Trypanosome non-specific IgM antibodies detected in serum of Trypanosoma congolense-infected cattle are polyreactive

Research Article published by Elsevier Science Volume 69, Issue 1, 1 July 1999Serum Ig from Trypanosoma congolense-infected cattle were affinity-purified using immobilised trypanosome or non-trypanosome antigens (ß-galactosidase, cytochrome C and ferritin). The bound and unbound IgG and IgM fractions were collected and tested in ELISA for reactivity to each antigen. The results indicated that the presence of reactivity to non-parasite antigens in serum of infected cattle is due to polyreactive IgM antibodies. However, the IgG fraction only bound to trypanosome antigens and was only present in post-infection sera, indicating that it was induced by the infecting trypanosomes. Since the polyreactive IgM antibodies were also present in pre-infection sera, it is probable that they were natural antibodies that were not induced but only amplified by the trypanosome infection

The water uptake of poly(tetrahydrofurfuryl methacrylate)

Research Article published by Elsevier Volume 20, Issue 5, March 1999Poly(tetrahydrofurfuryl methacrylate) possesses some unique characteristics with respect to its biocompatibility and behaviour in water. The water uptake is high (>70%) and very slow (over 3 yr), but the material remains rigid throughout the process. The mechanism behind the uptake is in two stages; an initial Fickian stage, then as the matrix approaches saturation (about 3 wt%) a second clustering mechanism takes over. The rate of uptake of the second stage of the uptake is controlled by creep (or stress relaxation), and the chemical potential driving the uptake from clustering of the furfuryl rings of the polymer. If clustering or the creep is prevented (by appropriate co-polymerisation) the polymer behaves in an ideal, Fickian manner

CD5+ B lymphocytes are the main source of antibodies reactive with non-parasite antigens in Trypanosoma congolense-infected cattle

Research Article published by Blackwell Science LtdMice infected with African trypanosomes produce exceptionally large amounts of serum IgM, a major part of which binds to non-trypanosome antigens such as trinitrophenol and single-strand DNA. In this paper, we describe that in cattle infected with Trypanosoma congolense and T. vivax, similar antibodies are found, although they bind mainly to protein antigens, such as b-galactosidase, ovalbumin and ferritin. The parasite non-specific IgM antibodies appear around the same time as the parasite-specific antibodies, but their origin and function are not clear.We tested the hypothesis that CD5+ B cells (or B-1 cells), which increase during trypanosome infections in cattle, are responsible for production of antibodies to non-trypanosome antigens. Splenic CD5+ and CD5− B cells from infected cattle were sorted and tested in a single cell blot assay. The numbers of immunoglobulin-secreting cells were similar in both B-cell populations. However, antibodies with reactivity for non-trypanosome antigens were significantly more prevalent in the CD5+ B-cell fraction and were exclusively IgM. The preference for production of these antibodies by CD5+ B cells and the expansion of this subpopulation during infections in cattle, strongly suggest that CD5+ B cells are the main source of trypanosome non-specific antibodies. We propose that these antibodies are natural, polyreactive antibodies that are predominantly secreted by CD5+ B cells. Since B-1 cells are up-regulated in many states of immune insufficiency, the immunosuppression associated with trypanosome infections may be responsible for the increase of this subset and the concomitant increase in trypanosome non-specific antibodies

Rise in erythropoietin concentrations in experimental Trypanosoma congolense infection of calves

Research Article published by Elsevier Ltd. Volume 113, Issue 4, November 1995A bioassay was used to measure erythropoietin (EPO) concentrations in calves with haemorrhagic anaemia due to blood loss and in calves with anaemia due to Trypanosoma congolense infection. The bioactivity of EPO was measured in the assay by its stimulatory effect on 125I-deoxyuridine incorporation in spleen cells from phenylhydrazine-treated mice. Erythropoietin concentrations in blood-volume-depleted calves were elevated 6h after blood loss, maximal (1225 mU/ml) at 33 h and below detection limits at 72 h. Reticulocytes (0·05±0·1%) appeared in blood by 72 h, peaked at 120 h and disappeared from the circulation by 7 days after bleeding. The packed cell volume (PCV) started increasing at 120 h and reached near prebleeding values by 14 days. In T. congolense-infected calves, parasites were first detected in the peripheral blood 12 days post-infection (dpi). Parasitaemia peaked (5×105 trypanosomes/ml of blood) at 15–18 dpi and, thereafter, several waves of parasitaemia were observed, but the peaks gradually diminished. Undiluted plasma from T. congolense-infected calves suppressed 125I-deoxyuridine incorporation into spleen cells from 13 dpi onwards. The suppressive effect of plasma was partly negated by five-fold dilution, which made possible the detection of increased EPO concentrations during the acute and chronic stages of the anaemia. The highest EPO peaks, reaching 2300 mU/ml in one calf, were detected during the chronic stage of the infection. At 15–39 dpi, there was a transient bone-marrow erythropoietic response characterized by an increase in mean corpuscular volume and a decrease in mean corpuscular haemoglobin concentration but with few reticulocytes (0·4%). However, from 76 dpi onwards, this response waned despite low PCV and elevated EPO concentrations. These results suggest that there is an ineffective erythroid response in the face of elevated EPO concentrations during bovine trypanosomiasis. The negative effect of plasma and serum from trypanosome-infected calves on the in-vitro bioactivity of EPO suggests the presence of inhibitory factors

