Increased Disease Resistance Research Articles

Influence of traditional Chinese medicine and Bacillus species (TCMBS) on growth, immune response and disease resistance in Nile tilapia, Oreochromis niloticus

Multispecies herbs and probiotic bacteria offered to fish might enhance their immune response and increase disease resistance, but the dose effects of herbal-probiotic application remain unclear. Therefore, the effect of herbal-probiotic mixtures of traditional Chinese medicine (TCM) of composition Astragalus membranaceus, Angelica sinensis, Crataegus hupehensis and probiotic Bacillus species (BS) of composition Bacillus subtilis and Bacillus lincheniformis as natural immunostimulants in tilapia Oreochromis niloticus have been investigated. Fish were randomly divided into four groups: control diet (CT), TCMBS1 [TCM at 3 g/kg and BS at 7 g/kg], TCMBS2 [TCM at 5 g/kg and BS at 5 g/kg], TCMBS3 [TCM at 7 g/kg and BS at 3 g/kg]. Tilapia in the TCMBS3 group showed significant improvement in weight gain, specific growth rate, and lowered feed conversion ratio compared with other treated groups and the control. Concerning immune indexes, all treated groups significantly enhanced lysozyme, superoxide dismutase, catalase, protease and antiprotease activities, with highest values in catalase and antiprotease activities in TCMBS3 compared with control. TCMBS3 demonstrated higher expression of βeta-defensin, lysozyme, heat shock protein 70, catalase and transforming growth factor-βeta compared with other treated groups or the control group in both mid-intestines and head-kidney. After challenge with Streptococcus agalactiae, the best survival was found in TCMBS3 (97%), followed by TCMBS2 (73%), and TCMBS1 (69%) compared with the CT (35%). Collectively the present results suggest that TCMBS3 dose might potentiate a higher immune response and disease resistance in fish.

Biosecurity measures on cattle farms

The aim of implementing biosecurity measures on cattle farms is: a) to preserve a high health status of animals by protecting them from new and existing pathogens and b) to ensure the production of safe food. General biosecurity measures should be implemented in any farm regardless of any specific problem. In "open" herds, where cattle have contact with animals from different farms (purchase of breeding animals, participation in cattle shows, common pastures etc) more strict biosecurity measures (i.e., isolation of in-coming animals, clinical examinations, laboratory tests, vaccinations) should be implemented. Therefore, "closed" herds present significant advantages in terms of health management. Moreover, all farms must apply control-restriction measures for visitors and vehicles as well as control and protection measures for feedstuffs and water. Animals of other species (farm or companion animals) should not be kept on the farm, whereas the entry of stray and wild animals must be prevented. Planned control measures for insects, rodents and wild birds are imperative. Management practices, such as grouping according to the age of cattle, but avoiding mixing young with older animals, should be combined with high housing standards, including proper ventilation and frequent manure removal. The implementation of the "all-in, all-ouf principle, whenever possible, as well as proper disinfections, are necessary to eliminate the distribution of pathogens within the farm. Dangerous chemicals and veterinary products must be kept in designated areas. Appropriate nutrition and avoidance of stress will boost the immune system of cattle. On the other hand, genetic selection, based on specific genetic indexes, will increase disease resistance. Moreover, proper manure handling and storage reduces the danger of disease transmission. The aim of specific biosecurity programmes is to confront specific health hazards on farm. Such programmes are developed according to the risk analysis methodology, which comprises risk assessment, risk management and risk communication. Both veterinarians and farmers give priority to problems that are related with farm profitability, public health and animal welfare. Grouping health problems by some of their common characteristics, allows a simultaneous approach, without extra effort. Overall, the lack of professional attitude by farmers, the defective design and development, as well as the inadequate organization of Greek cattle farms, are the main obstacles in implementing biosecurity measures. But, part of the responsibility lies on the veterinary profession as well; lack of training and motivation is the most probable explanation.

