CHARACTERIZATION AND BIOCONTROL POTENT OF STREPTOMYCES SP. ISOLATED FROM THE RHIZOSPHERE OF ONONIS ANGUSTISSIMA LAM.

A total of 40 actinomycetes isolated from rhizosphere soils of Ononis angustissima Lam. were in vitro tested for their antagonism against deferent pathogenic microorganisms by streak assay. Among the isolates, four (21, 2A26, 1B10 and 2C34) present a potent antagonism against both pathogenic bacteria and fungi, they were selected, identified by 16S rDNA sequence analysis and phenotypic properties, and tested for their antimicrobial activity as well as their biocontrol potential against Chickpea (Cicer arietinum L.) pathogenic fungus (Fusarium oxysporum). Cultural characteristic studies strongly suggested that these strains belong to the genus Streptomyces. The four Streptomyces sp., solubilize phosphate and produce extracellular fungal cell-wall degrading enzymes chitinase and protease, as well as a marked production of acid-ß-indole acetic (AIA). The nucleotide sequence of the 16S rRNA gene of Streptomyces sp. strains 21, 2A26, 1B10 and 2C34 exhibited close similarity (62-75%) with Streptomyces parvulus MARS 16S rRNA genes. The inhibition was higher against fungi and Gram+ bacteria, while Gram- bacteria were less inhibited. The growth of the plant pathogenic fungus Fusarium oxysporum was considerably inhibited in the presence of the strains 21, 2A26, 1B10 and 2C34 culture supernatant. These studies revealed that the presence of the Streptomyces strains in the soil significantly promoted the growth of the Chickpea plants. These results indicate that the Streptomyces strains isolated for rhizosphere from Ononis angustissima Lam. growing in arid conditions in southern Algeria (Sahara) could be an interesting source for antimicrobial bioactive substances and as biocontrol agents.

A PLAUSIBLE ROLE FOR POLLEN-RESIDING MOLDS IN AGRICULTURAL PURPOSES.

Pollen microbial content of 15 samples was investigated. Pollen was collected by honeybees. Total aerobic mesophilic count ranged from 3.00 to 5.48 Log CFU/g. Total mold and yeast count ranged from 2.3 to 6.99 Log CFU/g. Selected strains of isolated molds from pollen samples were characterized by conventional methods. Potent phytopathogenic and food spoilage species such as Penicillium sp., Alternaria alternata, Alternaria sp., Cladosporium werneckii, Mucor hiemalis, Rhizomucor pusillus, Aspergillus flavus, Aspergillus niger, Drechslera tritici-repentis, Verticillium albo-atrum, and Aspergillus alliaceus were recovered. Other fungal species with valuable biotechnological and plant diseases control purposes were isolated. They were characterized as Geotrichum candidum, Monilia sitophilia, and Sepedonium chrysospermum. Animal pathogenic molds were also isolated. Bee pollen may be considered as a source for a highly diverse fungal flora with different applications.

Endophytic fungi isolated from Pinus halepensis needles in M'sila (Algeria) region and their bioactivities.

Fungal endophytes grow asymptomatically within the tissues of all vascular plants and some are known to provide their host plants with tolerance to different types of environmental stress. Endophytic fungi were detected, isolated and collected from healthy needles of Alep pine (Pinus halepensis Mill.) from the canton of El-Haourane in M'sila, Algeria. For the author's knowledge, these fungi are reported from this conifer for the first time in this region. A survey has been conducted using randomly sampled needles of symptomless trees for two categories of needles (old and young). From 600 surface-sterilized needles collected from 15 trees (300 needles for each age), 29 fungal isolates were obtained and identified on the basis of the morphological characterization using microscopic observations. The fungal isolates were grouped in Deuteromycetes and Zygomycetes. Species of Moniliales were the most common fungi assaciated with P. halepensis. It appears from the results also that the colonization frequency (CF%) was dependant on the age of the needles; older needles were more densely colonized than the younger needles with a 68.5%. The results of this study indicate that P. halepensis serves as a host to numerous endophytic fungi. These fungi could have significance as a source of novel metabolites. And therefore the mycoendophytes genera of Penicillium, Acremonium, Aspergillus, Rhizopus, Trichosporon, Cladosporium, Fusarium, Trichoderma. Expressed an antagonistic and antibiotic effect against pathogenic microorganisms to humans and plants.

