Active lupus in Argentina: Results of a multicenter and national registry.

OBJECTIVE: To evaluate the association between patients' characteristics and disease activity in an Argentine lupus registry. METHODS: Cross-sectional study. Disease activity was stratified into: Remission off-treatment: SLEDAI = 0, without prednisone and immunosuppressive drugs. Low disease activity Toronto Cohort (LDA-TC): SLEDAI ≤2, without prednisone or immunosuppressive drugs. Modified lupus low disease activity (mLLDAS): SLEDAI score of ≤4, with no activity in major organ systems and no new features, prednisone of ≤10 mg/day and/or immunosuppressive drugs (maintenance dose) and Active disease: SLEDAI score of >4 and prednisone >10 mg/day and immunosuppressive drugs. A descriptive analysis and logistic regression model were performed. RESULTS: A total of 1346 patients were included. Of them, 1.6% achieved remission off steroids, 0.8% LDA-TC, 12.1% mLLDAS and the remaining 85.4% had active disease. Active disease was associated with younger age (p ≤ 0.001), a shorter time to diagnosis (p ≤ 0.001), higher frequency of hospitalizations (p ≤ 0.001), seizures (p = 0.022), serosal disease (p ≤ 0.001), nephritis (p ≤ 0.001), higher SDI (p ≤ 0.001), greater use of immunosuppressive therapies and higher doses of prednisone compared to those on mLLDAS. In the multivariable analysis, the variables associated with active disease were the presence of pleuritis (OR 2.1, 95% CI 1.2-3.9; p = 0.007), persistent proteinuria (OR 2.5, 95% CI 1.2-5.5; p ≤ 0.011), nephritis (OR 2.5, 95% CI 1.2-5.6; p = .018) and hospitalizations (OR 8.9, 95% CI 5.3-16.0; p ≤ 0.001) whereas age at entry into the registry was negatively associated with it (OR 0.9, 95% CI 0.9-1.0; p = 0.029). CONCLUSION: Active disease was associated with shorter time to diagnosis, worse outcomes (SDI and hospitalizations) and renal, neurological and serosal disease.

B-cell depletion with obinutuzumab for the treatment of proliferative lupus nephritis: a randomised, double-blind, placebo-controlled trial.

OBJECTIVE: Randomised trials of type I anti-CD20 antibodies rituximab and ocrelizumab failed to show benefit in proliferative lupus nephritis (LN). We compared obinutuzumab, a humanised type II anti-CD20 monoclonal antibody that induces potent B-cell depletion, with placebo for the treatment of LN in combination with standard therapies. METHODS: Patients with LN receiving mycophenolate and corticosteroids were randomised to obinutuzumab 1000 mg or placebo on day 1 and weeks 2, 24 and 26, and followed through week 104. The primary endpoint was complete renal response (CRR) at week 52. Exploratory analyses through week 104 were conducted. The prespecified alpha level was 0.2. RESULTS: A total of 125 patients were randomised and received blinded infusions. Achievement of CRR was greater with obinutuzumab at week 52 (primary endpoint, 22 (35%) vs 14 (23%) with placebo; percentage difference, 12% (95% CI -3.4% to 28%), p=0.115) and at week 104 (26 (41%) vs 14 (23%); percentage difference, 19% (95% CI 2.7% to 35%), p=0.026). Improvements in other renal response measures, serologies, estimated glomerular filtration rate and proteinuria were greater with obinutuzumab. Obinutuzumab was not associated with increases in serious adverse events, serious infections or deaths. Non-serious infusion-related reactions occurred more frequently with obinutuzumab. CONCLUSIONS: Improved renal responses through week 104 were observed in patients with LN who received obinutuzumab plus standard therapies compared with standard therapies alone. Obinutuzumab was well tolerated and no new safety signals were identified. TRIAL REGISTRATION NUMBER: NCT02550652.

Multicenter lupus register from Argentina, the RELESSAR database: Influence of ethnicity on disease phenotype.

