Situating the diversity of Southern African environmental education scholarship within a global conversation at a critical juncture on Earth
- Authors: Olvitt, Lausanne L
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/389869 , vital:68491 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/247386"
- Description: ¬The collection of papers in Volume 38 in many ways mirrors the diversity of research methodologies and teaching approaches in the contemporary eld of Environmental and Sustainability Education. ¬ e seven papers remind us that, whilst environmental educators and researchers are largely in agreement over the nature and causes of the social-ecological problems that we face in sub-Saharan Africa, there is less certainty around what types of educational approaches and pedagogies are adequate to help resolve them. ¬ e papers in this volume either o er pedagogical innovations that may strengthen teaching and learning for sustainable futures, or they provide insights into the social, cultural and economic contexts in which such teaching and learning occurs.
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Symmetry effect of cobalt phthalocyanines on the aluminium corrosion inhibition in hydrochloric acid
- Authors: Nnaji, Nnaemeka , Sen, Pinar , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/231323 , vital:49877 , xlink:href="https://doi.org/10.1016/j.matlet.2021.130892"
- Description: The aluminium corrosion retardation potentials of phthalocyanine-based dyes, cobalt (II) 2,9,16-tris(4-(tert-butyl)phenoxy)-23-(pyridin-4-yloxy)phthalocyanine (D1) and cobalt (II) 2,9,16,24-tetrakis(4-(tert-butyl)phenoxy)phthalocyanine (D2) in 1 M hydrochloric acid were evaluated. Results from potentiodynamic polarization measurements show that inhibition efficiency increased with inhibitor concentration at 28 °C with values of 91.9 % and 87.0 % values respectively for D1 and D2 at 10 μM.
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Traumatic Imagination in Traditional Stories of Gender-Based Violence
- Authors: Ahmad, Ayesha , Ahmad, Lida , Andrabi, Shazana , Ben Salem, Lobna , Hughes, Peter , Mannell, Jenevieve , Paphitis, Sharli A , Senyurek, Gamze
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426548 , vital:72362 , xlink:href="https://journalofethics.ama-assn.org/article/traumatic-imagination-traditional-stories-gender-based-violence/2022-06"
- Description: Traumatic imagination includes creative processes in which traumatic memories are transformed into narratives of suffering. This article emphasizes the importance of storytelling in victims’ mental health and offers a literary perspective on how some women’s experiences of suffering can be expressed in the telling of traditional stories, which confer some protection from stigma to individual women in Turkish and Afghan societies.
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A heavy-atom-free π-extended N-confused porphyrin as a photosensitizer for photodynamic therapy
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185909 , vital:44447 , xlink:href="https://doi.org/10.1039/d1nj00112d"
- Description: The synthesis and characterization of a novel 1,3-diethyl-2-thiobarbituric-acid-substituted N-confused porphyrin (NCP-TB) is reported, along with a study of its photodynamic activity against MCF-7 cells using 530 (110 mW cm−2) and 660 nm (280 mW cm−2) Thorlabs light-emitting diodes for 30 min. The singlet oxygen quantum yield for NCP-TB is 0.38 compared to 0.23 for the parent unsubstituted N-confused porphyrin (NCP) due to the presence of a sulfur atom. NCP-TB exhibits enhanced PDT activity compared to NCP at both wavelengths. A significantly lower IC50 value of 5.2 μM was obtained at 530 nm (14.7 μM at 660 nm) despite a smaller light dose, due to a large red shift of the intense B band into the green region of the spectrum. 2′,7′-Dichlorofluorescein diacetate (DCFDA) assays demonstrate that there is intracellular generation of reactive oxygen species upon exposure to light.
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Naked Eye and Colorimetric Detection of Cyanide with a 1, 3‐Diethyl‐2‐thiobarbituric Acid Substituted Ferrocene Chemosensor
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190567 , vital:45006 , xlink:href="https://doi.org/10.1002/slct.202100163"
- Description: A 1,3-diethyl-2-thiobarbituric-acid-substituted ferrocene (FET) has been evaluated for its cyanide sensing ability by UV-visible absorption spectroscopy and other characterization methods. FET provides a ratiometric colorimetric chemosensor for the CN− anion detection in 1 : 1 DMSO/H2O (v/v) solution. The addition of CN− results in an immediate color change from dark blue to pale orange that is visible to the naked eye. Mechanism studies and molecular modelling with TD-DFT calculations demonstrate that nucleophilic addition of CN− to an electrophilic sp2-hybridized carbon atom blocks charge transfer from the ferrocene ring complex to the thiobarbituric acid moiety. The FET sensor exhibits excellent selectivity for CN− and a limit of detection of 0.2 μM.
