A Bedouin kindred with infantile nephronophthisis demonstrates linkage to chromosome 9 by homozygosity mapping.

A novel type of infantile nephronophthisis was identified in an extended Bedouin family from Israel. This disease has an autosomal recessive mode of inheritance, with the phenotypic presentation ranging from a Potter-like syndrome to hyperechogenic kidneys, renal insufficiency, hypertension, and hyperkalemia. Affected individuals show rapid deterioration of kidney function, leading to end-stage renal failure within 3 years. Histopathologic examination of renal tissue revealed variable findings, ranging from infantile polycystic kidneys to chronic tubulointerstitial nephritis, fibrosis, and cortical microcysts. A known familial juvenile nephronophthisis locus on chromosome 2q13 and autosomal recessive polycystic kidney disease on chromosome 6p21.1-p12 were excluded by genetic linkage analysis. A genomewide screen for linkage was conducted by searching for a locus inherited by descent in all affected individuals. Pooled DNA samples from parents and unaffected siblings and individual DNA samples from four affected individuals were used as PCR templates with trinucleotide- and tetranucleotide-repeat polymorphic markers. Using this approach, we identified linkage to infantile nephronophthisis for markers on chromosome 9q22-31. The disorder maps to a 12.9-cM region flanked by markers D9S280 and GGAT3G09.     

Spectral characteristics of phytochrome in vivo and in vitro

The absorption maximum of the far-red absorbing form of phytochrome in the difference spectrum for phototransformation (Pfr max) was investigated in vivo and in in vitro pellets from dark grown Hordeum vulgare L. primary leaves. Exposure of pellets in Honda medium from tissue pre-irradiated with red light to far red light gave a Pfr max of 734 nm, a slightly longer wavelength than was seen in vivo (730 nm). After incubation as the red absorbing form of phytochrome (Pr) for 2 h at 0° C irradiation with red light showed that Pfr max had shifted to shorter wavelength (716 nm) in Honda medium. Further incubation as Pfr for 2 h at 0° C and irradiation with far red light showed that Pfr max had shifted to longer wavelength (726 nm). Similar shifts were also seen in other media, although the peak positions were different. Phytochrome remained pelletable throughout these experiments and Pfr max is compared to that of soluble phytochrome in similar media. The results are interpreted as indicating changes in molecular environment of the putative phytochrome membrane receptor site and that Pfr max can be used to probe the nature of this binding.Abbreviations D Dark - EDTA Ethylene diamine tetra-acetic acid - F far red light - MOPS N-morpholino-3-propane-sulphonic acid - P Phytochrome - Pr red absorbing form of P - Pfr far red absorbing form of P - Pfr max wavelength maximum of Pfr absorbance in a phototransformation difference spectrum - R red light     

Variations in the number of pituitary LHRH receptors correlated with altered responsiveness to LHRH

Isolated pituitary cells from metestrous, ovariectomized (OVX), and ovariectomized-estradiol treated (OVX-EB) rats were employed to study the gonadotropin response to luteinizing hormone-releasing hormone (LHRH) challenge and to quantitate LHRH receptors, using a labeled LHRH analog. Ovariectomy (3–4 weeks post castration) resulted in a reduction of LHRH receptor concentration from 34.4 ± 2.1 in metestrous females to 14.3 ± 0.9 fmoles/10⁶ cells. Concomitantly, the luteinizing hormone (LH) response to a near-maximal dose of LHRH (5 ng/ml) decreased from a 3-fold stimulation in intact females to 1.13-fold stimulation in cells from OVX rats. Replacement therapy with EB (50 ug/rat for 2 days) to OVX rats restored LH response and LHRH binding sites (a 2.5-fold stimulation in LH secretion and 32.0 ± 2.1 fmoles/10⁶ cells, respectively). The LH response to LHRH stimulation was not altered after one day of EB treatment although the number of LHRH binding sites was increased. The changes in the number of LHRH binding sites were not accompanied by any alterations in the affinity of the LHRH analog ($\text{K}{}_{\mathrm{d}}\text{? 0.5 × 10}{}^{\mathrm{?9}}\text{M}$). It is concluded that variations in LHRH receptor number reflect the degree of pituitary sensitivity to LHRH and it may suggest that LHRH and estradiol modulation of gonadotropin release is mediated by these receptors.     

The cloning and developmental expression of unconventional myosin IXA (MYO9A) a gene in the Bardet-Biedl syndrome (BBS4) region at chromosome 15q22-q23.