OBJECTIVE: The objective is to describe the main characteristics of patients with systemic lupus erythematosus (SLE) in Argentina and to examine the influence of ethnicity on the expression of the disease. PATIENTS AND METHODS: RELESSAR is a multicentre register carried out by 106 researchers from 67 rheumatologic Argentine centres. It is a cross-sectional study of SLE (1982/1997 ACR) patients. RELESSAR electronic database includes demographic, cumulative SLE manifestations, SELENA-SLEDAI, SLICC-SDI, Katz's severity and Charlson's comorbidity indexes and treatment patterns. RESULTS: We included 1,610 patients, 91.7% were female with a median age at diagnosis of 28.1 ± 12.8; 96.2% met ≥4 ACR 1982/97 criteria. Frequent manifestations were arthritis (83.5%), malar rash (79.5%), photosensitivity (75.3%), haematological (63.8%) and renal disease (47.4%), antinuclear antibodies (96%), anti-dsDNA (66.5%) and anti-Smith antibodies (29%). The mean Selena-SLEDAI score at last visit was 3.18 (SD 4.3) and mean SDI was 1 (SD 1.3). The accumulated treatments most frequently used were antimalarials (90.4%), corticosteroids (90%), azathioprine (31.8%), intravenous cyclophosphamide (30.2%), mycophenolate mofetil or mycophenolic acid (24.5%), methotrexate (19.3%), belimumab 5.3% and rituximab 5.1%. Refractory lupus was diagnosed in 9.3% of the cases. The main causes of death were lupus activity (25.0%), activity and concomitant infections (25.0%), infections (18.2%), vascular disease (13.6%) and cancer (4.5%). Mortality was associated with higher SLEDAI, Katz, damage indexes and comorbidities. Of the 1610 patients included, 44.6% were Caucasian, 44.5% Mestizo, 8.1% Amerindian and 1.2% Afro-Latin American. Mestizo patients had higher male representation, low socioeconomic status, more inadequate medical coverage, fewer formal years of education and shorter disease duration. Polyadenopathies and Raynaud's phenomenon were more frequent in Caucasians. In the logistic regression analysis higher damage index (OR 1.28, CI 95% 1.02-1.61, p = 0.03) remained associated to mestizo ethnicity. CONCLUSIONS: This study represents the largest number of adult patients with SLE studied in Argentina. Caucasian patients were differentiated by having Raynaud's phenomenon and polyadenopathy more frequently, while patients of Mestizo origin had higher damage indexes.

Whole genome sequence of the multi-resistant plant growth-promoting bacteria Streptomyces sp. Z38 with potential application in agroindustry and bio-nanotechnology.

The genus Streptomyces is widely recognized for its biotechnological potential. Due to a need to improve crops, clean up the environment and produce novel antimicrobial molecules exploiting Streptomyces has become a priority. To further explore the biotechnological potential of these organisms we analyzed the genome of the strain Streptomyces sp. Z38 isolated from contaminated roots tissues. Our analysis not only confirmed the ability of the strain to produce plant growth promoting traits but also a range of mechanisms to cope with the toxic effect of heavy metals through genes involved in metal homeostasis and oxidative stress response. The production of silver nanoparticles indicated that Streptomyces sp. Z38 may find utility in Green, Grey and Red biotechnology.

Chromium(VI) reduction in Streptomyces sp. M7 mediated by a novel Old Yellow Enzyme.

Old Yellow Enzymes play key roles in several cellular processes and have become an important family of enzymes with biotechnological potential. One of the major challenges of biotechnology consists of the bioremediation of co-polluted soils with organic and inorganic compounds. In co-contaminated areas, chromium normally exists in its more toxic and carcinogenic form Cr(VI). Microorganisms can reduce this metal to the insoluble and less toxic Cr(III). Streptomyces sp. M7 is a strain able to efficiently bioremediate polluted soils with γ-hexachlorocyclohexane and Cr(VI). The complete degradation pathway for γ-hexachlorocyclohexane was recently elucidated in this strain. In the present work, we confirmed the ability of Streptomyces sp. M7 to eliminate a high percentage of Cr(VI) from a synthetic culture medium. After a transcriptional study in the presence of Cr(VI), we also report the molecular cloning of a gene coding for an Old Yellow Enzyme with chromate reductase activity. Our results suggest that the elimination of Cr(VI) by Streptomyces sp. M7 is directly related to the activity of this Old Yellow Enzyme. The importance of our work is in identifying for the first time an Old Yellow Enzyme with chromate reductase activity in Streptomyces and Actinobacteria. Finding this enzyme helps understand chromium homeostasis in Streptomyces sp. M7, in addition to opening a new research window related to Old Yellow Enzymes from Actinobacteria.

