24-hour changes in circulating prolactin, follicle-stimulating hormone, luteinizing hormone, and testosterone in young male rats subjected to calorie restriction

This work analyzes the effect of calorie restriction on the 24 h variation of pituitary-testicular function in young male Wistar rats by measuring the circulating levels of prolactin, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone. Control animals were provided an equilibrium calorie diet and the experimental animals a calorie-restriction diet equivalent to 66% of food restriction for four weeks starting on day 35 of life. Different groups of control and experimental rats were killed at 6 h intervals around the clock, beginning 1 h after light on (HALO). Compared to the control animals, the mean secretion of prolactin was augmented and that of LH and testosterone decreased in calorie-restricted rats, whereas FSH release remained unchanged. Significant changes in the 24 h secretory pattern of circulating prolactin, LH, and testosterone occurred in the calorie-restricted rats. These include the appearance of a second maximum of plasma prolactin at 21 HALO, blunting of the LH peak seen at 13 HALO, and phase-shift of the testosterone peak from 13 HALO in controls to 17 HALO in calorie-restricted rats. The significant positive correlation between individual LH and testosterone levels found in controls was no longer observed in calorie-restricted rats. Availability of nutrients presumably affects the mechanisms that modulate the circadian variation of the pituitary-gonadal axis in growing male rats.     

Repression of the RcsC-YojN-RcsB phosphorelay by the IgaA protein is a requisite for Salmonella virulence

Bacterial pathogenesis relies on regulators that activate virulence genes. Some of them act, in addition, as repressors of specific genes. Intracellular-growth-attenuator-A (IgaA) is a Salmonella enterica membrane protein that prevents overactivation of the RcsC-YojN-RcsB regulatory system. This negative control is critical for growth because disruption of the igaA gene is only possible in rcsC, yojN or rcsB strains. In this work, we examined the contribution of this regulatory circuit to virulence. Viable igaA point mutant alleles were isolated and characterized. These alleles encode IgaA variants leading to different levels of activation of the RcsC-YojN-RcsB system. IgaA-mediated repression of the RcsB-YojN-RcsC system occurred at the post-translational level, as shown by chromosomal epitope tagging of the rcsC, yojN and rcsB genes. The activity of the RcsC-YojN-RcsB system, monitored with the product of a tagged gmd-3xFLAG gene (positively regulated by RcsC-YojN-RcsB), was totally abolished by wild-type bacteria in mouse target organs. Such tight repression occurred only in vivo and was mediated by IgaA. Shutdown of the RcsC-YojN-RcsB system is a requisite for Salmonella virulence since all igaA point mutant strains were highly attenuated. The degree of attenuation correlated to that of the activation status of RcsC-YojN-RcsB. In some cases, the attenuation recorded was unprecedented, with competitive index (CI) values as low as 10(-6). Strikingly, IgaA is a protein absolutely dispensable for virulence in mutant strains having a non-functional RcsC-YojN-RcsB system. To our knowledge, IgaA exemplifies the first protein that contributes to virulence by exclusively acting as a negative regulator upon host colonization.     

Endemic flora biodiversity in the south of the Iberian Peninsula: altitudinal distribution,life forms and dispersal modes

The south of the Iberian Peninsula, with an altitudinal range varying from sea level to 3482m and annual average rainfall ranging from 206 to 2223mm, has 516 vascular endemic species or subspecies, that is, an endemicity rate of 13%. This survey deals with parameters such as species richness, originality, life forms and dispersal modes of these plants, in relation to altitudinal and rainfall gradients. Although most of the endemic plants occur between 600 and 1400m a.s.l. and in the range of 600–1000mm annual average rainfall, floristic originality (rate of endemic taxa per area unit) increases exponentially with altitude. The biological spectrum of this endemic flora does not follow the usual patterns observed either in local floras in the south of the Iberian Peninsula or in other regions of the Mediterranean Basin. Chamaephytes (46.08%) and hemicryptophytes (31.37%) are very abundant, whereas therophytes (11.96%) and phanerophytes (0.98%) are comparatively rare. There is a statistically significant correlation between life form and both altitudinal and rainfall gradients. Chamaephytes reach their highest density rates within 1400–2000m a.s.l., but these records tend to decrease as rainfall rates increase. Abundance of hemicryptophytes is directly dependent on rainfall rates and inversely dependent on temperature. The altitudinal distribution pattern of therophytes is opposite to that of hemicryptophytes, but there is no clear correlation as far as rainfall gradient is concerned. Considering both the endemic plants as a whole and each of the life form groups, the relationships between the dispersal modes used and the altitudinal and rainfall gradients are analysed. Up to 44.51% of the endemic plants do not present evident adaptations to promote the dispersion of their diaspores. However, only in the group of therophytes, whose occurrence is positively related to areas of minor altitude, does this difficulty of dispersion play a significant role in the maintenance of stenochory.     

Immunization in heifers with dual vaccines containing Tritrichomonas foetus and Campylobacter fetus antigens using systemic and mucosal routes

Vaccines against both bovine venereal campylobacteriosis and trichomonosis were tested. Heifers were assigned to three groups. Groups 1 (n = 21 heifers) and group 2 (n = 20) received a commercial or experimental vaccine, respectively, containing both Campylobacter fetus and Tritrichomonas foetus antigens. Group 3 (n = 21) received adjuvant alone. Preparations were injected SQ in groups 1 and 3 at days -60 and -30 (day 0 was considered the first day of a 90-day breeding period), and in group 2 SQ at days -30 and +11 and into the vaginal submucosa at day -9. Heifers were exposed to two pathogen-infected bulls for 90 days (from day 0 to day +90); furthermore, half of the heifers in each group were challenged at day +39 by an intravaginal instillation of C. fetus venerealis and T. foetus. Pregnancy diagnosis, vaginal culture, and determination of systemic IgG for both organisms were performed. Compared to controls, vaccinated heifers resisted or quickly cleared both pathogens, had a higher pregnancy rate and a higher systemic immune response during and after the breeding period. Overall, the experimental vaccine was superior to the commercial vaccine (groups 2 and 1, respectively). In conclusion, an experimental vaccine containing both C. fetus and T. foetus antigens, given both SQ and intravaginal immediately before breeding and early in the breeding season, yielded superior protection for heifers exposed to bulls harboring C. fetus and T. foetus.     

