Diverse endophytic bacteria isolated from a leguminous tree Conzattia multiflora grown in Mexico

Conzattia multiflora is a leguminous tree present only in Mexico and Guatemala. There is no record about its symbiotic or pathogenic microbes. In this study, we found that numerous bacteria with 10⁴–10⁶ individuals per gram of fresh epidermis were distributed in the tissue of this plant. All the bacteria isolated from the Conzattia epidermis were Gram-negative, facultative anaerobic rods and formed yellow or colorless colonies. They were identified as endophytes by inoculation tests. Some of the bacteria could significantly promote the growth of Conzattia seedlings. Nine different groups were defined by PCR-based RFLP, which were classified as Pantoea, Erwinia, Salmonella, Enterobacter, Citrobacter and Klebsiella by the phylogenetic analysis of 16S rRNA genes. The existence of plant-borne lineages of Salmonella indicates that the unexplored plants may harbor some unknown microbes.     

Multiple sexual ornaments signal heterozygosity in male blue tits

Higher individual genetic quality has been hypothesized to be associated with the expression of conspicuous ornaments. However, the relationship between multicomponent sexual signals and heterozygosity is poorly understood. In this study, we examined whether different ornaments, including song (repertoire size and bout length) and plumage coloration (yellow breast and blue crown), reflect individual genetic diversity in male blue tits (Aves: Cyanistes caeruleus). We estimated genetic diversity using 26 microsatellite markers that were classified as putatively functional (12 loci) and neutral (14 loci). We found that yellow breast carotenoid chroma, blue crown brightness, bout length and body condition were positively associated with heterozygosity at functional loci, but not with genetic diversity estimated at all typed loci or the subset of neutral markers. The lack of strong single‐locus effects and the presence of identity disequilibrium in our population suggest that the observed heterozygosity‐phenotype associations are driven by loci widely distributed across the genome. The predominant role of putatively functional loci evidences that the expression of secondary sexual characters is more tightly reflected by heterozygosity at genomic regions containing coding genes that are being actively expressed, a fact that may make ornamental traits more reliable indicators of the genetic quality of individuals. Overall, this study shows that multiple secondary sexual characters reflect male genetic diversity and lends support to the good‐genes‐as‐heterozygosity hypothesis. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 115 , 362–375.     

Uterine phenotype of young adult rats exposed to dietary soy or genistein during development

Dietary soy intake is associated with protection from breast cancer, but questions persist on the potential risks of the major soy isoflavone genistein (GEN) on female reproductive health. Here, we evaluated intermediate markers of cancer risk in uteri of cycling, young adult Sprague-Dawley rats lifetime exposed to one of three AIN-93G semipurified diets: casein (CAS), soy protein isolate (SPI+ with 276 mg GEN aglycone equivalents/kg) and CAS+GEN (GEN at 250 mg/kg). Postnatal day 50 (PND50) rats lifetime exposed to GEN or SPI+ had similar uterine luminal epithelium height, myometrial thickness, endometrial gland numbers, endometrial immunoreactive proliferating cell nuclear antigen (PCNA), and serum estrogen and progesterone, as CAS-fed rats. GEN-fed rats showed modestly increased apoptosis in uterine glandular epithelium, compared to those of CAS- or SPI+-fed groups. Diet had no effect on the uterine expression of genes for the tumor suppressors PTEN, p53 and p21, and the apoptotic-associated proteins Bcl2, Bax and progesterone receptor. Uterine tissue and serum concentrations of total GEN were higher in rats fed GEN than in those fed SPI+. Human Ishikawa endocarcinoma cells treated with GEN-fed rat serum tended to exhibit increased apoptotic status than those treated with CAS-fed rat serum. Exogenously added GEN (0.2 and 2 microM) increased, while estradiol-17beta (0.1 microM) decreased Ishikawa cell apoptosis, relative to untreated cells. Results suggest that lifetime dietary exposure to soy foods does not alter uterine cell phenotype in young adult rats, while GEN, by enhancing uterine endometrial glandular apoptosis in vivo and in vitro, may confer protection against uterine carcinoma. Given its limited influence on uterine phenotype of young adult females, GEN, when taken as part of soy foods or as supplement, should be favorably considered for other potential health benefits.     

Interference between Neisseria meningitidis and PC-KLH Induced Anti-Phosphorylcholine PFC Responses in NZB/W Autoimmune Mice

In this work, we demonstrate that the simultaneous injection of PC-KLH and Neisseria meningitidis-derived antigens [NMB or PC-(NMB)HI] induced in old NZB/W mice defective responses as does PC-KLH challenge. On the other hand, the simultaneous injection of both immunogenic preparations of N. meningitidis evoked responses similar to those shown by old mice challenged with NMB alone. Alteration in PC-specific PFC responses also affected hapten-free inhibition profiles and their heterogeneities. The increase in PC₅₀s of anti-phosphorylcholine PFC responses and their heterogeneities induced by certain antigens with aging is correlated with a decrease in T15 idiotype expression, suggesting that after the T15 dominant clone disappears no other clone takes control of the anti-PC response. These results suggest that the mechanism(s) involved in the regulation of T15 marker expression play an important role in the inability of old NZB/W mice to mount good anti-PC responses and suggest that regulatory mechanisms induced by PC-KLH dominate those elicited by NMB.     

