Ixodes heathi n. sp. (Acari: Ixodidae), a co-endangered tick from the critically endangered mountain pygmy possum (Burramys parvus), with notes on its biology and conservation

A new species of co-endangered tick, Ixodes heathi n. sp., is described from specimens of the nymph collected on the critically endangered mountain pygmy possum (Burramys parvus Broom) from the alpine region of Victoria, Australia. Its biology is discussed along with strategies for its conservation.

Green tea, red wine and lemon extracts reduce experimental tumor growth and cancer drug toxicity

AIM

To evaluate antitumor effect of plant polyphenol extracts from green tea, red wine lees and/or lemon peel alone and in combination with antitumor drugs on the growth of different transplanted tumors in experimental animals.

MATERIALS AND METHODS

Green tea extract (GTE) was prepared from green tea infusion. GTE-based composites of red wine (GTRW), lemon peel (GTRWL) and/or NanoGTE as well as corresponding nanocomposites were prepared. The total polyphenolics of the different GTE-based extracts ranged from 18.0% to 21.3%. The effects of GTE-based extracts were studied in sarcoma 180, Ehrlich carcinoma, B16 melanoma, Ca755 mammary carcinoma, P388 leukemia, L1210 leukemia, and Guerin carcinoma (original, cisplatin-resistant and doxorubicin-resistant variants). The extracts were administered as 0.1% solution in drinking water (0.6-1.0 mg by total polyphenolics per mouse per day and 4.0-6.3 mg per rat per day).

RESULTS

Tumor growth inhibition (TGI) in mice treated with NanoGTE, cisplatin or cisplatin + NanoGTE was 27%, 55% and 78%, respectively, in Sarcoma 180%, 21%, 45% and 59%, respectively, in Ehrlich carcinoma; and 8%, 13% and 38%, respectively in B16 melanoma. Composites of NanoGTE, red wine, and lemon peel (NanoGTRWL) enhanced the antitumor effects of cyclophosphamide in mice with Ca755 mammary carcinoma. The treatment with combination of NanoGTE and inhibitors of polyamines (PA) synthesis (DFMO + MGBG) resulted in significant TGI of P388 leukemia (up to 71%) and L1210 leukemia. In rats transplanted with Guerin carcinoma (parental strain), treatment with GTRW or GTE alone resulted in 25-28% TGI vs. 55-68% TGI in cisplatin-treated animals. The inhibition observed in the case of combination of GTE or GTRW with cisplatin was additive giving 81-88% TGI. Similar effects were observed when combinations of the cytostatics with GTE (or NanoGTE) were tested against cisplatin- or doxorubicin-resistant Guerin carcinoma. Moreover, the plant extracts lowered side toxicity of the drugs. Treatment with GTE, NanoGTE, and NanoGTRW decreased the levels of malondialdehyde in heart, kidney and liver tissue of experimental animals, as well as the levels of urea and creatinine in blood serum, increased erythrocyte and platelet counts, hemoglobin content, and decreased leucocyte counts.

CONCLUSION

The obtained data indicate the prospects for further development of GTE and corresponding nanocomposites as auxiliary agents in cancer chemotherapy.

Curcumin protects retinal cells from light-and oxidant stress-induced cell death

Age-related macular degeneration (AMD) is a complex disease that has potential involvement of inflammatory and oxidative stress-related pathways in its pathogenesis. In search of effective therapeutic agents, we tested curcumin, a naturally occurring compound with known anti-inflammatory and antioxidative properties, in a rat model of light-induced retinal degeneration (LIRD) and in retina-derived cell lines. We hypothesized that any compound effective against LIRD, which involves significant oxidative stress and inflammation, would be a candidate for further characterization for its potential application in AMD. We observed significant retinal neuroprotection in rats fed diets supplemented with curcumin (0.2% in diet) for 2 weeks. The mechanism of retinal protection from LIRD by curcumin involves inhibition of NF-kappaB activation and down-regulation of cellular inflammatory genes. When tested on retina-derived cell lines (661W and ARPE-19), pretreatment of curcumin protected these cells from H(2)O(2)-induced cell death by up-regulating cellular protective enzymes, such as HO-1, thioredoxin. Since, curcumin with its pleiotropic activities can modulate the expression and activation of many cellular regulatory proteins such as NF-kappaB, AKT, NRF2, and growth factors, which in turn inhibit cellular inflammatory responses and protect cells; we speculate that curcumin would be an effective nutraceutical compound for preventive and augmentative therapy of AMD.