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Fucoidan from Ecklonia maxima is a powerful inhibitor of the diabetes-related enzyme, Éø-glucosidase
- Authors: Daub, Chantal D , Mabate, Blessing , Malgas, Samkelo , Pletschke, Brett I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425982 , vital:72304 , xlink:href="https://doi.org/10.1016/j.ijbiomac.2020.02.161"
- Description: Ecklonia maxima, an endemic South African seaweed, is a potential source of beneficial bioactive compounds. Among these compounds, fucoidan, a sulphated polysaccharide has a wide range of bioactivities including anti-diabetic activity. In this study, fucoidan was extracted from E. maxima by the hot water extraction method and then characterised by colorimetric assays for sugar composition. The extraction from E. maxima yielded 6.89% fucoidan which was found to contain 4.45 ± 0.25% L-fucose and 6.01 ± 0.53% sulphate. The water extracted E. maxima fucoidan had a low molecular weight of approximately 10 kDa. Structural studies (FT-IR, NMR and XRD) confirmed the structure and integrity of the fucoidan to be similar to previously studied fucoidans in literature. Finally, the activities of starch digestive enzymes; α-amylase and α-glucosidase, were investigated in the presence of the E. maxima fucoidan extract. Fucoidan from E. maxima was observed to be a potent mixed-type inhibitor of α-glucosidase with an IC50 range of 0.27–0.31 mg.ml-1, which was significantly lower than the commercial anti-diabetic standard, acarbose. Our present study demonstrated that fucoidan from E. maxima is a more powerful inhibitor compared to some standard anti-diabetic compounds and thus shows great potential for managing type 2 diabetes.
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Bushmeat use is widespread but under-researched in rural communities of South Africa
- Authors: Martins, Vusumzi , Shackleton, Charlie M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179745 , vital:43167 , xlink:href="https://doi.org/10.1016/j.gecco.2019.e00583"
- Description: Bushmeat hunting and consumption is common throughout sub-Saharan Africa. Yet, a recent review indicated that the prevalence and nature of bushmeat hunting was little researched or understood in southern African savannas. Here we present information from a number of rural livelihoods studies in South Africa that indicate that bushmeat consumption is common, with typically between 30 and 60% of rural households in the communal tenure regions stating that they consume it. Yet there are only five studies in the country explicitly investigating bushmeat hunting practices, motivations, offtake and target species. A review of the five studies indicates that bushmeat hunting is largely a male activity and that motivations and practices vary between sites. Hunting with dogs is the most common method, targeting multiple small and medium-sized species. With such widespread consumption, it is possible that bushmeat hunting may have significant effects on the population status of some target species and consequently requires urgent and in-depth research of both practices and effects
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Chlorophyll fluorometry as a method of determining the effectiveness of a biological control agent in post-release evaluations
- Authors: Miller, Benjamin E , Coetzee, Julie A , Hill, Martin P
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417438 , vital:71453 , xlink:href="https://doi.org/10.1080/09583157.2019.1656165"
- Description: The impact of the planthopper Megamelus scutellaris, a biocontrol agent of water hyacinth in South Africa, was assessed using chlorophyll fluorometry in a greenhouse study under two different eutrophic nutrient treatments and agent densities (high and low). The results indicated that plants grown in low nutrients with high densities of M. scutellaris showed the greatest reduction in the fluorescence parameters Fv/Fm and PIabs. The successful use of chlorophyll fluorometry for the detection of subtle insect damage to water hyacinth leaves could have future application in post-release studies to measure the impact of M. scutellaris in the field.
