Historical dimensions of population structure in a continuously distributed marine species: The case of the endemic Chilean dolphin

The complementarity of historical and contemporary processes contributes to understanding the genetic structure of continuously distributed marine species with high dispersal capabilities. Cephalorhynchus eutropia, has a continuous coastal distribution with strong genetic differentiation identified by nuclear DNA markers. We explored the historical dimension of this genetic differentiation between northern and southern populations to evaluate phylogeographic structure. Additionally, we conducted mtDNA and microsatellite analyses to detect past and recent demographic changes. The southern population was characterized by lower genetic diversity with a signal of population expansion, likely associated with ice retreat and habitat extension after the Last Glacial Maximum (LGM). In contrast, structure within the northern population was more consistent with stable historical population size. Approximate Bayesian Computation analyses suggested that during the LGM, C. eutropia persisted in the northern area; while the south was colonized by dispersal ~11,000 years ago followed by population expansion. This study shows that Chilean dolphin population structure is consistent with predictions from the Expansion-Contraction biogeographic model, with a poleward post-glacial shift revealed in current genetic structure. The results also confirm the validity of the population units previously identified, demonstrating their historical origin and highlighting the utility of integrating genetic markers with different temporal scale resolutions.

Biodegradation of roxarsone by a bacterial community of underground water and its toxic impact

Roxarsone is included in chicken food as anticoccidial and mainly excreted unchanged in faeces. Microorganisms biotransform roxarsone into toxic compounds that leach and contaminate underground waters used for human consumption. This study evaluated roxarsone biotransformation by underground water microorganisms and the toxicity of the resulting compounds. Underground water from an agricultural field was used to prepare microcosms, containing 0.05 mM roxarsone, and cultured under aerobic or anaerobic conditions. Bacterial communities of microcosms were characterized by PCR-DGGE. Roxarsone degradation was measured by HPLC/HG/AAS. Toxicity was evaluated using HUVEC cells and the Toxi-ChromoTest kit. Roxarsone degradation analysis, after 15 days, showed that microcosms of underground water with nutrients degraded 90 and 83.3% of roxarsone under anaerobic and aerobic conditions, respectively. Microcosms without nutrients degraded 50 and 33.1% under anaerobic and aerobic conditions, respectively. Microcosms including nutrients showed more roxarsone conversion into toxic inorganic arsenic species. DGGE analyses showed the presence of Proteobacteria, Firmicutes, Actinobacteria, Planctomycetes and Spirochaetes. Toxicity assays showed that roxarsone biotransformation by underground water microorganisms in all microcosms generated degradation products toxic for eukaryotic and prokaryotic cells. Furthermore, toxicity increased when roxarsone leached though a soil column and was further transformed by the bacterial community present in underground water. Therefore, using underground water from areas where roxarsone containing manure is used as fertilizer might be a health risk.

Comparison between two cord blood collection strategies

BACKGROUND AND OBJECTIVES

Collection strategy is the first step for collecting good quality cord blood (CB) units. There are two principal different techniques to collect CB from the umbilical vein: in the delivery room while the placenta is still in the uterus by midwives and obstetricians or in an adjacent room after placental delivery by CB-bank trained personnel. In this study, the benefits and disadvantages between two different CB collection strategies were evaluated in order to improve CB bank methodology.

DESIGN AND METHODS

Valencia CB bank maintains the two different collection strategies aforementioned. Before processing CB units, volume was calculated and samples were drawn for cell counts. After processing and before cryopreservation, samples for cell counts, CD34 analysis, viability, clonogenic assays and microbiology were drawn directly from the bags. We compared the efficiency of the two collection techniques.

RESULTS

Obstetric date and umbilical CB was obtained from 848 vaginal (484 collected in uterus and 364 collected ex uterus). The proportion of excluded CB units before processing was 33% for ex uterus and 25% for in uterus. The difference was statistically significant. A larger volume and a higher number of total nucleated cells, CD34+ cells and CFUs were harvested in the in uterus collection group.

INTERPRETATION AND CONCLUSIONS

Based on our findings, we conclude that the mode of collection influences the hematopoietic content of CB donations. Collection before placental delivery is the best approach to CB collection and allows optimizing CB bank methodology.

