Downregulation of p‐COUMAROYL ESTER 3‐HYDROXYLASE in rice leads to altered cell wall structures and improves biomass saccharification

p‐Coumaroyl ester 3‐hydroxylase (C3′H) is a key enzyme involved in the biosynthesis of lignin, a phenylpropanoid polymer that is the major constituent of secondary cell walls in vascular plants. Although the crucial role of C3′H in lignification and its manipulation to upgrade lignocellulose have been investigated in eudicots, limited information is available in monocotyledonous grass species, despite their potential as biomass feedstocks. Here we address the pronounced impacts of C3′H deficiency on the structure and properties of grass cell walls. C3′H‐knockdown lines generated via RNA interference (RNAi)‐mediated gene silencing, with about 0.5% of the residual expression levels, reached maturity and set seeds. In contrast, C3′H‐knockout rice mutants generated via CRISPR/Cas9‐mediated mutagenesis were severely dwarfed and sterile. Cell wall analysis of the mature C3′H‐knockdown RNAi lines revealed that their lignins were largely enriched in p‐hydroxyphenyl (H) units while being substantially reduced in the normally dominant guaiacyl (G) and syringyl (S) units. Interestingly, however, the enrichment of H units was limited to within the non‐acylated lignin units, with grass‐specific γ‐p‐coumaroylated lignin units remaining apparently unchanged. Suppression of C3′H also resulted in relative augmentation in tricin residues in lignin as well as a substantial reduction in wall cross‐linking ferulates. Collectively, our data demonstrate that C3′H expression is an important determinant not only of lignin content and composition but also of the degree of cell wall cross‐linking. We also demonstrated that C3′H‐suppressed rice displays enhanced biomass saccharification.     

Discovery and Evaluation of Terephthalic Acid Derivatives as Potent α4β1 Integrin Antagonists

Terephthalic acid based derivatives containing β- and γ-amino acid residues were prepared as antagonists of the leukocyte cell adhesion process that is mediated through the interaction of the very late antigen 4 (VLA-4) and the vascular cell adhesion molecule 1 (VCAM-1). The compounds 2, 10–12, 14, and 16–17 inhibited the adhesion in a cell based assay in the low and sub micromolar range.     

Neonatal Disruption of Serine Racemase Causes Schizophrenia-Like Behavioral Abnormalities in Adulthood: Clinical Rescue by D-Serine

Background

D-Serine, an endogenous co-agonist of the N-methyl-D-aspartate (NMDA) receptor, is synthesized from L-serine by serine racemase (SRR). Given the role of D-serine in both neurodevelopment and the pathophysiology of schizophrenia, we examined whether neonatal disruption of D-serine synthesis by SRR inhibition could induce behavioral abnormalities relevant to schizophrenia, in later life.

Methodology/Principal Findings

Neonatal mice (7–9 days) were injected with vehicle or phenazine methosulfate (Met-Phen: 3 mg/kg/day), an SRR inhibitor. Behavioral evaluations, such as spontaneous locomotion, novel object recognition test (NORT), and prepulse inhibition (PPI) were performed at juvenile (5–6 weeks old) and adult (10–12 weeks old) stages. In addition, we tested the effects of D-serine on PPI deficits in adult mice after neonatal Met-Phen exposure. Finally, we assessed whether D-serine could prevent the onset of schizophrenia-like behavior in these mice. Neonatal Met-Phen treatment reduced D-serine levels in the brain, 24 hours after the final dose. Additionally, this treatment caused behavioral abnormalities relevant to prodromal symptoms in juveniles and to schizophrenia in adults. A single dose of D-serine improved PPI deficits in adult mice. Interestingly, chronic administration of D-serine (900 mg/kg/day from P35 to P70) significantly prevented the onset of PPI deficits after neonatal Met-Phen exposure.

Conclusions/Significance

This study shows that disruption of D-serine synthesis during developmental stages leads to behavioral abnormalities relevant to prodromal symptoms and schizophrenia, in later life. Furthermore, early pharmacological intervention with D-serine may prevent the onset of psychosis in adult.     

Cloning and Sequencing of the Spore Germination Gene of Bacillus megaterium ATCC 12872: Similarities to the NaH-Antiporter Gene of Enterococcus hirae

The germination mutant TM-31 of Bacillus megaterium ATCC 12872, was isolated by transposon Tn917 insertional mutagenesis. Glucose, L -proline, L -leucine and KNO₃ germinated TM-31 poorly. The DNA in the region of the Tn917 insertion was cloned, and its nucleotide sequence determined. One major open reading frame was present on the cloned DNA. The hydrophobic protein encoded is presumably membrane-associated. A homology search revealed that the gene encoded in the region of the Tn917 insertion is homologous to napA of Enterococcus hirae. napA codes for the NaH-antiporter. It is hypothesized that transport of cations must play an important role in spore germination in B. megaterium ATCC 12872.     

