Escherichia coli DnaJ and GrpE heat shock proteins jointly stimulate ATPase activity of DnaK

The products of the Escherichia coli dnaK, dnaJ, and grpE heat shock genes have been previously shown to be essential for bacteriophage lambda DNA replication at all temperatures and for bacterial survival under certain conditions. DnaK, the bacterial heat shock protein hsp70 analogue and putative chaperonin, possesses a weak ATPase activity. Previous work has shown that ATP hydrolysis allows the release of various polypeptides complexed with DnaK. Here we demonstrate that the ATPase activity of DnaK can be greatly stimulated, up to 50-fold, in the simultaneous presence of the DnaJ and GrpE heat shock proteins. The presence of either DnaJ or GrpE alone results in a slight stimulation of the ATPase activity of DnaK. The action of the DnaJ and GrpE proteins may be sequential, since the presence of DnaJ alone leads to an acceleration in the rate of hydrolysis of the DnaK-bound ATP. The presence of GrpE alone increases the rate of release of bound ATP or ADP without affecting the rate of hydrolysis. The stimulation of the ATPase activity of DnaK may contribute to its more efficient recycling, and it helps explain why mutations in dnaK, dnaJ, or grpE genes often exhibit similar pleiotropic phenotypes.

The ClpX heat-shock protein of Escherichia coli, the ATP-dependent substrate specificity component of the ClpP-ClpX protease, is a novel molecular chaperone

All major classes of protein chaperones, including DnaK (the Hsp70 eukaryotic equivalent) and GroEL (the Hsp60 eukaryotic equivalent) have been found in Escherichia coli. Molecular chaperones enhance the yields of correctly folded polypeptides by preventing aggregation and even by disaggregating certain protein aggregates. Previously, we identified the ClpX heat-shock protein of E. coli because it enables the ClpP catalytic protease to degrade the bacteriophage lambda O replication protein. Here we report that ClpX alone possesses all the properties expected of a molecular chaperone protein. Specifically, it can protect the lambda O protein from heat-induced aggregation, disaggregate preformed lambda O aggregates, and even promote efficient binding of lambda O to its DNA recognition sequence. A lambda O-ClpX specific protein-protein interaction can be detected either by a modified ELISA assay or through the stimulation of ClpX's weak ATPase activity by lambda O. Unlike the behaviour of the major DnaK and GroEL chaperones, ClpX requires the presence of ATP or its non-hydrolysable analogue ATP-gamma-S for efficient interaction with other proteins including the protection of lambda O from aggregation. However, ClpX's ability to disaggregate lambda O aggregates requires hydrolysable ATP. We propose that the ClpX protein is a bona fide chaperone, whose biological role includes the maintenance of certain polypeptides in a form competent for proteolysis by the ClpP protease. Furthermore, our results suggest that the ClpX protein also performs typical chaperone protein functions independent of ClpP.

Increasing neurofilament subunit NF-M expression reduces axonal NF-H, inhibits radial growth, and results in neurofilamentous accumulation in motor neurons

The carboxy-terminal tail domains of neurofilament subunits neurofilament NF-M and NF-H have been postulated to be responsible for the modulation of axonal caliber. To test how subunit composition affects caliber, transgenic mice were generated to increase axonal NF-M. Total neurofilament subunit content in motor and sensory axons remained essentially unchanged, but increases in NF-M were offset by proportionate decreases in both NF-H and axonal cross-sectional area. Increase in NF-M did not affect the level of phosphorylation of NF-H. This indicates that (a) in vivo NF-H and NF-M compete either for coassembly with a limiting amount of NF-L or as substrates for axonal transport, and (b) NF-H abundance is a primary determinant of axonal caliber. Despite inhibition of radial growth, increase in NF-M and reduction in axonal NF-H did not affect nearest neighbor spacing between neurofilaments, indicating that cross-bridging between nearest neighbors does not play a crucial role in radial growth. Increase in NF-M did not result in an overt phenotype or neuronal loss, although filamentous swellings in perikarya and proximal axons of motor neurons were frequently found.

