Characterization and Antioxidant Activity of the Polysaccharide Hydrolysate from Lactobacillus plantarum LPC-1 and Their Effect on Spinach (Spinach oleracea L.) Growth.

This study presents a comparison between two hydrolysis systems (MnO2/H2O2 and ascorbic acid (VC)/H2O2) for the depolymerization of exopolysaccharide (EPS) from Lactobacillus plantarum LPC-1. Response surface methodology (RSM) was used to optimize these two degradation systems, resulting in two H2O2-free degradation products, MEPS (MnO2/H2O2-treated EPS) and VEPS (VC/H2O2-treated EPS), where H2O2 residues in the final products and their antioxidant activity were considered vital points. The relationship between the structural variations of two degraded polysaccharides and their antioxidant activity was characterized. Physicochemical tests showed that H2O2 had a notable impact on determining the total and reducing sugars in the polysaccharides, and both degradation systems efficiently eliminated this effect. After optimization, the average molecular weight of EPS was reduced from 265.75 kDa to 135.41 kDa (MEPS) and 113.11 kDa (VEPS), improving its antioxidant properties. Characterization results showed that the two hydrolysis products had similar major functional groups and monosaccharide composition as EPS. The crystal structure, main chain length, and branched chain number were crucial factors affecting the biological activity of polysaccharides. In pot testing, two degraded polysaccharides improved spinach quality more than EPS due to their lower molecular weights, suggesting the advantages of low-molecular-weight polysaccharides. In summary, these two degradation techniques offer valuable insights for further expanding the utilization of microbial resources.

Preparation of polysaccharide-conjugated selenium nanoparticles from spent mushroom substrates and their growth-promoting effect on rice seedlings.

Selenium nanoparticles (SeNPs) have gained significant attention in the agricultural field due to their favorable bioavailability and low toxicity, making them a highly researched subject. In this study, crude polysaccharides from spent mushroom substrate of Agrocybe aegerita (AaPs) were extracted for preparing the polysaccharide­selenium-nanoparticles (AaPs-SeNPs) by ascorbic acid reduction method. The structure of AaPs-SeNPs was analyzed and their growth-promoting effects on rice seedlings were studied by adopting different application methods. The results revealed that AaPs-SeNPs exhibited improved free radical scavenging ability, with a lower half-maximal inhibitory concentrations compared to AaPs. Rice seedlings treated with AaPs-SeNPs showed significant enhancements in growth characteristics when compared to AaPs treatment, and foliar application exhibited a better growth-promoting effect compared to root application. Moreover, the growth performance and antioxidant enzyme activities of rice seedlings were enhanced by the addition of AaPs-SeNPs, and the absorption efficiency of essential nutrients such as N/P/K and Fe/Zn/Mn was also improved at appropriate concentrations, which could be one of the key factors contributing to the improved growth performance of plants. This study provides new aspects for the utilization of SMS, and also offers new insights from the perspective of nutrient absorption on how polysaccharide-conjugated selenium nanoparticles enhance crop growth.

Aqua-bis-(4-chloro-2-hy-droxy-benzoato-κO)(1,10-phenanthroline-κN,N')zinc(II).

In the title compound, [Zn(C(7)H(4)ClO(3))(2)(C(12)H(8)N(2))(H(2)O)], the Zn(II) cation is coordinated by two 4-chloro-2-salicylate anions, one 1,10-phenanthroline ligand and one water mol-ecule in a square-pyramidal coordination geometry; the Zn cation lies 0.4591 (11) Šfrom the basal plane. The benzene rings of the anions are involved in π-π stacking. The centroid-centroid distance between parallel benzene rings of adjacent mol-ecules is 3.9017 (17) Å, and the centroid-centroid distance between benzene and pyridine rings of adjacent mol-ecules is 3.584 (2) Å. Intra-molecular O-H⋯O hydrogen bonding is present.

Poly[[tris-(µ(3)-2-oxidopyridinium-3-carboxyl-ato)manganese(II)sodium(I)] monohydrate].

In the crystal structure of the title compound, {[MnNa(C(6)H(4)NO(3))(3)]·H(2)O}(n), the Mn(II) cation is located on a threefold rotation axis and is chelated by three 2-oxidopyridinium-3-carboxyl-ate (opc) anions in an octa-hedal coordination. The Na(I) cation is located on a threefold rotation axis and is surrounded by six O atoms from three opc anions. The opc anions link the Mn and Na cations, forming a three-dimensional polymeric structure. The uncoordinated water mol-ecule, located on a threefold rotation axis, is equally disordered over two sites. The three-dimensional network is consolidated by N-H⋯O hydrogen bonds.

