Effect of chromium on photosystem 2 in the unicellular green alga, <Emphasis Type="Italic">Chlorella pyrenoidosa</Emphasis>

We investigated the effect of chromium (20–40 g m⁻³, 8–72 h) on the photosystem 2 (PS2) activities of Chlorella pyrenoidosa cells. By using chlorophyll fluorescence transients, thermoluminescence, oxygen polarography, and Western blot analysis for D1 protein we found that inhibition of PS2 can be accounted for by the enhanced photodestruction of the reaction centres in the cells cultivated in the presence of Cr(VI) at 25 °C in “white light” (18 W m⁻²). Hence photodestruction of D1 is caused by an enhanced oxidative stress and lipid peroxidation, as indicated by the appearance of a high-temperature thermoluminescence band.     

Four independent mutations in the feline fibroblast growth factor 5 gene determine the long-haired phenotype in domestic cats

To determine the genetic regulation of "hair length" in the domestic cat, a whole-genome scan was performed in a multigenerational pedigree in which the "long-haired" phenotype was segregating. The 2 markers that demonstrated the greatest linkage to the long-haired trait (log of the odds > or = 6) flanked an estimated 10-Mb region on cat chromosome B1 containing the Fibroblast Growth Factor 5 (FGF5) gene, a candidate gene implicated in regulating hair follicle growth cycle in other species. Sequence analyses of FGF5 in 26 cat breeds and 2 pedigrees of nonbreed cats revealed 4 separate mutations predicted to disrupt the biological activity of the FGF5 protein. Pedigree analyses demonstrated that different combinations of paired mutant FGF5 alleles segregated with the long-haired phenotype in an autosomal recessive manner. Association analyses of more than 380 genotyped breed and nonbreed cats were consistent with mutations in the FGF5 gene causing the long-haired phenotype in an autosomal recessive manner. In combination, these genomic approaches demonstrated that FGF5 is the major genetic determinant of hair length in the domestic cat.     

The serine protease domain of hepatitis C viral NS3 activates RNA helicase activity by promoting the binding of RNA substrate

Nonstructural (NS) protein 3 is a DEXH/D-box motor protein that is an essential component of the hepatitis C viral (HCV) replicative complex. The full-length NS3 protein contains two functional modules, both of which are essential in the life cycle of HCV: a serine protease domain at the N terminus and an ATPase/helicase domain (NS3hel) at the C terminus. Truncated NS3hel constructs have been studied extensively; the ATPase, nucleic acid binding, and helicase activities have been examined and NS3hel has been used as a target in the development of antivirals. However, a comprehensive comparison of NS3 and NS3hel activities has not been performed, so it remains unclear whether the protease domain plays a vital role in NS3 helicase function. Given that many DEXH/D-box proteins are activated upon interaction with cofactor proteins, it is important to establish if the protease domain acts as the cofactor for stimulating NS3 helicase function. Here we show that the protease domain greatly enhances both the direct and functional binding of RNA to NS3. Whereas electrostatics plays an important role in this process, there is a specific allosteric contribution from the interaction interface between NS3hel and the protease domain. Most importantly, we establish that the protease domain is required for RNA unwinding by NS3. Our results suggest that, in addition to its role in cleavage of host and viral proteins, the NS3 protease domain is essential for the process of viral RNA replication and, given its electrostatic contribution to RNA binding, it may also assist in packaging of the viral RNA.     

From type 2 diabetes to antioxidant activity: a systematic review of the safety and efficacy of common and cassia cinnamon bark

Common (Cinnamomum verum, C. zeylanicum) and cassia (C. aromaticum) cinnamon have a long history of use as spices and flavouring agents. A number of pharmacological and clinical effects have been observed with their use. The objective of this study was to systematically review the scientific literature for preclinical and clinical evidence of safety, efficacy, and pharmacological activity of common and cassia cinnamon. Using the principles of evidence-based practice, we searched 9 electronic databases and compiled data according to the grade of evidence found. One pharmacological study on antioxidant activity and 7 clinical studies on various medical conditions were reported in the scientific literature including type 2 diabetes (3), Helicobacter pylori infection (1), activation of olfactory cortex of the brain (1), oral candidiasis in HIV (1), and chronic salmonellosis (1). Two of 3 randomized clinical trials on type 2 diabetes provided strong scientific evidence that cassia cinnamon demonstrates a therapeutic effect in reducing fasting blood glucose by 10.3%-29%; the third clinical trial did not observe this effect. Cassia cinnamon, however, did not have an effect at lowering glycosylated hemoglobin (HbA1c). One randomized clinical trial reported that cassia cinnamon lowered total cholesterol, low-density lipoprotein cholesterol, and triglycerides; the other 2 trials, however, did not observe this effect. There was good scientific evidence that a species of cinnamon was not effective at eradicating H. pylori infection. Common cinnamon showed weak to very weak evidence of efficacy in treating oral candidiasis in HIV patients and chronic salmonellosis.     