Jac1, a mitochondrial J-type chaperone, is involved in the biogenesis of Fe/S clusters in Saccharomyces cerevisiae

A minor Hsp70 chaperone of the mitochondrial matrix of Saccharomyces cerevisiae, Ssq1, is involved in the formation or repair of Fe/S clusters and/or mitochondrial iron metabolism. Here, we report evidence that Jac1, a J-type chaperone of the mitochondrial matrix, is the partner of Ssq1 in this process. Reduced activity of Jac1 results in a decrease in activity of Fe/S containing mitochondrial proteins and an accumulation of iron in mitochondria. Fe/S enzyme activities remain low in both jac1 and ssq1 mutant mitochondria even if normal mitochondrial iron levels are maintained. Therefore, the low activities observed are not solely due to oxidative damage caused by excess iron. Rather, these molecular chaperones likely play a direct role in the normal assembly process of Fe/S clusters.

A specialized mitochondrial molecular chaperone system: a role in formation of Fe/S centers

Mitochondria contain a specialized system of molecular chaperones that plays a critical role in the biogenesis of Fe/S centers. This Hsp70:J-protein system shows many similarities to the system found in bacteria, but the precise role of neither chaperone system has been defined. However, evidence to date suggests an interaction with the scaffold protein on which a transient Fe/S center is assembled, and thus implies a role in either assembly of the center or its transfer to recipient proteins.

Venous Thromboembolism among Hospitalized Patients with COVID-19 Undergoing Thromboprophylaxis: A Systematic Review and Meta-Analysis

Background: Preliminary evidence indicates that prophylactic-dose thromboprophylaxis may be inadequate to control the increased risk of venous thromboembolism (VTE) in patients hospitalized for coronavirus disease 2019 (COVID-19) infection. Additionally, it remains unclear whether the D-dimer measurement is useful for VTE risk stratification among COVID-19 patients. This study aimed to offer benchmark data on the incidence of VTE and to examine the difference in D-dimer levels among anticoagulated COVID-19 patients with and without VTE incident. Methods: A comprehensive literature review of PubMed from inception to May 2020 was performed for original studies that reported the frequency of VTE and death among COVID-19 patients who received thromboprophylaxis on hospitalization. The endpoints included VTE (a composite of pulmonary embolism (PE) or deep vein thrombosis (DVT)), PE, DVT, and mortality. Results: A total of 11 cohort studies were included. Among hospitalized COVID-19 patients, 23.9% (95% confidence interval (CI), 16.2% to 33.7%; I² = 93%) developed VTE despite anticoagulation. PE and DVT were detected in 11.6% (95% CI, 7.5% to 17.5%; I² = 92%) and 11.9% (95% CI, 6.3% to 21.3%; I² = 93%) of patients, respectively. Patients in the intensive care unit (ICU) had a higher risk for VTE (30.4% )95% CI, 19.6% to 43.9%)) than those in the ward (13.0% (95% CI, 5.9% to 26.3%)). The mortality was estimated at 21.3% (95% CI, 17.0% to 26.4%; I² = 53%). COVID-19 patients who developed VTE had higher D-dimer levels than those who did not develop VTE (mean difference, 2.05 µg/mL; 95% CI, 0.30 to 3.80 µg/mL; P = 0.02). Conclusions: The heightened and heterogeneous risk of VTE in COVID-19 despite prophylactic anticoagulation calls into research on the pathogenesis of thromboembolic complications and strategy of thromboprophylaxis and risk stratification. Prominent elevation of D-dimer may be associated with VTE development and can be used to identify high-risk subsets.

