Dry matter intake and feed efficiency of heifers from 4 dairy breed types grazing organic grass and grass-birdsfoot trefoil mixed pastures.

Insufficient dry matter intake (DMI) of pasture by dairy cattle is a major factor limiting growth and milk production; however, it has been hypothesized that some dairy breeds may be more efficient grazers than others. This study was conducted to determine whether dairy breed types differ in DMI and feed efficiency when grazing either grass monoculture or grass-legume mixed pastures. The experiment compared 4 different dairy breed types (Jersey, Holstein, Holstein-Jersey crossbreds, and Montbéliarde-Swedish Red-Holstein 3-breed crossbreds) and 2 levels of pasture type [grass monoculture (MONO) and grass-birdsfoot trefoil (BFT) mixture (MX)] for a total of 8 treatments. Pastures were rotationally stocked with groups of 4 prepubertal heifers for 105 d for 3 yr, and DMI was determined from herbage disappearance. Feed conversion efficiency (FCE) and residual feed intake (RFI) were then derived from DMI, and heifer body weights (BW) and normalized to animal units (AU) as 40% metabolic mature BW of the corresponding dairy breed type to account for inherent differences in size and growth rates. We observed differences in DMI and feed efficiency among breed types and between pasture types. On average, Holsteins had the greatest overall DMI (4.4 kg/AU), followed by intermediate DMI by the crossbreds (4.0 kg/AU), and Jerseys had the least DMI (3.6 kg/AU). Heifers grazing MX pastures had on average 22% greater DMI than those grazing MONO, but heifers on grass monocultures were more efficient in converting DMI to BW gain (i.e., RFI/AU of 0.27 and -0.27, respectively; more negative RFI numbers indicate less DMI to achieve the expected gains). Overall, Jerseys had the most favorable feed efficiency; however, ranking of Holsteins and crossbreds depended upon the feed efficiency metric. This study is one of the first to compare the interaction of dairy breed and pasture quality on grazing efficiency. However, the lack of a breed type × pasture type interaction for DMI, FCE, or RFI indicated that none of these dairy breed types were better adapted than another breed type to pastures with contrasting levels of nutritive value.

Multi-omic profiling of pituitary thyrotropic cells and progenitors.

BACKGROUND: The pituitary gland is a neuroendocrine organ containing diverse cell types specialized in secreting hormones that regulate physiology. Pituitary thyrotropes produce thyroid-stimulating hormone (TSH), a critical factor for growth and maintenance of metabolism. The transcription factors POU1F1 and GATA2 have been implicated in thyrotrope fate, but the transcriptomic and epigenomic landscapes of these neuroendocrine cells have not been characterized. The goal of this work was to discover transcriptional regulatory elements that drive thyrotrope fate. RESULTS: We identified the transcription factors and epigenomic changes in chromatin that are associated with differentiation of POU1F1-expressing progenitors into thyrotropes using cell lines that represent an undifferentiated Pou1f1 lineage progenitor (GHF-T1) and a committed thyrotrope line that produces TSH (TαT1). We compared RNA-seq, ATAC-seq, histone modification (H3K27Ac, H3K4Me1, and H3K27Me3), and POU1F1 binding in these cell lines. POU1F1 binding sites are commonly associated with bZIP transcription factor consensus binding sites in GHF-T1 cells and Helix-Turn-Helix (HTH) or basic Helix-Loop-Helix (bHLH) factors in TαT1 cells, suggesting that these classes of transcription factors may recruit or cooperate with POU1F1 binding at unique sites. We validated enhancer function of novel elements we mapped near Cga, Pitx1, Gata2, and Tshb by transfection in TαT1 cells. Finally, we confirmed that an enhancer element near Tshb can drive expression in thyrotropes of transgenic mice, and we demonstrate that GATA2 enhances Tshb expression through this element. CONCLUSION: These results extend the ENCODE multi-omic profiling approach to the pituitary gland, which should be valuable for understanding pituitary development and disease pathogenesis.

Ibrexafungerp: An orally active ß-1,3-glucan synthesis inhibitor.

