Influences of sea level changes and volcanic eruptions on Holocene vegetation in Tonga

Here, we investigate Mid- to Late-Holocene vegetation changes in low-lying coastal areas in Tonga and how changing sea levels and recurrent volcanic eruptions have influenced vegetation dynamics on four islands of the Tongan archipelago (South Pacific). To investigate past vegetation and environmental change at Ngofe Marsh (‘Uta Vava’u), we examined palynomorphs (pollen and spores), charcoal (fire), and sediment characteristics (volcanic activity) from a 6.7-m-long sediment core. Radiocarbon dating indicated the sediments were deposited over the last 7700 years. We integrated the Ngofe Marsh data with similar previously published data from Avai’o’vuna Swamp on Pangaimotu Island, Lotofoa Swamp on Foa Island, and Finemui Swamp on Ha’afeva Island. Plant taxa were categorized as littoral, mangrove, rainforest, successional/ disturbance, and wetland groups, and linear models were used to examine relationships between vegetation, relative sea level change, and volcanic eruptions (tephra). We found that relative sea level change has impacted vegetation on three of the four islands investigated. Volcanic eruptions were not identified as a driver of vegetation change. Rainforest decline does not appear to be driven by sea level changes or volcanic eruptions. From all sites analyzed, vegetation at Finemui Swamp was most sensitive to changes in relative sea level. While vegetation on low-lying Pacific islands is sensitive to changing sea levels, island characteristics, such as area and elevation, are also likely to be important factors that mediate specific island responses to drivers of change.     

The influence of life history and climate driven diversification on the mtDNA phylogeographic structures of two southern African Mastomys species (Rodentia: Muridae: Murinae)

The phylogeographic patterns of small mammals in southern Africa are frequently disjunct. This pattern is predominately attributed to vicariant geographical barriers coupled to climate driven diversification. To gain further insights into this hypothesis, we embarked on a comparative mtDNA phylogeographic study of two common rodent species in southern Africa, Mastomys natalensis and Mastomys coucha. Parsimony haplotype networks and SplitsTrees of mtDNA cytochrome oxidase I data showed a large degree of haplotype sharing throughout the sampling range. Within southern Africa, we found no conclusive evidence to support geographic vicariance as a contributing factor towards Mastomys speciation. We proposed that the regional phylogeographic structures detected for M. natalensis and M. coucha are the result of weak isolation by distance coupled to repeated expansions and contractions of suitable habitat. Both species probably survived in multiple refugia during unfavourable periods and mismatch distributions show signs of population expansion. Mitochondrial DNA nucleotide diversity values (π) show marked differences between the two species (M. natalensis: 0.003 and M. coucha: 0.468), and M. coucha also shows a higher level of population differentiation in AMOVA analyses. These differences are most likely due to life history discrepancies between the two species. Mastomys coucha is regarded to be more of a habitat specialist when compared to M. natalensis, and this probably places a higher constraint on M. coucha dispersal abilities. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 114 , 58–68.     

Identification of the minimal protein domain required for priming activity of Munc13-1

Most nerve cells communicate with each other through synaptic transmission at chemical synapses. The regulated exocytosis of neurotransmitters, hormones, and peptides occurs at specialized membrane areas through Ca2+-triggered fusion of secretory vesicles with the plasma membrane . Prior to fusion, vesicles are docked at the plasma membrane and must then be rendered fusion-competent through a process called priming. The molecular mechanism underlying this priming process is most likely the formation of the SNARE complex consisting of Syntaxin 1, SNAP-25, and Synaptobrevin 2. Members of the Munc13 protein family consisting of Munc13-1, -2, -3, and -4 were found to be absolutely required for this priming process . In the present study, we identified the minimal Munc13-1 domain that is responsible for its priming activity. Using Munc13-1 deletion constructs in an electrophysiological gain-of-function assay of chromaffin-granule secretion, we show that priming activity is mediated by the C-terminal residues 1100-1735 of Munc13-1, which contains both Munc13-homology domains and the C-terminal C2 domain. Priming by Munc13-1 appears to require its interaction with Syntaxin 1 because point mutants that do not bind Syntaxin 1 do not prime chromaffin granules.     