Swine artificial insemination: development and biotechnology applications

Traditional artificial insemination has been highly contributed in swine global industry development. However, in order to improve the productivity and the reproductive performance of pig farms, new techniques have been performed. Among them, post cervical or intrauterine insemination, deep intrauterine insemination (DUI), intra-oviductal insemination (ΙΟΙ) by laparotomy or laparoscopy, as well as the biotechnological applications, such as sex sorted semen, frozen semen and sperm mediated genes' transfer, have been investigated concerning their efficiency in pig production development. One of the main targets of the aforementioned techniques is to benefit the potential advantages of the high genetic value boars by using the minimal number of spermatozoa needed to achieve a high fertilization rate following artificial insemination. On the other hand, biotechnology could lead in rapid transfer of high genetic potential in inaccessible areas through frozen semen. Moreover, biotechnology could support pig industry increasing the female pigs' production according to the consumers' choices and animals' welfare by sex sorted semen application, as well as producing of transgenic pigs aiming an increased disease resistance, improvement carcass composition, increased feed intake and growth rate. In vivo studies have evaluated the efficiency of the new developments in insemination technology. The results of these studies demonstrated that a satisfactory conception rate and litter size can be obtained by the insemination of low number of spermatozoa in the appropriate position of the female genital tract at the right time, close to ovulation. High farrowing rate and number of live born piglets were noticed after the post cervical insemination with low number of spermatozoa (lxlO9), compared to the traditional artificial insemination. Similar results were observed in other experiments, where 150xl06 or 3xl05 spermatozoa were inseminated using DUI or ΙΟΙtechnique, respectively. Furthermore, the improvement of the materials of the new artificial insemination procedures (catheters, extenders etc) makes the application of it simpler and easier for the workers after a few training. Although the traditional artificial insemination is an indispensable method for the commercial pig farms, the application of currently available sperm technologies is feasible to be performed in selected animals of pig farms with high quality control and management system. The aspects of the development on swine artificial insemination technology concerning the biotechnological applications of boar sperm are reported in the present study.

Expression of recombinant human lysozyme in bacterial artificial chromosome transgenic mice promotes the growth of Bifidobacterium and inhibits the growth of Salmonella in the intestine

Targeted gene modification is a novel intervention strategy to increase disease resistance more quickly than traditional animal breeding. Human lysozyme, a natural, non-specific immune factor, participates in innate immunity, exerts a wide range of antimicrobial activities against pathogens, and has immuneregulatory effects. Therefore, it is a candidate gene for improved disease resistance in animals. In this study, we successfully generated a transgenic mouse model by microinjecting a modified bacterial artificial chromosome containing a recombinant human lysozyme (rhLZ) gene into the pronuclei of fertilized mouse embryos. rhLZ was expressed in serum, liver, spleen, lung, kidney, stomach, small intestine, and large intestine but not in milk. rhLZ protein concentrations in the serum of transgenic mice ranged from 2.09 to 2.60 mg/l. To examine the effect of rhLZ on intestinal microbiota, total aerobes, total anaerobes, Clostridium, Enterococcus, Streptococcus, Salmonella, Escherichia coli, Staphylococcus, Bifidobacterium, and Lactobacillus were measured in the intestines of transgenic and wild type mice. Results showed that Bifidobacteria were significantly increased (p < 0.001), whereas Salmonella were significantly decreased (p < 0.001) in transgenic mice compared to wild type mice. Our study suggests that rhLZ expression is a potential strategy to increase animal disease resistance.

Effect of polyploidisation on the response of apple (Malus × domestica Borkh.) to Venturia inaequalis infection

Development of new and durable strategies to improve the apple plant’s resistance against apple scab (Venturia inaequalis) remains a major challenge. Polyploids or organisms with three or more complete chromosome sets often possess properties superior to their diploid counterparts. Studies reported that polyploidy confers an increased resistance to biotic and abiotic stress factors. However, the potential use of polyploidy to increase disease resistance is still insufficiently investigated. We determined the influence of artificial genome doubling on the response of three Malus × domestica genotypes, with a variable level of susceptibility to apple scab. Based on visual symptom evaluation and real-time PCR quantification of the V. inaequalis DNA in apple leaves, an increased resistance was observed in the neotetraploid form of the monogenic resistant genotype compared to its diploid progenitor. No pronounced effects were observed comparing ploidy levels of the susceptible genotypes. These results suggest a potential role for polyploidisation in apple scab resistance, but it seems to depend on the degree of disease susceptibility of the genotype. Still, further research on the effects of polyploidy might offer potential in the development of new and durable resistance strategies.

