A preliminary report on the use of FAMACHA for haemonchosis in goats in the Eastern Cape Province of South Africa during the late autumn/early winter period

From May to July 2005 a study was conducted on the prevalence and effects of haemonchosis in goats farmed on communal grazing belonging to resource-poor farmers at two study sites, namely Mlungisi (26 degrees 53'E, 31 degrees 53'S) and Ezibeleni (26 degrees 58'E, 31 degrees 53'S), situated within the Chris Hani District Municipality in Eastern Cape Province of South Africa. The usefulness of the FAMACHA system for identifying goats needing treatment was confirmed. It allowed stock owners to identify badly affected goats accurately, as borne out by the agreement between FAMACHA scores and corresponding haematocrits.     

Artificial Neural Network Modelling of Leaf Water Potential for Potatoes Using RGB Digital Images: A Greenhouse Study

Plant water status information of potato (Solanum tuberosum L. cv. Russet Burbank) is needed at the farm level for irrigation scheduling. This research investigated the feasibility of using a 5-megapixel digital camera to determine the leaf water potential (Ψ_L) of potato plants by capturing red, green, blue (RGB) digital images in the visible region of the electromagnetic spectrum. A greenhouse experiment was conducted in containerized cv. Russet Burbank potato plants subjected to five soil nitrate-nitrogen (N) levels and four soil water content levels. An artificial neural network (ANN) model, built with RGB images, RGB image transformations, RGB vegetation indices, and principal components analysis, found that for the validation data set, the measured Ψ_L and predicted Ψ_L results were from common populations. Other results showed: (1) a linear trend between soil nitrate-N levels and leaf reflectance in the G image band, (2) that the RG image bands were more suitable than the B image band for classifying leaf pigment from leaf shadow and leaf damage, (3) soil nitrate-N interacted with leaf greenness, affecting Ψ_L prediction, and (4) some image variables were more important than others in the ANN model. Although this greenhouse research shows promise, further field-based research is required to validate the selection of input neurons used and also validate the use of ANN modelling to determine Ψ_L at the plant canopy level with cv. Russet Burbank and other cultivars. In addition, an image acquisition method needs to be developed to obtain periodic representative sample coverage over a field.     

Sterol Ring System Oxidation Pattern in Marine Sponges

The marine sponges (Porifera) are a unique group of sedentary organisms from which several novel natural products are reported, many of which have useful biological activities. In producing unusual sterols, they occupy a preeminent position among the various groups of organisms. The polar sterols of sponges reported as at the end of the year 2002 number about 250; their ring structure changing a hundred times. The oxidation pattern in the sterol ring system, from the point of view of biogenesis seems to be mainly of four types. Each sponge species is able to produce sterols fitting into one of the four main biogenetic pathways viz., (i) 3β-hydroxy-Δ⁵-sterol pathway, (ii) 3β-hydroxy-Δ⁷-sterol pathway, (iii) 3β-hydroxy-Δ^5,7-sterol pathway, and (iv) 3α-hydroxy sterol pathway.     

Pathogenic and Genetic Diversity of Magneporthe oryzae Populations from Sri Lanka

The present study was undertaken to determine the pathogenic and the genetic diversity of the isolates of M.oryzae collected from the wet,intermediate and dry zones of Sri Lanka with a view to develop rice varieties conferring durable resistance to rice blast.No significant morphological or growth variations existed amongst the isolates studied.The genetic diversity of isolates determined by carrying out Pot2 transposable element based on repetitive-PCR revealed that the majority of isolates (92%) clustered into a single group with 45.4% similarity.The existence of nine pathotypes was identified by observing the reaction type of isolates on 16 different rice lines.Pathotype 1 which was distributed in all zones affected only one differential line.Pathotype 2 which was able to infect six lines was restricted only to the dry zone of Sri Lanka.Of the 16 rice lines,seven lines,K3 (Pik-h),C101A51 (Piz5),K1 (Pita),C105TTP2L9 (Pita),K59 (Pit),Shin (Pish) and WHD-1S-75-1-127 (Pi9) had highly effective blast resistance.None of the isolates of the fungus showed any virulence against the seven lines.These seven blast resistant lines can be used in the breeding programmes in Sri Lanka for development of lines conferring durable resistance to rice blast.     