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Pereskiophaga brasiliensis, a natural enemy of the invasive alien cactus Pereskia aculeata, is not suitably host specific for biological control in South Africa
- Authors: Paterson, Iain D , Muskett, Phillippa C , Mdodana, LL , Vitorino, M D
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417498 , vital:71458 , xlink:href="https://doi.org/10.1080/09583157.2019.1581132"
- Description: The stem-mining weevil, Pereskiophaga brasiliensis, was a candidate biological control agent for the invasive cactus Pereskia aculeata in South Africa. In host specificity trials, it developed on two indigenous test plant species under choice and no-choice conditions. Pereskiophaga brasiliensis is therefore not suitably host specific for release in South Africa.
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Phytochemical, anti-inflammatory and anti-trypanosomal properties of Anthocleista vogelii Planch (Loganiaceae) stem bark
- Authors: Eze, Fabian I , Siwe-Noundou, Xavier , Osadebe, Patience , Krause, Rui W M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/194059 , vital:45419 , xlink:href="https://doi.org/10.1016/j.jep.2019.111851"
- Description: Ethnopharmacological relevance: Anthocleista vogelii Planch (Loganiaceae) is used in African Traditional Medicine for the treatment of pain and inflammatory disorders as well as sleeping sickness. Aim of the study: To determine the in vivo anti-inflammatory and in vitro anti-trypanosomal activities of the extracts of A. vogelii stem bark and identify the phytochemical classes of the fractions responsible for the activities. Materials and methods: The in vivo anti-inflammatory activity of the extracts was evaluated using the egg albumin-induced rat paw oedema model while the in vitro anti-trypanosomal activity was assessed on Trypanosoma brucei brucei. The in vitro cytotoxicity was assessed on HeLa (human cervix adenocarcinoma) cell line. Results: The methanolic extract of A. vogelii stem bark, with 11.2% yield, gave LD50 > 5000 mg/kg. The n-hexane fraction of the extract contains steroids, terpenes and fatty acids and yielded non-cytotoxic terpenoidal column fraction with anti-trypanosomal IC50 of 3.0 μg/mL. The ethylacetate fraction at 100 mg/kg dose significantly (p less than 0.05) provoked 37.8, 62.5 and 69.7% inhibition of oedema induced by egg-albumin at the second, fourth and sixth hours respectively. Conclusion: The study demonstrated that the anti-inflammatory and anti-trypanosomal activities of A. vogelii are probably due to non-cytotoxic terpenoids and validated the traditional use of A. vogelii in the treatment of inflammation and sleeping sickness.
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The Stinking Ontology of Sh#t in the Water: Higher Education Public Pedagogy and “Existance”?
- Authors: Lotz-Sisitka, Heila
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182754 , vital:43871 , xlink:href="http://doi.org/10.1089/sus.2019.29161"
- Description: “Existance” is not a spelling mistake. It is a word from Soweto street poet Zachariah Rapola’s poem, questioning our “stance in existence” . In the context of this essay, the poem raises the challenging perspective of our “stance in existence.” for engaging with the SDGs. The SDGs set a range of clear targets, but in doing so, they fail to give a good account of the stinking ontology of some of the issues to be dealt with, and thus lack a certain sense of realism.
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Porphyrin dimers with a bridging chiral amide-bonded benzo-moiety
- Authors: Liang, Xu , Qin, Mingfeng , Zhou, Lin , Liu, Tingting , Li, Minzhi , Mack, John , Ndebele, Nobuhle , Nyokong, Tebello , Zhu, Weihua
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233433 , vital:50090 , xlink:href="https://doi.org/10.1016/j.dyepig.2018.02.043"
- Description: The facile synthesis and characterization of four porphyrin dimers which introduced stereomeric centers with chiral amide-bonded para- and meta-disubstituted benzo-moiety is reported. Trends in the electronic structures and optical and redox properties are analyzed through a comparison with theoretical calculations to explore the effect of positional isomerism of the bridging benzene rings.
