm, particularly at the level of coelomic and urinary excretory orifices.
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