Reducing the Bacterial Lag Phase Through Methylated Compounds: Insights from Algal-Bacterial Interactions.

The bacterial lag phase is a key period for resuming growth. Despite its significance, the lag phase remains underexplored, particularly in environmental bacteria. Here, we explore the lag phase of the model marine bacterium Phaeobacter inhibens when it transitions from starvation to growth with a microalgal partner. Utilizing transcriptomics and 13 C-labeled metabolomics, our study reveals that methylated compounds, which are abundantly produced by microalgae, shorten the bacterial lag phase. Our findings underscore the significance of methyl groups as a limiting factor during the lag phase and demonstrate that methyl groups can be harvested from algal compounds and assimilated through the methionine cycle. Furthermore, we show that methylated compounds, characteristic of photosynthetic organisms, induce variable reductions in lag times among bacteria associated with algae and plants. These findings highlight the adjustability of the bacterial lag phase and emphasize the importance of studying bacteria in an environmental context. One-Sentence Summary: Bacteria use algal compounds as a metabolic shortcut to transition from starvation to growth.

Bacteria contribute exopolysaccharides to an algal-bacterial joint extracellular matrix.

Marine ecosystems are influenced by phytoplankton aggregation, which affects processes like marine snow formation and harmful events such as marine mucilage outbreaks. Phytoplankton secrete exopolymers, creating an extracellular matrix (ECM) that promotes particle aggregation. This ECM attracts heterotrophic bacteria, providing a nutrient-rich and protective environment. In terrestrial environments, bacterial colonization near primary producers relies on attachment and the formation of multidimensional structures like biofilms. Bacteria were observed attaching and aggregating within algal-derived exopolymers, but it is unclear if bacteria produce an ECM that contributes to this colonization. This study, using Emiliania huxleyi algae and Phaeobacter inhibens bacteria in an environmentally relevant model system, reveals a shared algal-bacterial ECM scaffold that promotes algal-bacterial aggregation. Algal exudates play a pivotal role in promoting bacterial colonization, stimulating bacterial exopolysaccharide (EPS) production, and facilitating a joint ECM formation. A bacterial biosynthetic pathway responsible for producing a specific EPS contributing to bacterial ECM formation is identified. Genes from this pathway show increased expression in algal-rich environments. These findings highlight the underestimated role of bacteria in aggregate-mediated processes in marine environments, offering insights into algal-bacterial interactions and ECM formation, with implications for understanding and managing natural and perturbed aggregation events.

Association between area-level walkability and glycated haemoglobin: a Portuguese population-based study.

Diabetes poses a substantial disease burden, prompting preventive interventions. Physical inactivity, a major risk factor for type 2 diabetes, can potentially be mitigated by enhancing area-level walkability. Despite this, limited population-based studies have investigated the link between walkability and objective diabetes measures. Our study aims to estimate the association between area-level walkability and individual glycated haemoglobin levels in the Portuguese adult population without the diagnosis of diabetes. Data from the 2011 census and an updated street map were obtained to construct a walkability index based on residential density, land-use mix, and street connectivity. Individual health data were sourced from The National Health Examination Survey (INSEF) 2015, a representative survey of the Portuguese adult population. Gamma regression was employed for estimation of the main associations, revealing that residing in moderately walkable areas significantly reduced average glycated haemoglobin levels (Exp(ß) = 0.906; 95% CI: 0.821, 0.999) compared to the least walkable areas. The association was less pronounced and not statistically significant for the third tertile of walkability (Exp(ß) = 0.919; 95% CI: 0.822, 1.028). Our findings highlight a nonlinear protective association between walkability and glycated haemoglobin, emphasizing the potential policy implications for urban planning, diabetes prevention, and health promotion.

Factors influencing adverse events following COVID-19 vaccination.

