Papers by Mostafa Lamhamdi
Journal of microbiology, biotechnology and food sciences
Goat milk, a highly nutritious product is widely used in cheese making. In order to properly sele... more Goat milk, a highly nutritious product is widely used in cheese making. In order to properly select suitable milk samples for production, fifty-five samples of raw goat’s milk were collected from eight farms in the North-West of Morocco to analyze their counts of various mesophilic bacteria and determining the physicochemical characteristics during different seasons of the year. Lactic acid bacteria (LAB) were isolated, identified, and screened for several technological properties. Overall mean values for mesophilic aerobic flora were above 7.10 log cfu/mL in spring and 5.80 log cfu/mL during winter with a statistically significant difference found between all the microorganisms except for coagulase-positive staphylococci. The physical and chemical composition tests showed higher values for fat (4.9±1.01%), dry matter (13.98±0.95%), ash (1.3±0.12%), lactose (3.1±0.65 g/L), and protein (4.6±1.03 g/L) during the winter season which could be of great interest for cheese production. fat...
Comptes Rendus Biologies, 2011
Plant biology and pathology / Biologie et pathologie vé gé tales Lead phytotoxicity on wheat (Tri... more Plant biology and pathology / Biologie et pathologie vé gé tales Lead phytotoxicity on wheat (Triticum aestivum L.) seed germination and seedlings growth Phytotoxicite´du Plomb lors de la germination et la croissance du ble(Triticum aestivum L.
Plant Physiology and Biochemistry, 2016
20-Hydroxyecdysone (20E) is the most abundant phytoecdysteroid (PE) produced by plants, where it ... more 20-Hydroxyecdysone (20E) is the most abundant phytoecdysteroid (PE) produced by plants, where it represents a protective molecule against insect attack. The aim of the present study was to assess the effects of 20E on the growth, metabolic enzymes and antioxidant systems of wheat seedlings under lead stress induced by Pb(NO 3) 2 (3 mM). Pre-treatment concentrations (0, 1, 3 and 5 mM) of 20E were applied for two days, then wheat seedlings were transferred for 5 days to a treatment solution containing lead nitrate. When plants were grown without pre-treatment, germination and growth were impaired, while signs of oxidative stress were observed. 20E pre-treatment (3 or 5 mM) was able to efficiently protect seedlings from Pb toxicity by reducing Pb uptake and Pb-induced oxidative stress, as well by enhancing Pb excretion. Thus, 20E pre-treatment maintains normal germination, elongation, biomass, and metabolism in spite of the presence of Pb. Our results show that 20E protects oxidative balance and enhances the anti-oxidative systems, and more specifically the ascorbate-glutathione system. To our knowledge, this study shows for the first time that 20E treatment induces metabolic changes that allow the plants to resist heavy metal stress.
Saudi Journal of Biological Sciences, 2013
Lead (Pb) is the most common heavy metal contaminant in the environment. Pb is not an essential e... more Lead (Pb) is the most common heavy metal contaminant in the environment. Pb is not an essential element for plants, but they absorb it when it is present in their environment, especially in rural areas when the soil is polluted by automotive exhaust and in fields contaminated with fertilizers containing heavy metal impurities. To investigate lead effects on nutrient uptake and metabolism, two plant species, spinach (Spinacia oleracea) and wheat (Triticum aestivum), were grown under hydroponic conditions and stressed with lead nitrate, Pb(NO 3) 2 , at three concentrations (1.5, 3, and 15 mM). Lead is accumulated in a dose-dependent manner in both plant species, which results in reduced growth and lower uptake of all mineral ions tested. Total amounts and concentrations of most mineral ions (Na, K, Ca, P, Mg, Fe, Cu and Zn) are reduced, although Mn concentrations are increased, as its uptake is reduced less relative to the whole plant's growth. The deficiency of mineral nutrients correlates in a strong decrease in the contents of chlorophylls a and b and proline in both species, but these effects are less pronounced in spinach than in wheat. By contrast, the effects of lead on soluble proteins differ between species; they are reduced in wheat at all lead concentrations, whereas they are increased in spinach, where their value peaks at 3 mM Pb.