We previously reported medicinal chemistry efforts that identified MK-5204, an orally efficacious ß-1,3-glucan synthesis inhibitor derived from the natural product enfumafungin. Further extensive optimization of the C2 triazole substituent identified 4-pyridyl as the preferred replacement for the carboxamide of MK-5204, leading to improvements in antifungal activity in the presence of serum, and increased oral exposure. Reoptimizing the aminoether at C3 in the presence of this newly discovered C2 substituent, confirmed that the (R) t-butyl, methyl aminoether of MK-5204 provided the best balance of these two key parameters, culminating in the discovery of ibrexafungerp, which is currently in phase III clinical trials. Ibrexafungerp displayed significantly improved oral efficacy in murine infection models, making it a superior candidate for clinical development as an oral treatment for Candida and Aspergillus infections.

The effects of organic grass and grass-birdsfoot trefoil pastures on Jersey heifer development: Herbage characteristics affecting intake.

Low dietary energy and decreased intake of herbage have been attributed to the reduced performance of grazing dairy cattle. We hypothesized that grasses with inherently greater energy would interact in a complementary way with condensed tannins (CT) in birdsfoot trefoil to increase herbage intake by grazing dairy heifers. Eight pasture treatments comprising high-sugar perennial ryegrass (Lolium perenne L.), orchardgrass (Dactylis glomerata L.), meadow bromegrass (Bromus riparius Rehmann), and tall fescue [Schendonorus arundinaceus (Schreb.) Dumort] were established in Lewiston, Utah as monocultures and binary mixtures with birdsfoot trefoil (Lotus corniculatus L.; BFT). Pasture treatments were rotationally stocked by Jersey heifers for 105 d in 2017 and 2018, and herbage samples were collected pre- and postgrazing for each 7-d grazing period and analyzed for herbage mass, nutritive value, and apparent herbage intake. We observed differences among pasture treatments in herbage quantity and nutritive value, as well as differences in herbage intake by grazing Jersey heifers. On average, grass-BFT mixtures had greater herbage intake than grass monocultures, and every grass-BFT treatment individually had greater herbage intake than their respective grass monocultures. Using multivariate analyses, we determined that approximately 50% of the variation in herbage intake was due to nutritive and physical herbage characteristics, with the most explanatory being characteristics related to fiber and energy, followed by those related to the percent of BFT in the herbage. Grass monocultures exhibited a range of inherent dietary energy, but there was indication that an imbalance of energy to crude protein (e.g., protein deficient) reduced intake of grass monocultures. Moreover, there was some evidence of a complementary effect between increased dietary energy and CT; however, low CT levels made it impossible to determine the effect of CT on herbage intake per se. This study confirmed that chemical and physical characteristics inherent to different pasture species have a large effect on herbage intake by grazing cattle. Pastures planted to binary mixtures of nutritious grasses and birdsfoot trefoil increase herbage intake of temperate pastures by grazing Jersey heifers.

The effects of organic grass and grass-birdsfoot trefoil pastures on Jersey heifer development: Heifer growth, performance, and economic impact.

