Important Consequences For Human Health Research Articles

The maternal gut microbiome in pregnancy: implications for the developing immune system.

The gut microbiome has important roles in host metabolism and immunity, and microbial dysbiosis affects human physiology and health. Maternal immunity and microbial metabolites during pregnancy, microbial transfer during birth, and transfer of immune factors, microorganisms and metabolites via breastfeeding provide critical sources of early-life microbial and immune training, with important consequences for human health. Only a few studies have directly examined the interactions between the gut microbiome and the immune system during pregnancy, and the subsequent effect on offspring development. In this Review, we aim to describe how the maternal microbiome shapes overall pregnancy-associated maternal, fetal and early neonatal immune systems, focusing on the existing evidence and highlighting current gaps to promote further research.

The Impact of Gut Bacterial Metabolites on Brain Disorder

The gut microbiome has been connected with human health and sickness, including all those affecting the brain, according to new evidence. Abnormalities in this microbiota-gut-brain axis have emerged as a significant component in the pathophysiology of depression, prompting exploratory research into the neuro-active potential of gut microbial metabolic products. Over the last decade, research has revealed a plethora of complicated interactions between the microbiota and the immunological and metabolic systems, many of which have important consequences for human health. Therefore in review, we emphasise accumulating evidence suggesting the microbiome exerts effect on the brain via multiple routes linking the stomach to the central nervous system. While knowledge of the influence of gut bacteria on neurological function is still developing, understanding the gut-microbiome-brain links has the potential to transform neuroscience by discovering possibly new etiologies for mental and neurodegenerative diseases. Overall, our results show that patients with diverse brain disorders have changed bacterial metabolites, as well as the possible neuroactive effects of gut-derived SCFAs, p-cresol, serotonin derivatives, and bacterial amyloids on disease onset and progression. The results of this study might lead to more understanding of the gut–brain axis and, as a response, to possible diagnostic, therapeutic, or preventative measures for brain disorders. Keywords:

Medically important trombiculids: a systematic review of the global distribution and clinical consequences of their bites

Background: Mites are among the smallest arthropods that can be seen without magnification, were the use of dermatoscopy is an invaluable tool. They are a cosmopolitan pest, and at the moment more than 250 species have been shown to produce problems for humans and animals alike. These mites are capable of producing a wide array of clinical signs and symptoms, from local to systemic, from mild to severe, as well as transmitting pathogens. This study aimed to provide an update to the clinical impact on human health, the distribution and species involved in the clinical conditions produced by trombiculids through a systematic review. Background: Mites are among the smallest arthropods that can be seen without magnification, were the use of dermatoscopy is an invaluable tool. They are a cosmopolitan pest, and at the moment more than 250 species have been shown to produce problems for humans and animals alike. These mites are capable of producing a wide array of clinical signs and symptoms, from local to systemic, from mild to severe, as well as transmitting pathogens. This study aimed to provide an update to the clinical impact on human health, the distribution and species involved in the clinical conditions produced by trombiculids through a systematic review. Methods: A systematic literature review was conducted in Medline, Lilacs, Redalyc, Scopus, SciELO and Google Scholar, were we use as a threshold of publication date the year 2008. We limited the search strategy to articles published in Portuguese, French, English and Spanish. Eligible studies were case reports and case series that reported outcomes in humans caused by trombiculid bites. Patient-level and study-level information was extracted. Results: The literature search yielded 832 studies; 13 were case reports, 4 case series and 2 descriptive studies reporting a total of 49 cases. Most patients were male, and the median age was 33.7±6.4 years old. The most frequently reported symptoms were local erythema, pruritus and papules. No deaths were documented. Trombiculids from the genera Trombicula, Eutrombicula and Leptotrombidium appear to be the most commonly reported. Discussion: Trombiculiasis is an infestation caused by the larval stage of various types of mites, known as chiggers, they belong to the class Arachnida and the family Trombiculidae. This systematic review provides an overview of the trombiculids of clinical importance, their distribution and effects of the bite on human health. Our results show that there are different species of mites that can have important consequences for human health. No fatal cases owere registered.Even so, the transmission of scrub typhus is important and remains one of the most life-threatening rickettsial infections in some regions of Asia. Conclusions: The bite of different species of trombiculids around the world can cause a wide array of clinical consequences to human health. Even as mortality appear to be nonexistent, trombiculid bites must be adequately diagnosed and treated properly: A systematic literature review was conducted in Medline, Lilacs, Redalyc, Scopus, SciELO and Google Scholar, were we use as a threshold of publication date the year 2008. We limited the search strategy to articles published in Portuguese, French, English and Spanish. Eligible studies were case reports and case series that reported outcomes in humans caused by trombiculid bites. Patient-level and study-level information was extracted. Results: The literature search yielded 832 studies; 13 were case reports, 4 case series and 2 descriptive studies reporting a total of 49 cases. Most patients were male, and the median age was 33.7±6.4 years old. The most frequently reported symptoms were local erythema, pruritus and papules. No deaths were documented. Trombiculids from the genera Trombicula, Eutrombicula and Leptotrombidium appear to be the most commonly reported. Discussion: Trombiculiasis is an infestation caused by the larval stage of various types of mites, known as chiggers, they belong to the class Arachnida and the family Trombiculidae. This systematic review provides an overview of the trombiculids of clinical importance, their distribution and effects of the bite on human health. Our results show that there are different species of mites that can have important consequences for human health. No fatal cases owere registered.Even so, the transmission of scrub typhus is important and remains one of the most life-threatening rickettsial infections in some regions of Asia. Conclusions: The bite of different species of trombiculids around the world can cause a wide array of clinical consequences to human health. Even as mortality appear to be nonexistent, trombiculid bites must be adequately diagnosed and treated properly.