Enzymatic saccharification and ethanol production of <Emphasis Type="Italic">Acacia mangium</Emphasis> and <Emphasis Type="Italic">Paraserianthes falcataria</Emphasis> wood,and <Emphasis Type="Italic">Elaeis guineensis</Emphasis> trunk

We examined the saccharification and fermentation of meals from Acacia mangium wood, Paraserianthes falcataria wood, and Elaeis guineensis trunk. The levels of enzymatic hydrolysis of cellulose and ethanol production were highest for P. falcataria wood and lowest for A. mangium wood. Ultrasonication pretreatment of meal further increased the rates of hydrolysis and ethanol production in meal from P. falcataria wood. Through this pretreatment, hemicelluloses (xylan and xyloglucan) and cellulose were released in the meal from P. falcataria wood. Loosening of hemicellulose associations can be expected to make P. falcataria wood more useful for bioethanol production.     

Effect of the lateral growth rate on wood properties in fast-growing hardwood species

We investigated the feasibility of using several fast-growing tropical or subtropical hardwood species for timber production by measuring key wood qualities in relationship to the high rates of lateral growth. The trees tested were sampled from even-aged plantations of Acacia mangium, A. auriculiformis, hybrid Acacia (A. mangium × A. auriculiformis), Eucalyptus grandis, E. globulus, and Paraserianthes falcataria (Solomon and Java origin) that had already reached commercial harvesting age. The released strain of the surface growth stress (RS), xylem density (XD), microfibril angle (MFA), and fiber length (FL) were measured at the outermost part of the xylem at breast height in each tree. Results were then compared to the lateral growth rate (radius/age) at breast height, which provides a relative indicator of the amount of tree growth per year. Our findings indicated that RS was constant, regardless of lateral growth rate in each species. Similar results were observed for XD, MFA, and FL, with a few exceptions, suggesting that high growth rates do not intrinsically affect the wood properties of fast-growing tropical or subtropical species that have reached harvesting age. However, special attention must be paid to patterns of xylem maturation when developing plantations of such species.     

Ganoderic acid Df,a new triterpenoid with aldose reductase inhibitory activity from the fruiting body of Ganoderma lucidum

Ganoderic acid Df, a new lanostane-type triterpenoid, was isolated from the fruiting body of Ganoderma lucidum. Its structure was characterized as 7β, 11β-dihydroxy-3, 15, 23-trioxo-5α-lanosta-8-en-26-oic acid by 1D- and 2D-NMR spectra. This compound exhibited potent human aldose reductase inhibitory activity, with an IC₅₀ of 22.8 μM in vitro. A carboxyl group of this compound's side chain is essential for eliciting inhibitory activity because its methyl ester is much less active.     

Efficacy of koi herpesvirus DNA vaccine administration by immersion method on Cyprinus carpio field scale culture

Koi herpesvirus specifically infects and causes mass mortality on koi and carp, resulting in severe economic losses. In this study, we presented the efficacy of KHV DNA vaccine administration by immersion method on Cyprinus carpio. Two different immersion densities of fish were applied, namely 800 fish L^?1 and 1200 fish L^?1. Thirty‐day‐old common carp juveniles were immersed for 30 min in the water containing 1.3 × 10⁸ CFU mL^?1 of heat‐killed Escherichia coli carrying DNA vaccine encoding glycoprotein‐25, and without vaccination treatment as controls. The challenge test was performed at 30 days post vaccination by injecting 0.1 mL KHV filtrate (10^?3 of dilution rate). The result showed that higher relative per cent survival of KHV‐challenged fish was obtained in 800 fish L^?1 (P < 0.05). Furthermore, significant specific antibody anti‐KHV response (P < 0.05) was detected on 28 and 36 days post vaccination in 800 and 1200 fish L^?1, respectively, compared to the controls there was no specific antibody detected. In conclusion, the KHV DNA vaccine could provide good protection in common carp against KHV infection, which has practical applications in aquaculture practices.     