Dairy heifers developed in certified organic programs, especially those utilizing pasture-based management schemes, have lower rates of gain than heifers raised in nonorganic confinement production systems in temperate climates, such as in the Intermountain West region of the United States. This study investigates the effects that different forages in a rotational grazing system have on development of organically raised Jersey heifers. Over 3 years, 210 yearling Jersey heifers were randomly assigned to one of 9 treatments, including a conventional confinement control where animals were fed a total mixed ration or one of 8 pasture treatments: Cache Meadow bromegrass (Bromus riparius Rehmann), QuickDraw orchard grass (Dactylis glomerata L.), Amazon perennial ryegrass (Lolium perenne L.), or Fawn tall fescue (Schendonorus arundinaceus [Schreb.] Dumort) and each individual grass interseeded with birdsfoot trefoil (Lotus corniculatus L., BFT). Each treatment had 3 blocks/yr over the 3-yr period, with each block having a 0.4 ha pasture of each treatment. Every 35 d, over a 105-d period, heifers were weighed and measured for hip height, and blood samples were collected to determine serum insulin-like growth factor-1 and blood urea nitrogen concentrations. Fecal egg counts were also assessed. Heifer body weight (BW), blood urea nitrogen, and insulin-like growth factor-1 concentrations were affected by treatment when analyzed over time. Heifers on grass-BFT pastures had increased BW compared with heifers on monoculture grass pastures. Heifers receiving a total mixed ration or perennial ryegrass+BFT had increased BW gain over the 105-d period compared with heifers grazing tall fescue+BFT, orchard grass, perennial ryegrass, meadow bromegrass, or tall fescue. Individually for all grass species, heifers grazing +BFT pastures had greater ending BW and weight gain than heifers grazing the respective grass monocultures. Furthermore, weight gain for heifers on perennial ryegrass+BFT, meadow bromegrass+BFT, and orchard grass+BFT were not different from those on a total mixed ration. Heifers grazing grass-BFT pastures had increased blood urea nitrogen compared with heifers grazing monoculture grass pastures. Heifer hip height and fecal egg counts were not affected by treatment. These results show that the addition of BFT to organic pasture improves growth of grazing replacement heifers. Economic analyses also demonstrate that interseeding grass pastures with BFT results in an increased economic return compared with grazing monoculture grass pastures. Grass pastures interseeded with BFT may be a sustainable option to achieve adequate growth of Jersey heifers raised in an organic pasture scenario in a temperate climate.

Baryon Acoustic Oscillations from Integrated Neutral Gas Observations: an instrument to observe the 21cm hydrogen line in the redshift range 0.13 < z < 0.45 - status update.

BINGO (BAO from Integrated Neutral Gas Observations) is a unique radio telescope designed to map the intensity of neutral hydrogen distribution at cosmological distances, making the first detection of Baryon Acoustic Oscillations (BAO) in the frequency band 980 MHz - 1260 MHz, corresponding to a redshift range 0.127 < z < 0.449. BAO is one of the most powerful probes of cosmological parameters and BINGO was designed to detect the BAO signal to a level that makes it possible to put new constraints on the equation of state of dark energy. The telescope will be built in Paraíba, Brazil and consists of two \thicksim 40m mirrors, a feedhorn array of 50 horns, and no moving parts, working as a drift-scan instrument. It will cover a 15 ^{\circ} ∘ declination strip centered at \sim \delta ∼ δ =-15 ^{\circ} ∘ , mapping \sim ∼ 5400 square degrees in the sky. The BINGO consortium is led by University of São Paulo with co-leadership at National Institute for Space Research and Campina Grande Federal University (Brazil). Telescope subsystems have already been fabricated and tested, and the dish and structure fabrication are expected to start in late 2020, as well as the road and terrain preparation.

MK-5204: An orally active ß-1,3-glucan synthesis inhibitor.

Our previously reported efforts to produce an orally active ß-1,3-glucan synthesis inhibitor through the semi-synthetic modification of enfumafungin focused on replacing the C2 acetoxy moiety with an aminotetrazole and the C3 glycoside with a N,N-dimethylaminoether moiety. This work details further optimization of the C2 heterocyclic substituent, which identified 3-carboxamide-1,2,4-triazole as a replacement for the aminotetrazole with comparable antifungal activity. Alkylation of either the carboxamidetriazole at C2 or the aminoether at C3 failed to significantly improve oral efficacy. However, replacement of the isopropyl alpha amino substituent with a t-butyl, improved oral exposure while maintaining antifungal activity. These two structural modifications produced MK-5204, which demonstrated broad spectrum activity against Candida species and robust oral efficacy in a murine model of disseminated Candidiasis without the N-dealkylation liability observed for the previous lead.

Genome-Wide Association and Prediction of Traits Related to Salt Tolerance in Autotetraploid Alfalfa (Medicago sativa L.).