Abstract 1484: Microbial sequencing using a single-pool target enrichment of multiple variable regions of the 16S rRNA gene, the nuclear ribosomal internal transcribed spacer (ITS) region, and antimicrobial resistance genes

Abstract The human microbiome has been studied in the context of a number of diseases and has recently been gaining momentum in the field of cancer research. The composition of the gut microbiome, for example, has been shown to affect cancer progression and may act as both a biomarker and therapeutic target. Metagenomic shotgun sequencing has played a large role in characterizing the composition of microbial communities. However, direct sequencing of multiple complex samples in parallel has relatively low sensitivity and struggles to accurately characterize the microbiome. Alternatively, targeted PCR and sequencing can be used to simultaneously enrich for and identify multiple microbial targets of interest in parallel. Here, we present a single-pool multiplex PCR assay to enrich for multiple variable regions of the 16S ribosomal RNA (rRNA) gene, the nuclear ribosomal internal transcribed spacer (ITS) region, and 35 antibiotic resistance genes from multiple bacteria species listed as threats by the CDC. Our two-hour protocol generates target-enriched libraries from genomic DNA (gDNA) that are compatible with Illumina sequencing platforms. We validated our protocol using gDNA from mock microbial communities comprising 20 bacterial strains mixed at varied proportions. The specificity, sensitivity, and quantification of our assay was also evaluated using clinical isolates and extracts from swine manure. We found that our single-tube, target-enriched library workflow accurately and reproducibly identified genomic content from reference strains with as few as six starting genomic copies mixed in complex samples. Further, enrichment of seven variable (V) regions of the 16S rRNA gene facilitated the detection of greater diversity and improved classification of microbial communities compared to the conventionally used primer set, which only targets the V3-V4 regions. Simultaneous analysis of both the 16S rRNA gene and antibiotic resistance genes provided greater differentiation of bacterial pathogens and greater characterization of the overall structure of the community’s functional repertoire. This study highlights the power of targeted enrichment via single-pool amplification for sequencing and characterizing microbial communities, including those that have important consequences for human health. Citation Format: Kayla Peck, Robert Stedtfeld, Jordan RoseFigura, Brett Reed, Drew McUsic, Jon Irish, Brett Etchebarne, Timothy Johnson, Laurie Kurihara, Vladimir Makarov. Microbial sequencing using a single-pool target enrichment of multiple variable regions of the 16S rRNA gene, the nuclear ribosomal internal transcribed spacer (ITS) region, and antimicrobial resistance genes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1484.

An Experiment with Air Purifiers in Delhi during Winter 2015-2016.

Particulate pollution has important consequences for human health, and is an issue of global concern. Outdoor air pollution has become a cause for alarm in India in particular because recent data suggest that ambient pollution levels in Indian cities are some of the highest in the world. We study the number of particles between 0.5μm and 2.5μm indoors while using affordable air purifiers in the highly polluted city of Delhi. Though substantial reductions in indoor number concentrations are observed during air purifier use, indoor air quality while using an air purifier is frequently worse than in cities with moderate pollution, and often worse than levels observed even in polluted cities. When outdoor pollution levels are higher, on average, indoor pollution levels while using an air purifier are also higher. Moreover, the ratio of indoor air quality during air purifier use to two comparison measures of air quality without an air purifier are also positively correlated with outdoor pollution levels, suggesting that as ambient air quality worsens there are diminishing returns to improvements in indoor air quality during air purifier use. The findings of this study indicate that although the most affordable air purifiers currently available are associated with significant improvements in the indoor environment, they are not a replacement for public action in regions like Delhi. Although private solutions may serve as a stopgap, reducing ambient air pollution must be a public health and policy priority in any region where air pollution is as high as Delhi’s during the winter.

