Synthesis and in vitro anti Mycobacterium tuberculosis activity of a series of phthalimide derivatives

New phthalimide derivatives were easily prepared through condensation of phthalic anhydride and selected amines with variable yields (70–90%). All compounds (3a–l) were evaluated against Mycobacterium tuberculosis H₃₇Rv using Alamar Blue susceptibility. The compounds 3c, 3i, and 3l have the minimum inhibitory concentrations (MICs) of 3.9, 7.8, and 5.0 μg/mL, respectively, and could be considered new lead compounds in the treatment of tuberculosis and multi-drug resistant tuberculosis.     

Changes in chromosomes and in development of cells of Sciara ocellaris induced by microsporidian infections

Two species of microsporidia distinguished by the shape of their spores were found to infect cells of various tissues of Sciara ocellaris. Although the infection affects profoundly the development of the infected cells, the interaction between the infective agents and the host cells are often well-balanced and the infected cells may survive longer than the uninfected of the same tissue. The infected cells, including their nuclei and chromosomes, increase greatly. The general reaction of the chromosomes of cells of S. ocellaris infected by microsporidia is the increase of their volume by an increase in the polyteny and the accumulation of chromosomal products between their chromonemata. The cells of the fat bodies, on the other hand, have peculiar types of reactions. Some show an increase in polyteny, frequently showing asynapsis of the entire or parts of the chromosome. Other cells show increased chromosome polyteny associated with different degrees of polyploidy. Still other infected cells develop a new type of chromosome morphology called brachy-polytene which may or may not be associated with polyploidy. Special emphasis must be given to the fact that in Diptera, which have polytene chromosomes, the relationships of the infection and the host cell may in many cases be studied thoroughly, starting with the reaction of the genes to the infective agent. It was shown that in the infected cells of the salivary gland of S. ocellaris the pattern of puffs is greatly changed; hence, this change may be the probable cause of their change in development. Infected cells of the salivary gland with enlarged and active polytene chromosomes were found in adult flies, a situation which never occurs in non-infected animals. Since the microsporidia when entering the cells of S. ocellaris do not cause degeneration of the infected cells but determine a new pattern of development, their association with host cells offers great possibilities in the study of basic problems in cell biology, mainly related to chromosomal morphology, physiology and differentiation.This paper is dedicated to our dear friend Professor Sally Hughes-Schrader for her outstanding contribution to Biology.Work supported by Grants of the Public Health Service (GM 15769), Oonselho Nacional de Pesquisas and Pundação de Amparo á Pesquisa do Estado de São Paulo Brazil.     

Anchorage-dependent surface distribution and partition during freeze-fracture of viral transmembrane glycoproteins

We have compared in the same cell type the surface distribution and partition in freeze-fractured plasma membranes of Sindbis virus glycoproteins in three different situations: (i) in permanently transformed cells that express the glycoproteins as the only viral product; (ii) in cells in which prebound viruses were forced to fuse with the plasma membrane by low pH treatment; (iii) in virus-infected cells. We report here that the viral proteins expressed on the surface of transfected cells show a uniform and unclustered distribution; conversely, in Sindbis virus-infected cells they appear clustered, regionally distributed, and always associated with budding viruses (i.e., interacting with the nucleocapsid on the cytosolic side of the membrane). Furthermore, the viral proteins expressed on transfected cells or implanted by low pH-mediated fusion partition during freeze-fracture with the exoplasmic faces of the cell plasma membranes, whereas an opposite partition is observed in infected cells. These results strongly suggest that in infected cells the clustering and the partition with the protoplasmic faces of the plasma membrane depend only on the strong "anchorage" of the glycoproteins to the nucleocapsid.     

Effect of time delay in specific growth rate on the periodic operation of bioreactors with input multiplicities

The effect of time delay in specific growth rate () on the periodic operation of bioreactors with input multiplicities is theoretically analyzed for productivity improvement. A periodic rectangular pulse is applied either in feed substrate concentration (S_f) or in dilution rate (D). Periodic operation under feed substrate concentration cycling gives improvement in productivity at lower value of ¯S_f of the two steady-state multiplicities of S_f only when the time delay in is larger. Whereas the larger value of ¯S_f gives improvement in average productivity for all values of time delay. Dilution rate (D) cycling gives an improvement in average productivity particularly for larger time delay in . This improvement in average productivity is obtained only at smaller value of dilution rate out of the two steady-state input multiplicities of D.List of Symbols D 1/h dilution rate - F memory function - g dummy variable - K_i g/l substrate inhibition constant - K_m g/l substrate saturation constant - P g/l product concentration - P_m g/l product saturation constant - Q g/(hl) product cell produced per unit time - S g/l substrate concentration - S_f g/l feed substrate concentration - S_f,p g/l feed substrate concentration during fraction of a period - X g/l biomass concentration - Y_X/S g/g cell mass yield - w variable either S or Z - Z g/l weighted average of substrate concentration Greek Letters 1/h time delay parameter - ₁ , ₂ product yield parameters, g/g and 1/h - pulse width expressed as a fraction of a period - 1/h specific growth rate - _m 1/h maximum specific growth rate - h period of oscillation - – average value     

6DMAP inhibits chromatin decondensation but not sperm histone kinase in sea urchin male pronuclei

Treatment of sea urchin eggs for 10 min prior to fertilization with the kinase inhibitor 6DMAP (6-dimethylaminopurine) reversibly inhibits swelling and loss of conical morphology of the male pronucleus. Male pronuclei inhibited with 1 mM 6DMAP for 25 min undergo phosphorylation of Sp H1 and Sp H2B histones as fully as do control nuclei. Therefore, Sp histone kinase, whose target sequences resemble those of the M-phase histone kinase, is not inhibited by 6DMAP, and Sp histone phosphorylation, although it may be necessary, is not sufficient for chromatin decondensation.     

Improved in planta genetic transformation efficiency in bitter gourd (Momordica charantia L.)

In Vitro Cellular & Developmental Biology - Plant - Production of transformed bitter gourd plants through in vitro regeneration is a laborious practice, which may also result in somaclonal...     

Identification of a complete set of functional markers for the selection of er1 powdery mildew resistance in Pisum sativum L.

Powdery mildew is the most widespread disease of pea (Pisum sativum L.) and causes severe economic losses worldwide. Recessively inherited er1 powdery mildew resistance, successfully used for decades in pea breeding programs, has recently been shown to originate from the loss of function of the PsMLO1 gene. Five er1 alleles, each corresponding to a different PsMLO1 null mutation, have been characterized to date in pea germplasm. In order to aid er1 selection, we aimed to identify functional markers which target PsMLO1 polymorphisms directly responsible for the resistant phenotype. Highly informative cleaved amplified polymorphic sequence (CAPS), derived cleaved amplified polymorphic sequence (dCAPS), sequence tagged site (STS) and high-resolution melting (HRM) markers were developed which enable the selection of each of the five er1 alleles. Taken together, the results described here provide a powerful tool for breeders, overcoming limitations of previously reported er1-linked markers due to the occurrence of recombination with the resistance locus and/or the lack of polymorphism between parental genotypes. The HRM marker er1-5/HRM54 reported here, targeting a mutagenesis-induced er1 allele recently described by us, does not require manual processing after PCR amplification, and is therefore suitable for large-scale breeding programs based on high-throughput automated screening.