Evaluation of the toxicity of cypermethrin pesticide on organs weight loss and some biochemical and histological parameters.

An increase in global food demand has resulted in a significant increase in the use of pesticides in agriculture. Synthetic pyrethroid pesticides account for over 30% of the global pesticide use; Pyrethroid pesticides were used preferably over organochlorines and organophosphates due to their high effectiveness, low toxicity to non-target organisms and easy biodegrability. It has widespread applications in agriculture through the world and as well in Algeria. Cypermethrin is one of the most insecticidal pyrethroids widely used in agriculture regions of Setif. to control wide range of insect pests in a variety of crops. The aim of this study is to investigate the effects of cypermethrin (Cyper-Ac 271 g/l from the active substance of the cypermethrin) on hematological, biochemical parameters, body weight loss, and histopathological study of some organs. Male mice weighing 30-40g were used, separated in 5 groups, n=6, two groups controls given vehicle (oil vegetable) and three experimental groups (Cypermetherin and vegetable oil). The animals were gavaged by 1/5 LD50 (LD50 = 485 mg/kg b/w) for 2 and 4 weeks respectively, and with 1/20 LD50 for 12 weeks, then the animals sacrificed at the end of the experiment.. Blood was collected. Enzyme activities were assayed in the plasma samples obtained. Glutamate oxaloacetate transaminase (GOT), Glutamate pyruvate transaminase (GPT), Alkaline phosphatase (ALPH) and Glucose. Red blood cells, (RBC), and white blood cells (WBC) were calculated too. The samples of liver and kidney were processed for histology. The results indicated a significant increase in transaminases GOT, GPT, and AlP. The decrease in Hb, RBC and WBC which are related to the immunity, this is probably due to cell lyses explain the effect of Cypermetherin on erythropoeisis. cypermethrin treatment exhibited severe histopathological changes, especially in the liver and kideney accompanied by weight loss of some organs. We conclude that cypermethrin induces oxidative stress and modifies biochemical parameters and histological aspects of liver and kidney.

Biochemical, hematological and histological parameters induced by cypermetherin toxicity in domestic rabbits.

Cypermetherin is widely used in Algeria; this insecticide belongs to the group of pyrethroids classified by the World Health Organization as moderately harmful class II (WHO, 2005). This study was conducted to search the effect of non lethal dose on biochemical parameters, hematological and histological parts of the organs. Male of domestic rabbits Oryctolagus cuniculus (1 kg) received per week and per gavage 1/10 LD50 of Cypermetherin (ARRIVO 25%, active substance of Cypermetherin 250 g/l). blood was collected 72 hours after the treatment. Enzyme activities were assayed in the plasma samples for Glutamate oxalo acetate transaminase (GOT), Glutamate pyruvate transaminase (GPT), Alcaline phosphatase (AlcP), creatinine (Crea) and glucose. Red blood (RBC) cells and white blood cells (WBC) were calculated too. The results indicated a significant increase in transaminases GOT and GPT, and AlcP explain a high energy generating product and dysfunction of the liver. A decline in Crea, Hb, RBC and WBC which is related to the immunity, this is probably due to cell lyses explain the effect of Cypermetherin on erythropoeisis. Histological examination confirmed the biochemical tests by the observation of inflammatory infiltrate and perilobular fibrosis. In conclusion, Cypermetherin with used dose affects biochemical, hematological and histological parameters of the rabbits.

Cypermetherin toxic effects on spermatogenesis and male mouse reproductive organs.

