Cloning and analysis of the gene for a major surface antigen of Mycoplasma gallisepticum

Myplasma gallisepticum infects a wide variety of gallineaceous birds including chickens, turkeys, and pheasants. Infection occurs both horizontally and vertically. Thus, control of the spread of M. gallisepticum to noninfected flocks is difficult. Continual monitoring is necessary to identify infected flocks even under the most stringent infectious control practices. Monitoring, however, is usually performed by measuring hemagglutination activity (HA) in serum, an insensitive and variable test. Variability in the HA test arises differences in agglutination antigen, changes in antigenic profiles of the M. gallisepticum strain, and variability in reading the agglutination reaction. Enzyme-linked immunosorbent assays (ELISAs) are the preferred method of testing because of the ease in obtaining sera and the sensitivity and reproducibility of the assays, but the ELISA suffers from a lack of standardization in the test antigen. The ELISA test will be more easily accepted once the test antigen has been standardized. To this end, we have identified, cloned, and characterized the gene for an antigen that has potential as a species-specific antigen for M. gallisepticum The gene codes for a 75-kD protein, P75, that is recognized during natural infections. Recombinant P75 is not recognized in immunoblots by convalescent sera produced in chickens infected with Mycoplasma synoviae, Mycoplasma gallinarum, and Mycoplasma gallinaceum or in turkeys infected with Mycoplasma meleagridis.     

Isolation and characterisation of Mycobacterium avium and Rhodococcus equi from granulomatous lesions of swine lymph nodes in Slovenia

Granulomatous lesions in bovine and especially swine lymph nodes are still frequently observed during routine veterinary meat inspections even though Mycobacterium bovis infections are no longer detected in domestic animals in Slovenia. Different lymph nodes of pigs (n = 260) were investigated using classical bacteriological and molecular methods. Mycobacterium avium alone was isolated in 47.3% of pigs and in mixed infection with Rhodococcus equi in 3.9% of pigs. R. equi alone was isolated in 27.3% and in mixed infection with mycobacteria other than M. avium in 1.5% of pigs. A total of 133 M. avium isolates were typed using the IS1245, IS901 and FR300 PCR. Almost two thirds (60.9%) of isolates belonged to M. avium hominissuis (IS901-, IS1245+ genotype), 33.8% of isolates belonged to M. avium avium (IS901+, IS1245+ genotype) and 5.3% of isolates remained non-typed. Fifty out of 85 R. equi isolates were tested for the virulence-associated antigens (VapA and VapB). Nearly two thirds (60.0%) were positive for VapB while all the other isolates were VapA- and VapB-negative.     

Enhancement of fungicidal and insecticidal activity by reductive alkylation of chitosan

A series of N-alkyl chitosan (NAC) derivatives were synthesized using a reductive alkylation reaction to examine their fungicidal and insecticidal activity. The chemical structures were characterized by IR and (1)H NMR spectroscopy, and the degree of substitution (DS) ranged from 0.02 to 0.37. Their fungicidal activity was evaluated against the grey mould Botrytis cinerea Pers ex Fr (Leotiales: Sclerotiniaceae) and the rice leaf blast pathogen Pyricularia grisea Sacc [Teleomorph: Magnaporthe grisea (Hebert) Barr] by a radial growth bioassay. It was of interest that most of the NAC derivatives were more active against both fungi than chitosan itself. The most active derivative was N-(2,2-diphenylethyl)chitosan with EC50 values of 0.031 and 0.23 g L(-1) against B. cinerea and P. grisea respectively. In addition, some derivatives, at higher concentrations up to 1.0 g L(-1), inhibited the mycelial growth and spore formation of P. grisea. Bioassays against larvae of the cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) with the NAC derivatives at a rate of 5.0 g kg(-1) in artificial diet demonstrated that N-(3-phenylbutyl)chitosan was the most active compound. In addition, N-propylchitosan, N-undecanylchitosan and N-(3-phenylpropyl)chitosan derivatives strongly inhibited larval weight gain in S. littoralis, with respective reductions of 76, 66 and 65% after 4 days of feeding on treated diet.     

Growth performance of sixty tree species in smallholder reforestation trials on Leyte, Philippines

Although many reforestation projects have attempted to mitigate deforestation in the Philippines, most have focused on planting introduced trees, often with low success rates. A smallholder-based project in the Visayas region planted native species instead. This study assessed the growth performance of forty-four native and sixteen introduced species in 25 sites established by this project between 1995 and 2000. Diameter at breast height and total height were measured for 2,789 trees. Mean annual increments for diameter (MAID) at breast height and height (MAIH) were significantly higher for trees planted on limestone-influenced soils (MAID = 1.19 cm/year; MAIH = 1.05 m/year) than on purely volcanic soils (MAID = 0.81 cm/year; MAIH = 0.78 m/year). Growth of two native species, Melia dubia and Terminalia microcarpa, was higher than that of the widely planted exotic Swietenia macrophylla. The height increment for the highest-performing dipterocarp species, Shorea guiso, Shorea contorta, and Parashorea malaanonan, was not statistically different from the MAIH of S. macrophylla. A range of soil characteristics predicted performance, with organic matter predicting growth for six species, and percent nitrogen and percent clay predicting performance of five species. These findings show that certain native species can perform better than some exotic species when planted in open areas. They also disprove the widely held belief in the Philippines that Dipterocarpaceae cannot be planted in grasslands, and suggest that dipterocarps can be used successfully in reforestation. Finally, the findings show that more research is needed on species-site matching and on silvicultural management of native species plantations.     

