57 research outputs found
Émissions d'oxydes d'azote par la macrofaune de sol tropical : impact des régimes alimentaires des ingénieurs de sol et des communautés microbiennes fonctionnelles impliquées dans ces émissions
No full textLes sols représentent environ 63% des émissions de N2O et à eux seuls les sols tropicaux représentent 23% de ce budget soit une contribution bien plus élevé que les sols tempérés. Ces sols sont connus pour abriter une grande biodiversité d'invertébrés dominés par quatre types i.e. termites, vers de terre, fourmis et larves de scarabaeid. Ces groupes macrofaunal sont considérés comme des ingénieurs des sols via notamment leurs actions de régulation de la disponibilité des ressources chimiques, tels que l'azote minéral pour les micro-organismes. Cette régulation est due à leurs capacités de digestion spécifiques de la matière organique ainsi que la création et/ou la modification des habitats des sols. Cette étude est basée sur l'hypothèse suivante (i) l'environnement digestif et les structures biogéniques de ces ingénieurs du sol sont considérées comme des « hot spot » d' émissions de N2O (ii) les taux d'émission de N2O varient en fonction de leurs régimes alimentaires, cette macrofaune ingérant des substrats avec différents C:N (iii) le taux d'émission de N2O de chaque invertébré est corrélé à la densité des communautés bactériennes digestives impliquées dans l'émission de N2O (bactéries nitrifiantes et dénitrifiantes) et à leur teneur en azote minéral dans leur tube digestif. Pour évaluer ces différentes hypothèses, des mesures des taux d'émission de N2O ont été effectuées in vitro en aérobiose pour la macrofaune (30 espèces différentes en provenance d'Afrique, d'Amérique du Sud et d'Europe) et leurs matériels biogéniques associées (nids, turricules). L'abondance des gènes fonctionnelles des bactéries nitrifiantes (AOA et AOB) et dénitrifiantes (nirK, nirS, nosZ) ont été quantifiés par PCR quantitative. Les termites humivores et champignonnistes ainsi que les larves de scarabaeid émettent des quantités significatives de N2O alors que les fourmis n'en émettent pas. Quand aux termites xylophages et litièrivore, ils absorbent le N2O. Les structures biogéniques des vers de terre (turricules) et des fourmis (nid) émettent des quantités importantes de N2O ce qui n'est pas le cas des nids de termites. La faune du sol et leurs structures biogéniques associées, sont donc, dans la majorité des cas étudiés, un lieu d'émission de N2O, confirmant ainsi notre première hypothèse. Ce travail a également démontré qu'il y a avait une étroite corrélation entre régime alimentaire et intensité de l'émission de N2O au sein de chaque type de macrofaune étudié. En revanche, l'abondance des gènes des communautés digestive nitrifiantes et dénitrifiantes et le contenu en N minéral au sein du tube digestif ne semblent pas être des proxies pertinents des émissions de N2O. A partir de ces mesures, des calculs ont été effectuées pour déterminer l'importance de ces émissions à l'échelle des écosystèmes tropicaux étudiés (forêt et savane). Ces calculs suggèrent que la macrofaune du sol dans ces écosystèmes pourrait contribuer entre 0,1 à 11,7% et 0,1 à 8,8% du budget total des émissions de N2O, respectivement. Les résultats de ces travaux devraient contribuer à une meilleure prise en compte de la composante biotique dans la modélisation des émissions de gaz à effet de serre provenant des sols en milieu tropical.Soils account for about 63% of N2O emissions. Tropical soils are estimated to emit 23% of global N2O emission budget which is much higher than temperate soil N2O emissions. These soils also harbor a huge biodiversity of invertebrates dominated by four types of macrofauna i.e. termites, earthworms, ants and scarabaeid grubs. These macrofaunal groups are considered as soil engineers because they regulate the availability of chemical resources, like mineral nitrogen, for the microorganisms via their specific digestion capabilities and/or by creating and modifying soil habitats. This study is based on the following hypothesis (i) the gut environment or biogenic structures of these soil engineers are considered as hotspots of N2O emission (ii) the N2O emission rates will vary according to their feeding behavior as these macrofauna thrive on diverse substrates with different C:N ratio (iii) the rate of N2O emission in each soil fauna will also depend on the gut density of the bacterial communities involved in the N2O emission (nitrifiers and denitrifiers) and on the mineral nitrogen content within the gut. To assess these different hypotheses in-vitro short-term N2O emission rates were assessed for either live macrofauna (30 species collected from Africa, South America and Europe) or their biogenic materials or both under aerobic incubations. Genes abundance of nitrifiers (AOA and AOB) and denitrifiers (nirK, nirS, nosZ) were quantified by real time quantitative PCR. Soil-feeders and fungus-growing termites and scarabaeid grubs emitted in-vivo N2O while ants did not. Surprisingly, wood- and grass-feeding termites revealed an uptake of N2O. Biogenic structures of earthworms and ants emitted substantial amount of N2O while those of termites did not. The emission difference between macrofauna or their biogenic materials and their control materials was significant for most of the macrofaunal groups studied confirming our first hypothesis. We also confirmed that the feeding behavior (total N content and C:N ratio of food material) is the main factor explaining the observed N2O emission pattern of each macrofaunal group investigated whereas genes abundances, particularly of denitrifiers and gut N mineral content did not appear to be relevant proxies of the N2O emissions rates. A back-on-the-envelope data upscaling suggests that soil macrofauna could contribute from 0.1–11.7% and 0.1–8.8% of the total soil N2O emissions, respectively, for the tropical rainforest and dry savanna ecosystems. This work should contribute to a better estimation of the soil biotic compartment in the different models of greenhouse gas emissions from tropical soils
Molecular and Functional Characterization of Elicitor PeBC1 Extracted from <i>Botrytis cinerea</i> Involved in the Induction of Resistance against Green Peach Aphid (<i>Myzus persicae</i>) in Common Beans (<i>Phaseolus vulgaris</i> L.)
