Nutrient Deficiencies Impact on the Cellular and Metabolic Responses of Saxitoxin Producing Alexandrium minutum: A Transcriptomic Perspective

Dinoflagellate Alexandrium minutum Halim is commonly associated with harmful algal blooms (HABs) in tropical marine waters due to its saxitoxin production. However, limited information is available regarding the cellular and metabolic changes of A. minutum in nutrient-deficient environments. To fill this gap, our study aimed to investigate the transcriptomic responses of A. minutum under nitrogen and phosphorus deficiency. The induction of nitrogen and phosphorus deficiency resulted in the identification of 1049 and 763 differently expressed genes (DEGs), respectively. Further analysis using gene set enrichment analysis (GSEA) revealed 702 and 1251 enriched gene ontology (GO) terms associated with nitrogen and phosphorus deficiency, respectively. Our results indicate that in laboratory cultures, nitrogen deficiency primarily affects meiosis, carbohydrate catabolism, ammonium assimilation, ion homeostasis, and protein kinase activity. On the other hand, phosphorus deficiency primarily affects the carbon metabolic response, cellular ion transfer, actin-dependent cell movement, signalling pathways, and protein recycling. Our study provides valuable insights into biological processes and genes regulating A. minutum's response to nutrient deficiencies, furthering our understanding of the ecophysiological response of HABs to environmental change.

Genome Sequencing and Analysis of Trichoderma (Hypocreaceae) Isolates Exhibiting Antagonistic Activity against the Papaya Dieback Pathogen, Erwinia mallotivora

Erwinia mallotivora, the causal agent of papaya dieback disease, is a devastating pathogen that has caused a tremendous decrease in Malaysian papaya export and affected papaya crops in neighbouring countries. A few studies on bacterial species capable of suppressing E. mallotivora have been reported, but the availability of antagonistic fungi remains unknown. In this study, mycelial suspensions from five rhizospheric Trichoderma isolates of Malaysian origin were found to exhibit notable antagonisms against E. mallotivora during co-cultivation. We further characterised three isolates, Trichoderma koningiopsis UKM-M-UW RA5, UKM-M-UW RA6, and UKM-M-UW RA3a, that showed significant growth inhibition zones on plate-based inhibition assays. A study of the genomes of the three strains through a combination of Oxford nanopore and Illumina sequencing technologies highlighted potential secondary metabolite pathways that might underpin their antimicrobial properties. Based on these findings, the fungal isolates are proven to be useful as potential biological control agents against E. mallotivora, and the genomic data opens possibilities to further explore the underlying molecular mechanisms behind their antimicrobial activity, with potential synthetic biology applications.

Pathogenic hitchhiker diversity on international ships' ballast water at West Malaysia port

This study investigates bacterial diversity and potential pathogens in the international ships' ballast water at Tanjung Pelepas Port, Malaysia, using 16S rRNA amplicon sequencing. Thirty-four bacterial phylum, 305 families, 577 genera, and 941 species were detected in eight ballast water samples of different origins. The similarity of the bacterial composition between samples was found to be random and not tied to geographical locations. The bacterial abundance did not seem to be affected by related physicochemical except for temperature. Ballast water samples with a temperature lower than 25 °C showed a relatively lower bacterial abundance. A total of 33 potential pathogens were detected from all ballast water samples. Pseudomonas spp., Tenacibaculum spp., Flavobacteriaceae spp., Halomonas spp., and Acinetobacter junii are the potential pathogens with more than 10% OTU prevalence. This study would provide beneficial information for further enhancing ballast water microorganism guidelines in Malaysia.

