Diversity and evolution of leaflet anatomical characters in the Pterocarpus clade (Fabaceae: Papilionoideae)

Journal of Plant Research - The Pterocarpus clade includes 23 genera previously attributed to different Fabaceae tribes. The recent rearrangements of many genera in the clade do not recognize...     

Catecholamine and MHPG plasma levels,platelet MAO activity,and3H-imipramine binding in heroin and cocaine addicts

This work evaluated in a population of heroin and heroin plus cocaine human addicts:

1. Norepinephrine (NE), epinephrine (Epi), and 3-methoxy-4-hydroxyphenylglycol (MHPG) (the principal metabolite of brain NE) plasma levels;
2. Monoamine oxidase (MAO) activity; and
3. ³H-imipramine specific binding to the amine carrier in platelets.

NE plasma levels were significantly lower in the short-term heroin user groups (1–3 and 4–6 yr), a finding not observed in both the long-term heroin user (>6 yr) and heroin plus cocaine user (>6 yr) groups. Epi levels changed in a similar manner, except that a significant increase was noted in heroin plus cocaine abusers. Conversely, dopamine and MHPG plasma levels increased with the duration of heroin use, and even more with cocaine abuse. Platelet MAO activity increased in all groups. Specific³H-imipramine binding sites showed an increase after 3 yr of heroin abuse and in all heroin plus cocaine addicts. In conclusion, short-term use of heroin decreases NE or Epi release, but with prolonged use, a slow adpatation occurs. In contrast, cocaine inhibits the neuronal Epi uptake, even in a situation of long duration of abuse. Probably the amine levels additionally regulate the amine carrier, resulting in changes that show a different pattern from major depression. These drugs of abuse may also influence directly or indirectly related enzymatic systems.     

Commitment to the First Cortical Reorganization During Conjugation in Stylonychia mytilus: An Argument for Homology with Cortical Development During Binary Fission

The asexual nature of the first cortical reorganization of conjugation in Stylonychia was analyzed by comparing the effect of amputation performed at different stages of early conjugation to that performed on vegetative cells at different stages of the cell cycle. Amputation of vegetative cells delineated a point of commitment to binary fission at 0.51–0.57 of the cell cycle. Cells amputated before this point were induced to undergo the regenerative mode of asexual development, but those amputated after this point continued with binary fission. In parallel, during conjugation a similar commitment was made around the time of formation of tight mating-pairs: early conjugants amputated around this time might undergo regeneration, and those operated on after this stage continued with the first cortical reorganization as in typical conjugants. The two mates of a pair might differ in their response to amputation, suggesting that the timing of commitment to the first cortical reorganization is not related to the events of conjugation, but rather is individually determined in the vegetative cycle of the cells before they pair up in mating. These observations provide support for the notion that the first cortical reorganization of conjugants is homologous to the asexual mode of cortical development in dividers, according to the theory of developmental heterochrony in the sexual reproduction of hypotrichs. The timing of commitment to the first cortical reorganization was found to temporally correlate with the entrance of the micronuclei into meiosis. Since the first cortical reorganization can proceed without the micronucleus, this raises the possibility that initiation of micronuclear meiosis is closely coupled with, and may be determined by, the commitment to the first cortical reorganization.     

Notes on the vegetation of Amazonia II. The dispersal of plants in Amazonian white sand campinas: The campinas as functional islands

The dispersal mechanisms of 37 species of plants which occur on Amazonian white sand campinas were studied. 75.67 percent of the species have the potential for long distance diaspore dispersal, including 59.46 percent which are bird-dispersed. This dispersal disharmony towards long-distance dispersal and especially towards ornithochory is characteristic of islands in general. The campinas of the lower Rio Negro region of Amazonia may be treated biogeographically as islands surrounded by large areas of tropical rain forest. A total of eight dispersal types was observed and details of these mechanisms are presented. The type of germination of many of the species studied is reported for the first time.     

Control of IgE and IgG1 antibody production in mice.

