Biogeographical survey of soil microbiomes across sub-Saharan Africa: structure, drivers, and predicted climate-driven changes.

BACKGROUND: Top-soil microbiomes make a vital contribution to the Earth's ecology and harbor an extraordinarily high biodiversity. They are also key players in many ecosystem services, particularly in arid regions of the globe such as the African continent. While several recent studies have documented patterns in global soil microbial ecology, these are largely biased towards widely studied regions and rely on models to interpolate the microbial diversity of other regions where there is low data coverage. This is the case for sub-Saharan Africa, where the number of regional microbial studies is very low in comparison to other continents. RESULTS: The aim of this study was to conduct an extensive biogeographical survey of sub-Saharan Africa's top-soil microbiomes, with a specific focus on investigating the environmental drivers of microbial ecology across the region. In this study, we sampled 810 sample sites across 9 sub-Saharan African countries and used taxonomic barcoding to profile the microbial ecology of these regions. Our results showed that the sub-Saharan nations included in the study harbor qualitatively distinguishable soil microbiomes. In addition, using soil chemistry and climatic data extracted from the same sites, we demonstrated that the top-soil microbiome is shaped by a broad range of environmental factors, most notably pH, precipitation, and temperature. Through the use of structural equation modeling, we also developed a model to predict how soil microbial biodiversity in sub-Saharan Africa might be affected by future climate change scenarios. This model predicted that the soil microbial biodiversity of countries such as Kenya will be negatively affected by increased temperatures and decreased precipitation, while the fungal biodiversity of Benin will benefit from the increase in annual precipitation. CONCLUSION: This study represents the most extensive biogeographical survey of sub-Saharan top-soil microbiomes to date. Importantly, this study has allowed us to identify countries in sub-Saharan Africa that might be particularly vulnerable to losses in soil microbial ecology and productivity due to climate change. Considering the reliance of many economies in the region on rain-fed agriculture, this study provides crucial information to support conservation efforts in the countries that will be most heavily impacted by climate change. Video Abstract.

The influence of surface soil physicochemistry on the edaphic bacterial communities in contrasting terrain types of the Central Namib Desert.

Notwithstanding, the severe environmental conditions, deserts harbour a high diversity of adapted micro-organisms. In such oligotrophic environments, soil physicochemical characteristics play an important role in shaping indigenous microbial communities. This study investigates the edaphic bacterial communities of three contrasting desert terrain types (gravel plains, sand dunes and ephemeral rivers) with different surface geologies in the Central Namib Desert. For each site, we evaluated surface soil physicochemistries and used explorative T-RFLP methodology to get an indication of bacterial community diversities. While grain size was an important parameter in separating the three terrain types physicochemically and specific surface soil types could be distinguished, the desert edaphic bacterial communities displayed a high level of local spatial heterogeneity. Ten variables contributed significantly (P < 0.05) to the variance in the T-RFLP data sets: fine silt, medium and fine sand content, pH, S, Na, Zn, Al, V and Fe concentrations, and 40% of the total variance could be explained by these constraining variables. The results suggest that local physicochemical conditions play a significant role in shaping the bacterial structures in the Central Namib Desert and stress the importance of recording a wide variety of environmental descriptors to comprehensively assess the role of edaphic parameters in shaping microbial communities.

Improving organ procurement travel practices in the United States: proceedings from the Michigan Donor Travel Forum.

There are significant risks and inefficiencies associated with organ procurement travel. In an effort to identify, quantify, and define opportunities to mitigate these risks and inefficiencies, 25 experts from the transplantation, transportation and insurance fields were convened. The forum concluded that: on procurement travel practices are inadequate, there is wide variation in the quality of aero-medical transportation, current travel practices for organ procurement are inefficient and there is a lack of standards for organ procurement travel liability coverage. The forum concluded that the transplant community should require that air-craft vendors adhere to industry quality standards compatible with the degree of risk in their mission profiles. Within this context, a purchasing collaborative within the transplant community may offer opportunities for improved service and safety with lower costs. In addition, changes in travel practices should be considered with broader sharing of procurement duties across centers. Finally, best practice standards should be instituted for life insurance for transplant personnel and liability insurance for providers. Overall, the aims of these proposals are to raise procurement travel standards and in doing so, to improve the transplantation as a whole.

