Symbiont genomic features and localization in the bean beetle, Callosobruchus maculatus

A pervasive pest of stored leguminous products, the bean beetle (Coleoptera: Chrysomelidae: Callosobruchus maculatus) associates with a simple bacterial community during adulthood. Despite its economic importance, little is known about the compositional stability, heritability, localization, and metabolic potential of the bacterial symbionts of C. maculatus. In this study, we applied community profiling using 16S rRNA gene sequencing to reveal a highly conserved bacterial assembly shared between larvae and adults. Dominated by Firmicutes and Proteobacteria, this community is localized extracellularly along the epithelial lining of the bean beetle’s digestive tract. Our analysis revealed only one species, Staphylococcus gallinarum (phylum Firmicutes), is shared across all developmental stages. Isolation and whole genome sequencing of S. gallinarum from the beetle gut yielded a circular chromosome (2.8 Mb) and one plasmid (45 kb). The strain encoded complete biosynthetic pathways for the production of B vitamins and amino acids, including tyrosine, which is increasingly recognized as an important symbiont-supplemented precursor for cuticle biosynthesis in beetles. A CAZyme search revealed the genome codes for a number of carbohydrate active enzymes, reflecting the nutritional ecology of their herbivorous host. The ontogenic conservation of the gut microbiota in the bean beetle - featuring a ‘core’ community composed of S. gallinarum - may be indicative of an adaptive role for the host. In clarifying symbiont localization and metabolic potential, we further our understanding and study of a costly pest of stored products. IMPORTANCE From supplementing essential nutrients to detoxifying plant secondary metabolites and insecticides, bacterial symbionts are a key source of adaptations for herbivorous insect pests. Despite the pervasiveness and geographical range of the bean beetle Callosobruchus maculatus, the role of microbial symbioses in its natural history remains understudied. Here, we demonstrate that the bean beetle harbors a simple gut bacterial community that is stable throughout development. This community localizes along the insect’s digestive tract and is largely dominated by Staphylococcus gallinarum. In elucidating symbiont metabolic potential, we highlight its possible adaptive significance for a widespread agricultural pest.

TOLUENE DEGRADATION BY FREE STAPHYLOCOCCUS GALLINARUM AND IMMOBILIZED ON MULTI-WALLED CARBON NANOTUBES

Hydrocarbons pollution is a most important environmental and healthanxiety . Using free and immobilized bacteria could be a suitable attitude to find a proper bioaugmentation agent. A toluene degrading bacterium was isolated from oil-contaminated environs (located in Bandar-Anzali, Guilan, Iran). The strain was molecularly identified as Staphylococcus gallinarum ATHH41 (Accession number: KX344723) by partial sequencing of 16SrDNA gene. The response surface methodology (RSM) was expended for biodegradation of the toluene by ATHH41. The central composite design (CCD) was utilized to optimize pH, temperature, and toluene concentration by ATHH41. In accordance with the optimization purpose of the Design-Expert software, the optimum circumstances of toluene degradation were obtained when pH, temperature and toluene concentration were adjusted to 7.68, 31.73°C and 630.04 mg.l-1, respectively. Multi-walled carbon nanotubes (MWCNTs) were used to immobilize the strain. Infrared spectroscopy and scanning electron microscopy showed that the cells adhered to the MWCNT surface and developed a biofilm. Results reveal that free cells were able to degrade 68.01% of the toluene as the sole carbon and energy source within 24 h under optimized conditions. The immobilized cells reached 95.68%.