Stingless Bee Honey: Evaluating Its Antibacterial Activity and Bacterial Diversity

Stingless bee honey (SBH) is an astounding 'miracle liquid' with countless medicinal properties for various diseases such as gastroenteritis, cataracts, as well as for wound-healing. However, knowledge regarding it is still rather scarce. Henceforth, it is intriguing for us to contemplate on the less-studied stingless bee and its honey in particular. First and foremost, the antimicrobial ability of honey from eight different stingless bee species was tested to further proven its health benefit. Homotrigona fimbriata honey showed the highest antimicrobial activity with inhibition against five bacteria; Serratia marcescens, Escherichia coli, Bacillus subtilis, Alcaligenes faecalis and Staphylococcus aureus. The next aim of our study is to characterize their honey bacterial community via the use of 16S rRNA amplicon sequencing technology. A total of eight bacterial phyla, 71 families, 155 genera and 70 species were identified from our study and two of the stingless bee species honey were determined to have the highest bacterial diversity compared to other six stingless bee species, namely Heterotrigona erythrogastra and Tetrigona melanoleuca. Furthermost, Lactobacillus malefermentans was thought to be the native dominant bacteria of SBH due to its predominant presence throughout all studied species. The aforementioned SBH's antimicrobial results and characterization study of its bacterial diversity are hoped to carve the pathway towards extending its probiotic ability into our everyday lives.

Biosynthesis of Saxitoxin in Marine Dinoflagellates: An Omics Perspective

Saxitoxin is an alkaloid neurotoxin originally isolated from the clam Saxidomus giganteus in 1957. This group of neurotoxins is produced by several species of freshwater cyanobacteria and marine dinoflagellates. The saxitoxin biosynthesis pathway was described for the first time in the 1980s and, since then, it was studied in more than seven cyanobacterial genera, comprising 26 genes that form a cluster ranging from 25.7 kb to 35 kb in sequence length. Due to the complexity of the genomic landscape, saxitoxin biosynthesis in dinoflagellates remains unknown. In order to reveal and understand the dynamics of the activity in such impressive unicellular organisms with a complex genome, a strategy that can carefully engage them in a systems view is necessary. Advances in omics technology (the collective tools of biological sciences) facilitated high-throughput studies of the genome, transcriptome, proteome, and metabolome of dinoflagellates. The omics approach was utilized to address saxitoxin-producing dinoflagellates in response to environmental stresses to improve understanding of dinoflagellates gene–environment interactions. Therefore, in this review, the progress in understanding dinoflagellate saxitoxin biosynthesis using an omics approach is emphasized. Further potential applications of metabolomics and genomics to unravel novel insights into saxitoxin biosynthesis in dinoflagellates are also reviewed.

Effect of pellet from total mixed ration on growth performance, blood metabolomics, carcass and meat characteristics of Bangladeshi garole sheep

Six indigenous Bangladeshi Garole sheep (Ovis aries) (BW: 8±0.5 kg; Age: 1yr) were divided into two groups using a randomized block design to investigate the effect of total mixed ration (TMR) pellet feeding on growth parameter, blood metabolomics, carcass and meat characteristics. Control diet was composed of road side grass, rice straw, wheat bran, mustard oil cake, molasses, common salt which considered as loose total mixed ration (L-TMR) and treatment diet was pelleted form of L-TMR (P-TMR).In both the dietary treatments the animals were fed at 1.5 times of maintenance energy and protein requirement. P-TMR revealed a positive impact (p < 0.05) on live weight gain and feed conversion ratio than L-TMR. Total digestible nutrients (TDN) and digestible crude fibre (DCF) was significantly higher (p < 0.05) in P-TMR group whereas there was no significant difference (p < 0.05) in other digestible nutrients as well as plasma metabolites like plasma glucose, triglyceride, total cholesterol, HDL-cholesterol and LDL- cholesterol concentration between two dietary group. Dressing percentage and eye muscle area was significantly higher (p < 0.05) in P-TMR group but no significant difference was found between dietary treatments in term of disposition of body fat, proximate composition of mutton, all the sensory parameters except tenderness and overall acceptability. So, it could be concluded that, the P-TMR might be fed to sheep for better growth performance and higher meat production rather than production of functional mutton.Progressive Agriculture 28 (3): 222-229, 2017 

Further Insight into the Definite Morphology and Formation Mechanism of Mesoporous Silica KCC-1