Strongly increasing heat extremes in the Middle East and North Africa (MENA) in the 21st century

The ensemble results of CMIP5 climate models that applied the RCP4.5 and RCP8.5 scenarios have been used to investigate climate change and temperature extremes in the Middle East and North Africa (MENA). Uncertainty evaluation of climate projections indicates good model agreement for temperature but much less for precipitation. Results imply that climate warming in the MENA is strongest in summer while elsewhere it is typically stronger in winter. The summertime warming extends the thermal low at the surface from South Asia across the Middle East over North Africa, as the hot desert climate intensifies and becomes more extreme. Observations and model calculations of the recent past consistently show increasing heat extremes, which are projected to accelerate in future. The number of warm days and nights may increase sharply. On average in the MENA, the maximum temperature during the hottest days in the recent past was about 43 °C, which could increase to about 46 °C by the middle of the century and reach almost 50 °C by the end of the century, the latter according to the RCP8.5 (business-as-usual) scenario. This will have important consequences for human health and society.

Chemical Genomics Identifies the PERK-Mediated Unfolded Protein Stress Response as a Cellular Target for Influenza Virus Inhibition.

ABSTRACTInfluenza A viruses generate annual epidemics and occasional pandemics of respiratory disease with important consequences for human health and the economy. Therefore, a large effort has been devoted to the development of new anti-influenza virus drugs directed to viral targets, as well as to the identification of cellular targets amenable to anti-influenza virus therapy. Here we have addressed the identification of such potential cellular targets by screening collections of drugs approved for human use. We reasoned that screening with a green fluorescent protein-based recombinant replicon system would identify cellular targets involved in virus transcription/replication and/or gene expression and hence address an early stage of virus infection. By using such a strategy, we identified Montelukast (MK) as an inhibitor of virus multiplication. MK inhibited virus gene expression but did not alter viral RNA synthesis in vitro or viral RNA accumulation in vivo. The low selectivity index of MK prevented its use as an antiviral, but it was sufficient to identify a new cellular pathway suitable for anti-influenza virus intervention. By deep sequencing of RNA isolated from mock- and virus-infected human cells, treated with MK or left untreated, we showed that it stimulates the PERK-mediated unfolded protein stress response. The phosphorylation of PERK was partly inhibited in virus-infected cells but stimulated in MK-treated cells. Accordingly, pharmacological inhibition of PERK phosphorylation led to increased viral gene expression, while inhibition of PERK phosphatase reduced viral protein synthesis. These results suggest the PERK-mediated unfolded protein response as a potential cellular target to modulate influenza virus infection.

Light at night, clocks and health: from humans to wild organisms.

The increasing use of electric lights has modified the natural light environment dramatically, posing novel challenges to both humans and wildlife. Indeed, several biomedical studies have linked artificial light at night to the disruption of circadian rhythms, with important consequences for human health, such as the increasing occurrence of metabolic syndromes, cancer and reduced immunity. In wild animals, light pollution is associated with changes in circadian behaviour, reproduction and predator-prey interactions, but we know little about the underlying physiological mechanisms and whether wild species suffer the same health problems as humans. In order to fill this gap, we advocate the need for integrating ecological studies in the field, with chronobiological approaches to identify and characterize pathways that may link temporal disruption caused by light at night and potential health and fitness consequences.

Regulation of influenza virus infection by long non-coding RNAs

Influenza A viruses generate annual epidemics and occasional pandemics of respiratory disease with important consequences for human health and economy. To establish a productive infection, influenza viruses interact with cellular factors to favour their own replication and to suppress antiviral cell responses. Although most virus-host interaction studies have been centred on cell protein factors, most of the human transcriptome comprises non-coding RNAs, as miRNAs and lncRNAs. The latter are key cellular regulators in many cellular processes, including transcriptional and post-transcriptional regulation. Influenza virus infection induces the differential expression of hundreds of potential lncRNAs, some of which are related to the antiviral pathways activated by the cell while others may be deregulated by the infection to allow efficient virus multiplication. Although our knowledge on the role of cellular lncRNAs for influenza virus replication and pathogenesis is still at its infancy, several lncRNAs have been described to influence the cell innate response to the virus by altering the histone modification at specific sites, by interaction with specific transcription factors or directly stimulating in cis the expression of specific IFN-induced genes. In addition, at least one lncRNA appears to be required for virus multiplication in an IFN-independent way.

