The chiasmatic systems in populations of two spiny leaf beetles (Coleoptera,Chrysomelidae)

The number and distribution of chiasmata per cell at diakinesis has been analyzed in four populations ofDicladispa testacea (L.) and in two ofPolyconia caroli Lepr. both having 2n=16 and a 7+Xy_p male melotic formula. Most bivalents were unichiasmate and the distal chiasma position was the one most frequently encountered. One population ofDicladispa testacea could be distinguished from the remaining ones by the total number of chiasmata per cell. This intraspecific difference is discussed in relation with the degree of isolation between the four populations and other geographical characteristics.     

The diameter of chromatin fibres depends on linker length

We have studied the diameter of chromatin fibres embedded in epoxy resins for three different materials: mouse thymus, chicken erythrocytes and sea cucumber spermatozoa. We confirm that the diameter of chromatin fibres increases with linker length, both values being influenced by the protein composition of chromatin.     

Immunolocalization of abscisic acid by monoclonal antibodies in Lavandula stoechas L. leaves

A monoclonal antibody was used to localize abscisic acid in Lavandula stoechas L. plants treated with 1 M abscisic acid. ABA localization was performed using EDC as the only fixative, which preserves antigenicity and improves the specificity of monoclonal antibodies. A relationship was observed between the effect of abscisic acid on chloroplast ultrastructure and ABA accumulation. Gold particles accumulated on swollen chloroplasts. Our findings provide cytochemical evidence that the chloroplast is a trapping compartment, and yield valuable information on the relation between chloroplast ultrastructure and ABA accumulation.Abbreviations ABA abscisic acid - BSA bovine serum albumin - EDC 1-(3-dimethyl-aminopropyl)-3 ethyl carbodiimide - IgG immunoglobulin G - mAB monoclonal antibodies - pAB polyclonal antibodies     

Humanized OKT3 antibodies: successful transfer of immune modulating properties and idiotype expression.

Antibodies that possess the Ag-binding regions of OKT3 within the context of a human framework (Hu-OKT3 Ab) offer distinct advantages for optimizing anti-CD3 mAb therapy. First, manipulation of Ab genes to produce humanized Ab that retain Ag-binding activity may circumvent antigenicity problems. Second, Ab gene engineering provides a means for modifying functional properties, including T cell activation and immune suppression. The purpose of this study was to determine the functional properties of Hu-OKT3 Ab and to compare the functional properties and idiotypes of Hu-OKT3 Ab to those of murine OKT3. Three Hu-OKT3 IgG4 Ab, a chimeric OKT3 antibody (cOKT3-1) (grafted sequences comprising all OKT3 VH and VL regions) and two complementarity determining region (CDR)-grafted antibodies, gOKT3-5 and gOKT3-6 (grafted sequences comprising only OKT3 VH and VL CDR and some framework amino acids, were analyzed. Initial studies demonstrated that the cOKT3 and gOKT3-5 Ab bound selectively to T cells and competitively inhibited OKT3-FITC binding with avidities similar to that of murine OKT3. Binding avidity of the gOKT3-6 Ab was markedly less than that of the other two Hu-OKT3 Ab. Serologic analysis suggested that cOKT3 and gOKT3-5 Ab possess idiotypes (combining sites) similar to murine OKT3. T cell activation potency of all three Hu-OKT3 Ab was assessed by proliferation, induction of activation marker expression (IL-2R and Leu 23), and lymphokine production (TNF-alpha and IFN-gamma). The cOKT3 and gOKT3-5 Ab demonstrated T cell activation potencies similar to murine OKT3 as assessed by each parameter. CD3 coating and modulation by these two Ab was effective but somewhat less potent than that observed with OKT3. Finally, cOKT3 and gOKT3-5 Ab both inhibited CTL activity comparably to murine OKT3. In conclusion, these studies indicate that gOKT3-5 and cOKT3 Ab possess immune modulating properties similar to murine OKT3 and thus offer attractive alternatives to murine OKT3 for in vivo therapy.     

Melatonin in the seasonal response of the aphid Acyrthosiphon pisum

Aphids display life cycles largely determined by the photoperiod.During the warm long-day seasons.most aphid species reproduce by viviparous parthenogenesis.The shortening of the photoperiod in autumn induces a switch to sexual reproduction.Males and sexual females mate to produce overwintering resistant eggs.In addition to this full life cycle(holocycle),there are anholocyelic lineages that do not respond to changes in photoperiod and reproduce continuously by parthenogenesis.The molecular or hormonal events that trigger the scasonal response(i.c,induction of the sexual phenotypes)are still unknown.Although circadian synthesis of melatonin is known to play a key role in vertebrate photoperiodism,the involvement of the circadian clock and/or of the hor-mone melatonin in insect seasonal responses is not so well established.Here we show that melatonin levels in the aphid Acyrthosiphon pisum are significantly higher in holocyclice aphids reared under short days than under long days,while no differences were found between anholoeyelic aphids under the same conditions.We also found that melatonin is localized in the aphid suboesophageal ganglion(SOG)and in the thoracic ganglionic mass(TGM).In analogy to vertcbrates,insect-type arylalkxylamine N-acetyltransferases(i-AANATs)are thought to play a key role in melatonin synthesis.We measured the expression of four I-AANAT genes identified in A.pisum and localized two of them in situ in the insect central nervous systems(CNS).Levels of expression of these genes were compatible with the quantities of melatonin observed.Moreover,like melatonin,expression of these genes was found in the SOG and the TGM.     

TNF-α is associated with loss of lean body mass only in already cachectic COPD patients

Background

Systemic inflammation may contribute to cachexia in patients with chronic obstructive pulmonary disease (COPD). In this longitudinal study we assessed the association between circulating C-reactive protein (CRP), tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, and IL-6 levels and subsequent loss of fat free mass and fat mass in more than 400 COPD patients over three years.