Role of the mitochondrial Hsp70s, Ssc1 and Ssq1, in the maturation of Yfh1

The mitochondrial matrix of the yeast Saccharomyces cerevisiae contains two molecular chaperones of the Hsp70 class, Ssc1 and Ssq1. We report that Ssc1 and Ssq1 play sequential roles in the import and maturation of the yeast frataxin homologue (Yfh1). In vitro, radiolabeled Yfh1 was not imported into ssc1-3 mutant mitochondria, remaining in a protease-sensitive precursor form. As reported earlier, the Yfh1 intermediate form was only slowly processed to the mature form in Deltassq1 mitochondria (S. A. B. Knight, N. B. V. Sepuri, D. Pain, and A. Dancis, J. Biol. Chem. 273:18389-18393, 1998). However, the intermediate form in both wild-type and Deltassq1 mitochondria was entirely within the inner membrane, as it was resistant to digestion with protease after disruption of the outer membrane. Therefore, we conclude that Ssc1, which is present in mitochondria in approximately a 1,000-fold excess over Ssq1, is required for Yfh1 import into the matrix, while Ssq1 is necessary for the efficient processing of the intermediate to the mature form in isolated mitochondria. However, the steady-state level of mature Yfh1 in Deltassq1 mitochondria is approximately 75% of that found in wild-type mitochondria, indicating that this retardation in processing does not dramatically affect cellular concentrations. Therefore, Ssq1 likely has roles in addition to facilitating the processing of Yfh1. Twofold overexpression of Ssc1 partially suppresses the cold-sensitive growth phenotype of Deltassq1 cells, as well as the accumulation of mitochondrial iron and the defects in Fe/S enzyme activities normally found in Deltassq1 mitochondria. Deltassq1 mitochondria containing twofold-more Ssc1 efficiently converted the intermediate form of Yfh1 to the mature form. This correlation between the observed processing defect and suppression of in vivo phenotypes suggests that Ssc1 is able to carry out the functions of Ssq1, but only when present in approximately a 2,000-fold excess over normal levels of Ssq1.

Traditional Chinese Medications for Knee Osteoarthritis Pain: A Meta-Analysis of Randomized Controlled Trials

Traditional Chinese medication (TCM) has analgesic and anti-inflammatory effects in patients with knee osteoarthritis (OA). We conducted the first systematic review of the best quantitative and qualitative evidence currently available in order to evaluate the effectiveness of TCM in relieving pain in knee OA. A comprehensive literature search was conducted using three English and four Chinese biomedical databases from their inception through March 1, 2015. We included randomized controlled trials of TCM for knee OA with intervention durations of at least two weeks. The effects of TCM on pain and other clinical symptoms were measured with the visual analog scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). The total effectiveness rate, which was used to assess overall pain, physical performance and wellness, was also measured. Two researchers independently extracted data on study design, population characteristics, duration, intervention, outcomes, risk of bias, and primary results. We performed a random-effects meta-analysis when appropriate. We also explored factors that could explain the heterogeneity by conducting subgroup and meta-regression analyses. Twenty-three studies, totaling 2362 subjects, met the eligibility criteria. Treatments were formulated with an average of 8 Chinese herbs and were prescribed based on the traditional Chinese diagnostic method of syndrome differentiation. The mean treatment duration was seven weeks, with oral administration occurring one to three times a day. Compared with non-steroidal anti-inflammatory drugs and intra-articular hyaluronate injections, 18 of the studies showed significantly improved VAS pain scores (Mean Difference [MD] [Formula: see text] 0.56; 95% confidence interval [CI], 0.18 to 0.94; [Formula: see text]), six of the studies showed significantly improved WOMAC pain subscale scores (MD [Formula: see text] 2.23; 95% CI, 0.56 to 3.91; [Formula: see text]), and 16 of the trials showed significantly improved total effectiveness rates (risk ratio [Formula: see text] 1.12; 95% CI, 1.05 to 1.19; [Formula: see text] 0.0003). In addition, TCM showed a lower risk of adverse events than standard western treatments. This evidence suggests that TCM is safe and effective for improving pain, function, and wellness in treatments of knee OA. However, there is inherent clinical heterogeneity (diverse TCM formulations, controls, and treatment regimens) among the included trials. Despite these limitations, the potential analgesic effects of TCM warrant further methodologically rigorous research to determine the clinical implications of TCM on pain management in knee OA.