Spatiotemporal expression of MYD88 gene in pigs from birth to adulthood.

MYD88 plays an important role in the immune response against infections. To analyze MYD88 gene expression during different stages of pig development, we used real-time PCR. MYD88 was seen expressed in all tissues examined. MYD88 expression in spleen, lungs, and thymus reached its highest value from 7 to 14 days of age and decreased thereafter. Expression in lymph nodes was high until 28 days of age and then it declined after weaning, with stable low levels in adult pigs. MYD88 expression was high before 35 days of age in the small intestine (duodenum, jejunum, and ileum), where it reached its highest value from 7 to 14 days of age. MYD88 expression in the small intestine declined post-weaning and remained relatively low during adulthood. The results of this study suggest that weaning stress and development of the immune system might be positively correlated with MYD88 expression regulation. Moreover, this study provided evidence that the high expression of MYD88 may diminish weaning stress and increase disease resistance in Meishan pigs.

Worldwide Genetic Diversity of the Wild Species Saccharum spontaneum and Level of Diversity Captured within Sugarcane Breeding Programs

ABSTRACTSugarcane (Saccharum spp.) is grown in tropical and subtropical regions of the world and produces 80% of the world's sucrose primarily for human consumption but is increasingly used as a feedstock for biofuel. Commercial cultivars are hybrids between two species, Saccharum officinarum L. and S. spontaneum L. Saccharum spontaneum is the wild species with generally low sucrose levels and is used to introgress traits such as high yield, increased disease resistance, and ratooning. Molecular markers generated across the Saccharum genome were used to analyze diversity across 430 S. spontaneum accessions collected from 21 different countries and 255 cultivars from two breeding programs. A total of 724 markers were used for principle coordinate and cluster analysis, which revealed two main clusters that corresponded to accessions collected north or south of the Tropic of Cancer. The majority of the accessions clustered according to country of origin. Genetic similarity ranged from 0.25 to 0.54, with the highest diversity in accessions collected in Indonesia, followed by China, India, and Thailand, and the lowest in the Philippines. The diversity in the cultivar collection was lower than in the S. spontaneum accessions, as expected. Despite the low number of S. spontaneum clones used for breeding varieties, 51 to 80% of markers were captured in the breeding populations, although many at a low frequency. This is due to the high heterozygosity of sugarcane related to high ploidy and the introgression programs that have been performed in a number of sugarcane breeding programs. The genetic similarity was highest within the breeding program, and there remains large amounts of unexplored diversity in the wild germplasm. Diversity analysis could be used to guide the selection of wild S. spontaneum accessions, along with phenotypic data for introgression into breeding programs to increase genetic diversity.

Effects of Salinity on Acid Production and Growth of Three Probiotic Microbes with Potential for Application in Intensive Shrimp Aquaculture

Shrimp has been among the top value-added products targeted for production by the aquaculture industry. The increasing demand for shrimp has led to a massive increase in production in several countries across the world. Intensive and super-intensive production systems are facing great challenges handling newly emerging shrimp diseases. The use of antibiotics was one of the first approaches when dealing with such diseases, but the effects of misusing antibiotics and the appearance of antibiotic resistant bacteria are of public concern. As an alternative, probiotics have been applied in aquaculture systems to increase disease resistance, improve feed efficiency, maintain water quality and enhance the growth of aquatic organisms. In this study, the ability of three probiotic microbes to tolerate salinity levels commonly found in intensive shrimp production systems were evaluated. Lactobacillus casei, Saccharomyces cerevisiae and Rhodopseudomonas palustris were cultured in MRS broth, yeast and mold broth, and Van Neil’s broth, respectively, enriched with 1 and 2% NaCl. Microbial survival between treatments were compared as well as the metabolic activity in terms of acidity levels. Additionally, cell morphology was compared using scanning electron microscopy. L. casei and S. cerevisiae showed no significant differences (P>0.05) in media with 1% and 2% NaCl in terms of microbial survival and media acidity levels at 24 h. R. palustris showed a prolonged lag phase extending up to 12 h in 1% and 48 h in 2% NaCl media, and acidity of the media did not vary significantly. Cell morphology of all microbes did not change significantly across all treatments. From these results, it was concluded that L. casei, S. cerevisiae and R. palustris are suitable for application in aquaculture ponds with up to 2% salinity.

