Vol. 19 No. 4 (2012): December 2012

Distribution of fish in river is controlled by physico-chemical properties of the water which is affected by land-use complexity and intensity of human intervention. A study on fish distribution was carried out in the upper Citarum River to map the effects of physio-chemical properties on habitat use. A survey was conducted to collect fish and to measure the water quality both on dry and rainy season. The result showed that distribution of the fish, in general, represented their adaptive response to physico-chemical properties. The river environment could be grouped into two categories: (i) clean and relatively unpolluted sites, which associated with high DO and water current, and (ii) polluted sites characterized by low DO, high COD, BOD, water temperature, NO3, PO4, H2S, NH3, and surfactant. Fish inhabiting the first sites were Xiphophorus helleri, Punctius binotatus, Xiphophorus maculatus, and Oreochromis mossambicus. Meanwhile, the latter sites were inhabited by Liposarcus pardalis, Trichogaster trichopterus, and Poecilia reticulata. Knowledge about fish distribution in association with the pysico-chemical properties of water is crucial especially for the river management.

Mercury is one of the major pollutant in the environment which is highly toxic. Bioremediation strategies using bacteria have been proposed as an attractive alternative because this is effective, less expensive and more efficient to remove mercury. Brevundimonas sp. HgP1 and Brevundimonas sp. HgP2 were two highly mercury resistant bacteria isolated from a gold mine in Pongkor village with MIC of 575 ppm. The purposes of the research were to study the effect of mercury on bacterial growth and morphological changes of bacterial colony and to measure the ability of bacterial isolates to accumulate Hg2+. The growth was monitored by measuring optical density at 600 nm, whereas accumulation of Hg2+ was measured by mercury vaporation unit. This present studies revealed that the addition of 50 and 100 ppm HgCl2 in Brevundimonas sp. HgP1 resulted in the decreasing of growth rate and the elongation of lag phase in 8 and 16 hours, respectively. The addition of HgCl2 also affected morphological appearance of the bacterial colony to black. Brevundimonas sp. HgP1 accumulated  Hg2+  up to 1.09 and 2.7 mg/g dry weight of cells and removed  64.38 and 57.10% Hg2+  from the medium containing 50 and 100 ppm HgCl2, respectively.

Xanthomonas oryzae pv. oryzae (Xoo), a causal agent of bacterial leaf blight (BLB), is one of the most important pathogens of rice. The effectiveness of ten Streptomyces spp. isolates in suppressing Xoo disease was assessed in planta and in vitro. In planta experiments were carried out in a greenhouse and arranged in a randomized completely block design (RCBD) with three replications. Twenty treatments were tested which included plants inoculated with both Streptomyces spp. and Xoo, and plants inoculated with only Streptomyces spp. Plants inoculated with Xoo and sprayed with a chemical bactericide, and plants inoculated with only Xoo served as positive controls, whereas plants not inoculated with either Streptomyces spp. or Xoo were used as negative controls. The results showed that the effect of endophytic Streptomyces spp. on BLB disease expressed as area under disease progress curve (AUDPC) was not significantly different to that on control plants (P > 0.05). However, plants inoculated with endophytic Streptomyces spp. were significantly taller and produced higher tiller number than control plants (P < 0.05). Streptomyces spp. isolate AB131-1 gave the highest plant height. In vitro studies on biocontrol mechanisms of selected Streptomyces spp. isolates showed that isolate LBR02 gave the highest inhibition activity on Xoo growth, followed by AB131-1 and AB131-2. Two isolates (AB131-1 and LBR02) were able to produce chitinase, phosphatase, and siderophore which included biocontrol characteristics. Morphological and colonization studies under SEM and light microscopy confirmed that the three isolates were endophytic Streptomyces spp. from different species. These studies found that the paddy plant which was inoculated with endophytic Streptomyces spp. AB131-1 and infected by Xoo could increase the height of plant and number of tillers.