Discrimination of Multiple Dehalococcoides Strains in a Trichloroethene Enrichment by Quantification of Their Reductive Dehalogenase Genes

While many anaerobic microbial communities are capable of reductively dechlorinating tetrachloroethene (PCE) and trichloroethene (TCE) to dichloroethene (DCE), vinyl chloride (VC), and finally ethene, the accumulation of the highly toxic intermediates, cis-DCE (cDCE) and VC, presents a challenge for bioremediation processes. Members of the genus Dehalococcoides are apparently solely responsible for dechlorination beyond DCE, but isolates of Dehalococcoides each metabolize only a subset of PCE dechlorination intermediates and the interactions among distinct Dehalococcoides strains that result in complete dechlorination are not well understood. Here we apply quantitative PCR to 16S rRNA and reductase gene sequences to discriminate and track Dehalococcoides strains in a TCE enrichment derived from soil taken from the Alameda Naval Air Station (ANAS) using a four-gene plasmid standard. This standard increased experimental accuracy such that 16S rRNA and summed reductase gene copy numbers matched to within 10%. The ANAS culture was found to contain only a single Dehalococcoides 16S rRNA gene sequence, matching that of D. ethenogenes 195, but both the vcrA and tceA reductive dehalogenase genes. Quantities of these two genes in the enrichment summed to the quantity of the Dehalococcoides 16S rRNA gene. Further, between ANAS subcultures enriched on TCE, cDCE, or VC, the relative copy number of the two dehalogenases shifted 14-fold, indicating that the genes are present in two different Dehalococcoides strains. Comparison of cell yields in VC-, cDCE-, and TCE-enriched subcultures suggests that the tceA-containing strain is responsible for nearly all of the TCE and cDCE metabolism in ANAS, whereas the vcrA-containing strain is responsible for all of the VC metabolism.     

Monitoring the Early Signs of Cognitive Decline in Elderly by Computer Games: An MRI Study

BackgroundIt is anticipated that current and future preventive therapies will likely be more effective in the early stages of dementia, when everyday functioning is not affected. Accordingly the early identification of people at risk is particularly important. In most cases, when subjects visit an expert and are examined using neuropsychological tests, the disease has already been developed. Contrary to this cognitive games are played by healthy, well functioning elderly people, subjects who should be monitored for early signs. Further advantages of cognitive games are their accessibility and their cost-effectiveness.PurposeThe aim of the investigation was to show that computer games can help to identify those who are at risk. In order to validate games analysis was completed which measured the correlations between results of the ''Find the Pairs'' memory game and the volumes of the temporal brain regions previously found to be good predictors of later cognitive decline.ResultsThere was a correlation between the number of attempts and the time required to complete the memory game and the volume of the entorhinal cortex, the temporal pole, and the hippocampus. There was also a correlation between the results of the Paired Associates Learning (PAL) test and the memory game.ConclusionsThe results gathered support the initial hypothesis that healthy elderly subjects achieving lower scores in the memory game have increased level of atrophy in the temporal brain structures and showed a decreased performance in the PAL test. Based on these results it can be concluded that memory games may be useful in early screening for cognitive decline.     

Genetic determination of the mitochondrial adenine nucleotide translocation system and ITS role in the eukaryotic cell

On integrating experimental data published previously, the following picture of the mitochondrial adenine nucleotide (AdN) translocation system is being presented: 1. The AdN translocation system serves not only to transport ATP synthesized within mitochondria into the cytosol but also to transport cytosolic ATP into the mitochondria when oxidative phosphorylation is not functioning. 2. The AdN translocator is coded for by nuclear genes and the mitochondrial protein synthesis is not involved in its formation. 3. The AdN translocation system must be preserved and functioning even in cells which could dispense with oxidative phosphorylation. It assures appropriate concentrations of intramitochondrial ATP. 4. The intramitochondrial ATP is required for normal replication of mitochondrial DNA. Tis supports the view that the mitochondrion is a self-replicating semi-autonomous organelle. 5. The appropriate concentration of ATP must be present in mitochondria to make possible cell growth or multiplication. This points to a direct or indirect role of mitochondria in the control of cell proliferation.     

Long-term effects of early parental loss due to divorce on the HPA axis

We investigated the long-term effects of divorce and early separation from one parent on HPA axis reactivity, in young adults without psychopathology. Participants were 44 young subjects, 22 whose parents divorced before they reached age 10, and 22 controls. Psychiatric symptomatology was measured with the Brief Symptom Inventory (BSI), family perceived stress by the Dyadic Adjustment Scale (DAS), and bonding by the Parental Bonding Instrument (PBI). Assessment of HPA axis function included baseline morning cortisol and ACTH and cortisol response to a CRH stimulation test. No baseline or stimulated group differences were observed for ACTH. Cortisol levels were consistently but insignificantly lower in the divorce group throughout the CRH stimulation reaching statistical significance only at 5 min (p<0.03). Group by time effect reached a trend level (p<0.06). A correlation was found between psychiatric symptomatology and PBI scores; however, both parameters did not correlate with HPA axis activity. A significant correlation was found between DAS scores and ACTH. A regression model revealed a contributing effect for both family stress and child-parent bonding to stimulated ACTH levels. These preliminary findings suggest that even in the absence of adult psychopathology, a history of childhood separation from one parent due to divorce may lead to detectable, albeit mild, long-term alterations in HPA axis activity. Furthermore, they suggest that level of stress at home and parental bonding are important determinants of this effect. It is likely that divorce has significant and sustained effects on children's HPA axis only in the context of a traumatic separation.