Specord 50 plus

BChl a and carotenoids were extracted and measured as described in Glaeser and Klug, 2005 [27 (link)]. Briefly, 1 mL samples of Rhodobacter cultures were harvested at 17,000× g for 5 min. Pellets were resuspended in 50 µL ddH₂O and mixed with 500 µL of acetone/methanol (7/2, v/v) by vortexing for 30 s. Samples were centrifuged at 17,000× g for 5 min, and the absorption of the supernatant was measured in a Specord 50 Plus spectrometer (Analytik Jena, Jena, Germany), using acetone/methanol (7/2, v/v) as a reference. The carotenoid and BChl a concentrations were calculated from the absorptions at 484 and 770 nm, respectively, with extinction coefficients of 128 mM⁻¹·cm⁻¹ for carotenoids [44 (link)] and 76 mM⁻¹·cm⁻¹ for BChl a [45 ]. Concentrations were normalized to the OD₆₆₀.

UV‐Visible absorption of COCP was characterized with a UV spectrophotometer (SPECORD^® 50 PLUS, Analytik Jena). As much as 1.0 mg/ml of polysaccharide solution was prepared with ultrapure water and then employed to conduct the UV‐visible spectroscopy observation in the wavelength range of 200–800 nm, by using ultrapure water as the background.
Fourier transform infrared (FT‐IR) spectroscopy of COCP was monitored with a FT‐IR spectrophotometer (Nicolet iS50, Thermo Scientific). The dried polysaccharide sample was ground with potassium bromide (KBr) and then pressed into slices, and then it was subjected to FT‐IR spectrum analysis in the wavenumber range of 4000–400 cm^‐1 using 32 scans with a resolution of 4 cm^‐1.

The coloration of the PTS was documented by photography, determined with a spectrophotometer (Specord 50 Plus; Analytik Jena AG, Jena, Germany) and analyzed with WinASPECT PLUS software (Analytik Jena AG, Jena, Germany).

APGD-MS experiments were performed with a homemade ion source of APGD (Figure 6) coupled with a triple quadrupole mass spectrometer (Agilent Technologies, Santa Clara, CA, USA). The APGD ion source consisted of a quartz tube, titanium tube anode, and tungsten cathode. The APGD-MS experiments were carried out with the gas flow rate in the range of 100–600 mL/min, discharge voltage in the range of 765–1005 V, interelectrode gap distance in the range of 2–8 mm, and distance between the anode orifice and the MS inlet ranging from 3–15 mm. The basic parameters of MS were performed with m/z in the range of 10–500 and collision energy range in the range of 1–20 eV. The collision gas was nitrogen. The catalytic ability of PPO measured the absorbance at 475 nm by a UV–Vis spectrophotometer (SPECORD 50 PLUS, Analytik Jena, GA, Jena, Germany). The ESI-Q-TOF-MS (Agilent Technologies, Santa Clara, CA, USA) was determined to perform the experiments.

Steady-state kinetic constants (K_m and k_cat) were determined by measuring substrate hydrolysis under initial rate conditions and using the Hanes–Woolf linearization of the Michaelis–Menten equation (50 ). Kinetic experiments were performed by following the hydrolysis of each substrate at 30°C in 50 mM HEPES buffer pH 7.5, 50 mM Na₂CO₃. The reactions were performed in a total volume of 500 μL at 30°C. BSA (20 μg/mL) was added to diluted solutions of beta-lactamase in order to prevent enzyme denaturation. The data were collected with a Specord 50 PLUS spectrophotometer (Analytik Jena). Each kinetic value is the mean of three different measurements.

Scanning
electron microscopy (SEM) images
were captured using a FEI NOVA NanoSEM 230 at 5 kV. Transmission electron
microscopy (TEM) images were captured using a JEOL JEM-2100 microscope.
The ζ-potential and hydrodynamic radius were measured using
a Malvern Zetasizer Nano ZS system. Protein quantification, enzymatic
activity assays, and OD₆₀₀ determination were carried out
using a Synergy HTX Absorbance microplate reader and a Synergy H1M
Fluorescence microplate reader. A spectrophotometer Specord 50/plus
(Analytik Jena, Germany) was employed to monitor the U-MSNP and M-MSNP
activity for 14 days. Optical videos were recorded using an inverted
optical microscope (Leica DMi8) equipped with a 63× water objective.
Fluorescence images of live/dead assay were acquired using an inverted
optical microscope (Leica DMI3000B), coupled with a 10×, 20×,
40×, and 63× objectives, along with a Leica digital camera
DFC3000G with LAS V4.5 software. The videos were analyzed using Python-based
code. Growth curves of planktonic E. coli were performed using a SPARK Multimode microplate reader (Tecan).
Continuous biofilms were imaged using a Zeiss LSM 800 confocal laser
scanning microscope (CLSM) with a 20×/0.8 air objective. FIJI
and COMSTAT2 software were used for biofilm biomass quantification.
Origin 2018, Microsoft Excel Professional, and ImageJ were employed
for the analysis of the experimental data.