Regulation of urea-uptake in the cyanobacterium Anabaena doliolum

Abstract The utilization of urea was studied in the cyanobacterium Anabaena doliolum . The uptake of urea was unaltered in the presence of ammonium. The cells receiving ATP exogenously showed an induced level of urea-uptake as compared with the control cells. Urease inhibitor acetohydroxamic acid and hydroxyurea as well as glutamate analogue, MSO, did not affect the uptake of urea. These results suggest: (1) urea and ammonia have different uptake sites, (2) urea-uptake is an energy dependent process, and (3) during short-term experiments, urea uptake is not linked with the enzyme urease or the ammonium assimilating enzyme glutamine synthetase.     

Effect of anti-mycobacterial antibodies on activation of the alternative pathway of the human complement system

Abstract Genome analysis of Pseudomonas aeruginosa was performed by digestion with rare-cutting restriction endonucleases and subsequent one- and two-dimensional field inversion gel electrophoresis (FIGE). The frequency of chromosomal recognition sites increased in the order Spe I, Dra I, Xba I, Ssp I, Nhe I. The genome size of strain PAO and the 17 IATS strains varied from 4.4 × 10⁶ to 5.4 × 10⁶ base pairs. Double restriction digests and two-dimensional FIGE provide a genome fingerprint which is useful for the identification and typing of the respective strains.     

Estimating heritability using family-pooled phenotypic and genotypic data: a simulation study applied to aquaculture

Estimating heritability based on individual phenotypic and genotypic measurements can be expensive and labour-intensive in commercial aquaculture breeding. Here, the feasibility of estimating heritability using within-family means of phenotypes and allelic frequencies was investigated. Different numbers of full-sib families and family sizes across ten generations with phenotypic and genotypic information on 10 K SNPs were analysed in ten replicates. Three scenarios, representing differing numbers of pools per family (one, two and five) were considered. The results showed that using one pool per family did not reliably estimate the heritability of family means. Using simulation parameters appropriate for aquaculture, at least 200 families of 60 progeny per family divided equally in two pools per family was required to estimate the heritability of family means effectively. Although application of five pools generated more within- and between- family relationships, it reduced the number of individuals per pool and increased within-family residual variation, hence, decreased the heritability of family means. Moreover, increasing the size of pools resulted in increasing the heritability of family means towards one. In addition, heritability of family mean estimates were higher than family heritabilities obtained from Falconer’s formula due to lower intraclass correlation estimate compared to the coefficient of relationship.Subject terms: Genome evolution     

Evidence for photosynthetic independence of viral multiplication in cyanophage LPP-1 infected cyanobacterium Phormidium uncinatum

Abstract Pigment decomposition, oxygen evolution and CO₂ fixation were measured in the cyanobacterium Phormidium uncinatum after infection with cyanophage LPP-1, under light and dark conditions. A gradual decrease in para benzoquinone supported O₂ evolution, chlorophyll a and phycocyanin level were noticed after 6 h of infection. These results demonstrated decreased photosynthetic activity of the host P. uncinatum prior to the start of LPP-1 multiplication. Metabolic inhibitor investigations confirmed that the cyanophage LPP-1 multiplication was independent of host photosynthesis.     

Effect of clofibrate on peroxisomal lignoceroyl-CoA ligase activity

The effect of a 2-week clofibrate (0.5%)-fortified diet on peroxisomal palmitoyl-CoA and lignoceroyl-CoA ligases was studied. The activities of palmitoyl-CoA and lignoceroyl-CoA ligases in peroxisomes isolated from clofibrate-treated animals were 4.4- and 4.0-fold higher than those of the controls. The different degrees of increases in these two enzyme activities support the previous conclusions that in peroxisomes palmitoyl-CoA ligase and lignoceroyl-CoA ligase are different enzymes. Since clofibrate treatment increases both of these peroxisomal acyl-CoA ligase activities and normal palmitoyl-CoA ligase is the source of the partial activity for the oxidation of lignoceric acid in X-ALD, treatment with a hypolipidemic drug, which can increase human peroxisomal enzyme activities, may be helpful in lowering the amount of the pathogen, VLC fatty acids, in X-ALD.     

