Airway mechanics, gas exchange, and blood flow in a nonlinear model of the normal human lung

Amodel integrating airway/lung mechanics, pulmonary blood flow, and gasexchange for a normal human subject executing the forced vital capacity(FVC) maneuver is presented. It requires as input the intrapleuralpressure measured during the maneuver. Selected model-generated outputvariables are compared against measured data (flow at the mouth, changein lung volume, and expired O₂ and CO₂concentrations at the mouth). A nonlinear parameter-estimation algorithm is employed to vary selected sensitive model parameters toobtain reasonable least squares fits to the data. This study indicatesthat 1) all three components of the respiratory model arenecessary to characterize the FVC maneuver; 2) changes in pulmonary blood flow rate are associated with changes in alveolar andintrapleural pressures and affect gas exchange and the time course ofexpired gas concentrations; and 3) a collapsible midairway segment must be included to match airflow during a forced expiration. Model simulations suggest that the resistances to airflow offered bythe collapsible segment and the small airways are significant throughout forced expiration; their combined effect is needed toadequately match the inspiratory and expiratory flow-volume loops.Despite the limitations of this lumped single-compartment model, aremarkable agreement with airflow and expired gas concentration measurements is obtained for normal subjects. Furthermore, the modelprovides insight into the important dynamic interactions betweenventilation and perfusion during the FVC maneuver.

     

Genus-Wide Comparative Genomics of Malassezia Delineates Its Phylogeny,Physiology, and Niche Adaptation on Human Skin

Malassezia is a unique lipophilic genus in class Malasseziomycetes in Ustilaginomycotina, (Basidiomycota, fungi) that otherwise consists almost exclusively of plant pathogens. Malassezia are typically isolated from warm-blooded animals, are dominant members of the human skin mycobiome and are associated with common skin disorders. To characterize the genetic basis of the unique phenotypes of Malassezia spp., we sequenced the genomes of all 14 accepted species and used comparative genomics against a broad panel of fungal genomes to comprehensively identify distinct features that define the Malassezia gene repertoire: gene gain and loss; selection signatures; and lineage-specific gene family expansions. Our analysis revealed key gene gain events (64) with a single gene conserved across all Malassezia but absent in all other sequenced Basidiomycota. These likely horizontally transferred genes provide intriguing gain-of-function events and prime candidates to explain the emergence of Malassezia. A larger set of genes (741) were lost, with enrichment for glycosyl hydrolases and carbohydrate metabolism, concordant with adaptation to skin’s carbohydrate-deficient environment. Gene family analysis revealed extensive turnover and underlined the importance of secretory lipases, phospholipases, aspartyl proteases, and other peptidases. Combining genomic analysis with a re-evaluation of culture characteristics, we establish the likely lipid-dependence of all Malassezia. Our phylogenetic analysis sheds new light on the relationship between Malassezia and other members of Ustilaginomycotina, as well as phylogenetic lineages within the genus. Overall, our study provides a unique genomic resource for understanding Malassezia niche-specificity and potential virulence, as well as their abundance and distribution in the environment and on human skin.     

Entry of bovine viral diarrhea virus into ovine cells occurs through clathrin-dependent endocytosis and low pH-dependent fusion

Although mechanisms of bovine viral diarrhea virus (BVDV) entry into bovine cells have been elucidated, little is known concerning pestivirus entry and receptor usage in ovine cells. In this study, we determined the entry mechanisms of BVDV-1 and BVDV-2 in sheep fetal thymus cells. Both BVDV-1 and BVDV-2 infections were inhibited completely by chlorpromazine, β-methyl cyclodextrin, sucrose, bafilomycin A1, chloroquine, and ammonium chloride. Simultaneous presence of reducing agent and low pH resulted in marked loss of BVDV infectivity. Moreover, BVDV was unable to fuse with ovine cell membrane by the presence of reducing agent or low pH alone, while combination of both led to fusion at low efficiency. Furthermore, sheep fetal thymus cells acutely infected with BVDV-1 or BVDV-2 were found protected from heterologous BVDV infection. Taken together, our results showed for the first time that entry of both BVDV-1 and BVDV-2 into ovine cells occurred through clathrin-dependent endocytosis, endosomal acidification, and low pH-dependent fusion following an activation step, besides suggesting the involvement of a common ovine cellular receptor during attachment and entry.     

