Spatial Distribution and Temporal Trends of Polycyclic Aromatic Hydrocarbons (PAHs) in Sediments from Lake Maryut, Alexandria, Egypt

Surface and core sediments from Lake Maryut, Egypt, one of the most polluted lakes in Egypt, were analyzed for polycyclic aromatic hydrocarbons (PAHs) using gas chromatography?Cmass spectrometry. This investigation represents the first extensive study of the distribution and sources of PAHs in sediments from Lake Maryut. The total PAHs concentrations (sum of 39 PAH compounds) in surface sediments varied greatly depending on the sampling location and ranged from 106 to 57,800 ng/g dry weight with a mean concentration of 6,950 ng/g. The most polluted areas are distributed in areas which are mainly influenced by municipal sewage and industrial effluent discharges, suggesting a direct influence of these sources on the pollutant distribution patterns. PAH concentrations were one to two orders of magnitude higher in comparison with those reported for riverine/estuaries systems around the world. Molecular indices, such as pyrogenic index (PI), methylphenanthrenes to phenanthrene ratio, HMW_PAH/LMW_PAH, A-PAHs/P-PAHs, FL/FL?+?PY, BaP/BaP?+?C, IP/IP?+?BgP, and Per/??(penta-aromatics) were calculated to evaluate different hydrocarbon origins and their relative importance. In general, sediments from the main basin and northwest basin of Lake Maryut showed the highest PAH concentrations with petrogenic signatures, indicating major sources of petrogenic PAHs in the city. On the other hand, lower levels of PAHs with a pyrogenic signature were widely recorded in areas that are distant from anthropogenic sources. At other locations, both petrogenic and pyrogenic inputs were significant. The concentrations of perylene relative to the penta-aromatic isomers are dominant especially in locations associated with terrestrial inputs and in the deepest core sediments, indicating diagenetic origin for the presence of perylene. Temporal trends of PAH concentrations in both cores sediments were influenced by input pathways and followed the economic development and the environmental policies of the Egyptian Government in the last 15 years. Finally, PAH levels in sediments were compared with Sediments Quality Guidelines (effects range median?Ceffects range low) for evaluation probable toxic effects on organism. Results suggest an ecotoxicological risk for benthic organisms mainly in the main basin area, where high concentrations of PAHs were found in sediments influenced by anthropogenic activities.     

Evaluation of the antigen relatedness and efficacy of a single vaccination with different infectious bronchitis virus strains against a challenge with Malaysian variant and QX-like IBV strains

BackgroundThe predominant infectious bronchitis virus (IBV) strains detected in chickens in Malaysia are the Malaysian variant (MV) and QX-like, which are associated with respiratory distress, nephropathy, and high mortality. On the other hand, the antigenic relatedness and efficacy of IBV vaccines against these 2 field IBV strains are not well characterized.ObjectivesThis study aimed to determine the antigen relatedness and efficacy of different IB vaccine strains against a challenge with MV and QX-like strains.MethodsThe antigen relatedness and the ability of different IB vaccine strains in conferring protection against MV and QX-like were assessed based on the clinical signs, macroscopic lesions, and ciliary activity.ResultsThe MV strain IBS037A/2014 showed minor antigenic subtype differences with the vaccine virus Mass H120 and 4/91 strains but showed major antigenic subtype differences with the K2 strain. The Malaysian QX-like strain IBS130/2015 showed major antigenic subtype differences with the MV strain IBS037A/2014 and the vaccine strains except for K2. Chickens vaccinated once with Mass (H120) or with non-Mass (4/91 and K2) developed antibody responses with the highest antibody titer detected in the groups vaccinated with H120 and 4/91. The mean ciliary activities of the vaccinated chickens were between 56 to 59% and 48 to 52% in chickens challenged with IBS037A/2014 and IBS130/2015, respectively. The vaccinated and challenged birds showed mild to severe lesions in the lungs and kidneys.ConclusionsDespite the minor antigenic subtype differences, a single inoculation with Mass or non-Mass vaccines could not protect against the MV IBS037A/2014 and QX-like IBS130/2015.     

A New Micromonospora Strain with Antibiotic Activity Isolated from the Microbiome of a Mid-Atlantic Deep-Sea Sponge

To tackle the growing problem of antibiotic resistance, it is essential to identify new bioactive compounds that are effective against resistant microbes and safe to use. Natural products and their derivatives are, and will continue to be, an important source of these molecules. Sea sponges harbour a diverse microbiome that co-exists with the sponge, and these bacterial communities produce a rich array of bioactive metabolites for protection and resource competition. For these reasons, the sponge microbiota constitutes a potential source of clinically relevant natural products. To date, efforts in bioprospecting for these compounds have focused predominantly on sponge specimens isolated from shallow water, with much still to be learned about samples from the deep sea. Here we report the isolation of a new Micromonospora strain, designated 28ISP2-46^T, recovered from the microbiome of a mid-Atlantic deep-sea sponge. Whole-genome sequencing reveals the capacity of this bacterium to produce a diverse array of natural products, including kosinostatin and isoquinocycline B, which exhibit both antibiotic and antitumour properties. Both compounds were isolated from 28ISP2-46^T fermentation broths and were found to be effective against a plethora of multidrug-resistant clinical isolates. This study suggests that the marine production of isoquinocyclines may be more widespread than previously supposed and demonstrates the value of targeting the deep-sea sponge microbiome as a source of novel microbial life with exploitable biosynthetic potential.     

