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1.
Molecules ; 25(14)2020 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-32668802

RESUMO

Calluna vulgaris (heather) is an aggressive invasive weed on the Central Plateau, North Is., New Zealand (NZ), where it encounters different environmental factors compared to its native range in Europe, such as high ultraviolet radiation (UV) and a lack of specialist herbivores. The specialist herbivore Lochmaea suturalis (heather beetle) was introduced from the United Kingdom (UK) in 1996 as a biocontrol agent to manage this invasive weed. Like other plant invaders, a novel environment may be challenging for heather as it adjusts to its new conditions. This process of "adjustment" involves morphological and physiological changes often linked to phenotypic plasticity. The biochemical responses of exotic plants to environmental variables in their invaded range is poorly understood. The production and release of volatile organic compounds (VOCs) is essential to plant communication and highly susceptible to environmental change. This study therefore aimed to explore the VOC emissions of heather in response to different levels of UV exposure, and to feeding damage by L. suturalis. Using tunnel houses clad with UV-selective filters, we measured VOCs produced by heather under NZ ambient, 20% attenuated, and 95% attenuated solar UV treatments. We also compared VOC emissions in the field at adjacent sites where L. suturalis was present or absent. Volatiles produced by the same target heather plants were measured at four different times in the spring and summer of 2018-2019, reflecting variations in beetle's abundance, feeding stage and plant phenology. Heather plants under 95% attenuated UV produced significantly higher amounts of (E)-ß-farnesene, decanal, benzaldehyde, and benzeneacetaldehyde compared to 25% attenuated and ambient UV radiation. We also found significant differences in volatiles produced by heather plants in beetle-present versus beetle-absent sites on most sampling occasions. We also recorded a lower number of generalist herbivores on heather at sites where L. suturalis was present. Interactions between invasive plants, a novel environment, and the native communities they invade, are discussed.


Assuntos
Calluna/metabolismo , Calluna/efeitos da radiação , Herbivoria , Plantas Daninhas/metabolismo , Plantas Daninhas/efeitos da radiação , Compostos Orgânicos Voláteis/metabolismo , Animais , Agentes de Controle Biológico , Besouros , Nova Zelândia , Estresse Fisiológico , Raios Ultravioleta
2.
Gen Comp Endocrinol ; 244: 86-92, 2017 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-26801581

RESUMO

Plasma corticosterone concentrations increase when birds experience a stressor, and plasma corticosterone responses to a capture and handling stressor have been measured in many species of birds. Whilst it is assumed that the reported corticosterone responses reflect the inherent sensitivity of each bird to the stressor, responses of the same birds have rarely been measured at intervals of one or more years. The current study was conducted to measure the repeatability in two successive years of corticosterone responses of little penguins (Eudyptula minor) at Oamaru, New Zealand. There was a wide range of individual corticosterone responses to capture and restraint in 96 little penguins in 2012 and 50 penguins sampled at the same time of year in 2013. There were significant repeatabilities for the ranks of corticosterone at 15, 30 and 60min (r=0.416±0.160, r=0.636±0.115 and r=0.380±0.166 respectively) and for the ranks of integrated corticosterone responses (r=0.594±0.126) for 23 birds sampled in both years. There were no significant relationships between the size of corticosterone responses and age, body weight or condition index. Mean corticosterone concentrations at 60min were 114.22±6.65ng/ml in 2012 and 116.94±6.42ng/ml in 2013. Mean corticosterone responses did not differ between two successive years and were greater than responses of other penguin species. Penguins are well suited to long term studies in which corticosterone responses are measured annually as potential measures of changing marine environmental conditions.


Assuntos
Corticosterona/sangue , Spheniscidae/metabolismo , Animais , Nova Zelândia , Fatores de Tempo
3.
Int J Sport Nutr Exerc Metab ; 25(6): 541-9, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26008634