Various novel platform technologies have been used for the development of COVID-19 vaccines. In this nested cohort study among healthcare workers in Australia and Brazil who received three different COVID-19-specific vaccines, we (a) evaluated the incidence of adverse events following immunization (AEFI); (b) compared AEFI by vaccine type, dose and country; (c) identified factors influencing the incidence of AEFI; and (d) assessed the association between reactogenicity and vaccine anti-spike IgG antibody responses. Of 1302 participants who received homologous 2-dose regimens of ChAdOx1-S (Oxford-AstraZeneca), BNT162b2 (Pfizer-BioNTech) or CoronaVac (Sinovac), 1219 (94%) completed vaccine reaction questionnaires. Following the first vaccine dose, the incidence of any systemic reaction was higher in ChAdOx1-S recipients (374/806, 46%) compared with BNT162b2 (55/151, 36%; p = 0.02) or CoronaVac (26/262, 10%; p < 0.001) recipients. After the second vaccine dose, the incidence of any systemic reaction was higher in BNT162b2 recipients (66/151, 44%) compared with ChAdOx1-S (164/806, 20%; p < 0.001) or CoronaVac (23/262, 9%; p < 0.001) recipients. AEFI risk was higher in younger participants, females, participants in Australia, and varied by vaccine type and dose. Prior COVID-19 did not impact the risk of AEFI. Participants in Australia compared with Brazil reported a higher incidence of any local reaction (170/231, 74% vs 222/726, 31%, p < 0.001) and any systemic reaction (171/231, 74% vs 328/726, 45%, p < 0.001), regardless of vaccine type. Following a primary course of ChAdOx1-S or CoronaVac vaccination, participants who did not report AEFI seroconverted at a similar rate to those who reported local or systemic reactions. In conclusion, we found that the incidence of AEFI was influenced by participant age and COVID-19 vaccine type, and differed between participants in Australia and Brazil.

The African Human Microbiome Portal: a public web portal of curated metagenomic metadata.

There is growing evidence that comprehensive and harmonized metadata are fundamental for effective public data reusability. However, it is often challenging to extract accurate metadata from public repositories. Of particular concern is the metagenomic data related to African individuals, which often omit important information about the particular features of these populations. As part of a collaborative consortium, H3ABioNet, we created a web portal, namely the African Human Microbiome Portal (AHMP), exclusively dedicated to metadata related to African human microbiome samples. Metadata were collected from various public repositories prior to cleaning, curation and harmonization according to a pre-established guideline and using ontology terms. These metadata sets can be accessed at https://microbiome.h3abionet.org/. This web portal is open access and offers an interactive visualization of 14 889 records from 70 bioprojects associated with 72 peer reviewed research articles. It also offers the ability to download harmonized metadata according to the user's applied filters. The AHMP thereby supports metadata search and retrieve operations, facilitating, thus, access to relevant studies linked to the African Human microbiome. Database URL:  https://microbiome.h3abionet.org/.

The genetic legacy of the expansion of Bantu-speaking peoples in Africa.

The expansion of people speaking Bantu languages is the most dramatic demographic event in Late Holocene Africa and fundamentally reshaped the linguistic, cultural and biological landscape of the continent1-7. With a comprehensive genomic dataset, including newly generated data of modern-day and ancient DNA from previously unsampled regions in Africa, we contribute insights into this expansion that started 6,000-4,000 years ago in western Africa. We genotyped 1,763 participants, including 1,526 Bantu speakers from 147 populations across 14 African countries, and generated whole-genome sequences from 12 Late Iron Age individuals8. We show that genetic diversity amongst Bantu-speaking populations declines with distance from western Africa, with current-day Zambia and the Democratic Republic of Congo as possible crossroads of interaction. Using spatially explicit methods9 and correlating genetic, linguistic and geographical data, we provide cross-disciplinary support for a serial-founder migration model. We further show that Bantu speakers received significant gene flow from local groups in regions they expanded into. Our genetic dataset provides an exhaustive modern-day African comparative dataset for ancient DNA studies10 and will be important to a wide range of disciplines from science and humanities, as well as to the medical sector studying human genetic variation and health in African and African-descendant populations.

Outbreak of Serratia marcescens in the Neonatal Intensive Care Unit of a Tertiary Care Hospital in Mexico.