Modifications of the hydrophilicity of heterocyclic methacrylate copolymers for protein release

Research Article published by Elsevier Volume 16, Issue 18, December 1995A series of copolymers comprising ethyl methacrylate (EM) and tetrahydrofurfuryl methacrylate (THFMA) gelled with either THFMA monomer or hydroxyethyl methacrylate (HEMA) monomer have been developed. In this paper, we examine the water uptake characteristics of the polymer systems and address the possibility of increasing the hydrophilicity of the systems by changing the ratios of the copolymers. We have investigated whether protein release from the polymers is related to the composition of the polymer systems. More protein was released from the polymers gelled with the more hydrophilic monomer (HEMA) than with THFMA. This was consistent with the calculated diffusion coefficients, which were 10 times greater for the polymers gelled with HEMA than those gelled with THFMA. Interestingly, the water uptake and protein release profiles were not dependent on the ratio of EM and THFMA in the copolymers. This is probably due to the conflicting roles of THFMA in the copolymer; it is both the more hydrophilic component as well as a cross-linking agent. In addition, it would appear that the structural and surface topography of these polymers had more significant effects on protein release than copolymer composition

Sensitivity analysis and uncertainty quantification of climate change effects on Tanzanian banana crop yield

This research article was published in the journal of Results in Control and Optimization, Volume 18, 2025Concerns about the impact of climate change on agricultural systems have heightened, par ticularly in regions where crop cultivation is essential for economic stability and sustenance. This research addresses a critical gap in understanding by investigating how climate change influences Tanzania’s bananas, a vital component of the country’s agricultural sector. The study used a multiple regression model to analyze the correlation between bananas and key climate variables in Tanzania, the results showed gradual decrease in bananas. Specifically, the climate variables, including precipitation (1), soil moisture (2), minimum temperature (3), maximum temperature (4), and relative humidity (5) have coefficients 0.0206, −0.0085, 4.8328, −1.6594, and −0.0991, respectively. In this case, a large positive coefficient and a negligible negative coefficient show that the independent variable greatly influences the yield of the bananas. Additionally, the study utilize two powerful global sensitivity analysis methods, Sobol’ Sensitivity Indices and Response Surface Methodology, to comprehensively explore the sensitivity of bananas to climate variables. So, these methods revealed that minimum temperature, precipitation and soil moisture have the most impact on bananas and affect the crop’s production variability. Uncertainty quantification was performed using Monte Carlo simulation, estimating uncertainties in model parameters to enhance the reliability of the findings. This research not only contributes to our broader understanding of how climate change impacts bananas but also offers practical policy suggestions tailored to Tanzania’s unique context, ensuring resilience and sustainability in the face of environmental changes. The outcomes of this study carry significance for policymakers, stakeholders, and farmers, providing actionable insights to shape adaptive agricultural strategies. By bridging the gap between climate change and banana

Drivers of increased soil erosion in East Africa’s agro-pastoral systems: changing interactions between the social, economic and natural domains

This research article was published by Springer Berlin Heidelberg in 2019Increased soil erosion is one of the main drivers of land degradation in East Africa’s agricultural and pastoral landscapes. This wicked problem is rooted in historic disruptions to co-adapted agro-pastoral systems. Introduction of agricultural growth policies by centralised governance resulted in temporal and spatial scale mismatches with the complex and dynamic East African environment, which subsequently contributed to soil exhaustion, declining fertility and increased soil erosion. Coercive policies of land use, privatisation, sedentarisation, exclusion and marginalisation led to a gradual erosion of the indigenous social and economic structures. Combined with the inability of the new nation-states to provide many of the services necessary for (re)developing the social and economic domains, many communities are lacking key components enabling sustainable adaptation to changing internal and external shocks and pressures. Exemplary is the absence of growth in agricultural productivity and livelihood options outside of agriculture, which prohibits the absorption of an increasing population and pushes communities towards overexploitation of natural resources. This further increases social and economic pressures on ecosystems, locking agro-pastoral systems in a downward spiral of degradation. For the development and implementation of sustainable land management plans to be sustainable, authorities need to take the complex drivers of increased soil erosion into consideration. Examples from sustainable intensification responses to the demands of population increase, demonstrate that the integrity of locally adapted systems needs to be protected, but not isolated, from external pressures. Communities have to increase productivity and diversify their economy by building upon, not abandoning, existing linkages between the social, economic and natural domains. Locally adapted management practices need to be integrated in regional, national and supra-national institutions. A nested political and economic framework, wherein local communities are able to access agricultural technologies and state services, is a key prerequisite towards regional development of sustainable agro-pastoral systems that safeguard soil health, food and livelihood security