Potential use of selected citrus rootstocks and interstocks against HLB disease in Malaysia

Huanglongbing (HLB), also known as citrus greening disease, has spread to and is seriously threatening the citrus industry in more than 40 countries. The HLB pathogen is a phloem limited bacteria, Candidatus Liberibacter spp. There is little information pertaining to the effects of different citrus rootstocks and interstocks against HLB in Citrus reticulata. The objective of this study was to evaluate the beneficial effects of different combinations of citrus rootstocks and interstocks against HLB using side grafting. There were no symptoms of HLB when C. grandis was used as rootstock with C. hystrix as the interstock and vice versa six months after inoculation. However, C. Liberbribacter asiaticus was detected in the scion using second PCR amplification. A high rate of disease severity was observed when C. aurantum was used as rootstock and C. aurantifolia as the interstock and vice versa. This study showed that C. Liberibacter asiaticus can be detected by conventional PCR and characteristics of their detrimental effects include low rate of vegetative growth and reduction of dry matter, root dry matter, plant height and stem diameter.     

Osteoarthritis in the cat: 2. how should it be managed and treated?

PRACTICAL RELEVANCE: Osteoarthritis (OA) is very common in the cat and in many cases is associated with significant long-term pain, which limits mobility and activity, and severely compromises the animal's quality of life. CLINICAL CHALLENGES: The treatment of chronic arthritic pain is a major challenge and many analgesic drugs used in other species are not licensed, not available or not tested for use in the cat. Many older cats with painful OA have some degree of chronic kidney disease (CKD) and many clinicians are reluctant to use non-steroidal anti-inflammatory drugs (NSAIDs) in these animals because of the potential for nephrotoxicity. EVIDENCE BASE: There are several publications that show that meloxicam is an effective NSAID for the cat and can be used long-term. It is easy to administer and there is published evidence that meloxicam can actually slow the progression of CKD in this species. Many other drugs are used to treat chronic pain in the cat but there is no documented evidence of their efficacy in OA. Unlike the dog, there is limited evidence for the effectiveness of omega-3 fatty acid-rich diets in managing feline OA and further work is required. There is no published data as yet for the usefulness or otherwise of nutraceuticals (glucosamine and chondroitin) in managing feline OA; studies in the authors' clinic suggest some pain-relieving effect. Research into environmental enrichment as a way of improving quality of life in cats with painful OA is lacking, but it is an approach worth using where possible. Modifications to the environment (eg, provision of comfortable bedding and ramps) are also important.     

Plasma sex steroid hormonal profile and gonad histology during the annual reproductive cycle of river catfish Hemibagrus nemurus (Valenciennes, 1840) in captivity

Plasma sex steroid hormonal profile and gonad histology were correlated to study the annual reproductive cycle of Hemibagrus nemurus. Hormones were measured by Enzyme Linked Immunosorbent Assay. Gonad tissues were observed by using light microscopy. The highest testosterone (T) value for male was observed in November and that of female was in October. 11-ketotestosterone (11-KT) and 17β-estradiol (E2) levels were highest in June and November, respectively. Hormonal profiles of T, 11-KT and E2 showed several peaks which indicated a non-seasonal pattern. There were significant differences (p < 0.05) in the monthly levels of T, 11-KT and E2. Gonadosomatic index of H. nemurus ranged from 1.14 ± 0.02 % to 7.06 ± 1.40 %, and high gonadosomatic indices were recorded in May, August and November. Gonad histology revealed that spermatozoa were always present in the testes which implied continuous spermatogenesis and asynchronous ovarian development pattern was observed in the ovaries. The annual reproductive cycle of H. nemurus did not show a seasonal pattern and this indicate that H. nemurus is a non-seasonal breeder with several spawning cycles and can be referred to as indeterminate batch spawner. The major significances of this study are annual sex steroid hormonal profile and asynchronous ovarian development of H. nemurus. This information will contribute to our knowledge of reproductive biology of H. nemurus.     

