Susceptibility of Eucalyptus grandis and Acacia mearnsii seedlings to five Phytophthora species common in South African plantations

Eucalyptus grandis and its hybrids, as well as Acacia mearnsii, are important non‐native trees commonly propagated for forestry purposes in South Africa. In this study, we conducted pathogenicity trials to assess the relative importance of five commonly isolated Phytophthora spp. (Phytophthora alticola, P. cinnamomi, P. frigida, P. multivora and P. nicotianae) from the plantation environment on E. grandis and A. mearnsii seedlings. Overall E. grandis was more susceptible to the tested Phytophthora spp. than A. mearnsii. Phytophthora cinnamomi was the only pathogen that had a significant negative effect on both the host tree species, leading to a reduction in root and shoot weight as well as to death in the case of E. grandis. Phytophthora alticola and P. nicotianae exclusively affected E. grandis and A. mearnsii, respectively. This study updated the current knowledge on the pathogenicity of Phytophthora spp. on two important non‐native commercially propagated tree species from South Africa.     

Biocatalysis for the production of industrial products and functional foods from rice and other agricultural produce

Many industrial products and functional foods can be obtained from cheap and renewable raw agricultural materials. For example, starch can be converted to bioethanol as biofuel to reduce the current demand for petroleum or fossil fuel energy. On the other hand, starch can also be converted to useful functional ingredients, such as high fructose and high maltose syrups, wine, glucose, and trehalose. The conversion process involves fermentation by microorganisms and use of biocatalysts such as hydrolases of the amylase superfamily. Amylases catalyze the process of liquefaction and saccharification of starch. It is possible to perform complete hydrolysis of starch by using the fusion product of both linear and debranching thermostable enzymes. This will result in saving energy otherwise needed for cooling before the next enzyme can act on the substrate, if a sequential process is utilized. Recombinant enzyme technology, protein engineering, and enzyme immobilization are powerful tools available to enhance the activity of enzymes, lower the cost of enzyme through large scale production in a heterologous host, increase their thermostability, improve pH stability, enhance their productivity, and hence making it competitive with the chemical processes involved in starch hydrolysis and conversions. This review emphasizes the potential of using biocatalysis for the production of useful industrial products and functional foods from cheap agricultural produce and transgenic plants. Rice was selected as a typical example to illustrate many applications of biocatalysis in converting low-value agricultural produce to high-value commercial food and industrial products. The greatest advantages of using enzymes for food processing and for industrial production of biobased products are their environmental friendliness and consumer acceptance as being a natural process.     

Effect of exogenous FSH on ovulation rate in homozygous carriers or noncarriers of the Booroola FecB gene after hypothalamic-pituitary disconnection or after treatment with a GnRH agonist

We have tested the hypothesis "that the ovulation rate in homozygous carriers (BB) and noncarriers (+2) of the Booroola FecB gene would not be different if the plasma concentrations of follicle-stimulating hormone (FSH) in the two genotypes were similar." For this purpose we used two experimental animal models: 1) the hypothalamic-pituitary disconnected (HPD) ovary-intact ewe; and 2) and GnRH agonist (i.e., Deslorelin)-treated ewe. Following HPD or Deslorelin treatment, the animals had low plasma concentrations of gonadotropins and were anovulatory. In both animal models, BB and +2 ewes were treated with exogenous pregnant mares serum gonadotropin (PMSG) and varying doses of FSH to induce preovulatory follicular growth, and human chorionic gonadotropin (hCG) to induce ovulation. HPD or Deslorelin-treated animals administered with pregnant mares serum gonadotropin without FSH followed by human chorionic gonadotropin failed to ovulate. However for both animal models, the proportion of BB and +2 ewes ovulating to various doses of FSH differed such that significantly greater proportions of +2 animals ovulated relative to the BB genotype (P < 0.05). When HPD or Deslorelin-treated BB and +2 ewes were administered identical doses of FSH, the mean ovulation rate and plasma concentrations of FSH in those animals which ovulated was the same in both genotypes. These findings confirm, at least in part, the aforementioned hypothesis. The results also demonstrated that higher ovulation rates were obtained in both genotypes as the FSH dose was increased. Collectively, these findings infer that the higher mean ovulation rate in normal intact BB ewes compared to the +2 genotype is attributable to effects of the FecB gene at the level of ovarian follicular development as well as at the level of pituitary FSH release.     

Study of the short- and long-term outcomes of 65 horses with peritonitis

The records of 65 horses with peritonitis examined at two uk referral centres over a period of 12 years were reviewed. Peritonitis was defined in terms of the horse's peritoneal fluid containing more than 5 x 10(9) nucleated cells/l. Horses that had developed peritonitis after abdominal surgery or a rupture of the gastrointestinal tract were excluded. Of the 65 horses, 56 (86 per cent) survived to be discharged. Follow-up information was obtained from practice records and telephone calls to the owners for 38 of the horses. Of these, 32 (84 per cent) had survived for at least 12 months and were considered to be long-term survivors; the others six were euthanased within 12 months. Thirteen (34 per cent) of the horses discharged had experienced complications that could have been sequelae to peritonitis and eight of the 13 were euthanased. The cause of the peritonitis was identified in 15 cases; survival rates were lowest in horses with peritonitis secondary to urinary tract involvement or intra-abdominal masses. Of the other 50 cases, 47 (94 per cent) survived to discharge, but two were euthanased owing to recurrent colic.     

Prevalence of Rickettsia felis DNA in the blood of cats and their fleas in the United States

Rickettsia felis is associated with fever, headache, myalgia, and macular rash in some infected humans and has been detected in the cat flea (Ctenocephalides felis) in many countries around the world. While some naturally exposed cats have been assessed for antibodies against R felis, to our knowledge, no one has reported use of polymerase chain reaction (PCR) to attempt to amplify R felis DNA from client-owned cats and the fleas collected from them. In this study, we assayed 92 pairs of cat blood and flea extracts from Alabama, Maryland and Texas, using PCR assays that amplify a region of the citrate synthase gene (gltA) and the outer membrane protein B gene (ompB). Of the 92 pairs, 62 of 92 (67.4%) flea extracts and none of the cat blood samples were positive for R felis DNA.