Cryptosporidium and wildlife: a risk for humans?

The present review underlines the knowledge of Cryptosporidium, especially its biodiversity and transmission. The presence of the parasite in different mammal host species is discussed with real, potential risk of transmission to humans. The potential role of insects in mechanical transmission of the parasite is evaluated by experimental protocols. The cost of cryptosporidiosis at health and economic levels are mentioned, which emphasises the importance of detection and identification of the parasite in the environment and in wild mammal species, using specific molecular tools. Potential measures to be accomplished in order to fight off cryptosporidiosis are also noted.     

Zn- and Cu-thioneins: a functional classification for metallothioneins?

This report intends to provide the reader with a deeper insight in the chemical, and extensively biological, characteristics of the metallothionein (MT) system. We have devoted nearly 20 years to the study of MTs and this has allowed us to form what we believe is a more complete picture of this peculiar family of metalloproteins. At the beginning of the 1990s, the landscape of this field was quite different from the overall picture we have now. Many researchers have contributed to the readjustment of this part of scientific knowledge. In our case, we implemented a unified method for obtaining MTs, for characterizing their metal-binding features, and for applying a unified research rationale. All this has helped to enlarge the initial picture that was mainly dominated by mammalian MT1/MT2 and yeast Cup1, by introducing approximately 20 new MTs. It has also allowed some characteristics to be clarified and examined in more detail, such as the cooperativity or the coexistence of multiple species in the metal-substitution reactions, the availability of Ag(I) or Cd(II) for use as respective probes for the Cu(I) and Zn(II) binding sites, the participation of chloride or sulfide ligands in the metal coordination spheres, and the feasibility of using in vitro data as representative of in vivo scenarios. Overall, the results yield enough data to consider new criteria for a proposal of classification of MTs based on MT metal-binding features, which complements the previous classifications, and that can shed light on the still controversial physiological functions of this peculiar superfamily of metalloproteins.     

Plants and biotrophs: a pivotal role for cytokinins?

Plants infected with biotrophic fungal pathogens exhibit reduced photosynthetic rates, nutrient mobilization towards infection sites and, in interactions where discrete pustules are formed, green islands are induced. The ability of cytokinins to mobilize nutrients towards sites of application and to delay senescence led researchers to speculate that cytokinins might be involved in nutrient mobilization and green island formation in plants infected with biotrophic fungi. There is evidence that the reduction in photosynthesis in infected leaves results from early increases in invertase activity, leading to carbohydrate accumulation and the downregulation of photosynthetic metabolism. In this Opinion article, we propose that these seemingly disparate changes in host physiology in infected plants are the result of cytokinin-induced increases in invertase activity occurring early on in the host-pathogen interaction.     

Plants and animals: a different taste for microbes?

Plants and animals can recognize potential pathogens by detecting pathogen-associated molecular patterns (PAMPs). Significant advances over the past few years have begun to unveil the molecular basis of PAMP perception by pattern recognition receptors (PRRs). Although these discoveries highlight common recognition strategies among higher eukaryotes, they also show differences with respect to the nature of the receptors involved and the exact molecular patterns recognized. This suggests a convergent evolution of microbe sensing by the innate immune systems of these various organisms.     

Autophagy and vacuole homeostasis: a case for self-degradation?

The vacuole of yeast plays an important role in pH- and ion-homeostasis. Another important function of the vacuole, especially during nutrient deprivation, is the degradation of proteins, other macromolecules and organelles. To deliver these components into the vacuolar lumen, specific and sophisticated transport pathways such as autophagy have evolved. This review will first look at autophagy and its relationship to vacuole homeostasis, then move to the topic of vacuole self-degradation and possible reasons for its existence, and close by pointing very briefly to some areas for further research in these topics.     

PRIMARY CUTANEOUS COCCIDIOIDOMYCOSIS—The Criteria for Diagnosis and a Report of a Case

Study was made of a case of coccidioidomycosis known to have resulted from primary inoculation of the organisms into the skin. Clinical observations and laboratory data were obtained at the time of clinical illness and for a period of five years thereafter. From the information thus obtained and correlation of it with what already was known of coccidioidomycosis, it was concluded that the disease originates very rarely as the result of primary cutaneous inoculation. In most instances lesions suspected to be of this type have actually resulted by dissemination of the organisms to the skin from a previously unrecognized pulmonary focus.Primary cutaneous coccidioidomycotic lesions closely resemble the primary cutaneous lesions (chancres) in other infectious granulomata, such as syphilis, tuberculosis and sporotrichosis. Spontaneous involution should occur within three months and then there should be immunity to reinfection in all but one or two per thousand instances.From these observations certain criteria were evolved by which to determine in a case of coccidioidomycosis with cutaneous manifestations whether or not the infecting organism entered through the skin.     