Evaluation of the effectiveness of a bioremediation process in experimental soils polluted with chromium and lindane.

Bioremediation using actinobacterium consortia proved to be a promising alternative for the purification of co-contaminated environments. In this sense, the quadruple consortium composed of Streptomyces sp. M7, MC1, A5, and Amycolatopsis tucumanensis AB0 has been able to remove significant levels of Cr(VI) and lindane from anthropogenically contaminated soils. However, the effectiveness of the bioremediation process could not be evaluated only by analytical monitoring, which is complex mainly due to the characteristics of the matrix, producing non-quantitative analyte recoveries, or interferences in the detection stage and quantification. However, the effectiveness of the bioremediation process cannot be evaluated only through analytical monitoring, which is complex due mainly to the characteristics of the matrix, to the recoveries of non-quantitative analytes or to interferences in the detection and quantification stage. For this reason, it is essential to have tools of ecological relevance to assess the biological impact of pollutants on the environment. In this context, the objective of this work was to establish the appropriate bioassays to evaluate the effectiveness of a bioremediation process of co-contaminated soils. For this, five model species were studied: four plant species (Lactuca sativa, Raphanus sativus, Lycopersicon esculentum, and Zea mays) and one animal species (Eisenia fetida). On plant species, the biomarkers evaluated were inhibition of germination (IG) and the length of hypocotyls/steam and radicles/roots of the seedling. While on E. fetida, mortality (M), weight lost, coelomocyte concentration and cell viability were tested. These bioindicators and the battery of biomarkers quantified in them showed a different level of sensitivity, from maximum to minimum: E. fetida > L. esculentum > L. sativa > R. sativus ≫>Z. mays. Therefore, E. fetida and L. esculentum and their respective biomarkers were selected to evaluate the effectiveness of the bioremediation process due to the capability of assessing the effect on the flora and the fauna of the soil, respectively. The joint application of these bioindicators in a field scale bioremediation process is a feasible tool to demonstrate the recovery of the quality and health of the soil.

Effectiveness of the Zea mays-Streptomyces association for the phytoremediation of petroleum hydrocarbons impacted soils.

Restoring polluted sites by petroleum hydrocarbons is a challenge because of their complexity and persistence in the environment. The main objective of the present study was to investigate the performance of plant-actinobacteria system for the remediation of crude petroleum and pure-polycyclic aromatic hydrocarbons (PAHs) contaminated soils. The endophytic strain Streptomyces sp. Hlh1 was tested for its ability to degrade model PAHs (phenanthrene, pyrene and anthracene) in liquid minimal medium. Streptomyces sp. Hlh1 demonstrated the ability to grow on PAHs as sole carbon and energy source, reaching hydrocarbons removal of 63%, 93% and 83% for phenanthrene, pyrene and anthracene, respectively. Maize plant was chosen to study the impact of Streptomyces sp. Hlh1 inoculation on the dissipation of contaminants and plant growth. Thus, maize seedlings grown in soils contaminated with crude petroleum and pure-PAHs were inoculated with Streptomyces sp. Hlh1. Results showed that the endophyte inoculation increased contaminants removal. Maximum hydrocarbons removal (70%) was achieved in inoculated and planted soil contaminated with crude oil, while 61%, 59%, and 46% of hydrocarbons dissipation were registered for phenanthrene, pyrene and anthracene, respectively. These degradations rates were significantly higher compared to non-inoculated systems in all the treatments evaluated. Further, it was revealed that hydrocarbons (C8-C30) were efficiently degraded in plant-Streptomyces Hlh1 system. Moreover, the inoculation with the actinobacteria resulted significant plant development and enhanced photosynthetic pigments compared to plants grown in the other experimental conditions. The present study provide evidence that the inoculation of maize plants with Streptomyces sp. Hlh1 play a remarkable role in the removal of petroleum hydrocarbons, enhancing plant development in contaminated soils.