Clarification of juice by thermolabile valencia pectinmethylesterase is accelerated by cations

Pectinmethylesterase (PME) was isolated from Valencia orange pulp and added to reconstituted juice at 1.2 units/mL of juice in the presence or absence of cations at 4.2 or 16.7 mM. The percent transmittance (%T) of control juices with no added PME or cation did not clarify. The %T of juices with added PME and added cation was 45-55% by the second day. Increases in the average particle size was observed with PME- or cation-added juices and preceded increases in %T. Most likely, cations displaced PME from an inactive pectin substrate complex and increased clarification. PME, in the absence of cations, increased particle size but did not affect %T, suggesting a direct interaction of PME with cloud particles.

Particle size distribution of orange juice cloud after addition of sensitized pectin

The effect of the addition of commercial pectin to orange juice that was de-esterified by alkaline treatment or pectinmethylesterase was evaluated. Pectin at various degrees of esterification (DE) was added to reconstituted frozen orange juice concentrate, and the extent of cloud loss was determined after centrifugation. Of the five pectin treatments, percent transmittance (% T) of juice remained <5%, except for the pectin treatment with a residual methoxyl content (% DE) of <5%. Addition of 100--600 ppm of 5% DE pectin to juice resulted in % T between 36 and 73%. Despite the absence of clarification, increases in cloud particle size were observed and depended on the % DE, the amount of pectin added, and the method used to modify the pectins.

Separation of thermostable pectinmethylesterase from marsh grapefruit pulp

A rapid, ion-exchange method that isolates thermostable pectinmethylesterase (TS-PME) from Marsh grapefruit pulp is presented. TS-PME was selectively extracted with 1 M NaCl and equilibrated at low pH (3.1 +/- 0.04). After dilution to a final concentration of 50 mM acetate buffer, pH 5.5, and 0.1, 0.25, or 0.5 M NaCl, the extract was applied to an ion-exchange column without ammonium sulfate precipitation and dialysis. The percent yield varied from an average of 70% (0.1 M NaCl) to 14% (0.5 M NaCl), with a specific activity of >400 U/mg protein in the latter sample. TS-PME activity of some column fractions varied compared with crude extracts before column separation. Some fractions lost thermostability after separation if loaded at 0.1 M or 0.25 M NaCl. In extracts that were loaded at 0.5 M NaCl, the TS-PME activity was significantly higher than that observed in the heated crude extracts. Ion-exchange chromatography may have separated an unidentified protective factor in PME fractions.

Role of cations in the catalysis of thermostable pectinmethylesterase extracted from Marsh grapefruit pulp

The de-esterification of high methoxyl pectin by thermostable pectinmethylesterase (TS-PME) from Marsh grapefruit was studied at pH 7.5, in a temperature range between 25 degrees and 50 degrees C and in the presence of various cations. Arrhenius plots were constructed for CaCl(2) (5 to 20 mM), SrCl(2) (5 to 20 mM), and spermidine (2.5 to 10 mM) added reactions. Enthalpy (DeltaH()) and entropy (DeltaS()) of activation changed with cation type and concentration. The presence of cations modified the free energy of the resulting enzyme/substrate complex. The entropy of activation was positive at all concentrations of CaCl(2) studied, and negative in the same concentration range with SrCl(2). Reactions with spermidine showed negative entropy of activation at concentrations <5 mM and positive values of entropy at higher concentrations.

