The integrase family of site-specific recombinases: regional similarities and global diversity.

A combination of two methods for detecting distant relationships in protein primary sequences was used to compare the site-specific recombination proteins encoded by bacteriophage lambda, phi 80, P22, P2, 186, P4 and P1. This group of proteins exhibits an unexpectedly large diversity of sequences. Despite this diversity, all of the recombinases can be aligned in their C-terminal halves. A 40-residue region near the C terminus is particularly well conserved in all the proteins and is homologous to a region near the C terminus of the yeast 2 mu plasmid Flp protein. This family of recombinases does not appear to be related to any other site-specific recombinases. Three positions are perfectly conserved within this family: histidine, arginine and tyrosine are found at respective alignment positions 396, 399 and 433 within the well-conserved C-terminal region. We speculate that these residues contribute to the active site of this family of recombinases, and suggest that tyrosine-433 forms a transient covalent linkage to DNA during strand cleavage and rejoining.     

Skeletal muscle O2 consumption and energy metabolism during hypoxemia

We determined the relationship of O2 transport (TO2) to O2 consumption (VO2) and to changes in cellular bioenergetics in an isolated blood-perfused rabbit hindlimb preparation (n = 8) during hypoxemia. The preparations were subjected to reductions in TO2 by progressively decreasing partial pressure of arterial O2 (PaO2). At each level of PaO2 we obtained simultaneous measures of arterial and venous blood gases, venous lactate concentration, and changes in the relative concentrations of inorganic phosphate, phosphocreatine, and ATP measured with 31P magnetic resonance spectroscopy. The ratio of the change in vascular resistance (R) to the corresponding decrease in TO2 was taken as an index of vascular autoregulation with hypoxemia. Linear and logarithmic functions were fitted by least squares to the TO2-VO2 data from each experiment. TO2-VO2 relationships were characterized as O2 conforming (linear function, n = 4) or O2 regulating (logarithmic function, n = 4), depending on the goodness of fit. Those preparations showing an O2-conforming pattern had higher control VO2 (2.42 +/- 0.14 vs. 1.66 +/- 0.19 ml.min-1.kg-1; P less than 0.05) and a lesser degree of vascular autoregulation (0.07 +/- 0.03 vs. 0.21 +/- 0.02; P less than 0.01) than the O2-regulating group. Decreases in VO2 were always accompanied by increases in inorganic phosphate and lactate and decreases in phosphocreatine, indicating O2 supply limitation and anaerobic ATP production. There was no evidence of cellular adaptation to hypoxia by decreasing energy needs or of VO2 limitation by the depletion of adenine nucleotides.     

Molecular cytogenetic analysis of a duplication Xp in a male: further delineation of a possible sex influencing region on the X chromosome

We describe a male infant with severe mental retardation and autism with a duplication of the short arm of the X chromosome. Chromosome painting confirmed the origin of this X duplication. Molecular cytogenetic analysis with fluorescence in situ hybridization (FISH) identified one copy of the zinc finger protein on the X chromosome (ZFX) and two copies of the steroid sulfatase gene (STS), further delineating the breakpoints. Based on cytogenetic and molecular comparisons of cases from the literature of sex-reversal in dup(X),Y patients and our patient, we suggest that a possible secondary sexinfluencing gene involved in the regulation of sex determination or testis morphogenesis is present at the distal Xp21.1 to p21.2 region.     

Effect of neonatal monosodium glutamate on the activities of glutamate dehydrogenase and aminotransferases in the circumventricular organs of rat brain

Summary Glutamate (Glu) the major amino acid in mammalian brain and most dietary proteins possesses neurotransmitter as well as neurotoxic properties. We administered monosodium glutamate (MSG) 4 mg/g bwt, sc on postnatal day (PND) 1 through 10 to rats on alternate days or daily and sacrificed them on PND 45 or PND 90 respectively. The activities of glutamate dehydrogenase and aminotransferases were evaluated in the circumventricular organs of brain. Results show that neonatal MSG produces alterations in glutamate metabolism in blood-brain-barrier deficient regions.     

Purification, crystallization and preliminary crystallographic analysis of porcine aldose reductase

Large crystals of porcine aldose reductase have been grown from polyethylene glycol solutions. The crystals are triclinic, space-group P1, with a = 81.3 A, b = 85.9 A, c = 56.6 A, alpha = 102.3 degrees, beta = 103.3 degrees and gamma = 79.0 degrees. The crystals grow within ten days to dimensions of 0.6 mm x 0.4 mm x 0.2 mm and diffract to at least 2.5 A. There are four molecules in the unit cell related by a set of three mutually perpendicular non-crystallographic 2-fold axes.     