Mode of inheritance of zinc accumulation in maize

The present study was undertaken to investigate the genetic nature of zinc (Zn) accumulation in the ear‐leaves of maize (Zea mays L.) plants. Fourteen inbred lines were evaluated. Out of which, five inbreds were chosen, two high Zn accumulators (Rg‐5 and Rd‐2), two low Zn accumulators (Rg‐8 and G‐307) and a moderate one (K‐64). These five parental inbreds were utilized to obtain all possible ten F1 hybrids (in one direction), 10 F2, 10 Bl, and 10 B2. All genotypes were planted and Zn was estimated at 50% tasseling stage. Zinc accumulation in the present genotypes was found to be genetically controlled and affected by additive genes. Significant values were obtained for the General Combining Abilities (GCA) but not for the Specific Combining Abilities (SCA) and the high Zn accumulating parents were the best general combiners. Four genes were found to be the minimum segregating factors in the (high x low) crosses for Zn accumulation.     

Changes in growth and nitrogen assimilation in barley seedlings under cadmium stress

Barley (Hordeum vulgare L. cv. Martin) plants grown in solution culture, were exposed to increasing cadmium (Cd) concentration (0, 5, 10, 25, 50, and 100 μM) for a duration of 12 days. The sequence of important biochemical steps of nitrate (NO₃) assimilation were studied in roots and shoots as a function of external Cd concentration. Cadmium uptake in roots and shoots increased gradually with Cd concentration in the medium. This Cd accumulation lowered substantially root and shoot biomass. The nitrate reductase (NR, EC 1.6.6.1) and nitrite reductase (NiR, EC 1.6.6.4) activities declined under Cd stress. Concurrently, tissue NO₃ contents and xylem sap NO₃ concentration were also decreased in Cd‐treated plants. These results suggest that Cd could exert an inhibitory effect on the assimilatory NO₃ reducing system (NR and NiR) through a restriction of NO₃ availability in the tissues. We therefore examined, in short‐term experiments (12 h), the impact of Cd on NO₃ uptake and the two reductases in nitrogen (N)‐starved plants that were pretreated or not with Cd. It was found that Cd induced inhibition of both NO₃ uptake and activities of NR and NiR, during NO₃ induction period. The possible mechanisms of Cd action on NO₃ uptake are proposed. Further, in Cd‐grown plants, the glutamine synthetase (GS, EC 6.3.1.2) showed a decreasing activity both in shoots and roots. However, increasing external Cd concentration resulted in a marked enhancement of glutamate dehydrogenase (NADH‐GDH, EC 1.4.1.2) activity, coupled with elevated levels of ammonium (NH₄ in tissues. On the other hand, the total protein content in Cd‐treated plants declined with a progressive and substantial increase of protease activity in the tissues. These findings indicate that under Cd stress the usual pathway of NH₄ assimilation (glutamine synthetase/glutamate synthase) can switch to an alternative one (glutamate dehydrogenase). The changes in all parameters investigated were concentration‐dependent and more marked in roots than shoots. The regulation of N absorption and assimilation by Cd in relation to growth and adaptation to stress conditions are discussed.     

Mycorrhizai associations with some plant species in a soil strip of different successional stages in Egypt

In this study, soil and plant samples were collected from a strip of soil comprising four successional stages from the eastern desert plateau to the Nile Valley, Egypt. On one hand, some essential elements [i.e., potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S)] and water contents decreased on transition from the desert soil to the Nile Valley. Soil nitrite content was the highest in Nile Valley soil and decreased toward desert soil. pH values of the soils did not strongly differ and were moderately alkaline. Root colonization with arbuscular‐mycorrhizae (AM) fungi of 33 plant species (11 cultivated and 22 wild) collected from the study area was highest in eastern desert plateau and decreased toward the Nile Valley. Mycorrhizai spore counts reflected the root colonization data. The decrease in mycorrhizai colonization was explained on the basis of difference in soil porosity, soil water contents, and toxicity of nitrite. Contents of K, Ca or Mg in some species were increased by increasing the colonization percentage of roots by AM fungi. Increasing the infection percentage of roots decreased or maintained the ratio of Na K+Ca+Mg (in meq) in the shoots of investigated plants. The contents of chlorophyll, soluble sugars, and protein significantly increased as a result of increasing colonization value. Also, mycorrhizal root colonization improved the water status of most plant species. These results suggest that increasing infection by AM fungi in the newly reclaimed soil may enable the plants to maintains its internal water status and mineral balance through decreasing the ratio of distressing ions to the nutrient ones.     

