Investigation of tutin, a naturally-occurring plant toxin, as a novel, culturally-acceptable rodenticide in New Zealand

He nui nga mātauranga a te Māori (Ngai Tūhoe) e pā ana ki nga momo hua tāokeoke (Toxins) etaea ana te whakarite hei rauemi tāwai i ngā riha kīrearea, pērā anō ki nga whiu takarangi o te tāoke 1080. I whakamātauhia e matou i nga ira tāoke o roto o te hua Tutu, ki rō taiwhanga pūtaiao. Mā te wero atu ki tētahi kiore (Norway Rat) i hua mai ngā mohiotanga o te nui me te momo o ngā tāokeoke kei roto i tēnei miro Māori, me te āhua o tēnei tāoke kia mau-rohā tonu tōna tuku whakahemo (Humaneness). Kei tua o te 55 mg kg⁻¹neke atu, te ine i tūtuki pai ai nga tāhawahawatanga o te miro Tutu, ā, e mau-roha tonu ana te kōhurutanga o te r iha. Ko te whakatau kia kawea atu tēnei kaupapa ki nga ahurewa rangahau e taea ai te waihanga i tētahi mōunu tāokeoke, kia whakamātauria ki rō ngāhere. Hei tāpiritanga ki tēnei, he roa rawa te wā e pakari ai te whanaketanga mai o tētahi tākoe e rerekē ana ki te 1080, anō nei, mā ngā kawenga o te mātauranga Māori ki tēnei take e whanake tika ai te kaupapa nei. New Zealand has many introduced mammalian species that are managed as pests of conservation and/or economic importance, including four rodent species. Vertebrate pesticides are the most important rodent management tool, largely dominated by anticoagulants such as brodifacoum, and by the metabolic disruptor, Compound 1080. There has been considerable opposition to these pesticides, primarily based on concerns about environmental persistence and non-target effects; Maori have been particularly vocal in opposition. Maori have place-based knowledge about naturally-occurring plant toxins that could be used as culturally-acceptable alternatives to existing rodenticides. In the context of the research presented here, the term ‘culturally-acceptable’ refers to new pest control options that have been co-designed with Matauranga Maori experts that inherently include Maori ways of thinking, being, and acting. Tuhoe researchers in our study wanted to pursue the most promising natural toxic compound found in native plants as a suitable alternative to current vertebrate pesticides. Therefore, we undertook an oral gavage trial to assess the toxicity of tutin, the toxin active in tutu (Coriaria arborea), to the Norway rat, (Rattus norvegicus). Tutin was toxic to this species at a dose of 55 mg kg⁻¹, with a quick, humane death compared to other existing rodenticides. At a dose rate of 55 mg kg⁻¹, all animals of both sexes died within an hour, and once neurological poisoning symptoms commenced these animals were unconscious within 5-10 minutes. We conclude it is warranted to take the next logical research step, which is to prove whether this dose rate would be technically attainable in the field. Although for now New Zealand remains reliant on 1080 and anti-coagulants for mammalian pest control, efforts should continue to develop more targeted toxins and delivery systems. We recommend incorporating Matauranga Maori to identify alternative control tools that could lead to more culturally acceptable pest control

The compensatory potential of increased immigration following intensive American mink population control is diluted by male-biased dispersal

Attempts to mitigate the impact of invasive species on native ecosystems increasingly target large land masses where control, rather than eradication, is the management objective. Depressing numbers of invasive species to a level where their impact on native biodiversity is tolerable requires overcoming the impact of compensatory immigration from non-controlled portions of the landscape. Because of the expected scale-dependency of dispersal, the overall size of invasive species management areas relative to the dispersal ability of the controlled species will determine the size of any effectively conserved core area unaffected by immigration from surrounding areas. However, when dispersal is male-biased, as in many mammalian invasive carnivores, males may be overrepresented amongst immigrants, reducing the potential growth rate of invasive species populations in re-invaded areas. Using data collected from a project that gradually imposed spatially comprehensive control on invasive American mink (Neovison vison) over a 10,000 km2 area of NE Scotland, we show that mink captures were reduced to almost zero in 3 years, whilst there was a threefold increase in the proportion of male immigrants. Dispersal was often long distance and linking adjacent river catchments, asymptoting at 38 and 31 km for males and females respectively. Breeding and dispersal were spatially heterogeneous, with 40 % of river sections accounting for most captures of juvenile (85 %), adult female (65 %) and immigrant (57 %) mink. Concentrating control effort on such areas, so as to turn them into “attractive dispersal sinks” could make a disproportionate contribution to the management of recurrent re-invasion of mainland invasive species management areas