Cypermetherin has been implicated in the development of a variety of reproductive disorders in humans and infertility in wild life, where it increases the death rate of the offspring and induces aggressiveness (Elbetieha et al., 2001). Studies in workers exposed to handling of agro pesticides indicate that they have defects in their reproduction capabilities characterized by infertility and/or a decrease in the fertilizing potential, fetal death. In this study, mice weighing 30-35 g were used, separated in 3 groups, (1) control (2) vehicle (oil) and (3) experimental (Cypermetherin and oil). The animals were gavaged by 1/5, 1/20 LD50 for 2 and 4 weeks respectively, and with 1/5 LD50 for 12 weeks, then sacrificed. Epididymal spermatozoa were evaluated with respect to quantity, motility and morphology. The histology of testis and epididymis was also studied. Sperm count decreased by around 20% in treated animals compared with control. Teratology observations showed a clear modification of sperm morphology, especially the flagella. Testicular and epididymal morphology was also impaired. It is concluded that Cypermetherin may cause morphological and functional alteration of the male reproductive tract.

Toxico-pathological effects in rats induced by lambda-cyhalothrin.

Pesticides are widely used chemicals making human exposure to pesticides a realistic possibility. Biomonitoring is a common and useful tool for assessing human exposure to pesticides. Pyrethroids are effective insecticides that are often used in household sprays, aerosol bombs, insect repellents, pet shampoos, and lice treatments. Using products containing these compounds will expose people to these chemicals. Since these compounds frequently are used on crOPs, they are often detected in fruits and vegetables. Biomonitoring of exposure is a useful tool for assessing exposure to pesticides. Biomonitoring involves the measurement of the parent pesticide, its metabolite or reaction product in biological media, typically blood or urine, to determine if an exposure has occurred and the extent of that exposure. Although not without its limitations, biomonitoring has great utility in integrating all routes of exposure allowing for one exposure measurement. Pesticides have much shorter environmental half-lives and tend not to bioaccumulate. In fact, from humans within 24 hr as the parent pesticide, a mercapturic acid detoxification product, oxidative or dealkylation metabolites, and/or glucuronide or sulphate-bound metabolites. However, because of the heavy agricultural and residential use of these chemicals, humans are continually exposed to many of these chemicals. The objective of the present study was to explore modification in toxico-pathological responses of rats treated with lambda-cyhalothrin (commercially called karate). Rats (250 g weight), were gavaged by 1/100 LD50 for 4 weeks (one dose every week). Blood was collected before dosing and after 48 hours from the treatment. Enzyme activities were assayed in the plasma samples obtained. Glutamate oxaloacetate transaminase (GOT), Glutamate pyruvate transaminase (GPT), Alkaline phosphatase (ALPH) and Glucose. The results showed a decrease in RBC; WBC and Hb. This probably explained by the effect of lambda cyhalothrin on the erythropoiesis and the destruction of cells. An increase of plasma enzyme activities in GOT and GPT were recorded, explain a high energy-generating product. The histopathological results showed alteration on the target organs such as liver and kidney, these biochemical and histological modifications are probably due to the effect of lambda cyhalothrin or their metabolites.

Biochemical investigation of cypermethrin toxicity in rabbits.

Pyrethroids are the most frequently used pesticides in agriculture, forestry, horticulture, hospitals public health, homes and textile industry. Cypermethrin, a composite pyrethroid is moderately toxic to mammals. Exposure to the pyrethroids occurs by inhalation, dermal and oral routes both accidentally as well as from the environment. Cypermethrin and DDT have been detected in human breast milk from malaria endemic area in South Africa. The WHO has recommended that the level of permethrin in drinking water not exceed 20 micrograms per liter (microg/L). The effects of exposure to any hazardous substance depend on the dose, the duration, how you are exposed, personal traits, habits and whether other chemicals are present. Pyrethroids are often combined commercially with other chemicals called synergists, which enhance the insecticidal activity of the pyrethrins and pyrethroids. The synergists prevent some enzymes from breaking down the pyrethrins and pyrethroids, thus increasing their toxicity. Because these compounds are broken down in the body quickly, there are several ways to measure the metabolites of these chemicals in human blood and urine. In this study the pyrethroid cypermethrin Sherpa 25% (active substance 250 g/l cypermethrin) was used, rabbits (1 kg weight), were gavaged by 1/20 LD50 for 3 weeks (one dose every week). Blood was collected before dosing and after 24, 72, 144 hours after the treatment. Enzyme activities were assayed in the plasma samples obtained. GOT, GPT, ALPH, CREA, GGT, Glucose and Total Pro were measured. Rabbits showed depression, decrease in feed intake, body weight and loose faeces. Livers exhibited fatty change, necrosis, lesions in kidney included tubular necrosis and pink homogeneous tubular casts. Serum ALT and creatinine concentrations increased while those of total proteins, albumin, serum cholesterol and triglycerides decreased.The results showed a decrease in RBC; WBC and Hb. This probably explained by the effect of cypermethrin on the erythropoiesis. An increase of plasma enzyme activities in GOT, GPT and CPK were recorded, explain a high energy-generating product. An increase, in the plasma enzyme activity in Alkaline phosphatase, related to their role in the cell permeability. The histopathological results showed lesions and morphological changes of hepato-cellular, fibrosis and appearance of inflammatory infiltrate, confirmed disturbances of the biochemical parameters. These changes were much underlines during the animal toxicity.