Fungal decomposers of leaf litter from an invaded and native mountain forest of NW Argentina.

The impact of plant species invasions on the abundance, composition and activity of fungal decomposers of leaf litter is poorly understood. In this study, we isolated and compared the relative abundance of ligninocellulolytic fungi of leaf litter mixtures from a native forest and a forest invaded by Ligustrum lucidum in a lower mountain forest of Tucuman, Argentina. In addition, we evaluated the relationship between the relative abundance of ligninocellulolytic fungi and properties of the soil of both forest types. Finally, we identified lignin degrading fungi and characterized their polyphenol oxidase activities. The relative abundance of ligninocellulolytic fungi was higher in leaf litter mixtures from the native forest. The abundance of cellulolytic fungi was negatively related with soil pH while the abundance of ligninolytic fungi was positively related with soil humidity. We identified fifteen genera of ligninolytic fungi; four strains were isolated from both forest types, six strains only from the invaded forest and five strains were isolated only from the native forest. The results found in this study suggest that L. Lucidum invasion could alter the abundance and composition of fungal decomposers. Long-term studies that include an analysis of the nutritional quality of litter are needed, for a more complete overview of the influence of L. Lucidum invasion on fungal decomposers and on leaf litter decomposition.

Cr(VI) and lindane removal by Streptomyces M7 is improved by maize root exudates.

Environmental mixed pollution by both organic and inorganic compounds are detected worldwide. Phytoremediation techniques have been proposed as ecofriendly methods for cleaning up polluted sites. Several studies have demonstrated enhanced dissipation of contaminants at the root-soil interface through an increase in microbial activity caused by the release of plant root exudates (REs). The aim of this study was to evaluate the effectiveness for Cr(VI) and lindane removal by Streptomyces M7 cultured in a co-contaminated system in presence of maize REs. Our results showed when REs were added to the contaminated minimal medium (MM) as the only carbon source, microbial removal of Cr(VI) and lindane increased significantly in comparison to contaminant removal obtained in MM with glucose 1 g L-1 . The maximum removal of 91% of lindane and 49.5% of Cr(VI) were obtained in the co-contaminated system. Moreover, Streptomyces M7 showed plant growth promoting traits which could improve plant performance in contaminated soils. The results presented in this study provide evidence that maize REs improved growth of Streptomyces M7 when REs were used as a carbon source in comparison to glucose. Consequently, lindane and Cr(VI) removal was considerably enhanced making evident the phytoremediation potential of the actinobacteria-plant partnership.

Long-term Outcome of Lupus Nephritis Class II in Argentine Patients: An Open Retrospective Analysis.

BACKGROUND: There is controversy in medical literature over the outcome of patients with lupus nephritis (LN) class II. The aim of this study was to explore the risk of histological transformation (HT) and possible factors related to negative response to treatment in patients with mesangial LN class II. METHODS: A retrospective and multicenter study was carried out that includes patients who had received a diagnosis of LN class II on their first renal biopsy. Creatinine, urine sediment, and proteinuria were recorded at the time of the first biopsy, 6 months, and 1, 2, and 5 years after the first biopsy. Response to treatment, HT, and long-term outcome were evaluated. RESULTS: Forty-one patients were included. The manifestation at first biopsy was proteinuria greater than 0.5 g/d in 28 patients (68.29%; 8 [28.57%] of 28 patients had nephrotic syndrome), hematuria in 18 patients (43.90%), and deterioration of renal function in 3 patients (7.31%). During the follow-up (median, 8 years; range, 1-35 years), a new biopsy was performed in 18 patients (43.90%), and in 17 patients (17/18 [94.44%]), there was HT. Median time at rebiopsy was 32 months (range, 11-305 months). Of the 18 patients who had a second biopsy, 10 (55.55%) were on hydroxychloroquine versus 100% (19/19) of patients who did not undergo the procedure (P = 0.001). A year after the first renal biopsy, there are data available from 34 patients; of them, 24 patients (70.58%) had achieved response, and 10 patients (29.41%) had no response (NR) (missing data in 7). A higher 24-hour urinary protein at 6 months was predictor of worse outcome at 1 year, with statistical significance difference for the nonresponder group (median proteinuria, 2.3 g/d [range, 0-4.7 g/d]) compared with responders (median proteinuria, 0.28 g/d [range, 0-1.7 g/d]) (P = 0.0133).In the long-term follow-up (5 years), HT was the main cause of unfavorable outcome and was measured in 78.57% of patients (11/14 patients). CONCLUSIONS: This series shows a high rate of HT in long-term follow-up. Proteinuria at 6 months made it possible to set aside patients who will have an unfavorable outcome in the long term and who will thus benefit from a more aggressive treatment. The results suggest that hydroxychloroquine had a nephroprotective effect.