RESUMO

Sprint interval training (SIT), repeated bouts of high-intensity exercise, improves skeletal muscle oxidative capacity and exercise performance. ß-alanine (ß-ALA) supplementation has been shown to enhance exercise performance, which led us to hypothesize that chronic ß-ALA supplementation would augment work capacity during SIT and augment training-induced adaptations in skeletal muscle and performance. Twenty-four active but untrained men (23 ± 2 yr; VO2peak = 50 ± 6 mL · kg(-1) · min(-1)) ingested 3.2 g/day of ß-ALA or a placebo (PLA) for a total of 10 weeks (n = 12 per group). Following 4 weeks of baseline supplementation, participants completed a 6-week SIT intervention. Each of 3 weekly sessions consisted of 4-6 Wingate tests, i.e., 30-s bouts of maximal cycling, interspersed with 4 min of recovery. Before and after the 6-week SIT program, participants completed a 250-kJ time trial and a repeated sprint test. Biopsies (v. lateralis) revealed that skeletal muscle carnosine content increased by 33% and 52%, respectively, after 4 and 10 weeks of ß-ALA supplementation, but was unchanged in PLA. Total work performed during each training session was similar across treatments. SIT increased markers of mitochondrial content, including cytochome c oxidase (40%) and ß-hydroxyacyl-CoA dehydrogenase maximal activities (19%), as well as VO2peak (9%), repeated-sprint capacity (5%), and 250-kJ time trial performance (13%), but there were no differences between treatments for any measure (p < .01, main effects for time; p > .05, interaction effects). The training stimulus may have overwhelmed any potential influence of ß-ALA, or the supplementation protocol was insufficient to alter the variables to a detectable extent.


Assuntos
Músculo Esquelético/fisiologia , Condicionamento Físico Humano , Fenômenos Fisiológicos da Nutrição Esportiva , beta-Alanina/administração & dosagem , Adaptação Fisiológica , Adulto , Carnosina/química , Suplementos Nutricionais , Método Duplo-Cego , Exercício Físico/fisiologia , Teste de Esforço , Humanos , Masculino , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/fisiologia , Músculo Esquelético/efeitos dos fármacos , Consumo de Oxigênio , Adulto Jovem
4.
Bull Environ Contam Toxicol ; 93(4): 452-5, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25100182

RESUMO

The earthworm Eisenia fetida was exposed to artificial soil supplemented with 18-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane) to investigate its effects on earthworm mortality, growth, avoidance, burrowing behavior and respiration. The results revealed that 18-crown-6 had the potential to negatively affect the behavior of earthworms. The 7-d LC50 was 585 mg kg(-1) soil. Avoidance behavior was the most sensitive endpoint, with a 48-h EC50 of 120 mg kg(-1) soil. Growth, burrow length and respiration showed general decreases with increasing 18-crown-6 concentrations. Behavioral endpoints and respiration may be regarded as sensitive parameters in evaluating the toxicity of this chemical to earthworms.


Assuntos
Éteres de Coroa/toxicidade , Oligoquetos/efeitos dos fármacos , Poluentes do Solo/toxicidade , Análise de Variância , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Comportamento Animal/efeitos dos fármacos , Dose Letal Mediana , Oligoquetos/crescimento & desenvolvimento , Consumo de Oxigênio/efeitos dos fármacos
5.
Zoo Biol ; 32(5): 541-8, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24018906

RESUMO

Avian growth rate patterns represent a trade off between a tissue's functional maturity and its capacity for growth. At the time of hatch, the brown kiwi (Apteryx mantelli) limb has a high level of maturity in order for the chick to be able to kick its way out of the shell and walk and forage independently from an early age. Growth curves of limb segments, bill length and bodyweight are presented for captive-reared, BNZ Operation Nest Egg™ chicks over a period of 3 months from the point of hatch. Some parameters were slightly larger in the females than in males at time of hatch, including the bill length. Growth in bodyweight began to slow earlier in males than in females. Regressions of limb and bill measurements over time showed linear patterns of growth instead of a sigmoidal curve as seen in other birds, probably due to the short period of observation. Bodyweight and bill length were then compared to these morphometrics in a wild population of kiwi. Captive-reared chicks were found to hatch with shorter bills and to increase in bodyweight at a faster rate than the wild birds. Rapid weight gain has been implicated in developmental limb deformities in other precocial and long-legged birds and should be avoided in captive kiwi.