Effect of phospholipids on survival and molting synchronicity of mud crab larvae Scylla serrata were examined using Artemia enriched with five treatments of emulsion oil i.e. treatment with different level of soybean lecithin (SL) together with a level of DHA70G (referred to as DHA-SL0, 20 and 40) and treatment with SL and cuttle fish phospholipids (CPL) at 40 uL/L without DHA70G (referred to as WDHA-SL and WDHA-CPL). Survival rate, intermolt period, carapace width, and molting synchronicity were evaluated. Additionally, lipid classes and fatty acid composition of enriched Artemia were analyzed. Survival rate, intermolt period, and carapace width at the first crab (FC) stage of mud crab larvae fed DHA-SL0 to 40 were similar to that of WDHA-CPL but higher than that of WDHA-SL (P < 0.05). Moreover, mud crab larvae fed DHA-SL20, DHA-SL40, and WDHA-CPL had a significantly higher molting synchronicity index compared to that of larvae fed WDHA-SL and DHA-SL0. It can be concluded that combination of phospholipids and essential fatty acids exhibited an additive effect in improving molting synchronicity of mud crab larvae.

Two clones of N1 gene derived from isolate A/Dk/Tangerang/Bbalitvet-ACIAR-TE11/2007 (H5N1) exhibit single mismatch of amino acid sequence at position 242 that is threonine and methionine for the clone #3 and #5, respectively. In order to evaluate the effect of the amino acid substitution, these clones were inserted into two different expression vectors that are pEGFP-C1 and pcDNA-3.3 TOPO® TA cloning. Subsequently, the respective recombinant clones were transfected into eukaryotic cells, including CEF, RK13 and VERO using Lipofectamine ‘plus’ reagent. As a result, the clone #3 retaining atypical sequence showed lower expression level rather than the clone #15 in both vectors and all type of cells. The 3D conformational modelling revealed that the mutation occurs in the inner part of glycoprotein embedded within envelope or matrix. Therefore, the missense mutation seems has no effect on the antigenic properties of neuraminidase but this substitution by any means causes lethal mutagenesis in the individual gene expression by reducing level of protein transcript.

The prevalence of V.ovalifolium in Pulau Dua Nature Reserve was surveyed. This parasite was observed parasitizing on only two host species, Excoecaria agallocha and Thespesia populnea, among 11 potential host tree species in the study area. This phenomenon, contemporarily coined as local host specificity, is complementary to a small endnote on Backer & Bakhuizen van den Brink’s 1965 Flora of Java vol. II. V.ovalifolium’s prevalence is higher as the increase on host tree DBH, as the decrease of infested host branch diameter and as the increase of host tree branching order. Two later findings point at Dicaeum trochileum as V.ovalifolium seed disperser among 90 bird species living on the nature reserve.

Visually identifying the sex of a bird can be difficult. It cannot be done in half the world’s species when they are adults, and virtually none can be sexed as chicks. Despite this, the sex of a bird is vital for captive breeding. An increased number of birds are being sexed using DNA amplification techniques. In this approach, the CHD-W and CHD-Z are distinguished by the amplification of an intron present in both genes. PCR products on the gel electrophoresis vary in size revealing one band in males at the CHD-Z, and two bands in females corresponding to both the CHD-W and CHD-Z. Two independent sets of primer (P8/P2 and 2550F/2718R) were used to amplify the CHD gene region from both the Z and W chromosome. One hundred and ten (110) birds were sexed using first pair of primers: (P8/P2). Sexing results indicated that 81.8% were successfully determined, 12.7% failed to be amplified and 5.5%  were not perfectly determined because the PCR products showed thick band. The thick band caused misidentified female to male birds. An alternative primer (2550F/2718R) was applied to solve the problem. Two hundreds and twenty-nine birds were sexed and the results showed 100% successfully determined. From this study, it is suggested to use a pair of 2550F and 2718R primers for distinguishing a male from a female bird.