Macrocyclic lactams as potent Hsp90 inhibitors with excellent tumor exposure and extended biomarker activity

A novel series of macrocyclic ortho-aminobenzamide Hsp90 inhibitors is reported. In continuation of our research in this area, macrocyclic amides and lactams were explored to reduce the risk of hERG liabilities. This effort culminated in the discovery of compound 38, which showed a favorable in vitro profile, and efficiently suppressed proliferation of several relevant cell lines. This compound showed prolonged Hsp90-inhibitory activity at least 24 h post-administration, consistent with elevated and prolonged exposure in the tumor.     

Potato-associated arbuscular mycorrhizal fungal communities in the Peruvian Andes

The world's fourth largest food crop, potato, originates in the Andes. Here, the community composition of arbuscular mycorrhizal fungi (AMF) associated with potato in Andean ecosystems is described for the first time. AMF were studied in potato roots and rhizosphere soil at four different altitudes from 2,658 to 4,075 m above mean sea level (mamsl) and in three plant growth stages (emergence, flowering, and senescence). AMF species were distinguished by sequencing an approx. 1,500 bp nuclear rDNA region. Twenty species of AMF were identified, of which 12 came from potato roots and 15 from rhizosphere soil. Seven species were found in both roots and soil. Interestingly, altitude affected species composition with the highest altitude exhibiting the greatest species diversity. The three most common colonizers of potato roots detected were Funneliformis mosseae, an unknown Claroideoglomus sp., and Rhizophagus irregularis. Notably, the potato-associated AMF diversity observed in this Andean region is much higher than that reported for potato in other ecosystems. Potato plants were colonized by diverse species from 8 of the 11 Glomeromycota families. Identification of the AMF species is important for their potential use in sustainable management practices to improve potato production in the Andean region.     

Correlates of attendance at community engagement meetings held in advance of bio-behavioral research studies: A longitudinal,sociocentric social network study in rural Uganda

BackgroundCommunity engagement is central to the conduct of health-related research studies as a way to determine priorities, inform study design and implementation, increase recruitment and retention, build relationships, and ensure that research meets the goals of the community. Community sensitization meetings, a form of community engagement, are often held prior to the initiation of research studies to provide information about upcoming study activities and resolve concerns in consultation with potential participants. This study estimated demographic, health, economic, and social network correlates of attendance at community sensitization meetings held in advance of a whole-population, combined behavioral, and biomedical research study in rural Uganda.Methods and findingsResearch assistants collected survey data from 1,630 adults participating in an ongoing sociocentric social network cohort study conducted in a rural region of southwestern Uganda. These community survey data, collected between 2016 and 2018, were linked to attendance logs from community sensitization meetings held in 2018 and 2019 before the subsequent community survey and community health fair. Of all participants, 264 (16%) attended a community sensitization meeting before the community survey, 464 (28%) attended a meeting before the community health fair, 558 (34%) attended a meeting before either study activity (survey or health fair), and 170 (10%) attended a meeting before both study activities (survey and health fair). Using multivariable Poisson regression models, we estimated correlates of attendance at community sensitization meetings. Attendance was more likely among study participants who were women (adjusted relative risk [ARR]_{health fair} = 1.71, 95% confidence interval [CI], 1.32 to 2.21, p < 0.001), older age (ARR_survey = 1.02 per year, 95% CI, 1.01 to 1.02, p < 0.001; ARR_{health fair} = 1.02 per year, 95% CI, 1.01 to 1.02, p < 0.001), married (ARR_survey = 1.74, 95% CI, 1.29 to 2.35, p < 0.001; ARR_{health fair} = 1.41, 95% CI, 1.13 to 1.76, p = 0.002), and members of more community groups (ARR_survey = 1.26 per group, 95% CI, 1.10 to 1.44, p = 0.001; ARR_{health fair} = 1.26 per group, 95% CI, 1.12 to 1.43, p < 0.001). Attendance was less likely among study participants who lived farther from meeting locations (ARR_survey = 0.54 per kilometer, 95% CI, 0.30 to 0.97, p = 0.041; ARR_{health fair} = 0.57 per kilometer, 95% CI, 0.38 to 0.86, p = 0.007). Leveraging the cohort’s sociocentric design, social network analyses suggested that information conveyed during community sensitization meetings could reach a broader group of potential study participants through attendees’ social network and household connections. Study limitations include lack of detailed data on reasons for attendance/nonattendance at community sensitization meetings; achieving a representative sample of community members was not an explicit aim of the study; and generalizability may not extend beyond this study setting.ConclusionsIn this longitudinal, sociocentric social network study conducted in rural Uganda, we observed that older age, female sex, being married, membership in more community groups, and geographical proximity to meeting locations were correlated with attendance at community sensitization meetings held in advance of bio-behavioral research activities. Information conveyed during meetings could have reached a broader portion of the population through attendees’ social network and household connections. To ensure broader input and potentially increase participation in health-related research studies, the dissemination of research-related information through community sensitization meetings may need to target members of underrepresented groups.