Assuntos
Animais de Zoológico , Tamanho Corporal/fisiologia , Paleógnatas/crescimento & desenvolvimento , Fatores Etários , Animais , Bico/crescimento & desenvolvimento , Pesos e Medidas Corporais , Feminino , Masculino , Fatores Sexuais
6.
Theriogenology ; 208: 77-87, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37302246

RESUMO

While captivity-related stress and the associated rise in baseline glucocorticoid (GC) concentrations have been linked to ovarian quiescence in some felid species, no study has examined the effects of elevated GC on oocyte quality. This study examined the effects of exogenous GC administration on the ovarian response and oocyte quality of domestic cats after an ovarian stimulation protocol. Entire mature female cats were divided into treatment (n = 6) and control (n = 6) groups. Cats in the GC treatment (GCT) group were given 1 mg kg-1 oral prednisolone daily from Day 0-45. All cats (n = 12) were given 0.088 mg kg-1 day-1 progesterone orally from Day 0-37, before treatment with 75 IU eCG im to induce follicular growth on Day 40, followed by 50 IU hCG im 80 h later to induce ovulation. Cats were ovariohysterectomised 30 h after the hCG treatment. Blood samples were collected on Days 0, 10, 30 and 40 (prior to eCG treatment), 80 h after eCG treatment, and on Day 45 for cortisol, glucose, prednisolone, oestradiol, and progesterone analysis. Cortisol concentrations did not differ between treatment groups throughout the study. Mean glucose concentrations were higher in the GCT cats (P = 0.004). Prednisolone was undetectable in all samples. Oestradiol and progesterone concentrations confirmed that the eCG treatment stimulated follicular activity and ovulation in all cats. Following ovariohysterectomy, the ovarian responses were graded (1 = excellent, 4 = poor) and oocytes retrieved from the oviducts. Each oocyte was given a total oocyte score (TOS: using an 9-point scale, 8 = best) based on four parameters: oocyte morphology, size, ooplasm uniformity and granularity, and zona pellucida (ZP) thickness and variation. Ovulation was confirmed in all cats, with a mean of 10.5 ± 1.1 ovulations per cat. Ovarian mass, ovarian response, number of ovulations, and oocyte recovery did not differ between groups. Oocyte diameter did not differ between the groups, but the ZP was thinner in the GCT group (3.1 ± 0.3 µm vs. 4.1 ± 0.3 µm, P = 0.03). The TOS was similar between treatment and control cats, but the ooplasm grade was lower (1.5 ± 0.1 vs. 1.9 ± 0.1, P = 0.01) and there was a tendency for ZP grade to be poorer (0.8 ± 0.1 vs. 1.2 ± 0.2; P = 0.08) in the treatment group. In conclusion, the GC treatment resulted in morphological changes to oocytes collected following ovarian stimulation. Whether these changes would affect fertility warrants further investigation.


Assuntos
Glucocorticoides , Hidrocortisona , Feminino , Gatos , Animais , Glucocorticoides/farmacologia , Progesterona , Oócitos , Prednisolona/farmacologia , Estradiol , Glucose
7.
Theriogenology ; 179: 237-244, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34896746

RESUMO

Accurate and reliable monitoring of ovarian activity is challenging in many felids as current methods are either invasive or not amenable to real-time assessments. This 45-day study assessed whether accelerometry and infrared (IR) thermography can be used to address these limitations. Intact female domestic cats (n = 12) were given 0.088 mg kg-1 day-1 altrenogest (progestin) orally for 37 days to suppress follicular growth. On Day 40, cats were given 75 IU eCG im to induce follicular growth and 50 IU hCG im 80 h later to induce ovulation. Cats were ovariohysterectomised 30-31 h after the hCG treatment. Actical® accelerometers were fitted to the cats' collars and activity monitored continuously from the start of the altrenogest treatment until ovariohysterectomy. Infrared images of the perivulvar, perianal, and gluteal area were taken of each cat on Day 30 and daily from Days 36-45 of the study. Perivulvar temperature (PVT), PVT relative to gluteal temperatures (PVT-GT), and PVT relative to perianal temperature (PVT-PAT) were recorded for each image. Blood samples were collected on Days 0, 10, 30, and 40, immediately prior to the hCG treatment, and at the time of ovariohysterectomy. Serum oestradiol and progesterone concentrations indicated complete ovarian suppression by Day 30 and, together with morphological assessment of the ovaries, confirmed the induction of follicular growth and ovulation in all cats. Daily activity counts differed among cats (P < 0.001), so the daily activity counts of each cat were converted to a proportional change from the average daily activity count from Days 30-39 (defined as the 'proportional daily activity'). Proportional daily activity counts increased after the stimulation of follicular growth with eCG, with peak levels (2.03 ± 0.29-fold higher than pre-treatment levels; P = 0.006) occurring three days after the eCG treatment. The PVT-GT showed the greatest sensitivity to detect subtle changes in body temperature, increasing from early to late follicular growth (1.96 ± 0.33 °C increase from Day 41-43; P < 0.001) and decreasing after hCG-induced ovulation (1.24 ± 0.41 °C decrease from Day 43-45; P = 0.01). In conclusion, both accelerometry and IR thermography show potential as non-invasive, real-time methods for assessing ovarian activity in cats, but further research is required to determine if these methods could be used to monitor natural/non-stimulated oestrous cycles.