Domains of DnaA protein involved in interaction with DnaB protein, and in unwinding the Escherichia coli chromosomal origin

DnaA protein of Escherichia coli is a sequence-specific DNA-binding protein required for the initiation of DNA replication from the chromosomal origin, oriC. It is also required for replication of several plasmids including pSC101, F, P-1, and R6K. A collection of monoclonal antibodies to DnaA protein has been produced and the primary epitopes recognized by them have been determined. These antibodies have also been examined for the ability to inhibit activities of DNA binding, ATP binding, unwinding of oriC, and replication of both an oriC plasmid, and an M13 single-stranded DNA with a proposed hairpin structure containing a DnaA protein-binding site. Replication of the latter DNA is dependent on DnaA protein by a mechanism termed ABC priming. These studies suggest regions of DnaA protein involved in interaction with DnaB protein, and in unwinding of oriC, or low-affinity binding of ATP.

Association between red blood cell distribution width and mortality and severity among patients with COVID-19: A systematic review and meta-analysis

Emerging evidence has underscored the potential usefulness of red blood cell distribution width (RDW) measurement in predicting the mortality and disease severity of COVID‐19. This study aimed to assess the association of the plasma RDW levels with adverse prognosis in COVID‐19 patients. A comprehensive literature search from inception to September 2020 was performed to harvest original studies reporting RDW on admission and clinical outcomes among patients hospitalized with COVID‐19. RDW levels were compared between cases (patients who died or developed more severe symptoms) and controls (patients who survived or developed less severe symptoms). A total of 14,866 subjects from 10 studies were included in the meta‐analysis. Higher levels of RDW were associated with adverse outcomes in COVID‐19 patients (mean differences = 0.72; 95% CI = 0.47–0.97; I² = 89.51%). Deceased patients had higher levels of RDW compared to patients who survived (mean differences = 0.93; 95% CI = 0.63–1.23; I² = 85.58%). Severely ill COVID‐19 patients showed higher levels of RDW, as opposed to patients classified to have milder symptoms (mean differences = 0.61; 95% CI = 0.28–0.94; I² = 82.18%). Elevated RDW levels were associated with adverse outcomes in COVID‐19 patients. This finding warrants further research on whether RDW could be utilized as a simple and reliable biomarker for predicting COVID‐19 severity and whether RDW is mechanistically linked with COVID‐19 pathophysiology.

Evidence for the existence of an effective interfacial tension between miscible fluids: isobutyric acid-water and 1-butanol-water in a spinning-drop tensiometer

We report definitive evidence for an effective interfacial tension between two types of miscible fluids using spinning-drop tensiometry (SDT). Isobutyric acid (IBA) and water have an upper critical solution temperature (UCST) of 26.3 degrees C. We created a drop of the IBA-rich phase in the water-rich phase below the UCST and then increased the temperature above it. Long after the fluids have reached thermal equilibrium, the drop persists. By plotting the inverse of the drop radius cubed (r(-)(3)) vs the rotation rate squared (omega(2)), we confirmed that an interfacial tension exists and estimated its value. The transition between the miscible fluids remained sharp instead of becoming more diffuse, and the drop volume decreased with time. We observed droplet breakup via the Rayleigh-Tomotika instability above the UCST when the rotation rate was decreased by 80%, again demonstrating the existence of an effective interfacial tension. When pure IBA was injected into water above the UCST, drops formed inside the main drop even as the main drop decreased in volume with time. We also studied 1-butanol in water below the solubility limit. Effective interfacial tension values measured over time were practically constant, while the interface between the two phases remains sharp as the volume of the drop declines. The effective interfacial tension was found to be insensitive to changes in temperature and always larger than the equilibrium interfacial tension. Although these results may not apply to all miscible fluids, they clearly show that an effective interfacial tension can exist and be measured by SDT for some systems.