The unique three-dimensional pore structure of KCC-1 has attracted significant attention and has proven to be different compared to other conventional mesoporous silica such as the MCM-41 family, SBA-15, or even MSN nanoparticles. In this research, we carefully examine the morphology of KCC-1 to define more appropriate nomenclature. We also propose a formation mechanism of KCC-1 based on our experimental evidence. Herein, the KCC-1 morphology was interpreted mainly on the basis of compiling all observation and information taken from SEM and TEM images. Further analysis on TEM images was carried out. The gray value intensity profile was derived from TEM images in order to determine the specific pattern of this unique morphology that is found to be clearly different from that of other types of porous spherical-like morphologies. On the basis of these results, the KCC-1 morphology would be more appropriately reclassified as bicontinuous concentric lamellar morphology. Some physical characteristics such as the origin of emulsion, electrical conductivity, and the local structure of water molecules in the KCC-1 emulsion were disclosed to reveal the formation mechanism of KCC-1. The origin of the KCC-1 emulsion was characterized by the observation of the Tyndall effect, conductometry to determine the critical micelle concentration, and Raman spectroscopy. In addition, the morphological evolution study during KCC-1 synthesis completes the portrait of the formation of mesoporous silica KCC-1.

Plasma lipid profile of mice fed diet supplemented with broiler fat

This study was conducted with 180 female Swiss albino mice to examine the effects of supplementing broiler fat in the diets of mice on blood lipid profile. Twenty one days old mice were collected from ICDDRB, Mohakhali, Dhaka. They were randomly distributed in four groups having three replications each. Each replicate group had 15 mice. Results revealed that supplementation of broiler fat in mice diet significantly changed (p<0.05) triglyceride (TG) and low density lipoprotein (LDL) among groups. The control group (T0) had the highest level of cholesterol and LDL. Cholesterol, TG and LDL markedly increased (p<0.05) in all dietary treatment groups, while high density lipoprotein (HDL) significantly (p<0.01) decreased after supplementation of experimental diets. It was concluded that all the dietary treatments in general increased blood cholesterol, TG and LDL in mice fed broiler fat with different oil supplements. However, the soybean and palm oil group was comparatively better than other groups in respect of cholesterol, HDL and LDL at the blood lipid profile of mice. Therefore, it can be concluded that consumption of broiler fat with soybean and palm oil could be less harmful for mice.DOI: http://dx.doi.org/10.3329/bjas.v43i1.19380 Bang. J. Anim. Sci. 2014. 43 (1): 21-24

In vitro antimicrobial activities of different fractions of Swertia chirata ethanolic extract

The aim of the present study was to evaluate the in vitro antimicrobial activity of pet-ether, dichloromethane and methanol fractions of Swertia chirata (Family: Gentianaceae) ethanolic extract. Disc diffusion technique and food poison method were used for antibacterial and antifungal activity, respectively. Dichloromethane fraction from both leaf and stem showed significant antimicrobial activities against some Gram-positive and Gram-negative bacteria and mild to moderate activity against some fungi. A large zone of inhibition was observed (19 mm) against Staphylococcus aureus. Test materials at a concentration of 400 microg disc(-1) were used to evaluate the antimicrobial activity while Kanamycin at a concentration of 30 microg disc(-1) was used as positive control in this study. Among different fractions, dichloromethane fraction showed significant antimicrobial activity against Gram-positive, Gram-negative and fungi. The most significant antimicrobial activity was seen against Staphylococcus aureus which reflects it potentiality to be used in skin infections.

Effect of dietary citric acid, flavomycin and their combination on the performance, tibia ash and immune status of broiler