In a social network cohort study, Emily Satinsky and colleagues estimate demographic, health, economic and social network factor associated with attendance at community sensitization meetings held in advance of participation in health-related research studies in rural Uganda.     

High gametocyte complexity and mosquito infectivity of Plasmodium falciparum in the Gambia

The purpose of this work was to determine the infectivity to mosquitoes of genetically diverse Plasmodium falciparum clones seen in natural infections in the Gambia. Two principal questions were addressed: (i) how infectious are gametocytes of sub-patent infections, particularly at the end of the dry season; and (ii) are all clones in multiclonal infections equally capable of infecting mosquitoes? The work was carried out with two cohorts of infected individuals. Firstly, a group of 31 P. falciparum-infected people were recruited in the middle of the dry season (May, 2003), then examined for P. falciparum at the beginning (August 2003) and middle (October, 2003) of the transmission season. On each occasion, we examined the genotypes of asexual forms and gametocytes by PCR and RT-PCR, as well as their infectivity to Anopheles gambiae using membrane feeds. One individual gave rise to infected mosquitoes in May, and two in August. Different gametocyte genotypes co-existed in the same infection and fluctuated over time. The mean multiplicity of infection was 1.4, 1.7 and 1.5 clones in May, August and October, respectively. Second, a group of patients undergoing drug-treatment during August 2003 was tested for asexual and gametocyte genotypes and their infectivity to mosquitoes. Forty-three out of 100 feeds produced infections. The genetic complexity of the parasites in mosquitoes was sometimes greater than that detectable in the blood on which the mosquitoes had fed. This suggested that gametocytes of clones existing in the blood below PCR detection limits at the time of the feed were at least as infectious to the mosquitoes as the more abundant clones. These findings emphasise the crucial role of gametocyte complexity and infectivity in generating the remarkable diversity of P. falciparum genotypes seen in infected people, even in an area of seasonal transmission.     

Functional analysis of the triplex proteins (VP19C and VP23) of herpes simplex virus type 1

The triplex of herpesvirus capsids is a unique structural element. In herpes simplex virus type 1 (HSV-1), one molecule of VP19C and two of VP23 form a three-pronged structure that acts to stabilize the capsid shell through interactions with adjacent VP5 molecules. The interaction between VP19C and VP23 was inferred by yeast cryoelectron microscopy studies and subsequently confirmed by the two-hybrid assay. In order to define the functional domains of VP19C and VP23, a Tn7-based transposon was used to randomly insert 15 bp into the coding regions of these two proteins. The mutants were initially screened for interaction in the yeast two-hybrid assay to identify the domains important for triplex formation. Using genetic complementation assays in HSV-1-infected cells, the domains of each protein required for virus replication were similarly uncovered. The same mutations that abolish interaction between these two proteins in the yeast two-hybrid assay similarly failed to complement the growth of the VP23- and VP19C-null mutant viruses in the genetic complementation assay. Some of these mutants were transferred into recombinant baculoviruses to analyze the effect of the mutations on herpesvirus capsid assembly in insect cells. The mutations that abolished the interaction in the yeast two-hybrid assay also abolished capsid assembly in insect cells. The outcome of these experiments showed that insertions in at least four regions and especially the amino terminus of VP23 abolished function, whereas the amino terminus of VP19C can tolerate transposon insertions. A novel finding of these studies was the ability to assemble herpesvirus capsids in insect cells using VP5 and VP19C that contained a histidine handle at their amino terminus.     