Soil salinity is a growing problem in world production agriculture. Continued improvement in crop salt tolerance will require the implementation of innovative breeding strategies such as marker-assisted selection (MAS) and genomic selection (GS). Genetic analyses for yield and vigor traits under salt stress in alfalfa breeding populations with three different phenotypic datasets was assessed. Genotype-by-sequencing (GBS) developed markers with allele dosage and phenotypic data were analyzed by genome-wide association studies (GWAS) and GS using different models. GWAS identified 27 single nucleotide polymorphism (SNP) markers associated with salt tolerance. Mapping SNPs markers against the Medicago truncatula reference genome revealed several putative candidate genes based on their roles in response to salt stress. Additionally, eight GS models were used to estimate breeding values of the training population under salt stress. Highest prediction accuracies and root mean square errors were used to determine the best prediction model. The machine learning methods (support vector machine and random forest) performance best with the prediction accuracy of 0.793 for yield. The marker loci and candidate genes identified, along with optimized GS prediction models, were shown to be useful in improvement of alfalfa with enhanced salt tolerance. DNA markers and the outcome of the GS will be made available to the alfalfa breeding community in efforts to accelerate genetic gains, in the development of biotic stress tolerant and more productive modern-day alfalfa cultivars.

A framework to measure the wildness of managed large vertebrate populations.

As landscapes continue to fall under human influence through habitat loss and fragmentation, fencing is increasingly being used to mitigate anthropogenic threats and enhance the commercial value of wildlife. Subsequent intensification of management potentially erodes wildness by disembodying populations from landscape-level processes, thereby disconnecting species from natural selection. Tools are needed to measure the degree to which populations of large vertebrate species in formally protected and privately owned wildlife areas are self-sustaining and free to adapt. We devised a framework to measure such wildness based on 6 attributes relating to the evolutionary and ecological dynamics of vertebrates (space, disease and parasite resistance, exposure to predation, exposure to limitations and fluctuations of food and water supply, and reproduction). For each attribute, we set empirical, species-specific thresholds between 5 wildness states based on quantifiable management interventions. We analysed data from 205 private wildlife properties with management objectives spanning ecotourism to consumptive utilization to test the framework on 6 herbivore species representing a range of conservation statuses and commercial values. Wildness scores among species differed significantly, and the proportion of populations identified as wild ranged from 12% to 84%, which indicates the tool detected site-scale differences both among populations of different species and populations of the same species under different management regimes. By quantifying wildness, this framework provides practitioners with standardized measurement units that link biodiversity with the sustainable use of wildlife. Applications include informing species management plans at local scales; standardizing the inclusion of managed populations in red-list assessments; and providing a platform for certification and regulation of wildlife-based economies. Applying this framework may help embed wildness as a normative value in policy and mitigate the shifting baseline of what it means to truly conserve a species.

Un Marco de Trabajo para Medir el Estado Salvaje de Poblaciones de Vertebrados Mayores bajo Manejo Resumen Conforme los paisajes siguen cayendo bajo la influencia del humano por causa de la pérdida del hábitat y la fragmentación, cada vez se usa más el encercado para mitigar las amenazas antropogénicas o incrementar el valor comercial de la fauna. La intensificación subsecuente del manejo tiene el potencial para erosionar el estado salvaje al desincorporar a las poblaciones de los procesos a nivel de paisaje, desconectando así a las especies del proceso de selección natural. Por lo tanto, se necesitan herramientas para medir el grado al cual las poblaciones de especies de vertebrados mayores dentro de áreas de fauna protegidas y privadas son autosostenibles y libres de adaptarse. Diseñamos un marco de trabajo para medir dicho estado salvaje con base en seis atributos relacionados con las dinámicas evolutivas y ecológicas de los vertebrados (espacio, resistencia a las enfermedades y a los parásitos, exposición a la depredación, exposición a las limitaciones y fluctuaciones en las reservas de agua y alimentos, y reproducción). Para cada atributo, establecimos umbrales empíricos y específicos por especie entre cinco estados salvajes basados en las intervenciones de manejo cuantificables. Usamos datos de 205 propiedades privadas de fauna con objetivos de manejo que abarcan desde el ecoturismo hasta el uso para consumo para probar el marco de trabajo en seis especies de herbívoros con una gama de estados de conservación y valores comerciales. Los puntajes de estado salvaje entre las especies difirieron significativamente y la proporción de poblaciones identificadas como salvajes osciló del 12% al 84%, lo que indica que la herramienta detectó diferencias a escala de sitio entre las poblaciones de diferentes especies y las poblaciones de la misma especie bajo diferentes regímenes de manejo. Si cuantificamos el estado salvaje, este marco de trabajo les proporciona a los practicantes las unidades de medida estandarizadas que vinculan a la biodiversidad con el uso sostenible de la fauna. Las aplicaciones de este marco de trabajo incluyen informar a los planes de manejo de las especies a escalas locales; estandarizar la inclusión de las poblaciones manejadas en las evaluaciones de listas rojas; y proporcionar una plataforma para la certificación y regulación de las economías basadas en la fauna. La aplicación de este marco de trabajo puede ayudar a insertar a la fauna como un valor normativo dentro de la política y a mitigar la línea base cambiante de lo que significa conservar verdaderamente a una especie.