No full textElicitors are biofactors that induce resistance in plants against different insect pests. This in vitro study evaluated the impact of a novel elicitor protein PeBC1, extracted from a necrotrophic fungus Botrytis cinerea, on the development and fecundity parameters of green peach aphid (Myzus persicae) on common beans (Phaseolus vulgaris L.). Three different concentrations of PeBC1 elicitor (i.e., 33.56, 25.43, 19.33 µg mL−1) were applied at three different temperature regimes (i.e., 18, 21, and 25 °C). Elicitor treatments were applied topically on the bean plants at 3-leaf stage and newly emerged (0⁻6 h old) apterous adult aphids were exposed to these treated leaves. In addition to the biological parameters of aphids, the relative expression levels of key genes associated with jasmonic acid (JA) and salicylic acid (SA) plant defense pathways were also determined through RT-qPCR. Results of bioassays revealed that the application of PeBC1 elicitor protein exhibited pronounced and significant (p < 0.05) sub-lethal effects on green peach aphids. The fecundity was reduced and the nymphal development time was prolonged by different concentrations of PeBC1 elicitor and temperature regimes. Gene expression studies showed that the exogenous application of PeBC1 induced a significant upregulation of the expression levels of JA and SA pathway-associated genes in bean plants. As compared to control, elicitor-treated plants exhibited an induced resistance against aphids. Our findings suggest the potential use of PeBC1 elicitor protein in future bio-intensive management strategies against sap-sucking insect pests such as green peach aphids
In Vitro Pathogenicity of Some Entomopathogenic Fungal Strains against Green Peach Aphid Myzus persicae (Homoptera: Aphididae)
No full textGreen peach aphid, Myzus persicae (Hemiptera: Aphididae), is an economically important pest of crops within more than 40 plant families all over the world. This study encompasses in-vitro pathogenicity of two strains of Beauveria bassiana (BB-72 and BB-252) and one strain of Lecanicillium lecanii (V-4) against green peach aphid (M. persicae). Using a leaf-dip method, three different bioassays were conducted comprised of filtrates and conidial concentrations of BB-72, BB-252 and V-4 fungal strains and their binary combinations. Infiltrate bioassays, 2 mL fungal filtrate of each strain was used. In conidial bioassays, three different concentrations (i.e., 1 × 106, 1 × 107 and 1 × 108 conidia mL−1) of each fungal strain were used, while in binary combination bioassays, LC50 and LC33 of these fungal strains were evaluated. According to the results, maximum pathogenicity against test aphids was observed at 10th day of all treatments. Both strains of B. bassiana (BB-72 and BB-252) exhibited higher mortality of aphids (up to 95 and 91%, respectively) than L. lecanii (V-4) strain (87%) in all three types of bioassays. Moreover, binary combinations of BB-72 and BB-252 strains showed significantly higher aphid mortality (94%) than other combinations. Reduced mortality in case of fungal combinations of V-4 strain might be due to the antagonistic effect of L. lecanii strain along with both strains of B. bassiana. Nevertheless, evaluation of combined pathogenicity of the fungal strains constitutes the novelty of this in-vitro study which revealed that both strains of B. bassiana (i.e., BB-72 and BB-252) are mutually compatible and can be utilized together as new biocontrol tools against destructive insect pests such as M. persicae
Folio