Hericium caput-medusae (Bull.:Fr.) Pers. polysaccharide enhance innate immune response, immune-related genes expression and disease resistance against Aeromonas hydrophila in grass carp (Ctenopharyngodon idella)

The objective was to add 0, 400, 800 or 1200 mg/kg of Hericium caput-medusae polysaccharide (HCMP) to the basal diet of grass carp (Ctenopharyngodon idella) and determine effects on humoral innate immunity, expression of immune-related genes and disease resistance. Adding HCMP enhanced (P < 0.05) bactericidal activity at 1, 2 and 3 weeks and also lysozyme activity, complement C3, and SOD activity at 2 and 3 weeks. Supplementing 800 or 1200 mg/kg of HCMP for 2 or 3 weeks increased (P < 0.05) serum concentrations of total protein, albumin and globulin. Two immune-related genes (IL-1β and TNF-α) were up-regulated (P < 0.05) in HCMP supplemented groups given 800 or 1200 mg/kg HCMP after 2 and 3 weeks of feeding. Expression of anti-inflammatory cytokine IL-10 was down-regulated (P < 0.05) after receiving 800 or 1200 mg/kg HCMP for 2 or 3 weeks. Fish fed 800 mg/kg HCMP had maximal disease resistance against Aeromonas hydrophila (65.4%). In conclusion, HCMP enhanced immune response and expression of immune-related genes and increased disease resistance against Aeromonas hydrophila in grass carp, with greatest effects in fish given 800 mg/kg HCMP for 3 weeks.

Over-expression of a grape WRKY transcription factor gene, VlWRKY48, in Arabidopsis thaliana increases disease resistance and drought stress tolerance

Members of the plant WRKY transcription factor family play important roles in regulating response to various biotic and abiotic stresses. A previous gene expression study suggested that the grape gene, WRKY48, was up-regulated during drought stress and fungal infection, as well as in response to exogenous addition of plant hormones. To examine this relationship in more details, we over-expressed VlWRKY48 from V. labrusca × V. vinifera (cv. Kyoho) in Arabidopsis thaliana. Root length and the rate of seed germination were greater in three transgenic lines than that in wild type (WT) plants, the seedlings and adult plants displayed fewer stress-related symptoms following drought treatment than WT, in addition to lower water loss rate. Moreover, over-expression of VlWRKY48 resulted in an increase in the activities of the antioxidant enzymes of catalase, peroxidase and superoxide dismutase after drought treatment, as well as in the expression of several stress-related genes. We also observed that the VlWRKY48 over-expressing lines exhibited higher resistance to powdery mildew, as evidenced by fewer disease symptoms and an increased expression of defense-related genes following infection. Taken together, the results suggest that VlWRKY48 regulates a range of responses to drought stresses, and enhances resistance to powdery mildew infection.

Metabolic pathways and genes identified by RNA-seq analysis of barley near-isogenic lines differing by allelic state of the Black lemma and pericarp (Blp) gene