Assuntos
Gonadotropina Coriônica , Ovário , Acelerometria/veterinária , Animais , Gatos , Estradiol , Feminino , Ovário/diagnóstico por imagem , Ovulação , Termografia/veterinária
8.
Theriogenology ; 189: 20-30, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-35714522

RESUMO

Elevated glucocorticoid (GC) concentrations associated with captivity-related stress have been linked to impaired testicular function and low sperm quality in felids, but direct physiological evidence is lacking. This study assessed the effects of exogenous GC treatment on felid testicular function using the domestic cat (Felis catus) as a model species. Sixteen intact male cats aged 2.4 ± 0.8 years (mean ± SEM) were divided randomly into treatment (n = 8) and control (n = 8) groups. Treatment cats were given 1 mg kg-1 oral prednisolone daily for 50 days. Blood samples were taken on Days 0 (first prednisolone treatment), 2, 4, 7, 10, 20, 30, 40, 50 (prior to neutering) and 60 of the trial. All cats were orchiectomised on day 50, epididymal sperm assessed, and the testes fixed for histological assessment. Testosterone concentrations did not differ between the two groups. While sperm motility was similar between the treatment and control groups, cats given prednisolone had a higher proportion of morphologically abnormal sperm in both the caput (72.5% vs. 59.6%, P < 0.001) and cauda (56.7% vs. 35.8%, P < 0.001) epididymis. Testicular histomorphometric data and total number of germ cells per seminiferous tubule cross section did not differ between groups, nor did the relative abundance of spermatogonia, spermatocytes, and spermatids. Cats given prednisolone had fewer Sertoli cells per tubule cross-section than those in the control group (17.1 ± 0.9 vs. 19.7 ± 0.8, P = 0.04), which was likely related to higher rates of Sertoli cell apoptosis in treatment versus control cats (0.25 ± 0.02 vs. 0.10 ± 0.02 apoptotic Sertoli cells per tubule, respectively; P < 0.001). Sertoli cell load (number of germ cells per Sertoli cell) was also higher in the treatment group than in the control group (11.5 ± 0.8 vs. 9.4 ± 1.2 germ cells per Sertoli cell, respectively; P < 0.001), and was positively correlated with the percentage of morphologically abnormal sperm in the epididymis (r2 = 0.78, P < 0.001). Prednisolone treatment resulted in an increase in the proportion of abnormal sperm in the epididymis, which may be explained by an increased nurturing demand on a reduced Sertoli cell population. These findings provide novel evidence to support the hypothesis that elevated GC concentrations, such as those resulting from captivity-related stress, have the potential to impair testicular function and sperm quality in felids.


Assuntos
Epididimo , Células de Sertoli , Animais , Gatos , Epididimo/fisiologia , Glucocorticoides/farmacologia , Masculino , Prednisolona/farmacologia , Sêmen , Células de Sertoli/fisiologia , Motilidade dos Espermatozoides/fisiologia , Espermátides , Espermatogênese/fisiologia , Espermatozoides/fisiologia , Testículo
9.
Mol Genet Metab ; 104(4): 620-6, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22001501

RESUMO

GM1 gangliosidosis, a neurodegenerative disorder, and Morquio B disease, a skeletal disorder, are lysosomal storage disorders caused by inherited defects in the enzyme ß-galactosidase (GLB1; EC 3.1.2.23; MIM #611458). Enzyme replacement therapy (ERT), a standard of care for a number of non-neuronopathic lysosomal storage disorders, is not yet available for GLB1 deficiency. Although functionally active recombinant human and feline GLB1 precursors have been purified, ERT has not yet been demonstrated in GM1 gangliosidosis or Morquio B disease models. A major obstacle to developing effective therapy may be the stability of human GLB1. We show here that mouse GLB1 has greater stability when compared to human GLB1, and that human GLB1 activity is temperature and protective-dependent on protein cathepsin A, while that of mouse GLB1 is not. These findings may impact on the eventual development of ERT for GLB1 deficiency. Despite our attempts to improve the extracellular stability of human GLB1 through sequence modification and the use of chemical chaperone N-butyldeoxygalactonojirimycin, the specific enzyme activity remained well below that of mGLB1.


