Epidemiology of lobomycosis-like disease in bottlenose dolphins Tursiops spp. from South America and southern Africa

We report on the epidemiology of lobomycosis-like disease (LLD), a cutaneous disorder evoking lobomycosis, in 658 common bottlenose dolphins Tursiops truncatus from South America and 94 Indo-Pacific bottlenose dolphins T. aduncus from southern Africa. Photographs and stranding records of 387 inshore residents, 60 inshore non-residents and 305 specimens of undetermined origin (inshore and offshore) were examined for the presence of LLD lesions from 2004 to 2015. Seventeen residents, 3 non-residents and 1 inshore dolphin of unknown residence status were positive. LLD lesions appeared as single or multiple, light grey to whitish nodules and plaques that may ulcerate and increase in size over time. Among resident dolphins, prevalence varied significantly among 4 communities, being low in Posorja (2.35%, n = 85), Ecuador, and high in Salinas, Ecuador (16.7%, n = 18), and Laguna, Brazil (14.3%, n = 42). LLD prevalence increased in 36 T. truncatus from Laguna from 5.6% in 2007−2009 to 13.9% in 2013−2014, albeit not significantly. The disease has persisted for years in dolphins from Mayotte, Laguna, Salinas, the Sanquianga National Park and Bahía Málaga (Colombia) but vanished from the Tramandaí Estuary and the Mampituba River (Brazil). The geographical range of LLD has expanded in Brazil, South Africa and Ecuador, in areas that have been regularly surveyed for 10 to 35 yr. Two of the 21 LLD-affected dolphins were found dead with extensive lesions in southern Brazil, and 2 others disappeared, and presumably died, in Ecuador. These observations stress the need for targeted epidemiological, histological and molecular studies of LLD in dolphins, especially in the Southern Hemisphere.The Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) to E.R.S. (PQ 307846/2014-8) and P.H.O. (Process 572180/2008-0), and L.F. was sponsored by Petrobras through Petrobras Socio Ambiental.http://www.int-res.com/journals/dao/dao-home/2020-11-30am201

Levosimendan: a cardiovascular drug to prevent liver ischemia-reperfusion injury?

INTRODUCTION: Temporary occlusion of the hepatoduodenal ligament leads to an ischemic-reperfusion (IR) injury in the liver. Levosimendan is a new positive inotropic drug, which induces preconditioning-like adaptive mechanisms due to opening of mitochondrial KATP channels. The aim of this study was to examine possible protective effects of levosimendan in a rat model of hepatic IR injury. MATERIAL AND METHODS: Levosimendan was administered to male Wistar rats 1 hour (early pretreatment) or 24 hours (late pretreatment) before induction of 60-minute segmental liver ischemia. Microcirculation of the liver was monitored by laser Doppler flowmeter. After 24 hours of reperfusion, liver and blood samples were taken for histology, immuno- and enzyme-histochemistry (TUNEL; PARP; NADH-TR) as well as for laboratory tests. Furthermore, liver antioxidant status was assessed and HSP72 expression was measured. RESULTS: In both groups pretreated with levosimendan, significantly better hepatic microcirculation was observed compared to respective IR control groups. Similarly, histological damage was also reduced after levosimendan administration. This observation was supported by significantly lower activities of serum ALT (pearly = 0.02; plate = 0.005), AST (pearly = 0.02; plate = 0.004) and less DNA damage by TUNEL test (pearly = 0.05; plate = 0.034) and PAR positivity (pearly = 0.02; plate = 0.04). Levosimendan pretreatment resulted in significant improvement of liver redox homeostasis. Further, significantly better mitochondrial function was detected in animals receiving late pretreatment. Finally, HSP72 expression was increased by IR injury, but it was not affected by levosimendan pretreatment. CONCLUSION: Levosimendan pretreatment can be hepatoprotective and it could be useful before extensive liver resection

Coaching as a social process

In this conceptual paper, we argue the importance to the coaching profession of a critical understanding of coaching as a social process, in order to promote coaching as an enabler for change, and facilitate its use in other cultures and challenging contexts. We start with a critical analysis of the origin of coaching, arguing that neoliberal values have been embedded in the discourse of coaching. We also discuss the impact of coaching as an instrumental and ideological device, sometimes used in organisations as a process of control, and suggest that understanding coaching as a social process has the potential to transform it into an enabler for change. We propose a framework for understanding how different philosophical positions affect the way coaches may respond to the challenges of intercultural or oppressive social contexts. We conclude with a discussion of the implications for coaching research and development