Comparison between two strategies for umbilical cord blood collection

The use of cord blood (CB) for transplantation has increased greatly in recent years. The collection strategy is the first step in collecting good-quality CB units. There are two main techniques for collecting CB from the umbilical vein: in the delivery room while the placenta is still in the uterus by midwives and obstetricians or in an adjacent room after placental delivery by CB bank trained personnel. In this study, the benefits and disadvantages between the two different CB collection strategies were evaluated, in order to improve CB bank methodology. Valencia CB bank maintains the two different collection strategies. CB was obtained from 569 vaginal and 70 caesarean deliveries and obstetrical and clinical charts were reviewed. Before processing CB units, volume was calculated and samples were drawn for cell counts. After processing and before cryopreservation samples were drawn for cell counts, CD34+cell analysis, viability, clonogenic assays and microbiology were drawn directly from the bags. We compared the efficiency of the two collection techniques. Obstetric data and umbilical CB were obtained from 569 vaginal (264 collected in utero and 305 collected ex utero) and 70 caesarean deliveries. The proportion of excluded CB units before processing was 33% for vaginal ex utero, 25% for vaginal in utero and 46% for caesarean deliveries. Differences were statistically significant. For vaginal deliveries a larger volume and a higher number of nucleated cells, percentage of CD34+ cells and colony-forming units (CFUs) were harvested in the in utero collection group. There was no statistical difference between CB collected after placental expulsion from vaginal and caesarean deliveries. Comparison between all vaginal and caesarean deliveries did not show any difference. We conclude that the mode of collection influences the haematopoietic content of CB donations. Collection before placental delivery is the best approach to CB collection and allows optimisation of CB bank methodology. Caesarean deliveries seem to contain similar progenitor content to vaginal deliveries.

Chromate reduction in Serratia marcescens isolated from tannery effluent and potential application for bioremediation of chromate pollution

Pollution of aquatic systems by heavy metals has resulted in increasing environmental concern because they cannot be biodegraded. One metal that gives reason for concern due to its toxicity is chromium. Cr(VI) and Cr(III) are the principal forms of chromium found in natural waters. A chromate-resistant strain of the bacterium S. marcescens was isolated from tannery effluent. The strain was able to reduce Cr(VI) to Cr(III), and about 80% of chromate was removed from the medium. The reduction seems to occur on the cell surface. Transmission electron microscopic examination of cells revealed that particles were deposited on the outside of bacterial cells. A stable biofilm was formed in less than 10 h, reaching around 1010 cfu attached per milligram of activated carbon. These findings demonstrate that immobilized S. marcescens might be used in industrial waste treatment processes.

Psychosocial and traditional risk factors in early ischaemic heart disease: cross-sectional correlates

BACKGROUND

Psychosocial/emotional distress has been repeatedly found to be a correlate of the onset/aggravation of ischaemic heart disease.

METHODS

Eighty-three patients (63 men and 20 women) with known coronary artery disease who entered an aggressive lifestyle modification programme were administered a clinical/demographic history and the Symptom Checklist 90--Revised at baseline. Several measures of social isolation/alienation (shyness/self-consciousness, feeling lonely, feeling abused and overall) were derived from the the Symptom Checklist 90--Revised.

RESULTS

Univariate tests of the association of known cardiovascular risk factors and the Symptom Checklist 90--Revised scales with age at initial diagnosis yielded several significant results for history of hypercholesterolaemia (P = 0.018), history of hypertension (P = 0.030), somatization (P = 0.007), obsessive-compulsive (P = 0.009), depression (P = 0.006), anxiety (P = 0.021), hostility (P = 0.003), paranoia (P = 0.050), psychoticism (P = 0.029), the Global Severity Index (P = 0.007), the Positive Symptom Distress Index (P = 0.005), the Positive Symptom Total Score (P = 0.003) and feeling abused (P = 0.037). Only history of hypertension, history of hypercholesterolaemia and the hostility scale (overall F = 6.08 and P = 0.0009) emerged as unique correlates of age at initial diagnosis in a multiple regression using only the significant univariate predictors.

CONCLUSIONS

Psychosocial factors are sufficiently confounded with one another that they lose their predictive value once one is entered in the equation. High scores on the hostility scale were associated with a 5.7 year differential in age at initial diagnosis. The younger a patient is at initial diagnosis, the more likely he/she is to have high levels of emotional distress.