Cyclosporin derivatives inhibit hepatitis B virus entry without interfering with NTCP transporter activity.

BACKGROUND & AIMS: The sodium taurocholate co-transporting polypeptide (NTCP) is the main target of most hepatitis B virus (HBV) specific entry inhibitors. Unfortunately, these agents also block NTCP transport of bile acids into hepatocytes, and thus have the potential to cause adverse effects. We aimed to identify small molecules that inhibit HBV entry while maintaining NTCP transporter function. METHODS: We characterized a series of cyclosporine (CsA) derivatives for their anti-HBV activity and NTCP binding specificity using HepG2 cells overexpressing NTCP and primary human hepatocytes. The four most potent derivatives were tested for their capacity to prevent HBV entry, but maintain NTCP transporter function. Their antiviral activity against different HBV genotypes was analysed. RESULTS: We identified several CsA derivatives that inhibited HBV infection with a sub-micromolar IC50. Among them, SCY446 and SCY450 showed low activity against calcineurin (CN) and cyclophilins (CyPs), two major CsA cellular targets. This suggested that instead, these compounds interacted directly with NTCP to inhibit viral attachment to host cells, and have no immunosuppressive function. Importantly, we found that SCY450 and SCY995 did not impair the NTCP-dependent uptake of bile acids, and inhibited multiple HBV genotypes including a clinically relevant nucleoside analog-resistant HBV isolate. CONCLUSIONS: This is the first example of small molecule selective inhibition of HBV entry with no decrease in NTCP transporter activity. It suggests that the anti-HBV activity can be functionally separated from bile acid transport. These broadly active anti-HBV molecules are potential candidates for developing new drugs with fewer adverse effects. LAY SUMMARY: In this study, we identified new compounds that selectively inhibited hepatitis B virus (HBV) entry, and did not impair bile acid uptake. Our evidence offers a new strategy for developing anti-HBV drugs with fewer side effects.

SCY-078 Is Fungicidal against Candida Species in Time-Kill Studies.

SCY-078 is an orally bioavailable ß-1,3-glucan synthesis inhibitor (GSI) and the first-in-class of structurally novel triterpene antifungals in clinical development for treating candidemia and invasive candidiasis. In vitro susceptibilities by broth microdilution, antifungal carryover, and time-kill dynamics were determined for three reference (ATCC) strains (Candida albicans 90028, Candida parapsilosis 90018, and Candida tropicalis 750), a quality-control (QC) strain (Candida krusei 6258), and four other strains (C. albicans MYA-2732, 64124, and 76485 and Candida glabrata 90030). Caspofungin (CASP), fluconazole (FLC), and voriconazole (VRC) were comparators. For time-kill experiments, SCY-078 and CASP were evaluated at 0.25, 1, 2, 4, 8, and 16 times the MIC80, and FLU and VRC were evaluated at 4× MIC80 The time to reach 50%, 90%, and 99.9% reduction in the number of CFUs from the starting inoculum was determined. Net change in the number of CFU per milliliter was used to determine 50% and 90% effective concentrations and maximum effect (EC50, EC90, and Emax, respectively). The SCY-078 MIC range was between 0.0625 and 1 µg/ml and generally similar to that of CASP. Antifungal carryover was not observed for SCY-078. SCY-078 was fungicidal against seven isolates at ≥4× MIC (kill of ≥3 log10) and achieved a 1.7-log10 reduction in CFU count/milliliter against C. albicans 90028. CASP behaved similarly against each isolate and achieved a 1.5-log10 reduction in the number of CFU/milliliter against C. albicans 90028. Reductions of 50% in CFU count/milliliter were achieved rapidly (1 to 2.8 h); fungicidal endpoints were reached at 12.1 to 21.8 h at ≥4× MIC. EC90 was reached at ∼5× MIC at each time point to 24 h. The EC50 and EC90 values were generally similar (8 to 24 h). Time-kill behavior of CASP was similar to that of SCY-078. FLC and VRC were fungistatic. Overall, SCY-078 has primarily fungicidal activity against Candida spp. and behaved comparably to CASP.