Bis(µ-imino-diacetato)bis-[(2,2'-diamino-4,4'-bi-1,3-thia-zole)lead(II)] tetra-hydrate.

In the crystal structure of the title compound, [Pb(2)(C(4)H(5)NO(4))(2)(C(6)H(6)N(4)S(2))(2)]·4H(2)O, the dinuclear Pb(II) complex mol-ecule is centrosymmetric. The Pb atom is chelated by a tridentate imino-diacetate anion (IDA) and a diamino-bithia-zole (DABT) ligand, while a carboxyl-ate O atom from an adjacent IDA anion further bridges the Pb atom with a longer Pb-O bond [2.892 (3) Å]. The lone-pair electrons of the Pb atom occupy an axial site in the Ψ-penta-gonal-bipyramidal coordination polyhedron. The IDA anion displays a facial configuration: its chelating five-membered rings assume an envelope configuration. Within the DABT ligand, the two thia-zole rings are twisted relative to each other, making a dihedral angle of 9.51 (17)°. Extensive N-H⋯O, O-H⋯O and weak C-H⋯O hydrogen bonding helps to stabilize the crystal structure.

Bis(µ-4-chloro-2-oxidobenzoato)bis-[(1,10-phenanthroline)copper(II)] dihydrate.

The structure of the the title compound, [Cu(2)(C(7)H(3)ClO(3))(2)(C(12)H(8)N(2))(2)]·2H(2)O, consists of a dimeric unit involving a planar Cu(2)O(2) group arranged around an inversion center. The coordination sphere of the Cu(II) atom can be described as an elongated distorted square pyramid where the basal plane is formed by the two N atoms of the 1,10-phenanthroline mol-ecule and the two O atoms of the hydroxy-chloro-benzoate (hcbe) anion. The long apical Cu-O distance of 2.569 (2) Šinvolves the O atom of a symmetry-related hcbe anion, building up the dinuclear unit. Each dinuclear unit is connected through O-H⋯O hydrogen bonds involving two water mol-ecules, resulting in an R(4) (2)(8) graph-set motif and building up an infinite chain parallel to (10). C-H⋯O inter-actions further stabilize the chain.

[(E)-But-2-enoato-κO]chlorido(2,2'-diamino-4,4'-bi-1,3-thia-zole-κN,N)zinc(II) monohydrate.

In the title compound, [Zn(C(4)H(5)O(2))Cl(C(6)H(6)N(4)S(2))]·H(2)O, the Zn(II) cation is coordinated by a bidentate diamino-bithia-zole (DABT) ligand, a but-2-enoate anion and a Cl(-) anion in a distorted tetra-hedral geometry. Within the DABT ligand, the two thia-zole rings are twisted to each other at a dihedral angle of 4.38 (10)°. An intra-molecular N-H⋯O inter-action occurs. The centroid-centroid distance of 3.6650 (17) Šand partially overlapped arrangement between nearly parallel thia-zole rings of adjacent complexes indicate the existence of π-π stacking in the crystal structure. Extensive O-H⋯Cl, O-H⋯O, N-H⋯Cl and N-H⋯O hydrogen bonding helps to stabilize the crystal structure.

Bis(µ-2,4-dihy-droxy-benzoato-κO:O')bis-[aqua-(2,4-dihy-droxy-benzoato-κO)(1,10-phenanthroline-κN,N')cadmium(II)].

In the title centrosymmetric dimeric Cd(II) complex, [Cd(2)(C(7)H(5)O(4))(4)(C(12)H(8)N(2))(2)(H(2)O)(2)], the Cd(II) cation is coord-inated by a bidentate phenanthroline (phen) ligand, three dihy-droxy-benzoate (dhba) anions and one water mol-ecule in a distorted CdN(2)O(4) octa-hedral geometry. Among the dhba anions, two anions bridge two Cd(II) cations to form the dimeric complex with significant different Cd-O bond distances of 2.2215 (19) and 2.406 (2) Å. The centroid-centroid distance of 3.4615 (19) Šbetween two nearly parallel benzene rings of the dhba and phen ligands coordinating to the same Cd(II) cation indicates the existence of intra-molecular π-π stacking in the complex. Extensive O-H⋯O hydrogen bonding and inter-molecular weak C-H⋯O hydrogen bonding help to stabilize the crystal structure. One hy-droxy group of the monodentate dhba ligand is disordered over two sites with a site-occupancy ratio of 0.9:0.1.

catena-Poly[[diaqua-bis-(isoquinoline-κN)cobalt(II)]-µ-succinato-κO:O].