Methods

The patients, aged 40–76, GOLD stage II-IV, were enrolled in 2006/07, and followed annually. Fat free mass and fat mass indexes (FFMI & FMI) were calculated using bioelectrical impedance, and CRP, TNF-α, IL-1ß, and IL-6 were measured using enzyme immunoassays. Associations with mean change in FFMI and FMI of the four inflammatory plasma markers, sex, age, smoking, FEV₁, inhaled steroids, arterial hypoxemia, and Charlson comorbidity score were analyzed with linear mixed models.

Results

At baseline, only CRP was significantly (but weakly) associated with FFMI (r = 0.18, p < 0.01) and FMI (r = 0.27, p < 0.01). Univariately, higher age, lower FEV₁, and use of beta2-agonists were the only significant predictors of decline in FFMI, whereas smoking, hypoxemia, Charlson score, and use of inhaled steroids predicted increased loss in FMI. Multivariately, high levels of TNF-α (but not CRP, IL-1ß or IL-6) significantly predicted loss of FFMI, however only in patients with established cachexia at entry.

Conclusion

This study does not support the hypothesis that systemic inflammation is the cause of accelerated loss of fat free mass in COPD patients, but suggests a role for TNF-α in already cachectic COPD patients.     

Differential response of cycling and noncycling cells to inducers of DNA synthesis and mitosis

The objective of this study was to determine whether cells in G(0) phase are functionally distinct from those in G(1) with regard to their ability to respond to the inducers of DNA synthesis and to retard the cell cycle traverse of the G(2) component after fusion. Synchronized populations of HeLa cells in G(1) and human diploid fibroblasts in G(1) and G(0) phases were separately fused using UV-inactivated Sendai virus with HeLa cells prelabeled with [(3)H]ThdR and synchronized in S or G(2) phases. The kinetics of initiation of DNA synthesis in the nuclei of G(0) and G(1) cells residing in G(0)/S and G(1)/S dikaryons, respectively, were studied as a function of time after fusion. In the G(0)/G(2) and G(1)/G(2) fusions, the rate of entry into mitosis of the heterophasic binucleate cells was monitored in the presence of Colcemid. The effects of protein synthesis inhibition in the G(1) cells, and the UV irradiation of G(0) cells before fusion, on the rate of entry of the G(2) component into mitosis were also studied. The results of this study indicate that DNA synthesis can be induced in G(0)nuclei after fusion between G(0)- and S-phase cells, but G(0) nuclei are much slower than G(1) nuclei in responding to the inducers of DNA synthesis because the chromatin of G(0) cells is more condensed than it is in G(1) cells. A more interesting observation resulting from this study is that G(0) cells is more condensed than it is in G(1) cells. A more interesting observation resulting from this study is that G(0) cells differ from G(1) cells with regard to their effects on the cell cycle progression of the G(2) nucleus into mitosis. This difference between G(0) and G(1) cells appears to depend on certain factors, probably nonhistone proteins, present in G(1) cells but absent in G(0) cells. These factors can be induced in G(0) cells by UV irradiation and inhibited in G(1) cells by cycloheximide treatment.     

Cutting edge: membrane lymphotoxin regulates CD8(+) T cell-mediated intestinal allograft rejection.

Blocking the CD28/B7 and/or CD154/CD40 costimulatory pathways promotes long-term allograft survival in many transplant models where CD4(+) T cells are necessary for rejection. When CD8(+) T cells are sufficient to mediate rejection, these approaches fail, resulting in costimulation blockade-resistant rejection. To address this problem we examined the role of lymphotoxin-related molecules in CD8(+) T cell-mediated rejection of murine intestinal allografts. Targeting membrane lymphotoxin by means of a fusion protein, mAb, or genetic mutation inhibited rejection of intestinal allografts by CD8(+) T cells. This effect was associated with decreased monokine induced by IFN-gamma (Mig) and secondary lymphoid chemokine (SLC) gene expression within allografts and spleens respectively. Blocking membrane lymphotoxin did not inhibit rejection mediated by CD4(+) T cells. Combining disruption of membrane lymphotoxin and treatment with CTLA4-Ig inhibited rejection in wild-type mice. These data demonstrate that membrane lymphotoxin is an important regulatory molecule for CD8(+) T cells mediating rejection and suggest a strategy to avoid costimulation blockade-resistant rejection.     

Synthesis, characterization and antiproliferative studies of the enantiomers of cis-[(1,2-camphordiamine)dichloro]platinum(II) complexes

The platinum(II) complex cis-[(1S,2R,3S)-1,7,7-trimethylbicyclo[2.2.1]heptane-2,3-diamine]dichloroplatinum(II) (1) and its enantiomer (2) have been synthesized and physically and spectroscopically characterized. To obtain the enantiopure complexes the chiral pool approach was applied. The synthetic pathway has four steps, starting from (+/-)-diphenylethylenediamine (DPEDA) (3) and the natural products (1S)-camphorquinone or (1R)-camphorquinone to obtain enantiomers 1 and 2, respectively. The interaction of the Pt(II) complexes with DNA was studied by several techniques: circular dichroism, electrophoresis on agarose gel and atomic force microscopy (AFM). These studies showed differences in the degree of interaction between both enantiomers and DNA (calf thymus DNA and plasmid pBR322 DNA). The cytotoxicity of enantiomers 1 and 2 against the HL-60 cell line was studied by in vitro tests of antiproliferative activity, incubating during both 24 h and 72 h. An important difference of activity was found between both enantiomers regarding the IC50 data at 24 h of incubation. Thus, complex 1 showed to be much more active than its enantiomer 2.