Pneumocystis Antigen Appearance during Immunosuppression

The sequential appearance of Pneumocystis carinii (Pc) antigens during the progression of immunosuppression in rats was studied using the immunobloiting technique and specific immunologic probes. Putative Pc soluble antigens, with molecular weights of approximately 70 and 90 kd. were delected as early as 2 wk after initiation of immunosuppression in rats using a pool of monoclonal antibodies produced to I c isolated from lungs using enzymatic digestion. Monoclonal antibodies produced to Pc isolated by massaging the lung tissue using a Stomacher apparatus and infection-derived sera did not detect soluble antigens until at least the 6th wk of immunosuppression. Analysis of Pc pellets obtained from Stomacher- and lavage-processcd lungs revealed that the lower molecular weight antigens (≤ 40, 45 and possibly 55–60 kd) were recognized early during the immunosuppression process.     

Uptake and Distribution of Copper in Chrysanthemum morifolium

The effects of various levels of copper on the uptake and distributionof copper in Chrysanthemum morifolium grown in solution cultureand peat-sand have been examined. Whole plants growing in shortdays were sampled at regular intervals, divided into roots,stem, leaves and lateral shoots, and analysed for copper. Thepartitioning of copper between these tissues showed that a relativelylarge proportion (30–40 per cent) of the total plant copperwas accumulated in the roots of normal plants during the harvestingperiod, compared with approximately 10 per cent in the rootsof copper deficient plants. Whilst the copper content (ug g^–1) of leaves and stemfrom normal plants was negatively correlated with the amountof dry matter produced (P < 0·001), the correspondingcopper deficient tissues showed little variation in copper contentwith increases in tissue dry weight. A more detailed investigationof the copper content of leaves from normal plants showed thatgradients existed within the plant with respect to both leafposition and time of harvest which could be described by a singlecubic surface equation (P < 0·001).     

Low-resolution structural studies of human Stanniocalcin-1

Background  

Stanniocalcins (STCs) represent small glycoprotein hormones, found in all vertebrates, which have been functionally implicated in Calcium homeostasis. However, recent data from mammalian systems indicated that they may be also involved in embryogenesis, tumorigenesis and in the context of the latter especially in angiogenesis. Human STC1 is a 247 amino acids protein with a predicted molecular mass of 27 kDa, but preliminary data suggested its di- or multimerization. The latter in conjunction with alternative splicing and/or post-translational modification gives rise to forms described as STC₅₀ and "big STC", which molecular weights range from 56 to 135 kDa.     

The histological structure of the calcified lung of the fossil coelacanth Axelrodichthys araripensis (Actinistia: Mawsoniidae)

Abstract: The palaeohistological study of the calcified internal organ of Axelrodichthys araripensis Maisey, 1986, a coelacanthiform from the Lower Cretaceous of Brazil (Crato (Aptian) and Santana (Albian) formations of the Araripe Basin), shows that the walls of this organ consist of osseous blades of variable thickness separated from each other by the matrix. This indicates that, in the living individuals, the walls were reinforced by ossified plates, probably separated by conjunctive tissue. This calcified sheath present in Axelrodichthys, as well as in other fossil coelacanths, lies in ventral position relative to the gut and its single anterior opening is located under the opercle, suggesting a direct connection with the pharynx or the oesophagus. The calcified organ of Axelrodichthys, like that of other fossil coelacanths, is here regarded as an ‘ossified lung’ and compared with the ‘fatty lung’ of the extant coelacanth Latimeria. The reinforcement of the pulmonary walls by the overlying osseous blades could be interpreted as a means of adapting volumetric changes in the manner of bellows, a necessary function for ventilation in pulmonary respiration. Other functional hypotheses such as hydrostatic and/or acoustic functions are also discussed.     

Landscape genetics of an endangered lemur (Propithecus tattersalli) within its entire fragmented range

Habitat fragmentation may strongly reduce individuals’ dispersal among resource patches and hence influence population distribution and persistence. We studied the impact of landscape heterogeneity on the dispersal of the golden‐crowned sifaka (Propithecus tattersalli), an endangered social lemur species living in a restricted and highly fragmented landscape. We combined spatial analysis and population genetics methods to describe population units and identify the environmental factors which best predict the rates and patterns of genetic differentiation within and between populations. We used non‐invasive methods to genotype 230 individuals at 13 microsatellites in all the main forest fragments of its entire distribution area. Our analyses suggest that the Manankolana River and geographical distance are the primary structuring factors, while a national road crossing the region does not seem to impede gene flow. Altogether, our results are in agreement with a limited influence of forest habitat connectivity on gene flow patterns (except for North of the species’ range), suggesting that dispersal is still possible today among most forest patches for this species. Within forest patches, we find that dispersal is mainly among neighbouring social groups, hence confirming previous behavioural observations.     

