Aliens in the nursery: assessing the attitudes of nursery managers to invasive species regulations

The horticultural industry is recognised as a major pathway for the introduction and spread of invasive alien plants (IAPs). The Conservation of Agricultural Resources Act (CARA) of 1983 (Act No. 43 of 1983) listed and categorised invasive species with an aim to curb their spread. The more recently enacted Alien and Invasive Species Regulations under South Africa’s National Environmental Management: Biodiversity Act (NEMBA) are intended, in part, to improve controls on the horticultural industry’s role in the spread of IAPs. In order to assess, and enhance, the likely effectiveness of NEMBA, it is important to build an understanding of stakeholders’ awareness and attitudes towards the control of IAPs and associated regulatory policies. A two-pronged approach—involving nursery manager interviews (n = 30) and plant stock audit assessments (n = 41)—was used to gauge the awareness, compliance and attitudes of nursery managers towards both the CARA and NEMBA invasive species regulations. Less than ten percent of audited nurseries were fully compliant with the NEMBA regulations, and over 50% were stocking IAPs that have been regulated for at least 13 years under CARA. This is despite high levels of awareness (70%) about the CARA regulations reported in the interviews. The majority (73.5%) of IAP species stocked in nurseries were NEMBA category 1b invaders such as Nerium oleander and Canna indica. These are widespread and well-established invaders that require compulsory control under NEMBA. Half of the managers were not aware that the NEMBA regulations had been promulgated, but most respondents nevertheless reported being enthusiastic about compliance. Several factors were quoted as constraints on compliance by the industry. These included a perceived lack of enforcement, weak communication from government, and the lack of inclusion of the industry in the regulatory process. Suggested interventions that could enhance the impact of IAP regulations will involve improving the user-friendliness of the regulations, and supplementing the current top-down approach to regulation with an inclusive partner-centred approach.     

Alien plants as mediators of ecosystem services and disservices in urban systems: a global review

Urban areas have unique assemblages of species which are governed by novel ecological processes. People living in these environments have specific needs and demands in terms of ecosystem services (ES). Urban ecosystems are transformed in many ways by human activities and their floras comprise a high proportion of alien plant species, many of which were intentionally introduced to provide, augment or restore ES. Urban environments also have novel disturbance regimes and provide colonization sites for the establishment, dispersal and proliferation of alien plant species; such conditions often generate biological invasions which may cause marked changes to ES. We review the roles that alien plants play in providing urban ES and ecosystem disservices (EDS) globally. We identify the main ES and EDS associated with alien plants, and highlight the key species involved. A literature search revealed 335 papers, representing studies in 58 cities or urban areas in 27 countries. These studies recorded 337 alien plant species, contributing to 39 different ES and 27 EDS–310 species were recorded as contributing to ES and 53 species to EDS. A small number of alien plant taxa were frequently recorded as providing multiple ES in many urban ecosystems; the 10 most recorded species accounted for 21% of the ES recorded. Some of these species also result in significant EDS; three species accounted for 30% of the EDS recorded. Cultural services (notably aesthetics) are the most reported ES provided by alien plants in urban areas of developed countries, while provisioning services (notably food production) are most reported in developing countries. The most commonly studied EDS provided by alien plants is the impact on human health (notably allergic reactions). Eighty percent of studies on alien plants and ES and EDS have been done in developed countries. To elucidate the full range of effects of alien plants, more work is needed in developing countries. Urban planners and managers need to be mindful of both the positive and negative impacts of alien plant species to maximise the provision of ES.     

Beschreibung dreier neuer Phlyctochytrien und eines Rhizophidium (Chytridiales) aus Erdboden

Zusammenfassung Beschreibung der 4 neuen Chytridineen Phlyctochytrium kniepii, Phl. africanum, Phl. palustre und Rhizophidium racemosum.Teilergebnis der Dissertation von A. Gaertner Über das Vorkommen einiger niederer Phycomyceten in Bodenproben aus Afrika, Deutschland und Schweden der mathemat.-naturwissensch. Fakultät in Göttingen.     

Beobachtungen über die Bewegungsweise von Chytridineenzoosporen

Zusammenfassung Die Zoosporen von 4 Vertretern der GattungPhlyctochytrium (Phlyctochytrium n. sp.Sv 43, Phlyctochytrium n. sp.Alg. 3, Phlyctochytrium B 45 I undPhlyctochytrium n. sp. Reinboldt) sind in der Lage, sich auf Agar und mit Ausnahme vonPhlyctochytrium n. sp. Reinboldt, das auf diesem Substrat nicht wächst, auch im Carrageen-Schleim und in Gummi arabicum-Lösung mit vorn inserierter Geißel zu bewegen, wobei dieselbe dicht am Körper der Zoospore umbiegt, nach hinten gerichtet bleibt und meist weiterhin als Schubgeißel fungiert. Dies tritt auch im Wassertropfen auf, wenn er, nicht vom Deckglas bedeckt, eine sehr dünne Schicht auf dem Objektträger bildet. Die Geißel kann sich versteifen und beliebig herumgeworfen werden.Teilergebnis der Dissertation der mathematisch-naturwissenschaftlichen Fakultät der Universität GöttingenAlwin Gaertner, Über das Vorkommen einiger niederer Phycomyceten in Bodenproben von Afrika, Deutschland und Schweden.     