African Journal of Biotechnology, 2007
20-hydroxyecdysone (20E) is the major phytoecdysteroid of about 6% of plants. Its role in plant p... more 20-hydroxyecdysone (20E) is the major phytoecdysteroid of about 6% of plants. Its role in plant physiology has not been fully elucidated. In this work we studied the effects of 20E application on some morphological and biochemical parameters of tomato, Lycopersicum esculentum, seed during germination and seedling development (5 d). We compared the 20E effects with the action of phytohormones: gibberellic acid (GA 3), naftalen acetic acid (NAA), benzyl amino purine (BAP). NAA treatment resulted in marked reduction in shoot length. GA 3 treatment promoted maximal shoot elongation. BAP affected negatively shoot length only at late stages, while 20E application stimulated shoot elongation at early stages and reduced it on the fifth day; NAA inhibited root elongation all along the test period. GA 3 treatment had no effect on root length, whereas BAP showed strong inhibition on root elongation. On the other hand, 20E showed a weak inhibition of root elongation on the fifth day. As compared to control and to other treatments, NAA and 20E provoked a drastic decrease in protein contents during seedling growth, whereas a high increase was observed under BAP treatment. Electrophoresis revealed that protein bands were not degraded and mobilized after NAA treatment while in control or after 20E and others phytohormones applications, protein patters displayed weak band intensities and some of them were not detected. NAA, GA 3 and BAP provoked a decrease in proline content during seedlings, while the effect of 20E on proline levels varied during germination and plantlet development. This work showed that 20E like phytohormones fulfil some bioactive actions during germination and seedlings growth in tomato.
Plant Physiology and Biochemistry, 2016
20-Hydroxyecdysone (20E) is the most abundant phytoecdysteroid (PE) produced by plants, where it ... more 20-Hydroxyecdysone (20E) is the most abundant phytoecdysteroid (PE) produced by plants, where it represents a protective molecule against insect attack. The aim of the present study was to assess the effects of 20E on the growth, metabolic enzymes and antioxidant systems of wheat seedlings under lead stress induced by Pb(NO3)2 (3 mM). Pre-treatment concentrations (0, 1, 3 and 5 μM) of 20E were applied for two days, then wheat seedlings were transferred for 5 days to a treatment solution containing lead nitrate. When plants were grown without pre-treatment, germination and growth were impaired, while signs of oxidative stress were observed. 20E pre-treatment (3 or 5 μM) was able to efficiently protect seedlings from Pb toxicity by reducing Pb uptake and Pb-induced oxidative stress, as well by enhancing Pb excretion. Thus, 20E pre-treatment maintains normal germination, elongation, biomass, and metabolism in spite of the presence of Pb. Our results show that 20E protects oxidative bal...
Environmental science and pollution research international, 2013
Spinach extracts contain powerful natural antioxidants and have been used to improve the response... more Spinach extracts contain powerful natural antioxidants and have been used to improve the response of animal cells to various stress factors. The aim of the present study was to assess the effects of a methanolic extract of spinach (SE) used at two concentrations (21.7 and 217 ppm) on the growth, certain enzymes and antioxidant systems in wheat seedlings under lead stress. When wheat seedlings were grown for 7 days in a solution containing Pb(NO3)2 (3 mM), germination and growth were impaired, while signs of oxidative stress were observed. SE (217 ppm) pretreatment was able to protect seedlings from Pb toxicity by both reducing Pb uptake and Pb-induced oxidative stress. As a consequence, almost normal germination, elongation, biomass and α-amylase activity were restored by SE (217 ppm) pretreatment of wheat seedlings, in spite of the presence of Pb. Our results support the protective role and the antioxidant effect of SE against Pb. These results show an amazing similarity to the effects of SE in animals, which suggests that providing “nutraceuticals” to plants could improve their “health” status.