The production of IgE and IgG1 was studied in untreated, thymectomized. splenectomized, anti-thymocyte serum-treated, or sublethally X-irradiated mice. Dinitrophenyl Ascaris and ovalbumin were used as antigens, and aluminum hydroxide was used as adjuvant. A suppression of IgE production was observed in adult thymectomized mice, although the kinetic pattern of the antibody response was the same as in control animals. IgG1 antibody production was not affected by thymectomy. Splenectomy did not change either IgE or IgG1 production. A single dose of rabbit anti-thymocyte serum (ATS) given 8 days after immunization inhibited IgE antibody production. The effect of ATS was dose dependent and also varied with the amount of antigen used, the immune response to high doses being more susceptible to the effect of ATS. No alteration in IgG1 production was caused by ATS even when IgE antibody formation was completely inhibited. When preceding immunization, sublethal irradiation enhanced IgE antibody formation and partially suppressed IgG1 production; applied after immunization, irradiation caused an enhancement of IgE production which was inversely proportional to the interval elapsed between the two procedures. On the other hand, the IgG1 antibody production was fairly resistant to the same treatment. The results suggest a clearcut separation between the mechanisms regulating IgE and IgG1 production in mice.     

Bacterial mesosomes: Real structures of artifacts?

The ultrastructural study of membrane organization in gram-positive bacteria related to the OsO₄ fixation conditions revealed that large, complex mesosomes are observed only when the bacteria are subjected to an initial fixation with 0.1% OsO₄ in the culture broth, as in the prefixation step of the Ryter-Kellenberger procedure. Evidence was obtained suggesting that the large mesosomes are produced by this prefixation. The kinetic study of the membrane morphological alterations occurring during the prefixation of Bacillus cereus with 0.1% OsO₄ in the culture broth showed that the amount of mesosome material increases linearly from zero to a maximum observed at 1.7 min of prefixation and that at about this time a maximum is reached for the number of mesosomes per unity of cell area and for the average individual mesosome area. The large mesosomes observed in gram-positives fixed by the complete Ryter-Kellenberger procedure would be the result of the membrane-damaging action of 0.1% OsO₄. Such damaging action was deduced from the observation that 0.1% OsO₄ quickly lyses protoplasts and induces a quick and extensive leakage of intracellular K⁺ from B. cereus and Streptococcus faeculis. In support of that interpretation is the observation that in bacteria subjected to several membrane-damaging treatments, mesosome-like structures are seen after three different fixation procedures. In bacteria initially fixed with 1% OsO₄, 4% OsO₄ or 2.5% glutaraldehyde, no large, complex mesosomes are observed, small and simple invaginations of the cytoplasmic membrane being present. The size of these minute mesosomes is inversely proportional that causes of fixation. Uranyl acetate was found among the studied fixatives the one to the rate the least damage to bacterial membranes. This fixative satisfactorily preserves protoplasts. In bacteria initially fixed with uranyl acetate no mesosomes were found. The results of the present work throw serious doubts on the existence of mesosomes, both large and small, as real structures of bacterial cells. It is proposed that a continuous cytoplasmic membrane without infoldings (mesosomes) would be the real pattern of membrane organization in gram-positives.     

A correlation between BCL-2 modifying factor,p53 and livin gene expressions in cancer colon patients

Accumulating evidence has revealed that livin gene and BCL-2 modifying factor (BMF) gene are closely associated with the initiation and progression of colon carcinoma by activating or suppressing multiple malignant processes. Those genes that can detect colon - cancer are a promising approach for cancer screening and diagnosis. This study aimed to evaluate correlation between livin, BMF and p53 genes expression in colon cancer tissues of patients included in the study, and their relationship with clinicopathological features and survival outcome in those patients. In this study, 50 pathologically diagnosed early cancer colon patients included and their tissue biopsy with 50 matched adjacent normal tissue, and 50 adenoma tissue specimens were analyzed for livin gene and BMF gene expressions using real time PCR. The relationship of those genes expressions with clinicopathological features, tumor markers, Time to Progression and overall survival for those patients were correlated in cancer colon group. In this study, there was a significant a reciprocal relationship between over expression of livin gene and down regulation of BMF and p53 genes in colon cancer cells. Livin mRNA was significantly higher, while BMF and p53 mRNA were significantly lower in colorectal cancer tissue compared to benign and normal colon tissue specimens (P < 0.001), however, this finding was absent between colon adenomas and normal mucosa. There was a significant association between up regulation of livin and down regulation of BMF and p53 expressions with more aggressive tumor (advanced TNM stage), rapid progression with metastasis and decreased overall survival in cancer colon patients, hence these genes can serve as significant prognostic markers of poor outcome in colon cancer patients. This work highlights the role of livin, BMF and p53 genes in colorectal tumorigenesis and the applicability of using those genes as a diagnostic and prognostic markers in patients with colon carcinoma and as a good target for cancer colon treatment in the future.