Programmable synthetic biomolecular condensates for cellular control

The formation of biomolecular condensates mediated by a coupling of associative and segregative phase transitions plays a critical role in controlling diverse cellular functions in nature. This has inspired the use of phase transitions to design synthetic systems. While design rules of phase transitions have been established for many synthetic intrinsically disordered proteins, most efforts have focused on investigating their phase behaviors in a test tube. Here, we present a rational engineering approach to program the formation and physical properties of synthetic condensates to achieve intended cellular functions. We demonstrate this approach through targeted plasmid sequestration and transcription regulation in bacteria and modulation of a protein circuit in mammalian cells. Our approach lays the foundation for engineering designer condensates for synthetic biology applications.

Protein nanowires with tunable functionality and programmable self-assembly using sequence-controlled synthesis

Advances in synthetic biology permit the genetic encoding of synthetic chemistries at monomeric precision, enabling the synthesis of programmable proteins with tunable properties. Bacterial pili serve as an attractive biomaterial for the development of engineered protein materials due to their ability to self-assemble into mechanically robust filaments. However, most biomaterials lack electronic functionality and atomic structures of putative conductive proteins are not known. Here, we engineer high electronic conductivity in pili produced by a genomically-recoded E. coli strain. Incorporation of tryptophan into pili increased conductivity of individual filaments >80-fold. Computationally-guided ordering of the pili into nanostructures increased conductivity 5-fold compared to unordered pili networks. Site-specific conjugation of pili with gold nanoparticles, facilitated by incorporating the nonstandard amino acid propargyloxy-phenylalanine, increased filament conductivity ~170-fold. This work demonstrates the sequence-defined production of highly-conductive protein nanowires and hybrid organic-inorganic biomaterials with genetically-programmable electronic functionalities not accessible in nature or through chemical-based synthesis.

Bacterial hairs called pili become highly-conductive electric wires upon addition of both natural and synthetic amino acids conjugated with gold nanoparticles. Here the authors use computationally-guided ordering further increasing their conductivity, thus yielding genetically-programmable materials.

Protein Phase Separation Arising from Intrinsic Disorder: First-Principles to Bespoke Applications

The phase separation of biomolecules has become the focus of intense research in the past decade, with a growing body of research implicating this phenomenon in essentially all biological functions, including but not limited to homeostasis, stress responses, gene regulation, cell differentiation, and disease. Excellent reviews have been published previously on the underlying physical basis of liquid-liquid phase separation (LLPS) of biological molecules (Nat. Phys. 2015, 11, 899-904) and LLPS as it occurs natively in physiology and disease (Science 2017, 357, eaaf4382; Biochemistry 2018, 57, 2479-2487; Chem. Rev. 2014, 114, 6844-6879). Here, we review how the theoretical physical basis of LLPS has been used to better understand the behavior of biomolecules that undergo LLPS in natural systems and how this understanding has also led to the development of novel synthetic systems that exhibit biomolecular phase separation, and technologies that exploit these phenomena. In part 1 of this Review, we explore the theory behind the phase separation of biomolecules and synthetic macromolecules and introduce a few notable phase-separating biomolecules. In part 2, we cover experimental and computational methods used to study phase-separating proteins and how these techniques have uncovered the mechanisms underlying phase separation in physiology and disease. Finally, in part 3, we cover the development and applications of engineered phase-separating polypeptides, ranging from control of their self-assembly to create defined supramolecular architectures to reprogramming biological processes using engineered IDPs that exhibit LLPS.

Packed red blood cell transfusion is an independent risk factor for necrotizing enterocolitis in premature infants

OBJECTIVE

To determine whether a temporal association exists between antecedent packed red blood cell (PRBC) transfusions and necrotizing enterocolitis (NEC) in premature infants.

STUDY DESIGN

This case-control study included inborn infants from a single center who developed NEC during a 2-year period. For every NEC infant, two matched controls from the same period were chosen based on gestational age and birth weight. Transfusion-related NEC was defined as antecedent PRBC transfusion within 48 h prior to the onset of any symptoms attributable to NEC. Bivariate analyses were used to compare baseline characteristics of all infants. To determine the raw odds ratio for the presence of exposure (transfusion) versus outcome (NEC), the hospital course (ages 6 to 63 days) of all study infants was divided into 48-h epochs; occurrence of transfusion and NEC was noted within each epoch. Generalized estimating equations were used to estimate the adjusted odds for developing NEC within an epoch with and without antecedent transfusion, controlling chronological age within infant as well as for gestational age, gender, feeding status in prior 48-h epoch and indicators of disease severity.