BackgroundSome plant species have ‘melanin-like’ black seed pigmentation. However, the chemical and genetic nature of this ‘melanin-like’ black pigment have not yet been fully explored due to its complex structure and ability to withstand almost all solvents. Nevertheless, identification of genetic networks participating in trait formation is key to understanding metabolic processes involved in the expression of ‘melanin-like’ black seed pigmentation. The aim of the current study was to identify differentially expressed genes (DEGs) in barley near-isogenic lines (NILs) differing by allelic state of the Blp (black lemma and pericarp) locus.ResultsRNA-seq analysis of six libraries (three replicates for each line) was performed. A total of 957 genome fragments had statistically significant changes in expression levels between lines BLP and BW, with 632 fragments having increased expression levels in line BLP and 325 genome fragments having decreased expression. Among identified DEGs, 191 genes were recognized as participating in known pathways. Among these were metabolic pathways including ‘suberin monomer biosynthesis’, ‘diterpene phytoalexins precursors biosynthesis’, ‘cutin biosynthesis’, ‘cuticular wax biosynthesis’, and ‘phenylpropanoid biosynthesis, initial reactions’. Differential expression was confirmed by real-time PCR analysis of selected genes.ConclusionsMetabolic pathways and genes presumably associated with black lemma and pericarp colour as well as Blp-associated resistance to oxidative stress and pathogens, were revealed. We suggest that the black pigmentation of lemmas and pericarps is related to increased level of phenolic compounds and their oxidation. The effect of functional Blp on the synthesis of ferulic acid and other phenolic compounds can explain the increased antioxidant capacity and biotic and abiotic stress tolerance of black-grained cereals. Their drought tolerance and resistance to diseases affecting the spike may also be related to cuticular wax biosynthesis. In addition, upregulated synthesis of phytoalexins, suberin and universal stress protein (USP) in lemmas and pericarps of the Blp carriers may contribute to their increased disease resistance. Further description of the DEGs haplotypes and study of their association with physiological characteristics may be useful for future application in barley pre-breeding.

Genetic parameters for resistance against Flavobacterium columnare in Nile tilapia Oreochromis niloticus (Linnaeus, 1758).

Columnaris disease is a major cause of mortality in tilapia hatcheries and commonly occurs during the summer season in Thailand. One way of reducing the problem is by selective breeding for increased disease resistance. The objective of this study was to estimate quantitative genetic parameters for resistance against columnaris in the Chitralada 4 strain of Nile tilapia. Data from 43 full-sib families (2,580 records) of fry (age=32±4days post-hatch) were used in the analyses. Initially, fry were subjected to bath challenge with Flavobacterium columnare (LD50 concentration=1.2×106 CFU/ml) for 14 days. Disease resistance was defined as the number of days from challenge until death (DD) or as a binary trait (dead/alive) on day 14. Linear animal and sire-dam models were used for DD, while threshold animal, threshold sire-dam, binary linear animal and binary linear sire-dam models were used for binary outcomes. Covariate effect of age, fixed effect of challenge day and random effects of the individual animals or sires and dams were included in the models. Mean survival was 32.4±11.6%, and survival rates of the best and poorest families were 70% and 8%, respectively. The highest estimate of heritability (0.30±0.025) was obtained under the threshold sire-dam model. Heritability estimates for DD (0.16±0.034 and 0.17±0.046) were comparable to those obtained from the threshold animal (0.15±0.031) and the binary linear (0.14±0.045 and 0.15±0.044) models. The linear animal and sire-dam models for DD and the threshold sire-dam models performed equally with similar values of rEBV (0.629, 0.628 and 0.627) and accuracy of selection (0.793, 0.793 and 0.791). This study reveals the potential of selective breeding to increase disease resistance to F.columnare in the studied population of Nile tilapia.

Selection on resilience improves disease resistance and tolerance to infections1

Response to infection in animals has 2 main mechanisms: resistance (ability to control pathogen burden) and tolerance (ability to maintain performance given the pathogen burden). Selection on disease resistance and tolerance to infections seems a promising avenue to increase productivity of animals in the presence of disease infections, but it is hampered by a lack of records of pathogen burden of infected animals. Selection on resilience (ability to maintain performance regardless of pathogen burden) may, therefore, be an alternative pragmatic approach, because it does not need records of pathogen burden. Therefore, the aim of this study was to assess response to selection in resistance and tolerance when selecting on resilience compared with direct selection on resistance and tolerance. Monte Carlo simulation was used combined with selection index theory to predict responses to selection. Using EBV for resilience in the absence of records for pathogen burden resulted in favorable responses in resistance and tolerance to infections, with higher responses in tolerance than in resistance. If resistance and tolerance were unfavorably correlated, lower selection responses were obtained, especially in resistance. When the genetic correlation was very unfavorable, the selection response in tolerance became negative. Results showed that lower selection responses in resistance and tolerance were obtained when the frequency of disease outbreaks was 10% rather than 50% of the contemporary groups. The efficiency of selection on EBV for resilience compared with selection on EBV for resistance and tolerance was, however, not affected by the frequency of disease outbreaks. When records on pathogen burden were available, selection responses in resistance, tolerance, and the total breeding goal were 3 to 28%, 66 to 398%, and 2 to 11% higher, respectively, than when using the EBV for resilience, showing a clear benefit of recording pathogen burden. This study shows that selection on resilience is a pragmatic way of increasing disease resistance and tolerance to infections in the absence of records on pathogen burden, but recording pathogen burden would yield higher selection responses in resistance and tolerance.

