Grazing activity increases decomposition of yak dung and litter in an alpine meadow on the Qinghai-Tibet plateau

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In vivo Hypoxia and a Fungal Alcohol Dehydrogenase Influence the Pathogenesis of Invasive Pulmonary Aspergillosis

Currently, our knowledge of how pathogenic fungi grow in mammalian host environments is limited. Using a chemotherapeutic murine model of invasive pulmonary aspergillosis (IPA) and 1H-NMR metabolomics, we detected ethanol in the lungs of mice infected with Aspergillus fumigatus. This result suggests that A. fumigatus is exposed to oxygen depleted microenvironments during infection. To test this hypothesis, we utilized a chemical hypoxia detection agent, pimonidazole hydrochloride, in three immunologically distinct murine models of IPA (chemotherapeutic, X-CGD, and corticosteroid). In all three IPA murine models, hypoxia was observed during the course of infection. We next tested the hypothesis that production of ethanol in vivo by the fungus is involved in hypoxia adaptation and fungal pathogenesis. Ethanol deficient A. fumigatus strains showed no growth defects in hypoxia and were able to cause wild type levels of mortality in all 3 murine models. However, lung immunohistopathology and flow cytometry analyses revealed an increase in the inflammatory response in mice infected with an alcohol dehydrogenase null mutant strain that corresponded with a reduction in fungal burden. Consequently, in this study we present the first in vivo observations that hypoxic microenvironments occur during a pulmonary invasive fungal infection and observe that a fungal alcohol dehydrogenase influences fungal pathogenesis in the lung. Thus, environmental conditions encountered by invading pathogenic fungi may result in substantial fungal metabolism changes that influence subsequent host immune responses

Evaluation of sorghum, sudan-grass and pearl millet cultivars in Manawatu

Sorghum, sudan-grass and pearl millet are versatile summer forages able to be grazed or conserved as silage. However, there is little recently published information on the performance these crops in New Zealand. A trial was carried out at Massey University, Palmerston North, to compare forage yields and crop morphology of four sorghum x sudan-grass hybrids (Pac 8421, Pac 8423, Pacific BMR and Bettagraze), two sudan-grass (Superdan 2 and Sprint) and one pearl millet (Nutrifeed) cultivars sown on the 8 and 21 December 2009. At final harvest, 57 and 58 days after sowing for the first and second sowing dates respectively, dry matter yields decreased (P<0.005) with delayed sowing from 12,792 kg ha-1 to 11,356 kg ha-1. There were cultivar differences (P<0.0001) at both sowing dates. Mean yields (across sowing dates) ranged from 9,823 (Nutrifeed) to 13,953 kg DM ha-1 (Pac 8423). There was a significant interaction (P<0.0001) between sowing date and cultivar for yield at the second harvest; cultivar differences for the first sowing date were larger than for the second, which suffered more from cool autumn temperatures. There was a strong, positive, linear relationship between plant height at harvest and DM yield (R2 = 0.69). Mean leaf:stem ratio, for the first sowing (1.9), was significantly (P<0.001) higher than in the second sowing (1.8) and was influenced by cultivar.fals