Fitness Trade-offs Restrict the Evolution of Resistance to Amphotericin B

Author SummaryThe evolution of drug resistance in human pathogens is considered an inevitable consequence of the selective pressures imposed by antimicrobial drugs. Yet resistance to one antifungal drug, amphotericin B (AmB), remains extremely rare despite decades of widespread use. Here we explore the biological mechanisms underlying this conundrum. By examining natural and experimental populations of Candida albicans, we identify multiple mutations that confer resistance to AmB in vitro. As with the evolution of resistance to other antifungals, we find that the chaperone protein Hsp90 is involved in enabling the evolution of resistance to AmB. We also discover, however, that mutations that confer AmB resistance impose massive costs on other aspects of fungal pathogenicity; strains that are resistant to AmB are hypersensitive to attack by the host immune system and are unable to invade and damage host tissue. Thus, the evolution of resistance to AmB is restricted by a tradeoff between tolerance of the drug and the ability to cause disease. We propose that developing new antibiotics for which resistance presents such dire tradeoffs may be a promising strategy to prevent the evolution of resistance.

Strain-Specific Transfer of Antibiotic Resistance from an Environmental Plasmid to Foodborne Pathogens

Pathogens resistant to multiple antibiotics are rapidly emerging, entailing important consequences for human health. This study investigated if the broad-host-range multiresistance plasmid pB10, isolated from a wastewater treatment plant, harbouring amoxicillin, streptomycin, sulfonamide, and tetracycline resistance genes, was transferable to the foodborne pathogens Salmonella spp. or E. coli O157:H7 and how this transfer alters the phenotype of the recipients. The transfer ratio was determined by both plating and flow cytometry. Antibiotic resistance profiles were determined for both recipients and transconjugants using the disk diffusion method. For 14 of the 15 recipient strains, transconjugants were detected. Based on plating, transfer ratios were between 6.8 × 10−9 and 3.0 × 10−2 while using flow cytometry, transfer ratios were between <1.0 × 10−5 and 1.9 × 10−2. With a few exceptions, the transconjugants showed phenotypically increased resistance, indicating that most of the transferred resistance genes were expressed. In summary, we showed that an environmental plasmid can be transferred into foodborne pathogenic bacteria at high transfer ratios. However, the transfer ratio seemed to be recipient strain dependent. Moreover, the newly acquired resistance genes could turn antibiotic susceptible strains into resistant ones, paving the way to compromise human health.

Innoversity in knowledge-for-action and adaptation to climate change: the first steps of an 'evidence-based climatic health' transfrontier training program.

It has become increasingly clear to the international scientific community that climate change is real and has important consequences for human health. To meet these new challenges, the World Health Organization recommends reinforcing the adaptive capacity of health systems. One of the possible avenues in this respect is to promote awareness and knowledge translation in climatic health, at both the local and global scales. Within such perspective, two major themes have emerged in the field of public health research: 1) the development of advanced training adapted to ‘global environment’ change and to the specific needs of various groups of actors (doctors, nurses, public health practitioners, health care managers, public service managers, local communities, etc) and 2) the development of strategies for implementing research results and applying various types of evidence to the management of public health issues affected by climate change. Progress on these two fronts will depend on maximum innovation in transdisciplinary and transsectoral collaborations. The general purpose of this article is to present the program of a new research and learning chair designed for this double set of developmental objectives – a chair that emphasizes ‘innoversity’ (the dynamic relationship between innovation and diversity) and ‘transfrontier ecolearning for adaptive actions’. The Écoapprentissages, santé mentale et climat collaborative research chair (University of Montreal and Quebec National Public Health Institute) based in Montreal is a center for ‘transdisciplinary research’ on the transfrontier knowledge-for-action that can aid adaptation of the public health sector, the public mental health sector, and the public service sector to climate change, as well as a center for complex collaborations on evidence-based climatic health ‘training’. This program-focused article comprises two main sections. The first section presents the ‘general’ and ‘specific contexts’ in which the chair emerged. The ‘general context’ pertains to the health-related challenge of finding ways to integrate, transfer, and implement knowledge, a particularly pointed challenge in Canada. The ‘specific context’ refers to the emerging research field of adaptation of public health to climate change. In the second section, the characteristics of the research chair are more extensively detailed (the vision of ‘innoversity’ and ‘ transfrontier knowledge-for-action,’ the approach of shared responsibility and complex collaboration, objectives, and major axes of research). We conclude with a call for complex collaboration toward knowledge-for-action in public health services/mental health services/public services’ adaptation to climate change: this call is aimed at individual and institutional actors in the North and South/West and East concerned by these issues.