Influence of pyridine versus piperidine ligands on the chemical, DNA binding and cytotoxic properties of light activated trans,trans,trans-[Pt(N3)2(OH)2(NH3)(L)]

The photocytotoxicity and photobiochemical properties of the new complex trans, trans, trans-[Pt(N3)2(OH)2(NH3)(piperidine)] (5) are compared with its analogue containing the less basic and less lipophilic ligand pyridine (4). The log P (n-octanol/water) values were of -1.16 and -1.84 for the piperidine and pyridine complexes, respectively, confirmed that piperidine increases the hydrophobicity of the complex. DFT and TDDFT calculations indicate that 5 has accessible singlet and triplet states which can promote ligand dissociation when populated by both UVA and visible white light. When activated by UVA or white light, both compounds showed similar cytotoxic potencies in various human cancer cell lines although their selectivity was different. The time needed to reach similar antiproliferative activity was noticeably decreased by introducing the piperidine ligand. Neither compound showed cross-resistance in three oxoplatin-resistant cell lines. Furthermore, both compounds showed similar anticlonogenic activity when activated by UVA radiation. Interactions of the light-activated complexes with DNA showed similar kinetics and levels of DNA platination and similar levels of DNA interstrand cross-linking (ca. 5 %). Also the ability to unwind double stranded DNA where comparable for the piperidine analogue (24°, respectively), while the piperidine complex showed higher potency in changing the conformation of DNA, as measured in an ethidium bromide binding assay. These results indicate that the nature of the heterocyclic nitrogen ligand can have subtle influences on both the phototoxicity and photobiochemistry of this class of photochemotherapeutic agents

Genotype MTBDR plus for direct detection of mycobacterium tuberculosis and drug resistance in strains from gold miners in South Africa

GenoType MTBDRplus is a molecular assay for detection of Mycobacterium tuberculosis and drug resistance. Assay performance as applied directly to consecutive unselected sputum samples has not been established. The objective of this study was to determine the accuracy of the MTBDRplus test for direct detection of M. tuberculosis (in sputum) and for drug resistance in consecutively submitted sputum samples. In this cross-sectional study in South Africa, one sputum specimen from each person suspected of having pulmonary tuberculosis was tested by smear microscopy, direct MTBDRplus, and Mycobacterial Growth Indicator Tube (MGIT) culture with MGIT drug susceptibility testing. MGIT results were the reference standard. We tested 2,510 sputum samples, and 529 (21.1%) were positive for M. tuberculosis by MGIT. Direct MTBDRplus identified M. tuberculosis in 256 of 529 specimens (sensitivity, 48.4%; 95% confidence interval [CI], 44.1, 52.7). The sensitivity of MTBDRplus for M. tuberculosis detection by sputum smear status was as follows: smear negative, 13.7% (95% CI, 9.8, 18.4); smear scanty, 46.2% (95% CI, 19.2, 74.9); smear 1+, 69.1% (95% CI, 55.2, 80.9); smear 2+, 86.3% (95% CI, 73.7, 94.3); smear 3+, 89.8% (95% CI, 83.7, 94.2). Direct MTBDRplus testing was negative for 1,594/1,612 sputum samples that were culture negative for M. tuberculosis (specificity, 98.9%; 95% CI, 98.2, 99.3). For specimens positive for M. tuberculosis by MTBDRplus, this assay's sensitivity and specificity for rifampin resistance were 85.7% (95% CI, 57.2, 98.2) and 96.6% (95% CI, 93.2, 98.6) and for isoniazid resistance they were 62.1% (95% CI, 42.3, 79.3) and 97.9% (95% CI, 94.8, 99.4). For sputum testing, the sensitivity of MTBDRplus is directly related to the specimen's bacillary burden. Our results support recommendations that the MTBDRplus test not be used for direct testing of smear-negative or paucibacillary sputum samples