Do Strategies to Improve Quality of Maternal and Child Health Care in Lower and Middle Income Countries Lead to Improved Outcomes? A Review of the Evidence

Objectives

Efforts to scale-up maternal and child health services in lower and middle income countries will fail if services delivered are not of good quality. Although there is evidence of strategies to increase the quality of health services, less is known about the way these strategies affect health system goals and outcomes. We conducted a systematic review of the literature to examine this relationship.

Methods

We undertook a search of MEDLINE, SCOPUS and CINAHL databases, limiting the results to studies including strategies specifically aimed at improving quality that also reported a measure of quality and at least one indicator related to health system outcomes. Variation in study methodologies prevented further quantitative analysis; instead we present a narrative review of the evidence.

Findings

Methodologically, the quality of evidence was poor, and dominated by studies of individual facilities. Studies relied heavily on service utilisation as a measure of strategy success, which did not always correspond to improved quality. The majority of studies targeted the competency of staff and adequacy of facilities. No strategies addressed distribution systems, public-private partnership or equity. Key themes identified were the conflict between perceptions of patients and clinical measures of quality and the need for holistic approaches to health system interventions.

Conclusion

Existing evidence linking quality improvement strategies to improved MNCH outcomes is extremely limited. Future research would benefit from the inclusion of more appropriate indicators and additional focus on non-facility determinants of health service quality such as health policy, supply distribution, community acceptability and equity of care.     

Monitoring growth phase-related changes in phosphatidylcholine-specific phospholipase C production,adhesion properties and physiology of <Emphasis Type="Italic">Bacillus cereus</Emphasis> vegetative cells

The physiological status and metabolic heterogeneity of Bacillus cereus cells within a culture during an 8-h batch fermentation process was measured using flow cytometry (FCM). Concurrently, production of the toxin, PC-PLC, and the extent of cell adhesion of live and dead cells were monitored using novel fluorescent assays. Flow cytometry analysis detected growth phase-related changes in the physiological profiles of cells over the course of the fermentation, with variation in the percentage of cells displaying membrane damage and intracellular esterase and redox activities. As the exponential phase proceeded, populations became more uniform in terms of protein content as measured using FCM in tandem with a cell tracking dye, with the majority of cells becoming membrane intact, esterase positive and redox active. PC-PLC activity appeared strongly related to cell density. Permeabilisation of cells was accompanied by a loss in adherent properties, while 25–100% of cells with intracellular esterase activity possessed adhesion properties. Cells in late exponential phase appeared to have reduced adherence properties compared to cells in early exponential or lag phase. As well as demonstrating the utility of FCM for measuring heterogeneity in terms of cell physiological status throughout the course of batch cultures, the methods utilised in this study could be used to relate processes such as toxin production or cell adhesion to cell physiological state.     

Heterologous expression of the plant cysteine protease bromelain and its inhibitor in Pichia pastoris

Expression of proteases in heterologous hosts remains an ambitious challenge due to severe problems associated with digestion of host proteins. On the other hand, proteases are broadly used in industrial applications and resemble promising drug candidates. Bromelain is an herbal drug that is medicinally used for treatment of oedematous swellings and inflammatory conditions and consists in large part of proteolytic enzymes. Even though various experiments underline the requirement of active cysteine proteases for biological activity, so far no investigation succeeded to clearly clarify the pharmacological mode of action of bromelain. The potential role of proteases themselves and other molecules of this multi‐component extract currently remain largely unknown or ill defined. Here, we set out to express several bromelain cysteine proteases as well as a bromelain inhibitor molecule in order to gain defined molecular entities for subsequent studies. After cloning the genes from its natural source Ananas comosus (pineapple plant) into Pichia pastoris and subsequent fermentation and purification, we obtained active protease and inhibitor molecules which were subsequently biochemically characterized. Employing purified bromelain fractions paves the way for further elucidation of pharmacological activities of this natural product. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:54–65, 2017     