A Tissue-Specific Atlas of Mouse Protein Phosphorylation and Expression

Although most tissues in an organism are genetically identical, the biochemistry of each is optimized to fulfill its unique physiological roles, with important consequences for human health and disease. Eachtissue's unique physiology requires tightly regulated gene and protein expression coordinated by specialized, phosphorylation-dependent intracellular signaling. To better understand the role of phosphorylation in maintenance of physiological differences among tissues, we performed proteomic and phosphoproteomic characterizations of nine mouse tissues. We identified 12,039 proteins, including 6296 phosphoproteins harboring nearly 36,000 phosphorylation sites. Comparing protein abundances and phosphorylation levels revealed specialized, interconnected phosphorylation networks within each tissue while suggesting that many proteins are regulated by phosphorylation independently of their expression. Our data suggest that the "typical" phosphoprotein is widely expressed yet displays variable, often tissue-specific phosphorylation that tunes protein activity to the specific needs of each tissue. We offer this dataset as an online resource for the biological research community.

F-pili dynamics by live-cell imaging

Bacteria have evolved numerous mechanisms for cell-cell communication, many of which have important consequences for human health. Among these is conjugation, the direct transfer of DNA from one cell to another. For gram-negative bacteria, conjugation requires thin, flexible filaments (conjugative pili) that are elaborated by DNA donor cells. The structure, function, and especially the dynamics of conjugative pili are poorly understood. Here, we have applied live-cell imaging to characterize the dynamics of F-pili (conjugative pili encoded by the F plasmid of Escherichia coli). We establish that F-pili normally undergo cycles of extension and retraction in the absence of any obvious triggering event, such as contact with a recipient cell. When made, such contacts are able to survive the shear forces felt by bacteria in liquid media. Our data emphasize the role of F-pilus flexibility both in efficiently sampling a large volume surrounding donor cells in liquid culture and in establishing and maintaining cell-cell contact. Additionally and unexpectedly, we infer that extension and retraction are accompanied by rotation about the long axis of the filament.

Asia: Changing Times and Changing Problems

Asia: Changing Times and Changing Problems

The effects on human health from stratospheric ozone depletion and its interactions with climate change

Ozone depletion leads to an increase in the ultraviolet-B (UV-B) component (280-315 nm) of solar ultraviolet radiation (UVR) reaching the surface of the Earth with important consequences for human health. Solar UVR has many harmful and some beneficial effects on individuals and, in this review, information mainly published since the previous report in 2003 (F. R. de Gruijl, J. Longstreth, M. Norval, A. P. Cullen, H. Slaper, M. L. Kripke, Y. Takizawa and J. C. van der Leun, Photochem. Photobiol. Sci., 2003, 2, pp. 16-28) is discussed. The eye is exposed directly to sunlight and this can result in acute or long-term damage. Studying how UV-B interacts with the surface and internal structures of the eye has led to a further understanding of the location and pathogenesis of a number of ocular diseases, including pterygium and cataract. The skin is also exposed directly to solar UVR, and the development of skin cancer is the main adverse health outcome of excessive UVR exposure. Skin cancer is the most common form of malignancy amongst fair-skinned people, and its incidence has increased markedly in recent decades. Projections consistently indicate a further doubling in the next ten years. It is recognised that genetic factors in addition to those controlling pigment variation can modulate the response of an individual to UVR. Several of the genetic factors affecting susceptibility to the development of squamous cell carcinoma, basal cell carcinoma and melanoma have been identified. Exposure to solar UVR down-regulates immune responses, in the skin and systemically, by a combination of mechanisms including the generation of particularly potent subsets of T regulatory cells. Such immunosuppression is known to be a crucial factor in the generation of skin cancers. Apart from a detrimental effect on infections caused by some members of the herpesvirus and papillomavirus families, the impact of UV-induced immunosuppression on other microbial diseases and vaccination efficacy is not clear. One important beneficial effect of solar UV-B is its contribution to the cutaneous synthesis of vitamin D, recognised to be a crucial hormone for bone health and for other aspects of general health. There is accumulating evidence that UVR exposure, either directly or via stimulation of vitamin D production, has protective effects on the development of some autoimmune diseases, including multiple sclerosis and type 1 diabetes. Adequate vitamin D may also be protective for the development of several internal cancers and infections. Difficulties associated with balancing the positive effects of vitamin D with the negative effects of too much exposure to solar UV-B are considered. Various strategies that can be adopted by the individual to protect against excessive exposure of the eye or the skin to sunlight are suggested. Finally, possible interactions between ozone depletion and climate warming are outlined briefly, as well as how these might influence human behaviour with regard to sun exposure.