Maternal immunity of tilapia broodstock vaccinated with polyvalent vaccine and resistance of their offspring against Streptococcus agalactiae

This study aimed to examine the use of Streptococcus agalactiae polyvalent vaccine in tilapia broodstock and the effect of maternal immunity and resistance on their offspring against S. agalactiae strain. The broodstock was injected with polyvalent vaccine of S. agalactiae at a dose of 10⁸ CFU per fish at 2nd gonadal maturity until spawning. Challenge test was carried out on the offspring at the 5, 10, 15 and 20 days after hatching using NK₁, N₁₇O, N₁₄G, N₃M, N₄M strain respectively and combination of them. We observed immunological parameters in broodstock, eggs and larvae and relative per cent survival (RPS) of larvae after challenged with pathogenic S. agalactiae. The results showed that the leukocytes, phagocytic activity, respiratory burst, lysozyme activity and antibody levels of vaccinated broodstock had higher level compared with unvaccinated broodstock. The high level of the lysozyme activity, antibody levels and recombination activating gene 1 (RAG1) were also observed in eggs and larvae from vaccinated broodstock. Larvae produced from vaccinated broodstock when challenged with variety strain of pathogenic S. agalactiae had RPS value more than 50% until 20 days after hatching. In conclusion, polyvalent vaccine of S. agalactiae administrated in the broodstock could enhance immunity in the broodstock and protect their offspring from pathogenic S. agalactiae.     

On-farm selection for quality and resistance to pest/diseases of cocoa in Sulawesi: (ii) quality and performance of selections against Phytophthora pod rot and vascular-streak dieback

The cocoa industry in Sulawesi, the main region of cocoa production in Indonesia, is threatened by destructive diseases, including vascular-streak dieback (VSD) caused by the basidiomycete Oncobasidium theobromae and stem canker and Phytophthora pod rot (PPR) or black pod, caused by Phytophthora palmivora. Using the considerable genetic diversity of cocoa on farms, host resistance was identified and tested with the participation of farmers. Forty-nine local and international cocoa selections with promising resistance characteristics (as well as susceptible controls) were side-grafted onto mature cocoa in a replicated trial with single-tree plots. Developing grafts were assessed in the dry season for severity of VSD infection, scored from 0 (no infection) to 4 (graft death). All of the 49 clones in the trial became infected with VSD in at least some replicates. Average severity varied from 0.2 to 1.6. Potential VSD-resistance was found in eight clones, including DRC 15, KA2 106 and a local Sulawesi selection, VSD2Ldg. Some of the most susceptible clones were local Sulawesi selections from areas with a history of little or no VSD. Thirty-four pod-bearing clones were evaluated over a 2-year period for yield, quality and resistance to natural infections of PPR. Cumulative PPR incidence for all clones was 22% but varied from 8.6 to 43% among clones. Clones with less than 15% PPR incidence were designated as resistant, including DRC 16 and local Sulawesi selections, Aryadi 1, Aryadi 3 and VSD1Ldg. Scavina 12 was moderately resistant in the trial with a PPR incidence of 23%. Cumulative incidences of the mirid, Helopeltis spp., determined in the same evaluation period, indicated that DRC16 was the most susceptible clone with an incidence of 52% in ripe pods and 23% in immature pods. In comparison, KKM4 showed evidence of resistance to Helopeltis spp., with incidences of 34 and 0.8% in ripe and immature pods, respectively. The impact of diseases and pests (including cocoa pod borer) on bean losses and bean quality varied between clones but generally the bean size (or bean count) was affected more than the fat content or shell content.