Introduction: We describe an outbreak of Serratia marcescens (S. marcescens) infection in the neonatal intensive care unit at Women's Hospital in Sinaloa, Mexico. Methods: In April 2021, an outbreak of S. marcescens infection was identified. A case was identified as any patient who tested positive for S. marcescens and showed signs of an infectious process. Results: S. marcescens was isolated from the blood cultures of 15 neonates with clinical signs of neonatal sepsis. Statistical analysis showed that all neonates had an invasive medical device. The problem was controlled after hospital hygiene and sanitation measures were strengthened. Conclusion: The study provides evidence of an outbreak of nosocomial bacteremia due to the cross-transmission of S. marcescens. The findings highlight the need for hospitals to implement strict hygiene measures, especially regarding hand washing, to prevent future outbreaks.

Virulence-associated genes and antimicrobial resistance patterns in bacteria isolated from pregnant and nonpregnant women with urinary tract infections: the risk of neonatal sepsis.

Uropathogenic Escherichia coli (UPEC) is classified as the major causative agent of urinary tract infections (UTIs). UPEC virulence and antibiotic resistance can lead to complications in pregnant women and (or) newborns. Therefore, the aim of this study was to determine the etiological agents of UTIs, as well as to identify genes related to virulence factors in bacteria isolated from pregnant and nonpregnant women. A total of 4506 urine samples were collected from pregnant and nonpregnant women. Urine cultures were performed, and PCR was used to identify phylogroups and virulence-related genes. Antibiotic resistance profiles were determined. The incidence of UTIs was 6.9% (pregnant women, n = 206 and nonpregnant women, n = 57), and UPEC belonging to phylogroup A was the most prevalent. The presence of genes related to capsular protection, adhesins, iron acquisition, and serum protection in UPEC was associated with not being pregnant, while the presence of genes related to adhesins was associated with pregnancy. Bacteria isolated from nonpregnant women were more resistant to antibiotics; 36.5% were multidrug resistant, and 34.9% were extensively drug resistant. Finally, UTIs were associated with neonatal sepsis risk, particularly in pregnant women who underwent cesarean section while having a UTI caused by E. coli. In conclusion, UPEC isolated from nonpregnant women carried more virulence factors than those isolated from pregnant women, and maternal UTIs were associated with neonatal sepsis risk.

High-throughput bacterial co-encapsulation in microfluidic gel beads for discovery of antibiotic-producing strains.

Bacteria with antagonistic activity inhibit the growth of other bacteria through different mechanisms, including the production of antibiotics. As a result, these microorganisms are a prolific source of such compounds. However, searching for antibiotic-producing strains requires high-throughput techniques due to the vast diversity of microorganisms. Here, we screened and isolated bacteria with antagonistic activity against Escherichia coli expressing the green fluorescent protein (E. coli-GFP). We used microfluidics to co-encapsulate and co-culture single cells from different strains within picoliter gel beads and analyzed them using fluorescence-activated cell sorting (FACS). To test the methodology, we used three bacterial isolates obtained from Mexican maize, which exhibit high, moderate, or no antagonistic activity against E. coli-GFP, as determined previously using agar plate assays. Single cells from each strain were separately co-incubated into gel beads with E. coli-GFP. We monitored the development of the maize bacteria microcolonies and tracked the growth or inhibition of E. coli-GFP using bright-field and fluorescent microscopy. We correlated these images with distinctive light scatter and fluorescence signatures of each incubated bead type using FACS. This analysis enabled us to sort gel beads filled with an antagonistic strain, starting from a mixture of the three different types of maize bacteria and E. coli-GFP. Likewise, culturing the FACS-sorted beads on agar plates confirmed the isolation and recovery of the two antagonistic strains. In addition, enrichment assays demonstrated the methodology's effectiveness in isolating rare antibiotic-producer strains (0.01% abundance) present in a mixture of microorganisms. These results show that associating light side scatter and fluorescent flow cytometry signals with microscopy images provides valuable controls to establish successful high-throughput methods for sorting beads in which microbial interaction assays are performed.