Preclinical Pharmacokinetics and Pharmacodynamic Target of SCY-078, a First-in-Class Orally Active Antifungal Glucan Synthesis Inhibitor, in Murine Models of Disseminated Candidiasis.

SCY-078 (MK-3118) is a novel, semisynthetic derivative of enfumafungin and represents the first compound of the triterpene class of antifungals. SCY-078 exhibits potent inhibition of ß-(1,3)-d-glucan synthesis, an essential cell wall component of many pathogenic fungi, including Candida spp. and Aspergillus spp. SCY-078 is currently in phase 2 clinical development for the treatment of invasive fungal diseases. In vitro disposition studies to assess solubility, intestinal permeability, and metabolic stability were predictive of good oral bioavailability. Preclinical pharmacokinetic studies were consistent with once-daily administration to humans. After intravenous delivery, plasma clearance in rodents and dogs was low, representing <15% and <25% of hepatic blood flow, respectively. The terminal elimination-phase half-life was 5.5 to 8.7 h in rodents, and it was ∼9.3 h in dogs. The volume of distribution at steady-state was high (4.7 to 5.3 liters/kg), a finding suggestive of extensive tissue distribution. Exposure of SCY-078 in kidney tissue, a target organ for invasive fungal disease such as candidiasis, exceeded plasma by 20- to 25-fold for the area under the concentration-time curve from 0 h to infinity (AUC0-∞) and Cmax SCY-078 achieved efficacy endpoints following oral delivery across multiple murine models of disseminated candidiasis. The pharmacokinetic/pharmacodynamic indices Cmax/MIC and AUC/MIC correlated with outcome. Target therapeutic exposure, expressed as the plasma AUC0-24, was comparable across models, with an upper value of 11.2 µg·h/ml (15.4 µM·h); the corresponding mean value for free drug AUC/MIC was ∼0.75. Overall, these results demonstrate that SCY-078 has the oral and intravenous (i.v.) pharmacokinetic properties and potency in murine infection models of disseminated candidiasis to support further investigation as a novel i.v. and oral treatment for invasive fungal diseases.

Synthesis and evaluation of analogs of 5'-(((Z)-4-amino-2-butenyl)methylamino)-5'-deoxyadenosine (MDL 73811, or AbeAdo) - An inhibitor of S-adenosylmethionine decarboxylase with antitrypanosomal activity.

We describe our efforts to improve the pharmacokinetic properties of a mechanism-based suicide inhibitor of the polyamine biosynthetic enzyme S-adenosylmethionine decarboxylase (AdoMetDC), essential for the survival of the eukaryotic parasite Trypanosoma brucei responsible for Human African Trypanosomiasis (HAT). The lead compound, 5'-(((Z)-4-amino-2-butenyl)methylamino)-5'-deoxyadenosine (1, also known as MDL 73811, or AbeAdo), has curative efficacy at a low dosage in a hemolymphatic model of HAT but displayed no demonstrable effect in a mouse model of the CNS stage of HAT due to poor blood-brain barrier permeation. Therefore, we prepared and evaluated an extensive set of analogs with modifications in the aminobutenyl side chain, the 5'-amine, the ribose, and the purine fragments. Although we gained valuable structure-activity insights from this comprehensive dataset, we did not gain traction on improving the prospects for CNS penetration while retaining the potent antiparasitic activity and metabolic stability of the lead compound 1.

Semi-synthesis of cyclosporins.

