Streptococcus zooepidemicus (SZ) is an aerotolerant bacteria and its ability to survive under reactive oxidant challenge raises the question of the existence of a defense system. Thus growth, hyaluronic acid (HA) and hydrogen peroxide (H2O2) production by SZ in the presence of increasing concentration of Mn2+ were studied. The results suggested that the tested strain supported growth and HA production in cultures treated with 1 and 10 mM of Mn2+ regardless of H2O2 presence in the medium. This showed that SZ have acquired elaborate defense mechanisms to scavenge oxygen toxicity and thus protect cells from direct and indirect effect of this radical. In contrast, cells treated with 25 mM Mn2+ were sensitive, in which, the HA production was reduced considerably. Thus showing that the oxygen scavenger systems of the cells may be fully saturated at this concentration.
Dose-Response Relationship, Drug ; Free Radical Scavengers/*metabolism ; Hyaluronic Acid/*biosynthesis ; Hydrogen Peroxide/*metabolism ; Magnesium/*pharmacology ; Reactive Oxygen Species/*metabolism ; Streptococcus equi/*drug effects ; Streptococcus equi/metabolism ; Superoxide Dismutase/physiology

Agitation plays an important role in the hyaluronic acid (HA) fermentation process. However, views about the effect of agitation on HA production remain controversial. We investigated the effect of agitation on cell growth and HA synthesis during HA fermentation process by using Computational Fluid Dynamics (CFD) technology. The results showed that the biomass and HA yield changed a little with the increase of impeller speed, but the HA molecular weight firstly increased and then decreased. The results of phase agitation control strategy demonstrated that the influence of agitation on the HA molecular weight mainly exhibited at the stage of HA synthesis. Moreover, the CFD simulation results indicated that when impeller speed increased, the mixing time reduced while the shear rate increased significantly. The removal of anchor could moderate the contradiction between the mixing time and shear rate, and finally the HA molecular weight increased by 23.9%. The results of this work could provide guidelines for optimizing the HA fermentation, as well as the bioreactor design and scaling up.
Bioreactors ; Fermentation ; Hyaluronic Acid ; biosynthesis ; chemistry ; Hydrodynamics ; Numerical Analysis, Computer-Assisted ; Shear Strength ; Streptococcus equi ; growth & development ; metabolism

Hyaluronic acid (HA) is widely used in many fields, such as medicine, cosmetics and food. The bioactivity of HA depends on its molecular weight (Mw). Owing to the important physiological activities and special physiological functions, HA oligosaccharides have important application prospects in medicine fields. Streptococcus zooepidemicus has wide applications in commercial production of HA, due to its short fermentation cycle and strong production intensity. In order to efficiently synthesize HA oligosaccharides and solve the dissolved oxygen in the fermentation process, in this study, we overexpressed HA synthase (HasA) and introduced and optimized the leech hyaluronidase LHAase in Streptococcus zooepidemicus WSH-24. As a result, HA oligosaccharides were efficiently produced with improved dissolved oxygen. After 24 h, HA oligosaccharides production intensity reached to 294.2 mg/(L·h), and the concentration accumulated to 0.97 g/L in flask cultures, which was 1.82 times of the wild strain. Impressively, HA oligosaccharides were increased to 7.06 g/L in 3 L fermentor. The constructed Streptococcus zooepidemicus strain for producing HA oligosaccharides would have broad application prospects.
Bioreactors ; Fermentation ; Hyaluronan Synthases ; genetics ; metabolism ; Hyaluronic Acid ; genetics ; metabolism ; Industrial Microbiology ; Oligosaccharides ; genetics ; metabolism ; Streptococcus equi ; genetics ; metabolism

An outbreak of fatal hemorrhagic pneumonia with 70~90% morbidity and 50% mortality occurred in an animal shelter in Yangju, Gyeonggi Province, Korea. Clinically, the affected dogs showed severe respiratory distress within 48 h after arriving in the shelter. The dead were found mainly with nasal bleeding and hematemesis. At necropsy, hemothorax and hemorrhagic pneumonia along with severe pulmonary consolidation was observed, though histopathological analysis showed mainly hemorrhagic bronchopneumonia. Lymphoid depletion was inconsistently seen in the spleen, tonsil and bronchial lymph node. Gram-positive colonies were shown in blood vessels or parenchyma of cerebrum, lung, liver, spleen, and kidney. Also, Streptococcus (S.) equi subsp. zooepidemicus was isolated from the various organs in which the bacterium was microscopically and histologically detected. In addition, approximately 0.9 Kb specific amplicon, antiphagocytic factor H binding protein, was amplified in the bacterial isolates. In this study, we reported an outbreak of canine hemorrhagic bronchopneumonia caused by S. equi subsp. zooepidemicus in an animal shelter in Yangju, Korea.
Animals ; Disease Outbreaks/*veterinary ; Dog Diseases/*epidemiology/*microbiology/pathology ; Dogs ; Korea/epidemiology ; Pneumonia, Bacterial/epidemiology/microbiology/pathology/*veterinary ; Streptococcus equi/isolation & purification/*physiology

To analyze the immunogenicity and protective ability of recombinant IgG-binding protein (EAG) of Streptococcus equi subspecies equi and to evaluate its value when used as equine vaccine antigen, EAG gene was amplified by PCR and inserted into pET-28a vector. The EAG recombinant proteins were expressed and purified to immune mice. The serum antibody and challenge protection were tested. The purified recombinant protein of EAG was 26 kDa, and the protein reacted specifically with positive serum of Streptococcus equi subspecies equi. The mice antibody level for EAG immunization group was 1∶8 100. The immunological protection result showed that the protection rate of the EAG recombinant protein was 90%. The results suggested that the EAG protein has good immunogenicity and immunological protection, and it can effectively increase the humoral immune response and immunological protection of mice.
Animals ; Antibodies, Bacterial ; blood ; Antigens, Bacterial ; immunology ; Bacterial Proteins ; immunology ; Bacterial Vaccines ; immunology ; Immunity, Humoral ; Immunoglobulin G ; blood ; Mice ; Polymerase Chain Reaction ; Protein Binding ; Recombinant Proteins ; immunology ; Streptococcal Infections ; prevention & control ; Streptococcus equi ; Vaccination

In the present study 41 mucoid growing Streptococcus equi subsp. zooepidemicus strains (37 strains isolated from healthy two from diseased pigs, two strains isolated from healthy monkeys) appeared to be phenotypically and genotypically identical to mucoid growing S. equi subsp. zooepidemicus strains isolated from a previously described outbreak among the pig and monkey population on the island of Bali, Indonesia. These findings indicate that the mucoid growing S. equi subsp. zooepidemicus clone was still present in the pig and monkey population in Indonesia.
Animals ; DNA, Bacterial/chemistry/genetics ; Electrophoresis, Gel, Pulsed-Field/veterinary ; Haplorhini ; Indonesia/epidemiology ; Monkey Diseases/epidemiology/*microbiology ; Polymerase Chain Reaction/veterinary ; Polymorphism, Restriction Fragment Length ; RNA, Ribosomal, 16S/chemistry/genetics ; Streptococcal Infections/epidemiology/microbiology/*veterinary ; Streptococcus equi/*classification/genetics/growth&development ; Swine ; Swine Diseases/epidemiology/*microbiology