No full textPlatinum EditionGod Bless Them! pp. 1; In Memory of Prof. Khurshid A. Gill. pp. 2; Sandhu, M. Y.-Poetry-Memories of the Bye-gones. pp. 2; Arif Qureshi-In dulcet memory... pp. 3-4; Arif Qureshi-Poetry-Reminiscences. pp. 4; Ravia Shabeen-The Folio (Registering its History). pp. 5-6; Folio (Year by Year). pp. 7-8; Interview-The Living Legend (F.E. Chaudhry is the oldest Formanite alive, to the best of our knowledge). pp. 9-10; Interview-An Hour with Mian Muhammad Somroo. pp. 11-12; Zainab Mohsin-Buildings. pp. 13-14; Agha Mohsin Sohail-Formanites Are Great. pp. 15-17; Once A Formanite... Always A Formanite. pp. 18-20; Haque Nawaz Cheema-Love for my Institution. pp. 21; Agha Saeed-Old is Gold, New is Silver. pp. 22; Lamia Islam Khan-My Favourite Place. pp. 23; Sara Kanwal-Motivation Forever. pp. 24-25; Bilkis Hussain-Before Sunset. pp. 26; Farid A. Malik-Back to 1958. pp. 27-28; The Excellers. pp. 29-30; Position Holders (Convocation 2008). pp. 31; Survey. pp. 33-34; Donald Alfred Smith-Poetry-A Valentine. pp. 35; Easha Farooq-Love - A Human Need. pp. 36; Fatima Majeed-Defining Love. pp. 37; Bahawal Shehryar-A Fundamentalist. pp. 38; Farhat Aziz-Essay-Concept of Love in Christianity and Islam. pp. 39-40; Fatima Tahir-Mother's Love. pp. 41; Rabiya Khawar-A Blessing for the Two Worlds. pp. 42; Anam Khalid-Etymology of Love. pp. 43; Noor Nisha-Beauty of Love. pp. 44; Ayesha Rana-The Ultimate Aim. pp. 45; Madiha Sundas Rana-I Love thee for a Heart that is Kind. pp. 46; Rabiya Khawar-True Love Never Dies. pp. 47; Amina Jamil-Love - A Timeless Essence. pp. 48; Farhan Hashmi-Love Its Immortal. pp. 49; Kashifa Khalid-A Quest. pp. 50; Daud Aziz Khokher-Love!!! pp. 51-52; Bilkis Hussain-The Truth about Love!!! pp. 53; Alvi, M. Zohaib-Love in Politics. pp. 54; Fatima Arif-Waiting to be Loved like Before. pp. 55-56; Azzam Saddique-Essay-My Symphony for the Deaf. pp. 57-59; Rabiya Khawar-The Quaid-e-Azam. pp. 60-61; Tajwar Ali-Essay-The Unique Location of My Gilgit Baltistan. pp. 62-63; Ramla Ashfaq-Turn Minus Into Plus. pp. 64; Furqan Ali Akhtar-My Childhood Love. pp. 65-66; Kashifa Khalid-Silent Screams. pp. 67-68; Beenish Khokhar-Where we Started? Where we end? pp. 69-70; Omer Habib-Falling Apart. pp. 71; Sobia Kiran-A Speech by my Dream-Minister. pp. 72-74; Interview-An Evening with Javed Iqbal. pp. 75-79; Adil Khurram-Story-Deception. pp. 81-82; Shehzad, M. Shehril-Story-Whatever happened to... pp. 83; Bhatti, M. Umar-Story-Spell. pp. 84-85; Usman Khalid-Story-Love. pp. 86; Umer Murtaza Qureshi-Story-Road Kill. pp. 87-88; Shehzad, M. Shehril-Story-...as I sat down, I sensed something was Different... pp. 89; Hassan Noor Assad-Story-Born Again. pp. 90; Muhammad Adeel-Story-The Cookies. pp. 91-92; Waseem Anwar-Poetry-Out West and the Rule of the Law. pp. 93; Zainab Mohsin-Poetry-Life goes on. pp. 94; Bilkis Hussain-Poetry-Paint me, please. pp. 94; Minam Ahmed-Poetry-Mother. pp. 95; Usman Nasir-Poetry-My tears. pp. 95; Jahanzaib Aslam-Poetry-Untitled. pp. 96; Mehwish Shafi-Poetry-A Fairy Who Lives with Me. pp. 96; Rashion Sajid-Poetry-Old days. pp. 97; Abdul Rehman-Poetry-Essence. pp. 97; Saadia Riaz Sehole-Poetry-Can you justify it? pp. 98; Saad Sarfraz Sheikh-Poetry-The Wishlist thing of mine. pp. 98; Razzaq, M. Sarmad-Poetry-Till we meet again. pp. 99; Fariha Qayyum-Poetry-We...The Formanite. pp. 99; Sohaib Zaheer-Poetry-By Love Serve One Another. pp. 100; Fakiha Komal-Poetry-The Lost Love. pp. 100; Irteza Rehman-Poetry-Realization. pp. 101; Sana Jennifer-Poetry-The Art of Giving. pp. 102; Rizwan Kamran-Poetry-Guess! Who is it? pp. 102; Kamran Akram Gondal-Poetry-Common Things. pp. 103; Rabia Ashfaq-Poetry-The Dying Sun. pp. 103; Hafiz Muhammad Hamza Sehole-Poetry-My Dear Parents. pp. 104; Farhan Hashmi-Poetry-Innocence. pp. 104; Ahmed Farooq-Poetry-All I see is You. pp. 105; Sadia Riaz Sehole-Poetry-Life is at Risk. pp. 105; Goraya, M. Furqan-Poetry-Friendship. pp. 106; Omar Farooq-Poetry-Birth. pp. 106; Iqbal, M. Shaheer-Poetry-In the Shades of Blossom. pp. 107; Nauman Ahmed-Poetry-Life is not what I thought it to be. pp. 107; Haider, S. Zulqarnain-Poetry-Truth. pp. 108; Goraya, M. Furqan-Poetry-Examinations. pp. 108; Prof. Arif Qureshi-Poetry-Dreams. pp. 109; Sheraz Ashraf-Poetry-Lonely Heart. pp. 109; Easha Farooq-Poetry-Winter's Tale. pp. 110; Sana Alvi-Poetry-After She Left Me. pp. 110; Sandhu, M. Y.