BACKGROUND: Since its isolation in 1970, and discovery of its potent inhibitory activity on T-cell proliferation, cyclosporin A (CsA) has been shown to play a significant role in diverse fields of biology. Furthermore, chemical modification of CsA has led to analogs with distinct biological activities associated with its protein receptor family, cyclophilins. SCOPE OF REVIEW: This review systematically collates the synthetic chemistry performed at each of the eleven amino acids, and provides examples of the utility of such transformations. The various modifications of CsA are traced from early, modest chemistry performed at the unique Bmt residue, through the remarkable use of a polyanion enolate that can be stereoselectively manipulated, and onto application of more recently developed olefin metathesis chemistry to prepare new CsA derivatives with unexpected biological activity. MAJOR CONCLUSIONS: The myriad biological activities of CsA and its synthetic derivatives have inspired the development of new approaches to modify the CsA ring. In turn, these new CsA derivatives have served as tools in the discovery of new roles for cyclophilins. GENERAL SIGNIFICANCE: This review provides information on the types of cyclosporin derivatives that are available to the many biologists working in this field, and should be of value to the medicinal chemist trying to discover drugs based on CsA. This article is part of a Special Issue entitled Proline-directed foldases: Cell signaling catalysts and drug targets.

A simple model for pollen-parent fecundity distributions in bee-pollinated forage legume polycrosses.

A simple Weibull distribution based empirical model that predicts pollen-parent fecundity distributions based on polycross size alone has been developed in outbred forage legume species for incorporation into quantitative genetic theory. Random mating or panmixis is a fundamental assumption in quantitative genetic theory. Random mating is sometimes thought to occur in actual fact, although a large body of empirical work shows that this is often not the case in nature. Models have been developed to explain many non-random mating phenomena. This paper measured pollen-parent fecundity distributions among outbred perennial forage legume species [autotetraploid alfalfa (Medicago sativa L.), autohexaploid kura clover (Trifolium ambiguum M. Bieb.), and diploid red clover (Trifolium pratense L.)] in ten polycrosses ranging in size (N) from 9 to 94 pollinated with bee pollinators [Bumble Bees (Bombus impatiens Cr.) and leafcutter bees (Megachile rotundata F.)]. A Weibull distribution best fit the observed pollen-parent fecundity distributions. After standardizing data among the 10 polycrosses, a single Weibull distribution-based model was obtained with an R (2) of 0.978. The model is able to predict pollen-parent fecundity distributions based on polycross size alone. The model predicts that the effective polycross size will be approximately 9 % smaller than under random mating (i.e., N e/N ~ 0.91). The model is simple and can easily be incorporated into other models or simulations requiring a pollen-parent fecundity distribution. Further work is needed to determine how widely applicable the model is.

Novel orally active inhibitors of ß-1,3-glucan synthesis derived from enfumafungin.

The clinical success of the echinocandins, which can only be administered parentally, has validated ß-1,3-glucan synthase (GS) as an antifungal target. Semi-synthetic modification of enfumafungin, a triterpene glycoside natural product, was performed with the aim of producing a new class of orally active GS inhibitors. Replacement of the C2 acetoxy moiety with various heterocycles did not improve GS or antifungal potency. However, replacement of the C3 glycoside with an aminoether moiety dramatically improved oral pharmacokinetic (PK) properties while maintaining GS and antifungal potency. Installing an aminotetrazole at C2 in conjunction with an N-alkylated aminoether at C3 produced derivatives with significantly improved GS and antifungal potency that exhibited robust oral efficacy in a murine model of disseminated candidiasis.

Combinatorial Ubiquitination REal-time PROteolysis (CURE-PROs): A Modular Platform for Generating Reversible, Self-Assembling Bifunctional Targeted Degraders.

Proteolysis-Targeting Chimeras (PROTACs) are bifunctional molecules that bring a target protein and an E3 ubiquitin ligase into proximity to append ubiquitin, thus directing target degradation. Although numerous PROTACs have entered clinical trials, their development remains challenging, and their large size can produce poor drug-like properties. To overcome these limitations, we have modified our Coferon platform to generate Combinatorial Ubiquitination REal-time PROteolysis (CURE-PROs). CURE-PROs are small molecule degraders designed to self-assemble through reversible bio-orthogonal linkers to form covalent heterodimers. By modifying known ligands for Cereblon, MDM2, VHL, and BRD with complementary phenylboronic acid and diol/catechol linkers, we have successfully created CURE-PROs that direct degradation of BRD4 both in vitro and in vivo. The combinatorial nature of our platform significantly reduces synthesis time and effort to identify the optimal linker length and E3 ligase partner to each target and is readily amenable to screening for new targets.