Bardet-Biedl Syndrome (BBS) is a heterogeneous, autosomal recessive disorder characterized by mental retardation, obesity, retinitis pigmentosa, syndactyly and/or polydactyly, short stature, and hypogenitalism and is caused by mutations at a number of distinct loci. Using a positional cloning approach for identifying the BBS4 (chromosome 15) gene, we identified and cloned an unconventional myosin gene, myosin IXA (HGMW-approved symbol MYO9A). Since mutations in unconventional myosins are known to cause several human diseases, and since mutations of unconventional myosin VIIa cause retinal degeneration, we evaluated myosin IXA as a candidate for BBS. We exploited PCR-based techniques to clone a 8473-nt cDNA for myosin IXA. A 7644-bp open reading frame predicts a protein with all the hallmarks of class IX unconventional myosins. Human Northern blot analysis and in situ hybridization of mouse embryos reveal that myosin IXA is expressed in many tissues consistent with BBS. Intron/exon boundaries were identified, and myosin IXA DNA and RNA from BBS4 patients were evaluated for mutation.     

Dynamics of jamming avoidance in echolocating bats

Animals using active sensing systems such as echolocation or electrolocation may experience interference from the signals of neighbouring conspecifics, which can be offset by a jamming avoidance response (JAR). Here, we report JAR in one echolocating bat (Tadarida teniotis: Molossidae) but not in another (Taphozous perforatus: Emballonuridae) when both flew and foraged with conspecifics. In T. teniotis, JAR consisted of shifts in the dominant frequencies of echolocation calls, enhancing differences among individuals. Larger spectral overlap of signals elicited stronger JAR. Tadarida teniotis showed two types of JAR: (i) for distant conspecifics: a symmetric JAR, with lower- and higher-frequency bats shifting their frequencies downwards and upwards, respectively, on average by the same amount; and (ii) for closer conspecifics: an asymmetric JAR, with only the upper-frequency bat shifting its frequency upwards. In comparison, 'wave-type' weakly electric fishes also shift frequencies of discharges in a JAR, but unlike T. teniotis, the shifts are either symmetric in some species or asymmetric in others. We hypothesize that symmetric JAR in T. teniotis serves to avoid jamming and improve echolocation, whereas asymmetric JAR may aid communication by helping to identify and locate conspecifics, thus minimizing chances of mid-air collisions.     

Guilt, fear, stigma and knowledge gaps: ethical issues in public health communication interventions

Public health communication campaigns have been credited with helping raise awareness of risk from chronic illness and new infectious diseases and with helping promote the adoption of recommended treatment regimens. Yet many aspects of public health communication interventions have escaped the scrutiny of ethical discussions. With the transference of successful commercial marketing communication tactics to the realm of public health, consideration of ethical issues becomes an essential component in the development and application of public health strategies. Ethical issues in public health communication are explored as they relate to eight topics: 'targeting' and 'tailoring' public health messages to particular population segments; obtaining the equivalence of informed consent; the use of persuasive communication tactics; messages on responsibility and culpability; messages that apply to harm reduction; and three types of unintended adverse effects associated with public health communication activities that may label and stigmatise, expand social gaps, and promote health as a value. We suggest that an ethical analysis should be applied to each phase of the public health communication process in order to identify ethical dilemmas that may appear subtle, yet reflect important concerns regarding potential effects of public health communication interventions on individuals and society as a whole.     

REST and its corepressors mediate plasticity of neuronal gene chromatin throughout neurogenesis

Regulation of neuronal gene expression is critical to central nervous system development. Here, we show that REST regulates the transitions from pluripotent to neural stem/progenitor cell and from progenitor to mature neuron. In the transition to progenitor cell, REST is degraded to levels just sufficient to maintain neuronal gene chromatin in an inactive state that is nonetheless poised for expression. As progenitors differentiate into neurons, REST and its co-repressors dissociate from the RE1 site, triggering activation of neuronal genes. In some genes, the level of expression is adjusted further in neurons by CoREST/MeCP2 repressor complexes that remain bound to a site of methylated DNA distinct from the RE1 site. Expression profiling based on this mechanism indicates that REST defines a gene set subject to plasticity in mature neurons. Thus, a multistage repressor mechanism controls the orderly expression of genes during development while still permitting fine tuning in response to specific stimuli.     

Scytalidium dimidiatum an opportunistic fungus for both man and Mangifera indica trees in Venezuela

The purpose of this study was to confirm the presence of Scytalidium dimidiatum on Mangifera indica (mango) trees, in a plantation managed by a diabetic patient with a white grain mycetoma of the foot caused by the same fungus. Samples from necrotic apices, roots, burned leaves and rotten stems from eight trees were processed by the Smith and Furcolow's mineral oil technique (modified). Several isolates from the apex material and clinical samples from the diabetic patient isolated in pure culture a fungus with the macroscopic and microscopic characteristics of that in S. dimidiatum. This fungus should be considered as an opportunistic microorganism for both humans and M. indica.