Synthesis and characterization of a fluorescent probe for α-tocopherol suitable for fluorescence microscopy

Previously prepared fluorescent derivatives of α-tocopherol have shown tremendous utility in both in vitro exploration of the mechanism of ligand transfer by the α-tocopherol transfer protein (α-TTP) and the intracellular transport of α-tocopherol in cells and tissues. We report here the synthesis of a 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) containing α-tocopherol analog having extended conjugation with an alkenyl thiophene group that extends the absorption and emission maxima to longer wavelengths (λ_ex = 571 nm and λ_em = 583 nm). The final fluorophore thienyl-ene-BODIPY-α-tocopherol, 2, binds to recombinant human α-TTP with a K_d = 8.7 ± 1.1 nM and is a suitable probe for monitoring the secretion of α-tocopherol from cultured Mcf7#189 cells.     

Can a membrane oxygenator be a model for lung NO and CO transfer?

To model lung nitric oxide (NO) and carbon monoxide (CO) uptake, a membrane oxygenator circuit was primed with horse blood flowing at 2.5 l/min. Its gas channel was ventilated with 5 parts/million NO, 0.02% CO, and 22% O2 at 5 l/min. NO diffusing capacity (Dno) and CO diffusing capacity (Dco) were calculated from inlet and outlet gas concentrations and flow rates: Dno = 13.45 ml.min(-1).Torr(-1) (SD 5.84) and Dco = 1.22 ml.min(-1).Torr(-1) (SD 0.3). Dno and Dco increased (P = 0.002) with blood volume/surface area. 1/Dno (P < 0.001) and 1/Dco (P < 0.001) increased with 1/Hb. Dno (P = 0.01) and Dco (P = 0.004) fell with increasing gas flow. Dno but not Dco increased with hemolysis (P = 0.001), indicating Dno dependence on red cell diffusive resistance. The posthemolysis value for membrane diffusing capacity = 41 ml.min(-1).Torr(-1) is the true membrane diffusing capacity of the system. No change in Dno or Dco occurred with changing blood flow rate. 1/Dco increased (P = 0.009) with increasing Po2. Dno and Dco appear to be diffusion limited, and Dco reaction limited. In this apparatus, the red cell and plasma offer a significant barrier to NO but not CO diffusion. Applying the Roughton-Forster model yields similar specific transfer conductance of blood per milliliter for NO and CO to previous estimates. This approach allows alteration of membrane area/blood volume, blood flow, gas flow, oxygen tension, red cell integrity, and hematocrit (over a larger range than encountered clinically), while keeping other variables constant. Although structurally very different, it offers a functional model of lung NO and CO transfer.     

Synthesis and evaluation of a netropsin–proximicin-hybrid library for DNA binding and cytotoxicity

The proximicins A–C (1–3) are novel naturally occurring γ-peptides with a hitherto unknown 2,4-disubstituted furan amino acid as a core structure. They show a moderate cytotoxic activity and induce upregulation of cell cycle regulating proteins (p53 and p21) and lead to cell cycle arrest in G0/G1-phase. Hybrid molecules combining structural motifs of the proximicins and of netropsin (4), a structurally related natural product, seem to have similar effects. Herein we describe the synthesis of a netropsin–proximicin-hybrid library and its evaluation regarding cytotoxicity and minor groove binding activity.     

Ligation and mucopexy for prolapsing hemorrhoids – a ten year experience

Objective

The aim of this study is to clinically test the efficacy of author's approach of suture ligation and mucopexy for patients having symptomatic and prolapsing hemorrhoids.

Materials and methods

616 patients (255 females) complaining of symptoms of hemorrhoids were included in the study. The hemorrhoids were suture ligated with an absorbable suture material under vision. Operating time, postoperative complications, time to return to work, and outcome of the procedure were analyzed. Follow-up was planned following discharge after 1 month, 6 months and after at least 1 year. Patient satisfaction was also assessed.

Results

The mean procedure time was 8 ± 0 minutes (range, 6–15 minutes), and the total admission period was 12 ± 4 Hours. Perianal thrombosis and skin tags were the commonest post-operative complications. The mean total analgesic dose and duration of pain control using analgesics was 19 ± 4 tablets, and 9 ± 3 days respectively. The postoperative follow up after 4 weeks revealed therapeutic success in 589 patients (95.6%), who presented with hemorrhoidal bleeding. Prolapse was no longer observed in 98% of patients and 96% patients experienced no pain after defecation. 93% patients completed the one-year follow-up and 89 percent of them were asymptomatic. The patient satisfaction scoring was 8.2% on visual analogue scale.

Conclusion

Suture ligation and mucopexy of hemorrhoids is an easy-to-perform technique that is well accepted by patients and has good results for prolapsing hemorrhoids.     

Transglycosylation: a mechanism for RNA modification (and editing?)