[Severe hypereosinophilia as a paraneoplastic syndrome in a patient with differentiated thyroid cancer] / Hipereosinofilia severa como síndrome paraneoplásico en un paciente con cáncer diferenciado de tiroides.

In solid tumors, hypereosinophilia is a rare phenomenon and is mainly associated with mucin-secreting carcinomas. Thyroid tumors associated with neutrophilia and/or eosinophilia have been described exclusively in patients with anaplastic thyroid cancer. Eosinophilia associated with papillary thyroid cancer is extremely rare and there are very few cases currently described. It has been suggested that three cytokines, namely interleukin-3 (IL-3), interleukin-5 (IL-5), and granulocyte-macrophage colony-stimulating factor (GM-CSF), may act as a peptide potential eosinophilic. To date, only three patients with differentiated thyroid cancer associated with eosinophilia have been reported, two of the papillary type and one of the medullary type. A 48-year-old patient consulted in 2022 due to bilateral cervical lymphadenopathy of 3 years' duration associated with wasting syndrome and hypereosinophilia. PET CT was requested, which showed hypermetabolic focus in the right thyroid lobe and lymph node, lung, bone, and liver metastases; Thyroid ultrasound showing a nodule of high suspicion of malignancy and a conglomerate of lymphadenopathy in the right lobe with positive needle wash for thyroglobulin. Hypereosinophilia was evaluated with initial leukocytosis values of GB 30,310/mm3 (10,608/mm3 of eosinophils) to maximum values of GB 77,090/mm3 (eosinophils 20,814/mm3). It was interpreted as paraneoplastic syndrome and corticosteroid therapy was started at immunosuppressive doses without response. Our observations presented in this article are in line with most studies reflecting that paraneoplastic hypereosinophilia is characterized by more advanced disease and poor prognosis.

En los tumores sólidos la hipereosinofilia es un fenómeno raro y se asocia principalmente con carcinomas secretores de mucina. Los tumores tiroideos asociados a neutrofilia y/o eosinofilia se han descrito exclusivamente en pacientes con cáncer anaplásico de tiroides. La eosinofilia asociada con cáncer papilar de tiroides es extremadamente rara y se encuentran muy pocos casos descriptos actualmente. Se ha sugerido que tres citocinas, a saber, la interleucina-3 (IL-3), la interleucina-5 (IL-5) y el factor estimulante de colonias de granulocitos y macrófagos (GM-CSF), pueden actuar como un péptido eosinofílico potencial. Hasta el momento solo se han reportado tres pacientes con cáncer diferenciado de tiroides asociados a eosinofilia, dos de tipo papilar y uno de tipo medular. Paciente de 48 años consultó en el año 2022 por adenopatías cervicales bilaterales de 3 años de evolución asociado a síndrome consuntivo e hipereosinofilia. Se solicitó PET CT que evidenció foco hipermetabólico en lóbulo tiroideo derecho y metástasis ganglionares, pulmonares, óseas y hepáticas; ecografía tiroidea que evidencia en lóbulo derecho nódulo de alta sospecha de malignidad y conglomerado de adenopatías con lavado de aguja positivo para tiroglobulina. Evaluada la hipereosinofilia con valores iniciales de leucocitosis de GB 30310/mm3 (10608/mm3 de eosinófilos) hasta valores máximos de GB 77090/mm3 (eosinófilos 20814/mm3) se interpretó como síndrome paraneoplásico y se inició corticoterapia en dosis inmunosupresoras sin respuesta. Nuestras observaciones presentadas en este artículo están en línea con la mayoría de los estudios que reflejan que la hipereosinofilia paraneoplásica se caracteriza por una enfermedad más avanzada y un mal pronóstico.