Spermatogonia-specific proteins expressed in prepubertal buffalo (Bubalus bubalis) testis and their utilization for isolation and in vitro cultivation of spermatogonia

Buffalo is an economically important livestock species in Asia. Little is known about male germ line technology owing to lack of sufficient understanding regarding expression of germ- and somatic-cell specific-proteins in the testis. In this study, we identified UCHL-1 (PGP 9.5) and lectin- Dolichos biflorus agglutinin (DBA) as specific markers for spermatogonia in buffalo testis. Expression of germ-cell and pluripotency-specific proteins such as DDX4 (VASA) and POU5F1 (OCT3/4) were also present in spermatogonia. Interestingly, the expression of somatic cell-specific proteins such as VIMENTIN and GATA4 were also detected in germ cells. Using two-step enzymatic digestion followed by differential plating and Percoll density-gradient centrifugation, an approximately 55% spermatogonia-enriched cell population could be obtained from the prepubertal buffalo testis. Isolated spermatogonia could survive and proliferate in vitro in DMEM/F12 medium containing 10% fetal bovine serum in the absence of any specific growth factors for a week. Cultured spermatogonia showed DBA affinity and expressed DDX4 and POU5F1. These results may help to establish a long-term culture system for buffalo spermatogonia.     

A Case of Post Kala-Azar Dermal Leishmaniasis in India

Post kala-azar dermal leishmaniasis (PKDL) is a rare disease. This is a solitary case report from Orissa, India. We describe a case of PKDL in a 55-year-old male who presented with multiple nodular lesions over face, trunk, and extremities. The patient had been to an endemic area of kala-azar and had a previous history of leishmaniasis. Fine needle aspiration cytology samples from skin nodules revealed Leishmania amastigotes.     

Glucosamine sulfate promotes osteoblastic differentiation of MG-63 cells via anti-inflammatory effect

Glucosamine sulfate (SGlc) has been known to be effective in controlling osteoarthritis (OA) symptoms in several clinical studies. However, the mechanisms of this positive effect of SGlc in human OA still remain elusive. Therefore, first, the effects of SGlc on the differentiation of osteoblast-like MG-63 cells were investigated. Our results demonstrate that SGlc can increase ALP activity, collagen synthesis, osteocalcin secretion, and mineralization in osteoblastic cells in vitro. Furthermore, it was observed that SGlc exhibited anti-inflammatory effect on production of TNF-alpha, IL-1beta, and PGE(2) in macrophage, RAW264.7 cells. In conclusion, these results suggest that SGlc can promote cell differentiation in cultured MG-63 osteoblast cells via anti-inflammatory effect.     

A family of amphiphilic dioxidovanadium(V) hydrazone complexes as potent carbonic anhydrase inhibitors along with anti-diabetic and cytotoxic activities

BioMetals - A family of dioxidovanadium(V) complexes (1–4) of the type [Na(H2O)x]+[VVO2(HL1?4)]? (x?=?4, 4.5 and 7) where HL2? represents the dianionic form of...     

The role of regulated mRNA stability in establishing bicoid morphogen gradient in Drosophila embryonic development

The Bicoid morphogen is amongst the earliest triggers of differential spatial pattern of gene expression and subsequent cell fate determination in the embryonic development of Drosophila. This maternally deposited morphogen is thought to diffuse in the embryo, establishing a concentration gradient which is sensed by downstream genes. In most model based analyses of this process, the translation of the bicoid mRNA is thought to take place at a fixed rate from the anterior pole of the embryo and a supply of the resulting protein at a constant rate is assumed. Is this process of morphogen generation a passive one as assumed in the modelling literature so far, or would available data support an alternate hypothesis that the stability of the mRNA is regulated by active processes? We introduce a model in which the stability of the maternal mRNA is regulated by being held constant for a length of time, followed by rapid degradation. With this more realistic model of the source, we have analysed three computational models of spatial morphogen propagation along the anterior-posterior axis: (a) passive diffusion modelled as a deterministic differential equation, (b) diffusion enhanced by a cytoplasmic flow term; and (c) diffusion modelled by stochastic simulation of the corresponding chemical reactions. Parameter estimation on these models by matching to publicly available data on spatio-temporal Bicoid profiles suggests strong support for regulated stability over either a constant supply rate or one where the maternal mRNA is permitted to degrade in a passive manner.     

The mutation that makes Escherichia coli resistant to lambda P gene-mediated host lethality is located within the DNA initiator Gene dnaA of the bacterium

Earlier, we reported that the bacteriophage lambda P gene product is lethal to Escherichia coli, and the E. coli rpl mutants are resistant to this lambda P gene-mediated lethality. In this paper, we show that under the lambda P gene-mediated lethal condition, the host DNA synthesis is inhibited at the initiation step. The rpl8 mutation maps around the 83 min position in the E. coli chromosome and is 94 % linked with the dnaA gene. The rpl8 mutant gene has been cloned in a plasmid. This plasmid clone can protect the wild-type E. coli from lambda P gene-mediated killing and complements E. coli dnaAts46 at 42 degrees C. Also, starting with the wild-type dnaA gene in a plasmid, the rpl-like mutations have been isolated by in vitro mutagenesis. DNA sequencing data show that each of the rpl8, rpl12 and rpl14 mutations has changed a single base in the dnaA gene, which translates into the amino acid changes N313T, Y200N, and S246T respectively within the DnaA protein. These results have led us to conclude that the rpl mutations, which make E. coli resistant to lambda P gene-mediated host lethality, are located within the DNA initiator gene dnaA of the host.