Relationships between fecal pellet production and feeding in the calanoid copepod Boeckella

The number, size (mm³ pellet ^–1) and total volume of fecalpellets produced (mm³ h^–1) by Boeckella titicacae increasedwith concentration of Chlorella and natural seston in threedifferent lakewaters from Bahia de Puno and Lago Grande of LakeTiticaca and nearby Laguna Arapa. The three lakewaters differedin the size and number of fecal pellets produced at seston concentrations>0.5 mg dry wt l^–1. However, the total volume of fecalpellets egested varied little. Large-sized food (>10 µg)resulted in larger pellets but smaller total fecal production.Food concentration had parallel effects on the production offeces and on feeding rates. Both fecal production and feedingincreased linearly with food concentration with saturation between5 and 7.5 x 10⁵ Chlorella ml^–1 (3.7–5.6 mg dry wtl^–1). Varied responses in fecal production when fed differentsize fractions of lake seston suggest Boeckella has a complexand flexible feeding behavior. Feeding preferences of B.titicacaeand B.occidentalis (Ivlev index) for two seston size fractionsare generally reflected by fecal production.     

Number of rare germline CNVs and <Emphasis Type="Italic">TP53</Emphasis> mutation types

Background

The Li-Fraumeni syndrome (LFS), an inherited rare cancer predisposition syndrome characterized by a variety of early-onset tumors, is caused by different highly penetrant germline mutations in the TP53 gene; each separate mutation has dissimilar functional and phenotypic effects, which partially clarifies the reported heterogeneity between LFS families. Increases in copy number variation (CNV) have been reported in TP53 mutated individuals, and are also postulated to contribute to LFS phenotypic variability. The Brazilian p.R337H TP53 mutation has particular functional and regulatory properties that differ from most other common LFS TP53 mutations, by conferring a strikingly milder phenotype.

Methods

We compared the CNV profiles of controls, and LFS individuals carrying either p.R337H or DNA binding domain (DBD) TP53 mutations by high resolution array-CGH.

Results

Although we did not find any significant difference in the frequency of CNVs between LFS patients and controls, our data indicated an increased proportion of rare CNVs per genome in patients carrying DBD mutations compared to both controls (p=0.0002***) and p.R337H (0.0156*) mutants.

Conclusions

The larger accumulation of rare CNVs in DBD mutants may contribute to the reported anticipation and severity of the syndrome; likewise the fact that p.R337H individuals do not present the same magnitude of rare CNV accumulation may also explain the maintenance of this mutation at relatively high frequency in some populations.

     

Cryptosporidium canis n. sp. from domestic dogs.

Oocysts of Cryptosporidium, from the feces of a naturally infected dog and from an HIV-infected human, were identified as the previously reported canine genotype of Cryptosporidium parvum, hereafter referred to as Cryptosporidium canis n. sp. Also among the oocysts from the dog, a trace amount of C. parvum bovine genotype was detected. Cryptosporidium canis oocysts from both the dog and human were infectious for calves. Oocysts excreted by calf 1 (dog source) were approximately 90% C. canis and 10% C. parvum, whereas those excreted by calf 3 (human source) were 100% C. canis. Oocysts from calf 1 infected calf 2 resulting in excretion by calf 2 of oocysts approximately 90% C. parvum and 10% C. canis. Oocysts of C. canis were not infectious for BALB/c neonatal mice or immunosuppressed C57 juvenile mice, although all control mice became infected with the C. parvum Beltsville isolate. Oocysts of C. canis from calf 1 and the human were structurally indistinguishable from oocysts of the C. parvum Beltsville isolate (bovine). However, C. canis oocysts differed markedly at the molecular level from all known species of Cryptosporidium based on sequence data for the 18S rDNA and the HSP 70 gene. The differences in genetics and host specificity clearly differentiate C. canis as a new species.     

The Homeodomain Resource: 2003 update

The Homeodomain Resource is a searchable, curated collection of information for the homeodomain protein family. The resource is organized in a compact form and provides user-friendly interfaces for both querying the component databases and assembling customized datasets. The current release (version 5.0, October 2002) contains 1056 full-length homeodomain-containing sequences, 37 experimentally-derived structures, 81 homeodomain interactions, 84 homeodomain DNA-binding sites and 114 homeodomain proteins implicated in human genetic disorders. A new feature of this new release is the inclusion of experimentally-derived protein-protein interaction data for homeodomain family members. All entries are cross-linked for easy retrieval of the original records from source databases. The Homeodomain Resource is freely available through the World Wide Web at http://research.nhgri.nih.gov/homeodomain/.     