Cytologic diagnosis of estrogen and progesterone receptors in breast imprints

OBJECTIVE: To investigate estrogen receptor (ER) and progesterone receptor (PR) levels in imprint specimens obtained at breast surgery and to compare their correlation with that of standard methods. STUDY DESIGN: Imprint specimens for cytology were obtained from 101 mass-forming lesions in 66 patients, and specimens were frozen in liquid nitrogen for later assay. The imprint specimens were immunocytochemically (ICC) stained by monoclonal antibody to ER or PR; diaminobenzidine-stained cell nuclei in clusters were regarded as positive. Tissue specimens were assayed by the standard method of dextran-coated charcoal assay (DCC) and enzyme immunoassay. RESULTS: Forty-five primary breast cancer lesions, 2 contralateral breast cancer, 49 dissected nodes and 5 benign breast lesions were collected. The correlation between DCC and ICC was 81% (82/101) for ER and 74% (66/101) for PR. That between EIA and ICC was 88% (88/99) for ER and 80% (79/100) for PR, higher than that between DCC and ICC for ER and PR. CONCLUSION: ICC assessment of ER or PR on imprint cytology is a promising clinical test with an acceptable correlation.     

Solution structure of the SWIRM domain of human histone demethylase LSD1

SWIRM is an evolutionarily conserved domain involved in several chromatin-modifying complexes. Recently, the LSD1 protein, which bears a SWIRM domain, was found to be a demethylase for Lys4-methylated histone H3. Here, we report a solution structure of the SWIRM domain of human LSD1. It forms a compact fold composed of 6 alpha helices, in which a 20 amino acid long helix (alpha4) is surrounded by 5 other short helices. The SWIRM domain structure could be divided into the N-terminal part (alpha1-alpha3) and the C-terminal part (alpha4-alpha6), which are connected to each other by a salt bridge. While the N-terminal part forms a SWIRM-specific structure, the C-terminal part adopts a helix-turn-helix (HTH)-related fold. We discuss a model in which the SWIRM domain acts as an anchor site for a histone tail.     

A preliminary genetic association study of GAD1 and GABAB receptor genes in patients with treatment-resistant schizophrenia

Molecular Biology Reports - GABAergic system dysfunction has been implicated in the etiology of schizophrenia and of cognitive impairments in particular. Patients with treatment-resistant...     

Generation of novel cationic antimicrobial peptides from natural non-antimicrobial sequences by acid-amide substitution

Background

The accessory gene regulator (agr) is a quorum sensing cluster of genes which control colonization and virulence in Staphylococcus aureus. We evaluated agr function in community- (CA) and healthcare-associated (HA) MRSA, to compare the pharmacodynamics and bactericidal activity of vancomycin against agr functional and dysfunctional HA-MRSA and CA-MRSA.

Methods

40 clinical isolates of MRSA from the Canadian Nosocomial Infection Surveillance Program were evaluated for delta-haemolysin production, as a surrogate marker of agr function. Time kill experiments were performed for vancomycin at 0 to 64 times the MIC against an initial inoculum of 10⁶ and 10⁸ cfu/ml of agr functional and dysfunctional CA-MRSA and HA-MRSA and these data were fit to a hill-type pharmacodynamic model.

Results

15% isolates were agr dysfunctional, which was higher among HA-MRSA (26.3%) versus CA-MRSA (4.76%). Against a low initial inoculum of 10⁶ cfu/ml of CA-MRSA, vancomycin pharmacodynamics were similar among agr functional and dysfunctional strains. However, against a high initial inoculum of 10⁸ cfu/ml, killing activity was notably attenuated against agr dysfunctional CA-MRSA (USA400) and HA-MRSA (USA100). CA-MRSA displayed a 20.0 fold decrease in the maximal reduction in bacterial counts (Emax) which was 3.71 log₁₀ CFU/ml for agr functional vs. 2.41 log₁₀ CFU/ml for agr dysfunctional MRSA (p = 0.0007).

Conclusions

Dysfunction in agr was less common among CA-MRSA vs. HA-MRSA. agr dysfunction demonstrated an impact on vancomycin bactericidal activity and pharmacodynamics against a high initial inoculum of CA-MRSA and HA-MRSA, which may have implications for optimal antimicrobial therapy against persistent, difficult to treat MRSA infections.