Integrated Rice-Based Shrimp and Crabs Farming: Adaptation to Climate Change and Potential Mitigation of Global Warming in the Coastal Wetlands of Bangladesh

Coastal agriculture is vulnerable to climate change, thereby may affect food production systems and food security in Bangladesh. Methane (CH4) emission from coastal wetlands rice farming is a major environmental concern due to its global warming potential. Therefore, field experiments were conducted at the southern coastal region of Shyamnagar, Satkhira, to investigate the feasibility of Rice-Shrimp and Rice-Crabs mixed farming for adaptation to the changing climate and sustaining food production system. The experimental treatments were designed on rice-based diversified farming systems such as rice sole cropping with no NPKS + no soil amendments (T1), rice sole cropping following farmers’ practice (FP) without soil amendment (T2), rice sole cropping following FP with phosphogypsum (PG) amendment (T3), Rice-Shrimp mixed culture with PG amendment (T4), Rice-Crabs mixed culture with PG amendment (T5), Rice-Shrimp mixed culture + PG amendment with Spirulina (Cyanobacteria) inoculation (T6), and Rice-Crabs mixed culture + PG amendment with Spirulina inoculation (T7). A closed chamber technique was followed to collect gas samples from the rice paddy field and samples were analyzed by Gas Chromatograph. It was found that Rice-Shrimp (T6) and Rice-Crabs mixed farming (T7) practices significantly decreased GWPs compared to the rice sole cropping system. In the dry boro season, the maximum GWPs 4175 kg CO2 eq. ha-1 was recorded from rice sole cropping (T2), which was decreased by 30% and 36.7% under Rice-Shrimp (T6) and Rice-Crabs (T7) mixed farming practices, respectively. Furthermore, in the wet aman season, maximum GWP 4525 kg CO2 eq. ha-1 was recorded from rice sole cropping (T2), which was decreased by 33.0% and 38.8% under Rice-Shrimp and Rice-Crabs mixed farming, respectively. Rice grain yield was low under rice sole cropping (3500 kg/ha), which was increased by 11.0% and 14.7% under Rice-Shrimp mixed farming amended with PG and Spirulina (T6) during wet aman and dry boro seasons, respectively. The postharvest soil properties, such as soil organic matter content, redox potential value (Eh), and exchangeable K+ and Ca2+, contents in soil increased significantly with Phosphogypsum and Spirulina applications, however, decreased Na+ content and electrical conductivity (EC) eventually improved rice plants’ tolerance to salinity and enhanced overall productivity of Rice-Shrimp and Rice-Crabs mixed farming. Conclusively, the conversion of wetland mono rice cropping into mixed Rice-Shrimp and Rice-Crabs farming would be a feasible strategy to sustain rice aquaculture-based farming, ensure food security and mitigate GWPs in coastal wetlands ecosystem.

拟南芥心皮发育CRABS CLAW基因的克隆与荠菜遗传转化

CRABS CLAW(CRC)是控制拟南芥心皮发育的主要基因之一,属MADS box基因家族中的成员.根据GenBank收录的CRABS CLAW基因的cDNA序列设计引物,通过RT-PCR的方法,从哥伦比亚型拟南芥总RNA中扩增出CRABS CLAW基因的全长cDNA片段,将其克隆到pMD18-T载体中,经测序证明该片段与GenBank报道的序列完全一致.以Ti质粒载体pWM101为基础,构建了由组成型启动子CaMV35S调控的CRC基因的植物表达载体pWM101-CRC,通过根癌农杆菌花序浸渍法转化荠菜,获得了转CRC基因的荠菜植株.CRC基因在荠菜中的组成型表达对荠菜心皮形态和大小都产生了一定影响.

Flow cytometric analysis of DNA content for four commercially important crabs in China

The genome size（C-value） of an organism is referring to the DNA content of its non-replicated haploid chromosome complement,generally deduced from measuring somatic diploid nuclei.We presented genome size（C-value） data obtained by flow cytometry for four commercially important crabs（Portunus trituberculatus,Charybdis japonica,Scylla paramamosain,and Eriocheir sinensis） common in the coast of China.Gallus domesticus（2C=2.5 pg） was used as the internal standard.The results showed that the C-value for P.trituberculatus,C.japonica,S.paramamosain,and E.sinensis were（2.31±0.01） pg,（2.33±0.03） pg,（1.64±0.02） pg,and（2.29±0.03） pg,respectively.The C-value of P.trituberculatus,C.japonica and S.paramamosain were reported for the first time.The data represented by the four species indicated that they had lower DNA contents than average DNA values in crustaceans（（4.99±0.48） pg）,and three of the four values were very similar if not identical.The results provide useful data for future studies in the fields of biodiversity,species conservation,and phylogeny of these commercial crabs.They will also be helpful in instructing the hybridization breeding program and estimating the cost of the whole genome sequencing project.

