Vegetation spatial heterogeneity in a hyper arid Biosphere Reserve area in north Africa

Ninety eight species of angiosperms belonging to 34 families were identified in the Wadi Allaqi Biosphere Reserve (S. E. Egypt): 33.7%annuals and 66.3%perennials. The members of Leguminosae contributed 19.4% of the total flora, considering the most dominant family inWadi Allaqi. Three herbaceous species were recorded for the first time in this region: Iphiona scabra, Chenopodium album and Lotus deserti. Eight vegetation clusters were obtained and categorized into 4 distinct groups according to soil composition and chemical characteristics (concentration of bicarbonates, calcium, magnesium and chlorides), and intensity of inundation by the water of Lake Nasser

Vegetation spatial heterogeneity in a hyper arid Biosphere Reserve area in north Africa

Ninety eight species of angiosperms belonging to 34 families were identified in the Wadi Allaqi Biosphere Reserve (S. E. Egypt): 33.7%annuals and 66.3%perennials. The members of Leguminosae contributed 19.4% of the total flora, considering the most dominant family inWadi Allaqi. Three herbaceous species were recorded for the first time in this region: Iphiona scabra, Chenopodium album and Lotus deserti. Eight vegetation clusters were obtained and categorized into 4 distinct groups according to soil composition and chemical characteristics (concentration of bicarbonates, calcium, magnesium and chlorides), and intensity of inundation by the water of Lake Nasser

Some observations on the plant communities of Dungul Oasis (Western Desert, Egypt)

During a visit to the Dungul Area (Western Desert, SW Egypt), several vegetation records were made. The number of species per plot (25 m2) was extremely low: mainly monospecific stands were found. A combination of two (or even three) species was reached either in the transition belts of herbaceous species or of one tree species with understory plants. Special attention was paid to the rare palm species Medemia argun, endemic to Nubia. A famous old specimen known from literature was encountered in dead state, but several living young specimens were observed

Some observations on the plant communities of Dungul Oasis (Western Desert, Egypt)

During a visit to the Dungul Area (Western Desert, SW Egypt), several vegetation records were made. The number of species per plot (25 m2) was extremely low: mainly monospecific stands were found. A combination of two (or even three) species was reached either in the transition belts of herbaceous species or of one tree species with understory plants. Special attention was paid to the rare palm species Medemia argun, endemic to Nubia. A famous old specimen known from literature was encountered in dead state, but several living young specimens were observed

Sadržaj toksičnih i esencijalnih metala u ljekovitom bilju koje raste u onečišćenim i neonečišćenim područjima u Makedoniji

The aim of this study was to determine and compare Ba, Cr, Cd, Fe, Sr, Pb, and Zn content in medicinal herbs Urtica dioica L., Taraxacum officinale, and Matricaria recutita growing in polluted and unpolluted areas of the Republic of Macedonia. The metal content was determined using inductively coupled plasma atomic emission spectroscopy (ICP-AES). In the unpolluted area of Mt. Plačkovica the metal content in Taraxacum officinale was in the descending order: Fe>Sr>Zn>Ba>Cr, while Pb and Cd were below the limit of detection. In the polluted area of Veles, the order was as follows: Fe>Zn>Sr>Pb>Ba>Cd>Cr. Our results suggest that quality assurance and monitoring of toxic metals is needed for plants intended for human use and consumption. Medicinal plants should be picked in areas free of any contamination sources.Cilj je ovoga istraživanja bio utvrditi i usporediti sadržaj Ba, Cr, Cd, Fe, Sr, Pb i Zn u ljekovitom bilju Urtica dioica L., Taraxacum offi cinale i Matricaria recutita koje raste u onečišćenome odnosno neonečišćenome području u Republici Makedoniji. Sadržaj metala utvrdili smo s pomoću atomske emisijske spektroskopije induktivno spregnutom plazmom (engl. inductively coupled plasma atomic emission spectroscopy, krat. ICP-AES). U neonečišćenome području planine Plačkovice, sadržaj metala u Taraxacum offi cinale kretao se kako slijedi: Fe>Sr>Zn>Ba>Cr, dok su Pb i Cd bili ispod granice detekcije. U onečišćenome području blizu talionice olova i cinka u Velesu redoslijed je bio ovakav: Fe>Zn>Sr>Pb>Ba>Cd>Cr. Naši rezultati upućuju na potrebu za osiguranjem kakvoće i praćenjem razina toksičnih metala u biljaka namijenjenih ljudskoj uporabi. Ljekovito bilje valja brati u područjima bez izvora onečišćenja

Vegetation clustering along irrigation and drainage canal banks in an extreme arid area in Upper Egyp

Vegetation analysis of the irrigation and drainage canals of the Aswan Province indicates the dominance of Pluchea dioscoridis, Phragmites australis, Cynodon dactylon, Imperata cylindrica, Alhagi graecorum, Sonchus oleraceus, Ceratophyllum demersum and Polypogon monspeliensis. The classification of stands according to the TWINSPAN technique resulted in seven vegetation clusters at level three. The seven clusters of level three are named after the dominant species as follows: (I) Sesbania sesban, (II) Chenopodium murale-Digitaria sanguinalis-Echinochloa colona, (III) Cyperus alopecuroides, (IV) Cynodon dactylon, (V) Phoenix dactylifera-Oxystelma alpini-Hyphaene thebiaca, (VI) Tamarix nilotica and (VII) Anagallis arvensis-Cuscuta pedicellata-Convolvulus arvensis-Chenopodium album. Among the estimated soil variables in the present study, sand, silt, Mg+2 and organic matter are important in characterising the vegetation clusters

