Recombinant mid gut antigen (Bm95) as a vaccine against Indian Rhiphicephalus haemaphysaloides in Bos indicus cattle

In the present study, we report for the first time the efficacy of recombinant Bm95 mid gut antigen isolated from an Argentinean strain of Rhipicephalus microplus strain A in controlling the tick infestations in India. The synthetic gene for Bm95 optimized for expression in yeast was obtained and used to generate yeast transformants expressing Bm95 which was purified to apparent homogeneity. Liquid chromatography-mass spectrometry analysis of the purified protein confirmed its identity as Bm95. Vaccine was prepared by blending various concentrations of purified Bm95 with aluminium hydroxide as an adjuvant. lmmunogenicity studies of the vaccine in rabbits and cattle indicated that the vaccine was highly immunogenic. The efficacy studies of the vaccine was done in cattle. Naive Bos indicus cattle were vaccinated with the recombinant vaccine and were challenged with the larval, nymphal and adult forms of Rhiphicephalus haemaphysaloides. The vaccine protected the animals from larval, nymph and adult tick challenges with an efficacy of 98.7%, 84.6% and 78.9% respectively. The results obtained from the above studies clearly demonstrated the advantage and possibilities of the use of Bm95 in controlling R. haemaphysaloides infestations in the field. (C) 2010 Elsevier Ltd. All rights reserved.

Antibodies raised against guanosine bind to double-stranded DNA

Antibodies elicited against guanosine have been reported to bind to single-stranded DNA. Using an avidin-biotin microELISA, we report that these antibodies also bind to double-stranded DNA. The binding is specific and is completely inhibited by the homologous hapten. The cross-reactivity of double-stranded DNA binding antibodies to single-stranded DNA is low. The antibodies are shown to bind to the topoisomers of plasmid DNA as assessed by a gel retardation assay.

Obliquely incident water waves against a vertical cliff

Utilizing the commutativity property of the Cartesian coordinate differential operators arising in the boundary conditions associated with the propagation of surface water waves against a vertical cliff, under the assumptions of linearized theory, the problem of obliquely incident surface waves is considered for solution. The case of normal incidence, handled by previous workers follow as a particular limiting case of the present problem, which exhibits a source/sink type behavior of the velocity potential at the shore-line. An independent method of attack is also presented to handle the case of normal incidence.

Protection of adult but not newborn mice against lethal intracerebral challenge with Japanese encephalitis virus by adoptively transferred virus-specific cytotoxic T lymphocytes: Requirement for L3T4(+) T cells

The protective ability of cytotoxic T cells (CTL) raised in vitro against Japanese encephalitis virus (JEV) was examined by adoptive transfer experiments. Adoptive transfer of anti-JEV effecters by intracerebral (i.c.) but not by intraperitoneal (i.p.) or intravenous (i.v.) routes protected adult BALB/c mice against lethal i.c. JEV challenge. In contrast to adult mice, adoptive transfer of anti-JEV effecters into newborn (4-day-old) and suckling (8-14-day-old) mice did not confer protection. However, virus-induced death was delayed in suckling mice compared to newborn mice upon adoptive transfer. The specific reasons for lack of protection in newborn mice are not clear but virus load was found to be higher in newborn mice brains compared to those of adults and virus clearance was observed only in adult mice brains but not in newborn mice brains upon adoptive transfer. Specific depletion of Lyt 2.2(+), L3T4(+) or Thy-1(+) T cell populations before adoptive transfer abrogated the protective ability of transferred effecters. However, when Lyt 2.2(+) cell-depleted and L3T4(+) cell-depleted effecters were mixed and transferred into adult mice the protective activity was retained, demonstrating that both Lyt 2.2(+) and L3T4(+) T cells are necessary to confer protection. Although the presence of L3T4(+) T cells in adoptively transferred effector populations enhanced virus-specific serum neutralizing antibodies, the presence of neutralizing antibodies alone without Lyt 2.2(+) cells was not sufficient to confer protection.

Effect of Speed and Pressure on Dry Sliding Interactions of Alumina against Steel

Sliding of alumina (87%) pins against a hardened steel disk over a range of pressures (3.3-30.0 MPa) and speeds (0.1-12.0 ms(-1)) has been studied. Four different regions (R1, R2, R3, and R4) of friction as a function of speed have been identified. R1 and RS exhibit single-valued friction while in R2 and R4 the friction exhibits dual behavior. The speed range over which these regions prevail is sensitive to the pressure. R1 and R2 are low-speed and low-temperature regions, and in both, metal transfer and formation and compaction of gamma-Fe2O3 occur. R3 and R4 are associated with high speeds and high interface temperatures. Formation of FeO, FeAl2O4, and FeAlO3 has been observed. The implications of the tribochemical interactions on friction and wear characteristics are discussed.