The vast majority of the ca. 100 chemically distinct modified nucleosides in RNA appear to arise via the chemical transformation of a genetically encoded nucleoside. Two notable exceptions are queuosine and pseudouridine, which are incorporated into tRNA via transglycosylation. Transglycosylation is an extremely efficient process for incorporating highly modified bases such as queuine into RNA. Transglycosylation is also a requisite process for "isomerizing" an N-nucleoside into a C-nucleoside as is the case for pseudouridine formation. Finally, transglycosylation is an attractive possibility for certain RNA editing events (e.g., pyrimidine to purine conversions) that cannot occur via the known, more straightforward enzymatic reactions (e.g., deaminations). This review discusses what is known about the mechanisms of transglycosylation for the queuine and pseudouridine RNA modifications and will speculate about a potential role for transglycosylation in certain RNA editing events.     

Estrogen and mitochondria: a new paradigm for vascular protection?

Mitochondrial dysfunction has been implicated as a cause of age-related disorders, and the mitochondrial theory of aging links aging, exercise, and diet. Endothelial dysfunction is a key paradigm for vascular disease and aging, and there is considerable evidence that exercise and dietary restriction protect against cardiovascular disease. Recent studies demonstrate that estrogen receptors are present in mitochondria and that estrogen promotes mitochondrial efficiency and decreases oxidative stress in the cerebral vasculature. Chronic estrogen treatment increases mitochondrial capacity for oxidative phosphorylation while decreasing production of reactive oxygen species. The effectiveness of estrogen against age-related cardiovascular disorders, including stroke, may thus arise in part from hormonal effects on mitochondrial function. Estrogen-mediated mitochondrial efficiency may also be a contributing factor to the longer lifespan of women.     

Xenotransplantation: a tool for reproductive biology and animal conservation?

The transplantation of reproductive organs, including ovaries and ovarian tissue, was pioneered over 100 years ago. In the 1960s, ovarian grafting was used as a tool to investigate ovarian function, but with the recent development of more effective cryopreservation protocols for ovarian tissue, germline preservation and propagation have now become realistic goals. This review describes progress in ovarian banking and ovarian tissue transplantation, with emphasis on how fresh and frozen ovarian tissue can be used in assisted reproduction for both humans and animals. This paper focuses most closely on the potential value of xenotransplantation, the transplantation of gonads from one species to another, to conserve rare and endangered species. Specific attention is drawn to the use of xenotransplantation as a strategy for generating viable gametes that can be used to produce live fertile offspring. Other upcoming xenogeneic technologies that may be of potential significance in animal conservation, such as transplantation of whole ovaries or isolated growing follicles, and even male germ cells, are discussed.     

Mitochondria and aging: a role for the permeability transition?

When mitochondria are subjected to oxidative stress and relatively high [Ca2+], they undergo a "permeability transition" in which the inner membrane becomes freely permeable to low-molecular-weight solutes. This phenomenon reflects reversible deformation of the adenine nucleotide translocase, the loss of its native gating properties and the stabilization of the deformed state by cyclophilin-D. The permeability transition may be a factor in cell dysfunction associated with aging. This can manifest in a number of ways ranging, in the most severe, from impaired energy transduction and compromised viability to more subtle influences on the propagation of Ca2+ signals. This article critically examines data relevant to this issue.     

Skin aging: a role for telomerase and telomere dynamics?

Skin is a complex tissue composed of two very different compartments -- the continuously renewing epidermis made up mostly by keratinocytes and the underlying matrix-rich dermis with the resting fibroblasts as its major cellular components. Both compartments are tightly interconnected and a paracrine mutual interaction is essential for epidermal growth, differentiation, and tissue homeostasis. Skin aging is commonly viewed as wrinkle formation, hair greying, and impaired wound healing. Nevertheless, the epidermis as the outermost shield needs to remain intact in order to guarantee an inside-out and outside-in barrier function throughout life time of a human being. Furthermore, the epidermis is one of the few regenerative tissues that express telomerase, the ribonucleoprotein complex that can counteract telomere erosion, one of the presently mostly favoured potential mechanisms causing cellular aging. This raises the question whether in the epidermis telomerase is able to counteract telomere erosion and thereby to prevents a telomere-dependent aging process and consequently which part of the skin is responsible for the most obvious changes associated with skin aging.     

MolTalk – a programming library for protein structures and structure analysis

Background  

Two of the mostly unsolved but increasingly urgent problems for modern biologists are a) to quickly and easily analyse protein structures and b) to comprehensively mine the wealth of information, which is distributed along with the 3D co-ordinates by the Protein Data Bank (PDB). Tools which address this issue need to be highly flexible and powerful but at the same time must be freely available and easy to learn.     

Trypanosomiasis and trypanotolerance in cattle: a role for congopain?

A Trypanosoma congolense cysteine protease (congopain) elicits a high IgG response in trypanotolerant but not in trypanosusceptible cattle during primary infections. As discussed here by Edith Authié, this observation suggests that congopain, like other parasite cysteine proteases, may play a role in pathogenicity and that more efficient immune responses to congopain may contribute to trypanotolerance.