Lactate dehydrogenase isozymes and allozymes of the nine-spined stickleback Pungitius pungitius (L.) (Osteichthyes: Gasterosteidae)

Zymograms indicate the existence of three loci coding for lactate dehydrogenase in the nine-spined stickleback Pungitius pungitius. The skeletal muscle locus is polymorphic for two codominant alleles: Ldh-A(100). and Ldh-A(140). Differences in allele frequencies among nine samples, obtained from eight geographically isolated populations, proved not significant in 28/36 pairwise comparisons. The frequency of Ldh-A(100) varied from 0.426 to 0.715. Significant differences in apparent Km (pyruvate) values were found among the LDH-A allozymes suggesting a functional basis for the selective maintenance of this polymorphism.     

Development of a decellularised dermis

The purpose of this investigation was to develop a decellularised human dermis suitable for allografting. Samples of human skin were obtained from deceased donors and taken through a series of steps to remove all cellular material. The steps were: chemical removal of the epidermis, disinfection, lysing of cells in hypotonic buffer, a detergent treatment and a nuclease buffer to remove residual nuclear material. Histological preparations of the decellularised dermis produced were then investigated. In addition residual DNA content, structural strength, collagen denaturation, cytotoxicity and in vivo tissue reactivity following implantation in a murine model were examined. For all donors tested there was no change in morphology as viewed by light microscopy. Mean DNA removal was evaluated at 92.1 %. There were no significant changes in structural strength or evidence of collagen degradation. The tissue did not appear to be cytotoxic or elicit an immune response when implanted in the mouse model. A decellularised tissue has been developed that would appear to be suitable for a range of surgical procedures.     

Accumulation of Biomass and Compositional Change Over the Growth Season for Six Photoperiod Sorghum Lines

Biomass sorghums [Sorghum bicolor (L.) Moench] are short-day photoperiod sensitive (PS) types, meaning that the crop will grow vegetatively late into the fall season in subtropical and temperate environments. This feature results in high biomass yield potential and mitigates drought susceptibility. The objective of this study is to assess biomass growth patterns and associated changes in composition over a growing season for PS sorghum. The experiment had a split-plot design with two replications, six PS sorghum genotypes, and 13 harvest dates. Harvest started at 60 days after planting (DAP) and continued every 15 days thereafter in both College Station (CS) and Corpus Christi (CC) in Texas, 2010. At each harvest, dry biomass yield, plant height and biomass composition (percent lignin and cellulose) were measured. For all genotypes, biomass accumulation followed a standard growth pattern which included an early lag phase, followed by a log phase of growth and finally, a general reduction in the rate of accumulation. The early lag phase ended at approximately 70 DAP, the log phase of growth ended at approximately 125 DAP, and biomass yields maximized between 180 and 225 DAP. The highest yielding genotype produced 24 Mg ha^?1. Plant heights up to 400 cm were also measured between 180 and 225 DAP. Plant height and biomass yield patterns were similar, indicating that height is important to increase yield. Lignin and cellulose concentrations increased with time; at the highest yields (between 180 and 225 DAP), maximum lignin content were 14.5 to 15.5 % and maximum cellulose content was 31 to 32 %. As with yield potential, significant differences were detected for composition as well. The growth curves indicate that PS biomass sorghum yields sufficiently and can be harvested as early as 130 DAP with maximum sorghum biomass accumulation occurring between 180 and 225 days. Thus, with careful selection and deployment of biomass sorghum hybrids, the harvest season of biomass sorghum can be extended over a 3-month period in southern regions of the US     

Hydrodynamic shearing of biological cells

An understanding of hydrodynamic shearing of biological cells provides basic information about the mechanical properties of cells, their deformations occurring in natural circulations and is necessary for effective design of artificial circulation devices. Several situations including (i) shearing in cone-plate viscometers, (ii) forced flow through tubes and hypodermic needles, as well as (iii) acoustic microstreaming near oscillating bubbles and wires provide controlled shearing. Details of the deformation and disruptions of cells in shear fields are understood by considerations of theory describing emulsification processes. Viscoelastic parameters of the erythrocyte can be obtained using a model based upon the dynamic behavior of polysulfide rubber.     

Plastic casts of embryonic respiratory and cardiovascular system: a technique.

This report describes a technique for producing plastic casts of the cardiovascular and respiratory systems of the chick embryo at Stage 36 or older. For casts of the cardiovascular system, polymerization compound is injected in the right ventricle filling the heart, venous, and arterial system. A two stage injection produced more detailed casts of the pulmonary vasculature. For respiratory system casts, the compound is injected in the trachea filling the bronchi and air sacs. Casts are prepared by tissue corrosion in 10% potassium hydroxide. This technique is an alternative to serial section reconstruction in the study of developing cardiovascular and respiratory system.     

Expression of Trypanosoma brucei gambiense Antigens in Leishmania tarentolae. Potential for Use in Rapid Serodiagnostic Tests (RDTs)

The development of rapid serodiagnostic tests for sleeping sickness and other diseases caused by kinetoplastids relies on the affordable production of parasite-specific recombinant antigens. Here, we describe the production of recombinant antigens from Trypanosoma brucei gambiense (T.b. gambiense) in the related species Leishmania tarentolae (L. tarentolae), and compare their diagnostic sensitivity and specificity to native antigens currently used in diagnostic kits against a panel of human sera. A number of T.b. gambiense protein antigen candidates were chosen for recombinant expression in L. tarentolae based on current diagnostics in field use and recent findings on immunodiagnostic antigens found by proteomic profiling. In particular, the extracellular domains of invariant surface glycoprotein 65 (ISG65), variant surface glycoproteins VSG LiTat 1.3 and VSG LiTat 1.5 were fused with C-terminal histidine tags and expressed as soluble proteins in the medium of cultured, recombinant L. tarentolae. Using affinity chromatography, on average 10 mg/L of recombinant protein was purified from cultures and subsequently tested against a panel of sera from sleeping sickness patients from controls, i.e. persons without sleeping sickness living in HAT endemic countries. The evaluation on sera from 172 T.b. gambiense human African trypanosomiasis (HAT) patients and from 119 controls showed very high diagnostic potential of the two recombinant VSG and the rISG65 fragments with areas under the curve between 0.97 and 0.98 compared to 0.98 and 0.99 with native VSG LiTat 1.3 and VSG LiTat 1.5 (statistically not different). Evaluation on sera from 78 T.b. rhodesiense HAT patients and from 100 controls showed an acceptable diagnostic potential of rISG65 with an area under the curve of 0.83. These results indicate that a combination of these recombinant antigens has the potential to be used in next generation rapid serodiagnostic tests. In addition, the L. tarentolae expression system enables simple, cheap and efficient production of recombinant kinetoplatid proteins for use in diagnostic, vaccine and drug discovery research that does not rely on animal use to generate materials.