Dual role of the mitochondrial chaperone Mdj1p in inheritance of mitochondrial DNA in yeast

Mdj1p, a homolog of the bacterial DnaJ chaperone protein, plays an essential role in the biogenesis of functional mitochondria in the yeast Saccharomyces cerevisiae. We analyzed the role of Mdj1p in the inheritance of mitochondrial DNA (mtDNA). Mitochondrial genomes were rapidly lost in a temperature-sensitive mdj1 mutant under nonpermissive conditions. The activity of mtDNA polymerase was severely reduced in the absence of functional Mdj1p at a nonpermissive temperature, demonstrating the dependence of the enzyme on Mdj1p. At a permissive temperature, the activity of mtDNA polymerase was not affected by the absence of Mdj1p. However, under these conditions, intact [rho(+)] genomes were rapidly converted to nonfunctional [rho(-)] genomes which were stably propagated in an mdj1 deletion strain. We propose that mtDNA polymerase depends on Mdj1p as a chaperone in order to acquire and/or maintain an active conformation at an elevated temperature. In addition, Mdj1p is required for the inheritance of intact mitochondrial genomes at a temperature supporting optimal growth; this second function appears to be unrelated to the function of Mdj1p in maintaining mtDNA polymerase activity.

The requirement for molecular chaperones in lambda DNA replication is reduced by the mutation pi in lambda P gene, which weakens the interaction between lambda P protein and DnaB helicase

During the initiation of lambda DNA replication, the host DnaB helicase is complexed with phage lambda P protein in order to be properly positioned near the ori lambda-lambda O initiation complex. However, the lambda P-DnaB interaction inhibits the activities of DnaB. Thus, the concerted action of bacterial heat shock proteins, DnaK, DnaJ, and GrpE, is required to activate the helicase. Wild-type phage lambda cannot grow on the E. coli dnaB, dnaK, dnaJ, and grpE mutants. However, lambda phage with a mutation pi in the lambda P gene, is able to produce progeny in these mutants as well as in the wild-type bacteria. Purified mutant lambda pi protein reveals a much lower affinity to DnaB than wild-type lambda P, and the lambda pi-DnaB complex is unstable. Also, a very low concentration of DnaK protein is sufficient to activate the helicase in a replication system based on lambda dv dsDNA. In that system, the mutant DnaK756 protein, inactive in the lambda P-dependent replication, revealed its activity in the lambda pi-dependent reaction. The lambda O-lambda P-dependent replication system based on M13 ssDNA efficiently replicates DNA in the absence of any chaperone protein, unless lambda P is substituted by the lambda pi mutant protein. Data presented in this paper explain why lambda pi phage is able to grow on wild-type and dnaK756 bacteria.

Prognostic value of hemoglobin-to-red cell distribution width ratio in cancer: a systematic review and meta-analysis

Background: The hemoglobin-to-red cell distribution width ratio (HRR) has emerged as a novel integrative biomarker predictive of overall and disease-free survival in cancer patients. This study aimed to investigate the prognostic significance of HRR in the cancer population. Methods: A literature search was performed in PubMed/MEDLINE from inception to 1 July 2021, to collect studies assessing the prognostic value of HRR in cancer patients. The primary and secondary end points were all-cause mortality and occurrence of disease progression or relapse, respectively. A meta-analytic approach was employed to estimate the pooled hazard ratio with 95% CI by fitting random-effects models. Results: A total of 11 retrospective cohort studies representing 2985 cancer patients were included. Compared with patients with high HRR, patients with low HRR had a twofold risk of all-cause mortality (hazard ratio: 2.29; 95% CI: 1.76-2.98; p < 0.0001). There was substantial heterogeneity in the association of HRR with mortality across the studies (I²: 66.8%; 95% CI: 35.3-82.9%; p = 0.0014). Similarly, low HRR was associated with a twofold risk of disease progression or relapse (hazard ratio: 2.19; 95% CI: 1.74-2.76; p < 0.0001). No significant heterogeneity was observed (I²: 16.8%; 95% CI: 0.0-60.7%; p = 0.30). Conclusion: Low HRR was associated with mortality and disease progression or relapse in patients with cancer. Further studies are required to standardize the HRR cutoff value and investigate whether HRR can be incorporated into risk assessment models for predicting adverse prognosis in cancer patients.

