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Understanding how bacteria grow and divide requires insight into both the molecular-level dynamics of ultrastructure and the chemistry of the constituent components. Atomic force microscopy (AFM) can provide near molecular resolution images of biological systems but typically provides limited chemical information. Conversely, while super-resolution optical microscopy allows localization of particular molecules and chemistries, information on the molecular context is difficult to obtain. Here, we combine these approaches into STORMForce (stochastic optical reconstruction with atomic force microscopy) and the complementary SIMForce (structured illumination with atomic force microscopy), to map the synthesis of the bacterial cell wall structural macromolecule, peptidoglycan, during growth and division in the rod-shaped bacterium Bacillus subtilis. Using "clickable" d-amino acid incorporation, we fluorescently label and spatially localize a short and controlled period of peptidoglycan synthesis and correlate this information with high-resolution AFM of the resulting architecture. During division, septal synthesis occurs across its developing surface, suggesting a two-stage process with incorporation at the leading edge and with considerable in-filling behind. During growth, the elongation of the rod occurs through bands of synthesis, spaced by ∼300 nm, and corresponds to denser regions of the internal cell wall as revealed by AFM. Combining super-resolution optics and AFM can provide insights into the synthesis processes that produce the complex architectures of bacterial structural biopolymers.

Understanding how bacteria grow and divide requires insight into both the molecular-level dynamics of ultrastructure and the chemistry of the constituent components. Atomic force microscopy (AFM) can provide near molecular resolution images of biological systems but typically provides limited chemical information. Conversely, while super-resolution optical microscopy allows localization of particular molecules and chemistries, information on the molecular context is difficult to obtain. Here, we combine these approaches into STORMForce (stochastic optical reconstruction with atomic force microscopy) and the complementary SIMForce (structured illumination with atomic force microscopy), to map the synthesis of the bacterial cell wall structural macromolecule, peptidoglycan, during growth and division in the rod-shaped bacterium Bacillus subtilis. Using “clickable” d-amino acid incorporation, we fluorescently label and spatially localize a short and controlled period of peptidoglycan synthesis and correlate this information with high-resolution AFM of the resulting architecture. During division, septal synthesis occurs across its developing surface, suggesting a two-stage process with incorporation at the leading edge and with considerable in-filling behind. During growth, the elongation of the rod occurs through bands of synthesis, spaced by ∼300 nm, and corresponds to denser regions of the internal cell wall as revealed by AFM. Combining super-resolution optics and AFM can provide insights into the synthesis processes that produce the complex architectures of bacterial structural biopolymers.

The bacterial cell wall is essential for viability, but despite its ability to withstand internal turgor must remain dynamic to permit growth and division. Peptidoglycan is the major cell wall structural polymer, whose synthesis requires multiple interacting components. The human pathogen Staphylococcus aureus is a prolate spheroid that divides in three orthogonal planes. Here, we have integrated cellular morphology during division with molecular level resolution imaging of peptidoglycan synthesis and the components responsible. Synthesis occurs across the developing septal surface in a diffuse pattern, a necessity of the observed septal geometry, that is matched by variegated division component distribution. Synthesis continues after septal annulus completion, where the core division component FtsZ remains. The novel molecular level information requires re-evaluation of the growth and division processes leading to a new conceptual model, whereby the cell cycle is expedited by a set of functionally connected but not regularly distributed components.

Different extracts of the edible seaweed, Ascophyllum nodosum, were compared for their ability to inhibit α-amylase and effectiveness was linked to phenol and apparent phlorotannin contents. After solid phase extraction, phenolic-enriched extracts retained potent α-amylase inhibition [IC50 ~ 0.05 µg GAE/mL], whereas phlorotannin-rich sub-fractions were threefold less potent. Potency could be restored by re-addition of the wash fraction suggesting synergy between tannin and non-tannin components. The phenolic-rich extract and the phlorotannin-rich fraction inhibited α-glucosidase equally effectively (IC50 ~ 10 µg GAE/mL). Co-incubation of the tannin-rich fraction with acarbose reduced the concentration of acarbose required for effective inhibition of both amylase and glucosidase. That pre-incubation of amylase with the tannin-rich fraction markedly improved but the addition of BSA reduced inhibitory effectiveness suggested that phlorotannins inhibit amylase, but not glucosidase, through a protein-binding mechanism. The use of phlorotannins in combination with acarbose for postprandial glycemic control in type-2 diabetics is discussed.