Characterization of Pseudomonas pathovars isolated from rosaceous fruit trees in East Algeria.

A survey of bacterial diseases due to Pseudomonas on rosaceous fruit trees was conducted. In forty two orchards located in the Constantine region ( East Algeria). Pseudomonas isolates were identified on the bases of their cultural and biochemical characteristics . A total of fifty nine phytopathogenic bacteria were isolated from diseased pome and stone fruit trees. Thirty one strains comparable to Pseudomonas syringae pv. syringae were isolated from cherry (Prunus avium L.), plum (P. domestica L.), apricot (P. armeniaca L.), almond (P. dulcis L.) and pear trees (Pirus communis L.); sixteen strains comparable to Pseudomonas syringae pv. morsprunorum were obtained from samples of cherry and plum. Twelve strains of Pseudomonas viridiflava were isolated from cherry, apricot and peach (Prunus persica L.).

Effects of nutritional factors on production of tabtoxin, a phytotoxin, by Pseudomonas syringae pv. tabaci.

Pseudomonas syringae pv. tabaci, the causal agent of the wildfire of tobacco, produces the phytotoxin tabtoxin. The effects of carbon, nitrogen sources and amino acids on growth and tabtoxin production by pv. tabaci, were examined by varying the components of a defined basal medium, which contained the following nutrients per liter: sucrose (10 g), KNO3 (5 g), MgSO(4).7H2O (0.2 g), CaCl(2).2H2O (0.11 g), FeSO(4).7H2O (20 mg), NaH2PO(4).2H2O (0.9 g) and H2PO(4).3HO (1 g). Bacterial growth was determined by cell density, and tabtoxin production was measured by the E. coli bioassay technique. Both growth and quantity of tabtoxin synthesized were significantly affected by carbon source, nitrogen source and amino acid supplements. Sorbitol, xylose and sucrose proved to be the best carbon sources for tabtoxin production. Specific toxin production was very low using glucose as a single carbohydrate source, although bacterial growth was well supported by glucose. Amount and type of nitrogen sources (NH4Cl or KNO3) affected the growth of pv. tabaci and quantities of tabtoxin produced. Nitrate was the best of these two forms of nitrogen for production of tabtoxin. Adding threonine to pv. tabaci grown in batch culture decreased the amount of tabtoxin production. Similar results were obtained with lysine, whereas, serine had no effects on quantities of tabtoxin production. The results of the present study were to formulate a medium which allowed for enhanced tabtoxin production by Pseudomonas syringae pv. tabaci.

The physiological development of the chlorotic lesion induced by coronatine.

Toxins are secondary metabolites produced by several plant pathogenic microorganisms. These toxins play a major role in the development of disease symptoms. Coronatine, the non specific toxin, was extracted and purified from the culture medium of Pseudomonas syringae pv. glycinea. In this study, the effect of coronatine on the development of the chlorotic lesion on the Phaseolus vulgaris L. leaves, indicates that coronatine induced chlorosis on treated leaves as well as or untreated leaves on the same plant. An other effect of this toxin is the reduction of amount of both chlorophyll a and b. These results, provide that the development of chlorotic lesion is a primarily mode of action of coronatine.