Bacillus Calmette-Guérin vaccination for protection against recurrent herpes labialis: a nested randomised controlled trial.

Background: Recurrences of herpes simplex virus (HSV) in the orofacial region (herpes labialis or cold sores) impact quality-of-life. We aimed to study whether the bacille Calmette-Guérin (BCG) vaccine can attenuate cold sore recurrences through off-target immunomodulatory effects. Methods: In this nested randomised controlled trial within the multicentre, phase 3 BRACE trial, 6828 healthcare workers were randomised in 36 sites in Australia, the Netherlands, Spain, the United Kingdom and Brazil, to receive BCG-Denmark or no BCG (1:1 ratio using a web-based procedure) and followed for 12 months with 3-monthly questionnaires. Exclusion criteria included contraindication to BCG vaccine or previous vaccination with BCG within the past year, any other live-attenuated vaccine within the last month, or any COVID-specific vaccine. The intervention group received one intradermal dose of 0.1 mL of BCG-Denmark corresponding to 2-8 x 105 colony forming units of Mycobacterium bovis, Danish strain 1331. The primary outcome was the difference in restricted mean survival time (i.e., time to first cold-sore recurrence), in participants with frequent recurrent herpes labialis (≥4 recurrences/year), analysed by intention-to-treat. Secondary outcomes addressed additional questions, including analyses in other sub-populations. Adverse events were monitored closely during the first 3 months and were reported in all participants who received one dose of study drug according to intervention received. The BRACE trial is registered with ClinicalTrials.gov, NCT04327206. Findings: Between March 30, 2020 and February 18, 2021, 84 individuals with frequent recurrent cold sores were randomly assigned to BCG (n = 38) or control (n = 46). The average time to first cold-sore recurrence was 1.55 months longer in the BCG group (95% CI 0.27-2.82, p = 0.02) than the control group (hazard ratio 0.54, 95% CI 0.32-0.91; intention-to-treat). The beneficial effect of BCG was greater in the as-treated population (difference 1.91 months, 95% CI 0.69-3.12, p = 0.003; hazard ratio 0.45, 95% CI 0.26-0.76). In prespecified subgroup analyses, only sex modified the treatment effect (interaction p = 0.007), with benefit restricted to males. Over 12 months, a greater proportion of participants in the BCG group compared with the control group reported a decrease in duration (61% vs 21%), severity (74% vs 21%), frequency (55% vs 21%), and impact on quality of life (42% vs 15%) of cold sore recurrences. In participants who had ever had a cold sore, there was also a decrease in self-reported burden of recurrences in the BCG group. In participants who had never had a cold sore, there was an increased risk of a first episode in the BCG group (risk difference 1.4%; 95% CI 0.3-2.6%, p = 0.02). There were no safety concerns. Interpretation: BCG-Denmark vaccination had a beneficial effect on herpes labialis, particularly in males with frequent recurrences, but may increase the risk of a first cold sore. Funding: Bill & Melinda Gates Foundation, the Minderoo Foundation, Sarah and Lachlan Murdoch, the Royal Children's Hospital Foundation, Health Services Union NSW, the Peter Sowerby Foundation, SA Health, the Insurance Advisernet Foundation, the NAB Foundation, the Calvert-Jones Foundation, the Modara Pines Charitable Foundation, the UHG Foundation Pty Ltd, Epworth Healthcare, and individual donors.

Genome-wide variation in the Angolan Namib Desert reveals unique pre-Bantu ancestry.

Ancient DNA studies reveal the genetic structure of Africa before the expansion of Bantu-speaking agriculturalists; however, the impact of now extinct hunter-gatherer and herder societies on the genetic makeup of present-day African groups remains elusive. Here, we uncover the genetic legacy of pre-Bantu populations from the Angolan Namib Desert, where we located small-scale groups associated with enigmatic forager traditions, as well as the last speakers of the Khoe-Kwadi family's Kwadi branch. By applying an ancestry decomposition approach to genome-wide data from these and other African populations, we reconstructed the fine-scale histories of contact emerging from the migration of Khoe-Kwadi-speaking pastoralists and identified a deeply divergent ancestry, which is exclusively shared between groups from the Angolan Namib and adjacent areas of Namibia. The unique genetic heritage of the Namib peoples shows how modern DNA research targeting understudied regions of high ethnolinguistic diversity can complement ancient DNA studies in probing the deep genetic structure of the African continent.