RESULT

There were 3652 48-h epochs and 557 transfusions among 49 NEC infants and 97 controls; 17 infants had transfusion-related NEC, yielding a raw odds ratio of 3.01 (P<0.001). The adjusted odds ratios were 2.97 (P=0.003) for transfusion and 2.76 (P=0.05) for feeding status in the prior 48-h epoch. Infants who were being fed in the 48-h period prior to transfusion were more than eight times more likely to develop NEC than infants who were neither fed nor transfused.

CONCLUSION

Antecedent PRBC transfusion appears to be an independent risk factor for developing NEC during the subsequent 48-h period.

Age differences in hemispheric activation to sensory condition

The effects of combinations of bright or dim light and noise levels on hand strength, fatigue, motor perseveration, and tapping rate were evaluated in 13 undergraduate and 13 elderly females. Increments in the intensity of sensory conditions produced opposite effects on grip strength at the left, as opposed to the right hand. Reliable asymmetry in hand strength (right > left) was observed in bright but not dim lighting in the younger group. In the elderly group, the extent of asymmetrical hand strength was related to the combination of light and noise intensity. Data suggest that increments in sensory conditions may differentially activate the cerebral hemispheres of the elderly and younger groups affecting grip strength. Results are discussed in relation to the hemiaging hypothesis.

Alternate forms of the AVLT: a procedure and test of form equivalency

The Rey Auditory Verbal Learning Test is frequently used in neuropsychological evaluation and research. However, its utility in the measurement of progressive change is limited by the availability of alternate and equivalent forms. Criteria were developed for word selection to generate new lists. Two alternate forms generated according to these criteria, as well as the original Key AVLT and alternate form, were administered to elderly Medical Center patients and undergraduate volunteers. All four AVLT forms yielded comparable mean recall scores, and alternate form reliability coefficients for each trial varied from.67 to.90. Conclusions from this study, though, must be made with caution as the sample size used was small.

Synchronous occurrence of parathyroid carcinoma and adenoma in an elderly woman

The simultaneous occurrence of parathyroid carcinoma and other pathologic conditions of the parathyroid on a sporadic basis is extremely rare. Parathyroid exploration in an otherwise healthy 78-year-old woman with no underlying risk factors revealed synchronous right upper parathyroid adenoma and left upper parathyroid carcinoma. The patient's modest hypercalcemia (11.5 to 12.3 mg/dl) was seemingly at variance with remarkable parathormone elevations of 30 to 70 times normal.

Effect of prolonged intra-arterial prostaglandin E1 infusion on canine arterial graft patency

This study examined the effect of long-term intra-arterial prostaglandin (PG) E1 infusion on the patency of canine femoral-artery grafts made of polytetrafluoroethylene and measuring 4 X 90 mm (diameter X length). An infusion catheter was placed proximal to one of the bilateral femoral-artery grafts and connected to a subcutaneously implanted infusion pump to continuously infuse PGE1 (1 ng/kg/min) in seven experimental dogs and vehicle alone in seven control dogs. Two-week graft patency was significantly higher in both infused (86%) and noninfused (100%) limbs of PGE1-treated dogs than in control dogs (29%). Although hind-limb blood flow was increased twofold to threefold by PGE1 infusion, graft patency did not improve. Prostaglandin E1 infusion did not significantly alter systemic platelet aggregation but did cause considerable hind-limb edema. Improved early graft patency, which did not persist beyond four weeks, was apparently related to systemic effects of local PGE1 infusion.