Cohesins and condensins orchestrate the 4D dynamics of yeast chromosomes during the cell cycle

Duplication and segregation of chromosomes involves dynamic reorganization of their internal structure by conserved architectural proteins, including the structural maintenance of chromosomes (SMC) complexes cohesin and condensin. Despite active investigation of the roles of these factors, a genome‐wide view of dynamic chromosome architecture at both small and large scale during cell division is still missing. Here, we report the first comprehensive 4D analysis of the higher‐order organization of the Saccharomyces cerevisiae genome throughout the cell cycle and investigate the roles of SMC complexes in controlling structural transitions. During replication, cohesion establishment promotes numerous long‐range intra‐chromosomal contacts and correlates with the individualization of chromosomes, which culminates at metaphase. In anaphase, mitotic chromosomes are abruptly reorganized depending on mechanical forces exerted by the mitotic spindle. Formation of a condensin‐dependent loop bridging the centromere cluster with the rDNA loci suggests that condensin‐mediated forces may also directly facilitate segregation. This work therefore comprehensively recapitulates cell cycle‐dependent chromosome dynamics in a unicellular eukaryote, but also unveils new features of chromosome structural reorganization during highly conserved stages of cell division.     

Estimating the rate of evolution of the rate of molecular evolution

A simple model for the evolution of the rate of molecular evolution is presented. With a Bayesian approach, this model can serve as the basis for estimating dates of important evolutionary events even in the absence of the assumption of constant rates among evolutionary lineages. The method can be used in conjunction with any of the widely used models for nucleotide substitution or amino acid replacement. It is illustrated by analyzing a data set of rbcL protein sequences.      

Forty-Day Fever: An Epidemic of Cytomegalovirus Disease in a Renal Transplant Population

An epidemic of cytomegalovirus disease (CMV) occurred in 38 percent of 34 renal transplant recipients during an 18-month period. A characteristic clinical pattern was noted: 40 days following transplantation, daily fevers recurred for periods of four to six weeks. This fever in conjunction with a diffuse interstitial pneumonitis and impaired hepatic and renal function constituted a diagnostic tetrad. Of all the laboratory techniques, throat and urine cultures were the most consistent in confirming the diagnosis.Analysis of the epidemic implicated the communal hemodialysis unit as the source of exposure to the virus. CMV was not seen in the first 86 patients who received transplants in the program, but with increasing use of hemodialysis, the percentage of patients with positive serologic reaction for CMV increased dramatically.     

The effect of starvation on energy turnover and protein metabolism in Ophiocephalus punctatus bloch

1. At 20°C, fish starved for various durations took less food than unstarved fish. At 28°C, 20-day starved fish alone consumed more food.
2. The maximum feeding was during the second ten days at 28°C but in the first ten days at 20°C.
3. Absorption efficiency was unaffected by temperature and starvation.
4. Absorption rate reflected feeding rate.
5. At 28°C the conversion efficiency was high for the ten-day starved fish but at 20°C the 30-day starved fish showe high conversion efficiency.
6. Conversion rate is governed not only by feeding rate but also by conversion efficiency.
7. At 28°C the 20-day starved fish alone compensated for loss of energy, total and protein nitrogen. At 20°C the loss was compensated for by all fish.

     

Phosphorylated HSP27 essential for acetylcholine-induced association of RhoA with PKCalpha

Reorganization of the cytoskeleton and association of contractile proteins are important steps in modulating smooth muscle contraction. Heat shock protein (HSP) 27 has significant effects on actin cytoskeletal reorganization during smooth muscle contraction. We investigated the role of phosphorylated HSP27 in modulating acetylcholine-induced sustained contraction of smooth muscle cells from the rabbit colon by transfecting smooth muscle cells with phosphomimic (3D) or nonphosphomimic (3G) HSP27. In 3G cells, the initial peak contractile response at 30 s was inhibited by 25% (24.0 +/- 4.5% decrease in cell length, n = 4). The sustained contraction was greatly inhibited by 75% [9.3 +/-.9% decreases in cell length (n = 4)]. Furthermore, in 3D cells, translocation of both PKCalpha and of RhoA was greatly enhanced and resulted in a greater association of PKCalpha-RhoA in the membrane fraction. In 3G transfected cells, PKCalpha and RhoA failed to translocate in response to stimulation with acetylcholine, resulting in an inhibition of association of PKCalpha-RhoA in the membrane fraction. Studies using GST-RhoA fusion protein indicate that there is a direct association of RhoA with PKCalpha and with HSP27. The results suggest that phosphorylated HSP27 plays a crucial role in the maintenance of association of PKCalpha-RhoA in the membrane fraction and in the maintenance of acetylcholine-induced sustained contraction.