Investigation of Enterotoxigenic Coagulase-negative Staphylococci Isolated from Local and Imported Dairy Products; a Microbiological Study

Coagulase negative staphylococci (CNS) have been recorded as a conveying vector for virulence genes and have been implicated in some cases of food poisoning. Research interest in CNS has increased over the past decade following their implication in infections in animals and humans. This study was aimed to detect CNS isolated from 150 dairy products (yoghurt, several types of cheese, Lork, and Serezh) in Sulaimani and Halabja governorate. Thirteen isolates out of 150 samples were identified as CNS using the VITEK® 2 system as an identification method. Results revealed that the most common isolates species including Staphylococcus saprophyticus, Staphylococcus sciuri and Staphylococcus xylosus each species have been identified in 3 samples separately (23%), followed by Staphylococcus vitulinus was in 2 samples (15%), Staphylococcus equorum found in 1 sample (8%), and Staphylococcus gallinarum also was in one sample (8%). The isolated CNS did not have enterotoxins type A to E according to RIDASCREEN kit test. Studying the growth limits of S. saprophyticus and S. vitulinus results showed that S. saprophyticus grew better at pH levels (5,6,7) at (25℃,37℃) and low NaCl concentration (5%), while low bacterial activity was observed at pH 4 at all temperatures and NaCl concentrations and also at 4℃ at all pH and NaCl levels. S. vitulinus behaviour was almost the same as S. saprophyticus but, S. vitulinus was able to tolerate different NaCl concentrations and overall had higher bacterial activity in all parameter’s interactions than S. saprophyticus. Investigating the effect of acetic acid and lactic acid on the growth of previous species where studied, S. saprophyticus grew better in different concentrations of L.A but S. vitulinus showed more activity than S. saprophyticus in A.A and the growth of both species inhibited at 0.4% of L.A at the first 24 hours of incubation.

КОРМОВАЯ ДОБАВКА ЦЕЛЛОБАКТЕРИН®-Т С ПРОЛОНГИРОВАННЫМ ДЕЙСТВИЕМ Бочкарева Е.В., Агеев Б.В., Кистина А.А., Бражник Е.А., Большаков В.Н., Новикова Н.И.

В производственных условиях было изучено сохранение эффекта пробиотической добавки Целлобактерин®-Т после отмены ее ввода в рацион кур-несушек. В опыте, проведенном в условиях птицефабрики «Авангард» (республика Мордовия), было задействовано 2 птичника (контрольная и опытная группы), в каждом из которых содержалось в клеточных батареях 130 тыс. голов несушек промышленного стада кросса Браун Ник. Птица контрольной группы в течение всех 60 дней эксперимента получала рацион без добавки; опытная группа получала тот же рацион, в который в течение первых 30 дней вводили добавку Целлобактерин®-Т (1 кг/т), а затем следующие 30 дней - рацион без добавки. В конце эксперимента проводился контрольный забой (60 голов от группы) со взятием образцов внутренних органов с последующим микробиологическим анализом для оценки пролонгированного действия добавки. Установлено, что в опытной группе количество условно-патогенной микрофлоры, выделенной из паренхиматозных органов и пазух головы кур, значительно снижалось, несмотря на отмену добавки: отмечено достоверное (p<0,05) снижение встречаемости видов Escherichia coli, Staphylococcus gallinarum, Avibacterium gallinarum и paragallinarum, Gallibacterium anatis. Патогенных видов в обеих группах выделено не было. По сохранности и яйценоскости опытная группа практически не отличалась от контрольной. Полученные результаты исследований могут быть использованы в качестве основы для разработки профилактических мероприятий по снижению циркуляции патогенной и условно-патогенной микрофлоры на промышленных птицеводческих предприятиях.

Traumatic Staphylococcus gallinarum endophthalmitis and detachment of a pallid retina

A rare case of Staphylococcus gallinarum endophthalmitis with intraocular foreign body (IOFB) was managed successfully by vitrectomy, IOFB removal and intravitreal antibiotics with steroids. Intraoperatively, the inferior retina was noted to be pale, possibly secondary to arteriolar occlusion/inflammation. This pale retina detached while peeling the vitreous, but spontaneously reattached postoperatively within a week. The case report describes the natural course of an iatrogenic detachment of pallid retina and the outcome of an uncommon ocular infection.