Androgen receptors in ventral prostate glands of zinc deficient rats

Androgen binding has been studied in the prostate cytosol of zinc deficient rats by charcoal assays. Rats were housed individually in plastic cages and maintained on a zinc deficient diet for 3 months. The cytosol fraction of prostate gland was incubated with various concentrations of tritiated methyltrienolone (3H-R1881, a synthetic androgen) alone or in the presence of 500-fold excess of radioinert R1881. Scatchard analysis of the data revealed that the number of androgen binding sites in the cytosol fraction of the zinc deficient rat prostate was 31 +/- 5.2 fmol/mg cytosol protein. This was significantly lower than that (84 +/- 11.5 fmol/mg protein) of the controls. Their dissociation constant (Kd = 1.6 +/- 0.6 nM) on the other hand was not different from that (1.7 +/- 0.7 nM) of control animals. This decrease in the concentration of cytosol receptor sites in the zinc deficient state suggests that this metal is involved in the androgen-binding process in the target cells.     

CORTICOTROPHIN INCREASES CEREBRAL POLYAMINE CONTENT

Abstract— To determine whether changes in cerebral polyamines might mediate previously reported ACTH-induced changes in brain biochemistry and behavior, the cerebral content of polyamines was examined following ACTH treatment. Male CD-1 mice were injected daily for 3 days with long-acting (zinc phosphate) preparations of ACTH_1–24 (1 μg/g) or ACTH_4–10 (0.33 μg/g) and killed 24 h after the last injection. Putrescine, spermidine and spermine contents were determined by high pressure liquid chromatography. Putrescine content was significantly elevated in all brain regions by ACTH_1–24 (approx 50%), and in the telencephalon by ACTH_4–10 At the dose tested ACTH_4–10 was less effective than ACTH_1–24. Telencephalic spermidine was also elevated (10%)by ACTH_1–24, but spermine content was not altered in any brain region. One injection of the long-acting ACTH_1–24 preparation elevated telencephalic putrescine (49%) 24 h post-injection. ACTH_1–24 (1 μg/g) in saline produced a peak elevation of all three telencephalic polyamines 6 h post-injection, while in the liver only putrescine was significantly elevated and reached a peak at 10h. Neither plasma polyamine nor ornithine concentrations were significantly altered by any of the treatments. Corticosterone, in both single and multiple injection regimens, failed to alter telencephalic polyamine content. Adrenalectomy, however, prevented the ACTH_1–24-induced increase in telencephalic polyamines. It is concluded that ACTH acts directly in the brain to increase cerebral polyamine concentrations. The possibility that adrenal hormones exert permissive effects on this action is discussed.     

A polyamine-conjugated peptide isolated from human plasma

When human plasma was fractionated by gel exclusion chromatography on Bio-Gel P-10, substantial quantities of putrescine and trace amounts of spermidine were consistently associated with a 4200 M_r peptide species. Putrescine was not removed from the peptide by extensive dialysis, desalting, multiple gel and ion exchange chromatographic procedures, nor by incubation with urea followed by trichloroacetic acid precipitation. No putrescine was detected unless the peptide was acid hydrolyzed. Incubation of plasma with ¹⁴C-labeled putrescine did not result in association of the label with the peptide. We conclude that these polyamines appear to be covalently bound to this major plasma peptide species. The amount of putrescine associated with the peptide is 10- to 40-fold the concentration of unbound plasma putrescine per equivalent amount of plasma. The peptide was purified to apparent homogeneity and was found to be a single chain composed of 32 amino acid residues with a combined molecular weight of 4180. Possible biological roles of this polyamine conjugated peptide are discussed.     

Water pollution by a land-based trout farm

In 1992, wastes from a land-based trout (Oncorhynchus mykiss) farm on a small stream in Brandenburg were investigated. This trout farm consists of 15 basins with a total volume of about 170 m³ using open water recirculation without water purification. The water supply from the stream is about 110 L/s and about 240 L/s are recycled by pumps. In 1991, the total production of rainbow trout was 20 t. Investigations included the discharge of nitrogen, phosphorus, COD and suspended matter resulting from the fish production, measured as the difference between inflow and outflow water. The average daily output was 466 g/t nitrogen, 157 g/t phosphorus, 3145 g/t COD and 30 L/t suspended dry matter. The feed conversion ratio was 1.33 kg/kg gain. These results indicated a reduction in waste discharge by about 53% for nitrogen and 42% for phosphorus compared to previous results in former Eastern Germany.     

Autosomal dominant polycystic kidney disease: Genetics, mutations and microRNAs

Autosomal dominant polycystic kidney disease (ADPKD) is a common, monogenic multi-systemic disorder characterized by the development of renal cysts and various extrarenal manifestations. Worldwide, it is a common cause of end-stage renal disease. ADPKD is caused by mutation in either one of two principal genes, PKD1 and PKD2, but has large phenotypic variability among affected individuals, attributable to PKD genic and allelic variability and, possibly, modifier gene effects. Recent studies have generated considerable information regarding the genetic basis and molecular diagnosis of this disease, its pathogenesis, and potential strategies for targeted treatment. The purpose of this article is to provide a comprehensive review of the genetics of ADPKD, including mechanisms responsible for disease development, the role of gene variations and mutations in disease presentation, and the putative role of microRNAs in ADPKD etiology. The emerging and important role of genetic testing and the advent of novel molecular diagnostic applications also are reviewed. This article is part of a Special Issue entitled: Polycystic Kidney Disease.     