The goal of this research was to investigate the effect of citric acid (CA), the antibiotic growth promoter flavomycin (FL) and their combination on the growth performance, tibia ash and immune status of broilers. One hundred and sixty straight run day-old broiler chicks (Hubbard Classic) were randomly distributed into four dietary groups, with four replicate cages having 10 birds in each. Standard corn-soybean-based basal starter diet was given to control birds. Diets for other groups were further fortified by 0.5% CA, 0.001% FL and their combination (0.5% CA plus 0.001% FL). On day 35, CA and its combination (CA + FL) group had 17 and 12% increase in live weight compared with control, respectively (P < 0.05). Total live weight on day 35 was 1141, 1337, 1169, and 1275 g bird-1 in different groups, respectively (P < 0.05). Cumulative feed intake was higher (P < 0.05) in CA and its combination (CA + FL) compared with the control and FL groups on day 28. Supplementation with CA improved (P > 0.05) feed conversion ratio [FCR; feed intake (kg):weight gain (kg)] compared with FL and its combination (CA + FL). Carcass yield was increased (P > 0.05) due to the addition of CA and its combination (CA + FL). Tibia ash content in the CA group (59.0) was higher (P < 0.05) than in the control (53.6%), FL (53.1%) and their combination (57.1%). The lymphocyte cells associated with immunity in the lymphoid organs (caecal tonsil, bursa Fabricius and ileum) were more densely populated, suggesting an increased level of innate immunity in the CA group. Overall mortality was low (1.25%), and there were no treatment-related effects on mortality. Citric acid reduced the pH of formulated feeds, but mild reduction was found in the pH of the faeces. Dietary supplementation of 0.5% CA increase weight gain, feed intake, tibia ash deposition and non-specific immunity (P < 0.05) as well as feed efficiency and carcass yield (P > 0.05) of broilers. Citric acid has potential as a growth promoter to replace the antibiotic growth promoter FL.Key words: Citric acid, flavomycin, growth performance, immunity, tibia ash, broiler

Evaluation of a dot-immunoblot assay for detecting leishmanial antigen in naturally infected Phlebotomus argentipes (Diptera: Psychodidae)

A simple and highly reproducible dot-immunoblot assay was developed to detect leishmanial antigen in Phlebotomus argentipes that were naturally infected with Leishmania donovani. The test was sensitive to as little as 10 ng of antigenic protein (equivalent to the gut content of one laboratory-infected sandfly) and also appeared to be specific, in that it gave a positive result with some P. argentipes (the primary vector of L. donovani in India) and L. donovani but not with P. papatasi or other pathogens. When used to investigate a large number of sandflies collected from two areas of the Indian state of Bihar where visceral leishmaniasis is endemic, the assay appeared sufficiently sensitive and specific to detect the naturally infected insects. The simplicity, reproducibility, high sensitivity and high specificity of the assay should make it useful for field studies, particularly in determining the prevalence of sandfly infection, the local level of transmission, and the impact of vector-control programmes.

Infection of human mononuclear phagocytes and macrophage-like THP1 cells with Leishmania donovani results in modulation of expression of a subset of chemokines and a chemokine receptor

The expression of chemokines and chemokine receptors was studied in Leishmania donovani (LD)-infected human mononuclear phagocytes and the human monocytic cell line THP1. Our studies showed that LD infection caused the upregulation of three beta chemokines (macrophage inflammatory protein-1 alpha (MIP-1alpha), MIP-1beta and RANTES (regulated on activation normal T cell expressed and secreted)), one alpha chemokine (interleukin-8 (IL-8)) and the CC chemokine receptor 5 (CCR5) but not CCR1, as evident from reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. The CCR5 upregulation in human mononuclear phagocytes and THP1 cells was also evident by confocal microscopy. The possible association of such upregulation in relation to Leishmania and human immunodeficiency virus (HIV) coinfection was discussed.

Isolated splenic metastasis from carcinoma of the breast

A case of isolated splenic metastasis from carcinoma of the breast in a 54 year old woman, two years after treatment for breast carcinoma, is presented. There was no involvement of other organs like liver, bone, lungs, etc. The patient underwent splenectomy and recovered without any complications. This case is being reported because of the rarity of the lesion.

