Biological coagulation of skim latex using Acinetobacter sp. isolated from natural rubber latex centrifugation effluent

An Acinetobacter sp, isolated from latex centrifugation effluent, effectively coagulated skim rubber from skim latex. After coagulation for 48 h without the addition of any nutrients, at an optimum dilution of 1:10(v/v) and with an inoculum concentration of 6.4 mg dry cell /ml, the yield of the skim rubber was 8 % (w/v) and the COD of the residual solution was only 0.4 g/l. chemical coagulation at the same dilution resulted in 7 % (w/v) yield of dry rubber content and 2.2 g COD /l.     

Functionalized, probe-containing, latex nanospheres.

Synthesis of surface-functionalized, probe-containing latex nanospheres is described. Approximately 40,000 probe ions may be encapsulated in a nanosphere of 50 nm diameter. The probe may be a radionuclide or a lanthanide with long-lived fluorescence. Alternatively, a "cargo" of pharmaceutical interest may be used. The surface of each nanosphere contains thousands of acid groups which may be functionalized for subsequent attachment to biomolecules such as antibodies. Functionalized nanospheres have been successfully coupled to a tobacco virus.     

Xanthones from Garcinia cowa Roxb. latex

Five xanthones named cowagarcinone A-E and six previously reported xanthones were isolated from the latex of Garcinia cowa Roxb. Their structures were determined on the basis of spectroscopic analysis. The crude latex and the isolated compounds were investigated for their radical scavenging activities.     

Measurement of latex proteins and assessment of latex protein exposure

Reduction of protein levels in manufactured natural rubber latex products is important for preventing sensitization and adverse allergic reactions to latex. Because of the complex nature of latex extracts, accurate protein measurement is a challenge. Standard total protein assays were effective in reducing protein levels from what were once extremely high levels, but these assays are plagued with false-positive reactions and limited sensitivity. An ELISA for antigenic protein has been standardized and promises to provide more consistent measurement of the proteins with potential to cause adverse reactions. Antigenic proteins represent the total protein fraction with potential to be allergenic. Measuring antigenic protein in a consistent manner should help to further reduce the level of sensitizing protein and further reduce allergic reactions to latex-medical products.     

A new method for fabrication of latex cuffs.

A new and simple method is presented that is suitable for the fabrication of inflatable cuffs for any gross vascular size. The method lends itself to mass production which is particularly useful for the fabrication of small cuffs. The procedure generally consists of spraying latex on a rotating cylinder in two separable layers. An activating tube is inserted between the layers and the edges sealed. Outward expansion is prevented by means of a suitable backing material.     

Rapid latex agglutination test for detection of staphylococcal enterotoxins A to E that uses high-density latex particles.

A rapid reversed passive latex agglutination method that uses high-density latex particles for the detection of staphylococcal enterotoxins (SE) A to E was developed. It took 3 h for incubation, much less than the 16 h needed with a customary latex agglutination test for SE detection such as a commercial test kit (SET-RPLA; Denka Seiken Co. Ltd., Tokyo, Japan). The rapid test was shown to be highly specific and sensitive for SE detection (detection limit, about 0.5 ng of SE per ml), comparable to the SET-RPLA test. The rapid test was also efficient in SE detection in foods and culture supernatants of staphylococcal strains, similar to the SET-RPLA test. This showed that a rapid test with high-density latex particles is fully reliable for use.     

Urethral response to latex and Silastic catheters.

The reaction of the urethral mucosa to latex and Silastic catheters was compared in two groups of patients undergoing prostatectomy. The bacteriologic response in the two groups differed little; however, Silastic catheters produced less cellular reaction than latex catheters.     

Quantitation of latex allergens

Minimizing allergen concentration in latex goods to prevent sensitization to natural rubber latex (NRL) and thereby the development of clinical allergy is acknowledged as of mutual interest for rubber manufacturers and regulatory health authorities. However, measuring total protein, the principal currently available method, cannot be deemed a satisfactory regulatory measure to control allergen content. Specific methods based on human IgE-containing reagents, such as radioallergosorbent test (RAST) inhibition, have been available in certain laboratories for demonstrating NRL allergens in rubber products but the methods lack standardization. Currently, one commercial test has become available for measuring individual NRL allergens by capture ELISA-based assays using monoclonal antibodies and purified or recombinant allergens. Such methods are specific, they can be properly standardized, and they are of sufficient sensitivity and reproducibility. Results from medical gloves collected in two national market surveys in Finland in 1995 and 1999, respectively, show that Hev b 6.02 and Hev b 5, the two major allergens for NRL-allergic adults, are the most abundant allergens regularly detectable in high- and moderate-allergen gloves. In addition, Hev b 3 and Hev b 1, the two major allergens for children with spina bifida, are also commonly found. In general, when the sum of the four allergens exceeded 1 microg/g, most NRL-allergic patients showed positive skin prick test reactions against them. Using these new methods assessment of threshold levels that could in due course become guidelines for the rubber industry and regulatory health authorities is becoming possible. Eventually, this progress is expected to lead to a declining incidence of latex allergy.     

Rapid hybridization kinetics of DNA attached to submicron latex particles.

We describe a novel method for attaching any DNA molecule to submicron latex beads and characterize the hybridization kinetic properties of these bead-DNA conjugates. The conjugates hybridize to DNA in solution with rates comparable to homogeneous hybridization reactions, are compatible with common hybridization conditions and are conveniently manipulated. They should thus serve as useful reagents for the fractionation and characterization of DNA and RNA.     

Enzymatic activities and protein profile of latex from Calotropis procera.

The laticifer fluid of Calotropis procera is rich in proteins and there is evidence that they are involved in the pharmacological properties of the latex. However, not much is known about how the latex-containing proteins are produced or their functions. In this study, laticifer proteins of C. procera were pooled and examined by 1D and 2D electrophoresis, masses spectrometry (MALDI-TOF) and characterized in respect of proteolytic activity and oxidative enzymes. Soluble laticifer proteins were predominantly composed of basic proteins (PI>6.0) with molecular masses varying between 5 and 95 kDa. Proteins with a molecular mass of approximately 26,000 Da were more evident. Strong anti-oxidative activity of superoxide dismutase (EC 1.15.1.1) (1007.74+/-91.89 Ug(-1)DM) and, to a lesser extent ascorbate peroxidase (EC 1.11.1.1) (0.117(d)+/-0.013 microMol H(2)O(2)g(-1)min(-1)), were detected. However, catalase (EC 1.11.1.6) was absent. The strong proteolytic activities of laticifer proteins from C. procera were shown to be shared by at least four distinct cysteine proteinases (EC 3.4.22.16) that were isolated by gel filtration chromatography. Serine and metaloproteinases were not detected and aspartic proteinase activities were barely visible. Chitinases (EC 3.2.1.14) were also isolated in a chitin column and their activities quantified. The presence of these enzymatic activities in latex from C. procera may confirm their involvement in resistance to phytopathogens and insects, mainly in its leaves where the latex circulates abundantly.