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Contains fulltext : 293771.pdf (Publisher’s version ) (Open Access)

Item does not contain fulltext, BACKGROUND: Postural abnormalities involving the trunk are referred to as axial postural abnormalities and can be observed in over 20% of patients with Parkinson's disease (PD) and in atypical parkinsonism. These symptoms are highly disabling and frequently associated with back pain and a worse quality of life in PD. Despite their frequency, little is known about the pathophysiology of these symptoms and scant data are reported about their clinical predictors, making it difficult to prompt prevention strategies. OBJECTIVES: We conducted a scoping literature review of clinical predictors and pathophysiology of axial postural abnormalities in patients with parkinsonism to identify key concepts, theories and evidence on this topic. METHODS: We applied a systematic approach to identify studies, appraise quality of evidence, summarize main findings, and highlight knowledge gaps. RESULTS: Ninety-two articles were reviewed: 25% reported on clinical predictors and 75% on pathophysiology. Most studies identified advanced disease stage and greater motor symptoms severity as independent clinical predictors in both PD and multiple system atrophy. Discrepant pathophysiology data suggested different potential central and peripheral pathogenic mechanisms. CONCLUSIONS: The recognition of clinical predictors and pathophysiology of axial postural abnormalities in parkinsonism is far from being elucidated due to literature bias, encompassing different inclusion criteria and measurement tools and heterogeneity of patient samples. Most studies identified advanced disease stage and higher burden of motor symptoms as possible clinical predictors. Pathophysiology data point toward many different (possibly non-mutually exclusive) mechanisms, including dystonia, rigidity, proprioceptive and vestibular impairment, and higher cognitive deficits., 01 november 2023

In Australia, fungi associated with larvae of the biological control agent Cactoblastis cactorum may contribute to the control of the exotic weed pricklypear (Opuntia inermis). C. cactorum larvae were assessed for their ability to vector pathogenic fungi into O. inermis by the infestation of larvae with fungal suspensions. Six fungal isolates caused disease after being carried into the host on external surfaces of larvae, and propagules of one isolate (UQ5109) initiated disease after being transferred from the cladode epidermis into the host by larvae feeding on the plant. Scanning electron microscopy revealed extensive hyphal growth on the external surfaces of larvae infested with several of the isolates. Fungi isolated from field-grown O. inermis cladodes were tested for pathogenicity to this plant in an in vivo plant assay. In total, 152 isolates were screened, 22 of which infected the host in pathogenicity tests. Only 1 (UQ5115) infected undamaged host tissue, whereas the remainder required the host to be wounded before infection could proceed. The majority of isolates were only weakly pathogenic, even when inoculated via wounds, suggesting that most were either saprophytes or weak parasites. This study demonstrates that it is possible for larvae of C. cactorum to transmit fungal pathogens into O. inermis tissue and it has provided a sound basis for future field work to determine the contribution that fungi make to the control of O. inermis.

The incidence and severity of fusarium wilt of cotton in glasshouse trials increased when levels of plant residue in the soil were increased by the incorporation of whole cotton plants (6-week-old seedlings dried out for a further 6 weeks) into the soil. In non-residue-supplemented potting mix, disease incidence was <50%, but ranged from 74 to >90% in residue-supplemented potting mix. The disease was significantly affected by soil microflora and soil type, but not affected by soil pH in the range 4.0–8.5. Although the same amount of inoculum was added to both autoclaved and untreated soils, the disease was less severe in autoclaved soils than in untreated soils regardless of soil type. Among the 4 clay soils investigated, the disease was less severe in a grey sandy clay and a brown heavy clay than in a dark grey heavy clay. Compared with the soils collected at the end of the 1995–96 growing season, the disease became more severe in the soil of plots planted to the most susceptible cotton cultivar Siokra 1-4, but less severe in the soil of plots planted to the less susceptible cotton cultivar DP90 at the end of the 1996–97 growing season. However, no significant differences were observed in the soil of plots planted to cotton cultivar Siokra L22, sorghum, maize or soybean.

Fusarium wilt, caused by Fusarium oxysporum f. sp. vasinfectum, is a new and important disease of cotton in Australia. Some factors affecting either the infection process or the subsequent development of symptoms under glasshouse conditions were examined in this study. The pathogenicity of inocula was significantly affected by the media in which they were produced. The most severe symptoms developed in the plants inoculated with the inoculum produced in Komada-Ezuka liquid medium, in which glucose and L-asparagine were used as the carbon and nitrogen source, respectively. Symptoms were significantly more severe in plants inoculated with the inocula suspended in culture filtrates than in those inoculated with the inocula suspended in distilled water, indicating that fungal metabolites played an important role in the infection process. The disease was enhanced by high conidial concentration (>1.0 x 106 conidia/mL), slightly acidic inoculum (pH 4.0–5.5) and longer inoculation period (5–25 min). One-week-old seedlings were most susceptible, regardless of cultivar, and the resistance of plants increased with their age. The development of symptoms was enhanced at a moderate temperature range (18–23°C), but suppressed at a higher temperature range (28–33°C). Based on these results, an optimised procedure of pathogenicity assay is described.

During the 1995–96 growing season, the effects of fertiliser application and growth of different crops on the population of Fzrsarium oxysporum f. sp, vasinfictum (Fov) in field soils were examined. In soil samples collected 35 days after fertiliser application, densities of Fov were significantly lower in soils receiving 180 units of anhydrous ammonia than in those receiving 40 or 180 units of urea. When compared with samples collected at sowing, densities of Fov were significantly reduced in soil samples from plots planted to either the less susceptible cotton cultivar DP90 or soybean. The proportions of Fov in the total F: oxysporum population increased significantly in soils planted to the most susceptible cotton cultivar Siokra 1–4, but decreased significantly in soils planted to the less susceptible cultivar DP90.