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Photolytic changes in the morphology of porphyrin-phthalocyanine nanostructures (P-PcNs) in the presence of platinum and gold salts
- Authors: George, Reama C , D'Souza, Sarah , Durmus, Mahmut , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190416 , vital:44992 , xlink:href="https://doi.org/10.1080/24701556.2017.1284085"
- Description: Porphyrin-phthalocyanine nanostructures (P-PcNs) have been fabricated by electrostatic self-assembly of two oppositely charged molecules. The negatively charged molecule, meso-tetra-(4-phenylsulphonate)porphyrin (HT) and the positively charged species; {1,(4)-tetrakis-[(N-methyl(3-pyridyloxy) phthlocyaninato] chloro gallium(III)} sulphate, {2,(3)-tetrakis-[(N-methyl{(2-mercaptopyridine) phthalocyaninato} hydroxy manganese(III)} sulphate, {1,(4)-tetrakis-[(N-methyl-(3-pyridyloxy) phthalocyaninato] chloro indium(III)} sulphate, {2,3-octakis-{[(N-methyl-2-mercaptopyridine) phthalocyaninato] acetato manganese(III)} sulphate, {2,(3)-tetrakis-[(N-methyl(3-pyridyloxy) phthlocyaninato] choro gallium(III)} sulphate, {2,3-octakis-[(N-methy-3-pyridyloxy) phthalocyaninato] chloro indium(III)} sulphate, and {2,(3)-tetrakis-[(N-methyl (3-pyridyloxy) phthalocyaninato] chloro indium(III)} sulphate. Transmission electron microscopic (TEM) images showed that the formed nanostructures ranged from nanosheets to nanorods and nanotubes. The UV-Vis spectra confirmed that the molecules formed J-aggregates. The P-PcNs were exposed to incandescence light in the presence of platinum and gold salts. It was observed that the presence of platinum salts resulted in the destruction of the P-PcNs with possible formation of a Pt-Pc complex. While with the gold salt, the structures of P-PcNs were not only retained but were also enhanced to longer nanorods and nanofibers with the formation of gold nanoparticles.
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Reader in comedy
- Authors: Krueger, Anton
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/225684 , vital:49248 , xlink:href="https://doi.org/10.1080/10137548.2017.1409523"
- Description: I really enjoyed this selection of excerpts on comedy. In 64 extracts, this comprehensive anthology covers 2375 years of mainly philosophical texts in 375 dense pages. From 360 BCE (Plato’s Philebus) to just the other day (Romanska’s Disability in Tragic and Comic Frame [2015]), this is an immense resource covering a lot of ground. The extracts don’t all apply specifically to theatre, though this is where the discussion begins, with the ancients. Later on, as new genres emerge, there are also entries relating to prose, film, story-telling and stand-up; but mainly, the writings have to do with laughter itself, and the role and function of comedy.
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The optical limiting of blue and green ytterbium double-decker phthalocyanines in solution and in poly (acrylic acid) as thin films
- Authors: Sekhosana, Kutloana E , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188585 , vital:44767 , xlink:href="https://doi.org/10.1016/j.ica.2016.05.026"
- Description: Bis{1(4), 8(11), 15(18), 22(25)-tetra(4-tert-butylphenoxy)phthalocyaninato} ytterbium(III) (2a) (the green form) was synthesized and reduced to form 2b (the blue form). Nonlinear optical parameters for complex 2 in green and blue forms were determined using the Z-scan technique and the values of third-order imaginary susceptibility (Im[χ(3)]) and second-order hyperpolarizability (γ) of the order of 10−9 (for 2b) and 10−27 esu, respectively, were obtained in solution. In poly(acrylic acid) as a thin film, complex 2a showed extremely high Im[χ(3)] and γ values of the order 10−8 and 10−25 respectively. A low optical limiting threshold value of 0.075 J cm−2 was obtained for the thin film 2a.
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HPLC method for simultaneous analysis of ranitidine and metronidazole in dosage forms
- Authors: King'ori, Loti D , Walker, Roderick B
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184790 , vital:44272 , xlink:href="https://doi.org/10.14233/ajchem.2014.15432"
- Description: A simple, rapid, precise and accurate stability indicating HPLC method for the simultaneous analysis of metronidazole and ranitidine in dosage forms has been developed and validated. Calibration curves for metronidazole and ranitidine exhibited linearity (R2 = 0.9995 for both compounds) over the concentration ranges investigated. The method was sensitive, selective and accurate for both compounds. Both drugs were found to be stable following acid hydrolysis studies. However, following alkali hydrolysis degradation of both compounds was observed. Furthermore metronidazole appeared to be stable following oxidative studies however ranitidine underwent complete degradation under these conditions. Both drugs were well resolved from the degradation products. The stability indicating chromatographic method has the necessary precision and accuracy for the simultaneous analysis of metronidazole and ranitidine in dosage forms.