Skeletal muscle myopathy caused by Triton WR-1339

After administration (1 g/kg every other day for a total of five injections) of Triton WR-1339, the tonic, anterior (ALD) and phasic, posterior (PLD) latissimus dorsi muscles of the chicken underwent distinct pathological modifications. Some of the morphological alterations in the muscles paralleled those seen after administration of chloroquine, increased autophagic vacuole formation in the ALD muscle and swelling of the sarcoplasmic reticulum in the PLD muscle, but other changes were unique to Triton WR-1339. These included loss of myofilaments and whole myofibrils, indentation of the sarcolemma as well as increased numbers of ribosomes in the ALD muscle and swelling of the T-tubular system in the PLD muscle. These results are compared with other lysosome mediated pathologies, as well as with other myopathies.     

Identification of assemblage A Giardia in white-tailed deer

Fecal samples were collected from hunter-killed white-tailed deer (Odocoileus virginianus) during a managed hunt in a central Maryland county. Fecal samples were cleaned of debris and concentrated by CsCl density gradient centrifugation and stained with MerIFluor reagents. Stained samples were examined by fluorescent microscopy for the presence of Giardia sp. cysts. One of 26 samples was found to be positive for Giardia sp. Polymerase chain reaction amplification using primers directed to the beta-giardin and TPI genes identified the same sample as the only positive one. Sequencing of the beta-giardin and TPI genes revealed that the Giardia sp. belonged to assemblage A, a genotype infectious for humans and also reported in a small percentage of cattle. This is the first report of assemblage A Giardia sp. in deer and suggests that deer could be a potential source of infectious cysts for humans and cattle.     

Surveillance,health promotion and control of Chagas disease in the Amazon Region - Medical attention in the Brazilian Amazon Region: a proposal

We refer to Oswaldo Cruz''s reports dating from 1913 about the necessities of ahealthcare system for the Brazilian Amazon Region and about the journey of CarlosChagas to 27 locations in this region and the measures that would need to be adopted.We discuss the risks of endemicity of Chagas disease in the Amazon Region. Werecommend that epidemiological surveillance of Chagas disease in the Brazilian AmazonRegion and Pan-Amazon region should be implemented through continuous monitoring ofthe human population that lives in the area, their housing, the environment and thepresence of triatomines. The monitoring should be performed with periodicseroepidemiological surveys, semi-annual visits to homes by health agents and thetraining of malaria microscopists and healthcare technicians to identifyTrypanosoma cruzi from patients'' samples and T.cruzi infection rates among the triatomines caught. We recommend healthpromotion and control of Chagas disease through public health policies, especiallythrough sanitary education regarding the risk factors for Chagas disease. Finally, wepropose a healthcare system through base hospitals, intermediate-level units in theareas of the Brazilian Amazon Region and air transportation, considering thedistances to be covered for medical care.     

Effects of age and sex on the induction by triiodothyronine of cortisone delta4-5alpha-reductase and glucose 6-phosphate dehydrogenase of rat liver and adrenal

The effects of age and sex on the induction by 3,5,3′-triiodothyronine (T-3) of cortisone Δ⁴-5α-reductase and glucose 6-phosphate dehydrogenase (G 6-P D) in liver and the latter in adrenal have been investigated. Levels of cortisone Δ⁴-(5α, 5β)-reductase and G 6-P D were measured in homogenates of tissue from normal and T-3 injected male and female rats, $\text{1 1}\text{4}$ to 21 months of age. Increases in the levels of the reductase seen under T-3 stimulation were ascribed to induction of the 5α-reductase alone. T-3 caused induction of cortisone Δ⁴-5α-reductase only in the livers of male rats $\text{1}\text{3}\text{4}$ months of age. There was induction of total G 6-P D at most ages except in the livers of old male and young female rats and adrenals of young and old male rats. At all ages in normal animals of both sexes the maximum activity of glucose 6-phosphate dehydrogenase was much greater than that of cortisone Δ⁴-(5α, 5β)-reductase. It is concluded that the amount of G 6-P D in normal liver may be sufficient to handle an increase in cortisone reduction, and factors other than cortisone Δ⁴-reductase or G 6-P D levels alone must regulate increased reduction of the steroid.