Oral microbiome homogeneity across diverse human groups from southern Africa: first results from southwestern Angola and Zimbabwe.

BACKGROUND: While the human oral microbiome is known to play an important role in systemic health, its average composition and diversity patterns are still poorly understood. To gain better insights into the general composition of the microbiome on a global scale, the characterization of microbiomes from a broad range of populations, including non-industrialized societies, is needed. Here, we used the portion of non-human reads obtained through an expanded exome capture sequencing approach to characterize the saliva microbiomes of 52 individuals from eight ethnolinguistically diverse southern African populations from Angola (Kuvale, Kwepe, Himba, Tjimba, Kwisi, Twa, !Xun) and Zimbabwe (Tshwa), including foragers, food-producers, and peripatetic groups (low-status communities who provide services to their dominant neighbors). RESULTS: Our results indicate that neither host genetics nor livelihood seem to influence the oral microbiome profile, with Neisseria, Streptococcus, Prevotella, Rothia, and Porphyromonas being the five most frequent genera in southern African groups, in line with what has been shown for other human populations. However, we found that some Tshwa and Twa individuals display an enrichment of pathogenic genera from the Enterobacteriaceae family (i.e. Enterobacter, Citrobacter, Salmonella) of the Proteobacteria phylum, probably reflecting deficient sanitation and poor health conditions associated with social marginalization. CONCLUSIONS: Taken together, our results suggest that socio-economic status, rather than ethnolinguistic affiliation or subsistence mode, is a key factor in shaping the salivary microbial profiles of human populations in southern Africa.

Active aging awareness and well-being among older adults in Portugal.

Objective: This study aims to assess the active aging awareness of older adults in mainland Portugal and their levels of overall well-being and to identify social and health-related factors. Methods: A cross-sectional study was conducted with a representative sample of 613 older adults, aged 65 or older, who participated in the PROKnos - Knowing Social Prescribing needs of the elderly study in Portugal. The questionnaire consisted of the Active Ageing Awareness Questionnaire and the World Health Organization - Five Well-Being Index, as well as sociodemographic, economic, and health status questions. Correlation coefficients, t-tests for independent samples, and one-way ANOVA were used to explore potential associations between variables. Results: The active aging awareness levels were significantly higher for women (p = 0.031), and those who were younger (p = 0.011), more educated (p < 0.001), had a better financial situation (p < 0.001), and had better health (p < 0.001). The same pattern was found for well-being, except in relation to gender, as men had higher levels (p = 0.016). These variables were found to be correlated. Discussion: Even though active aging is an important strategy to implement, it is indispensable to consider the perceptions and conditions that need to be in place before that. This study reveals that several social and health-related factors are associated with well-being and active aging awareness, as well as the differences between groups that exist in mainland Portugal in relation to that. This emphasizes how vital it is to address social inequalities in active aging efforts, which are not necessarily uncovered when only considering actual active aging measures.

Aerobic bacteria produce nitric oxide via denitrification and promote algal population collapse.

Microbial interactions govern marine biogeochemistry. These interactions are generally considered to rely on exchange of organic molecules. Here we report on a novel inorganic route of microbial communication, showing that algal-bacterial interactions between Phaeobacter inhibens bacteria and Gephyrocapsa huxleyi algae are mediated through inorganic nitrogen exchange. Under oxygen-rich conditions, aerobic bacteria reduce algal-secreted nitrite to nitric oxide (NO) through denitrification, a well-studied anaerobic respiratory mechanism. The bacterial NO is involved in triggering a cascade in algae akin to programmed cell death. During death, algae further generate NO, thereby propagating the signal in the algal population. Eventually, the algal population collapses, similar to the sudden demise of oceanic algal blooms. Our study suggests that the exchange of inorganic nitrogen species in oxygenated environments is a potentially significant route of microbial communication within and across kingdoms.