Legumes Protease Inhibitors as Biopesticides and Their Defense Mechanisms against Biotic Factors

Legumes are affected by biotic factors such as insects, molds, bacteria, and viruses. These plants can produce many different molecules in response to the attack of phytopathogens. Protease inhibitors (PIs) are proteins produced by legumes that inhibit the protease activity of phytopathogens. PIs are known to reduce nutrient availability, which diminishes pathogen growth and can lead to the death of the pathogen. PIs are classified according to the specificity of the mechanistic activity of the proteolytic enzymes, with serine and cysteine protease inhibitors being studied the most. Previous investigations have reported the efficacy of these highly stable proteins against diverse biotic factors and the concomitant protective effects in crops, representing a possible replacement of toxic agrochemicals that harm the environment.

Interaction of the Escherichia coli DnaA protein with bacteriophage lambda DNA

Interaction of the Escherichia coli DnaA (replication initiator) protein with restriction fragments of phage lambda DNA demonstrated differential binding of DnaA along the whole lambda DNA. Interaction of DnaA with the lambda replication region (from the promoter pR to the origin of replication, orilambda) demonstrated a strong binding of DnaA to the region around the p(o) promoter where synthesis of a short antisense oop RNA is initiated. The four sequences protected by DnaA (two 9mers and two 5mers) are not related even to a relaxed DnaA box. The pattern of protection of these four sequences and the location of three DNase I hypersensitive sites in the lambda DNA r strand, together with results of mobility shift assays and electron microscopy studies, may indicate an interaction involving DnaA monomers bound to different DNA positions on one side of the helix and the formation of higher-order nucleoprotein structures. Therefore, it is tempting to suggest that DnaA, in addition to its activity in regulation of replication and transcription, could be considered as a factor which structures certain chromosomal regions.

Outcome Expectations and Osteoarthritis: Association of Perceived Benefits of Exercise With Self-Efficacy and Depression

OBJECTIVE

Outcome expectancy is recognized as a determinant of exercise engagement and adherence. However, little is known about which factors influence outcome expectations for exercise among people with knee osteoarthritis (OA). This is the first study to examine the association of outcome expectations for exercise with demographic, physical, and psychosocial outcomes in individuals with knee OA.

METHODS

We performed a cross-sectional analysis of the baseline data from a randomized trial of tai chi versus physical therapy in participants with symptomatic knee OA. Knee pain was evaluated using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Outcome expectations for exercise, self-efficacy, depression, anxiety, stress, and social support were measured using standard instruments. Logistic regression models were utilized to determine associations with outcome expectations.

RESULTS

There were 262 participants, with a mean age of 59.8 years and a mean body mass index of 32.1 kg/m2 ; 69.1% of the participants were female, 51.5% were white, the mean disease duration was 8.6 years, and the mean WOMAC knee pain and function scores were 260.8 and 906.8, respectively. Higher outcome expectations for exercise were associated with greater self-efficacy (odds ratio [OR] 1.25 [95% confidence interval (95% CI) 1.11-1.41]; P = 0.0004), as well as with fewer depressive symptoms (OR 0.84 for each 5-point increase [95% CI 0.73-0.97]; P = 0.01). Outcome expectancy was not significantly associated with sex, race, education, pain, function, radiographic severity, social support, anxiety, or stress.

CONCLUSION

Our results suggest significant associations between outcome expectations for exercise and self-efficacy and depression. Future studies should examine how these relationships longitudinally affect long-term clinical outcomes of exercise-based treatment for knee OA.

Intercellular adhesion molecule-1 in diabetic patients with and without microalbuminuria

BACKGROUND

Nephropathy is a major complication of type 2 diabetes mellitus (T2DM) and is heralded by the insidious development of microalbuminuria (MA). It is suggested that the serum levels of Intercellular Adhesion Molecule-1 (ICAM-1) is correlated with diabetic nephropathy. In this cross-sectional study, we evaluated serum ICAM-1 level in diabetic patients with and without MA.

