Methylphosphonate Degradation and Salt-Tolerance Genes of Two Novel Halophilic Marivita Metagenome-Assembled Genomes from Unrestored Solar Salterns

Aerobic bacteria that degrade methylphosphonates and produce methane as a byproduct have emerged as key players in marine carbon and phosphorus cycles. Here, we present two new draft genome sequences of the genus Marivita that were assembled from metagenomes from hypersaline former industrial salterns and compare them to five other Marivita reference genomes. Phylogenetic analyses suggest that both of these metagenome-assembled genomes (MAGs) represent new species in the genus. Average nucleotide identities to the closest taxon were <85%. The MAGs were assembled with SPAdes, binned with MetaBAT, and curated with scaffold extension and reassembly. Both genomes contained the phnCDEGHIJLMP suite of genes encoding the full C-P lyase pathway of methylphosphonate degradation and were significantly more abundant in two former industrial salterns than in nearby reference and restored wetlands, which have lower salinity levels and lower methane emissions than the salterns. These organisms contain a variety of compatible solute biosynthesis and transporter genes to cope with high salinity levels but harbor only slightly acidic proteomes (mean isoelectric point of 6.48).

Aerobic polychlorinated biphenyl-degrading bacteria isolated from the Tohoku region of Japan are not regionally endemic

In the Tohoku region of Japan, 72% of the land comprises mountain forest zones. During winter, severe climatic conditions include heavy snowfall. In such an environment, which is considered high in biodiversity, we assumed that aerobic bacteria would be diverse and would possess the ability to degrade polychlorinated biphenyls (PCBs). In this study, 78 environmental samples were collected from the Tohoku region and 56 aerobic PCB-degrading bacterial strains were isolated. They belonged to the genera Achromobacter, Rhodococcus, Pseudomonas, Stenotrophomonas, Comamonas, Pigmentiphaga, Xenophilus, Acinetobacter, and Pandoraea. Previously reported aerobic PCB-degrading bacterial strains isolated in Japan belonged to the same genera, except that the genera Acidovorax and Bacillus were not identified in the present study. In particular, the isolated Comamonas testosteroni strains YAZ2 and YU14-111 had high PCB-degrading abilities. Analysis of the sequences of the YAZ2 and YU14-111 strains showed that the gene structures of the bph operon, which encode enzymes associated with PCB degradation, were the same as those of the Acidovorax sp. KKS102 strain. Moreover, 2,3-biphenyl dioxygenase activity was responsible for the degradation characteristics of all the isolated strains. Overall, this study suggests that aerobic PCB-degrading bacteria are not specifically endemic to the Tohoku region but distributed across Japan.

Prevalence of Bacillus cereus in Ready-to-Eat Foods in Northern Perak, Malaysia

Food poisoning cases in Malaysia showed an increasing trend every year where 496 episodes were reported in 2018 as compared to 401 episodes in the same week of the year 2017. Bacillus cereus is one of the foodborne pathogens related to food poisoning cases in Malaysia. The main cause for the outbreak of B. cereus is the unregulated temperature during holding time. This study was conducted to detect the presence of aerobic bacteria and B. cereus present in ready-to-eat food in Northern Perak. A total of 83 food samples were collected and analyzed for the microbial count. The result shows that aerobic bacteria and B. cereus were detected in 28% of the samples. B. cereus count in food samples tested ranged from 100 cfu/g to 42000 cfu/g, whereas the aerobic bacteria recorded a range of 500 cfu/g to 2100000 cfu/g. The highest percentage of B. cereus was found in rice-based food, followed by meat, poultry, and gravy dishes. Positive colonies of B. cereus were further tested for anti-microbial resistance profile. Most B. cereus isolates showed resistance to tetracycline and clindamycin.

