Identification of a surface membrane proton-translocating ATPase in promastigotes of the parasitic protozoan Leishmania donovani.

ATPase activities were measured in surface membranes and mitochondria isolated from promastigotes of the parasitic protozoan Leishmania donovani. The two enzymes were differentiated on the basis of pH optima, inhibitor sensitivity and by immunochemical methods. The surface-membrane (SM-) ATPase had an activity of 100 nmol/min per mg of protein, which was optimal at pH 6.5. The enzyme was Mg2+-dependent, partially inhibited by Ca2+, and unaffected by Na+ or K+. The SM-ATPase was inhibited by orthovanadate, NN'-dicyclohexylcarbodi-imide, and N-ethylmaleimide [IC50 (concentration causing half-maximal inhibition) 7.5, 25 and 520 microM respectively]; however, it was unaffected by ouabain, azide or oligomycin. The SM-ATPase demonstrated a Km of 1.05 mM and a Vmax. of 225 nmol/min per mg of protein. Moreover, fine-structure cytochemical results demonstrated that the SM-ATPase was localized to the cytoplasmic lamina of the parasite SM. A method was devised for the isolation of SM-derived vesicles. These were used to demonstrate the proton-pumping capacity of the SM-ATPase. Cumulatively, these results constitute the first demonstration of a surface-membrane proton-translocating ATPase in a parasitic protozoan.     

Actin in striated muscle: recent insights into assembly and maintenance

Striated muscle cells are characterised by a para-crystalline arrangement of their contractile proteins actin and myosin in sarcomeres, the basic unit of the myofibrils. A multitude of proteins is required to build and maintain the structure of this regular arrangement as well as to ensure regulation of contraction and to respond to alterations in demand. This review focuses on the actin filaments (also called thin filaments) of the sarcomere and will discuss how they are assembled during myofibrillogenesis and in hypertrophy and how their integrity is maintained in the working myocardium.     

Longitudinal study of outcome of chronic fatigue syndrome.

OBJECTIVE--To examine the predictors of long term outcome for patients with the chronic fatigue syndrome. DESIGN--Cohort study. SUBJECTS--139 subjects previously enrolled in two treatment trials; 103 (74%) were reassessed a mean of 3.2 years after start of the trials. SETTING--University hospital referral centre. MAIN OUTCOME MEASURES--Age at onset, duration of illness, psychological and immunological status at initial assessment. Ongoing symptom severity, levels of disability, and immunological function at follow up. RESULTS--65 subjects had improved but only six reported no current symptoms. An alternative medical diagnosis had been made in two and psychiatric illness diagnosed in 20. The assignment of a primary psychiatric diagnosis at follow up and the strength of the belief that a physical disease process explained all symptoms at entry to the trials both predicted poor outcome. Age at onset of illness, duration of illness, neuroticism, premorbid psychiatric diagnoses, and cell mediated immune function did not predict outcome. CONCLUSION--Though most patients with the chronic fatigue syndrome improve, a substantial proportion remain functionally impaired. Psychological factors such as illness attitudes and coping style seem more important predictors of long term outcome than immunological or demographic variables.     

Communication between the PC and laboratory instruments

In this paper we describe communications between a personalcomputer and any instrument with a serial port for the purposeof collecting data or controlling equipment and a program forperforming this task. From a user-defined file, the softwarereads the communication parameters: baud rate, data bits, stopbits and partiy. The communication protocol is also read: echo,acknowledge and end-of-transmission characters. The softwarecan be used to determine the protocol, to check the integrityof the communications, and can form the basis of a program formore specific applications.     

Genetic investigation of equine recurrent uveitis in Appaloosa horses

Equine recurrent uveitis (ERU) is characterized by intraocular inflammation that often leads to blindness in horses. Appaloosas are more likely than any other breed to develop insidious ERU, distinguished by low-grade chronic intraocular inflammation, suggesting a genetic predisposition. Appaloosas are known for their white coat spotting patterns caused by the leopard complex spotting allele (LP) and the modifier PATN1. A marker linked to LP on ECA1 and markers near MHC on ECA20 were previously associated with increased ERU risk. This study aims to further investigate these loci and identify additional genetic risk factors. A GWAS was performed using the Illumina Equine SNP70 BeadChip in 91 horses. Additive mixed model approaches were used to correct for relatedness. Although they do not reach a strict Bonferroni genome-wide significance threshold, two SNPs on ECA1 and one SNP each on ECA12 and ECA29 were among the highest ranking SNPs and thus warranted further analysis (P = 1.20 × 10⁻⁵, P = 5.91 × 10⁻⁶, P = 4.91 × 10⁻⁵, P = 6.46 × 10⁻⁵). In a second cohort (n = 98), only an association with the LP allele on ECA1 was replicated (P = 5.33 × 10⁻⁵). Modeling disease risk with LP, age and additional depigmentation factors (PATN1 genotype and extent of roaning) supports an additive role for LP and suggests an additive role for PATN1. Genotyping for LP and PATN1 may help predict ERU risk (AUC = 0.83). The functional role of LP and PATN1 in ERU development requires further investigation. Testing samples across breeds with leopard complex spotting patterns and a denser set of markers is warranted to further refine the genetic components of ERU.     

Lab-Scale Biodegradation Study of BTEX under the Unsaturated Condition and Its Effect on Soil Matric Potential

Benzene, toluene, ethylbenzene, and xylene are collectively known as BTEX which contributes to volatile environmental contaminants. This present study investigates the microbial degradation of BTEX in batch and continuous soil column experiments and its effects on soil matric potential. Batch degradation experiments were performed with different initial concentrations of BTEX using the BTEX tolerant culture isolated from petroleum-contaminated soil. In batch study, the degradation pattern for single substrate showed that xylene was degraded much faster than other compounds followed by ethylbenzene, toluene, and benzene with the highest μ_max = 0.140 h^?1 during initial substrate concentration of 100 mg L^?1. Continuous degradation experiments were performed in a soil column with an inlet concentration of BTEX of about 2000 mg L^?1 under unsaturated flow in anaerobic condition. BTEX degradation pattern was studied with time and the matric potential of the soil at different parts along the length of the column were determined at the end of the experiment. In continuous degradation study, BTEX compounds were degraded with different degradation pattern and an increase in soil matric potential was observed with an increase in depth from top to bottom in the column with applied suction head. It was found that column biodegradation contributed to 69.5% of BTEX reduction and the bacterial growth increased the soil matric potential of about 34% on an average along the column height. Therefore, this study proves that it is significant to consider soil matric potential in modeling fate and transport of BTEX in unsaturated soils.