The Financial Status of North Dakota Farmers and Ranchers: January 1, 1985, Survey Results

Agricultural Finance,

Inactivation of Pmel Alters Melanosome Shape But Has Only a Subtle Effect on Visible Pigmentation

PMEL is an amyloidogenic protein that appears to be exclusively expressed in pigment cells and forms intralumenal fibrils within early stage melanosomes upon which eumelanins deposit in later stages. PMEL is well conserved among vertebrates, and allelic variants in several species are associated with reduced levels of eumelanin in epidermal tissues. However, in most of these cases it is not clear whether the allelic variants reflect gain-of-function or loss-of-function, and no complete PMEL loss-of-function has been reported in a mammal. Here, we have created a mouse line in which the Pmel gene has been inactivated (Pmel−/−). These mice are fully viable, fertile, and display no obvious developmental defects. Melanosomes within Pmel−/− melanocytes are spherical in contrast to the oblong shape present in wild-type animals. This feature was documented in primary cultures of skin-derived melanocytes as well as in retinal pigment epithelium cells and in uveal melanocytes. Inactivation of Pmel has only a mild effect on the coat color phenotype in four different genetic backgrounds, with the clearest effect in mice also carrying the brown/Tyrp1 mutation. This phenotype, which is similar to that observed with the spontaneous silver mutation in mice, strongly suggests that other previously described alleles in vertebrates with more striking effects on pigmentation are dominant-negative mutations. Despite a mild effect on visible pigmentation, inactivation of Pmel led to a substantial reduction in eumelanin content in hair, which demonstrates that PMEL has a critical role for maintaining efficient epidermal pigmentation

Mutations in or near the Transmembrane Domain Alter PMEL Amyloid Formation from Functional to Pathogenic

PMEL is a pigment cell-specific protein that forms physiological amyloid fibrils upon which melanins ultimately deposit in the lumen of the pigment organelle, the melanosome. Whereas hypomorphic PMEL mutations in several species result in a mild pigment dilution that is inherited in a recessive manner, PMEL alleles found in the Dominant white (DW) chicken and Silver horse (HoSi)—which bear mutations that alter the PMEL transmembrane domain (TMD) and that are thus outside the amyloid core—are associated with a striking loss of pigmentation that is inherited in a dominant fashion. Here we show that the DW and HoSi mutations alter PMEL TMD oligomerization and/or association with membranes, with consequent formation of aberrantly packed fibrils. The aberrant fibrils are associated with a loss of pigmentation in cultured melanocytes, suggesting that they inhibit melanin production and/or melanosome integrity. A secondary mutation in the Smoky chicken, which reverts the dominant DW phenotype, prevents the accumulation of PMEL in fibrillogenic compartments and thus averts DW–associated pigment loss; a secondary mutation found in the Dun chicken likely dampens a HoSi–like dominant mutation in a similar manner. We propose that the DW and HoSi mutations alter the normally benign amyloid to a pathogenic form that antagonizes melanosome function, and that the secondary mutations found in the Smoky and Dun chickens revert or dampen pathogenicity by functioning as null alleles, thus preventing the formation of aberrant fibrils. We speculate that PMEL mutations can model the conversion between physiological and pathological amyloid

A 2 × 2 factorial, randomised, open-label trial to determine the clinical and cost-effectiveness of hypertonic saline (HTS 6%) and carbocisteine for airway clearance versus usual care over 52 weeks in adults with bronchiectasis:a protocol for the CLEAR clinical trial