Dietary supplementation of Agaricus bisporus stalk meal on growth performance, carcass and organ traits, meat quality, cecum mesophilic aerobic bacteria counts and intestinal histology in broiler chickens

ABSTRACT: Effects of dietary Agaricus bisporus mixture or stalk or cap on growth performance, carcass components and some meat quality parameters, mesophilic aerobic bacterial counts, and intestinal histomorphology in broiler chickens were investigated. Two hundred and forty one-day-old male Ross 308 broiler chickens were divided into 4 experimental groups with 4 replicates, each including 15 birds. Chickens were fed with basal diet (C), mushroom mixture (MM, 10 g stalk+10 g cap/kg diet), mushroom stalk (MS, 20 g/kg diet) and mushroom cap (MC, 20 g/kg diet). Feed conversion ratio (FCR) was improved (P < 0.01) by dietary MS while feed intake (FI) decreased (P < 0.01) in all treatment groups compared to control. However, body weight gain (BWG) was decreased (P < 0.01) by MC inclusion. Mushroom supplemented groups had higher (P < 0.05) mesophilic aerobic bacteria in the cecum. MS inclusion increased villus height to crypt depth ratio in the jejunum (P < 0.01) and villus height in the ileum (P < 0.01) and jejunum (P < 0.05). MC increased (P < 0.01) crypt depth in the jejunum. There were no statistical differences among groups for carcass components (P > 0.05). The L* values were decreased (P < 0.01) in thigh meat but increased (P < 0.01) in breast meat by mushroom inclusion. The a* values were decreased (P < 0.01) and b* values were increased (P < 0.05) in both thigh and breast meat with mushroom addition to diet. The obtained results indicated that A. bisporus stalk meal at an inclusion level of 20 g/kg of diet had favourable effects on growth performance with higher feed efficiency, improved intestinal morphology with higher villus height and increased meat quality of broiler chickens.

The Comparison of the Microbiological Characteristics of Wet Dough and Dry Powder Tarhana’s and Evaluation of Possible Health Risks

Tarhana is a traditional food produced by different traditional methods and the materials used in production are changing from a region to another region. The total yeast and molds, total mesophilic aerobic bacteria, Escherichia Coli and enterococci bacteria count of wet dough Kastamonu tarhana and dry powdered tarhana samples were investigated in this study. All microorganisms examined in our study were detected in one of the wet dough tarhana samples. The highest total yeast and molds, total mesophilic aerobic bacteria, Escherichia coli and enterococci bacteria counts were determined for the wet dough tarhana samples to be 2.2×106, 6.6×107, 1.2×106 and 1.9×106 cfu/g, respectively. No growth of microorganism capable of reproduction was observed in the powdered tarhana produced industrially. In addition, the Escherichia coli and enterococci bacteria were not detected for any of the dry powder tarhana samples. It was seen that the microbial load of the wet tarhana produced at home in Kastamonu was higher than the powdered tarhana. The reason for this situation was thought to be due to poor production and hygiene conditions. The presence of Escherichia coli and enterococci bacteria in samples indicates that there is possible fecal contamination of the raw materials used in wet dough tarhana production. Electron microscope images of molds obtained in our study are similar to molds producing mycotoxins. These results show that the wet dough tarhana have a greater risk for microorganism development and human health compared to dry powder tarhana.

The pathway of sulfide oxidation to octasulfur globules in the cytoplasm of aerobic bacteria

Sulfur-oxidizing bacteria can oxidize hydrogen sulfide (H 2 S) to produce sulfur globules. Although the process is common, the pathway is unclear. In recombinant Escherichia coli and wild-type Corynebacterium vitaeruminis DSM20294 with SQR but no enzymes to oxidize zero valence sulfur, SQR oxidized H 2 S into short-chain inorganic polysulfide (H 2 S n , n≥2) and organic polysulfide (RS n H, n≥2), which reacted with each other to form long-chain GS n H (n≥2) and H 2 S n before producing octasulfur (S 8 ), the main component of elemental sulfur. GS n H also reacted with GSH to form GSnG (n≥2) and H 2 S; H 2 S was again oxidized by SQR. After GSH was depleted, SQR simply oxidized H 2 S to H 2 S n , which spontaneously generated S 8 . S 8 aggregated into sulfur globules in the cytoplasm. The results highlight the process of sulfide oxidation to S 8 globules in the bacterial cytoplasm and demonstrate the potential of using heterotrophic bacteria with SQR to convert toxic H 2 S into relatively benign S 8 globules. IMPORTANCE Our results support a process of H 2 S oxidation to produce octasulfur globules via SQR catalysis and spontaneous reactions in the bacterial cytoplasm. Since the process is an important event in geochemical cycling, a better understanding facilitates further studies and provides theoretical support for using heterotrophic bacteria with SQR to oxidize toxic H 2 S into sulfur globules for recovery.