Production processes of lipopeptides from Bacillus subtilis

L'influence des facteurs principe environnement dans le but d'optimiser la production des bioprocédés lipopeptide ont été testés en vue de son utilisation dans la conception nouvelle de bioréacteur à lit fluidisé inverse couplée à une section film de liquide dessus. La production de surfactine lipopeptides et fengycine a été réalisée par les cellules libres et immobilisées aérobie d'un nouveau dérivé spontanée Bacillus subtilis BBG21, qui est un mutant spontané de l'ATCC 21332 considérés comme de type sauvage. Les résultats ont été comparés à ceux obtenus avec la souche de type sauvage. Les principaux paramètres ont été testés: le taux de transfert d'oxygène, le pH et la température. Les souches ont été cultivées dans un milieu de Landy et Landy modifié de tampon MOPS avec 0,1 M. Influence du taux de transfert d'oxygène a été testé dans des flacons agités à l'aide de tailles de flacon différentes, le volume de remplissage, la fréquence d'agitation et de diamètre en secouant, la production de surfactine a montré une forte corrélation avec l'augmentation des taux de transfert d'oxygène, contrairement à la fengycine, tandis que le taux de transfert d'oxygène très diminué dû à l'acidification du milieu de culture grâce à l'absence de production de lipopeptides a été détecté. Trois régimes différents d’optimisation de la production de lipopeptides ont été observées avec un taux élevé, modéré et limité (OTR) et différents (Rsurf / feng). La meilleure productivité a été obtenue pour la culture à pH 7,0 initial. L'augmentation de la température a permis d'améliorer le rendement surfactine mais a réduit la production fengycine qui a été presque indétectable. Toutefois, l'optimisation de la production et le transfert d'oxygène de gaz-liquide et de mousse ont été étudiés dans un laboratoire dans le bioréacteur à lit inverse fluidisé de conception proposée avec une section film liquide dessus. L'oxygène coefficient de transfert volumétrique (kla) et l'activité mousse ont été déterminés à différentes conditions en utilisant le modèle et la fermentation réelle. Les niveaux de surfactant ont été examinés ci-dessous, et plus près de la concentration micellaire critique (CMC). Les valeurs des (kla) avec deux types de particules de différentes rugosité de surface ont été déterminées et pour une gamme de vitesses de liquide superficielle (Ul) de 0,01 à 0,05 m s-1, les vitesses des gaz (Ug) de 0,003 à 0,014 m s-1 et la surface tensions (σ) de 30 à 72 mN m-1. L'influence du support a été démontrée. Une forte réduction de ce paramètre a été observée dans le modèle et le réel et le media modèle quand la tension de surface a diminué de 72 à 30 mN m-1. Toutefois, la présence de surfactine et fengycine génère un moussage excessif qui impose des difficultés sur le rendement du bioréacteur qui était contrôlée par la conception proposée de nouveaux réacteurs. Les différentes gammes de vitesse spatiale du gaz minute, ainsi que l'état de non équilibre de régimes d'écoulements de fluides ont été étudiés. En utilisant l'approche de l'analyse de corrélation pour une dimension (kla) proposée et les coefficients calculés et expérimentaux sont en assez bon accord.The influences of principle environmental factors in the goal to optimize the lipopeptide production bioprocess were tested in view of its use in new design of inverse fluidized bed bioreactor coupled with a liquid film top section. The production of lipopeptides surfactin and fengycin was performed by free and immobilized aerobic cells of a new spontaneous derivative Bacillus subtilis BBG21, which is a spontaneous mutant of the ATCC 21332 considered as wild type. Results were compared to those obtained with the wild-type strain. The main parameters were tested: oxygen transfer rate, pH and temperature. The strains were cultivated in Landy and Landy modified medium buffered with MOPS 0.1 M. Influence of oxygen transfer rate was tested in shake flasks by using different flask size, filling volume, shaking frequency and shaking diameter, the surfactin production showed high correlation with the increasing of oxygen transfer rate, contrary with fengycin, while the highly decreased of the oxygen transfer rate due to acidification of the culture medium due to no production of lipopeptides was detected. Three different lipopeptides production optimization regimes were observed with high, moderate and limited (OTR) and different (Rsurf/feng) ratio. The best productivity was obtained for the culture at initial pH 7.0. Interestingly the increasing of temperature allowed to improve the surfactin yield but reduced the fengycin production which was nearly undetectable. However, the production optimization and the gas-liquid oxygen transfer and foaming were studied in a laboratory scale in the proposed bioreactor design inverse fluidized bed with a liquid film top section. The volumetric oxygen transfer coefficient (kla) and foaming activity were determined at various conditions using model and real fermentation. Surfactant levels were examined below, near and over the critical micelle concentration (CMC). The (kla) values with two types of different surface roughness particles were determined and for a range of superficial liquid velocities (Ul) from 0.01 to 0.05 m s-1, gas velocities (Ug) from 0.003 to 0.014 m s-1 and surface tensions (σ) from 30 to 72 mN m-1. The influence of support has been demonstrated. A strong reduction of this parameter has been observed in the real and model media when the surface tension decreased from 72 to 30 mN m-1. However, the presence of surfactin and fengycin generates extensive foaming that imposes difficulties on the bioreactor performance which was controlled by the proposed new reactor design. The different ranges of gas minute space velocity, as well as no steady state regimes of fluid flows have been studied. By using the dimensionless analysis approach a correlation for (kla) has been proposed and the calculated and experimental coefficients are in fairly good agreement