Quantifying the urban environment: A scale measure of urbanicity outperforms the urban–rural dichotomy

The rapid urbanization of the developing world has important consequences for human health. Although several authorities have called for better research on the relationships between urbanicity and health, most researchers still use a poor measurement of urbanicity, the urban–rural dichotomy. Our goal was to construct a scale of urbanicity using community level data from the Cebu Longitudinal Health and Nutrition Survey. We used established scale development methods to validate the new measure and tested its performance against the dichotomy. The new scale illustrated misclassification by the urban–rural dichotomy, and was able to detect differences in urbanicity, both between communities and across time, that were not apparent before. Furthermore, using a continuous measure of urbanicity allowed for better illustrations of the relationships between urbanicity and health. The new scale is a better measure of urbanicity than the traditionally used urban–rural dichotomy.

Mucin Granule Intraluminal Organization

Mucus secretions have played a central role in the evolution of multicellular organisms, enabling adaptation to widely differing environments. In vertebrates, mucus covers and protects the epithelial cells in the respiratory, gastrointestinal, urogenital, visual, and auditory systems, amphibian's epidermis, and the gills in fishes. Deregulation of mucus production and/or composition has important consequences for human health. For example, mucus obstruction of small airways is observed in chronic airway diseases, including chronic obstructive pulmonary disease, asthma, and cystic fibrosis. The major protein component in the mucus is a family of large, disulfide-bonded glycoproteins known as gel-forming mucins. These proteins are accumulated in large, regulated secretory granules (the mucin granules) that occupy most of the apical cytoplasm of specialized cells known as mucous/goblet cells. Since mucin oligomers have contour dimensions larger than the mucin granule average diameter, the question arises how these highly hydrophilic macromolecules are organized within these organelles. I review here the intraluminal organization of the mucin granule in view of our knowledge on the structure, biosynthesis, and biophysical properties of gel-forming mucins, and novel imaging studies in living mucous/goblet cells. The emerging concept is that the mucin granule lumen comprises a partially condensed matrix meshwork embedded in a fluid phase where proteins slowly diffuse.

Pollen production by Pinus taeda growing in elevated atmospheric CO2

Summary 1Rising concentrations of atmospheric CO2 may have important consequences for reproductive allocation in forest trees. Changes in pollen production could influence population dynamics and is likely to have important consequences for human health. This is the first study to evaluate pollen production by forest trees in response to rising atmospheric CO2. 2Our research objective was to quantify pollen production by Loblolly Pine (Pinus taeda L.) trees growing in elevated CO2 (ambient + 200 µl l−1) since 1996. 3Trees grown in high-CO2 plots first began producing pollen while younger and at smaller sizes relative to ambient-grown trees. Pollen cone and airborne pollen grain abundances were significantly greater in the fumigated stands. We conclude that the greater number of mature trees in high-CO2 plots resulted in greater pollen production at the stand level. 4Precocious pollen production has important implications for fertilization and pollen dispersal from young, dense stands. Increasing levels of airborne pollen raise concerns for escalating rates of human respiratory disease.

Biology of Plant Rhabdoviruses

The Rhabdoviridae, whose members collectively infect invertebrates, animals, and plants, form a large family that has important consequences for human health, agriculture, and wildlife ecology. Plant rhabdoviruses can be separated into the genera Cytorhabdovirus and Nucleorhabdovirus, based on their sites of replication and morphogenesis. This review presents a general overview of classical and contemporary findings about rhabdovirus ecology, pathology, vector relations, and taxonomy. The genome organization and structure of several recently sequenced nucleorhabdoviruses and cytorhabdoviruses is integrated with new cell biology findings to provide a model for the replication of the two genera. A prospectus outlines the exciting opportunities for future research that will contribute to a more detailed understanding of the biology, biochemistry, replication and host interactions of the plant rhabdoviruses.