Lead (Pb) is the most common heavy metal contaminant in the environment. Pb is not an essential e... more Lead (Pb) is the most common heavy metal contaminant in the environment. Pb is not an essential element for plants, but they absorb it when it is present in their environment, especially in rural areas when the soil is polluted by automotive exhaust and in fields contaminated with fertilizers containing heavy metal impurities. To investigate lead effects on nutrient uptake and metabolism, two plant species, spinach (Spinacia oleracea) and wheat (Triticum aestivum), were grown under hydroponic conditions and stressed with lead nitrate, Pb(NO3)2, at three concentrations (1.5, 3, and 15 mM).
Lead is accumulated in a dose-dependent manner in both plant species, which results in reduced growth and lower uptake of all mineral ions tested. Total amounts and concentrations of most mineral ions (Na, K, Ca, P, Mg, Fe, Cu and Zn) are reduced, although Mn concentrations are increased, as its uptake is reduced less relative to the whole plant’s growth. The deficiency of mineral nutrients correlates in a strong decrease in the contents of chlorophylls a and b and proline in both species, but these effects are less pronounced in spinach than in wheat. By contrast, the effects of lead on soluble proteins differ between species; they are reduced in wheat at all lead concentrations, whereas they are increased in spinach, where their value peaks at 3 mM Pb.
The relative lead uptake by spinach and wheat, and the different susceptibility of these two species to lead treatment are discussed.
Dietary effects of harmine, a β-carboline alkaloid, on development, energy reserves and α-amylase activity of Plodia interpunctella Hübner (Lepidoptera: Pyralidae), Jan 2012
The physiological and developmental effects of harmine, a β-carboline alkaloid, on the insect pes... more The physiological and developmental effects of harmine, a β-carboline alkaloid, on the insect pest Plodia interpunctella have been analyzed. When added at the larval diet, harmine induced a strong reduction of larvae weight, cannibalism between larvae, in addition to significant mortality. On the other hand, it caused a remarkable development disruption, manifested by both delay and reduction of pupation and adult emergence. Using spectrophotometric assays, we have shown that harmine ingestion provoked a severe reduction in protein, glycogen and lipid contents. Beside, when larvae fed harmine, the activity of the digestive enzyme α-amylase was strongly reduced. In conclusion, our experiments clearly show the susceptibility of P. interpunctella to harmine ingestion revealing the potent bioinsecticidal effect of harmine.
Comptes rendus biologies, 2011
Lead (Pb) is an environmental pollutant extremely toxic to plants and other living organisms incl... more Lead (Pb) is an environmental pollutant extremely toxic to plants and other living organisms including humans. To assess Pb phytotoxicity, experiments focusing on germination of wheat seeds were germinated in a solution containing Pb (NO3)2 (0.05; 0.1; 0.5; 1 g/L) during 6 days. Lead accumulation in seedlings was positively correlated with the external concentrations, and negatively correlated with morphological parameters of plant growth. Lead increased lipid peroxidation, enhanced soluble protein concentrations and induced a significant accumulation of proline in roots. Esterase activity was enhanced in the presence of lead, whereas a-amylase activity was significantly inhibited. Antioxidant enzymes activities, such as, ascorbate peroxidase, peroxidase, superoxide dismutase, catalase and glutathione S-transferase were generally significantly increased in the presence of lead in a dose-dependent manner. The present results thus provide a model system to screen for natural compounds able to counteract the deleterious effects of lead.
Moroccan Journal of Biology (12-2010/N 6-7), Dec 2010
lipid peroxidation were studied in two species, spinach (Spinacia oleracea L.) and wheat (Triticu... more lipid peroxidation were studied in two species, spinach (Spinacia oleracea L.) and wheat (Triticum aestivum L.), grown under hydroponical conditions in the absence or in the presence of various concentrations (1.5, 3, and 15 mM) of lead nitrate. Leaves and roots of control and Pb-stressed plants were harvested after one month of germination. The Tolerance Index (T.I. – to be defined) measured on leaves and roots of both plants decreased with the increase of Pb concentrations. In every case, T.I. was significantly higher in spinach than in wheat. The activity of antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD)] was increased in leaves and roots by lead treatment in a dose-related manner, but this increase was reduced in roots with the highest Pb concentration. Ascorbate peroxidase (APX) activity increased in spinach, but remained unchanged in wheat. The relative increase in enzyme activities demonstrated that spinach is more tolerant to Pb than wheat. Lipid peroxidation was enhanced with all levels of Pb in stressed wheat, whereas in spinach it increased only with the highest Pb concentration. These results indicate that under Pb-stress spinach is more resistant than wheat, and the possible mechanisms of these differences are discussed.