-Poetry-She comes Not. pp. 111; Erum George-Poetry-Change. pp. 111; Muhammad Adeel-Poetry-Peace. pp. 112; Adeel Anwar-Poetry-Vengeance. pp. 112; Azzam Saddique-A ""Prefect"" Story. pp. 113-114; Muhammad Adeel-Flirtation. pp. 115; Saad Sarfraz-Misery Loves Company. pp. 116-117; Haider F. Halim-No Donkeys in New York. pp. 118-119; Lamia Islam Khan-How to prepare a Bride? pp. 120; Saba Zareen-Modern Love Letter. pp. 121; Lamia Islam Khan-Load Shedding. pp. 122; Zafar Khattak-Application to the Staff Editor. pp. 123; Augustine, Milcah-Cartoons. pp. 124-126; Riaz Akbar Somairi-Article-Prospects of Peace in Multicultural South Asia. pp. 127-128; Bakhtawar Khan-Caste System. pp. 129-130; Abdur Rehman Farrukh-Women are not born. They are made. pp. 131-132; Fraaz Mehmud-Romanticism as a Pillar of Nationalism. pp. 133-134; Fizza Ali Shah-Is mobile phone use among youngsters really a menace? pp. 135-136; Mehreen Ali Kasana-One Muffled Scream. pp. 137-138; Kamal ud Din-Dr. Kamal ud Din. pp. 139-140; Miss Zara Hussain. pp. 141; Miss Saima Saleem. pp. 142; Beenish Khokhar-Unforgettable Tour. pp. 143-144; Rizwan Kamran-The Teacher. pp. 145; Maryam Azhar-IT: A New, Challenging Dimension. pp. 146-148; Folio [Urdu] 148 p.Editorial Board (English). 2 pages before Editorial; Advisory Board. 1 page before Editorial; Prof. Khurshid A. Gill & Mr Perviaz Rehmatullah. page 1; F. E. Chaudhry. after page 10; Mian Muhammad Somroo. before page 11; Society Presidents. before page 29; Political Cartoons created by Javed Iqbal (Famous Cartoonist). on 2 pages, after page 79; 20 pages of pictures, Memories, Commencement 2008: Convocation, Valedictory 2009, Sports Day, Line Work, The Story of Yester Years, People Who Make Difference, Campus Life, Societies, Drama. after page 148; Folio Team with Prof Dr K. K. Aziz. after page 8 (Urdu side); Editorial Board (Urdu). 1 page before Urdu Content
Effects on heat transfer of multiphase magnetic fluid due to circular magnetic field over a stretching surface with heat source/sink and thermal radiation
No full textThe purpose of the current article is to explore the boundary layer heat transport flow of multiphase magnetic fluid with solid impurities suspended homogeneously past a stretching sheet under the impact of circular magnetic field. Thermal radiation effects are also taken in account. The equations describing the flow of dust particles in fluid along with point dipole are modelled by employing conservation laws of mass, momentum and energy, which are then converted into non-linear coupled differential equations by mean of similarity approach. The transformed ODE’s are tackled numerically with the help of efficient Runga-Kutta method. The influence of ferromagnetic interaction parameter, viscous dissipation, fluid-particle interaction parameter, Eckert number, Prandtl number, thermal radiation parameter and number of dust particles, heat production or absorption parameter with the two thermal process namely, prescribed heat flux (PHF) or prescribed surface temperature (PST) are observed on temperature and velocity profiles. The value of skin-friction coefficient and Nusselt number are calculated for numerous physical parameters. Present results are correlated with available for a limited case and an excellent agreement is found. Keywords: Ferromagnetic interaction parameter, Dusty magnetic fluid, stretching sheet, Magnetic dipole, Heat source/sink, Thermal radiatio
Temporal stability analysis and thermal performance of non-Newtonian nanofluid over a shrinking wedge