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Synthesis and physicochemical behaviour of aluminium bis and tris (diammine platinum) octacarboxyphthalocyanine
- Authors: Malinga, Nduduzo , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241970 , vital:50988 , xlink:href="https://doi.org/10.1016/j.poly.2013.02.073"
- Description: Hydroxy aluminium octacarboxy phthalocyanine (Al(OH)OCPc) was conjugated with a diammine platinum complex to give conjugates containing two or three platinum complexes (represented as: Al(OH)OCPc(Pt)2 and Al(OH)OCPc(Pt)3). It was found that the complexes were soluble in water at a pH > 8.2. Both conjugates were found to have two fluorescence lifetimes. The triplet and singlet oxygen quantum yields increased for the conjugates compared to Al(OH)OCPc alone.
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The Dangers of Student-Centered Learning-A Caution about Blind Spots in the Scholarship of Teaching and Learning
- Authors: McKenna, Sioux
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187362 , vital:44624 , xlink:href="https://doi.org/10.20429/ijsotl.2013.070206"
- Description: Student-centered learning is an increasingly popular approach that shifts the focus from the teacher to the student. The approach argues that we need to have a clear understanding of who our students are and what their needs are in order for us to provide quality education. This paper applauds the focus on the student but raises two concerns about absences in this approach. Firstly, student-centered approaches rarely consider the actual knowledge being taught and learnt. There is little consideration of how the disciplinary knowledge is constructed and what norms and values underpin such constructions. Secondly, student-centered approaches are often undertaken within the dominant autonomous discourse where student success or failure is seen to result from characteristics inherent in the student. She is understood as an individual rather than as a member of a larger social group and there is equally little acknowledgement of the socially constructed nature of universities and the practices within them.
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The synthesis and characterisation of magnetic nanoparticles and their interaction with a zinc phthalocyanine
- Authors: Antunes, Edith M , Rapulenyane, Nomasonto , Ledwaba, Mpho , Litwinski, Christian , Chidawanyika, Wadzanai J U , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/242111 , vital:51002 , xlink:href="https://doi.org/10.1016/j.inoche.2012.12.010"
- Description: A variety of nanoparticles (NPs), including FePt nanoparticles with Fe as the shell (2) or Pt as the shell (3), Pt NPs (4), and FePd (5) were synthesised, characterised and their effect on a zinc phthalocyanine (1) tetra-substituted with a pyridyl-oxy substituent studied using UV/Vis and fluorescence spectroscopy (including time correlated single photon counting, TCSPC). The nanoparticles were characterised using a number of techniques including UV/Vis and inductively coupled plasma-optical emission (ICP-OES) spectroscopies, transmission electron microscopy (TEM), differential scanning calorimetry (DSC), X-ray powder diffraction (XRD) and electron paramagnetic resonance (EPR) spectroscopy. Nanocomposites (NCs, 6,7) where the ZnPc (1) was used as the stabiliser, instead of oleic acid and or oleylamine, were also synthesised and characterised.
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Weevil borne microbes contribute as much to the reduction of photosynthesis in water hyacinth as does herbivory
- Authors: Venter, Nic , Hill, Martin P , Hutchinson, Sarah-Leigh , Ripley, Brad S
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423573 , vital:72073 , xlink:href="https://doi.org/10.1016/j.biocontrol.2012.10.011"
- Description: Arthropods released for weed biocontrol can have effects other than simply removing biomass and frequently decrease photosynthetic rate more than can be attributed to the mere loss of photosynthetic surface area. Some of this effect may result because biological control agents facilitate the transfer and ingress of deleterious microbes into plant tissues on which they feed. We evaluated this facilitation effect using water hyacinth (Eichhornia crassipes) and a weevil (Neochetina eichhorniae) and compared the reductions in photosynthetic rates between leaves subject to herbivory by adult weevils sterilized with 3.5% chlorine bleach, to those that were unsterilized. The results showed that weevils carried both fungi and bacteria, transferred these to leaves on which they fed, and that microbes and biomass removal contributed almost equally to the 37% decrease in photosynthetic productivity. Hence, maximising the effectiveness of using arthropods that damage leaf surfaces for biocontrol requires the presence of microorganisms that are deleterious to plants.
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