Life Stage, Gender and Movement of Blue Crabs (Callinectes sapidus) in Lake Mattamuskeet and Connecting Canals

In their ranges on east and south coasts of the Americas as well as their established invasions in the Adriatic and Baltic,blue crabs,Callinectes sapidus,inhabit estuaries,sounds and coastal oceans and are commercially and ecologically important.How crabs move in response to physical variables is important to management.We monitored life stages at canal control structures,assessed gender ratios with recreational crabbing,learned from crabbers,and studied movements of tagged crabs in a canal connecting Lake Mattamuskeet to the Pamlico sound.Juveniles enter the lake through two of 4 canals connecting to the sounds.Females migrate out through one canal.The lake standing population is about 70% male.Movements of 240 crabs in August 2012 and 102 crabs in October 2014 were quantified using RFID tags with co-located meteorological and oceanographic devices.Non-spawning females and males are nomadic.Crabs released in the canal move in response to changes in water depth and go with the flow,toward the Pamlico Sound(summer 76% and fall 78%).What crabbers describe as a fall migration appears to be concentration of crabs in warmer deeper canals and then southern movement with flow generated by strong north winds.To be effective,management strategies like migratory corridors require understanding of crab movements.

Implementing geostatistical analysis to study spatio-temporal distribution patterns of swimming crabs(Portunus trituberculatus)

This study attempted to compare the performance of local polynomial interpolation,inverse distance weighted interpolation,and ordinary kriging in studying distribution patterns of swimming crabs.Cross-validation was used to select the optimum method to get distribution results,and kriging was used for making spatial variability analysis.Data were collected from 87 sampling stations in November of 2015(autumn)and February(winter),May(spring)and August(summer)of 2016.Results indicate that swimming crabs widely distributed in autumn and summer:in the summer,they were more spatially independent,and resources in each sampling station varied a lot;in the winter and spring,the abundance of crabs was much lower,but the individual crab size was bigger,and they showed the patchy and more concentrative distribution pattern,which means they were more spatially dependent.Distribution patterns were in accordance with ecological migration features of swimming crabs,which were affected by the changing marine environment.This study could infer that it is applicable to study crab fishery or even other crustacean species using geostatistical analysis.It not only helps practitioners have a better understanding of how swimming crabs migrate from season to season,but also assists researchers in carrying out a more comprehensive assessment of the fishery.Therefore,it may facilitate advancing the implementation in the pilot quota management program of swimming crabs in northern Zhejiang fishing grounds.

Cloning of CRABS CLAW Gene from Brassica napus and Construction of Its RNA Interference Expression Vector

CRABS ClAW （CRC） is a member of the YABBYA transcription factor gene family that plays an important role in floral organ development of plants. This study aimed to further investigate the regulatory function of CRC transcription factor in the development of floral organs of rape （Brassica napus L. ）. A 580 bp fragment of CRC gene was cloned by RT-PCR from total RNA of buds of rape cultivar Ningyou No. 10 to construct an inverted repeated expression cassette of CRC gene using intermediate vector pHturieane. Firstly, CRC gene fragment was positively inserted into the 5＇ end of a spliceable intron and negatively inserted into the 3＇ end of the intron. Subsequently, CaMV35S promoter sequence and inverted repeated expression cassette of CRC gene were transferred into pUC18 multiple clone site of binary expression vector pCAMBIAI1390. The constructed interference expression vector was named pA6-CRCi, which was further confirmed by restriction enzyme digestion and sequencing.