Background: Current guidelines for the management of bronchiectasis (BE) highlight the lack of evidence to recommend mucoactive agents, such as hypertonic saline (HTS) and carbocisteine, to aid sputum removal as part of standard care. We hypothesise that mucoactive agents (HTS or carbocisteine, or a combination) are effective in reducing exacerbations over a 52-week period, compared to usual care. Methods: This is a 52-week, 2 × 2 factorial, randomized, open-label trial to determine the clinical effectiveness and cost effectiveness of HTS 6% and carbocisteine for airway clearance versus usual care-the Clinical and cost-effectiveness of hypertonic saline (HTS 6%) and carbocisteine for airway clearance versus usual care (CLEAR) trial. Patients will be randomised to (1) standard care and twice-daily nebulised HTS (6%), (2) standard care and carbocisteine (750 mg three times per day until visit 3, reducing to 750 mg twice per day), (3) standard care and combination of twice-daily nebulised HTS and carbocisteine, or (4) standard care. The primary outcome is the mean number of exacerbations over 52 weeks. Key inclusion criteria are as follows: Adults with a diagnosis of BE on computed tomography, BE as the primary respiratory diagnosis, and two or more pulmonary exacerbations in the last year requiring antibiotics and production of daily sputum. Discussion: This trial's pragmatic research design avoids the significant costs associated with double-blind trials whilst optimising rigour in other areas of trial delivery. The CLEAR trial will provide evidence as to whether HTS, carbocisteine or both are effective and cost effective for patients with BE. Trial registration: EudraCT number: 2017-000664-14 (first entered in the database on 20 October 2017). ISRCTN.com, ISRCTN89040295. Registered on 6 July/2018. Funder: National Institute for Health Research, Health Technology Assessment Programme (15/100/01). Sponsor: Belfast Health and Social Care Trust. Ethics Reference Number: 17/NE/0339. Protocol version: V3.0 Final_14052018

Safety and Effectiveness of Meropenem in Infants With Suspected or Complicated Intra-abdominal Infections

Background. Intra-abdominal infections are common in young infants and lead to significant morbidity and mortality. Meropenem is a broad-spectrum antimicrobial with excellent activity against pathogens associated with intra-abdominal infections. The purpose of this study was to determine the safety and effectiveness of meropenem in young infants with suspected or complicated intra-abdominal infections

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Dissecting the PMEL amyloid: An example of functional vs. pathological amyloid

Within pigment granules of cells in the skin, hair, and eyes, fibrillar amyloid-like deposits can be found. These amyloid fibrils are composed of the pigment cell-specific protein PMEL, and are important for pigment cell function and health. Thus, PMEL fibrils represent a physiological form of amyloid, playing a functional and protective role in cells, in marked contrast to the toxicity associated to many other amyloidogenic proteins involved in neurodegenerative disorders, such as Amyloid Precursor Protein (APP) in Alzheimer, Prion protein (PrP) in Creutzfeldt-Jakob, and α-synuclein in Parkinson diseases. The purpose of this work was two-fold: to define the role of PMEL amyloid fibrils in pigment cell function and to determine the contribution of PMEL subdomains in the maintenance and specificity of amyloid formation within specialized intracellular compartments. Using a PMEL-/- transgenic mouse model, we find that while PMEL fibril formation is not required for pigment production per se, it is needed to maintain the structural integrity of the pigment organelle, the melanosome. In addition, using a combination of in vitro and in cellulo approaches, we identify a domain, PKD, within PMEL, as containing the key signals for both targeting PMEL to specialized fibrillogenic compartments and its conversion from a soluble to an amyloidogenic form. Moreover, our studies imply that underlying the lack of PMEL amyloid toxicity is the high degree of compartmentation and speed of fibrillogenesis, which in turn might provide a useful framework to further understand the difference between functional and pathological amyloid

Dissecting the PMEL amyloid: An example of functional vs. pathological amyloid

Within pigment granules of cells in the skin, hair, and eyes, fibrillar amyloid-like deposits can be found. These amyloid fibrils are composed of the pigment cell-specific protein PMEL, and are important for pigment cell function and health. Thus, PMEL fibrils represent a physiological form of amyloid, playing a functional and protective role in cells, in marked contrast to the toxicity associated to many other amyloidogenic proteins involved in neurodegenerative disorders, such as Amyloid Precursor Protein (APP) in Alzheimer, Prion protein (PrP) in Creutzfeldt-Jakob, and α-synuclein in Parkinson diseases. The purpose of this work was two-fold: to define the role of PMEL amyloid fibrils in pigment cell function and to determine the contribution of PMEL subdomains in the maintenance and specificity of amyloid formation within specialized intracellular compartments. Using a PMEL-/- transgenic mouse model, we find that while PMEL fibril formation is not required for pigment production per se, it is needed to maintain the structural integrity of the pigment organelle, the melanosome. In addition, using a combination of in vitro and in cellulo approaches, we identify a domain, PKD, within PMEL, as containing the key signals for both targeting PMEL to specialized fibrillogenic compartments and its conversion from a soluble to an amyloidogenic form. Moreover, our studies imply that underlying the lack of PMEL amyloid toxicity is the high degree of compartmentation and speed of fibrillogenesis, which in turn might provide a useful framework to further understand the difference between functional and pathological amyloid