Isolation and characterization of Lactobacillus casei A14.2, a strain with immunomodulating activity on Apis mellifera.

Considering the economic and environmental role played by bees and their present threats it is necessary to develop food supplements favoring their health. The aim of this work was to isolate and characterize an immunomodulating probiotic capable to improve the health of honeybee colonies. For this purpose, bacterial strains were isolated from Apis mellifera bees (N = 180) obtained at three apiaries. A total of 44 strains were isolated and 9 of them were identified as Lactobacillus having the capacity to grow under saccharose osmotic stress, at pH 4.0 and possessing a wide susceptibility to antibiotics. Results allowed to select two strains but finally only one of them, strain A14.2 showed a very significant immunomodulating activity. This strain increased the expression of mRNA codifying the antimicrobial peptides 24 h post-administration. We evaluated its growth kinetics under aerobic and microaerobic conditions and its survival in the presence of high concentrations of saccharose. Results demonstrated that Lactobacillus casei A14.2 strain was highly tolerant to oxygen and that it was able to adapt to saccharose enriched environments (50% and 100% w/v). Finally, L. casei A14.2 strain was administered monthly during summer and early fall to 4 honeybee colonies (2 controls and 2 treatments). The results showed a gradual sustained decrease of infestation (p < 0.05) by the pathogenic Nosema spp. but no reduction in the infestation by the mite Varroa destructor. These results suggest that the administration of this potential probiotic, may increase the resistance of honeybee colonies to infectious diseases caused by Nosema spp.

International Validation of Myopic Traction Maculopathy Staging System.

BACKGROUND AND OBJECTIVE: The aim of this study was to evaluate the interobserver agreement of the myopic traction maculopathy (MTM) staging system (MSS). PATIENTS AND METHODS: Each observer was asked to look at the MSS Table and then identify, in each optical coherence tomography scan, one among four stages of MTM in the retina, one among three stages in the fovea, and, as secondary findings, the presence or absence of an outer lamellar macular hole and the presence or absence of epiretinal abnormalities. The interobserver agreement value was calculated using the Gwet's AC1 unweighted and AC2 weighted statistics. The outcomes were interpreted as poor (<0.00), slight (0.00 to 0.20), fair (0.21 to 0.40), moderate (0.41 to 0.60), substantial (0.61 to 0.80), or almost perfect (0.81 to 1.00) agreement. RESULTS: The agreement, among 65 participants, was 0.62 (AC1) and 0.77 (AC2) for the retina stage; 0.63 (AC1) and 0.81 (AC2) for the fovea stage; 0.56 (AC1) for the outer lamellar macular hole; and 0.26 (AC1) for epiretinal abnormalities. CONCLUSION: The MSS is highly reproducible and helps ophthalmologists to share information on MTM in a more accurate and reliable way. [Ophthalmic Surg Lasers Imaging Retina 2023;54(3):153-157.].

Small mammals from the Caatinga: A dataset for the Brazilian semiarid biome.

The Caatinga is an exclusively Brazilian biome, and is the largest and most biodiverse Seasonal Tropical Dry Forest in the world. Despite that, the mammalian fauna, especially small mammals, is the least studied of all Brazilian biomes. In order to fill gaps and provide detailed information on small mammals (Didelphimorphia, Rodentia) in the Caatinga biome, we compiled reliable records focusing on richness, composition and some biometric data. These records came from mammal collections, papers, theses, books, and unpublished data, prioritizing records with vouchers housed in scientific collections. We compiled a total of 3133 records from 816 locations, resulting in a richness of 47 native species (12 marsupials and 35 rodents, plus three exotic rodents, Rattus rattus, Rattus norvegicus, and Mus musculus). This dataset includes records of three new species for the biome and its transition zone: the rodents Calomys mattevii, Holochilus oxe, and Nectomys squamipes. Of the total number of records, 1808 (57.71%) are from consulting activities, 95 (3.03%) are from zoonoses studies and 104 (3.32%) are from the National Plague Service (SNP). All nine Brazilian states with territory in the Caatinga have sampling data for small mammals, but the number of records and localities are unevenly distributed, with the state of Rio Grande do Norte having the lowest number of records and locations sampled. Our dataset is the first of its kind for the Caatinga biome and has considerable potential value for studies of habitat use, landscape ecology, macroecology, biogeography, and conservation. There are no copyright restrictions on the data. Please cite this data paper when the data are used in publications. We also request that researchers and teachers inform us of how they are using the data.