Aqueous apple flavoring in breast muscle has physical, chemical, and sensory properties similar to those of phosphate-marinated controls

Marinades containing 0, 0.4, 0.8, and 1.2% apple flavoring were examined to determine the effect of an aqueous apple flavoring on the quality and sensory characteristics of boneless, skinless chicken breast. Marinade pickup and purge loss increased significantly with an increase of apple flavoring in marinades. Incorporation of apple flavoring in the marinades did not affect cook loss of the treatments, except for breast marinated in 1.2% apple flavor, which had higher cook loss. Apple flavoring did not affect final product yield of marinated breast. Shear values were similar for all treatments except marinades with 0.8% apple flavoring, which had lower shear values. Participants detected increases in fruity flavor with an increase of apple flavoring in the marinade. Products containing no apple flavoring were rated as "like moderately" to "like slightly." Products with 0.4% apple flavoring were rated "like slightly," and degree of liking declined to "neither like nor dislike" as apple flavoring increased. Incorporation of acceptable levels of apple flavoring is limited to 0.4%.

Kinetic compensation and the role of cations in pectinesterase catalysis

The catalytic rate constant of thermostable pectinesterase (TS-PE) from Marsh grapefruit pulp was determined at pH 7 at temperatures between 25 and 60 degrees C. TS-PE activity was measured at NaCl concentrations of 0.05, 0.10, 0.15, and 0.20 M and at CaCl(2) concentrations of 0.005, 0.010, 0.015, and 0.020 M. For sodium- and calcium-added conditions, the kinetic functions of this reaction agreed with kinetic compensation relations. The isokinetic temperatures for sodium- and calcium-added conditions were 327.8 and 312.4 K, respectively. Different isokinetic temperatures and compensation parameters suggest that sodium and calcium uniquely affect TS-PE catalysis. This is the first demonstration of kinetic compensation in an enzyme-catalyzed reaction.

Genetic control of giant perivascular space formation in the thymus of NOD mice

The immune system of NOD mice exhibits several anomalies, one being the intrathymic formation of giant perivascular spaces (PVSs) filled with mature thymocytes and some B-cells, intermingled within a network of extracellular matrix. The abnormal retention of thymocytes on their way to the periphery could have a profound impact on the nature of the exported cells and the regulation of autoimmune events. In the present study, we evaluated the appearance of this defect into F1 hybrids, the association with some of the known diabetes susceptibility loci (Idd genes) in a panel of NOD and reciprocal C57BL congenic strains, and the relative contribution of epithelial versus hematopoietic stroma. The analysis of F1 hybrid thymuses reveals a dominant expression of thymic giant PVS that is only marginally influenced by the outcross strain. Moreover, giant PVS expression in major histocompatibility complex (MHC) and Idd congenic mice is determined by the genetic background. All of the NOD congenics express the anomaly, irrespective of the Idd resistance alleles that have been introgressed, whereas none of the C57BL congenic mice present abnormal PVS. Finally, the expression of giant PVS in parental --> F1 bone marrow chimeras is predominantly controlled by the thymic NOD-derived hematopoietic microenvironment. In conclusion, the giant PVS formation in the NOD mouse thymus is a dominantly inherited anomaly associated with hematopoietic-derived tissue and with non-MHC genes. The exact contribution of PVS to the autoimmune process remains to be definitively established.

The role of CD4+ helper T cells in the destruction of microencapsulated islet xenografts in nod mice

