Biochemical changes in the germinating seeds ofTrigonella foenum graecum L. in relation tos-triazine herbicides

Thes-triazine herbicides studied (atrazine and simazine) inhibited the growth of the seedlings ofTrigonella foenum graecum L.(Viciaceae). These herbicides caused a decrease in the contents of total water soluble carbohydrates and reducing sugars. Pentose sugars increased in the cotyledons. The total protein and free amino acid contents were enhanced. The activity of peroxidase was inhibited in the cotyledons, but was enhanced in the seedling axes.     

Interaction of ethidium bromide with the transport system for monovalent cations in yeast

Summary Ethidium was found to be taken up by yeast cells in a process that, at certain concentrations has the main following characteristics: a) a substrate is required; b) it presents cooperative kinetics, withn, according to the Hill equation 3; c) ethidium can be concentrated more than 100-fold; d) the uptake is inhibited by Ca²⁺; e) the uptake of the dye is inhibited by monovalent cations with a selectivity pattern similar to that observed in their transport by yeast; f) ethidium inhibits the uptake of K⁺, and, at concentrations up to about 250 m produces a competitive inhibition on the uptake of Rb⁺; and g) ethidium produces the same effects as K⁺ on respiration and the extrusion of H⁺. It is concluded that ethidium is taken up by yeast cells in a selective way by the same transport system normally employed for monovalent cation uptake.     

New germacranolides from Liatris species

Three closely related cis-Δ⁴-diepoxygermacranolides were isolated from two Liatris species. Structures of eleganin from L. elegans (Walt.) Michx, and liscundin and liscunditrin from L. secunda (Ell.) Small. were established by NMR spectrometry, chemical transformations and correlation with punctaliatrin previously isolated from L. punctata Hook. Reinvestigation of the latter species yielded another germacranolide liatripunctin whose structure is reported.     

PcoB is a defense outer membrane protein that facilitates cellular uptake of copper

Copper (Cu) is one of the most abundant trace metals in all organisms, involved in a plethora of cellular processes. Yet elevated concentrations of the element are harmful, and interestingly prokaryotes are more sensitive for environmental Cu stress than humans. Various transport systems are present to maintain intracellular Cu homeostasis, including the prokaryotic plasmid‐encoded multiprotein pco operon, which is generally assigned as a defense mechanism against elevated Cu concentrations. Here we structurally and functionally characterize the outer membrane component of the Pco system, PcoB, recovering a 2.0 Å structure, revealing a classical β‐barrel architecture. Unexpectedly, we identify a large opening on the extracellular side, linked to a considerably electronegative funnel that becomes narrower towards the periplasm, defining an ion‐conducting pathway as also supported by metal binding quantification via inductively coupled plasma mass spectrometry and molecular dynamics (MD) simulations. However, the structure is partially obstructed towards the periplasmic side, and yet flux is permitted in the presence of a Cu gradient as shown by functional characterization in vitro. Complementary in vivo experiments demonstrate that isolated PcoB confers increased sensitivity towards Cu. Aggregated, our findings indicate that PcoB serves to permit Cu import. Thus, it is possible the Pco system physiologically accumulates Cu in the periplasm as a part of an unorthodox defense mechanism against metal stress. These results point to a previously unrecognized principle of maintaining Cu homeostasis and may as such also assist in the understanding and in efforts towards combatting bacterial infections of Pco‐harboring pathogens.     

Neuronal and mixed neuronal glial tumors associated to epilepsy. A heterogeneous and related group of tumours

The group of brain tumors with mature components encompasses several pathological entities including: the ganglioneuroma; the gangliocytoma; the ganglioglioma; the desmoplastic ganglioglioma; the neurocitoma and a group of glioneuronal hamartomatous tumorous lesions, such as meningoangiomatosis. The dysembryoplastic neuroepithelial tumor is characterized by the presence of multiple cortical nodules made up of small, oligo-like cells and a myxoid pattern rich in mucopolysaccharides. Mature neuronal cells are frequently detected throughout the tumor. Most of them are associated with microhamartias in the adjacent brain and pharmacoresistant epilepsy. The excellent prognosis of the majority of these tumors and the potential for malignant transformation of the glial component in the ganglioglioma are the two most remarkable findings. Histological signs of anaplasia and greater mitotic and proliferative activities are associated with local recurrences. Atypical neurocytomas occur only exceptionally. Treatment choices are surgical resectioning and, in those cases presenting greater proliferative activity and cytological atypia, postoperative radiotherapy may be recommended. This paper reviews this heterogeneous group of neoplasms and hamartomatous lesions, pointing out presumable transitions among the different types of mixed neuronal and glial brain tumors. A single term of "mixed neuronal-glial tumors" is defended, distinguishing different subgroups of tumors, depending on the predominant cellular component.     