Organ donation and utilization in the United States, 1996-2005.

The success of clinical transplantation as a therapy for end-stage organ failure is limited by the availability of suitable organs for transplant. This article discusses continued efforts by the transplant community to collaboratively improve the organ supply. There were 7593 deceased organ donors in 2005. This represents an all-time high and a 6% increase over 2004. Increases were noted in deceased organ donation of all types of organs; notable is the increase in lung donation, which occurred in 17% of all deceased donors. The percentage of deceased donations that occurred following cardiac death has also reached a new high at 7%. The number of living donors decreased by 2%, from 7003 in 2004 to 6895 in 2005. This article discusses the continued efforts of the Organ Donation Breakthrough Collaborative and the Organ Transplantation Breakthrough Collaborative to support organ recovery and use and to encourage the expectation that for every deceased donor, all organs will be placed and transplanted.

Connecting research to combating desertification.

With and without the encouragement of the United Nations Convention to Combat Desertification and its Committee on Science and Technology, scientific research has been undertaken throughout the drylands with the expectation of contributing to combating desertification. Little of this research has been applied in developing countries for its identified purpose. The main reason for this is the limited translation of scientific research into an accessible format for application by development agencies or rural communities.

Connecting community action and science to combat desertification: evaluation of a process.

Combating desertification requires the involvement of many people ranging from communities who experience the effects on a daily basis and scientists attempting to understand the biophysical and socio-economic causes and consequences of desertification, to developers and policy makers on all levels. In many instances, however, the understanding, approaches and actions of these different groups contradict rather than support one another. Over the period 2000 to 2002, a conference process undertaken in southern Africa brought together communities, scientists, and development workers to test the concept that they could connect and work together to combat desertification, given an appropriate framework. The conference was a success, and communities, scientists and developers did exchange experience, knowledge and information. Many lessons were learned, although some pitfalls were experienced. Time, funding, enhanced communication, and good will are the primary ingredients for ensuring that different sectors complement one another in their efforts to combat desertification.

Thirty-seven years of renal transplantation in Oregon.

What we accomplish today as a matter of routine was only imagined by a few 4 decades ago. The journey from that first successful kidney transplant in the 1950s to the multidisciplinary, multiorgan transplant program of today has been a fascinating one. Although we attribute our current results to careful recipient selection and preparation, improvements in organ procurement and preservation, refinement of surgical techniques, improvement in histocompatibility techniques and organ sharing, improvements in immunosuppression and infection control, and careful monitoring of recipients, we and our patients have benefited from significant contributions from our colleagues in government and the law. The 4 that come to mind are the provision of near-universal insurance coverage for end stage renal disease patients in 1972 under the Medicare program, the passage of brain death laws in the mid 1970s, the passage of the National Transplant Act in 1984, and the passage of the Oregon required request law in 1985.

Routine inquiry of organ and tissue donation: the Oregon experience.

This article introduces the critical care nurse to a successful statewide effort to promote organ and tissue donation. Because it was one of the first to implement routine inquiry, the state of Oregon's experience was watched closely by the nation. The need for, implementation, and effects of the first routine inquiry legislation in the United States are recounted and analyzed in this article.

Outcome of renal transplantation at Oregon Health Sciences University: 1982 to 1990.