Human prepubertal testicular cells in culture: Steroidogenic capacity, paracrine and hormone control

The neonatal human Leydig cell undergoes a transient period of activation during the first months of life. The biological significance of this activation is unknown. Furthermore, little is known about the hormonal regulation of this biological process, even though it coincides with an elevation of LH levels in serum. In order to study the function of human prepubertal testicular culture cells, obtained during the neonatal period, a method for maintaining primary culture cells (isolated from testes collected at necropsy) in culture was developed. Within 24 h after death, testes were collected from 1–36-month-old subjects. Subjects were divided into two age groups, based on the presence or absence of fetal Leydig cells: 1–7-month-old infants (group 1) and 12–36-month-old children (group 2). Testes were digested with collagenase, and cells were seeded in multi-well dishes. Cells were grown in serum-free conditioned media supplemented with 5 mg/l vitamin C, 0.2 IU/l vitamin E and 10% fetal bovine serum for 2 days. Cells were then grown for an additional 4 days in serum-free media in the presence or absence of hLH (40 IU/l), hCG (135 IU/l), rh FSH (1.5 IU/l), rhGH (0.12 IU/l) or insulin (0.9 μmol/l). Concentrations of steroids in media were determined by RIA on day 6 of culture. In basal conditions cells of group 1 (n = 11) secreted more testosterone, androstendione, 17-hydroxyprogesterone, progesterone and dehydroepiandrosterone (mean ± SE: 6.76 ± 1.86, 7.37 ± 1.82, 61.9 ± 1.86, 5.75 ± 1.74 and 8.51 ± 3.23 pmol/10⁶ cells/24 h, respectively) than cells of group 2 (n = 5) (2.95 ± 1.15, 1.50 ± 2.75, 1.44 ± 2.75, 0.78 ± 1.74 and 3.23 ± 1.32, respectively). Under hLH stimulation, cells of group 1 increased testosterone, androstendione and 17-hydroxyprogesterone secretions (to 38.2 ± 0.89, 13.5 ± 1.17 and 51.7 ± 3.23), while progesterone secretion remained unchanged (2.82 ± 1.20). Cell response to rhFSH and rhGH was similar to that of hLH. On the other hand, medium collected from cultures of cells isolated from a Sertoli cell tumor was able to stimulate testosterone secretion in subcultures of control testicular cells in a way similar to that of hCG. In conclusion, (1) these prepubertal human testicular cells can be maintained in primary culture for several days keeping their in vivo steroidogenic potential; (2) cells isolated from young infants can respond to hLH in culture; (3) response to rhFSH is probably mediated by a paracrine factor; (4) response to rhGH is observed in the absence of gonadotropins. Therefore, the early postnatal activation of the human testis might be under multiple pituitary hormone control; and, finally, (5) Sertoli cell tumors can secrete paracrine factors that stimulate steroidogenesis.     

Time-periodic oscillations in a model for the respiratory process of a bacterial culture

Summary Deterministic (analytical), stochastic and computer-aided methods have been used to construct the time-periodic (limit cycle) solution of a model suggested by H. Degn to account for the qualitative features of the respiratory process in a Klebsiella Aerogenes bacterial culture.     

Comparative study on Salmonella isolation from sewage—contaminated natural waters

A lcaide , E., M artinez , J.P. & G aray , E. 1984. Comparative study on Salmonella isolation from sewage contaminated natural waters. Journal of Applied Bacteriology 56 , 365–371.
A comparative study of five factors influencing the isolation of salmonellas from sewage-contaminated natural waters was carried out. The effect of pre-enrichment in buffered peptone water was compared with single-step enrichment in NR10 broth incubated at 43C. A modification of NR10 has been compared with the original composition. Bismuth sulphite agar (BSA), Hektoen enteric agar (HE) and brilliant green agar (BGA) have been used as plating media. Other factors considered have been temperature of the water and sampling site. A total of 759 salmonella strains belonging to 36 different serotypes has been recovered in a two-year study. All five factors considered in the study have shown a significant effect on the recovery of salmonellas. The combination of direct enrichment in NR10, followed by BSA or HE as plating media was most effective for the isolation of Salmonella . The influence of water temperature and characteristics of the sampling sites have also been discussed.     

Identification of small nuclear DNA molecules of the cuban sugarcane cultivar Ja60-5 via pulsed field gel electrophoresis

We present evidence of the existence of at least 7 small nuclear DNA molecules in the Ja60-5 sugarcane cultivar genome. These small molecules were separated by means of transversal alternating field electrophoresis (TAFE); their sizes ranged from about 230–3000 kbp, and they hybridized with telomeric, subcentromeric, and various nuclear DNA probes. Here, we also report the use and the modifications of DNA from microorganisms, to immobilize nuclear DNA from sugarcane suitable for analysis via pulsed field gel electrophoresis. The protocol is simple, inexpensive, and easy to perform.