In the title compound, [Co(C(4)H(4)O(4))(C(9)H(7)N)(2)(H(2)O)(2)](n), the Co(II) cation, located on an inversion center, is coordinated by two succinate anions, two isoquinoline ligands and two water mol-ecules in a distorted octa-hedral geometry. The succinate anion, located across another inversion center, bridges the Co cations, forming polymeric chains running along the b axis. The partially overlapped arrangement of parallel isoquinoline ring systems of adjacent polymeric chains and the shorter face-to-face distance of 3.402 (6) Šindicates the existence of weak π-π stacking in the crystal structure. Classical intra- and inter-molecular O-H⋯O hydrogen bonding and weak non-classical inter-molecular C-H⋯O hydrogen bonding help to stabilize the crystal structure.

Dichloridobis(isoquinoline-κN)zinc(II).

In the title compound, [ZnCl(2)(C(9)H(7)N)(2)], the Zn(II) cation is coordinated by two Cl(-) anions and two isoquinoline ligands in a distorted ZnCl(2)N(2) tetra-hedral geometry; the two isoquinoline ring systems are twisted with respect to each other at a dihedral angle of 45.72 (8)°. The parallel isoqiunoline ring systems of adjacent mol-ecules are partially overlapped, with the shorter face-to-face distance of 3.438 (19) Šindicating the existence of weak π-π stacking in the crystal structure.

Tetra-kis(µ(2)-phenyl-acetato-κO:O')bis-[(isoquinoline-κN)copper(II)].

In the title centrosymmetric binuclear Cu(II) complex, [Cu(2)(C(8)H(7)O(2))(4)(C(9)H(7)N)(2)], the two Cu cations are bridged by four carboxyl-ate groups of the phenyl-acetate anions; each Cu cation is further coordinated by an isoquinoline ligand to complete the distorted CuO(4)N square-pyramidal geometry. The Cu cation is displaced by 0.2092 (8) Šfrom the basal plane formed by the four O atoms. Within the dinuclear mol-ecule, the Cu⋯Cu separation is 2.6453 (6) Å. Although a parallel, overlapped arrangement of isoquinoline ligands exists in the crystal structure; the longer face-to-face distance of 3.667 (5) Šsuggests there is no π-π stacking between isoquinoline ring systems.

Poly[octa-µ-aqua-tetra-aqua-bis(µ-5-sul-fon-atobenzene-1,3-dicarboxyl-ato)cobalt(II)tetra-sodium].

The title compound, [CoNa(4)(C(8)H(3)O(7)S)(2)(H(2)O)(12)](n), is a three-dimensional coordination polymer bridged by sulfoisophthalate trianions and water mol-ecules. The Co(II) atom, located on an inversion centre, is coordinated by two carboxyl-ate groups of the sulfoisophthalate trianions and by four water mol-ecules in a distorted CoO(6) octa-hedral geometry. Two independent Na(I) atoms also have a distorted octa-hedral coordination geometry formed by water, carboxyl-ate O and sulfonate O atoms. An extensive O-H⋯O and C-H⋯O hydrogen-bonding network is present in the crystal structure, as well as weak π-π stacking [centroid-centroid distance = 3.9553 (11) Å].

Poly[octa-µ-aqua-tetra-aqua-bis(µ(4)-5-sulfonatobenzene-1,3-dicarboxyl-ato)nickel(II)tetra-sodium].

In the crystal structure of the title compound, [Na(4)Ni(C(8)H(3)O(7)S)(2)(H(2)O)(12)](n), the Ni(II) cation occupies an inversion centre and is coordinated by the carboxyl groups of the sulfoisophthalate trianions and water mol-ecules in a distorted octa-hedral geometry. Two independent Na(I) atoms are connected by the carboxyl and sulfonate groups of the sulfoisophthalate ligands anions and water mol-ecules in a distorted octa-hedral geometry. The sulfoisophthalate ligands and coordinated water mol-ecules bridge the Ni(II) and Na(I) cations, forming a three-dimensional polymeric structure. Weak π-π stacking is present between parallel benzene rings [centroid-centroid distance = 3.9349 (10) Å]. Extensive O-H⋯O and C-H⋯O hydrogen bonding helps to stabilize the crystal structure.

Hexakis(1H-imidazole-κN)cobalt(II) triaqua-tris(1H-imidazole-κN)cobalt(II) bis-(naphthalene-1,4-dicarboxyl-ate).