SG2-Type R2R3-MYB Transcription Factor MYB15 Controls Defense-Induced Lignification and Basal Immunity in Arabidopsis.

Lignification of cell wall appositions is a conserved basal defense mechanism in the plant innate immune response. However, the genetic pathway controlling defense-induced lignification remains unknown. Here, we demonstrate the Arabidopsis thaliana SG2-type R2R3-MYB transcription factor MYB15 as a regulator of defense-induced lignification and basal immunity. Loss of MYB15 reduces the content but not the composition of defense-induced lignin, whereas constitutive expression of MYB15 increases lignin content independently of immune activation. Comparative transcriptional and metabolomics analyses implicate MYB15 as necessary for the defense-induced synthesis of guaiacyl lignin and the basal synthesis of the coumarin metabolite scopoletin. MYB15 directly binds to the secondary wall MYB-responsive element consensus sequence, which encompasses the AC elements, to drive lignification. The myb15 and lignin biosynthetic mutants show increased susceptibility to the bacterial pathogen Pseudomonas syringae, consistent with defense-induced lignin having a major role in basal immunity. A scopoletin biosynthetic mutant also shows increased susceptibility independently of immune activation, consistent with a role in preformed defense. Our results support a role for phenylalanine-derived small molecules in preformed and inducible Arabidopsis defense, a role previously dominated by tryptophan-derived small molecules. Understanding the regulatory network linking lignin biosynthesis to plant growth and defense will help lignin engineering efforts to improve the production of biofuels and aromatic industrial products as well as increase disease resistance in energy and agricultural crops.

Winter wheat varieties with group disease resistance for Forest-Steppe of Ukraine

Purpose. To analyze prospective winter wheat varieties for resistance to pathogens of major diseases and to identify resistant ones among them. Methods. The research was conducted according to common techniques in conditions of artificial inoculation with pathogens in field infectious nurseries and laboratory conditions. Assessment of winter wheat plant resistance to pathogens was carried out in dynamics (to study the disease progress), mark during period of maximum disease development was principal. Results During 2016-2017, 143 winter wheat varieties from different breeding institutions of Ukraine were studied on separate artificial infectious backgrounds. It is shown that weather conditions significantly influence on wheat disease progress. There were identified varieties being resistant to individual and group of diseases. Resistance against three diseases was demonstrated with Sotnytsia, Karmen, Kalancha originated from Institute of Plant Physiology and Genetics (IPPG), Zaporuka, Zadumka Odeska (Plant Breeding and Genetics Institute (PBGI)), Vidradna (Bila Tserkva Experimental Breeding Station (BTs EBS)), Zapashnyi, Ovidiy (Рlant Production Institute nd. a. V. Ya. Yuryev (IPP)); resistance against four diseases was demonstrated with Spasivka, Lymarivna, Slavna (IPPG), Natalka (IPPG, the V.M. Remeslo Myronivka Institute of Wheat (MIW), Lastivka, Kniahynia Olga, Krasen, Selianka (PBGI), Lybid (BTs EBS), Olzhana (IPP). For resistance against 5 diseases the varieties Voloshkova (MIW, IPPG), Smuhlianka (IPPG, MIW), Zhuravka Odeska (PBGI) were identified. Conclusions. In order to identify effective sources of resistance against pathogens of major diseases, resistance of winter wheat varieties bred at different breeding centers of Ukraine on separate artificial infectious backgrounds of these pathogens was tested. Depending on the weather conditions, the disease progress level varied. Among the samples studied, the varieties with group resistance against common bunt, root rot, Fusarium head blight, powdery mildew, brown rust, and Septoria leaf blotch in various combinations were found. The sources of resistance identified are recommended as initial material to be used in breeding programs for creation of modern high-yielding bread winter wheat varieties with increased disease resistance.