Association of the abundance and vertical distribution of tuna and beakfish in the southeast of the Caribbean sea

The longline hooks suspension depth was estimated using the Mechanic Imitation of Flexible Systems method. The vertical distribution of tunas and billfish was determined by the relative abundance index, obtained from the catch by 11 to 25 m -long longline vessels, -based at Cumaná, Venezuela, South-eastern Caribbean Sea in depths of 65 to 142 m. The CPUE was evaluated per species, according to depth. High values were found for most of the captured species in the layer from 105 to 125 m. Yellowfin tuna (Thunnus albacares) showed the highest yield (3.37 fish/100 hooks) and blue marlin (Makaira nigricans) the lowest (0.04 fish/100 hooks). However, the statistical comparison did not allow to reject the hypothesis of lack of depth efect (Kruskal-Wallis p > .05), and demonstrated a homogeneous distribution of yellowfin tuna (Thunnus albacares), albacore (Thunnus alalunga), bigeye tuna (Thunnus obesus), sailfish (Istiophorus albicans), white marlin (Tetrapturus albidus) and blue marlin (Makaira nigricans) in the water column. The conclusion is that fish concentration in the Southern border of the Caribbean Sea is possibly due to several hydroclimatic factors--which affect tuna and billfish catching--such as water temperature and dissolved oxygen concentration which limit the distribution according to depth.     

Scar and pulmonary expression and shedding of ACE in rat myocardial infarction

We examined the topology of angiotensin-converting enzyme (ACE) mRNA expression, activity, and shedding in myocardial infarction-induced heart failure and sought to elucidate the source of the increased plasma ACE activity in this model. Three months after coronary ligature, lung, scar, and remaining viable left ventricular tissues were analyzed for ACE mRNA expression as well as tissue and solubilized ACE activity. ACE mRNA expression increased in the scar with respect to infarct severity, decreased in the lung, and remained unchanged in the left ventricle. ACE activity decreased in the lung and increased in the scar tissue and plasma. Shedding of ACE remained constant in the lung and increased in the scar. This study shows that ACE expression and activity is shifted from the pulmonary endothelium to the infarct scar tissue and that constancy of shedding in the lung and its increase in the scar are the source of the increased plasma ACE in congestive heart failure.     

Human immunodeficiency virus type 1 entry inhibitors selected on living cells from a library of phage chemokines

The chemokine receptors CCR5 and CXCR4 are promising non-virus-encoded targets for human immunodeficiency virus (HIV) therapy. We describe a selection procedure to isolate mutant forms of RANTES (CCL5) with antiviral activity considerably in excess of that of the native chemokine. The phage-displayed library of randomly mutated and N-terminally extended variants was screened by using live CCR5-expressing cells, and two of the selected mutants, P1 and P2, were further characterized. Both were significantly more potent HIV inhibitors than RANTES, with P2 being the most active (50% inhibitory concentration of 600 pM in a viral coat-mediated cell fusion assay, complete protection of target cells against primary HIV type 1 strains at a concentration of 10 nM). P2 resembles AOP-RANTES in that it is a superagonist of CCR5 and potently induces receptor sequestration. P1, while less potent than P2, has the advantage of significantly reduced signaling activity via CCR5 (30% of that of RANTES). Additionally, both P1 and P2 exhibit not only significantly increased affinity for CCR5 but also enhanced receptor selectivity, retaining only trace levels of signaling activity via CCR1 and CCR3. The phage chemokine approach that was successfully applied here could be adapted to other chemokine-chemokine receptor systems and used to further improve the first-generation mutants reported in this paper.     

Calpain-mediated mGluR1alpha truncation: a key step in excitotoxicity

Excitotoxicity mediated by glutamate receptors plays crucial roles in ischemia and other neurodegenerative diseases. Whereas overactivation of ionotropic glutamate receptors is neurotoxic, the role of metabotropic glutamate receptors (mGluRs), and especially mGluR1, remains equivocal. Here we report that activation of NMDA receptors results in calpain-mediated truncation of the C-terminal domain of mGluR1alpha at Ser(936). The truncated mGluR1alpha maintains its ability to increase cytosolic calcium while it no longer activates the neuroprotective PI(3)K-Akt signaling pathways. Full-length and truncated forms of mGluR1alpha play distinct roles in excitotoxic neuronal degeneration in cultured neurons. A fusion peptide derived from the calpain cleavage site of mGluR1alpha efficiently blocks NMDA-induced truncation of mGluR1alpha in primary neuronal cultures and exhibits neuroprotection against excitotoxicity both in vitro and in vivo. These findings shed light on the relationship between NMDA and mGluR1alpha and indicate the existence of a positive feedback regulation in excitotoxicity involving calpain and mGluR1alpha.     

Specific cell adhesion as potential cause of interactions between hybridoma cells and reactor surfaces

Hybridoma cells grown in the presence of different reactor surfaces were affected by the reactor surface properties. Cell growth rate and cell attachment were affected differently. To explain this observed effect a mechanism involving specific adhesion (mediated by fibronectin) of the cells to the reactor surfaces was proposed and tested.