Sliding wear of YTZP ceramic against steel: observations on ceramic transfer and wear transition

Sliding tests were conducted, in air, of YTZP ceramic pins against steel discs at an applied pressure of 15.5 MPa over a speed range of 0.3 to 4.0 ms(-1). Pin wear was not detectable until 2.0 m s(-1), after which a finite but small wear rate was observed at 3.0 m s(-1), accompanied by a red glow at the contacting surface. A transition in wear behaviour and friction (mu) occurred at 4.0 ms(-1), increasing the former by over two orders of magnitude. Both mu and wear behaviour changed with time at 4.0 m s(-1). During initial periods mu was high and wear rate increased steadily with time accompanied by ceramic transfer onto the disc, which increased with time. When disc coverage exceeds a certain threshold value, mu decreased rapidly and the wear rate stabilized at a very high value. Metal transfer was not observed at any speed. High surface temperatures brought about significant adhesion between TZP and steel and this together with enhanced plastic deformation brought about a transition in wear behaviour.

Antioxidant and antihepatotoxic effect of Spirulina laxissima against carbon tetrachloride induced hepatotoxicity in rats

The vast biodiversity of nature provides bioactive compounds that may be useful in the fight against chronic diseases. This study was designed to investigate the protective effects of the ethanol extract of Spirulina laxissima West (Pseudanabaenaceae) (EESL) against carbon tetrachloride (CCl4) induced hepatotoxicities in rats. Male albino rats of Sprague-Dawley strain were treated orally with the ethanol extract of S. laxissima (50, 100 mg kg(-1) body wt.) 1 h before each CCl4 administration. The ethanol extract of S. laxissima showed the maximum antioxidant property in vitro. There were statistically significant losses in the activities of antioxidant enzymes and an increase in TBARS and liver function marker enzymes in the serum of the CCl4-treated group compared with the control group. However, all the tested groups were able to counteract these effects. The antioxidant activity of the extracts might be attributable to its proton-donating ability, as evidenced by DPPH. In the present study, the decline in the level of antioxidant observed in CCl4-treated rats is a clear manifestation of excessive formation of radicals and activation of the lipid peroxidation system resulting in tissue damage. The significant increases in the concentration of antioxidant enzymes in tissues of animals treated with CCl4 + EESL indicate the antioxidant effect of EESL. This study suggests that EESL can protect the liver against CCl4-induced oxidative damage in rats, and the hepatoprotective effect might be correlated with its antioxidant and radical-scavenging effects.

Mechanism of seizure of aluminium-silicon alloys dry sliding against steel

A steel ball was slid on aluminium-silicon alloys at different temperatures. After the coefficient of friction had been measured, the surface shear stress was deconvoluted using a two-term model of friction. The ratio of surface shear stress to bulk hardness was calculated as a function of temperature, silicon content and alloying additions. These results are qualitatively similar to those recorded for pre-seizure specimens slid against an En24 disc in a pin-on-disc machine. This similarity, when viewed in the context of the phenomenon of bulk shear, provides a model for seizure of these alloys.

On the incoming water waves against a vertical cliff

The problems of obliquely incident surface water waves against a vertical cliff have been handled in both the cases of water of infinite as well as finite depth by straightforward uses of appropriate Havelock-type expansion theorems. The logarithmic singularity along the shore-line has been incorporated in a direct manner, by suitably representing the Dirac's delta function.

Sliding wear of Al2O3-SiC-(Al,Si) composites against a steel counterface

The sliding-wear behavior of Al2O3-SiC-Al composites prepared by melt oxidation against a steel counterface has been recorded in a pin-on-disk machine. At high speeds and pressures (10 m/s, 20 MPa), friction and wear appear to be principally controlled by the in-situ formation of an interfacial film that consists of a layer of Fe3O4. The formation of this him is examined as a function of sliding speed, lubrication, and composite microstructure. A model is proposed in which high surface temperatures cause the preferential extrusion of aluminum from the composite onto the pin/disk interface. This promotes the adhesive pickup of iron and its oxidation to form a stable tribologically beneficial layer of Fe3O4.

