The Mating Call of Isoperla bipartita Aubert, 1962 (Plecoptera,Perlodidae)

The mating call of Isoperla bipartita is described. The male call is composed of 3–10 groups, each of 1–4 rubs. The times between rubs average 89.52 msec (between first and second), 43.52 msec (between second and third) and 35.28 msec (between third and fourth). The time between two groups averages 180.75 msec and varies from 142 to 290 msec. The female answer is composed of a beat and rub repeated at 479.09 msec intervals on average and interspersed between the male call groups between 94 and 184 msec (mean = 118.11 msec) after the last rub of the male group. The I. bipartita call can be considered as a ‘complex and modified pattern’ because the male produces calls of 1–4 rubs by group and the female answers overlapping the male call by percussion-rubbing-produced signals. Moreover, it is different from other studied Iberian Isoperla calls, being probably a species-specific behavioural pattern.     

Effects of a direct injection of liposoluble iron into rat striatum. Importance of the rate of iron delivery to cells

For a better understanding of the role of iron imbalance in neuropathology, a liposoluble iron complex (ferric hydroxyquinoline, FHQ) was injected into striatum of rats. The effects of two modalities of iron injections on brain damage, hydroxyl radical ( •OH) production (assessed by the salicylate method coupled to microdialysis) and tissue reactive iron level (evaluated ex vivo by the propensity of the injected structure for lipid peroxidation) were examined. Rapid injection of FHQ (10 nmoles of 5 mM FHQ pH 3 solution over 1-min period) but not that of corresponding vehicle led to extensive damage associated with increased tissue free iron level in the injected region. Conversely, neither lesion nor free iron accumulation was observed after slow FHQ injection (10 nmoles of a 100 μM FHQ pH 7 solution over 1-h period) as compared to corresponding vehicle injection. Production of •OH was induced by slow FHQ injection but not by rapid FHQ injection, probably as a result of in vivo abolition of iron-induced •OH formation by acid pH. Indeed, rapid injection of FAC pH 7 (ferric ammonium citrate, 5 mM in saline) was associated with •OH formation whereas rapid injection of FAC pH 3 did not. Our results identify the rate of iron delivery to cells as an important determinant of iron toxicity and do not support a major role for extracellular •OH in damage associated with intracerebral iron injection.     

Influence of heart failure on nucleolar organization and protein expression in human hearts

We investigate for the first time the influence of heart failure (HF) on nucleolar organization and proteins in patients with ischemic (ICM) or dilated cardiomyopathy (DCM). A total of 71 human hearts from ICM (n=38) and DCM (n=27) patients, undergoing heart transplantation and control donors (n=6), were analysed by western-blotting, RT-PCR and cell biology methods. When we compared protein levels according to HF etiology, nucleolin was increased in both ICM (117%, p<0.05) and DCM (141%, p<0.01). Moreover, mRNA expression were also upregulated in ICM (1.46-fold, p<0.05) and DCM (1.70-fold, p<0.05. Immunofluorescence studies showed that the highest intensity of nucleolin was into nucleolus (p<0.0001), and it was increased in pathological hearts (p<0.0001). Ultrastructure analysis by electron microscopy showed an increase in the nucleus and nucleolus size in ICM (17%, p<0.05 and 131%, p<0.001) and DCM (56%, p<0.01 and 69%, p<0.01). Nucleolar organization was influenced by HF irrespective of etiology, increasing fibrillar centers (p<0.001), perinucleolar chromatin (p<0.01) and dense fibrillar components (p<0.01). Finally, left ventricular function parameters were related with nucleolin levels in ischemic hearts (p<0.0001). The present study demonstrates that HF influences on morphology and organization of nucleolar components, revealing changes in the expression and in the levels of nucleolin protein.     

Temporal variation in the infection dynamics and maturation cycle of Oligogonotylus manteri (Digenea) in the cichlid fish, 'Cichlasoma' urophthalmus, from Yucatán, México

We studied the infection dynamics and maturation cycle of Oligogonotylus manteri in wild and caged 'Cichlasoma' urophthalmus, and determined the potential role of different sources of infection in its transmission in a quarry (MITZA). Metacercariae, and nongravid and gravid stages of O. manteri were present throughout 1 annual cycle. Prevalence, mean intensity, and/or aggregation values peaked around April and June in both wild and caged fish. This period of time includes the start of the rainy season, in which the water temperature reaches its maximum annual values. Because temperature is a major factor triggering 'C.' urophthalmus activity (food intake, growth, and reproduction), and O. manteri metacercariae and adults are trophically transmitted, temperature may be playing an important role in the recruitment of worms to the fish. We also determined that cercariae infect caged fish through a mechanism other than trophic transmission whereby fish consume infected snails, which has been described as the most common mode of transmission to 'C.' urophthalmus.     