Determination of some heavy metal concentrations in razor clam (Solen brevis) from Tanjung Lumpur coastal waters, Pahang, Malaysia

An effort to analyze selected heavy metal accumulation by the razor clam (Solen brevis) from Tanjung Lumpur was conducted on January to April 2010. A total of fifty individuals of Razor clam Solen brevis were sampled and metals such as Iron (Fe), Zinc (Zn), Copper (Cu), Manganese (Mn), Lead (Pb) and Cadmium (Cd) Concentrations were determined using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Among the metals Fe occurred in elevated concentration in the soft tissue of razor clam followed by Zn. Cd was found to be in least concentration in the sample. Mean concentration of Fe, Zn, Mn, Cu, Cd and Pb in the soft tissue were 415.2 +/- 56.52, 87.74 +/- 11.85, 18.71 +/- 2.10, 8.64 +/- 1.75, 0.67 +/- 0.29 and 1.61 +/- 0.45 microg g(-1) dw, respectively indicating that the bioaccumulation of essential metals in the soft tissue was greater than the non essential heavy metals. Metal accumulation in the soft tissue of razor clam followed Fe > Zn > Mn > Cu > Pb > Cd order in present study. The observed concentration of acute toxicity of metals in Solen brevis (Family: Solenidae) from Tanjung Lumpur Coastal waters was lower than the permissible limit recommended by National and international standards proved that this species could be utilized for human consumption.     

Effects of temperature and hydrogen peroxide on mycelial growth of eight Pleurotus strains

Effective use of hydrogen peroxide as a chemical sterilant in mushroom production and selection of cultivable mushroom strains for tropical conditions require knowledge of the genetic diversity in the tolerance of the strains to hydrogen peroxide and to high temperatures. Therefore, three experiments were conducted to examine the sensitivity of Pleurotus mycelium to temperature and hydrogen peroxide. In Experiment 1, eight Pleurotus strains, which included two Pleurotus sajor-caju strains, three Pleurotus ostreatus strains, Pleurotus salmoneo stramineus, Pleurotus cornicopae and Pleurotus eryngii were cultured aseptically on agar at 25, 30 and or 35 °C. In Experiment 2, the eight strains were cultured aseptically on agar at six hydrogen peroxide concentrations (0–0.1%, v/v) at 27 °C. In Experiment 3, P. sajor-caju strain 1, a fast growing strain, was cultured non-asceptically at six hydrogen peroxide concentrations (0–0.1%, v/v) at 27 °C. In Experiment 1, mycelial growth was maximal at 25–30 °C, whereas a temperature of 35 °C was detrimental to mycelial growth except in one strain. At the highest temperature tested (35 °C), the relative mycelial growth rate (% of maximum) ranged from 6 to 91%, indicating marked differences in tolerance of the strains to high temperature. In Experiment 2, the mycelial growth rate in all strains increased when hydrogen peroxide was increased from 0 to 0.001% (v/v), and then decreased with further increments in hydrogen peroxide concentration. The strains differed markedly in sensitivity to hydrogen peroxide. The hydrogen peroxide concentration associated with 50% reduction in maximum mycelial growth rate due to toxicity (EC₅₀) ranged from 0.009 to 0.045% (v/v). It was noted that P. sajor-caju strain 1 which was the most tolerant strain to high temperature was also the most tolerant to high hydrogen peroxide concentration. In Experiment 3, involving non-aseptic culture of P. sajor-caju strain 1, bacterial growth was observed at concentrations ≤0.016%, whilst the upper hydrogen peroxide concentration limit for fungal growth was 0.025% (v/v). The highest hydrogen peroxide concentrations 0.016% (v/v) and 0.025% (v/v) in which bacteria and fungi, respectively, were observed to grow were within the concentration range 0.009–0.028% (v/v) that was found in Experiment 2 to cause a 50% reduction in mycelia growth in six of the eight Pleurotus strains tested. Use of hydrogen peroxide as a chemical sterilant in conjunction with strains highly tolerant of its toxicity offers a very cheap method of producing spawn as well as the mushrooms, and opens up opportunities for poor rural people.     

Phytoplankton succession in intensive marine shrimp culture ponds treated with a commercial bacterial product

Succession of phytoplankton dominance was studied in shrimp culture ponds treated with commercial bacterial products. Diatoms were dominant and the cyanobacteria were absent in both treated and control ponds at the beginning of the culture period. After 34 days, the diatoms significantly decreased whereas cyanobacteria increased in both ponds. Chlorophyll a increased from a mean of 35.56 mg m^?3 in the first phase to 186.00 mg m^?3 in the final phase, and from 42.12 mg m^?3 to 242.81 mg m^?3 in the treated and control ponds respectively. Cyanobacteria were significantly higher in the control compared with the treated ponds during the final phase of the culture. Algal bioassay showed that the addition of nitrogen either alone or with silica to pond water significantly increased the specific growth rate of Chaetoceros calcitrans. The specific growth rate of Oscillatoria sp. significantly increased when a combination of nitrogen, phosphorus and carbon was added to the pond water. Addition of silica seemed to depress the growth rate of Oscillatoria sp. Nutrient enrichment should be minimized and the supply of nitrogen and silica should be adequate for promoting the growth of beneficial phytoplankton in aquaculture systems.     