Role of exonic variation in chemokine receptor genes on AIDS: CCRL2 F167Y association with pneumocystis pneumonia

Chromosome 3p21–22 harbors two clusters of chemokine receptor genes, several of which serve as major or minor coreceptors of HIV-1. Although the genetic association of CCR5 and CCR2 variants with HIV-1 pathogenesis is well known, the role of variation in other nearby chemokine receptor genes remain unresolved. We genotyped exonic single nucleotide polymorphisms (SNPs) in chemokine receptor genes: CCR3, CCRL2, and CXCR6 (at 3p21) and CCR8 and CX3CR1 (at 3p22), the majority of which were non-synonymous. The individual SNPs were tested for their effects on disease progression and outcomes in five treatment-naïve HIV-1/AIDS natural history cohorts. In addition to the known CCR5 and CCR2 associations, significant associations were identified for CCR3, CCR8, and CCRL2 on progression to AIDS. A multivariate survival analysis pointed to a previously undetected association of a non-conservative amino acid change F167Y in CCRL2 with AIDS progression: 167F is associated with accelerated progression to AIDS (RH = 1.90, P = 0.002, corrected). Further analysis indicated that CCRL2-167F was specifically associated with more rapid development of pneumocystis pneumonia (PCP) (RH = 2.84, 95% CI 1.28–6.31) among four major AIDS–defining conditions. Considering the newly defined role of CCRL2 in lung dendritic cell trafficking, this atypical chemokine receptor may affect PCP through immune regulation and inducing inflammation.     

Interaction of nanoparticles and cell-penetrating peptides with skin for transdermal drug delivery

Topical or transdermal drug delivery is challenging because the skin acts as a natural and protective barrier. Therefore, several methods have been examined to increase the permeation of therapeutic molecules into and through the skin. One approach is to use the nanoparticulate delivery system. Starting with liposomes and other vesicular systems, several other types of nanosized drug carriers have been developed such as solid lipid nanoparticles, nanostructured lipid carriers, polymer-based nanoparticles and magnetic nanoparticles for dermatological applications. This review article discusses how different particulate systems can interact and penetrate into the skin barrier. In this review, the effectiveness of nanoparticles, as well as possible mode of actions of nanoparticles, is presented. In addition to nanoparticles, cell-penetrating peptide (CPP)-mediated drug delivery into the skin and the possible mechanism of CPP-derived delivery into the skin is discussed. Lastly, the effectiveness and possible mechanism of CPP-modified nanocarriers into the skin are addressed.     

Patterns of peroxidative ethane emission from submerged rice seedlings indicate that damage from reactive oxygen species takes place during submergence and is not necessarily a post-anoxic phenomenon

Using ethane as a marker for peroxidative damage to membranes by reactive oxygen species (ROS) we examined the injury of rice seedlings during submergence in the dark. It is often expressed that membrane injury from ROS is a post-submergence phenomenon occurring when oxygen is re-introduced after submergence-induced anoxia. We found that ethane production, from rice seedlings submerged for 24–72 h, was stimulated to 4–37 nl gFW⁻¹, indicating underwater membrane peroxidation. When examined a week later the seedlings were damaged or had died. On de-submergence in air, ethane production rates rose sharply, but fell back to less than 0.1 nl gFW⁻¹ h⁻¹ after 2 h. We compared submergence-susceptible and submergence-tolerant cultivars, submergence starting in the morning (more damage) and in the afternoon (less damage) and investigated different submergence durations. The seedlings showed extensive fatality whenever total ethane emission exceeded about 15 nl gFW⁻¹. Smaller amounts of ethane emission were linked to less extensive injury to leaves. Partial oxygen shortage (O₂ levels <1%) imposed for 2 h in gas phase mixtures also stimulated ethane production. In contrast, seedlings under anaerobic gas phase conditions produced no ethane until re-aerated: then a small peak was observed followed by a low, steady ethane production. We conclude that damage during submergence is not associated with extensive anoxia. Instead, injury is linked to membrane peroxidation in seedlings that are partially oxygen deficient while submerged. On return to air, further peroxidation is suppressed within about 2 h indicating effective control of ROS production not evident during submergence itself.