A simple technique for estimation ofDrechslera nodulosa (Berk. & Curt.) Subram. and Jain propagules in soil

Summary A baiting technique was developed to estimate the population ofDrechslera nodulosa (Berk. and Curt.) Subram. and Jain in soil by using susceptible ragi (Eleusine coracana Gaertn.) culms. The number of lesions developed on baited culms were reduced with the reduction in concentration ofD. nodulosa propagules in both sterilized and unsterilized soils. Based on this a standard correlation (concentrationvs infection probability) was established which was found to be quite efficient method to estimate the population in soil and to bait even when the inoculum level was 4 propagules per g of soil.     

A five‐step risk management process for geriatric dental practice during SARS‐CoV‐2 pandemic

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is an RNA virus that causes coronavirus infection (COVID‐19). COVID‐19 is a highly contagious disease transmitted through respiratory droplets, saliva and other contact routes. Within 10 months of its outbreak, SARS‐CoV‐2 has infected more than 23 million people around the world. Evidence suggests that older adults are the most vulnerable to infection and have an increased risk of mortality. Reduced immunity and underlying medical conditions make them risk‐prone and vulnerable to critical care. Older adults affected with the SARS‐CoV‐2 virus present with distinct clinical manifestations necessitating specific treatment needs and management protocols. While it is crucial to prevent the spread of novel coronavirus (2019‐nCoV), the role of oral healthcare workers in addressing the specific needs of ageing adult patients by adopting specific guidelines and appropriate infection control protocols is timely. This paper aims to develop specific guidelines and protocols for the dental management of geriatric patients during the COVID‐19 pandemic.     

Proteomic profiling of serum samples from chikungunya-infected patients provides insights into host response

Background

Chikungunya is a highly debilitating febrile illness caused by Chikungunya virus, a single-stranded RNA virus, which is transmitted by Aedes aegypti or Aedes albopictus mosquito species. The pathogenesis and host responses in individuals infected with the chikungunya virus are not well understood at the molecular level. We carried out proteomic profiling of serum samples from chikungunya patients in order to identify molecules associated with the host response to infection by this virus.

Results

Proteomic profiling of serum obtained from the infected individuals resulted in identification of 569 proteins. Of these, 63 proteins were found to be differentially expressed (≥ 2-fold) in patient as compared to control sera. These differentially expressed proteins were involved in various processes such as lipid metabolism, immune response, transport, signal transduction and apoptosis.

Conclusions

This is the first report providing a global proteomic profile of serum samples from individuals infected with the chikungunya virus. Our data provide an insight into the proteins that are involved as host response factors during an infection. These proteins include clusterin, apolipoproteins and S100A family of proteins.     

Substitution of Glutamate Residue by Lysine in the Dimerization Domain Affects DNA Binding Ability of HapR by Inducing Structural Deformity in the DNA Binding Domain

HapR has been given the status of a high cell density master regulatory protein in Vibrio cholerae. Though many facts are known regarding its structural and functional aspects, much still can be learnt from natural variants of the wild type protein. This work aims at investigating the nature of functional inertness of a HapR natural variant harboring a substitution of a conserved glutamate residue at position 117 which participates in forming a salt bridge by lysine (HapR_V2G-E¹¹⁷K). Experimental evidence presented here reveals the inability of this variant to interact with various cognate promoters by in vitro gel shift assay. Furthermore, the elution profiles of HapR_V2G-E¹¹⁷K protein along with the wild type functional HapR_V2G in size-exclusion chromatography as well as circular dichroism spectra did not reflect any significant differences in its structure, thereby indicating the intactness of dimer in the variant protein. To gain further insight into the global shape of the proteins, small angle X-ray scattering analysis (SAXS) was performed. Intriguingly, increased radius of gyration of HapR_V2G-E¹¹⁷K of 27.5 Å in comparison to the wild type protein from SAXS data analyses implied a significant alteration in the global shape of the dimeric HapR_V2G-E¹¹⁷K protein. Structure reconstruction brought forth that the DNA binding domains were substantially “parted away” in this variant. Taken together, our data illustrates that substitution of the conserved glutamate residue by lysine in the dimerization domain induces separation of the two DNA binding domains from their native-like positioning without altering the dimeric status of HapR variant.