Antitumour activities of levans produced by Zymomonas mobilis strains

Levans produced by four Zymomonas mobilis strains showed antitumour activity against sarcoma 180 and Ehrlich carcinoma in Swiss albino mice. Levans from two strains (ZAP and CP4) had the highest effects. NMR analysis showed that the polymers were composed only of fructose units. The results suggested that the antineoplasic effect is associated to the polysaccharide molecular weight and that a particular molecular weight range may be responsible for this effect.     

Neuroleptic-like electroencephalographic changes in schizophrenics through biofeedback

Nine schizophrenic patients participated in a study which explored whether EEG feedback techniques could effect changes in the EEG similar to those associated with neuroleptic-induced improvement. During five sessions, each patient was presented feedback signals which continuously refected the discrepancy between characteristics of the patient's EEG power spectral profile and spectral profile characteristics associated by past research with neuroleptic induced clinical improvement. Significant within-session changes were observed for two of three EEG power spectrum bands of interest. No significant session-to-session EEG changes were observed. The results suggest that the EEG of schizophrenics can be temporarily altered, using feedback techniques, in a way that mimics the EEG changes that have been shown to occur with neuroleptic induced clinical improvement.The authors are indebted to Turan M. Itil, John W. Fredrickson, Michael Madwed, and Irene B. Francis. Senior authorship is shared equally.     

Inferring patterns of aggression from red howler monkey injuries

Venezuelan red howler monkeys in a semideciduous habitat typically survive injuries and disabilities. Intraspecific physical aggression was the most frequently observed and inferred cause of injury. Thirty-eight percent of 119 howlers of all ages examined during capture had scars or other evidence of “damage.” Overall, the sexes did not differ significantly in total number of injuries or number of individuals classified as “damaged.” The incidence of injury was not independent of age-sex class. The subadult male class had the highest percentage of “damaged” individuals. However, when total injuries per age class were examined for each sex separately, only females showed a pattern that was significantly different than expected based on age (i.e., exposure to injury factors). Subadult females experienced more injuries than expected, whereas adult females had fewer injuries. Troop status (resident troop, natal troop, or extratroop) was not significantly related to the number of injuries in adult and subadult males. Thin finding was not surprising, because adult and subadult males of all status classes are involved in aggression related to breeding competition. Extratroop females had more injuries than expected, and natal females had the fewest injuries. The higher incidence of injuries on subadult females and extratroop females is consistent with aggression-mediated emigration of some females and observed resistance to female immigration by resident females. Overall, 74% of injuries were located on anterior-ventral portions of the body, consistent with the face-to-face fighting observed in howlers. Sociobiological costs of aggression in red howlers are difficult to assess because many howlers, despite frequent and severe injury, subsequently survive and reproduce. We recommend caution in inferring mortality from injuries, especially when social mobility and emigration out of the study area are common.     

Regulation of natural killer cell activity by macrophages in the rheumatoid joint and peripheral blood

Recently, in another study, we observed that indomethacin, a prostaglandin synthetase inhibitor, significantly increased NK activity in both normal and rheumatoid arthritis (RA) peripheral blood (PB) but not in RA synovial fluid (SF). Because macrophages are a major source of prostaglandins, we examined the effect of macrophage-enriched adherent cells (AC) on NK activity as measured by a 3-hr Cr-release assay with K 562 cells. The removal of AC resulted in increased (p less than 0.01) NK activity in both normal and RA PB. In contrast, the removal of AC from RA SF resulted in a significant decrease (p less than 0.001) of NK activity. By using only nonadherent cells (NAC), NK activity in RA SF and synovial tissue (ST) was significantly reduced when compared to autologous RA PB (p less than 0.001). Enhancement of NK activity of SF NAC by both poly I:C and IL 2 was not dependent on AC. Mixing experiments demonstrated that the addition of synovial AC for 16 hr increased NK activity of synovial NAC to a level similar to that of unseparated mononuclear cells, whereas autologous PB AC suppressed NK activity of PB NAC. PB AC, when added to SF NAC, also increased NK activity. Supernatants from synovial mononuclear cells were stimulatory of synovial NAC NK activity, whereas normal PB mononuclear supernatants were suppressive. These observations document 1) a significant reduction of NAC-mediated NK activity in the rheumatoid joint as compared to PB from the same patient, and 2) that AC modulate NK activity differently in the rheumatoid joint as compared to RA or normal PB.     

Prehistoric sunflower (Helianthus Annuus L.) domestication in Mexico

Early remains of Helianthus annuus L. unearthed at the San Andrés site in the Gulf Coast region of Tabasco, Mexico, constitute the earliest record of domesticated sunflower. Accelerator mass spectrometry (AMS) age determinations of a large domesticated seed and achene produced dates of 4130 ± 40 years before the present (B.P.) and 4085 ± 50 B.P., respectively. These discoveries challenge the longstanding hypothesis that sunflower was domesticated in eastern North America. Moreover, when considered with other recent discoveries on plant domestication, these data suggest a reconsideration of the idea that the eastern United States was an independent hearth for domestication.