Genetic correction of Werner syndrome gene reveals impaired pro‐angiogenic function and HGF insufficiency in mesenchymal stem cells

WRN mutation causes a premature aging disease called Werner syndrome (WS). However, the mechanism by which WRN loss leads to progeroid features evident with impaired tissue repair and regeneration remains unclear. To determine this mechanism, we performed gene editing in reprogrammed induced pluripotent stem cells (iPSCs) derived from WS fibroblasts. Gene correction restored the expression of WRN. WRN^+/+ mesenchymal stem cells (MSCs) exhibited improved pro‐angiogenesis. An analysis of paracrine factors revealed that hepatocyte growth factor (HGF) was downregulated in WRN^?/? MSCs. HGF insufficiency resulted in poor angiogenesis and cutaneous wound healing. Furthermore, HGF was partially regulated by PI3K/AKT signaling, which was desensitized in WRN^?/? MSCs. Consistently, the inhibition of the PI3K/AKT pathway in WRN^+/+ MSC resulted in reduced angiogenesis and poor wound healing. Our findings indicate that the impairment in the pro‐angiogenic function of WS‐MSCs is due to HGF insufficiency and PI3K/AKT dysregulation, suggesting trophic disruption between stromal and epithelial cells as a mechanism for WS pathogenesis.     

Evaluation of an improved RNA/DNA quantification method in a common carp (Cyprinus carpio Linnaeus 1758) larval feeding trial with Artemia,two nematodes (Panagrellus redivivus Linnaeus 1758, Panagrolaimus sp. Fuchs 1930) and dry feed

The RNA/DNA ratio commonly used as proxy for the nutritional condition of fish larvae is affected by RNA degradation during analysis. For evaluation of two strategies to improve RNA integrity, a three‐week feeding trial was carried out to assess the suitability of two nematode species (fam. Panagrolaimidae) as feed for newly hatched carp larvae (Cyprinus carpio) in comparison to Artemia nauplii (Artemia sp.) and a commercial dry feed. Aiming for an increased reproducibility of RNA/DNA determination, a high‐salt inactivation (RNA later) as well as a targeted approach with a recombinant RNase inhibitor were compared to the classical protocol using lab chip technology. Improved RNA integrity was observed with high‐salt inactivation when compared with a strategy applying a specific RNase inhibitor or the classic protocol. Carp larvae fed Artemia for 2 weeks and then dry feed for 1 week revealed the best overall growth performance as well as survival [83.0 ± 35.2 mg fresh weight (FW), 20.0 ± 2.4 mm total length (TL), 86.6 ± 11.7% survival]. Larvae fed the nematode species Panagrellus redivivus for 1 week and subsequently dry feed for 2 weeks (37.4 ± 29.1 mg FW, 14.7 ± 2.8 mm TL, 76.0 ± 6.0% survival) performed better than larvae fed with dry feed alone (28.2 ± 29.6 mg FW, 14.3 ± 2.9 mm TL, 54.3 ± 14.2% survival) or those receiving Panagrellus for 2 weeks. Between both nematode species, Panagrellus was a better feed with regard to growth performance and survival. RNA/DNA ratios ranged between 0.65 ± 0.27 (8 days post‐hatch) and 1.96 ± 0.63 (22 days post‐hatch) and were in the same treatment order as the other growth parameters. RNA/DNA ratios were significantly correlated with the growth rate, and decreasing RNA/DNA ratios in larger larvae may reflect decreasing growth rates with size rather than decreased nutritional status. Here, an improved RNA/DNA ratio protocol is presented in a feeding trial that reveals the suitability of nematodes as a first feed for common carp larvae.     

MicroRNA-29b/Tet1 regulatory axis epigenetically modulates mesendoderm differentiation in mouse embryonic stem cells

Ten eleven translocation (Tet) family-mediated DNA oxidation on 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) represents a novel epigenetic modification that regulates dynamic gene expression during embryonic stem cells (ESCs) differentiation. Through the role of Tet on 5hmC regulation in stem cell development is relatively defined, how the Tet family is regulated and impacts on ESCs lineage development remains elusive. In this study, we show non-coding RNA regulation on Tet family may contribute to epigenetic regulation during ESCs differentiation, which is suggested by microRNA-29b (miR-29b) binding sites on the Tet1 3′ untranslated region (3′ UTR). We demonstrate miR-29b increases sharply after embyoid body (EB) formation, which causes Tet1 repression and reduction of cellular 5hmC level during ESCs differentiation. Importantly, we show this miR-29b/Tet1 regulatory axis promotes the mesendoderm lineage formation both in vitro and in vivo by inducing the Nodal signaling pathway and repressing the key target of the active demethylation pathway, Tdg. Taken together, our findings underscore the contribution of small non-coding RNA mediated regulation on DNA demethylation dynamics and the differential expressions of key mesendoderm regulators during ESCs lineage specification. MiR-29b could potentially be applied to enrich production of mesoderm and endoderm derivatives and be further differentiated into desired organ-specific cells.