1. Graft survival increased over the 4 periods between 1982 and 1990 (82-84, 85-86, 87-88, 89-90). The largest increase was in the 89-90 period. 2. Immunosuppression was the key to improved outcome. Cadaveric graft recipients given OKT3 induction plus triple therapy with cyclosporine, azathioprine, and prednisone had significantly better graft survival compared with all other drug combinations. Other factors were improved patient selection, donor management, and outpatient care. 3. Mean serum creatinine levels did not change after cyclosporine was introduced for immunosuppression. The mean serum creatinine level was approximately 1.7 mg/dl at 3 months, 6 months, and 12 months post-transplantation in all 4 periods. 4. Living-related donor outcome was significantly better than cadaveric donor outcome. Half-life for 2-haplotype-matched kidneys was 37 years compared with 12 years for 1-haplotype matches and 6.5 years for cadaveric kidneys. 5. Immediate function and a rejection-free first month were both associated with significantly improved graft survival. 6. Neither peak PRA nor graft number (1st vs regraft) correlated with graft survival. Highly sensitized (PRA greater than 50%) patients and regrafted patients fared as well as less sensitized (PRA less than or equal to 50%) and first graft recipients. This outcome was attributed to a sensitive crossmatch. Because of the crossmatch, highly sensitized patients received much better HLA matches. 7. The incidence of early rejection and delayed function declined significantly between the earliest and latest periods. Improved immunosuppression, donor management, and renal preservation were cited as contributing factors.

Lizard herbivory in a sand dune environment: the diet of Angolosaurus skoogi.

Early observations of the feeding habits of Angolosaurus skoogi (Andersson), a 50-120 g lizard inhabiting the almost vegetationless dunes of the northern Namib Desert, indicated that this species was herbivorous. Less than two percent of living lizard species are predominantly herbivorous and these species tend to have a high body mass (>100 g). We therefore analysed fecal pellets of A. skoogi to obtain dietary details of this relatively rare lizard. Eighteen food taxa were identified: 81 percent by mass was composed of vegetable matter, of which 56 percent was an endemic, perennial cucurbit Acanthosicyos horrida. Both spatial and temporal variation in dietary composition were apparent. Ready access to water in the form of A. horrida is postulated to have allowed Angolosaurus to occupy this extreme habitat and to forage on components of the windblown detritus, a food source that would probably not be usable in other circumstances.

Dynamics of the wax bloom of a seasonal Namib Desert tenebrionid, Cauricara phalangium (Coleoptera: Adesmiini).

The dynamics of the extracuticular was bloom in a 'winter' species of tenebrionid beetle, Cauricara phalangium, from the Namib Desert were monitored in the field and under laboratory conditions. The beetles possessed a full complement of the white wax material after adult emergence. The amount of this material on the integument declined towards the end of the season. The wax bloom was regenerated in both the field and laboratory, with high temperatures and low humidities bringing about greatest renewal. End of the season decline appears tobe related to the senescence of these seasonal beetles. Water loss rates differed significantly for individuals collected in May, when fully bloomed, and in August when little or no wax bloom was present. The wax bloom material contributes to the protection of these diurnal beetles against the high temperatures and radiant heat loads in the Namib Desert.

A safe and effective disposable low pressure suction drain.

The physical and microbiological properties of a new disposable suction drainage system have been investigated under clinical and laboratory conditions. The system appears to have overcome the disadvantages associated with previous disposable and reusable low pressure suction drainage systems for use after surgical operation in that this system effectively prevents reflex and retrograde contamination.

Irregular fog as a water source for desert dune beetles.

Three methods of fog-water uptake have been observed in three tribes of Namib desert dune tenebrionid beetles, Adesmiini, Eurychorini and Zophosini. The methods used correlate with distribution and gross morphology of each species but cut across phylogenetic affinities. Of the three methods described, none involve obvious fine anatomical or physical adaptations of the beetles for fog-water uptake. Rather, the beetles have evolved specific behavioural patterns for drinking water condensed on vegetation, their own dorsum or sand.Use of fog-water necessitates surface activity at times when surface temperatures and wind velocities are not optimal for these diurnal or crepuscular species. Behavioural adaptation has enabled these beetles to use irregular and unpredictable fogs as a moisture source.

Fog catchment sand trenches constructed by tenebrionid beetles, lepidochora, from the namib desert.

Three species of coastal Namib Desert tenebrionid beetles (Lepidochora) build trenches on desert sand dunes. Trenches are constructed perpendicular to fog winds and concentrate moisture during fogs. The beetles return along the ridges of the trenches extracting water from them. The water content of a population of these beetles increased by 13.9 percent during one fog.