The asymmetric unit of the title compound, [Co(C(3)H(4)N(2))(6)][Co(C(3)H(4)N(2))(3)(H(2)O)(3)](C(12)H(6)O(4))(2), contains two halves of crystallographically independent Co(II) complex cations, each assuming a distorted octa-hedral geometry, and one uncoordinated naphthalene-1,4-dicarboxyl-ate dianion. One Co(II) cation is located on an inversion center and is coordinated by six imidazole mol-ecules, while the other Co(II) cation is located on a twofold rotation axis and is coordinated by three water and three imidazole mol-ecules. The uncoordinated naphthalene-1,4-dicarboxyl-ate dianion links both Co(II) complex cations via O-H⋯O and N-H⋯O hydrogen bonding. One imidazole ligand is equally disordered over two sites about a twofold rotation axis, while the coordinated N atom of the imidazole is located on the twofold rotation axis. One water O atom has site symmetry 2.

4-Acetyl-pyridine-fumaric acid (2/1).

In the crystal structure of the title cocrystal, 2C(7)H(7)NO·C(4)H(4)O(4), the complete fumaric acid mol-ecule is generated by a crystallographic inversion centre. The two components of the cocrystal are linked by an O-H⋯N hydrogen bond.

Bis(3-hydroxy-pyridinium) fumarate.

The crystal structure of the title compound, 2C(5)H(6)NO(2) (+)·C(4)H(2)O(4) (2-), consists of 3-hydroxy-pyridinium cations and fumarate dianions. The dianion is located on an inversion center and the cation is linked to it by O-H⋯O and N-H⋯O hydrogen bonds. The cation is twisted with respect to the anion by 24.83 (5)°.

Bis(2,2'-diamino-4,4'-bi-1,3-thia-zole-κN,N)bis-(nitrato-κO)lead(II) dihydrate.

In the title compound, [Pb(NO(3))(2)(C(6)H(6)N(4)S(2))(2)]·2H(2)O, the Pb(II) cation is N,N'-chelated by two 2,2'-diamino-4,4'-bi-1,3-thia-zole (DABT) ligands and further is cis coordinated by two nitrate anions in a distorted PbN(4)O(2) octa-hedral geometry. One of the uncoordinated water mol-ecules is close to an inversion center and is disordered equally over two sites. Intra-molecular N-H⋯N and N-H⋯O inter-actions are present. An extensive hydrogen-bonding network of types N-H⋯O, O-H⋯O, O-H⋯N and O-H⋯S consolidates the crystal structure.

Poly[bis-(µ(2)-pyrimidine-2-carboxyl-ato-κO,N:O',N')calcium].

In the crystal structure of the title polymeric complex, [Ca(C(5)H(3)N(2)O(2))(2)](n), the Ca(II) cation has site symmetry m2 and is N,O-chelated by four pyrimidine-2-carboxyl-ate anions in a square-anti-prismatic geometry. The planar pyrimidine-2-carboxyl-ate anion is located on a crystallographic special position, three C atoms have site symmetry 2mm, while the carboxyl O atom, the pyrimidine N atom and the other C atom have site symmetry m. Each pyrimidine-2--carboxyl-ate anion bridges two Ca(II) cations, forming polymeric sheets extending parallel to (001). π-π stacking exists between parallel pyrimidine rings [centroid-centroid distance = 3.6436 (6) Å] of adjacent polymeric sheets. Weak C-H⋯O hydrogen bonding is also observed between these sheets.

Aqua-(2,2'-bipyridine)bis-(4-hydroxy-benzoato)zinc(II).

In the title complex, [Zn(C(7)H(5)O(3))(2)(C(10)H(8)N(2))(H(2)O)], the Zn(II) ion is coordinated by two 4-hydroxy-benzoate anions, one 2,2'-bipyridine mol-ecule and one water mol-ecule and displays a distorted octa-hedral geometry. One Zn-O bond [2.5300 (15) Å] is much longer than the others in the mol-ecule. In the crystal structure, the face-to-face separation of 3.547 (9) Šsuggests no π-π stacking between parallel bipyridine ring systems, and an extensive O-H⋯O hydrogen-bonding network between the coordinated water molecule, the phenol group and carboxylate O atoms is present.

Tetra-µ(2)-acetato-κO:O'-bis-[(isoquinoline-κN)copper(II)].

In the crystal structure of the title compound, [Cu(2)(CH(3)COO)(4)(C(9)H(7)N)(2)], the Cu(II) cation is coordinated by four acetate anions and one isoquinoline mol-ecule in a distorted square-pyramidal geometry; the Cu(II) cation is 0.1681 (6) Šfrom the basal coordination plane formed by the four O atoms. Each acetate anion bridges two Cu(II) cations to form the centrosymmetric dinuclear complex. Within the dinuclear mol-ecule, the Cu⋯Cu separation is 2.6459 (4) Å. A parallel arrangement of isoquinoline ligands of adjacent complexes is observed in the crystal structure; the face-to-face distance of 3.610 (10) Šsuggests there is no π-π stacking between isoquinoline ring systems.