Assuntos
Catepsina A/deficiência , Proteínas Recombinantes de Fusão/química , beta-Galactosidase/química , 1-Desoxinojirimicina/análogos & derivados , 1-Desoxinojirimicina/química , Animais , Catepsina A/metabolismo , Extratos Celulares/química , Células Cultivadas , Ativadores de Enzimas/química , Ensaios Enzimáticos , Estabilidade Enzimática , Humanos , Camundongos , Engenharia de Proteínas , Proteínas Recombinantes de Fusão/metabolismo , beta-Galactosidase/metabolismo
10.
Front Plant Sci ; 12: 734531, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34721463

RESUMO

Volatile organic compounds (VOCs) produced by plants are essential indicators of their physiological response to environmental conditions. But evidence of natural variation in VOC emissions and their contributing factors is still limited, especially for non-cultivated species. Here we explored the natural volatile emissions of Dracophyllum subulatum Hook.f., an endemic shrub to the North Island Central Plateau of New Zealand, and determined some environmental factors driving the plant's emissions. Volatile emissions of D. subulatum were measured on four separate occasions from December 2017 to September 2018 using the "push-pull" headspace sampling technique and analyzed using gas chromatography-mass spectrometry (GC-MS). D. subulatum was classified based on the volatiles measured on each sampling occasion using linear discriminant analysis (LDA). On each sampling occasion, we also recorded and compared ambient air temperature, herbivory damage, total soil nitrogen (N), available phosphorus (P), potassium (K), and soil moisture content. The relationship between environmental variables that differed significantly between sampling occasions and volatile emissions were estimated using generalized linear models (GLMs). Based on VOCs measured on each sampling occasion, we were able to distinguish different chemical profiles. Overall, we found that total emission and the relative proportions of all major chemical classes released by D. subulatum were significantly higher during summer. The GLMs reveal that differences in environmental factors between the four sampling occasions are highly associated with changing emissions. Higher temperatures in summer had a consistently strong positive relationship with emissions, while the impacts of soil moisture content, P and K were variable and depended on the chemical class. These results are discussed, particularly how high temperature (warming) may shape volatile emissions and plants' ecology.

11.
Zoo Biol ; 29(5): 537-50, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-19816904

RESUMO

The ingredients and the macro- and micro-nutrient contents of diets that are fed to captive kiwi at seven New Zealand holding facilities were subject to analysis. The nutrient compositions were compared across facilities and with an estimate of the nutrient composition of the diets of wild kiwi based on the intake of various dietary ingredients reported in the literature. A total of 20 ingredients were used, the number and proportion of these ingredients varied greatly between facilities. Six of the diets were based primarily on meat and three comprised a mixture of meat and cat biscuits. Just one included a proprietary insectivore mix. Nutrient content varied greatly between the seven diets, organic matter ranging from 91.8 to 95.6%, crude protein from 41.9 to 62.9%, and crude fat from 9.0 to 28.7% of dry matter content. Large variations were found in the total content and profile of amino acids and of fatty acids of the diets. The nutrient content of all seven diets differed from that of the natural diet of wild kiwi. Hence, the presence of nutrient deficiencies in the current formulations cannot be excluded.


Assuntos
Ração Animal/análise , Animais de Zoológico , Dieta/veterinária , Paleógnatas/fisiologia , Animais , Carboidratos da Dieta/análise , Gorduras na Dieta/análise , Proteínas Alimentares/análise , Ácidos Graxos/análise , Minerais/análise , Valor Nutritivo
12.
Theriogenology ; 157: 245-253, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32818882