Efficacy of viable Bacillus pumilus isolated from farmed fish on immune responses and increased disease resistance in Nile tilapia (Oreochromis niloticus): Laboratory and on-farm trials

Applications of viable Bacillus pumilus AQAHBS01 isolated from Nile tilapia farms as probiotics were studied in both laboratory and farm conditions. In the laboratory, feeding fish (approximately 50 g) with feed containing viable B. pumilus at concentrations of 1 × 107-109 colony forming units (CFU)/kg elevated fish immune responses, as indicated by their phagocytic activity and superoxide anion levels, and led to more effective disease resistance against Streptococcus agalactiae. However, when these concentrations were applied to Nile tilapia cultures growing in cage culture systems, only B. pumilus AQAHBS01 at concentrations of 1 × 108 and 109 CFU/kg diet could effectively enhance disease resistance against S. agalactiae during the critical period of early to middle April when the temperature reached 33 °C, whereas control fish and fish that consumed B. pumilus AQAHBS01 at concentrations of 1 × 107 CFU/kg showed very rapid streptococcosis-induced mortality. However, in late April, massive levels of organic matter-containing water flowed into the culture areas, causing all fish groups to become infected with Flavobacterium columnare. Moreover, the dissolved oxygen levels in the river declined to critical levels of approximately 1.0–1.5 mg/L, causing anorectic effects in fish for long periods of time. This effect may have also gradually killed the cultured fish until the end of the experiment. This information strongly demonstrates the effective application of B. pumilus as a probiotic for streptococcosis resistance in both laboratory and field culture conditions. For on-farm cage culture practices, however, fluctuations in water quality remain a significant constraint for probiotic application, as they usually induce negative effects on fish health. This decline in health makes fish more fragile and more susceptible to problems from both infectious and non-infectious diseases, which farmers must consider carefully.

Temporal changes in cutaneous bacterial communities of terrestrial- and aquatic-phase newts (Amphibia).

Animal-associated bacterial communities play essential roles for their host's ecology, physiology and health. Temporal dynamics of these communities are poorly understood, but might be of high relevance for amphibians with a well-expressed biphasic biology of adults where the structure of their skin changes drastically between the aquatic and terrestrial phases. Here, we investigated the temporal dynamics of cutaneous bacterial communities of Lissotriton boscai and Triturus marmoratus by monthly sampling populations from a pond and surrounding terrestrial habitats near A Coruña, Spain. These communities were characterized by 16S rRNA gene amplicons from DNA isolated from skin swabs. Newt bacterial communities displayed variation at three levels: between larvae and aquatic adults, between adult life phases (terrestrial versus aquatic), and temporally within life phases. The skin bacterial communities tended to differ to a lesser extent temporally and between larvae and adults, and more strongly between life phases. Larvae had a higher proportion of reads associated with antifungal taxa compared with adults, while no differences were found among adult life phases. Terrestrial specimens exhibited the highest community diversity. The regular transitions of adult newts between aquatic and terrestrial environments might contribute to the diversity of their skin microbiota and could increase disease resistance.

Biotechnological Advancements for Improving Floral Attributes in Ornamental Plants.