Aims: Carbon monoxide (CO) delivered to cells and tissues by CO-releasing molecules (CO-RMs) has beneficial and toxic effects not mimicked by CO gas. The metal carbonyl Ru(CO)3Cl(glycinate) (CORM-3) is a novel, potent antimicrobial agent. Here, we established its mode of action. Results: CORM-3 inhibits respiration in several bacterial and yeast pathogens. In anoxic Escherichia coli suspensions, CORM-3 first stimulates, then inhibits respiration, but much higher concentrations of CORM-3 than of a classic protonophore are required for stimulation. Proton translocation measurements (H+/O quotients, i.e., H+ extrusion on pulsing anaerobic cells with O2) show that respiratory stimulation cannot be attributed to true “uncoupling,” that is, dissipation of the protonmotive force, or to direct stimulation of oxidase activity. Our data are consistent with CORM-3 facilitating the electrogenic transmembrane movement of K+ (or Na+), causing a stimulation of respiration and H+ pumping to compensate for the transient drop in membrane potential (ΔΨ). The effects on respiration are not mimicked by CO gas or control Ru compounds that do not release CO. Inhibition of respiration and loss of bacterial viability elicited by CORM-3 are reversible by white light, unambiguously identifying heme-containing oxidase(s) as target(s). Innovation: This is the most complete study to date of the antimicrobial action of a CO-RM. Noteworthy are the demonstration of respiratory stimulation, electrogenic ion transport, and photosensitive activity, establishing terminal oxidases and ion transport as primary targets. Conclusion: CORM-3 has multifaceted effects: increased membrane permeability, inhibition of terminal oxidases, and perhaps other unidentified mechanisms underlie its effectiveness in tackling microbial pathogenesis. Antioxid. Redox Signal. 19, 497–509.

Phenolic-rich extracts from four edible marine macroalgae commonly found in UK waters were tested for their potential biological effects towards cultured colon cancer cells and for their ability to inhibit digestive enzymes to achieve potential anti-diabetic effects. Extracts from Palmaria, Ascophyllum and Alaria, but not Ulva, gave reasonable recoveries of phenolics and inhibited the proliferation of colon cancer cells in a dose-responsive manner. Alaria extracts were more effective than Palmaria or Ascophyllum extracts, but Palmaria and Ascophyllum would provide greater amounts of phenolics per gram intake. Extracts from Palmaria, Ascophyllum and Alaria all inhibited α-amylase activity to some extent, but Ascophyllum extracts were very effective with an IC50 of ∼0.1 μg/ml GAE. The Ascophyllum extracts also inhibited α-glucosidase, the other key enzyme involved in starch digestion and blood glucose regulation, at low levels (e.g. IC50 ∼20 μg/ml GAE). After fractionation on Sephadex LH-20, the inhibitory activity from Ascophyllum was concentrated in the fraction which, from mass spectrometric evidence, was enriched in phlorotannins. These components have the capacity to inhibit α-amylase and α-glucosidase activities at μM levels, which are easily achievable in the gut. This may explain the anti-diabetic properties associated with algal extracts and algal phenolics in various in vivo studies.

Using family stress theory, we examined the influence of family and health stress, level of coping, and internal health locus of control upon the life contentment of individuals diagnosed with bipolar disorder (BPD) who were either adherent or nonadherent to their medication regimens. A survey-interview design was used with a sample of 100 individuals diagnosed with BPD; 50 participants were adherent to their medication and 50 were considered nonadherent. The results indicated that the adherent group had fewer health problems and more resources for coping with stress, possessed a stronger belief that their own behaviors controlled their health status, and had higher life contentment compared to nonadherent participants. For the participants in this study, internal health locus of control had the greatest total effect on life contentment followed by family coping. Implications included the need to comprehensively assess each individual regarding the multiple factors in one's life that influence an effective treatment regimen.

The issue of medication compliance is a multidimensional phenomenon that rests not only with the patient, but also with the interactions of caregivers. Study results revealed that nurses and patients generally perceive estimated frequency of medication compliance to be similar, although increased length of time as a psychiatric nurse was associated with nurses perceiving patients as being less compliant. Reasons given by patients and nurses for medication noncompliance differed. Patients' responses were characterized by being more concrete and varied in nature than those of the nurse.