RESUMO

Reliable detection and monitoring of estrus and pregnancy is essential to the effective ex situ conservation of endangered felids. Here, we review the current methods used to detect estrus and pregnancy in felids and describe the advantages and limitations of each. A total of 194 felid-focused publications were reviewed. The methods used included behavioral assessments (61 publications across 24 species), hormone monitoring (124 studies across 28 species), fecal protein monitoring (two studies in cheetah), ultrasonography (31 publications across seven species), vaginal cytology (22 publications across nine species), and laparoscopy (70 publications across 19 species). Behavior-based assessments of reproductive state are often inconsistent and unreliable in felids; thus hormone measurement is the most frequently used method for monitoring estrous cycles (66% of studies). In non-domestic felids, non-invasive fecal- or urine-based hormone metabolite analyses are preferred to blood assessments (66% of endocrine-based publications). While the measurement of fecal estrogen and progestin metabolites are useful for the retrospective assessment of ovarian activity, their use for real-time detection of estrus is limited. Vaginal cytology, laparoscopy and ultrasonography provide an acute and immediate determination of reproductive state but usually require anesthesia or sedation, which can prevent ovulation and cause abortions; thus, their use for pregnancy diagnosis is limited. Fecal progesterone or prostaglandin F2α metabolites can be used to detect pregnancy in most felids (the exception being fecal progestins for Lynx spp.), but only during mid-to-late gestation. Urinary relaxin measurement is a promising method for earlier pregnancy diagnosis (30-40% duration of gestation) but is presently limited by poor assay sensitivity due to the lack of a feline-specific relaxin antibody. Elevated levels of fecal immunoglobulin J chain have been investigated as a tool to detect pregnancy in cheetah (>80% accuracy), but research is lacking on other species. We conclude that there is no single 'best method' for monitoring ovarian activity and detecting pregnancy in felids, and current best practice would involve a combination of existing methods. Non-invasive methods for detecting estrus and pregnancy in felids (e.g., accelerometry and infrared thermography) should also be considered to augment existing methods.


Assuntos
Ciclo Estral , Felidae , Reprodução , Animais , Gatos , Fezes , Feminino , Gravidez , Progesterona , Estudos Retrospectivos
13.
Plants (Basel) ; 9(7)2020 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-32698536

RESUMO

Heather (Calluna vulgaris) and broom (Cytisus scoparius), originally from Europe, are the main invasive plants on New Zealand's North Island Central Plateau, where they threaten native flora and fauna. Given the strong link between arthropod communities and plants, we explored the impact of these invasive weeds on the diversity and composition of associated arthropod assemblages in this area. The arthropods in heather-invaded areas, broom-invaded areas, and areas dominated by the native species manuka (Leptospermum scoparium) and Dracohyllum (Dracophyllum subulatum) were collected and identified to order. During summer and autumn, arthropods were collected using beating trays, flight intercept traps and pitfall traps. Diversity indices (Richness, Shannon's index and Simpson's index) were calculated at the order level, and permutational multivariate analysis (PERMANOVA) was used to explore differences in order-level community composition. Our results show a significant variation in community composition for all trapping methods in both seasons, whereas invasive plants did not profoundly impact arthropod order richness. The presence of broom increased arthropod abundance, while heather was linked to a reduction. Under all possible plant pairings between heather, broom, manuka, and Dracophylum, the impact of neighbouring plant identity on arthropod community composition was further explored for the samples collected using beating trays. The results suggest that during plant invasion, arthropod communities are affected by neighbouring plant identity and that impacts vary between arthropod sampling methods and seasons.

14.
Sci Rep ; 10(1): 11736, 2020 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-32678113

RESUMO

The New Zealand tea tree Leptospermun scoparium (manuka) is widely known for the antimicrobial properties of its honey. Manuka is native to New Zealand, growing in a range of environments, including the Central Volcanic Plateau of the North Island, where it is currently threatened by the spread of exotic invasive weeds such as heather (Calluna vulgaris) and Scotch broom (Cytisus scoparius). Here, we characterise for the first time the aboveground volatile organic compounds (VOCs) produced by manuka in this area, during summer and winter seasons, in weed-invaded and non-invaded stands. We measured plant volatiles at four sites, each with a distinct combination of woody species: (1) conspecific stands of manuka; (2) manuka and another native species (Dracophyllum subulatum); and manuka with one of two European invasive plants, (3) heather or (4) Scotch broom. We also quantified herbivore damage on target manuka plants and analysed microclimatic variables (soil nutrients, air temperature and soil water content) to investigate their impact on volatile emissions. Our results reveal a strong seasonal effect on volatile emissions, but also significant differences between sites associated with biotic and abiotic changes partly driven by invasive plants. Overall, volatile emission rates from manuka were typically lower at sites where invaders were present. We point to several factors that could contribute to the observed emission patterns and areas of interest for future research to provide a comprehensive understanding of VOC emissions in nature. Given the vital role of volatile compounds in plant communication, we also recommend future studies to be performed in multiple seasons, with larger sample sizes and more study sites to expand on these findings and explore the ecological impacts of changes in VOC emissions during plant invasion.