Protection against UVB inactivation (in vitro) of rat lens enzymes by natural antioxidants

Oxidative damage, through increased production of free radicals, is believed to be involved in UV-induced cataractogenesis (eye lens opacification). The possibility of UVB radiation causing damage to important lenticular enzymes was assessed by irradiating 3 months old rat lenses (in RPMI-1640 medium) at 300 nm (100 mu Wcm(-2)) for 24 h, in the absence and presence of ascorbic acid, alpha-tocopherol acetate and beta-carotene. UVB irradiation resulted in decreased activities of hexokinase, glucose-6-phosphate dehydrogenase, aldose reductase, and Na, K- ATPase by 42, 40, 44 and 57% respectively. While endopeptidase activity (229%) and lipid peroxidation (156%) were increased, isocitrate dehydrogenase activity was not altered on irradiation. In the presence of externally added ascorbic acid, tocopherol and beta-carotene (separately) to the medium, the changes in enzyme activities (except endopeptidase) and increased lipid peroxidation, due to UVB exposure, were prevented. These results suggest that UVB radiation exerts oxidative damage on lens enzymes and antioxidants were protective against this damage.

Sliding wear of copper against alumina

OFHC copper pins with 10 ppm oxygen were slid against alumina at a load of 50 N and sliding speeds of 0.1 ms(-1) to 4.0 ms(-1) The wear characteristics of copper were related to the strain rate response of copper under uniaxial compression between strain rates of 0.1 s(-1) and 100 s(-1) and temperatures in the range of 298 K to 673 K. It is seen that copper undergoes flow banding at strain rates of 1 s(-1) up to a temperature of 523 K, which is the major instability in the region tested. These flow bands are regions of crack nucleation. The strain rates and temperatures existing in the subsurface of copper slid against alumina are estimated and superimposed on the strain rate response map of copper. The superposition shows that the subsurface of copper slid at low velocities is likely to exhibit flow band instability induced cracking. It is suggested that this is the,reason for the observed high wear rate at low velocities. The subsurface deformation with increasing velocity becomes more homogeneous. This reduces the wear rate. At velocities >2 ms(-1) there is homogenous flow and extrusion of thin (10 mu m) bands of material out of the trailing edge. This results in the gradual increase of wear rate with increasing velocity above 2.0 ms(-1).

GyrI: a counter-defensive strategy against proteinaceous inhibitors of DNA gyrase

DNA gyrase is the target of two plasmid-encoded toxins CcdB and microcin B17, which ensure plasmid maintenance. These proteins stabilize gyrase-DNA covalent complexes leading to double-strand breaks in the genome. In contrast, the physiological role of chromosomally encoded inhibitor of DNA gyrase (Gyrl) in Escherichia coli is unclear and its mechanism of inhibition has not been established. We demonstrate that the mode of inhibition of GyrI is distinct from all other gyrase inhibitors. It inhibits DNA gyrase prior to, or at the step of, binding of DNA by the enzyme. Gyrl reduces intrinsic as well as toxin-stabilized gyrase-DNA covalent complexes. Furthermore, Gyri reduces microcin B17-mediated double-strand breaks in vivo, imparting protection to the cells against the toxin, substantiating the in vitro results. Thus, Gyrl is an antidote to DNA gyrase-specific proteinaceous poisons encoded by plasmid addiction systems.

Lubricant Degradation and Related Wear of a Steel Pin in Lubricated Sliding Against a Steel Disc

In lubricated sliding contacts, components wear out and the lubricating oil ages with time. The present work explores the interactive influence between lubricant aging and component wear. The flat face of a steel pin is slid against a rotating steel disk under near isothermal conditions while the contact is immersed in a reservoir of lubricant (hexadecane). The chemical changes in the oil with time are measured by vibrational spectroscopy and gas chromatography. The corresponding chemistry of the pin surface is recorded using X-ray photoelectron spectroscopy while the morphology of the worn pins; surface and subsurface, are observed using a combination of focused ion beam milling and scanning electron 5 microscopy. When compared to thermal auto-oxidation of the lubricant alone, steel on steel friction and wear are found to accentuate the decomposition of oil and to reduce the beneficial impact of antioxidants. The catalytic action of nascent iron, an outcome of pin wear and disk wear, is shown to contribute to this detrimental effect. Over long periods of sliding, the decomposition products of lubricant aging on their own, as well as in conjunction with their products of reaction with iron, generate a thick tribofilm that is highly protective in terms of friction and wear.