A split-pot experiment with sorghum to test a root water uptake partitioning model

Correct modeling of root water uptake partitioning over depth is an important issue in hydrological and crop growth models. Recently a physically based model to describe root water uptake was developed at single root scale and upscaled to the root system scale considering a homogeneous distribution of roots per soil layer. Root water uptake partitioning is calculated over soil layers or compartments as a function of respective soil hydraulic conditions, specifically the soil matric flux potential, root characteristics and a root system efficiency factor to compensate for within-layer root system heterogeneities. The performance of this model was tested in an experiment performed in two-compartment split-pot lysimeters with sorghum plants. The compartments were submitted to different irrigation cycles resulting in contrasting water contents over time. The root system efficiency factor was determined to be about 0.05. Release of water from roots to soil was predicted and observed on several occasions during the experiment; however, model predictions suggested root water release to occur more often and at a higher rate than observed. This may be due to not considering internal root system resistances, thus overestimating the ease with which roots can act as conductors of water. Excluding these erroneous predictions from the dataset, statistical indices show model performance to be of good quality.     

Morphological and histological study of castration-induced degeneration and androgen-induced regeneration in the mouse prostate

Degenerative and regenerative changes in the ductal architecture of the ventral and dorsolateral prostates (VP and DLP) of the adult mouse were investigated in microdissected specimens over a time-course of 14 days following castration and subsequently during 14 days of administration of testosterone propionate. After castration, about 35% of the ductal tips and branch-points were lost in distal regions (usually near the capsule) in both prostatic lobes. By contrast, in more proximal regions of the prostate (closer to the urethra), the ducts survived in an atrophic condition. The ductal morphology that had been lost in the distal regions completely regenerated after testosterone propionate was administered to the castrated males. In the VP, androgen replacement simply returned the gland to its former size with moderate ductal distension; in the DLP, excessive epithelial infoldings and ductal distension were elicited in the distal regions of the ducts after 14 days of treatment with testosterone propionate. These results suggest that androgenic responsiveness and dependency are different in distal versus proximal ducts. Distal ducts are exquisitely androgen-dependent and androgen-sensitive; in proximal regions, androgen-dependency is not as strict.     

Salmonella serotypes isolated from human enteric processes in Recife, Pernambuco, during 1978-1980

From 13,196 faecal cultures made in Recife-Pernambuco during the period from 1978 to 1980, 1,720 strains of Salmonella were isolated. Serological typing on 1,387 of the isolates recognized 63 serotypes, 73.18% of which belonged to group B. The prevalent serotypes adding up to 1,231 strains (88.75% of the total of the isolates) were: S. typhimurium, S. saint-paul, S. poona, S. derby, S. agona, S. newport, S. oranienburg, S. infantis, S. tshiongwe and S. ndolo.     

Tumor promoter chloroform is a potent protein kinase C activator

The major interaction site for tumor-promoting phorbol esters is the calcium-activated, phospholipid-dependent protein kinase (protein kinase C), a key-element in signal transduction. Binding of phorbol esters results in enzyme activation which mediates, at least in part, the action of these agents. We have investigated the effects of tumor promoter chloroform on protein kinase C activity. Like thrombin and 12-O-tetradecanoylphorbol-13-acetate (TPA), chloroform was able to activate protein kinase C in intact rabbit platelets. In addition, chloroform stimulated enzyme activity as well as TPA binding capacity in cell-free system. Scatchard analysis of the data has shown that chloroform increased the number of phorbol ester binding sites. Structurally related compounds, carbon tetrachloride and methylene chloride, activated the enzyme similarly.     

Prevalence of nits and lice in samples of cut hair from floors of barbershops and beauty parlors in Belo Horizonte, Minas Gerais State, Brazil

A louse survey based on samples of cut hair collected from floors of barbershops and beauty parlors was conducted in Belo Horizonte, Minas Gerais State, Brazil, from October 1984 to April 1985, as an alternative way to determine the prevalence of pediculosis capitis in the population. Of 475 samples examined for nits, nymphs, or adults of Pediculus capitis, 140 were infested (29.5%). A total of 58 lice and 3,553 nits were found in 33,632.9 g of hair collected, giving a ratio of 0.10 nit/g. Almost 29% of the nits were viable and capable of being transmitted after hatching. There was significant difference among the infestation rates by socioeconomic levels, and samples from barbershops with male customers were the most infested. Based upon the number of haircuts in each sample, we estimated that 5 or 6% of the population might be infested by this species.     

Biology of Triatoma vitticeps (Stal, 1859) under laboratory conditions (Hemiptera: Reduviidae: Triatominae). I. Evolutive cycle

Observations were made on the evolutive cycle of Triatoma vitticeps, held under laboratory conditions and fed weekly in mice. Of the 435 eggs obtained, from 4 virgin couples, 149 were purposed for the biological cycle study and 286 to evaluate their resistance to starvation, which shall be a second part of this work. Only 50 specimens reached the adult stage in a period of means (S) = 270 +/- 45 days. At the incubation time, the first and second instars were of less than a month for each, while the third, fourth and fifth instars requires approximately one, two and three months, respectively. The search for the first meal occurred clearly on the 3rd, 6th and 10th day. During all the stages, more than 50% of the specimens had only one blood-meal, except the fifth one, when two blood-meals were required. In relation to the time-lapse between the presenting of the blood-meal and the beginning of feeding, as well as the length of the blood-meal, it was observed that these increased gradually according to the stage. From the 423 blood-meals performed, 390 were not followed by defecation in the settled period of 10 min. Under this point of view, T. vitticeps seems to be a poor transmissor of T. cruzi. The experiment was carried out for 13 months and by this time the averages of minimum and maximum temperatures and the humidity were 25 +/- 2 degrees C - 28 +/- 2 degrees C and 80 +/- 2%, respectively. The material belongs to the triatomine colony held at the Oswaldo Cruz Institute, Department of Entomology.