Heavy metal resistant strains are widespread along Streptomyces phylogeny.

The genus Streptomyces comprises a group of bacteria species with high economic importance. Several of these species are employed at industrial scale for the production of useful compounds. Other characteristic found in different strains within this genus is their capability to tolerate high level of substances toxic for humans, heavy metals among them. Although several studies have been conducted in different species of the genus in order to disentangle the mechanisms associated to heavy metal resistance, little is known about how they have evolved along Streptomyces phylogeny. In this study we built the largest Streptomyces phylogeny generated up to date comprising six genes, 113 species of Streptomyces and 27 outgroups. The parsimony-based phylogenetic analysis indicated that (i) Streptomyces is monophyletic and (ii) it appears as sister clade of a group formed by Kitasatospora and Streptacidiphilus species, both genera also monophyletic. Streptomyces strains resistant to heavy metals are not confined to a single lineage but widespread along Streptomyces phylogeny. Our result in combination with genomic, physiological and biochemical data suggest that the resistance to heavy metals originated several times and by different mechanisms in Streptomyces history.

Combination of slurry-bioreactors and actinobacteria consortia as strategy to bioremediate chlordane-contaminated soils.

Soil contamination caused by pesticides poses a significant environmental challenge, and addressing it requires effective solutions. Bioremediation, combining the utilization of slurry-bioreactors and microbial consortia, emerges as an appropiated strategy to tackle this issue. Therefore, this research evaluated the chlordane (CLD) removal efficiency by a Streptomyces consortium through bioaugmentation of polluted soils, and slurry-bioreactors. For that, a Streptomyces defined consortium with CLD removal abilities was inoculated in soil microcosms and soil-slurry bioreactors (SB), with (SB-TSB) and without stimulation (SB-water). In soil, CLD presence has no negative effect on consortium growth. This was supported by comparing its duplication time (7.48 ± 0.14 h) with the obtained in the biotic control (7.45 ± 0.04 h). Furthermore, 17% of pesticide removal by microbial action was detected in the treated microcosms. In SB, the microbial development was not affected by the pesticide presence. In SB-TSB, the microbial growth was higher than in SB-water. This was supported by its lesser duplication time (7.27 ± 0.17 h) with respect to the non-stimulated systems (10.88 ± 0.29 h). However, SB-water showed the highest CLD removal ability (34.8%), with a concomitant increase in the chloride ion release. In the phytotoxicity test, the vigor index showed that the bioremediation in SB-water did not exert adverse effects greater than those generated by the CLD. Indeed, the root length increased after the treatment. These findings demonstrate the versatility of the Streptomyces consortium to remediate solid and semi-solid matrices impacted with pesticides, and the advantage of using bioaugmented SB to enhance the pollutants removal and accelerating the clean-up time required.

Developing a glyphosate-bioremediation strategy using plants and actinobacteria: Potential improvement of a riparian environment.

Glyphosate (Gly) and its principal degradation product, the aminomethylphosphonic acid (AMPA) were found in soils from a riparian environment in Argentina. Sixty-five actinobacteria were isolated from these soils, rhizosphere, and plants (Festuca arundinacea and Salix fragilis). The isolate Streptomyces sp. S5 was selected to be used as bioinoculant in a greenhouse test, in which plants, actinobacteria, and their combinations were assessed to bioremediate the riparian soil. The dissipation of both compounds were estimated. All treatments dissipated similarly the Gly, reaching 87-92 % of dissipation. AMPA, dissipation of 38 % and 42 % were obtained by Salix and Festuca, respectively, while they increased to 57 % and 70 % when the actinobacterium was added to each planted system. Regarding the total dissipation, the higher efficiencies for both compounds were achieved by the non-planted soils bioaugmented with the actinobacterium, with 91 % of Gly dissipated and 56 % for AMPA. According to our study, it could be suggested which strategy could be applied depending on the bioremediation type needed. If in situ bioremediation is necessary, the combination of phytoremediation and actinobacteria bioaugmentation could be convenient. On the other hand, if ex situ bioremediation is needed, the inoculation of the soil with an actinobacterium capable to dissipate Gly and AMPA could be the more efficient and easier alternative.