Productivity and quality of kale, swede, fodder beet and maize in Manawatu

Winter grazing of forage crops can result in large losses of nitrogen (N) from leaching and consequently, deterioration in water quality in affected catchments. A viable alternative cropping option which can potentially reduce N leaching may be useful for maintaining productivity while minimising environmental risks. Maize could be a possible alternative crop because of its yield and low N as well as convenience to cut and carry system. Thus, maize, kale, swede and fodder beet were compared in a factorial randomised complete block design with or without N application. Dry matter (DM) yield ranged from 12,450 to 30,417 kg DM/ha with the highest yield achieved by maize hybrids. Yield was increased by N application, but there was no interaction between forage entries and N rates. Forage entries differed significantly in all quality traits while N application only affected crude protein (CP), soluble sugars and starch (SSS) and acid detergent fibre (ADF). Metabolisable energy (ME) was significantly different for all forage entries. It ranged from 9.5–11.0 MJ/kg DM for swede, fodder beet and maize and was <9.5 MJ/kg DM for kale. Maize hybrids showed the lowest CP (5.4–5.9%DM) and highest SSS (42.7– 48.0%DM). Dry matter yield was positively correlated with SSS (r = 0.58; P<0.001) and neutral detergent fibre (NDF) (r = 0.56; P<0.001). Similarly, ME was positively and strongly correlated with SSS (r = 0.79; P<0.001) while CP was negatively correlated with yield and all quality traits. The results highlight the advantages of maize having high DM yield and good feed quality under unlimited moisture conditions

Assessment of manuka provenances for production of high ‘unique manuka factor’ honey

Manuka (Leptospermum scoparium) honey with high methylglyoxal content, commonly expressed as unique manuka factor (UMF®) content, has strong antibacterial and anti-fungal properties. Consequently, there is a strong demand for high UMF manuka honey in the health food industry both in New Zealand and overseas. Currently manuka honey is produced from natural stands of manuka, but UMF content varies among regions. The active ingredient methylglyoxal is produced by natural chemical transformation of dihydroxyacetone (DHA) present in the nectar. Production of high UMF honey is insufficient to meet market demand; this is due to variation in UMF amongst stands causing unpredictability in quality as well as inaccessibility of many manuka stands. The feasibility of increasing production by establishing manuka plantations using plants known to produce nectar with high DHA content is being investigated. This study compared establishment, growth and nectar DHA content of four manuka provenances; two from Northland, and one each from Waikato and Wairarapa in a replicated, randomised complete block trial (Site A). In addition a manuka plantation of a single provenance was monitored for nectar DHA content (Site B). Both sites are in the Whanganui area. Survival of seedlings in the Site A trial at 12 months was high in all provenances. Nectar DHA content ranged from 3666 to 6902 mg/kg 80° Brix and there were no significant differences amongst the provenances. These DHA levels were considerably higher than levels measured in the local manuka (2565 mg/kg 80° Brix). At Site B nectar DHA content of the plantation manuka (5770 mg/kg 80° Brix) was significantly (P=0.05) higher than the indigenous manuka (2565 mg/kg 80° Brix). Early results suggest that manuka provenances can be utilised on different sites to produce high DHA nectar and ultimately high UMF manuka honey, providing landowners with an additional income and help prevent erosion of marginal hill country.fals

The effect of planting date on maize: Silage yield, starch content and leaf area

Four field experiments were established in the Waikato and Manawatu regions over two years to determine planting date (PD) influence on growth, silage yield (SY) and starch content of seven maize (Zea mays) hybrids. Silage yield response to PD was best described using quadratic regression models. The PD at which silage yield was maximised (optimum PD) was later in the cooler, high latitude environment of Manawatu (23 October) than the more northerly locations in Waikato (9-15 October). In both regions, planting 2 or 3 weeks either side of the optimum PD reduced SY by <5%. In Waikato, the optimum PD in a warmer than average spring (+1°C) was 1-2 weeks earlier. Under non-limiting moisture conditions later planting reduced yields in both Waikato (24.22 versus 21.06 t/ha) and Manawatu (30.09 versus 22.50 t/ha). This was attributed to decreased temperatures (<15°C) and radiation (<17 MJ/m2 /d) during grain filling. Due to more rapid reductions in autumn temperature and radiation in Manawatu, yield decline beyond the optimum PD was greater (-183 kg/ha/d (0.6%), R 2 =0.81) than Waikato (-50 to -85 kg/ha/d (0.3%), R 2 ≥0.67). Starch content was highest for plantings before 6 November, dropping thereafter with harvest index. Highest maximum leaf area index was observed at mean daily temperatures of 17-19°C.falsefalsefalsefalsefalsefalsefalsefals