A further 46,XYp- female

A 24-year-old female with a Swyer syndrome phenotype was found to have a 46,X,del (Y) (p11) karyotype. This observation is consistent with the recently confirmed assignment of the testis-determining master gene to the deletion interval 1A of the Y (Page et al., 1987). Otherwise, it illustrates the etiological heterogeneity of the Swyer phenotype and allows to emphasize the de novo origin of XYp-females.     

Isolation of fecal coliforms from pristine sites in a tropical rain forest.

Samples collected from water accumulated in leaf axilae of bromeliads (epiphytic flora) in a tropical rain forest were found to harbor fecal coliforms. Random identification of fecal coliform-positive isolates demonstrated the presence of Escherichia coli. This bacterium was also isolated from bromeliad leaf surfaces. These data indicate that E. coli may be part of the phyllosphere microflora and not simply a transient bacterium of this habitat. The isolation of fecal coliforms from these sites was unexpected and raises questions as to the validity of using fecal coliforms as indicators of biological water quality in the tropics.     

Familial inv(2) (p2300q11.2)

A hitherto undescribed inv(2) (p2300q11.2) was found in 2 generations of a family ascertained through a holoprosencephalic liveborn boy with normal karyotype. This inversion, quite probably not related to the child malformations, does not seem neither impair reproductive fitness nor to yield viable recombination aneusomies.     

Nutrients and mass in litter and top soil of ten tropical tree plantations

The importance of litter to nutrient and organic matter storage and the possible influence of species selection on soil fertility in ten stands each consisting of a separate tree species were examined in this study. The plantations had been grown under similar conditions in an arboretum in the Luquillo Experimental Forest, Puerto Rico. The species involved were: Anthocephalus chinensis, Eucalyptus × patentinervis, E. saligna, Hernandia sonora, Hibiscus elatus, Khaya nyasica, Pinus caribaea var. hondurensis, P. elliottii var. densa, Swietenia macrophylla, and Terminalia ivorensis. After 26 yr, litter mass ranged from 5 mg ha^-1 in the H. sonora stand to 27.2 Mg ha^-1 in the P. caribaea stand. Nutrients in the litter (N, P, K, Ca, and Mg) also varied widely, but stands were ranked in different order when ranked by nutrients in the litter than then ranked according to accumulation of mass. Only E. saligna and A. chinensis stands were ranked similarly in accumulation of both nutrients and mass, and the stand of H. elatus was ranked higher with respect to nutrient accumulation than to accumulation of mass. The nutrient concentration in standing leaf litter generally increased in the order of recently fallen <old intact< fragmented. Nutrient concentration of standing leaf litter appears to increase with age and depth in the litter layer. The amount of nutrients stored in the litter compartment of these plantations was in the same order of magnitude as the quantity of available nutrients in the top 10-cm of mineral soil. Total litter mass was negatively correlated with the mass-weighted concentration of N, K, and Mg. The same relationship was found for Ca in the leaf litter and N in the fine wood litter compartments. In some stands (notably P. caribaea, P. elliottii, and E. saligna), leaf litter derived from species other than the species planted in that particular stand had higher nutrient concentration than leaf litter from the planted species. Soils of the 10 stands were classified in the same soil series and had similar texture (clay soils). However, significantly different chemical characteristics were found. Results obtained by analysis of covariance and by limiting comparisons to adjacent stands with similar soil texture, indicate that different species have had different influences on the concentration of available nutrients in soil.     

C-anaphases: a mitotic variant.

In order to assess the frequency of C-anaphases in colchicine-arrested lymphocyte cultures, the authors studied 100 patients classified in four groups: spontaneous abortion (n = 17), subfertility (n = 12), aneuploidy (n = 18) and miscellaneous (n = 53). At least 300 mitotic G-banded cells were scored by individual. In 12 individuals no C-anaphases were observed; in 87 individuals the range was 1-7 with a mode of 2 and a mean of 2.14; the remaining individual had 19 C-anaphases in 330 cells (5.7%). The statistical analysis did not show significant differences between the groups (p > 0.05). These data along with previous studies indicate that normally most individuals have < or = 3% of C-anaphases in habitual lymphocyte cultures. Moreover, there exists an autosomal dominant form in which individuals with the trait have > 5% of the cells with such mitotic configurations. We conclude that both the low frequency common and the high frequency familiar forms are mitotic variants without pathological significance.     

Detection of virulence factors in culturable Escherichia coli isolates from water samples by DNA probes and recovery of toxin-bearing strains in minimal o-nitrophenol-beta-D-galactopyranoside-4-methylumbelliferyl-beta-D-g luc uronide media.

A total of 449 Escherichia coli isolates in treated and raw water sources were submitted to DNA-DNA hybridization using seven different DNA probes to detect homology to sequences that code for Shiga-like toxins I and II; heat-stabile and heat-labile toxins, adherence factors EAF and eae, and the fimbrial antigen of entero-hemorrhagic E. coli. Fifty-nine (13%) of the isolates demonstrated homology with one or more specific DNA probes. More than 50% of the isolates in treated water were not recovered in MMO-4-methylumbelliferyl-beta-D-glucuronide media designed for detection of this indicator.     

Candida biotypes in patients with oral leukoplakia and lichen planus

Prevalence of yeasts in 35 leukoplakia and 34 oral lichen planus patients was compared with that observed in persons without oral diseases. Serotype and morphotype were determined on Candida albicans isolates. Yeasts were isolated from the oral cavity specimens of 43.7% of the patients. C. albicans (serotype A) was the predominant species (76% in leukoplakia, 88.2% in lichen planus and 60.8% in healthy persons). Sixteen morphotypes were encountered on malt extract agar, being 732, 733, 734, 753 and 754 the most frequently found. Morphotypes SP1N and SP1Y were the most common on Sabouraud-trypheniltetrazolium agar (68.4% of the isolates from leukoplakia and 73.3% from lichen planus, but only 46.6% of the isolates from healthy oral mucosa showed SP1N morphotype). Presence of oral lesions was associated with a marked reduction in the yeast species and C. albicans biotypes, suggesting that C. albicans and particularly some of its biotypes, show a high potential of adaptation to the changes associated with the development of oral leukoplakia and lichen planus.     

A structural and evolutionary analysis of a dispersed repetitive sequence

A family of dispersed repetitive sequences (Hch1) which is present in the genome of the wild barley Hordeum chilense was studied in detail. Hch1 sequences are found both as part of short tandem arrays and dispersed throughout the H. chilense chromosomes. Subcloning of sections of the sequence reveals that it is composed of unrelated classes of sequences which can also be found separately in other genomic locations. Analysis of these sequences in the genomes of wheat and two other wild barley species strongly suggests that specific amplifications and arrangements of the repeated sequences have taken place during speciation. Nucleotide sequence analysis fails to detect, in their entirity, the features shown by plant transposons.