Cyclophilin inhibitors as antiviral agents.

Cyclophilins (Cyps) are ubiquitous proteins that effect the cis-trans isomerization of Pro amide bonds, and are thus crucial to protein folding. CypA is the most prevalent of the ~19 human Cyps, and plays a crucial role in viral infectivity, most notably for HIV-1 and HCV. Cyclophilins have been shown to play key roles in effective replication of a number of viruses from different families. A drug template for CypA inhibition is cyclosporine A (CsA), a cyclic undecapeptide that simultaneously binds to both CypA and the Ca(2+)-dependent phosphatase calcineurin (CN), and can attenuate immune responses. Synthetic modifications of the CsA scaffold allows for selective binding to CypA and CN separately, thus providing access to novel, non-immunosuppressive antiviral agents.

A topical aqueous calcineurin inhibitor for the treatment of naturally occurring keratoconjunctivitis sicca in dogs.

PURPOSE: The purpose of this study was to evaluate the efficacy of an aqueous calcineurin inhibitor, SCY-641, in the treatment of naturally occurring canine immune-mediated keratoconjunctivitis sicca (KCS). METHODS: A randomized, double-masked, placebo-controlled clinical study of 56-day duration was performed in dogs with naturally occurring immune-mediated KCS assigned to treatment with either topical twice-daily aqueous calcineurin inhibitor solution (SCY-641) or artificial tears (placebo) by the study administrator. Clinical examination and Schirmer tear tests (STT) were performed prior to therapy and at days 7, 14, 28, and 56 after initiation of treatment. RESULTS: Twenty dogs were enrolled in the study with ten receiving placebo and 10 receiving SCY-641 in one or both eyes. No adverse effects were noted with any treatment. There were no significant differences in mean STT values in dogs in group either at day 0 (prior to therapy) or after 7 days of treatment. At 14, 28, and 56 days after initiation of treatment, mean STT and increase in STT over baseline in dogs treated with SCY-641 were significantly higher than in dogs treated with placebo (P < 0.04). CONCLUSIONS: SCY-641 was well tolerated by dogs with naturally occurring KCS, and by 14 days after initiating therapy, dogs treated with SCY-641 had significantly higher STT than placebo-treated dogs. These preliminary results indicate that topical SCY-641, in a stable clear aqueous solution, is efficacious in a spontaneous model of KCS and warrants further evaluation as a treatment of immune-mediated KCS.

Breeding Efficiency for Salt Tolerance in Alfalfa.

Alfalfa (Medicago sativa L.), one of the most extensively grown forage crops, is sensitive to saline soils. We measured the breeding efficiency for increased salt tolerance in alfalfa by comparing lines selected from BC79S, CS, and SII populations with their unselected parental means for forage mass and associated changes in stem length, leaf-to-stem ratio (LSR), number of nodes per stem, crude protein (CP) content, and neutral detergent fiber (NDF) content. The overall forage mass in the non-salt-stressed test (9562 kg ha-1) was greater (p < 0.001) than under salt stress (5783 kg ha-1), with a 40% production advantage. In the non-salt-stressed test, the BC79S and CS lines averaged at a 4% lower production than their parents, while SII lines had on average a 9% greater production. Conversely, in the salt-stressed test, all lines showed a 20% overall greater seasonal production than their parents. Some selected lines produced more forage mass in both the non-stressed and salt-stressed tests than their parents. The stem length, LSR, node number, CP content, and NDF content of the selected lines varied with respect to non-stressed vs. stressed, but they tended not to differ greatly from their respective parental means under either non- or salt-stressed conditions. The selection protocol provided a universal increase in forage mass under salt-stressed field conditions of the selected lines. Furthermore, we identified lines with forage mass values greater than their parental means under non- and salt-stressed field conditions.