Developing new ornamental cultivars with improved floral attributes is a major goal in floriculture. Biotechnological approach together with classical breeding methods has been used to modify floral color, appearance as well as for increasing disease resistance. Transgenic strategies possess immense potential to produce novel flower phenotypes that are not found in nature. Adoption of Genetic engineering has supported the idea of floral trait modification. Ornamental plant attributes like floral color, fragrance, disease resistance, and vase life can be improved by means of genetic manipulation. Therefore, we witness transgenic plant varieties of high aesthetic and commercial value. This review focuses on biotechnological advancements in manipulating key floral traits that contribute in development of diverse ornamental plant lines. Data clearly reveals that regulation of biosynthetic pathways related to characteristics like pigment production, flower morphology and fragrance is both possible and predictable. In spite of their great significance, small number of genetically engineered varieties of ornamental plants has been field tested. Today, novel flower colors production is regarded as chief commercial benefit obtained from transgenic plants. But certain other floral traits are much more important and have high commercial potential. Other than achievements such as novel architecture, modified flower color, etc., very few reports are available regarding successful transformation of other valuable horticultural characteristics. Our review also summarized biotechnological efforts related to enhancement of fragrance and induction of early flowering along with changes in floral anatomy and morphology.

Effects of dietary Yucca meal on growth, haematology, non-specific immune responses and disease resistance of juvenile Nile tilapia, Oreochromis niloticus (Linnaeus, 1758)

A 10-week feeding trial was conducted to determine the effects of dietary yucca meal supplementation on growth, haematology, non-specific immune responses and disease resistance in juvenile Nile tilapia, Oreochromis niloticus. Six isonitrogenous and isoenergetic experimental diets were formulated to contain 0% (YMS0), 0.1% (YMS0.1), 0.3% (YMS0.3), 0.5% (YMS0.5), 1% (YMS1.0) and 2% (YMS2.0) dietary yucca meal on the dry weight basis. Results of this study showed a higher growth performance for YMS0.1 group with significant differences with YMS0.5, YMS1.0 and YMS2.0 groups. In addition, whole-body protein content of fish fed the YMS0.1 diet was significantly higher as compared to YMS0. Plasma lysozyme activity significantly increased in YMS0.1 group comparing to YMS0 and YMS0.5 groups. Respiratory burst activity of phagocytic blood cells was significantly enhanced when fish were fed the YMS0.1 diet. Results also showed that yucca meal supplementation had moderate effects on glutamic oxaloacetic transaminase and cholesterol levels. After the 14-day challenge test with Aeromonas hydrophila, cumulative survival of fish fed YMS0.1 diet was significantly higher than that of fish fed diet YMS0, YMS1.0 and YMS2.0. These results suggest that the optimum dietary yucca meal inclusion level in the diet of juvenile Nile tilapia could be between 0.1% and 0.14% (23.9~33.4 mg kg−1 saponin) as a feed additive to promote growth, enhance the non-specific immune responses and increase disease resistance.

Assessment and Potential Application of the Probiotic Strain, Bacillus amyloliquefaciens JFP2, Isolated from Fermented Seafood-Jeotgal in Flounder Paralichthys olivaceus Juveniles

The strain Bacillus amyloliquefaciens JFP2 was isolated from Jeotgal, traditional fermented seafood from Jeju Island, South Korea to assess its probiotic and antibacterial effect against fish pathogens. The isolate JFP2 was identified using scanning electron microscopic analysis and 16S rRNA gene sequence analysis. The isolated strain, B. amyloliquefaciens JFP2 showed a broad spectrum of antibacterial activity against both Gram-positive and Gram-negative fish pathogenic bacteria namely Aeromonas hydrophila, Edwardsiella tarda, Photobacterium damselase sup-sps, Photobacterium phosphoreum, Streptococcous parauberis, S. iniae and Vibrio anguillaram. The bacteriocin JFP2 with a molecular mass of 37 kDa that was purified by ammonium sulphate precipitation followed by carboxymethyl-Sephadex column chromatography, showed antibacterial activity at a range of temperatures, from 4º-45ºC and at a range of pH values from 2-12. However, loss of antibacterial activity was observed after treating the bacteriocin with proteolytic enzymes such as pepsin, proteinase K, and trypsin. The mode of antibacterial action shown by the bacteriocin JFP2 was bacteriolytic in nature, resulting in cell wall degradation of A. hydrophila. Dietary inclusion of the isolated JFP2 strain showed improved growth performance in juvenile flounder along with increased disease resistance against Streptococcus iniae. These results indicate that the bacteriocin JFP2 belongs to class IIIa bacteriocin that could be used as a potential alternative antibacterial agent to control pathogenic diseases in aquaculture and seafood industries.