Influenza H5N1 virus infection of polarized human alveolar epithelial cells and lung microvascular endothelial cells

Background

Highly pathogenic avian influenza (HPAI) H5N1 virus is entrenched in poultry in Asia and Africa and continues to infect humans zoonotically causing acute respiratory disease syndrome and death. There is evidence that the virus may sometimes spread beyond respiratory tract to cause disseminated infection. The primary target cell for HPAI H5N1 virus in human lung is the alveolar epithelial cell. Alveolar epithelium and its adjacent lung microvascular endothelium form host barriers to the initiation of infection and dissemination of influenza H5N1 infection in humans. These are polarized cells and the polarity of influenza virus entry and egress as well as the secretion of cytokines and chemokines from the virus infected cells are likely to be central to the pathogenesis of human H5N1 disease.

Aim

To study influenza A (H5N1) virus replication and host innate immune responses in polarized primary human alveolar epithelial cells and lung microvascular endothelial cells and its relevance to the pathogenesis of human H5N1 disease.

Methods

We use an in vitro model of polarized primary human alveolar epithelial cells and lung microvascular endothelial cells grown in transwell culture inserts to compare infection with influenza A subtype H1N1 and H5N1 viruses via the apical or basolateral surfaces.

Results

We demonstrate that both influenza H1N1 and H5N1 viruses efficiently infect alveolar epithelial cells from both apical and basolateral surface of the epithelium but release of newly formed virus is mainly from the apical side of the epithelium. In contrast, influenza H5N1 virus, but not H1N1 virus, efficiently infected polarized microvascular endothelial cells from both apical and basolateral aspects. This provides a mechanistic explanation for how H5N1 virus may infect the lung from systemic circulation. Epidemiological evidence has implicated ingestion of virus-contaminated foods as the source of infection in some instances and our data suggests that viremia, secondary to, for example, gastro-intestinal infection, can potentially lead to infection of the lung. HPAI H5N1 virus was a more potent inducer of cytokines (e.g. IP-10, RANTES, IL-6) in comparison to H1N1 virus in alveolar epithelial cells, and these virus-induced chemokines were secreted onto both the apical and basolateral aspects of the polarized alveolar epithelium.

Conclusion

The predilection of viruses for different routes of entry and egress from the infected cell is important in understanding the pathogenesis of influenza H5N1 infection and may help unravel the pathogenesis of human H5N1 disease.     

Epidemiologic characteristics of human campylobacteriosis in the County Primorsko-goranska (Croatia), 2003-2007

The aim of the study was to investigate campylobacteriosis incidence in the County Primorsko-goranska (Croatia) between 2003 and 2007 and to find out possible connection with environmental factors (the average monthly temperature and total monthly precipitation). The data (number of stool samples examined, age and sex distribution of patients, monthly distribution of isolates and distribution of isolates according to the species) from the Laboratory for Diagnostics of Enteric Infections of the Teaching Institute of Public Health of the County Primorsko-goranska (Croatia) were analyzed retrospectively. During the observed period 30,164 stool samples were examined for Campylobacter spp. Campylobacters were identified in 1,242 (4.12%) samples. The overall annual campylobacter incidence rate was 81.3 +/- 21.9/100,000 population. Campylobacter jejuni was found in 1,093 (88%) and C. coli in 149 (12%) patients. Our findings showed age distribution of patients typical for developed countries. The patients were mostly children under 5 years (484.4 +/- 129.1/ 100,000, p < 0.001) and between 5 and 9 years of age (226.5 +/- 60.5/100,000, p < 0.05). Male consistently experienced higher rates, but the difference between genders was significant in the age groups from birth till late twentieth (p < 0.001). Campylobacter rates were significantly associated with monthly average temperatures (p < 0.05), but not with precipitation. Further investigations into the incidence of campylobacteriosis on the national level are necessary. The causes of the noticed monthly distribution, sources of infection and connection with the routes of transmission in humans need to be elucidated as well.     

Four Decades of Forest Persistence,Clearance and Logging on Borneo

The native forests of Borneo have been impacted by selective logging, fire, and conversion to plantations at unprecedented scales since industrial-scale extractive industries began in the early 1970s. There is no island-wide documentation of forest clearance or logging since the 1970s. This creates an information gap for conservation planning, especially with regard to selectively logged forests that maintain high conservation potential. Analysing LANDSAT images, we estimate that 75.7% (558,060 km²) of Borneo''s area (737,188 km²) was forested around 1973. Based upon a forest cover map for 2010 derived using ALOS-PALSAR and visually reviewing LANDSAT images, we estimate that the 1973 forest area had declined by 168,493 km² (30.2%) in 2010. The highest losses were recorded in Sabah and Kalimantan with 39.5% and 30.7% of their total forest area in 1973 becoming non-forest in 2010, and the lowest in Brunei and Sarawak (8.4%, and 23.1%). We estimate that the combined area planted in industrial oil palm and timber plantations in 2010 was 75,480 km², representing 10% of Borneo. We mapped 271,819 km of primary logging roads that were created between 1973 and 2010. The greatest density of logging roads was found in Sarawak, at 0.89 km km⁻², and the lowest density in Brunei, at 0.18 km km⁻². Analyzing MODIS-based tree cover maps, we estimate that logging operated within 700 m of primary logging roads. Using this distance, we estimate that 266,257 km² of 1973 forest cover has been logged. With 389,566 km² (52.8%) of the island remaining forested, of which 209,649 km² remains intact. There is still hope for biodiversity conservation in Borneo. Protecting logged forests from fire and conversion to plantations is an urgent priority for reducing rates of deforestation in Borneo.     

A metaproteomic approach gives functional insights into anaerobic digestion

Aims: The objective of this work was to provide functional evidence of key metabolic pathways important for anaerobic digestion processes through the identification of highly expressed proteins in a mixed anaerobic microbial consortium. Methods and Results: The microbial communities from an anaerobic industrial‐like wastewater treatment bioreactor were characterized using phylogenetic analyses and metaproteomics. Clone libraries indicated that the bacterial community in the bioreactor was diverse while the archaeal population was mainly composed of Methanocorpusculum‐like (76%) micro‐organisms. Three hundred and eighty‐eight reproducible protein spots were obtained on 2‐D gels, of which 70 were excised and 33 were identified. The putative functions of the proteins detected in the anaerobic bioreactor were related to cellular processes, including methanogenesis from CO₂ and acetate, glycolysis and the pentose phosphate pathway. Metaproteomics also indicated, by protein assignment, the presence of specific micro‐organisms in the bioreactor. However, only a limited overlap was observed between the phylogenetic and metaproteomic analyses. Conclusions: This study provides some direct evidence of the microbial activities taking place during anaerobic digestion. Significance and Impact of Study: This study demonstrates metaproteomics as a useful tool to uncover key biochemical pathways underpinning specific anaerobic bioprocesses.     

Identification of an S-locus glycoprotein allele introgressed from B. napus ssp. rapifera to B. napus ssp. oleifera.

We have previously described a developmentally regulated mRNA in maize that accumulates in mature embryos and is involved in a variety of stress responses in the plant. The sequence of the encoded 16 kDa protein (MA16) predicts that it is an RNA-binding protein, since it possesses a ribonucleoprotein consensus sequence-type RNA-binding domain (CS-RBD). To assess the predicted RNA binding property of the protein and as a starting point to characterize its function we have used ribohomopolymer-binding assays. Here we show that the MA16-encoded protein binds preferentially to uridine- and guanosine-rich RNAs. In light of these results a likely role for this protein in RNA metabolism during late embryogenesis and in the stress response is discussed.