Effects of glucagon and prostacyclin in acute occlusive and postocclusive canine mesenteric ischemia

Effects of glucagon and prostacyclin (PGI2) were studied in anesthetized dogs during sequential occlusive and postocclusive mesenteric ischemia induced by 90 min of tourniquet stenosis of the superior mesenteric artery (SMA). After 30 min of SMA stenosis, glucagon (1 microgram/kg/min, n = 7), PGI2 (30 ng/kg/min, n = 7), or saline (1 ml/min, n = 3) was infused intravenously for 30 min, followed by 30 min of continued ischemia. SMA flow and distal SMA pressure ( SMAP ) decreased 76% with SMA stenosis (P less than 0.01). Ileal wall flow measured by radiolabeled microspheres decreased from 45 to 13 ml/min/100 g (P less than 0.01); mesenteric AV O2 difference ( AVDO2 ) increased from 5.1 to 10.1 ml/dl (P less than 0.01); and mesenteric O2 consumption (VO2) decreased by 48% (P less than 0.05). Glucagon infusion caused a further decrease in ileal wall flow, to 10 ml/min/100 g (P less than 0.05), and an increase in AVDO2 to 11 ml/dl (P less than 0.05), despite a 22% increase in cardiac output. PGI2 caused a similar decrease in ileal wall flow and an increase in AVDO2 , although these were not statistically significant. Saline infusion caused no change in measured variables. In the second phase of this study, SMA blood flow was restored by tourniquet release. After animals had stabilized for 30 min, a repeat 30-min drug infusion was studied. In this postocclusive period, persistent gut ischemia was indicated by a reduction in VO2 to 76% of original baseline, associated with a 50% decrease in both CO and SMAQ . Intravenous infusion of glucagon at this time increased SMAQ by 195% (P less than 0.05) and resulted in a return of VO2 to its original baseline level. PGI2 infusion caused a 21% increase in SMAQ and a 16% decrease in AVDO2 (NS), but had no significant effect on VO2. Glucagon was effective in the management of postocclusive mesenteric ischemia but appeared to have a detrimental effect on ileal blood flow in severe occlusive ischemia.

The effects of mesterolone, a male sex hormone in depressed patients (a double blind controlled study)

Based on computer EEG (CEEG) profiles, in high doses, antidepressant properties of mesterolone, a synthetic androgen, were predicted. In a double-blind placebo controlled study, the clinical effects of 300-450 mg daily mesterolone were investigated in 52 relatively young (age range 26-53 years, mean 42.7 years) male depressed outpatients. During 6 weeks of mesterolone treatment, there was a significant improvement of depressive symptomatology. However, since an improvement was also established during the placebo treatment, no statistically appreciable difference in the therapeutic effects of mesterolone was established compared to placebo. Mesterolone treatment significantly decreased both plasma testosterone and protein bound testosterone levels. Patients with high testosterone levels prior to treatment seem to have had more benefit from mesterolone treatment than patients with low testosterone levels. The degree of improvement weakly correlated to the decrease of testosterone levels during mesterolone treatment.

A family data base for the family oriented medical record

A family data base is defined along with the method for obtaining it. It can be used in its entirety to evaluate troubled families, or it can be abbreviated for intake and screening functions. Once complete, the data base is incorporated into the family oriented medical record, serving a purpose for the family analogous to that of the traditional history and physical examination for the individual. It provides for family medical and social information to be kept in one place, obviating the necessity of recording the information separately for each family member. The primary focus of the data base is psychosocial, but other problems, such as inherited or infectious disease in the family, are also included. This method has been used to teach concepts of family oriented care and to facilitate health care delivery in a variety of settings.

HZI systems for EEG parametrization and classification of psychotropic drugs

The EEG effects of twenty, clinically most frequently used psychotropic drugs and five placebos were studied in 75 male volunteers in five simultaneously designed basic studies. In each of the five studies single oral dosages of five drugs (well known representatives of neuroleptics, antidepressants, anxiolytics and psychostimulants, as well as placebos) were investigated in 15 subjects in a double-blind latin-square research design using the methods of the Quantitative Pharmaco-EEG. The results demonstrated that the therapeutically equivalent effective compounds also have similar effects on human EEG. With a classification rule, based on discriminant function 20, and with a classification rule, based on correlation statistics 19 of 25 compounds could be reclassified into correct clinical-therapeutic psychotropic drug groups. It is suggested that CEEG is an important tool in predicting and describing psychotropic properties of compounds, and should routinely be used in psychotropic drug development.