Inflorescence architecture: A developmental genetics approach

We are characterizing a suiteof Pisum sativum mutants that alter inflorescence architecture to construct a model for the genetic regulation of inflorescence development in a plant with a compound raceme. Such a model, when compared with those created forAntirrhinum majus andArabidopsis thaliana, both of which have simple racemes, should provide insight into the evolution of the development of inflorescence architecture. The highly conserved nature of cloned genes that regulate reproductive development in plants and the morphological similarities among our mutants and those identified inA. majus andA. thaliana enhance the probability that a developmental genetics approach will be fruitful. Here we describe sixP. sativum mutants that affect morphologically and architecturally distinct aspects of the inflorescence, and we analyze interactions among these genes. Both vegetative and inflorescence growth of the primary axis is affected byUNIFOLIA TA, which is necessary for the function ofDETERMINATE (DET).DET maintains indeterminacy in the first-order axis. In its absence, the meristem differentiates as a stub covered with epidermal hairs.DET interacts withVEGETATIVE1 (VEG1).VEG1 appears essential for second-order inflorescence (I₂) development.veg1 mutants fail to flower or differentiate the I₂ meristem into a rudimentary stub,det veg1 double mutants produce true terminal flowers with no stubs, indicating that two genes must be eliminated for terminal flower formation inP. sativum, whereas elimination of a single gene accomplishes this inA. thaliana andA. majus. NEPTUNE also affects I₂ development by limiting to two the number of flowers produced prior to stub formation. Its role is independent ofDET, as indicated by the additive nature of the double mutantdet nep. UNI, BROC, and PIM all play roles in assigning floral meristem identity to the third-order branch.pim mutants continue to produce inflorescence branches, resulting in a highly complex architecture and aberrant flowers.uni mutants initiate a whorl of sepals, but floral organogenesis is aberrant beyond that developmental point, and the double mutantuni pim lacks identifiable floral organs. A wild-type phenotype is observed inbroc plants, butbroc enhancesthe pim phenotype in the double mutant, producing inflorescences that resemble broccoli. Collectively these genes ensure that only the third-order meristem, not higher- or lower-order meristems, generates floral organs, thus precisely regulating the overall architecture of the plant. Gene symbols used in this article: For clarity a common symbolization is used for genes of all species discussed in this article. Genes are symbolized with italicized capital letters. Mutant alleles are represented by lowercase, italicized letters. In both cases, the number immediately following the gene symbol differentiates among genes with the same symbol. If there are multiple alleles, a hyphen followed by a number is used to distinguish alleles. Protein products are represented by capital letters without italics.     

Chlamydia pneumoniae Hides inside Apoptotic Neutrophils to Silently Infect and Propagate in Macrophages

Background

Intracellular pathogens have developed elaborate strategies for silent infection of preferred host cells. Chlamydia pneumoniae is a common pathogen in acute infections of the respiratory tract (e.g. pneumonia) and associated with chronic lung sequelae in adults and children. Within the lung, alveolar macrophages and polymorph nuclear neutrophils (PMN) are the first line of defense against bacteria, but also preferred host phagocytes of chlamydiae.

Methodology/Principal Findings

We could show that C. pneumoniae easily infect and hide inside neutrophil granulocytes until these cells become apoptotic and are subsequently taken up by macrophages. C. pneumoniae infection of macrophages via apoptotic PMN results in enhanced replicative activity of chlamydiae when compared to direct infection of macrophages, which results in persistence of the pathogen. Inhibition of the apoptotic recognition of C. pneumoniae infected PMN using PS- masking Annexin A5 significantly lowered the transmission of chlamydial infection to macrophages. Transfer of apoptotic C. pneumoniae infected PMN to macrophages resulted in an increased TGF-ß production, whereas direct infection of macrophages with chlamydiae was characterized by an enhanced TNF-α response.

Conclusions/Significance

Taken together, our data suggest that C. pneumoniae uses neutrophil granulocytes to be silently taken up by long-lived macrophages, which allows for efficient propagation and immune protection within the human host.