Ground wētā in vines of the Awatere Valley,Marlborough: biology,density and distribution

The endemic New Zealand ground wētā (Hemiandrus sp. ‘promontorius’) has a Naturally Uncommon conservation status. This is because of the paucity of information on its density and distribution. Here, the biology, density and distribution of a population of this wētā found in and around vineyards in the Awatere Valley, Marlborough was studied. Wētā density was assessed in vineyards, paddocks and shrublands in this valley. Soil moisture, penetration resistance, pH and organic matter were recorded at locations with and without wētā. Wētā density in vineyards was significantly higher than in either paddocks or shrub habitats. In vineyards, the density of this insect was significantly higher under-vines than in the inter-rows. Higher numbers of this wētā were found in moist soils that required lower force to burrow. Females laid an average of 55 eggs between March and April, which hatched in September. These findings highlight the intersection between agriculture and conservation.     

Treatment with a sphingosine analog after the inception of house dust mite-induced airway inflammation alleviates key features of experimental asthma

Background

In vivo phosphorylation of sphingosine analogs with their ensuing binding and activation of their cell-surface sphingosine-1-phosphate receptors is regarded as the main immunomodulatory mechanism of this new class of drugs. Prophylactic treatment with sphingosine analogs interferes with experimental asthma by impeding the migration of dendritic cells to draining lymph nodes. However, whether these drugs can also alleviate allergic airway inflammation after its onset remains to be determined. Herein, we investigated to which extent and by which mechanisms the sphingosine analog AAL-R interferes with key features of asthma in a murine model during ongoing allergic inflammation induced by Dermatophagoides pteronyssinus.

Methods

BALB/c mice were exposed to either D. pteronyssinus or saline, intranasally, once-daily for 10 consecutive days. Mice were treated intratracheally with either AAL-R, its pre-phosphorylated form AFD-R, or the vehicle before every allergen challenge over the last four days, i.e. after the onset of allergic airway inflammation. On day 11, airway responsiveness to methacholine was measured; inflammatory cells and cytokines were quantified in the airways; and the numbers and/or viability of T cells, B cells and dendritic cells were assessed in the lungs and draining lymph nodes.

Results

AAL-R decreased airway hyperresponsiveness induced by D. pteronyssinus by nearly 70%. This was associated with a strong reduction of IL-5 and IL-13 levels in the airways and with a decreased eosinophilic response. Notably, the lung CD4⁺ T cells were almost entirely eliminated by AAL-R, which concurred with enhanced apoptosis/necrosis in that cell population. This inhibition occurred in the absence of dendritic cell number modulation in draining lymph nodes. On the other hand, the pre-phosphorylated form AFD-R, which preferentially acts on cell-surface sphingosine-1-phosphate receptors, was relatively impotent at enhancing cell death, which led to a less efficient control of T cell and eosinophil responses in the lungs.

Conclusion

Airway delivery of the non-phosphorylated sphingosine analog, but not its pre-phosphorylated counterpart, is highly efficient at controlling the local T cell response after the onset of allergic airway inflammation. The mechanism appears to involve local induction of lymphocyte apoptosis/necrosis, while mildly affecting dendritic cell and T cell accumulation in draining lymph nodes.     

The abundance of an invasive freshwater snail Tarebia granifera (Lamarck, 1822) in the Nseleni River,South Africa

The invasive freshwater snail Tarebia granifera (Lamarck, 1822) was first reported in South Africa in 1999 and it has become widespread across the country, with some evidence to suggest that it reduces benthic macroinvertebrate biodiversity. The current study aimed to identify the primary abiotic drivers behind abundance patterns of T. granifera, by comparing the current abundance of the snail in three different regions, and at three depths, of the highly modified Nseleni River in KwaZulu-Natal, South Africa. Tarebia granifera was well established throughout the Nseleni River system, with an overall preference for shallow waters and seasonal temporal patterns of abundance. Although it is uncertain what the ecological impacts of the snail in this system are, its high abundances suggest that it should be controlled where possible and prevented from invading other systems in the region.     

Studies of cereal nematode populations and cereal yields under continuous or intensive culture

In a field experiment on infested sandland from 1955 to 1967, numbers of Heterodera avenae increased only in 1957 and then decreased under both continuous and rotational spring oats (1955-62) and subsequently under spring barley (1963-67). Fluctuations in numbers of Pratylenchus neglectus and Trichodorus primitivus were recorded from 1963 to 1967. Cereal grain yields were generally unsatisfactory, but were consistently higher for cereals grown in rotation rather than continuously. Extra nitrogen fertilizer gave slightly improved yields with higher post-cropping numbers of H. avenae.     

Response of mitochondria to light intensity in the leaves of sun and shade species

The present authors have shown previously that both respiration rates and in vivo activities of the alternative oxidase (AOX) of leaves of Alocasia odora, a shade species, are lower than those in sun species, thereby optimizing energy production under limited light conditions (Noguchi et al., Australian Journal of Plant Physiology 28, 27–35, 2001). In the present study, mitochondria isolated from A. odora leaves were examined in order to investigate the biochemical basis for the differences in respiratory parameters. Alocasia odora and spinach plants were cultivated under both high and low light intensities, mitochondria were isolated from their leaves, and their respiratory properties compared. Mitochondrial content of leaf extracts from the two species was estimated using fumarase activities and antibody detection of porin (the voltage-dependent anion channel of the outer mitochondrial membrane). On a mitochondrial protein basis, spinach leaves showed higher capacities of the cytochrome pathway and cytochrome c oxidase (COX) than A. odora leaves. However, on a mitochondrial protein basis, A. odora showed higher capacities of AOX, which had a high affinity for ubiquinone when activated by pyruvate. Alocasia odora also had larger amounts of mitochondrial protein per leaf dry weight, even under severely shaded conditions, than spinach. Lower growth light intensity led to lower activities of most pathways and proteins tested in both species, especially glycine-dependent oxygen uptake. In the low light environment, most of the AOX protein in A. odora leaves was in its inactive, oxidized dimer form, but was converted to its reduced active form when plants were grown under high light. This shift may prevent over-reduction of the respiratory chain under photo-oxidative conditions.     

An Ustilago maydis Mutant Partially Blocked in P45014DM Activity Is Hypersensitive to Azole Fungicides

An Ustilago maydis ergosterol biosynthesis mutant (A14) which is partially blocked in sterol 14alpha-demethylase (P45014DM) activity is described. This mutant accumulated the abnormal 14alpha-methyl sterols, eburicol, 14alpha-methylfecosterol, and obtusifoliol, along with significant amounts of ergosterol. Although the A14 mutant grew nearly as well as the wild type, it was impaired in cell extension growth, which indicated a dysfunction in apical cell wall synthesis. The mutant was also found to be hypersensitive to the azole fungicides penconazole and tebuconazole.