Islet transplants for large numbers of patients with diabetes will require xenografts. Microencapsulation is an appealing method for islet xenografting. However, graft function has been limited by a cellular reaction, particularly intense in spontaneously diabetic, NOD mice. The purpose of this study was to elucidate the mechanism of this reaction. Poly-1-lysine-alginate microcapsules containing 4000-12,000 dog or 1800-2000 rat islets were xenografted intraperitoneally into streptozotocin (SZN)-diabetic C57BL/6J and NOD mice, with or without recipient treatment with GK 1.5 (anti-CD4 monoclonal antibody) (20-30 microliters i.p. every 5 days, begun on day -7. Grafts were considered technically successful if random blood glucose (BG) was normalized (less than 150 mg/dl) within 36 hr. Graft failure was defined as BG greater than 250 mg/dl. Dog and rat islets in microcapsules normalized BG in both SZN and NOD mice within 24 hr routinely. Empty microcapsules and GK 1.5 treatments alone did not affect BG. NODs destroyed both microencapsulated dog and rat islets more rapidly than did SZN-diabetic mice (P less than .01). Graft biopsies showed an intense cellular reaction, composed of lymphocytes, macrophages and giant cells, and no viable islets. GK 1.5 treatment significantly prolonged both dog-to-NOD and rat-to-NOD grafts (P less than 0.01). Biopsies of long-term functioning grafts (on days 65-85) demonstrated viable islets and no cellular reaction around microcapsules; 1/4 rat and 1/8 dog islet xenografts continued to function indefinitely in NOD recipients, even after cessation of GK 1.5 therapy. Prediabetic NODs receiving encapsulated dog or rat islets mounted a moderate cellular reaction to grafts. Empty microcapsules excited no cellular reaction in diabetic or prediabetic NODs. We conclude that the NOD reaction to microencapsulated xenogeneic islets is helper T cell-dependent, and that the target of this reaction is not the microcapsule itself, but the donor cells within.

The binding of 8-anilino-1-naphthalene sulfonate (ANS) to fish myosin and the effect of salts on the thermal transitions of fish myosin-ANS complex

Myosin prepared from tilapia (Serotherodon aureus) was complexed with 8-anilino-1-naphthalene sulfonate (ANS) and continuously heated at 1 degree C/min. A large increase in fluorescence was observed with a transition temperature of 34 degrees C. The effect of several salts on the transition temperature was tested. A plot based on the equation of E. E. Schrier and E. B. Schrier [(1967) J. Phys. Chem. 71, 1851-1860] gave a value of less than or equal to 500 cal/mol-deg for the change in enthalpy per residue due to exposure to solvent. The ratio of hydrophobic group to amide group exposure to solvent was intermediate compared with the ratio of RNase and gelatin. Fluorescence titrations yielded one high affinity site with a Kb of 2 X 10(6) M-1 and at least 200 low affinity sites with an average value of 1 X 10(5) M-1. The parameters did not change significantly with temperature. We propose that the increase in ANS fluorescence reflects changes in conformation of myosin as monitored by these low affinity sites, resulting in an increase in surface hydrophobicity and representing a small enthalpic change in the conformation of the myosin molecule. As a consequence, the change in conformation accelerates polymerization of myosin oligomers.

Immunological focusing by th mouse major histocompatibility complex: mouse strains confronted with distantly related lysozymes confine their attention to very few epitopes

The gallinaceous lysozymes are a family of antigens that are distantly related to mouse lysozyme. A T cell-dependent proliferation assay was used to characterize the spectrum of reactivities to lysozyme determinants in B10-congenic mice. Cross-reactivity studies using a panel of species variant lysozymes to stimulate lymph node cells from chicken egg white lysozyme- and ring-necked pheasant egg white lysozyme-primed B10.D2 mice indicated a preferential focusing of T cell reactivity onto a single determinant containing amino acids 113-114. These data, in conjunction with results obtained by priming with cyanogen bromide cleavage fragments of lysozymes, suggested that a site commmon to the L3 region (amino acids 106-129) of all the lysozymes tested was a preferential anchorage site for I region-encoded Ia molecules on H-2d antigen-presenting cells, leading to the limited display of a determinant containing residues 113-114. Priming with L2H (amino acids 13-105), a peptide containing the major epitopes recognized by B10. A and B10 mice, failed to stimulate any T cell proliferation by B10.D2 lymph node cells. Thus, it appears the Ia molecules in any one mouse strain attach to very few sites on lysozyme to effectively display antigenic determinants for T cell activation. This result points to a model of limited determinant selection even on a very "foreign" antigen based upon a shortage of appropriate amino acid residues usable by Ia antigen-presenting structures of a strain.