METHODS

A total of 187 participants were enrolled and were classified into three groups including 40 healthy controls and 2 diabetic groups with (n = 59) or without MA (n = 88). Serum levels of ICAM-1, fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol, very low density lipoprotein cholesterol and C-reactive protein (CRP) were measured in all three groups. Statistical analyses were performed using the SPSS software. A P-value less than 0.05 was considered statistically significant.

RESULTS

Serum levels of ICAM-1 were significantly higher in diabetic patients irrespective of MA. Moreover, ICAM-1 levels in patients with MA were significantly higher than patients without MA. Patients with MA had significantly higher age and blood pressure compared to those without MA (P = 0.001). Serum levels of ICAM-1 were significantly correlated with age and HbA1c.

CONCLUSIONS

Overall, serum ICAM-1 levels were significantly higher in T2DM patients with MA and it may be associated with the severity of diabetic kidney disease.

Relationships Between Anaerobic Performance, Field Tests and Game Performance of Sitting Volleyball Players

The aim of this study was to evaluate relationships between anaerobic performance, field tests, game performance and anthropometric variables of sitting volleyball players. Twenty elite Polish sitting volleyball players were tested using the 30 s Wingate Anaerobic Test for arm crank ergometer and participated in six physical field tests. Heights in position to block and to spike, as well as arm reach were measured. Players were observed during the game on the court in terms of effectiveness of the serve, block, attack, receive and defense. Pearson analysis and the Spearman’s rank correlation coefficient were used. The strongest correlations were found between the chest pass test and mean power and peak power (r=.846; p=.001 and r=.708; p=.0005, respectively), and also between the T-test and peak power (r= −.718; p=.001). Mean power correlated with the 3 m test (r= −.540; p=.014), the 5 m test (r= −.592; p=.006), and the T-test (r= −.582; p=.007). Peak power correlated with the 3 m test (r= −.632; p=.003), the 5 m test (r= −.613; p=.004), speed & agility (r= −.552; p=.012) and speed & endurance (r=−.546; p=.013). Significant correlations were observed between anthropometric parameters and anaerobic performance variables (p≤.001), and also between anthropometric parameters and field tests (p≤.05). Game performance and physical fitness of sitting volleyball players depended on their anthropometric variables: reach of arms, the position to block and to spike. The chest pass test could be used as a non-laboratory field test of anaerobic performance of sitting volleyball players.

Regulatory properties of AMP deaminases from rat tissues

1. Phosphocellulose column chromatography under double gradient conditions (phosphate and KCl) revealed two forms of AMP deaminase in rat heart and brain and a single form in the liver and skeletal muscle. 2. Kinetically all purified AMP deaminases were classified into two categories: those, which elute from the column at lower KCl and Pi concentrations, display low S0.5 value are only moderately affected by MgATP, MgGTP and Pi; and those which elute at higher KCl and Pi concentrations, display high S0.5 values and are strongly regulated by allosteric effectors. 3. Physiological significance of the occurrence of two kinetic forms of AMP deaminase in some tissues is discussed.

Importance of Downstream Processing of Natural Astaxanthin for Pharmaceutical Application

Astaxanthin (ASX) is a xanthophyll pigment considered as a nutraceutical with high antioxidant activity. Several clinical trials have shown the multiple health benefits of this molecule; therefore, it has various pharmaceutical industry applications. Commercial astaxanthin can be produced by chemical synthesis or through biosynthesis within different microorganisms. The molecule produced by the microorganisms is highly preferred due to its zero toxicity and superior therapeutic properties. However, the biotechnological production of the xanthophyll is not competitive against the chemical synthesis, since the downstream process may represent 70–80% of the process production cost. These operations denote then an opportunity to optimize the process and make this alternative more competitive. Since ASX is produced intracellularly by the microorganisms, high investment and high operational costs, like centrifugation and bead milling or high-pressure homogenization, are mainly used. In cell recovery, flocculation and flotation may represent low energy demanding techniques, whereas, after cell disruption, an efficient extraction technique is necessary to extract the highest percentage of ASX produced by the cell. Solvent extraction is the traditional method, but large-scale ASX production has adopted supercritical CO2 (SC-CO2), an efficient and environmentally friendly technology. On the other hand, assisted technologies are extensively reported since the cell disruption, and ASX extraction can be carried out in a single step. Because a high-purity product is required in pharmaceuticals and nutraceutical applications, the use of chromatography is necessary for the downstream process. Traditionally liquid-solid chromatography techniques are applied; however, the recent emergence of liquid-liquid chromatography like high-speed countercurrent chromatography (HSCCC) coupled with liquid-solid chromatography allows high productivity and purity up to 99% of ASX. Additionally, the use of SC-CO2, coupled with two-dimensional chromatography, is very promising. Finally, the purified ASX needs to be formulated to ensure its stability and bioavailability; thus, encapsulation is widely employed. In this review, we focus on the processes of cell recovery, cell disruption, drying, extraction, purification, and formulation of ASX mainly produced in Haematococcus pluvialis, Phaffia rhodozyma, and Paracoccus carotinifaciens. We discuss the current technologies that are being developed to make downstream operations more efficient and competitive in the biotechnological production process of this carotenoid.