No full textThe authors use a temporal stability analysis to examine the hydrodynamics performance of flow response quantities to investigate the impacts of pertained parameters on Casson nanofluid over a porous shrinking wedge. Thermal analysis is performed in the current flow with thermal radiation and the viscous dissipation effect. Boungiorno's model is used to develop flow equations for Casson nanofluid over a shrinking wedge. An efficient similarity variable is used to change flow equations (PDEs) into dimensionless ordinary differential equations (ODEs) and numerical results are evaluated using MATLAB built-in routine bvp4c. The consequence of this analysis reveals that the impact of active parameters on momentum, thermal and concentration boundary layer distributions are calculated. The dual nature of flow response output i.e. Cfx is computed for various values of βT=2.5,3.5,4.5, and the critical value is found to be −1.544996, −1.591, and −1.66396. It is perceived that the first (upper branch) solution rises for the temperature profile when the value of thermal radiation is increased and it has the opposite impact on the concentration profile. Thermal radiation has the same critical value for Nux and Shx. The perturbation scheme is applied to the boundary layer problem to obtain the eigenvalues problem. The unsteady solution f(η,τ) converges to steady solution fo(η) for τ→∞ when γ≥0. However, an unsteady solution f(η,τ) diverges to a steady solution fo(η) for τ→∞ when γ<0. It is found that the boundary layer thickness for the second (lower branch) solution is higher than the first (upper branch) solution. This investigation is the evidence that the first (upper branch) solution is stable and reliable
Effects on heat transfer of multiphase magnetic fluid due to circular magnetic field over a stretching surface with heat source/sink and thermal radiation
No full textBiodiversity and Species Distribution of Coccinellids (Coccinellidae: Coleoptera) in District Sargodha (Punjab), Pakistan
No full textNitrous oxide (N2O) emissions by termites : does the feeding guild matter ?
No full textIn the tropics, termites are major players in the mineralization of organic matter leading to the production of greenhouse gases including nitrous oxide (N2O). Termites have a wide trophic diversity and their N-metabolism depends on the feeding guild. This study assessed the extent to which N2O emission levels were determined by termite feeding guild and tested the hypothesis that termite species feeding on a diet rich in N emit higher levels of N2O than those feeding on a diet low in N. An in-vitro incubation approach was used to determine the levels of N2O production in 14 termite species belonging to different feeding guilds, collected from a wide range of biomes. Fungus-growing and soil-feeding termites emit N2O. The N2O production levels varied considerably, ranging from 13.14 to 117.62 ng N2O-N d(-1) (g dry wt.)(-1) for soil-feeding species, with Cubitermes spp. having the highest production levels, and from 39.61 to 65.61 ng N2O-N d(-1) (g dry wt.)(-1) for fungus-growing species. Wood-feeding termites were net N2O consumers rather than N2O producers with a consumption ranging from 16.09 to 45.22 ng N2O-N d(-1) (g dry wt.)(-1). Incubating live termites together with their mound increased the levels of N2O production by between 6 and 13 fold for soil-feeders, with the highest increase in Capritermes capricornis, and between 14 and 34 fold for fungus-growers, with the highest increase in Macrotermes muelleri. Ammoniaoxidizing (amoA-AOB and amoA-AOA) and denitrifying (nirK, nirS, nosZ) gene markers were detected in the guts of all termite species studied. No correlation was found between the abundance of these marker genes and the levels of N2O production from different feeding guilds. Overall, these results support the hypothesis that N2O production rates were higher in termites feeding on substrates with higher N content, such as soil and fungi, compared to those feeding on N-poor wood
- …
