Is the malaria diagnosis expensive?

Malaria remains the most important of the tropical diseases, widespread throughout the tropics, but also occurring in many temperate regions. The disease causes a heavy toll of illness and death, especially among children in endemic areas. It also poses a risk to business travellers, tourists and inmigrants and imported cases of malaria are increasingly seen in non-endemic areas. We discuss here how microscopical diagnosis is essential for identifyingPlasmodium species responsible of the infection and discarding possible mixed infections. Thus, a correct treatment can be administered in 30 min, avoiding secondary stays and saving important amounts of money. Problems of drug resistance have to be distinguished from those arising due to erroneous diagnosis.     

Reentrainment in Golden Hamsters: Effect of Melatonin, Age and Neonatal Clomipramine Treatment

Golden hamsters (young: 3 month-old; old: more than 12 month-old; or neonatally treated with clomipramine - a serotonin/noradrenaline re-uptake inhibitor antidepressant) were initially entrained to a 14:10 light:dark cycle, and their reentrainment rate after a 6 h phase advance in the photoperiod was determined. Animals took between 6 and 9 days to reentrain. Melatonin (1 mg/kg, i.p.) accelerated reentrainment to the LD cycle in all groups, except for the clomipramine-treated hamsters. These results support an important accelerating effect of the pineal hormone melatonin on resynchronization, no longer observed in clomipramine-treated hamsters.     

Toxicity of hexachlorobenzene in Meriones unguiculatus: effects on thyroid and liver

The effect of in vivo administered hexachlorobenzene (HCB) on liver and thyroid was studied on Meriones unguiculatus. HCB (1.6, 4, and 16 mg/kg of body weight) has been administered orally to meriones for 30 days. At the end of the experiment, the body weight of the animals did not show significant change. However, the higher dose of HCB treatment led to a pronounced hepatic hypertrophy comparatively to controls. Histological observations revealed many cytomorphological alterations. Cellular necrosis, periportal, and centrolobular vein congestion and cytoplasmic vacuolisation were noted and correlated with the administered doses of HCB. The higher dose of HCB induced modifications in the activities of hepatic transaminases and on thyroid hormones levels: ALAT activity level was more pronounced in males (170+/-24.7 U/l vs. 52.66+/-8.29 U/l in controls) than in females (120+/-12.47 U/l vs. 56+/-5 U/l in controls). However, ASAT activity increased significantly only in females (259+/-29 U/l vs. 244.66+/-18 U/l in controls). Plasma total triiodothyronine (TT3) and total thyroxine (TT4) levels seemed to be sex-dependent in intoxicated animals, since TT4 decreased significantly in males (21.95+/-7.46 nmol/l vs. 40.59+/-1.08 nmol/l in controls) and TT3 in females (1.42+/-0.11 nmol/l vs. 3.96+/-0.48 nmol/l in controls).     

Proteome approaches combined with Fourier transform infrared spectroscopy revealed a distinctive biofilm physiology in Bordetella pertussis

Proteome analysis was combined with whole-cell metabolic fingerprinting to gain insight into the physiology of mature biofilm in Bordetella pertussis, the agent responsible for whooping cough. Recent reports indicate that B. pertussis adopts a sessile biofilm as a strategy to persistently colonize the human host. However, since research in the past mainly focused on the planktonic lifestyle of B. pertussis, knowledge on biofilm formation of this important human pathogen is still limited. Comparative studies were carried out by combining 2-DE and Fourier transform infrared (FT-IR) spectroscopy with multivariate statistical methods. These complementary approaches demonstrated that biofilm development has a distinctive impact on B. pertussis physiology. Results from MALDI-TOF/MS identification of proteins together with results from FT-IR spectroscopy revealed the biosynthesis of a putative acidic-type polysaccharide polymer as the most distinctive trait of B. pertussis life in a biofilm. Additionally, expression of proteins known to be involved in cellular regulatory circuits, cell attachment and virulence was altered in sessile cells, which strongly suggests a significant impact of biofilm development on B. pertussis pathogenesis. In summary, our work showed that the combination of proteomics and FT-IR spectroscopy with multivariate statistical analysis provides a powerful tool to gain further insight into bacterial lifestyles.     