Assuntos
Meio Ambiente , Leptospermum/química , Plantas Daninhas , Estações do Ano , Compostos Orgânicos Voláteis , Análise de Variância , Herbivoria , Nova Zelândia
15.
Plants (Basel) ; 9(2)2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-32098163

RESUMO

Invasive plants pose a threat to natural ecosystems, changing the community composition and ecological dynamics. One aspect that has received little attention is the production and emission of volatile organic compounds (VOCs) by invasive plants. Investigating VOCs is important because they are involved in vital ecological interactions such as pollination, herbivory and plant competition. Heather, Calluna vulgaris, is a major invasive weed in New Zealand, especially on the Central Plateau, where it has spread rapidly since its introduction in 1912, outcompeting native species. However, the chemical behaviour of heather in its invaded ranges is poorly understood. We aimed to explore the natural variation in volatile emissions of heather and the biotic and abiotic factors influencing them on the Central Plateau of New Zealand. To this end, foliar volatiles produced by heather at four different sites were collected and analysed using gas chromatography coupled to mass spectrometry. Soil properties, herbivory and other environmental data were also collected at each site to investigate their effects on VOC emissions using generalised linear models (GLMs). Our results reveal significant differences in VOC emissions between sites and suggest that soil nutrients are the main factor accounting for these differences. Herbivory and temperature had only a minor effect, while soil water content had no impact. Further studies are needed to investigate how these variations in the invasive plant's foliar volatiles influence native species.

16.
Biomacromolecules ; 10(6): 1365-73, 2009 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-19397289

RESUMO

Self-cross-linkable polyelectrolyte pairs comprised of poly(methacrylic acid, sodium salt-co-2-[methacryloyloxy]ethyl acetoacetate) (70:30 mol ratio, A70) and poly-L-lysine are incorporated into CaAlg beads to form either a covalently cross-linked shell or a core-cross-linked bead. In both cases the reactive polyanion is added to a solution of sodium alginate that may contain live cells and dropped into a calcium chloride gelling bath. Subsequent exposure to poly-L-lysine (15-30 kDa) leads to formation of a cross-linked shell, while exposure to lower molecular weight poly-L-lysine (4-15 kDa) leads to formation of an interpenetrating matrix of covalently cross-linked synthetic polymer within the CaAlg template. The resulting spherical composites are resistant to chemical and mechanical stress yet remain cyto-compatible. This approach to cell-encapsulation may be useful for cell immuno-isolation in therapeutic cell transplants.


Assuntos
Alginatos/química , Cápsulas , Animais , Linhagem Celular , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Camundongos , Permeabilidade , Polímeros/química , Rodaminas/química
17.
Gen Comp Endocrinol ; 163(1-2): 158-68, 2009 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-19351536

RESUMO

Plasma corticosterone concentrations increase when birds experience a stressor, and in this study we quantified variation in corticosterone responses for the first time in a species of free-living bird. Adelie penguins (Pygoscelisadeliae) nesting at Cape Bird on Ross Island in Antarctica were sampled on three occasions. Penguins with relatively low or high corticosterone responses on the first occasion had consistently low or high responses, as previously found for great tits and chickens. A model for birds is proposed in which birds with low corticosterone responses and proactive personalities are likely to be more successful (have greater fitness) in constant or predictable conditions, whilst birds with reactive personalities and high corticosterone responses will be more successful in changing or unpredictable conditions. There is thus no linear relationship between the size of a corticosterone response and fitness. Whilst the absolute magnitude of corticosterone responses varies markedly across species of birds, coefficients of variation are similar. Individual corticosterone responses are generally repeatable, with significant statistical repeatabilities for 30 min corticosterone concentrations and integrated corticosterone concentrations in the Adelie penguin, great tit and chicken. Coefficients of variation in corticosterone responses between birds and power analyses were used to provide a rule of thumb for determining differences between groups of birds in mean corticosterone concentrations to enable statistical analyses to have acceptable levels of statistical power for given sample sizes. It is suggested that power analyses and this rule of thumb be adopted in future investigations of corticosterone responses in birds.