Bacterial bio-resources for remediation of hexachlorocyclohexane.

In the last few decades, highly toxic organic compounds like the organochlorine pesticide (OP) hexachlorocyclohexane (HCH) have been released into the environment. All HCH isomers are acutely toxic to mammals. Although nowadays its use is restricted or completely banned in most countries, it continues posing serious environmental and health concerns. Since HCH toxicity is well known, it is imperative to develop methods to remove it from the environment. Bioremediation technologies, which use microorganisms and/or plants to degrade toxic contaminants, have become the focus of interest. Microorganisms play a significant role in the transformation and degradation of xenobiotic compounds. Many Gram-negative bacteria have been reported to have metabolic abilities to attack HCH. For instance, several Sphingomonas strains have been reported to degrade the pesticide. On the other hand, among Gram-positive microorganisms, actinobacteria have a great potential for biodegradation of organic and inorganic toxic compounds. This review compiles and updates the information available on bacterial removal of HCH, particularly by Streptomyces strains, a prolific genus of actinobacteria. A brief account on the persistence and deleterious effects of these pollutant chemical is also given.

Enhanced biodegradation of hexachlorocyclohexane (HCH) isomers by Sphingobium sp. strain D4 in the presence of root exudates or in co-culture with HCH-mobilizing strains.

Lindane and other 1,2,3,4,5,6-hexachlorocyclohexane (HCH) isomers are persistent organic pollutants highly hydrophobic, which hampers their availability and biodegradation. This work aimed at (i) investigating genes encoding enzymes involved in HCH degradation in the bacterium Sphingobium sp. D4, (ii) selecting strains, from a collection of environmental isolates, able to mobilize HCHs from contaminated soil, and (iii) analysing the biodegradation of HCHs by strain D4 in co-culture with HCH-mobilizing strains or when cultivated with root exudates. Fragments of the same size and similar sequence to linA and linB genes were successfully amplified. Two isolates, Streptomyces sp. M7 and Rhodococcus erythropolis ET54b able to produce emulsifiers and to mobilize HCH isomers from soil were selected. Biodegradation of HCH isomers by strain D4 was enhanced when co-inoculated with HCH mobilizing strains or when cultivated with root exudates. The degrader strain D4 was able to decompose very efficiently HCHs isomers, reducing their concentration in soil slurries by more than 95% (from an average initial amount of 50 ± 8 mg HCH kg-1 soil) in 9 days. The combination of HCH-degrading and HCH-mobilizing strains can be considered a promising inoculum for future soil bioremediation studies using bioaugmentation techniques or in combination with plants in rhizodegradation assays.

The Bacterial and Fungal Gut Microbiota of the Greater Wax Moth, Galleria mellonella L. Consuming Polyethylene and Polystyrene.

Plastic production has been increasing exponentially in the last 60 years, but plastic disposal is out of control, resulting in the pollution of all ecosystems on Earth. Finding alternative environmentally sustainable choices, such as biodegradation by insects and their associated gut microbiota, is crucial, however we have only begun to characterize these ecosystems. Some bacteria and one fungus have been previously identified in the gut of Greater Wax Moth larvae (Galleria mellonella L., Lepidoptera, Pyralidae) located mainly in the Northern hemisphere. The aim of this study was to describe changes in the gut microbiota associated with the consumption of polyethylene and polystyrene by the Greater Wax Moth in Argentina, considering both bacteria and fungi. Larvae were fed polyethylene, polystyrene and beeswax as control for 7 days. Next generation sequencing revealed changes in the bacterial gut microbiome of the wax moth larvae at the phyla and genus levels, with an increase in two Pseudomonas strains. The fungal communities showed no differences in composition between diets, only changing in relative abundance. This is the first report of both bacterial and fungal communities associated with a plastivore insect. The results are promising and call for more studies concerning a potential multi-kingdom synergy in the plastic biodegradation process.