Effect of Plant Species on the Performance and Bacteria Density Profile in Vertical Flow Constructed Wetlands for Domestic Wastewater Treatment in a Tropical Climate

Bacteria are frequently studied due to their involvement in pollutants transformation processes during wastewater treatment. In this study, the treatment efficiency, bacteria densities and their vertical profile were investigated in pilot-scale vertical flow constructed wetlands (VFCW) planted with different plant species under a tropical climate in west Africa. Five beds were planted with local plant species, i.e., Andropogon gayanus, Chrysopogon zizanioides, Echinochloa pyramidalis, Pennisetum purpureum and Tripsacum laxum, while one bed remained unplanted. These species have been rarely used in CWs while some (e.g., T. laxum) are tested for the first time. After a 7-month trial, bacteria densities were measured in substrate samples separated into six layers along the bed depth. Plants presence enhanced the bacterial density and VFCW efficiency; the removal rates of organic matter (90.9–95.9%; COD and 95.2–98.5%; BOD5), nitrogen (74.3–84%; TN and 76–84%; NH4-N) and phosphorus (77.4–96.9%; PO4-P) were higher by 5.9–24.1% compared to the control bed, providing an overall excellent treatment performance for a single-stage VFCW system. Small numbers of anaerobic bacteria were obtained in the VFCWs, explaining the low-to-zero NO3-N removal, except for the VFCWs with T. laxum and P. purpureum. Aerobic bacteria decreased from the upper to bottom layers from 17.4 to 0.1 × 106 CFU/g in the planted beds, while anaerobic bacteria increased from 0.1 to 2.1 × 106 CFU/g. Anaerobic bacteria were more abundant in the unplanted than in the planted beds. The total bacteria count was dominated by aerobic bacteria, and decreased from the surface towards the bottom. Overall, the VFCW with P. purpureum demonstrated the highest efficiency, indicating that this design is an effective and sustainable nature-based solution for wastewater treatment in a tropical climate.

Investigating the cultural-morphological features of rhizobacteria and allocating it from the cotton plant (Gossýpium hirsútum): in the example of irrigated meadow soils of Uzbekistan

This paper investigates the cultural-morphological, physiological and biochemical properties of bacterial isolates with stimulating properties isolated from the rhizosphere of cotton (Gossýpium hirsútum) grown in saline soils of Uzbekistan. The cells of the isolated culture No. 12 were found to be rod-shaped, 2-3x0.5-0.6 urn in size, single or chain-linked, Gram-positive aerobic bacteria producing spores. In studying the culture No. 146, its cells were in the form of thick, less mobile rods, 1-2x0.6-0.8 urn in size, forming thermostable spores. The spores were located in the center of the cell; the Gram-stained colonies in meat-peptone agar were round, bulging; the edges were flat, consistency oily, smooth and, mucous; and, the upper part was found to be shiny. Studies have shown that the isolates appertained to the genus Bacillus sr.

Pattern of Aerobic Bacteria in Adult Patients Isolated from Endotracheal Tubes in Tertiary Care Center

Introduction: Nosocomial infections have been described as an important issue among intubated patients which leads to significant morbidity and mortality. The pattern of microbiological colonization and antibiotic resistance are much valuable in this regard. Objectives: The aim of present study was to determine the pattern of aerobic bacteria isolated from endotracheal tubes in adult patients and determination of their antimicrobial susceptibility patterns. Materials and Methods: Specimens were collected from tracheal tubes of patients with endotracheal aspiration and microbiological investigations were done. The isolated bacteria were identified by using standard cultural and biochemical tests. Then antibiotic susceptibility testing was performed on the isolates by disc diffusion method according to clinical and laboratory Standards Institute (CLSI) guideline. Results: Among 104 participants 68 (65.4%) were female and 36 (34.6%) were male. Most of the patients were in the age group of 71-80 years (48.0%). From 104 positive growths, both Gram positive and Gram negative organisms were found. Maximum samples showed growth of gram negative organism. Antimicrobial susceptibility testing revealed that the most resistant Gram negative isolate was Klebsiella with highest resistance against Vancomycin (40.4%) and which showed highest sensitive against Cefotetan, Cefoxitin and Norfloxain (39.4%). Conclusions: It may be concluded that this study indicates the emergence of antibiotic resistant infections in the studied hospital. So, there is a need to improve the effectiveness of integrated infection control programs to control and manage nosocomial infections caused by highly resistant organisms. KYAMC Journal. 2021;12(3): 153-160