Arabidopsis thaliana ASN2 encoding asparagine synthetase is involved in the control of nitrogen assimilation and export during vegetative growth

We investigated the function of ASN2, one of the three genes encoding asparagine synthetase (EC 6.3.5.4), which is the most highly expressed in vegetative leaves of Arabidopsis thaliana. Expression of ASN2 and parallel higher asparagine content in darkness suggest that leaf metabolism involves ASN2 for asparagine synthesis. In asn2‐1 knockout and asn2‐2 knockdown lines, ASN2 disruption caused a defective growth phenotype and ammonium accumulation. The asn2 mutant leaves displayed a depleted asparagine and an accumulation of alanine, GABA, pyruvate and fumarate, indicating an alanine formation from pyruvate through the GABA shunt to consume excess ammonium in the absence of asparagine synthesis. By contrast, asparagine did not contribute to photorespiratory nitrogen recycle as photosynthetic net CO₂ assimilation was not significantly different between lines under both 21 and 2% O₂. ASN2 was found in phloem companion cells by in situ hybridization and immunolocalization. Moreover, lack of asparagine in asn2 phloem sap and lowered ¹⁵N flux to sinks, accompanied by the delayed yellowing (senescence) of asn2 leaves, in the absence of asparagine support a specific role of asparagine in phloem loading and nitrogen reallocation. We conclude that ASN2 is essential for nitrogen assimilation, distribution and remobilization (via the phloem) within the plant.     

Y chromosome microsatellite markers identified from the tammar wallaby (Macropus eugenii) and their amplification in three other macropod species

Microsatellites were identified from three fully sequenced Y chromosome‐specific bacterial artificial chromosome clones from the tammar wallaby, Macropus eugenii. Ten microsatellites were genotyped in male tammar wallabies. Four loci were polymorphic with between two and six alleles per locus. Eleven different haplotypes were identified from 22 male tammar wallabies. No amplifications were obtained from female samples. Each microsatellite was also shown to amplify reliably in at least one other macropod species. These markers may therefore prove useful as some of the first male‐specific genetic markers for marsupials, with potential application to studies of male‐biased dispersal and mating systems.     

Development and characterization of microsatellite loci in Mormon crickets (Anabrus simplex,Orthoptera, Tettigoniidae)

Anabrus simplex is an economically significant crop pest in the western United States and is a model organism for studying the influence of sex role reversal on sperm allocation and utilization patterns and population genetics. We isolated seven polymorphic microsatellite loci in Anabrus simplex, and within population allele numbers ranged from 10 to 25. High polymorphism is not unusual for Orthopteran insects, although observed heterozygosities ranged from 0.24 to 0.91 and were lower than expected heterozygosities, suggesting null alleles. These microsatellites will greatly facilitate studies of postcopulatory reproductive isolation in nuptial gift‐giving insects and historical phylogenetics in the Rocky Mountains.     

Tetratricopeptide Repeat Domain 9A Negatively Regulates Estrogen Receptor Alpha Activity

Tetratricopeptide repeat domain 9A (TTC9A) is a target gene of estrogen and progesterone. It is over-expressed in breast cancer. However, little is known about the physiological function of TTC9A. The objectives of this study were to establish a Ttc9a knockout mouse model and to study the consequence of Ttc9a gene inactivation. The Ttc9a targeting vector was generated by replacing the Ttc9a exon 1 with a neomycin cassette. The mice homozygous for Ttc9a exon 1 deletion appear to grow normally and are fertile. However, further characterization of the female mice revealed that Ttc9a deficiency is associated with greater body weight, bigger thymus and better mammary development in post-pubertal mice. Furthermore, Ttc9a deficient mammary gland was more responsive to estrogen treatment with greater mammary ductal lengthening, ductal branching and estrogen target gene induction. Since Ttc9a is induced by estrogen in estrogen target tissues, these results suggest that Ttc9a is a negative regulator of estrogen function through a negative feedback mechanism. This is supported by in vitro evidence that TTC9A over-expression attenuated ERα activity in MCF-7 cells. Although TTC9A does not bind to ERα or its chaperone protein Hsp90 directly, TTC9A strongly interacts with FKBP38 and FKBP51, both of which interact with ERα and Hsp90 and modulate ERα activity. It is plausible therefore that TTC9A negatively regulates ERα activity through interacting with co-chaperone proteins such as FKBP38 and FKBP51.     

1H NMR metabolomics reveals increased glutaminolysis upon overexpression of NSD3s or Pdp3 in Saccharomyces cerevisiae

NSD3s, the proline-tryptophan-tryptophan-proline (PWWP) domain-containing, short isoform of the human oncoprotein NSD3, displays high transforming properties. Overexpression of human NSD3s or the yeast protein Pdp3 in Saccharomyces cerevisiae induces similar metabolic changes, including increased growth rate and sensitivity to oxidative stress, accompanied by decreased oxygen consumption. Here, we set out to elucidate the biochemical pathways leading to the observed metabolic phenotype by analyzing the alterations in yeast metabolome in response to NSD3s or Pdp3 overexpression using ¹H nuclear magnetic resonance (NMR) metabolomics. We observed an increase in aspartate and alanine, together with a decrease in arginine levels, on overexpression of NSD3s or Pdp3, suggesting an increase in the rate of glutaminolysis. In addition, certain metabolites, including glutamate, valine, and phosphocholine were either NSD3s or Pdp3 specific, indicating that additional metabolic pathways are adapted in a protein-dependent manner. The observation that certain metabolic pathways are differentially regulated by NSD3s and Pdp3 suggests that, despite the structural similarity between their PWWP domains, the two proteins act by unique mechanisms and may recruit different downstream signaling complexes. This study establishes for the first time a functional link between the human oncoprotein NSD3s and cancer metabolic reprogramming.