The superior folding of a RANTES analogue expressed in lactobacilli as compared to mammalian cells reveals a promising system to screen new RANTES mutants

Development of effective topical microbicides for the prevention of HIV-1 sexual transmission represents a primary goal for the control of the AIDS pandemic. The viral coreceptor CCR5, used by the vast majority of primary HIV-1 isolates, is considered a primary target molecule. RANTES and its derivatives are the most suitable protein-based compounds to fight HIV-1 via CCR5 targeting. Yet, receptor activation should be avoided to prevent pro-inflammatory effects and possibly provide anti-inflammatory properties. C1C5 RANTES is a chemokine mutant that exhibits high anti-HIV-1 potency coupled with CCR5 antagonism. However, the need for the formation of an N-terminal intramolecular disulfide bridge between non-natural cysteine residues at positions 1 and 5 represents a challenge for the correct folding of this protein in recombinant expression systems, a crucial step towards its development as a microbicide against HIV-1. We report here a rare case of superior folding in a prokaryote as compared to an eukaryotic expression system. Production of C1C5 RANTES was highly impaired in CHO cells, with a dramatic yield reduction compared to that of wild type RANTES and secretion of the molecule as disulfide-linked dimer. Conversely, a human vaginal isolate of Lactobacillus jensenii engineered to secrete C1C5 RANTES provided efficient delivery of the monomeric protein. This and other reports on successful secretion of complex proteins indicate that lactic acid bacteria are an excellent system for the expression of therapeutic proteins, which can be used as a platform for the engineering of conceptually novel RANTES mutants with potent anti-HIV-1 activity.     

Spatial and temporal variations of assemblages in a Mediterranean coralligenous reef and relationships with surface orientation

The structure, distribution, and temporal changes of epibenthic assemblages of a Mediterranean coralligenous reef were investigated using a multifactorial sampling design. The distribution of taxa on vertical walls and down-facing surfaces of overhangs and crevices was analysed at ten sites along 2 km of rocky reefs, south of Livorno (Ligurian Sea, Italy). The temporal variations were analysed between two periods (1995–1996 and 1997–1998) and among four sampling times within each period. Most of the space was dominated by prostrate seaweeds (including Peyssonnelia rubra, P. rosa-marina, and Mesophyllum lichenoides), turf-forming seaweeds, and the red coral Corallium rubrum. The cover of a variety of other invertebrates, mainly sponges and bryozoans, was less than 2%. All taxa were found on both vertical and down-facing surfaces. However, seaweeds dominated the vertical surfaces (mean cover >97%), while C. rubrum and other invertebrates dominated down-facing surfaces (mean density of C. rubrum >16 colonies dm⁻²). Although there was some fluctuation in the abundance of taxa, no obvious patterns were observed. These results support the model of limited temporal variability in Mediterranean coralligenous reefs, possibly related to the slow growth rates of the most abundant taxa and the reduced seasonality of physical conditions.     

An association study of cyclase-associated protein 2 and frailty

Frailty is a geriatric syndrome that results from multisystem impairment caused by age-associated accumulation of deficits. The frailty index is used to define the level of frailty. Several studies have searched for molecular biomarkers associated with frailty, to meet the needs for personalized care. Cyclase-associated protein 2 (CAP2) is a multifunctional actin-binding protein involved in various physiological and pathological processes, that might reflect frailty's intrinsic complexity. This study aimed to investigate the association between frailty index and circulating CAP2 concentration in 467 community-dwelling older adults (median age: 79; range: 65–92 years) from Milan, Italy. The selected robust regression model showed that circulating CAP2 concentration was not associated with chronological age, as well as sex and education. However, circulating CAP2 concentration was significantly and inversely associated with the frailty index: a 0.1-unit increase in frailty index leads to ~0.5-point mean decrease in CAP2 concentration. Furthermore, mean CAP2 concentration was significantly lower in frail participants (i.e., frailty index ≥0.25) than in non-frail participants. This study shows the association between serum CAP2 concentration and frailty status for the first time, highlighting the potential of CAP2 as a biomarker for age-associated accumulation of deficits.     