by Bakrim, A., Lamhamdi, M., Sayah, F., Chibi, F., 2007
20-hydroxyecdysone (20E) is the major phytoecdysteroid of about 6% of plants. Its role in plant p... more 20-hydroxyecdysone (20E) is the major phytoecdysteroid of about 6% of plants. Its role in plant physiology has not been fully elucidated. In this work we studied the effects of 20E application on some morphological and biochemical parameters of tomato, Lycopersicum esculentum, seed during germination and seedling development (5 d). We compared the 20E effects with the action of phytohormones: gibberellic acid (GA 3), naftalen acetic acid (NAA), benzyl amino purine (BAP). NAA treatment resulted in marked reduction in shoot length. GA 3 treatment promoted maximal shoot elongation. BAP affected negatively shoot length only at late stages, while 20E application stimulated shoot elongation at early stages and reduced it on the fifth day; NAA inhibited root elongation all along the test period. GA 3 treatment had no effect on root length, whereas BAP showed strong inhibition on root elongation. On the other hand, 20E showed a weak inhibition of root elongation on the fifth day. As compared to control and to other treatments, NAA and 20E provoked a drastic decrease in protein contents during seedling growth, whereas a high increase was observed under BAP treatment. Electrophoresis revealed that protein bands were not degraded and mobilized after NAA treatment while in control or after 20E and others phytohormones applications, protein patters displayed weak band intensities and some of them were not detected. NAA, GA 3 and BAP provoked a decrease in proline content during seedlings, while the effect of 20E on proline levels varied during germination and plantlet development. This work showed that 20E like phytohormones fulfil some bioactive actions during germination and seedlings growth in tomato.
communication abstracts by Mostafa Lamhamdi
La 20 hydroxyecdyson (20E) est le composé majeur parmi les phytoecdysteroides accumulés dans les ... more La 20 hydroxyecdyson (20E) est le composé majeur parmi les phytoecdysteroides accumulés dans les plantes. L'effet de la 20E contre le stress biotique a été rapporté chez l'épinard Spinacia oleracea; la 20E a un rôle de défense contre les insectes phytophages et les nématodes du sol. Nous cherchons dans ce travail un effet de cette molécule lors d'un stress abiotique. Le traitement des grains de blé en germination in vitro par des concentration de plomb (0.3 et 0.6 g/L) inhibe le pouvoir germinatif des grains de blé. Nous avons trouvé que le Pb diminue l'activité amylase, enzyme clé dans le processus de germination, de façon dose dépendante. Le traitement combiné Pb-20E à des doses allant de 3 mM à 5 mM de 20E, conduit au rétablissement de l'activité amylasique de façon dose dépendante. Ce rétablissement est presque identique au témoin, dès que la concentration en 20E atteint 4mM. En effet, le dosage de l'amidon restant et des sucres solubles confirme le rôle inductif de la 20E à l'activité amylase ; nous avons trouvé une diminution de l'amidon restant dans les grains de blé après traitement combiné Pb-20E, en plus d'une augmentation de la teneur en sucres solubles. Tendis que lorsqu'on utilise le Pb seul on assiste à une faible teneur en sucres solubles et à une concentration élevée en amidon de réserve. Cette étude met en évidence un rôle de la 20E contre le stress causé par le Pb pendant la germination des grains de blé. D'autres expériences plus poussées avec d'autres biomarqueurs sont nécessaires pour affirmer que la 20E à un rôle protecteur contre le stress induit par le plomb.
