Mariculture development in Kenya: alternatives to siting ponds in the mangrove ecosystem

Pond culture of brackishwater prawns and shrimps has recently generated much interest in Kenya. The mangrove areas are the target zones for the construction of these ponds. With the increasing awareness of the unique ecological role played by the mangroves, there is an urgent need to stop the conversion of mangrove swamps into aquaculture ponds. To develop pond aquaculture without destroying the mangroves, a shift from tide-fed to pump-fed pond systems is recommended in order to divert the farming from the mangroves to higher grounds. Mangrove-friendly mariculture practices like pen, cage and raft culture are discussed. Methods of efficiently utilising the already destroyed mangrove areas are considered.     

Proteomic profiling of integral membrane proteins associated to pathogenicity in Vibrio parahaemolyticus strains

Vibrio parahaemolyticus has been recognized as the causal agent of early mortality syndrome and is currently considered an emerging shrimp disease causing losses of millions in the aquaculture industry. Integral membrane proteins are widely recognized as pathogenicity factors involved in essential mechanisms for V. parahaemolyticus infection, which makes them attractive as therapeutic targets. However, their physico‐chemical properties and weak expression has resulted in under‐representation of these proteins in conventional bottom‐up proteomics, making integral membrane proteomics a challenging task. Integral membrane proteins from a bacterial strain isolated from the hepatopancreases of white shrimp with early mortality syndrome and identified by 16S rRNA sequencing as V. parahaemolyticus and an ATCC strain that is pathogenic for humans were obtained by a sequential extraction method and subjected to relative quantification and identification by isobaric Tags for Relative and Absolute Quantitation. A homology database search resulted in identification of more than two hundred proteins, 35 of which are recognized as pathogenic factors showed statistically significant differential accumulation between the strains. These proteins are mainly associated with adherence, secretion systems, cell division, transport, lysogenization, movement and virulence. Identification of pathogenicity‐related proteins in V. parahaemolyticus provides valuable information for developing strategies based on molecular mechanisms that inhibit these proteins, which may be useful therapeutic targets for assisting the shrimp and aquaculture industry.     

Ontogeny of low molecular weight stress protein p26 during early development of the brine shrimp, Artemia franciscana

Embryogenesis in the brine shrimp, Artemia sp., occurs by one of two pathways: (i) the direct, uninterrupted development of nauplius larvae within the female or (ii) the production of embryos that arrest development at the gastrula stage and enter diapause. Diapause embryos are released from females into the aqueous environment where they remain in diapause until activated by appropriate environmental cues and resume development. These encysted embryos possess at least one low molecular weight stress protein, which we refer to as p26 and which has been implicated previously in the stress response of activated embryos. We investigated the appearance of p26 in developing diapause embryos in utero and looked for its presence in embryos developing directly into nauplii. We found p26 to be specific to diapause-destined embryos; it was not detected in direct-developing embryos. We conclude that p26 is not required for the basic developmental program that produces the nauplius. In diapause-destined embryos, p26 was first detectable after 3 days of development, at which time the embryos were late gastrulae. This protein continues to increase in amount until the encysted embryos are released, approximately 5 days after fertilization. At the time of release almost all p26 is located in the low speed supernatant fraction, but as released embryos continue diapause, p26 transfers to the pelleted nuclear fraction in increasing amounts. Our working hypothesis views p26 as a molecular chaperone preventing protein denaturation and aggregation under conditions associated with metabolic arrest and other stressful states, which these encysted embryos encounter.     

海水池塘中国对虾与罗非鱼施肥混养的实验研究

利用 8个海水池塘陆基围隔 ,进行了封闭式施肥混养中国对虾与罗非鱼的实验研究 .结果表明 ,在对虾放养密度为 0 .92～ 2 .36尾·m- 2 的条件下 ,对虾成活率为 75.72～89.98% ,平均为 82 .40 % .产量在 1 1 .4～ 2 4 .1 g·m- 2 之间 (养殖期为 91d) .生产力为0 .2 39g·m- 2 .d- 1 .在罗非鱼放养量为 0 .2 4尾·m- 2 (体重 1 0 0 g左右 )的条件下 ,鱼虾的数量最适配比为 1 :1 0 ,中国对虾 (体长 3.0 0cm左右 )的最适放养量约为 2 .40尾·m- 2 .     