Clinical Significance of Circulating Serum Levels of sCD95 and TNF-α in Cytoprotection of Cervical Cancer

Background:This study correlates the serum levels of sCD95 & TNF-α with a simple cell-based assay to evaluate the capacity of the serum sample to induce apoptosis in Jurkat cells. Interlinking of these parameters can be explored to design a minimum invasive diagnostic strategy for cervical cancer (CC).Methods:Sera samples were assessed to induce apoptosis in Jurkat cells through FACS. Serum levels of sCD95 and TNF-α were measured by ELISA. JNK phosphorylation was evaluated in sera incubated Jurkat cells. Data was scrutinized through statistical analysis.Results:Significantly higher serum levels of sCD95 and lower TNF-α levels were observed in CC patients; their sera samples inhibited induction of apoptosis in Jurkat cells through reduced JNK phosphorylation. Statistical analysis linked these three parameters for the early screening of CC.Conclusion:Distinct sera levels of sCD95 & TNF-α in CC patients showed an anti-apoptotic effect, which can be considered for early detection of CC.Key Words: Apoptosis, sCD95, Jurkat Cells, Tumor Necrosis Factor-alpha, Uterine Cervical Neoplasms     

Predicting drug polypharmacology from cell morphology readouts using variational autoencoder latent space arithmetic

A variational autoencoder (VAE) is a machine learning algorithm, useful for generating a compressed and interpretable latent space. These representations have been generated from various biomedical data types and can be used to produce realistic-looking simulated data. However, standard vanilla VAEs suffer from entangled and uninformative latent spaces, which can be mitigated using other types of VAEs such as β-VAE and MMD-VAE. In this project, we evaluated the ability of VAEs to learn cell morphology characteristics derived from cell images. We trained and evaluated these three VAE variants—Vanilla VAE, β-VAE, and MMD-VAE—on cell morphology readouts and explored the generative capacity of each model to predict compound polypharmacology (the interactions of a drug with more than one target) using an approach called latent space arithmetic (LSA). To test the generalizability of the strategy, we also trained these VAEs using gene expression data of the same compound perturbations and found that gene expression provides complementary information. We found that the β-VAE and MMD-VAE disentangle morphology signals and reveal a more interpretable latent space. We reliably simulated morphology and gene expression readouts from certain compounds thereby predicting cell states perturbed with compounds of known polypharmacology. Inferring cell state for specific drug mechanisms could aid researchers in developing and identifying targeted therapeutics and categorizing off-target effects in the future.     

Structure-guided affinity maturation of a single-chain variable fragment antibody against the Fu-bc epitope of the dengue virus envelope protein

Dengue is one of the most dominant arthropod-borne viral diseases, infecting at least 390 million people every year throughout the world. Despite this, there is no effective treatment against dengue, and the only available vaccine has already been withdrawn owing to the significant adverse effects. Therefore, passive immunotherapy using monoclonal antibodies is now being sought as a therapeutic option. To date, many dengue monoclonal antibodies have been identified, most of which are serotype-specific, and only a few of which are cross-reactive. Furthermore, antibodies that cross-react within serotypes are weakly neutralizing and frequently induce antibody-dependent enhancement, which promotes viral entry and replication. Therefore, broadly neutralizing antibodies with no risk of antibody-dependent enhancement are required for the treatment of dengue. Here, we developed a single-chain variable fragment (scFv) antibody from an anti-fusion loop E53 antibody (PDB: 2IGF). We introduced previously predicted favorable complementarity-determining region (CDR) mutations into the gene encoding the scFv antibody for affinity maturation, and the resultant variants were tested in vitro against the highly conserved fusion and bc epitope of the dengue virus envelope protein. We show some of these scFv variants with two to three substitution mutations in three different CDRs possess affinity constants (K_D) ranging from 20 to 200 nM. The scFv-mutant15, containing D31L, Y105W, and S227W substitutions, showed the lowest affinity constant, (K_D = 24 ± 7 nM), approximately 100-fold lower than its parental construct. We propose that the scFv-derivative antibody may be a good candidate for the development of an effective and safe immunotherapy.     

Evaluation of Corrosion Resistance and Characterization of Ni-Cr Coated Structure Using Plasma Spray Coating for Marine Hulls

Plasmonics - Corrosion is a natural process which gradually destructs the materials with their environment by chemical or electrochemical means. Mechanized boat hull structures used in fishing were...