Effect of feeding and body condition score on multiple ovulation and embryo production in zebu cows

The aim of this study was to standardize the feeding regimen and the body condition score (BCS) for maximum superovulatory responses in indigenous zebu cows. Ten regularly cycling 5-8-year-old dry cows, weighing 176--260 kg with BCS 2.5--4.5 were divided into two equal groups at random. The groups were maintained on either a good-nutrition or a high-nutrition diet. The feedstuffs were analysed by proximate feed analysis and the metabolizable energy content was estimated. After 3 months feeding, individual cows were injected (i.m) with 1500 IU pregnant mare's serum gonadotrophin (PMSG) at day 10 or day 11 of the oestrous cycle (day of oestrus = day 0). Alfaprostol (6 mg) was injected (i.m) 48 h after the injection of PMSG to induce oestrus. At day 6 or day 7 (day of insemination = day 1), the contents of individual uterine horns were flushed with 150-200 ml of phosphate-buffered saline + 0.2% bovine serum albumin using a two-way Foley catheter. The embryos were identified, evaluated and graded as excellent, good, fair or poor under a stereomicroscope. For the good- and high-nutrition diets, the daily intake of green grass, straw, concentrate, dry matter, crude protein and estimated metabolizable energy by individual cows were 5 and 6 kg, 3 and 3 kg, 1.5 and 3.5 kg, 4.87 and 6.82 kg, 0.39 and 0.74 kg, and 39.60 and 59.12 MJ, respectively. The protein content was 8 and 11% in the good- and high-nutrition diets, respectively. The two groups of cows on different nutritional diets differed significantly with regard to body weight, body condition score and number of palpated corpora lutea (p < 0.01). For cows on the good-nutrition diet, the median number of recovered embryos and transferable quality embryos were three and two, respectively. The recovery rate of embryos was 79.30% of palpated corpora lutea. Cows on the high-nutrition diet did not yield any embryos. The indigenous zebu cows fed on the good-nutrition diet with BCS 2.5-3 were considered suitable for the induction of superovulation, the cows on the high-nutrition diet with BCS 4-4.5 were unsatisfactory and were more prone to cyst formation in the ovaries.

Artificial Brassica napus flowering in Bangladesh

Natural rapeseed (Brassica napus L.; AACC 2n=38), originated in the temperate climate of the Southwest European Mediterranean region, fails to complete its generative phase in the subtropics and is thus not cultivated in countries like Bangladesh. Adapted agroecotypes are available from the diploid representatives of its genome A (B. campestris/pekinensis, 2n=20) and C (B. oleracea/alboglabra, 2n=18). An artificial resynthesis based on carefully selected progenitor lines was expected to give a photoperiodically better adapted rapeseed. ♀ B. pekinensis x ♂ B. oleracea/alboglabra gave 2 hybrids and 87 matromorphous plants from 1,448 crossed flowers and the reciprocal combination gave no hybrid but 11 matromorphous plants from 2,228 pollinated flowers. The two true hybrids were vegetatively propagated and chromosome doubled. Part of the F2 was grown in Sweden (all plants flowered and the most early ones were selected), part in Bangladesh (13 out of 706 plants flowered). The selected F3 material flowered in Bangladesh and transgressions in earliness could be recorded, some lines were of definite agronomic potential. A correlation in earliness between reaction in Sweden (long day) and Bangladesh (short day) was observed.

Propionic Acid Is An Alternative To Antibiotics In Poultry Diet

Propionic acid (PA) is a fungicide and bactericide, registered to control fungi and bacteria in stored grains, hay, grain storage areas, poultry litter, and drinking water for livestock and poultry. European Union (EU) certifies PA as the great of grain preserver and most efficient in controlling Salmonella and other pathogens. Recently it is used as feed additive in poultry and non-ruminant production. Suitable inclusion level of PA is 0.2 to 0.4% which can improve the overall performances of poultry. The preservative effect of PA is due to its antibacterial and mould inhibitory effect. High bacteriostatic property of PA is due to its pH reduction activity both in feed and gastrointestinal tract through pharmacogenic action on microflora. Propionic acidA with its growth promoting, health enhancing and antimicrobial effect has proven to be an effective alternative to antibiotic growth promoters in food animal production. DOI: http://dx.doi.org/10.3329/bjas.v38i1-2.9920 BJAS 2009; 38(1-2): 115-122