Determinants of woody encroachment and cover in African savannas

Savanna ecosystems are an integral part of the African landscape and sustain the livelihoods of millions of people. Woody encroachment in savannas is a widespread phenomenon but its causes are widely debated. We review the extensive literature on woody encroachment to help improve understanding of the possible causes and to highlight where and how future scientific efforts to fully understand these causes should be focused. Rainfall is the most important determinant of maximum woody cover across Africa, but fire and herbivory interact to reduce woody cover below the maximum at many locations. We postulate that woody encroachment is most likely driven by CO2 enrichment and propose a two-system conceptual framework, whereby mechanisms of woody encroachment differ depending on whether the savanna is a wet or dry system. In dry savannas, the increased water-use efficiency in plants relaxes precipitation-driven constraints and increases woody growth. In wet savannas, the increase of carbon allocation to tree roots results in faster recovery rates after disturbance and a greater likelihood of reaching sexual maturity. Our proposed framework can be tested using a mixture of experimental and earth observational techniques. At a local level, changes in precipitation, burning regimes or herbivory could be driving woody encroachment, but are unlikely to be the explanation of this continent-wide phenomenon

Bush encroachment with specific reference to Acacia karoo encroachment

Acacia karoo encroachment is a serious ecological problem in certain veld types in South Africa. The growth and habitat requirements of A. karoo have not previously been studied in detail. This paper refers to an autecological study of the A. karoo seedling. Growth analyses indicate that the seedling is characterized by a low growth rate, that it is very sensitive to temperature changes and that light intensity is a less important ecological factor. The seedling is very sensitive to desiccation and it is suggested that under field conditions, favourable moisture conditions extending over a lengthy period together with high temperatures are the most important requirements for establishment. The possibility of a temperature boundary limiting the establishment of A. karoo is discussed and it is demonstrated that the average temperature climate of areas subject to A. karoo encroachment is very close to such a boundary. A. karoo encroachment can possibly be due to a temperature shift or to reduced grass competition.Keywords: plants|temperatures|light intensities|ecological factors|desiccation|competition|bushes|seedlings|Southern Africa|analyses|autecological field studies|habitat requirements|growth|veld types|ecological problems|bush encroachments|temperature effect

The goat in a bush-grass community

An investigation was conducted to determine whether goats could control bush regrowth and reinfestation after initial bush clearing. A dense stand of A. karoo was chopped and the regrowth subsequently grazed either rotationally or continuously by sheep or goats. Regular observations of grazing were undertaken and the effect of treatment on bush regrowth and on the grass component was evaluated.Keywords: goats|bushes|grasses|communities|bush control|regrowth vegetation|infestations|grazing|browsing|sheep|treatments|grass compositions|feeding|competition|continuous grazing systems|trees|mortalities|grass cover|Eastern Cape Province|rotational grazing systems|species list

A preliminary report on the effect of Acacia karoo competition on the composition and yield of sweet grassveld

In a large-scale experiment a dense stand of A. karoo was effectively killed by a basal bark application of 2,4,5-T at a concentration of 1.5 per cent acid equivalent in paraffin. There was no correlation between density of Acacia and either composition or basal cover of the grass component. After three years there was still no significant difference in the grass cover and composition of paddocks on which A. karoo had been cleared, and uncleared ungrazed control paddocks. There was no evidence that where grazing was precluded a dense stand of A. karoo would develop and retard improvement in botanical composition. Despite the similarity in cover and composition, uncleared paddocks yielded significantly less grass than cleared paddocks, both in dry and in wet seasons. Total costs of bush clearing averaged R6.80 per morgen.Keywords: Cathcart|Eastern Cape Province|tree densities|basal covers|grass compositions|clearings|ungrazed habitats|bush control|bark|botanical compositions|competition|experiments|grasses|veld|grasslands|sweetveld|yields|compositional analyses|acid|bush densitie

Discussion Forum:Development of semi-arid bushveld to its full potential. 2. Eastern Cape

Keywords: semi arid bushveld|bushveld|veld|development|Eastern Cape Province|potential

Effect of continuous grazing in the Dohne Sourveld on species composition and basal cover.

In a grazing trial conducted at the Dohne Agricultural Research Station, natural grassland was grazed continuously for 36 years with cattle. In a second investigation conducted on similar grassland, paddocks were grazed or rested, in all combinations of the four seasons of the year, over a ten year period. Changes in botanical composition and cover of the sward were monitored at regular intervals. The results of these investigations indicate that under a regime of non-selective grazing the composition of Dohne Sourveld is remarkably stable. After 36 years of continuous grazing the species composition of the sward was largely maintained. Floristically Dohne Sourveld is dominated by a small number of grass species of which Andropogon appendiculatus, Elionurus muticus, Heteropogon contortus, Sporobolus africanus, Themeda triandra and Tristachya leucothrix are the most important. These species react differently to under-utilisation or increasingly severe defoliation, enabling them to be classified into decreaser or increaser categories. Severe defoliation resulted in a marked decrease in basal cover but only small changes in relative species composition. As the intensity of defoliation increases, decrease in grass cover is associated with an increase of forbs, such as Senecio retrorsus.Keywords: andropogon appendiculatus; basal cover; botanical composition; continuous grazing; defoliation; disturbance history; dohne sourveld; elionurus muticus; grass cover; grasses; grassland; grazing; heteropogon contortus; non-selective grazing; plant succession; senecio retrorsus; species composition; sporobolus africanus; themeda triandra; tristachya leucothrix; veld conditionJournal of the Grassland Society of Southern Africa