对虾病毒病病毒和细菌合并感染的病理特点和诊断价值

应用电镜超薄切片及光学石蜡切片和环氧树脂薄片技术,观察健康对照组、疾病始发组和濒临死亡组的草虾、中国对虾、日本对虾和长毛对虾的肝胰腺和中肠,结果在３组４种对虾中均检测到病毒,只在濒临死亡组的４种对虾中发现病毒与细菌的合并感染。合并感染的病毒有ＭＢＶ、球形病毒和淋巴样细胞核型杆状病毒。细菌以弧菌为主,其病理变化表现为器官和组织的保护层受损、溶解样坏死和凝固样坏死。仅以病毒和细菌合并感染作为养殖对虾病毒病早期诊断的指标是不够的,仅可作为辅助性诊断指标。但合并感染对评估对虾病毒病的预后以指导捕捞,却有一定意义。     

Isolation and substrate specificities of five chitinases from the hepatopancreas of Northern shrimp, Pandalus borealis

Five enzymes designated chitinase I, IIa, IIb, III, and IV have been isolated from the hepatopancreas of Pandalus borealis in a procedure including column chromatography on Q-Sepharose, Sephacryl S-200, phenyl-Superose and Superdex 75. The isolated enzymes were analysed by SDS PAGE. Chitinase I, III, and IV gave only one major band corresponding to 54–55 kDA. Chitinase IIa showed one major band at 61 kDA and two diminutive bands at 17 and 55 kDa, while chitinase IIb gave two major bands at 17 and 44 kDa. Estimated by gel filtration, the native molecular weights of chitinase I, IIa, IIb, III, and IV were 61, 69, 39, 57, and 54 kDa, respectively. The substrate and reaction specificities of the isolated chitinases were investigated, and the results show that the isolated enzymes are true chitinases. They do not hydrolyse N,N′-diacetylchitobiose or p-Nitrophenyl-N-acetyl-β-D-glucosaminide, but express activities when longer chitooligosaccharides or nitrophenylated chitooligosaccharides are used as substrates. Chitinase I and IIa gave an initial random cleavage pattern and might be classified as endochitinases, while chitinase III and IV released dimeric units from the substrates and might be termed chitobiosidases.     

Consumption of deep-sea shrimp by bigeye flounder Hippoglossina macrops in fishing grounds off northern Chile

Feeding of the bigeye flounder Hippoglossina macrops on the shrimp Heterocarpus reedi was analysed between 20 November and 4 December 1995. Feeding on H. reedi intensified between 0900 and 1600 hours with a second, smaller peak between 2300 and 0200 hours. Assuming an exponential gastric evacuation model, the gastric evacuation rate was estimated as 0·197 % W h ⁻¹ (95% CI=0·025–0·369). The daily ration decreased latitudinally from north to south from 3·62 to 2·66 and from 2·06 to 0·41 %W , respectively. Consumption was related positively to shrimp biomass and influenced by flounder size structure in the three fishing zones analysed and was estimated as 0·08–0·02% of the total shrimp biomass.     

Three Sesquiterpenoid Dimers from Chloranthus japonicus: Absolute Configuration of Chlorahololide A and Related Compounds

A novel sesquiterpenoid dimer, named multistalide C ( 1 ), together with two known congeners, shizukaols C ( 2 ) and D ( 3 ), was isolated from the whole plant of Chloranthus japonicus Sieb. The structures of compounds 1 , 2 , 3 were elucidated by extensive HR‐ESI‐MS, 1D, and 2D NMR spectroscopic analysis. Compounds 1 , 2 , 3 exhibited significant toxic effects on brine shrimp larvae (Artemia salina). The absolute configuration of 1 was established by CD/TDDFT calculations. The related compound chlorahololide A was also reinvestigated. The previous assignment of the absolute configuration of chlorahololide A and several related sesquiterpenoid dimers, based on an incorrect application of the exciton chirality method, is criticized. Chirality 28:158–163, 2015. © 2015 Wiley Periodicals, Inc.     

Bioconversion of AHX to AOH by resting cells of Burkholderia contaminans CH-1

Fairy rings are zones of stimulated grass growth owing to the interaction between a fungus and a plant. We previously reported the discovery of two novel plant-growth regulating compounds related to forming fairy rings, 2-azahypoxanthine (AHX) and 2-aza-8-oxohypoxanthine (AOH). In this study, a bacterial strain CH-1 was isolated from an airborne-contaminated nutrient medium containing AHX. The strain converted AHX to AOH and identified as Burkholderia contaminans based on the gene sequence of its 16S rDNA. The quantitative production of AOH by resting cells of the strain was achieved. Among seven Burkholderia species, two bacteria and two yeasts tested, B. contaminans CH-1 showed the highest rate of conversion of AHX to AOH. By batch system, up to 10.6 mmol AHX was converted to AOH using the resting cells. The yield of this process reached at 91%.     

Fusariosis in the shrimp Penaeus semisulcatus cultured in Israel

The first case of a mycotic infection in shrimp in Israel is reported. Fusarium solani produced a large melanized lesion in a specimen of Penaeus semisulcatus cultured at Eilat, on the Red Sea. Fungal hyphae elicited a strong hemocytic response in cuticular and connective tissues. In the underlying muscle, the inflammatory reaction appeared weaker, suggesting a gradual failure by the host to resist mycelial invasion. Three cases of human keratomycosis by F. solani have been reported in recent years in Israel, suggesting that handling infected shrimp may represent a hazard to aquaculturists.