Beneficial traits of root endophytes and rhizobacteria associated with plants growing in phytomanaged soils with mixed trace metal-polycyclic aromatic hydrocarbon contamination.

The diversity of cultivable bacteria associated with plants from phytomanaged soils with mixed trace metal (TM) and polycyclic aromatic hydrocarbon (PAH) contamination in Pierrelaye (France) was evaluated. The emphasis was on the cultivable bacterial community since the overall objective is to obtain inoculants to improve the remediation of this type of contaminated site. Root endophytic and rhizosphere soil bacterial counts were determined, and isolates were pooled by amplified rDNA restriction analysis and identified by 16S rDNA sequencing. Isolates were further characterized for the production of plant growth-promoting (PGP) substances, and resistance to TM. The selected strains were evaluated for their ability to degrade PAHs. The potential of cell-free microbial supernatant to increase the mobilisation of PAHs from the polluted soil of Pierrelaye was also evaluated. Proteobacteria and Actinobacteria dominated the collection of isolates, and differences in taxonomic diversity were observed between plant species (Populus or Zea mays) and depending on the remediation treatment (Populus inoculation with mycorrhizae or Populus intercropping with Alnus). The majority of isolates exhibited at least one of the tested PGP traits, as well as resistance to more than one TM. Several rhizosphere, endophyte and even one bulk soil isolate showed high rates of fluoranthene and pyrene reduction. The endophyte Rhizobium strain MR28 isolated from maize and degrading pyrene produced bioemulsifying molecules capable of improving the availability of PAHs from the soil of Pierrelaye. A selection of the most interesting strains was made for further re-inoculation experiments in order to assess their potential in rhizoremediation processes.

Assessment of the Streptomyces-plant system to mitigate the impact of Cr(VI) and lindane in experimental soils.

Phytoremediation techniques have been proposed as ecological methods to clean up contaminated sites. This study is aimed to evaluate the effect of the Streptomyces sp. Waksman & Henrici and Zea mays L. plant system on the dissipation of Cr(VI) and/or lindane from a co-contaminated soil, being 2 mg kg-1 of lindane and 150 mg kg-1 of chromium used. Lindane dissipation was improved in the presence of plant-microorganism association; however, Cr(VI) removal was higher when plants or the microorganism were separately. In co-contaminated systems, chromium content in plant tissues was lower than metal content in plants grown only with Cr(VI), suggesting that lindane could interfere with metal accumulation in the plant. The high malondialdehyde (MDA) concentration detected in non-inoculated plants grown with chromium could be consequence of high metal concentration in plant tissues. Interestingly, plants inoculated with Streptomyces sp. Z38 growing with Cr(VI) showed decrease in MDA concentration, indicating that the bacterium could activate defense mechanisms in the plant. Also, inoculated plants showed the highest value of superoxide dismutase activity. Lettuce plants used as bioindicators grew better in biologically treated soils compared with lettuce grown on non-treated soil. The results presented in this work provide the basis that will allow the optimization of future trials on a larger scale.

Characterization of native Bacillus thuringiensis strains and selection of an isolate active against Spodoptera frugiperda and Peridroma saucia.

Twelve Bacillus thuringiensis (Bt) strains, isolated from larvae and soil samples in Argentina, were molecularly and phenotypically characterized and their insecticidal activities against Spodoptera frugiperda and Peridroma saucia were determined. One isolate--Bt RT--produced more than 93% mortality on first instar larvae of both species, which was higher than that produced by the reference strain Bt 4D1. Bt RT carried a different cry gene profile than Bt 4D1. Scanning electron microscopy showed the presence of bipyramidal and cuboidal crystals. Phenotypic characterization revealed lytic enzymes that could contribute to Bt pathogenicity.