The linguistic and genetic landscape of southern Africa.

The present-day diversity of southern African populations was shaped by the confluence of three major pre-historic settlement layers associated with distinct linguistic strata: i) an early occupation by foragers speaking languages of the Kx'a and Tuu families; ii) a Late Stone Age migration of pre-Bantu pastoralists from eastern Africa associated with Khoe-Kwadi languages; iii) the Iron Age expansion of Bantu-speaking farmers from West-Central Africa who reached southern Africa from the western and eastern part of the continent. Uniting data and methodologies from linguistics and genetics, we review evidence for the origins, migration routes and internal diversification patterns of all three layers. By examining the impact of admixture and sex-biased forms of interaction, we show that southern Africa can be characterized as a zone of high contact between foraging and food-producing communities, involving both egalitarian interactions and socially stratified relationships. A special focus on modern groups speaking languages of the Khoe-Kwadi family further reveals how contact and admixture led to the generation of new ethnic identities whose diverse subsistence patterns and cultural practices have long puzzled scholars from various disciplines.

Engineering of global transcription factors in Bacillus, a genetic tool for increasing product yields: a bioprocess overview.

Transcriptional factors are well studied in bacteria for their global interactions and the effects they produce at the phenotypic level. Particularly, Bacillus subtilis has been widely employed as a model Gram-positive microorganism used to characterize these network interactions. Bacillus species are currently used as efficient commercial microbial platforms to produce diverse metabolites such as extracellular enzymes, antibiotics, surfactants, industrial chemicals, heterologous proteins, among others. However, the pleiotropic effects caused by the genetic modification of specific genes that codify for global regulators (transcription factors) have not been implicated commonly from a bioprocess point of view. Recently, these strategies have attracted the attention in Bacillus species because they can have an application to increase production efficiency of certain commercial interest metabolites. In this review, we update the recent advances that involve this trend in the use of genetic engineering (mutations, deletion, or overexpression) performed to global regulators such as Spo0A, CcpA, CodY and AbrB, which can provide an advantage for the development or improvement of bioprocesses that involve Bacillus species as production platforms. Genetic networks, regulation pathways and their relationship to the development of growth stages are also discussed to correlate the interactions that occur between these regulators, which are important to consider for application in the improvement of commercial-interest metabolites. Reported yields from these products currently produced mostly under laboratory conditions and, in a lesser extent at bioreactor level, are also discussed to give valuable perspectives about their potential use and developmental level directed to process optimization at large-scale.

The loss of biodiversity in Madagascar is contemporaneous with major demographic events.

Only 400 km off the coast of East Africa, the island of Madagascar is one of the last large land masses to have been colonized by humans. While many questions surround the human occupation of Madagascar, recent studies raise the question of human impact on endemic biodiversity and landscape transformation. Previous genetic and linguistic analyses have shown that the Malagasy population has emerged from an admixture that happened during the last millennium, between Bantu-speaking African populations and Austronesian-speaking Asian populations. By studying the sharing of chromosome segments between individuals (IBD determination), local ancestry information, and simulated genetic data, we inferred that the Malagasy ancestral Asian population was isolated for more than 1,000 years with an effective size of just a few hundred individuals. This isolation ended around 1,000 years before present (BP) by admixture with a small African population. Around the admixture time, there was a rapid demographic expansion due to intrinsic population growth of the newly admixed population, which coincides with extensive changes in Madagascar's landscape and the extinction of all endemic large-bodied vertebrates. Therefore, our approach can provide new insights into past human demography and associated impacts on ecosystems.