Role of adenine nucleotides, molecular chaperones and chaperonins in stabilization of DnaA initiator protein of Escherichia coli

DnaA protein of Escherichia coli is a sequence-specific DNA binding protein required for the initiation of DNA replication from the chromosomal origin, oriC, and of several E. coli plasmids. At a moderate ionic strength, purified DnaA protein has a strong tendency to aggregate; the self-aggregate form is inactive in DNA replication. Binding of ATP or ADP to DnaA protein protected it from aggregation to maintain its replication activity. AMP or cyclic AMP had no protective effect. The molecular chaperone DnaK protected DnaA protein from aggregation with or without ATP. DnaJ and GrpE were not stimulatory. Chaperonins GroEL and GroES were also able to prevent aggregation but only in the presence of ATP. The studies presented here show that for DnaA protein to be active in the initiation of DNA replication, it must be prevented from forming a self-aggregate by the binding of adenine nucleotides, and/or by the action of molecular chaperones.

Systematic Review and Meta-Analysis of Thromboprophylaxis with Heparins Following Intracerebral Hemorrhage

BACKGROUND

 The efficacy and safety of pharmacological thromboprophylaxis in patients with intracerebral hemorrhage (ICH) remains unclear.

METHODS

 A literature search was performed to collect studies comparing the effect of thromboprophylaxis in patients with ICH. The primary endpoints were deep vein thrombosis (DVT), pulmonary embolism (PE), and hematoma expansion or rebleeding. A meta-analytic approach was employed to estimate the relative risk (RR) by fitting fixed-effects (FE) and random-effects (RE) models.

RESULTS

 A total of 28 studies representing 3,697 hospitalized patients with ICH were included. Thromboprophylaxis was initiated within 4 days following hospital presentation and continued for 10 to 14 days in most of studies. Compared with control, thromboprophylaxis was associated with a reduced risk of DVT (47/1,399 [3.4%] vs. 202/1,377 [14.7%]; FE: RR, 0.24; 95% CI, 0.18-0.32; RE: RR, 0.27; 95% CI, 0.19-0.39) as well as PE (9/953 [0.9%] vs. 37/864 [4.3%]; FE: RR, 0.33; 95% CI, 0.19-0.57; RE: RR, 0.37; 95% CI, 0.21-0.66). Thromboprophylaxis was not associated with increased risk of hematoma expansion or rebleeding (32/1,319 [2.4%] vs. 37/1,301 [2.8%]; FE: RR, 0.75; 95% CI, 0.48-1.18; RE: RR, 0.80; 95% CI, 0.49-1.30) or mortality (117/925 [12.6%] vs. 139/904 [15.4%]; FE: RR, 0.82; 95% CI, 0.65-1.03; RE: RR, 0.83; 95% CI, 0.66-1.04).

CONCLUSION

 Thromboprophylaxis was effective in preventing DVT and PE without increasing the risk of hematoma expansion or bleeding among ICH patients. Future studies should explore the long-term effects of thromboprophylaxis in this population, particularly on the functional outcomes.