Assuntos
Aves/fisiologia , Corticosterona/fisiologia , Spheniscidae/fisiologia , Animais , Comportamento Animal/fisiologia , Corticosterona/sangue , Interpretação Estatística de Dados , Feminino , Masculino , Estresse Fisiológico
18.
Artigo em Inglês | MEDLINE | ID: mdl-19922164

RESUMO

MDCK cells were engineered to express luciferase driven by cytomegalovirus (CMV) or hybrid ubiquitin B (UbB) promoter and encapsulated in alginate-poly-L-lysine-alginate microcapsules. In vitro experiments showed capsules could be monitored individually or in multi-layers quantitatively. When luciferase-expressing and non-luciferase expressing MDCK cells were mixed at different ratios and encapsulated, the signals increased linearly according to the number of capsules, in vitro and in vivo. For CMV-driven luciferase expression, the strongest signal was seen at 4 hours post-implantation, with a subsequent 50% decrease by 24 hours and then declined gradually to 10-20% until day 20. However, retrieved capsules showed good cell viability. When capsules contained plasmid driven by UbB promoter, there was no decline in signal. Our results indicate that luciferase could be used as a marker for microencapsulated cells to monitor the viability and gene expression of the implanted cells.


Assuntos
Cápsulas/química , Transplante de Células/métodos , Terapia Genética/métodos , Luciferases/administração & dosagem , Luciferases/genética , Alginatos , Animais , Cápsulas/uso terapêutico , Linhagem Celular , Sobrevivência Celular , Cães , Técnicas de Transferência de Genes , Genes Reporter , Vetores Genéticos , Implantes Experimentais , Luciferases/biossíntese , Camundongos , Camundongos Endogâmicos BALB C , Farmacocinética , Polilisina/análogos & derivados
19.
Adolesc Health Med Ther ; 10: 15-19, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30863194

RESUMO

In this report, we document the discussions and recommendations of a national conference designed to create a coalition to tackle adolescent idiopathic scoliosis (AIS) held on June 6 and 7, 2017 in Hamilton, ON, Canada. The goal of the establishment of this coalition is to join the efforts of patients, parents, physicians, researchers and other stakeholders to identify stakeholders' perspectives and to categorize gaps in knowledge and target further AIS research and clinical care priorities. The participants' main priorities included focus on shared decision making regarding clinical and research priorities between the stakeholders on the clinical, research and policy sides with patients and families. In addition, improvements in the dissemination of information via digital platforms and identification of cost-effective screening strategies that may help early identification and intervention were also recognized as a priority. Commitment was reached to form a national coalition to understand the determinants of this condition and enhance patient outcomes through improved clinical care and research efforts.

20.
Biomacromolecules ; 9(9): 2292-300, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18665640

RESUMO

Self-cross-linking polyelectrolytes are used to strengthen the surface of calcium alginate beads for cell encapsulation. Poly([2-(methacryloyloxy)ethyl]trimethylammonium chloride), containing 30 mol % 2-aminoethyl methacrylate, and poly(sodium methacrylate), containing 30 mol % 2-(methacryloyloxy)ethyl acetoacetate, were prepared by radical polymerization. Sequential deposition of these polyelectrolytes on calcium alginate films or beads led to a shell consisting of a covalently cross-linked polyelectrolyte complex that resisted osmotic pressure changes as well as challenges with citrate and high ionic strength. Confocal laser fluorescence microscopy revealed that both polyelectrolytes were concentrated in the outer 7-25 microm of the calcium alginate beads. The thickness of this cross-linked shell increased with exposure time. GPC studies of solutions permeating through analogous flat model membranes showed molecular weight cut-offs between 150 and 200 kg/mol for poly(ethylene glycol), suitable for cell encapsulation. C 2C 12 mouse cells were shown to be viable within calcium alginate capsules coated with the new polyelectrolytes, even though some of the capsules showed fibroid overcoats when implanted in mice due to an immune response.


Assuntos
Alginatos/química , Reagentes de Ligações Cruzadas/química , Reagentes de Ligações Cruzadas/farmacologia , Sistemas de Liberação de Medicamentos , Eletrólitos/química , Eletrólitos/farmacologia , Metacrilatos/química , Ácidos Polimetacrílicos/química , Acetoacetatos , Animais , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Ácido Cítrico/química , Reagentes de Ligações Cruzadas/síntese química , Desenho de Fármacos , Eletrólitos/síntese química , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Membranas Artificiais , Camundongos , Estrutura Molecular , Peso Molecular , Concentração Osmolar , Pressão Osmótica , Permeabilidade/efeitos dos fármacos , Polietilenoglicóis/química , Propriedades de Superfície
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