Palaeoenvironments of the Buia Homo site: High-resolution facies analysis and non-marine sequence stratigraphy in the Alat formation (Pleistocene Dandiero Basin, Danakil depression, Eritrea)

The Early to Middle Pleistocene Dandiero rift basin is located near the Buia village, 110 km south of Massawa (Eritrea), and is filled by about 1000 m of continental deposits bearing 1 My erectus-like human remains. The basin fill consists of six formations (from bottom up): Bukra sand and gravels (fluvial), Alat formation (fluvio-lacustrine), Wara sand and gravel (fluvial), Goreya formation (lacustrine), Aro sand (fluvio-deltaic) and Addai fanglomerate (alluvial fan). This paper is focused on the Homo-bearing deposits of the Alat formation. The Alat formation records several episodes of changing accommodation space, with repeated shifts from fluvial to lacustrine conditions. The first episode points to rapid lake formation followed by a progressive shallowing. The second episode records fluvial aggradation above a sequence boundary, followed by the development and progressive infill of a second lake. The third episode points to a rapid lake formation followed by deposition of deltaic and fluvial sediments. The last episode is characterised by fluvial deposition under low-accommodation conditions. The development of the lacustrine environments was probably controlled by tectonics, in accordance with its formation during regionally dry climatic conditions, although minor shifts toward wetter conditions cannot be excluded. Human remains occur in the upper Alat formation, where the transition from a deltaic to alluvial setting is characterised by high frequency, potentially millennial-scale, lake-level oscillations. The palaeoanthropological record in the Buia area seems to be correlated with water availability (lacustrine coastal plains and floodplains) in a relatively open and grassy environment (grassland- and savannah-dominated). The increase in fluvial discharge that occurred at the top of the Alat formation led to erosion and winnowing of the underlying fossil-bearing, fluvio-deltaic deposits. A large number of bones and artefacts were consequently accumulated at the base of channel fills, which represent a preferential horizon for fossil searching.     

Production of extracellular enzymes by Antarctic fungal strains

 Thirty-three fungal strains, isolated from different sites on Victoria Land (continental Antarctica), were plate-screened for their ability to produce twelve extracellular enzymes. Lipases were generally present and in high quantities in almost all the strains. Polygalacturonase, as well as amylase and phosphatase, was common. Glucose oxidase, protease and DNAase appeared to be generally low or absent. Many strains, producing a limited number of enzymes, appeared to have a low eco-nutritional versatility while a few, such as Verticillium cfr. lecanii no. 1, V. cfr. lecanii no. 3, Aspergillus versicolor and Phoma sp. no. 2, showing a diversified enzymatic competence, are probably advantaged in extreme terrestrial environments characterized by low competition. The possibility of utilizing the enzyme-producing ability of these fungi in applied research is also discussed. Received: 3 November 1995/Accepted: 29 May 1996     

Loss of p53 in mesenchymal stem cells promotes alteration of bone remodeling through negative regulation of osteoprotegerin

p53 plays a pivotal role in controlling the differentiation of mesenchymal stem cells (MSCs) by regulating genes involved in cell cycle and early steps of differentiation process. In the context of osteogenic differentiation of MSCs and bone homeostasis, the osteoprotegerin/receptor activator of NF-κB ligand/receptor activator of NF-κB (OPG/RANKL/RANK) axis is a critical signaling pathway. The absence or loss of function of p53 has been implicated in aberrant osteogenic differentiation of MSCs that results in higher bone formation versus erosion, leading to an unbalanced bone remodeling. Here, we show by microCT that mice with p53 deletion systemically or specifically in mesenchymal cells possess significantly higher bone density than their respective littermate controls. There is a negative correlation between p53 and OPG both in vivo by analysis of serum from p53^+/+, p53^+/−, and p53^−/− mice and in vitro by p53 knockdown and ChIP assay in MSCs. Notably, high expression of Opg or its combination with low level of p53 are prominent features in clinical cancer lesion of osteosarcoma and prostate cancer respectively, which correlate with poor survival. Intra-bone marrow injection of prostate cancer cells, together with androgen can suppress p53 expression and enhance local Opg expression, leading to an enhancement of bone density. Our results support the notion that MSCs, as osteoblast progenitor cells and one major component of bone microenvironment, represent a cellular source of OPG, whose amount is regulated by the p53 status. It also highlights a key role for the p53-OPG axis in regulating the cancer associated bone remodeling.Subject terms: Cell biology, Pathogenesis     

In utero substrate restriction by placental insufficiency or maternal undernutrition decreases optical redox ratio in foetal perirenal fat

Intrauterine growth restriction (IUGR) can result from reduced delivery of substrates, including oxygen and glucose, during pregnancy and may be caused by either placental insufficiency or maternal undernutrition. As a consequence of IUGR, there is altered programming of adipose tissue and this can be associated with metabolic diseases later in life. We have utilised two sheep models of IUGR, placental restriction and late gestation undernutrition, to determine the metabolic effects of growth restriction on foetal perirenal adipose tissue (PAT). Two-photon microscopy was employed to obtain an optical redox ratio, which gives an indication of cell metabolism. PAT of IUGR foetuses exhibited higher metabolic activity, altered lipid droplet morphology, upregulation of cytochrome c oxidase subunit genes and decreased expression of genes involved in growth and differentiation. Our results indicate that there are adaptations in PAT of IUGR foetuses that might be protective and ensure survival in response to an IUGR insult.