<Emphasis Type="Italic">Micrococcus luteus</Emphasis> - Survival in Amber

A growing body of evidence now supports the isolation of microorganisms from ancient materials. However, questions about the stringency of extraction methods and the genetic relatedness of isolated organisms to their closest living relatives continue to challenge the authenticity of these ancient life forms. Previous studies have successfully isolated a number of spore-forming bacteria from organic and inorganic deposits of considerable age whose survival is explained by their ability to enter suspended animation for extended periods of time. However, despite a number of putative reports, the isolation of non-spore-forming bacteria and an explanation for their survival have remained enigmatic. Here we describe the isolation of non-spore-forming cocci from a 120-million-year-old block of amber, which by genetic, morphological, and biochemical analyses are identified as belonging to the bacterial species Micrococcus luteus. Although comparison of 16S rRNA sequences from the ancient isolates with their modern counterparts is unable to confirm the precise age of these bacteria, we demonstrate, using complementary molecular and cell biological techniques, evidence supporting the view that these (and related modern members of the genus) have numerous adaptations for survival in extreme, nutrient-poor environments, traits that will assist in this bacterias persistence and dispersal in the environment. The bacterias ability to utilize succinic acid and process terpine-related compounds, both major components of natural amber, support its survival in this oligotrophic environment.     

Validation of the Diagnostic Interview for Genetic Studies (DIGS) in Colombia

An interview tool, Diagnostic Interview for Genetic Studies (DIGS 3.0), was translated into Spanish for application in studies of psychiatric disorders in Colombia. Two Spanish translations of the original English version of DIGS were prepared and back-translated into English. A review committee verified the linguistic and cultural equivalence of the translations. The evaluator and test-retest reliability were assessed calculating Cohen's kappa for samples of 65 and 91 patients respectively. DIGS proved valid in both appearance and content. The confidence interval (C.I.) was excellent for schizophrenia (kappa = 0.81, C.I. 95% = 0.68-0.93), bipolar disorder (kappa = 0.87, C.I. 95% = 0.75-0.99), major depressive disorder (kappa = 0.86, C.I. 95% = 0.70-1.00), and for a normal diagnosis (kappa = 0.65, C.I. 95% = 0.41-0.89); it was good for other psychiatric diagnosis (kappa = 0.65, C.I. 95% = 0.41-0.89) and poor for schizoaffective disorder (kappa = 0.37, C.I. 95% = -0.02-0.76). Test-retest reliability was excellent for all diagnoses (kappa > 0.8), except for "other psychiatric diagnoses" (kappa = 0.64, C.I. 95% = 0.31-0.96). The Spanish translation of the DIGS was comprehensible, with face and content validity, and good test-retest and evaluator reliability. This translation will be a useful tool for genetic studies of psychiatric disorders in Latin America, particularly where schizophrenia and affective disorders are involved.     

Initial stages of microbiologically influenced tarnishing on titanium after 20 months of immersion in freshwater

This paper studies the initial stages of iridescent tarnishes on titanium heat exchanger tubes in contact with running freshwater on the river Tagus in Spain for up to 20 months. Electrochemical impedance spectroscopy (EIS), scanning electron microscopy [(SEM with energy dispersive X-ray (EDX)] and X-ray photoelectron spectroscopy (XPS) in conjunction with argon-ion sputtering were the techniques used. The EIS data indicated a capacitive behavior, showing a semicircle that was better defined as the experimental time increased, indicating a decreasing tarnishing resistance of titanium. XPS and EDX results indicated that the main elements identified were calcium, phosphorus, nitrogen, and iron. The amount of these elements was higher on the tarnished titanium specimens than on the untarnished specimens. SEM analysis showed the presence of diatoms in the iridescent tarnishes on titanium tubes.     

Endocrine correlates of sexual behavior in the Mohor gazelle (Gazella dama mhorr)

In this study, we quantitatively examined male sexual behavior in relation to fecal estrogen and progesterone concentrations in female Mohor gazelles. We investigated the hypothesis that, during natural mating, males detect cues relating to the potential for successful conception and pregnancy. Time series analysis revealed that males could detect the approach of estrus 2-3 days before female fecal estrogens and estrogen/progestagen (E/P) ratio reached their peak values. Males also paid closer attention to those females excreting higher fecal estrogen concentrations. Mounting and copulation frequencies were positively correlated with both peri-ovulatory fecal estrogen concentrations, and the frequency of pre-copulatory courtship behaviors. These data suggested that males invest their reproductive effort selectively by mating the most fertile females, assuming that estrogen is a valid index of fertility. This assumption was investigated by examining sequential phases of the reproductive cycle for evidence that oocytes and follicles produced in a more estrogenic environment would lead to the formation of the most competent corpora lutea, thereby maximizing the chance of sustaining pregnancy. Associations between sexual behavior and hormone excretion support the hypothesis that males may use this mechanism to assess female fertility.