Relationship of chronotype to sleep, light exposure, and work-related fatigue in student workers

Students who work during the school year face the potential of sleep deprivation and its effects, since they have to juggle between school and work responsibilities along with social life. This may leave them with less time left for sleep than their nonworking counterparts. Chronotype is a factor that may exert an influence on the sleep of student workers. Also, light and social zeitgebers may have an impact on the sleep-related problems of this population. This study aimed to document sleep, light exposure patterns, social rhythms, and work-related fatigue of student workers aged 19-21 yrs and explore possible associations with chronotype. A total of 88 student workers (mean ± SD: 20.18 ± .44 yrs of age; 36 males/52 females) wore an actigraph (Actiwatch-L; Mini-Mitter/Respironics,Bend, OR) and filled out the Social Rhythm Metric for two consecutive weeks during the school year. Also, they completed the Morningness-Eveningness Questionnaire (MEQ), Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), and Occupational Fatigue Exhaustion/Recovery Scale (OFER). Repeated and one-way analyses of variance (ANOVAs), Pearson's chi-square tests, and correlation coefficients were used for statistical comparisons. Subjects slept an average of 06:28 h/night. Actigraphic sleep parameters, such as sleep duration, sleep efficiency, wake after sleep onset, and sleep latency, did not differ between chronotypes. Results also show that evening types (n = 17) presented lower subjective sleep quality than intermediate types (n = 58) and morning types (n = 13). Moreover, evening types reported higher levels of chronic work-related fatigue, exhibited less regular social rhythms, and were exposed to lower levels of light during their waking hours (between 2 and 11 h after wake time) as compared to intermediate types and morning types. In addition, exposure to light intensities between 100 and 500 lux was lower in evening types than in intermediate types and morning types. However, bright light exposure (≥ 1000 lux) did not differ between chronotypes. In conclusion, results suggest that student workers may constitute a high-risk population for sleep deprivation. Evening types seemed to cope less well with sleep deprivation, reporting poorer sleep quality and higher levels of work-related fatigue than intermediate types and morning types. The higher chronic work-related fatigue of evening types may be linked to their attenuated level of light exposure and weaker social zeitgebers. These results add credence to the hypothesis that eveningness entails a higher risk of health-impairing behaviors.     

Hypophagia and induction of serotonin transporter gene expression in raphe nuclei of male and female rats after short-term fluoxetine treatment

Serotonin (5-HT) is one of the regulators of feeding in humans. Drugs acting on the serotoninergic system are used to treat bulimia nervosa and to enhance the effect of hypocaloric diets in overweight subjects. They act rapidly to normalise feeding when used to treat eating-related problems. To explore the role of the 5-HT transporter (serotonin transporter (SERT)) in the short-term action of serotonin selective reuptake inhibitor fluoxetine, rats were i.p. given the drug for five consecutive days. Acute administration of fluoxetine in male and female rats produced a strong reduction in food intake, an effect that held up when daily treatment was maintained for five consecutive days. This reduction translated into a diminution of body weight that was statistically significant in the case of the males. As a reflection of the body weight change in rats killed after the fifth daily drug injection, retroperitoneal fat pad also decreased; a diminution that was statistically significant in the case of male rats. In these conditions, plasma leptin levels of both male and female rats were lower than in untreated animals. While acute fluoxetine administration did not modify SERT gene expression, subchronic drug treatment increased the content of SERT mRNA in the midbrain raphe complex of both rat genders. These findings may contribute to explain the role of SERT in fluoxetine action on binging and as an adjunct to hypocaloric diets.     

Genomic GC level, optimal growth temperature, and genome size in prokaryotes

Two years ago, we showed that positive correlations between optimal growth temperature (T(opt)) and genome GC are observed in 15 out of the 20 families of prokaryotes we analyzed, thus indicating that "T(opt) is one of the factors that influence genomic GC in prokaryotes". Our results were disputed, but these criticisms were demonstrated to be mistaken and based on misconceptions. In a recent report, Wang et al. [H.C. Wang, E. Susko, A.J. Roger, On the correlation between genomic G+C content and optimal growth temperature in prokaryotes: data quality and confounding factors, Biochem. Biophys. Res. Commun. 342 (2006) 681-684] criticize our results by stating that "all previous simple correlation analyses of GC versus temperature have ignored the fact that genomic GC content is influenced by multiple factors including both intrinsic mutational bias and extrinsic environmental factors". This statement, besides being erroneous, is surprising because it applies in fact not to ours but to the authors' article. Here, we rebut the points raised by Wang et al. and review some issues that have been a matter of debate, regarding the influence of environmental factors upon GC content in prokaryotes. Furthermore, we demonstrate that the relationship that exists between genome size and GC level is valid for aerobic, facultative, and microaerophilic species, but not for anaerobic prokaryotes.     

Hemopoietic cell expression of the chemokine decoy receptor D6 is dynamic and regulated by GATA1

D6 scavenges inflammatory chemokines and is essential for the regulation of inflammatory and immune responses. Mechanisms explaining the cellular basis for D6 function have been based on D6 expression by lymphatic endothelial cells. In this study, we demonstrate that functional D6 is also expressed by murine and human hemopoietic cells and that this expression can be regulated by pro- and anti-inflammatory agents. D6 expression was highest in B cells and dendritic cells (DCs). In myeloid cells, LPS down-regulated expression, while TGF-beta up-regulated expression. Activation of T cells with anti-CD3 and soluble CD28 up-regulated mRNA expression 20-fold, while maturation of human macrophage and megakaryocyte precursors also up-regulated D6 expression. Competition assays demonstrated that chemokine uptake was D6 dependent in human leukocytes, whereas mouse D6-null cells failed to uptake and clear inflammatory chemokines. Furthermore, we present evidence indicating that D6 expression is GATA1 dependent, thus explaining D6 expression in myeloid progenitor cells, mast cells, megakaryocytes, and DCs. We propose a model for D6 function in which leukocytes, within inflamed sites, activate D6 expression and thus trigger resolution of inflammatory responses. Our data on D6 expression by circulating DCs and B cells also suggest alternative roles for D6, perhaps in the coordination of innate and adaptive immune responses. These data therefore alter our models of in vivo D6 function and suggest possible discrete, and novel, roles for D6 on lymphatic endothelial cells and leukocytes.