Chaperone receptors: guiding proteins to intracellular compartments

Despite mitochondria and chloroplasts having their own genome, 99% of mitochondrial proteins (Rehling et al., Nat Rev Mol Cell Biol 5:519–530, 2004) and more than 95% of chloroplast proteins (Soll, Curr Opin Plant Biol 5:529–535, 2002) are encoded by nuclear DNA, synthesised in the cytosol and imported post-translationally. Protein targeting to these organelles depends on cytosolic targeting factors, which bind to the precursor, and then interact with membrane receptors to deliver the precursor into a translocase. The molecular chaperones Hsp70 and Hsp90 have been widely implicated in protein targeting to mitochondria and chloroplasts, and receptors capable of recognising these chaperones have been identified at the surface of both these organelles (Schlegel et al., Mol Biol Evol 24:2763–2774, 2007). The role of these chaperone receptors is not fully understood, but they have been shown to increase the efficiency of protein targeting (Young et al., Cell 112:41–50, 2003; Qbadou et al., EMBO J 25:1836–1847, 2006). Whether these receptors contribute to the specificity of targeting is less clear. A class of chaperone receptors bearing tetratricopeptide repeat domains is able to specifically bind the highly conserved C terminus of Hsp70 and/or Hsp90. Interestingly, at least of one these chaperone receptors can be found on each organelle (Schlegel et al., Mol Biol Evol 24:2763–2774, 2007), which suggests a universal role in protein targeting for these chaperone receptors. This review will investigate the role that chaperone receptors play in targeting efficiency and specificity, as well as examining recent in silico approaches to find novel chaperone receptors.     

Construction of a robust and sensitive arginine biosensor through ancestral protein reconstruction

Biosensors for signaling molecules allow the study of physiological processes by bringing together the fields of protein engineering, fluorescence imaging, and cell biology. Construction of genetically encoded biosensors generally relies on the availability of a binding “core” that is both specific and stable, which can then be combined with fluorescent molecules to create a sensor. However, binding proteins with the desired properties are often not available in nature and substantial improvement to sensors can be required, particularly with regard to their durability. Ancestral protein reconstruction is a powerful protein-engineering tool able to generate highly stable and functional proteins. In this work, we sought to establish the utility of ancestral protein reconstruction to biosensor development, beginning with the construction of an l-arginine biosensor. l-arginine, as the immediate precursor to nitric oxide, is an important molecule in many physiological contexts including brain function. Using a combination of ancestral reconstruction and circular permutation, we constructed a Förster resonance energy transfer (FRET) biosensor for l-arginine (cpFLIPR). cpFLIPR displays high sensitivity and specificity, with a K_d of ∼14 µM and a maximal dynamic range of 35%. Importantly, cpFLIPR was highly robust, enabling accurate l-arginine measurement at physiological temperatures. We established that cpFLIPR is compatible with two-photon excitation fluorescence microscopy and report l-arginine concentrations in brain tissue.     

Understanding secondary injury

Secondary injury is a term applied to the destructive and self-propagating biological changes in cells and tissues that lead to their dysfunction or death over hours to weeks after the initial insult (the "primary injury"). In most contexts, the initial injury is usually mechanical. The more destructive phase of secondary injury is, however, more responsible for cell death and functional deficits. This subject is described and reviewed differently in the literature. To biomedical researchers, systemic and tissue-level changes such as hemorrhage, edema, and ischemia usually define this subject. To cell and molecular biologists, "secondary injury" refers to a series of predominately molecular events and an increasingly restricted set of aberrant biochemical pathways and products. These biochemical and ionic changes are seen to lead to death of the initially compromised cells and "healthy" cells nearby through necrosis or apoptosis. This latter process is called "bystander damage." These viewpoints have largely dominated the recent literature, especially in studies of the central nervous system (CNS), often without attempts to place the molecular events in the context of progressive systemic and tissue-level changes. Here we provide a more comprehensive and inclusive discussion of this topic.     

Relationship between mammary morphology traits and milk yield of Sicilo-Sarde dairy sheep in Tunisia

Sicilo-Sarde is a local breed from northern Tunisia resulting from crossing Sarda and Comisana dairy sheep and is traditionally used for cheese production after lamb weaning. A sample of 52 adult Sicilo-Sarde lactating ewes was used for studying their udder morphological traits and milk yield potential during weeks 4-8 (milking-suckling period) and 10 (milking period) of lactation. Daily milk yield was estimated on a daily basis by using the double oxytocin injection method 4 h after machine-milking at d 30 and 45. Udder and teat morphology were also measured at d 45 of lactation. Cisternal area (by ultrasonography) and udder compartments (cisternal and alveolar milk) were evaluated 8 h after milking by using atosiban and oxytocin on d 72 of lactation. Milk yield averaged 0.56 ± 0.10 L/d and ewes had small (volume, 496 ± 28 mL) and healthy udders (CMT, <1), with medium sized teats (length, 18.5 ± 4.9 mm; diameter, 10.0 ± 2.0 mm) attached at 45 ± 10°. A drop in milk production (49%) was found in the transition from suckling (day 30) to milking (week 10). Udder cisterns were multilocular and small sized (half udder area, 11.6 ± 4.5 cm²), although cisternal milk accounted for 54% of the total milk in the udder. Correlation between cisternal milk and cisternal area was moderate (R² = 0.48; P < 0.05). Lag time and total milking time were 1.9 ± 0.1 and 31 ± 5 s, respectively. In conclusion, the Sicilo-Sarde ewes evaluated showed medium sized cisterns and teats which were morphologically adequate for machine milking, although milk production needs to be improved.