ALLEVIATING THE INFERTILITY OF AN ACID SULPHATE SOIL BY USING GROUND BASALT WITH OR WITHOUT LIME AND ORGANIC FERTILIZER UNDER SUBMERGED CONDITIONS

A study was conducted into the alleviation of the infertility of an acid sulphate by using ground basalt with or without ground magnesium limestone (GML) and organic fertilizer. Fresh soils were treated with the amendments and subjected to two cycles of submergence and drying. The soil was dominated by kaolinite, mica and smectite. The untreated soil pH was <3·5 and solution Al was high. GML application at 4 t ha⁻¹ was able to increase pH and subsequently reduced Al toxicity sufficiently to allow for rice growth. After 4 months of submergence, the pH of the sample treated with 4 t ground basalt ha⁻¹ had increased from 3·61 to 3·94, with concomitant decrease of Al. In the same cycle, the soil pH increase was much higher (reaching 5·22). Ground basalt is thus comparable with GML as an acid soil ameliorant. Within the experimental period, the ground basalt had mostly disintegrated and dissolved. The solution pH had further increased (to 5·94) in the second cycle because of dissolution of more ground basalt. This means that it takes time for ground basalt to completely dissolve and consequently supply Ca, Mg, K and P to the growing crop in the field. Applying 0·25 t organic fertilizer ha⁻¹ into the soil had no significant effect on either pH or Al. This form of organic matter (compost) contains essential nutrients. It is recommended that 4 t ground basalt should be applied in combination with 0·25 t organic fertilizer ha⁻¹ a few months ahead of the growing season for maximal benefit. This study showed that ground basalt can be effectively used to ameliorate highly acidic soils. Copyright © 2011 John Wiley & Sons, Ltd.     

Neopestalotiopsis clavispora and Pseudopestalotiopsis camelliae-sinensis causing grey blight disease of tea (Camellia sinensis) in Malaysia

European Journal of Plant Pathology - Tea (Camellia sinensis) is a popular and extensively consumed beverage in Malaysia along with many other countries around the world. Grey blight is one of the...     

Effects of oil pollution at Kuwait's Greater Al-Burgan oil field on the timing of morning emergence, basking and foraging behaviors by the sand lizard Acanthodactylus scutellatus

An attempt was made to study the effects of oil pollution in a desert location (the Greater Al-Burgan oil fields, an area damaged in the second Gulf War) in Kuwait on the behaviour of the Sand lizard A. scutellatus. Polluted sites with apparently different degrees of contamination (namely tar mat, soot and clear sites) were compared with control areas outside this region. Between 2002 and 2003, ten lizards (5 of each sex) on each polluted and each control site were observed in the field at a time of the year when they were highly active. Air, substrate and burrow temperatures were recorded and lizards were monitored for their morning emergence times, as well as their basking and foraging activities. The present study confirmed that the morning emergence times and the basking behavior varied in sand lizards among the different pollution site categories. Physical changes in the tar mat sites caused the substrate temperatures in these locations to rise more quickly in the morning in response to solar gain than was the case in the other sites. This gives lizards in these locations the opportunity to emerge earlier and to start eating more quickly, giving them an energetic advantage (perhaps, in turn, influencing their rates of growth and fecundity). The clear sites had the next earliest emergence and were the next hottest but it is difficult to account for this in terms of the physical characteristics of this site. The basking times were clearly shorter on the dark soot and tar mat sites that appeared to have higher solar gain than control or clear sites. There did not appear to be any obvious differences in foraging activity of lizards in the different locations. It appears that some aspects of simple behaviour in these lizards provides a reliable, noninvasive indices for assessing oil pollution in desert locations. The precise impact of these changes in these reptiles on their long-term viability needs to be evaluated.     

准噶尔盆地东南缘绿洲-荒漠交错带土壤甲螨群落结构

为了查明准噶尔盆地东南缘绿洲-荒漠交错带土壤甲螨群落特征,2011年4月、7月、9月、11月中旬对该交错带的自然林、灌木林、防护林、荒草原、耕地、菜瓜地和荒漠等7种不同生境进行调查。结果表明:该区域共捕获土壤甲螨成体3767头,28科36属43种,其中覆盖头甲螨、萨勒盖头甲螨、新疆尖棱甲螨和普通尖棱甲螨为优势种,截合若甲螨、长单翼甲螨属、白上罗甲螨大洋亚种为亚优势种,优势种和亚优势种占总数的72.45%。7种不同生境土壤甲螨群落组成和数量分布均有明显的差异(P<0.05),在自然林种类(30种)和个体数(1001头)最多,而在菜瓜地种类(9种)最少,荒漠个体数(118头)最少。不同生境土壤甲螨的个体数具有明显季节变化差异(P<0.05),秋季数量最高、冬季次之、夏季其次、春季最低。MGP分析结果表明,该交错区土壤甲螨群落均属于O型,但G群的种类明显高于M群和P群。甲螨的群落异质性高,各生境间的多样性指数(H)有一定的差异,其中防护林最高,而菜瓜地最低。生境间相似性分析表明,自然林、灌木林、防护林生境之间是中等相似(0.50～0.70),荒漠和荒草原与其他生境间为中等不相似(0.25～0.50)或极不相似(0.00～0.25)。研究表明气候、植被和土壤差异是影响土壤甲螨群落的主要因素。