First molecular detection of porcine bocavirus in Malaysia

Several strains of porcine bocaviruses have been reported worldwide since their first detection in Sweden in 2009. Subsequently, the virus has been reported to be associated with gastrointestinal and respiratory signs in weaner and grower pigs. Although Malaysia is host to a self-sufficient swine livestock industry, there is no study that describes porcine bocavirus in the country. This report is the first to describe porcine bocavirus (PBoV) in Malaysian swine herds. PBoV was identified in various tissues from sick and runt pigs using the conventional PCR method with primers targeting conserved regions encoding for the nonstructural protein (NS1) gene. Out of 103 samples tested from 17 pigs, 32 samples from 15 pigs were positive for porcine bocavirus. In addition, a higher detection rate was identified from mesenteric lymph nodes (52.9%), followed by tonsil (37.0%), and lungs (33.3%). Pairwise comparison and phylogenetic analyses based on a 658-bp fragment of NS1 gene revealed that the Malaysian PBoV strains are highly similar to PBoV3 isolated in Minnesota, USA. The presence of porcine bocavirus in Malaysia and their phylogenetic bond was marked for the first time by this study. Further studies will establish the molecular epidemiology of PBoV in Malaysia and clarify pathogenicity of the local isolates.     

Case–control study on risk factors associated with Brucella Melitensis in goat farms in Peninsular Malaysia

Caprine brucellosis is a bacterial zoonotic infection affecting goats especially in developing countries all over the world. In Malaysia, the risk factors associated with this infection in farms have not been studied. A case–control study was carried out in goat farms in four states of Malaysia to elucidate the risk factors associated with the infection on the farms using structured questionnaires and face-to-face interviews. Results indicate that the introduction of new animals (OR?=?5.25; 90 % CI?=?1.46, 18.88), younger age category of farms (OR?=?5.53; 90 % CI?=?1.09, 21.66), and farms with single breed of goats (OR?=?8.50; 90 % CI?=?1.27, 41.97) were significant risk factors for brucellosis. In order to control brucellosis or possibly eradicate it in goat farms, these factors need to be dealt with. Enforcing stringent importation protocols or complete ban of goat importation from brucellosis endemic countries will help reduce risk of introducing new infection into the country.     

Influence of the melamine content in melamine-urea-formaldehyde resins on formaldehyde emission and cured resin structure

The effect of melamine content in melamine-urea-formaldehyde (MUF) resins on the formaldehyde emission and resin structure was investigated using six MUF resins synthesized with different F/(M + U) and M/U molar ratios. The formaldehyde emission from the plywood decreased as the F/(M + U) molar ratio decreased and the M/ U molar ratio increased. In addition, the bond performance was enhanced as the M/U molar ratio increased in the MUF resins with a fixed F/(M + U) molar ratio. Quantitative solution¹³C-NMR spectra of MUF resins revealed that the MUF resins with a high melamine content consisted of more highly branched crosslinkage structure and free melamine compared to the resins with low melamine contents. Furthermore, solid-state¹³C CP-MAS NMR spectra of cured MUF resins proved that more methylol groups, dimethylene ether, and branched methylene structures were present in the MUF resins with a higher F/(M + U) molar ratio, leading to increased bond strength and formaldehyde emission. There is no significant difference in the linkage structure of the cured resins with the same F/(M + U) and different M/U molar ratios except the ratios of carbonyl carbon of urea and triazine carbon of melamine. Therefore, the lower formaldehyde emission from cured MUF resins with a higher M/U molar ratio might be ascribed to the stronger linkages between triazine carbons of melamine than those of urea carbons. Consequently, the melamine contributed to strong crosslinking linkages in the cured resin structures, leading to lower formaldehyde emission and better bond performance.Part of this work was presented at the 48th Annual Meeting of the Japan Wood Research Society, Shizuoka, April 1998