Thesis Chapters by Mostafa Lamhamdi
The environmental degradation caused by the rapid expansion of the industrial activity has become... more The environmental degradation caused by the rapid expansion of the industrial activity has become the greatest threat to human existence and stability, since it reduces the productivity of agricultural land causing deterioration of profitability of crops yields. Lead (Pb) is one of the most common heavy metal contaminants in aquatic and terrestrial ecosystems. Lead affect plant process essentially due to its high affinity for biological molecules, the metal reacts with important functional groups in macromolecules which is the reason for the toxicity of Pb. Plant species behave differently in front of sensitivity to Pb , especially during the early stages of development, particularly during germination stage. Plants , being immobile, can suffer pollutionand that why some species have developed remarkable adaptations under various environmental stresses, including exposure to heavy metals.
Spinach (Spinacia oleracea), a plant used on heavy metals polluted soil remediation with the rhizofiltration procedure, was chosen to find the play role against Pb stress. This specie is one of the phytoecdysteroids (PEs) accumulators’ plants. The PEs are a family of molecules synthesized and accumulated by a wide variety of plant species, but rarely found in cultivated ones. These secondary metabolites are plants protects against phytophagous insects, playing a role of "hormonal disrupters". This work was conducted to identify potential targets and provide the crop germination resistance to Pb-stress.
In the first part we have studied various aspects of the responses of wheat (Triticum aestivum) during germination in the presence of Pb. The results showed that the uptake of Pb acts on seed viability and germination growth by generating oxidative stress and inhibiting energetic metabolism.
The second part of this work was designed to compare the phytotoxicity of Pb between wheat and spinach. This comparison showed a greater resistance in spinach than in wheat, and revealed an adaptive strategy in spinach involving two major factors: the resistance to oxidative stress and improved mineral nutrition.
Consequently, to understand this difference, the third part was carried out to establish and to test a new approach by performing an extract of organic compounds in the whole seedlings of spinach. We have shown that spinach extract was able to restore almost normal development to wheat seedlings, thanks to the combined reduction of lead uptake and stimulation of plant defenses against the oxidative stress. Further investigations are necessary in order to identify the chemicals responsible of these protective effects.
Finally, in the fourth part of this work, we have performed labeling experiments to test the 20-hydroxyecdysone (20E), PEs majority present in spinach, as a candidate involved in resistance to Pb stress. These works have shown that in wheat exposed to Pb, 20E restores the growth, metabolism, protects and maintains the oxidative balance.
The 20E is capable to protect wheat germination against Pb toxicity and represents an interesting protective molecule. On the other hand, this effect was also consistent with the role of spinach extract, and indeed explains partially his remarkable nutraceutical like effect. Furthermore, we can expect to explore more protective possibilities of 20E, with an aim to find if the 20E protects more generally against others environmental stresses.
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Papers by Mostafa Lamhamdi
Lead is accumulated in a dose-dependent manner in both plant species, which results in reduced growth and lower uptake of all mineral ions tested. Total amounts and concentrations of most mineral ions (Na, K, Ca, P, Mg, Fe, Cu and Zn) are reduced, although Mn concentrations are increased, as its uptake is reduced less relative to the whole plant’s growth. The deficiency of mineral nutrients correlates in a strong decrease in the contents of chlorophylls a and b and proline in both species, but these effects are less pronounced in spinach than in wheat. By contrast, the effects of lead on soluble proteins differ between species; they are reduced in wheat at all lead concentrations, whereas they are increased in spinach, where their value peaks at 3 mM Pb.
The relative lead uptake by spinach and wheat, and the different susceptibility of these two species to lead treatment are discussed.
communication abstracts by Mostafa Lamhamdi
Thesis Chapters by Mostafa Lamhamdi
Spinach (Spinacia oleracea), a plant used on heavy metals polluted soil remediation with the rhizofiltration procedure, was chosen to find the play role against Pb stress. This specie is one of the phytoecdysteroids (PEs) accumulators’ plants. The PEs are a family of molecules synthesized and accumulated by a wide variety of plant species, but rarely found in cultivated ones. These secondary metabolites are plants protects against phytophagous insects, playing a role of "hormonal disrupters". This work was conducted to identify potential targets and provide the crop germination resistance to Pb-stress.
In the first part we have studied various aspects of the responses of wheat (Triticum aestivum) during germination in the presence of Pb. The results showed that the uptake of Pb acts on seed viability and germination growth by generating oxidative stress and inhibiting energetic metabolism.