A Ni-Fe-Cu center in a bifunctional carbon monoxide dehydrogenase/acetyl-CoA synthase

A metallocofactor containing iron, sulfur, copper, and nickel has been discovered in the enzyme carbon monoxide dehydrogenase/acetyl-CoA (coenzyme A) synthase from Moorella thermoacetica (f. Clostridium thermoaceticum). Our structure at 2.2 angstrom resolution reveals that the cofactor responsible for the assembly of acetyl-CoA contains a [Fe4S4] cubane bridged to a copper-nickel binuclear site. The presence of these three metals together in one cluster was unanticipated and suggests a newly discovered role for copper in biology. The different active sites of this bifunctional enzyme complex are connected via a channel, 138 angstroms long, that provides a conduit for carbon monoxide generated at the C-cluster on one subunit to be incorporated into acetyl-CoA at the A-cluster on the other subunit.     

Crystal structure of the RC-LH1 core complex from Rhodopseudomonas palustris

The crystal structure at 4.8 angstrom resolution of the reaction center-light harvesting 1 (RC-LH1) core complex from Rhodopseudomonas palustris shows the reaction center surrounded by an oval LH1 complex that consists of 15 pairs of transmembrane helical alpha- and beta-apoproteins and their coordinated bacteriochlorophylls. Complete closure of the RC by the LH1 is prevented by a single transmembrane helix, out of register with the array of inner LH1 alpha-apoproteins. This break, located next to the binding site in the reaction center for the secondary electron acceptor ubiquinone (UQB), may provide a portal through which UQB can transfer electrons to cytochrome b/c1.     

Microbial reefs in the Black Sea fueled by anaerobic oxidation of methane

Massive microbial mats covering up to 4-meter-high carbonate buildups prosper at methane seeps in anoxic waters of the northwestern Black Sea shelf. Strong 13C depletions indicate an incorporation of methane carbon into carbonates, bulk biomass, and specific lipids. The mats mainly consist of densely aggregated archaea (phylogenetic ANME-1 cluster) and sulfate-reducing bacteria (Desulfosarcina/Desulfococcus group). If incubated in vitro, these mats perform anaerobic oxidation of methane coupled to sulfate reduction. Obviously, anaerobic microbial consortia can generate both carbonate precipitation and substantial biomass accumulation, which has implications for our understanding of carbon cycling during earlier periods of Earth's history.     

Molecular genetic and chemical assessment of Rhizoma Curcumae in China

Rhizoma Curcumae (Ezhu) is a traditional Chinese medicine that has been used in removing blood stasis and alleviating pain for over a thousand years. Three species of Curcuma rhizomes are being used, which include Curcuma wenyujin, Curcuma phaeocaulis, and Curcuma kwangsiensis. In China, the production of Rhizoma Curcumae largely depends on agricultural farming. The essential oils are considered as active constituents in Rhizoma Curcumae, which include curdione, curcumol, and germacrone. On the basis of the yield of curdione, curcumol, and germacrone in an orthogonal array design, the optimized extraction condition was developed. The amounts of these compounds within essential oils in Rhizoma Curcumae varied according to different species and their regions of cultivation. Chemical fingerprints were generated from different species of Curcuma, which therefore could serve as identification markers. In molecular genetic identification of Rhizoma Curcumae, the 5S-rRNA spacer domains of 5 Curcuma species, including the common adulterants of this herb, were amplified, and their nucleotide sequences were determined. Diversity in DNA sequences among various species was found in their 5S-rRNA spacer domains. Thus, the chemical fingerprint together with the genetic distinction could serve as markers for quality control of Curcuma species.     

Identification and stereochemical characterization of lignans in flaxseed and pumpkin seeds

Phytoestrogens of the lignan type are widely distributed in plant-derived food items and are believed to protect against hormone-dependent cancer. The richest known dietary source of lignans is flaxseed. Flaxseed has been reported to contain glycosides of secoisolariciresinol as the major lignan, together with small amounts of matairesinol, isolariciresinol, and pinoresinol. Secoisolariciresinol, but none of the other lignans, has so far been identified in pumpkin seeds. In the present study, two different methods for the hydrolysis of lignan glycosides are compared. Artifact formation and loss of lignans under acidic conditions were observed. Lariciresinol was identified by GC-MS analysis in two different types of flaxseed (Linum usitatissimum L. and Linum flavum L.) and in pumpkin seeds (Cucurbita pepo L.) for the first time. Likewise, the novel lignan demethoxy-secoisolariciresinol was tentatively identified in the flaxseed samples. Stereochemical analysis by chiral HPLC of several lignans isolated from flaxseed showed that secoisolariciresinol, matairesinol, and lariciresinol consisted predominantly of one enantiomer.