Kodamaea kakaduensis and Candida tolerans, two new ascomycetous yeast species from Australian Hibiscus flowers.

Two new yeast species were isolated from flowers of Hibiscus species in Eastern and Northern Australia. Kodamaea kakaduensis is heterothallic, haploid, and similar to other Kodamaea species and to Candida restingae. Buds are often produced on short protuberances, and a true mycelium is formed. The new species differs from others by the assimilation of trehalose, melezitose, and xylitol, and is reproductively isolated. The cells of Candida tolerans are small and a pseudomycelium is formed. The carbon and nitrogen assimilation pattern is reminiscent of that of Zygosaccharomyces rouxii but the two are not closely related. Sequences of the D1/D2 domain of large subunit ribosomal DNA confirm the membership of K. kakaduensis in the genus Kodamaea and indicate that C. tolerans belongs to the Clavispora-Metschnikowia clade, with a moderate relatedness to Candida mogii. The type strains are: K. kakaduensis, UWO(PS)98-119.2 (h+, holotype, CBS 8611) and UWO(PS)98-117.1 (h-, isotype, CBS 8612); and C. tolerans, UWO(PS)98-115.5 (CBS 8613).     

The Global Environment Facility and biodiversity conservation: lessons to date and suggestions for future action

The last five years in particular have seen increasing attention paid to biodiversity. This culminated at the Earth Summit last June with the completion of Agenda 21 and a major international Convention on Biological Diversity, a document signed by some 165 nations. Concurrent with the Convention negotiations was the development of a global fund for biodiversity conservation and other environmental priorities, the Global Environment Facility (GEF). The GEF is the largest fund to data put forward by the international community to address biodiversity loss, but, so far, it has failed to set adequate priorities for biodiversity conservation. It has also yet to recognize the full range of biodiversity values and uses and, in general, GEF projects have not taken advantage of existing non-governmental capacity for biodiversity conservation. 1993 is a critical year for the GEF, one in which the GEF can become a critical element of global efforts to conserve biodiversity or remain an important initialive that realized only a fraction of its potential.     

Exercise training increases K+-channel contribution to regulation of coronary arterial tone

The present study examined whether regulation ofcoronary tone in conduit arteries (>1.0 mm ID) is altered by exercisetraining. Yucatan miniature swine were treadmill trained for 16-20wk (Ex) and compared with sedentary counterparts (Sed).Endothelium-denuded arterial rings were stretched to optimal length andallowed to equilibrate for 60 min. Inhibition of eitherCa²⁺-activated channels [1mM tetraethylammonium (TEA) or 10 nM iberiotoxin (IBTX)] orvoltage-dependent K⁺ channels[1 mM 4-aminopyridine (4-AP)] significantlyincreased resting tension in both groups; however, the effect of allK⁺-channel blockers was greater inEx. Addition of 1 mM sodium nitroprusside reduced resting tension inboth groups, confirming the presence of active basal tone; however,sodium nitroprusside-sensitive tone was increased approximately twofoldin Ex compared with Sed group. Perforated patch-clamp experiments onisolated smooth muscle cells demonstrated no effect of exercisetraining on whole cell TEA-sensitive, 4-AP-sensitive, or basalK⁺ current. Similarly, whereasTEA, 4-AP, and IBTX all decreased resting membrane potential, there wasno difference in depolarization between groups. The greater effect ofTEA on resting tension in Ex could be mimicked in Sed by addition ofthe Ca²⁺-channel agonist BAY K8644. In conclusion, the greater response toK⁺-channel blockers after exercisetraining is consistent with an increased contribution ofK⁺ channels to regulation of basaltone in conduit coronary arteries. The lack of an effect of training onK⁺ current characteristics ormembrane potential responses in isolated cells suggests that arequisite factor for enhancedK⁺-channel activation in arteriesfrom Ex, possibly stretch, is absent in isolated cells.

     

Roles of the mitogen-activated protein kinase family in macrophage responses to colony stimulating factor-1 addition and withdrawal.

Colony stimulating factor-1 (CSF-1) (or macrophage CSF) is involved in the survival, proliferation, differentiation, and activation of cells of the monocyte/macrophage lineage. Because the mitogen-activated protein kinase family members extracellular signal-regulated kinases (ERKs), p38, and c-Jun N-terminal kinase are widely implicated in such cellular functions, we measured their activity in growing and growth-arrested cultures of bone marrow-derived macrophages (BMM), as well as their stimulation by saturating concentrations of CSF-1. ERK activity was approximately 2-fold higher in cycling BMM compared with growth-arrested BMM; in addition, CSF-1-stimulated BMM DNA synthesis was partially inhibited by PD98059, a specific inhibitor of MEK activation, suggesting a role for a mitogen-activated protein-ERK kinase (MEK)/ERK pathway in the control of DNA synthesis but surprisingly not in the control of cyclin D1 mRNA or c-myc mRNA expression. The suppression of BMM apoptosis by CSF-1, i.e. enhanced survival, was not reversed by PD98059, suggesting that a MEK/ERK pathway is not involved in this process. Using a quantitative kinase assay, it was found that CSF-1 gave a slight increase in BMM p38 activity, supporting prior data that CSF-1 is a relatively weak stimulator of inflammatory cytokine production in monocytes/macrophages. Relatively high concentrations of the p38 inhibitor, SKB202190, suppressed CSF-1-stimulated BMM DNA synthesis. No evidence could be obtained for the involvement of p38 activity in BMM apoptosis following CSF-1 withdrawal. We were not able to show that CSF-1 enhanced BMM JNK-1 activity to a significant extent; again, no role could be found for JNK-1 activity in the BMM apoptosis occurring after CSF-1 removal.     

Mitochondrial metabolism is a key regulator of the fibro-inflammatory and adipogenic stromal subpopulations in white adipose tissue

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Endopeptidase activity in jackbeans and its effect on Concanavalin A

Endopeptidase activity in mature jackbeans has been characterised. One major activity is present, that of a neutral metallo-endopeptidase. Using specific inhibitors it can be shown that the Concanavalin A-associated fragments are not formed by proteolytic degradation of the intact subunit on hydration of the tissue. The intact subunit of the lectin is also resistant to the degradation by the endogenous endopeptidase activity during a prolonged incubation in vitro. These results suggest that the lectin fragments have been formed during seed maturation and no further limited proteolysis of Concanavalin A occurs during the early stages of germination.