The second part of this work was designed to compare the phytotoxicity of Pb between wheat and spinach. This comparison showed a greater resistance in spinach than in wheat, and revealed an adaptive strategy in spinach involving two major factors: the resistance to oxidative stress and improved mineral nutrition.
Consequently, to understand this difference, the third part was carried out to establish and to test a new approach by performing an extract of organic compounds in the whole seedlings of spinach. We have shown that spinach extract was able to restore almost normal development to wheat seedlings, thanks to the combined reduction of lead uptake and stimulation of plant defenses against the oxidative stress. Further investigations are necessary in order to identify the chemicals responsible of these protective effects.
Finally, in the fourth part of this work, we have performed labeling experiments to test the 20-hydroxyecdysone (20E), PEs majority present in spinach, as a candidate involved in resistance to Pb stress. These works have shown that in wheat exposed to Pb, 20E restores the growth, metabolism, protects and maintains the oxidative balance.
The 20E is capable to protect wheat germination against Pb toxicity and represents an interesting protective molecule. On the other hand, this effect was also consistent with the role of spinach extract, and indeed explains partially his remarkable nutraceutical like effect. Furthermore, we can expect to explore more protective possibilities of 20E, with an aim to find if the 20E protects more generally against others environmental stresses.
Lead is accumulated in a dose-dependent manner in both plant species, which results in reduced growth and lower uptake of all mineral ions tested. Total amounts and concentrations of most mineral ions (Na, K, Ca, P, Mg, Fe, Cu and Zn) are reduced, although Mn concentrations are increased, as its uptake is reduced less relative to the whole plant’s growth. The deficiency of mineral nutrients correlates in a strong decrease in the contents of chlorophylls a and b and proline in both species, but these effects are less pronounced in spinach than in wheat. By contrast, the effects of lead on soluble proteins differ between species; they are reduced in wheat at all lead concentrations, whereas they are increased in spinach, where their value peaks at 3 mM Pb.
The relative lead uptake by spinach and wheat, and the different susceptibility of these two species to lead treatment are discussed.
Spinach (Spinacia oleracea), a plant used on heavy metals polluted soil remediation with the rhizofiltration procedure, was chosen to find the play role against Pb stress. This specie is one of the phytoecdysteroids (PEs) accumulators’ plants. The PEs are a family of molecules synthesized and accumulated by a wide variety of plant species, but rarely found in cultivated ones. These secondary metabolites are plants protects against phytophagous insects, playing a role of "hormonal disrupters". This work was conducted to identify potential targets and provide the crop germination resistance to Pb-stress.
In the first part we have studied various aspects of the responses of wheat (Triticum aestivum) during germination in the presence of Pb. The results showed that the uptake of Pb acts on seed viability and germination growth by generating oxidative stress and inhibiting energetic metabolism.
The second part of this work was designed to compare the phytotoxicity of Pb between wheat and spinach. This comparison showed a greater resistance in spinach than in wheat, and revealed an adaptive strategy in spinach involving two major factors: the resistance to oxidative stress and improved mineral nutrition.
Consequently, to understand this difference, the third part was carried out to establish and to test a new approach by performing an extract of organic compounds in the whole seedlings of spinach. We have shown that spinach extract was able to restore almost normal development to wheat seedlings, thanks to the combined reduction of lead uptake and stimulation of plant defenses against the oxidative stress. Further investigations are necessary in order to identify the chemicals responsible of these protective effects.
Finally, in the fourth part of this work, we have performed labeling experiments to test the 20-hydroxyecdysone (20E), PEs majority present in spinach, as a candidate involved in resistance to Pb stress. These works have shown that in wheat exposed to Pb, 20E restores the growth, metabolism, protects and maintains the oxidative balance.
The 20E is capable to protect wheat germination against Pb toxicity and represents an interesting protective molecule. On the other hand, this effect was also consistent with the role of spinach extract, and indeed explains partially his remarkable nutraceutical like effect. Furthermore, we can expect to explore more protective possibilities of 20E, with an aim to find if the 20E protects more generally against others environmental stresses.