Using Sr isotopes to trace the geographic origins of Chinese mitten crabs

Identifying the geographic origins of Chinese mitten crabs is important for food safety and fair market competition.In this study,we used strontium(Sr) isotopes as a tool to trace the geographic origins of Chinese mitten crabs.Chinese mitten crabs,water,and different types of crab feed were collected from four different lakes for Sr isotope analyses.The results showed that the Sr isotope compositions of the different parts from one single crab were consistent within error,indicating that any piece of a crab could be used to represent the Sr isotope characteristics of the whole crab.The Sr isotope compositions of Chinese mitten crabs from the same lake were consistent within the analytical error,and the values were similar to the Sr isotope composition of the water from the same lake.However,the Sr isotope compositions of water and crabs from different lakes are significantly different.Therefore,the Sr isotope compositions of Chinese mitten crabs are mainly controlled by lake water composition,while the impact of feed is limited.This study provides an effective method for tracing the geographic origins of Chinese mitten crabs.

Mitochondrial Genome of Episesarma lafondii(Brachyura:Sesarmidae)and Comparison with Other Sesarmid Crabs

Complete mitochondrial genomes(mitogenomes)can provide useful information for phylogenetic relationships,gene rearrangement,and molecular evolution.Here,the complete mitogenome of Episesarma lafondii(Brachyura:Grapsoidea:Sesarmidae)was sequenced through next-generation sequencing technique for the first time.The 15640 bp mitogenome contains the entire set of 37 genes and an AT-rich region.The rearrangements of two tRNA genes(tRNA-His and tRNA-Gln)are compared with that in the pancrustacean ground pattern,and the tandem duplication/random loss model was selected to explain the observed gene rearrangements.The phylogenetic results showed that all sesarmid crabs belong to the same group,wherein the genus Episesarma showed the closest relationship with Clistocoeloma.Furthermore,the monophyly of each family was well supported except for Xanthidae,Gecarcinidae,and Homolidae.The correlation between the phylogeny of Sesarmidae species and the gaps in the QIM region was analyzed.Evidently,the gaps between Q and I(Gap3 and between I and M(Gap4)degenerated with the evolution process.In general,the results will contribute to the in-depth understanding of gene rearrangements in Sesarmidae mitogenomes and provide new insights into the phylogeny of Brachyura.

High Microplastic Contamination in Juvenile Tri-Spine Horseshoe Crabs:A Baseline Study of Nursery Habitats in Northern Beibu Gulf,China

Microplastics(MPs)are ubiquitous in marine sedimentary environments.Their occurrence in horseshoe crabs and interactions with the sedimentary environment has not been determined.In this study,MPs,mostly microfibers,were found in all extracted gastrointestinal tract(GIT)samples of the juvenile Tachypleus tridentatus from the northern Beibu Gulf,China.The MP concentrations(4–53 items ind-1)were higher than those in most marine benthic invertebrates(<15 items ind-1)reported in Chinese waters,despite their generally low level in habitat sediments(9–1818 items kg-1).The correlation between the juveniles and sediments was not evident,but the abundance in juvenile horseshoe crab GITs decreased with ages.The findings were relevant to the life-history characteristics of the species,typically with limited dispersal capability and their spending nine years or longer time living in mangrove wetlands during low tides,with apparent ontogenetic changes in their diets.These baseline data enable a better understanding of MP availability in benthic macroinvertebrates,and the ecological risks present in the ecosystems.

Genetic Differences of Mitten Crabs Based on RFLP Analysis on Mitochondrial Cytochrome Oxidase Subunit I(COI) Gene

The genetic differences of 15 mitten crab populations from 6 river systems in China's Mainland and 1 population from Russia were studied based on RFLP analysis of mitochondrial cytochrome oxidase subunit I （CO I）. The results showed that Tas I-RFLP pattern could be used as a genetic marker to distinguish Eriocheir hepuensis from Eriocheir sinensis, Eriocheirjaponica and Eriocheir leptognathus; genetic distances among 13 populations of Eriocheir sinensis range from 0 to 0.015, indicating that they were different geographic strains; the subspecies status of Eriocheir sinensis and Eriocheir hepuensis （population from Nanliujiang） were considered owning to their genetic distances of 0.02-0.044, indicating that genetic divergence between them was low; Eriocheir leptognathus （population from Nanpaihe, Tianjin） was the most distant taxon with genetic distances value of 0.147-0.195, which could be defined as genetic distances between species in genus Eriocheir.

Mitochondrial Haplotypes suggest Genetic Component for Habitat Preference in Blue Crabs

Atlantic blue crabs(Callinectes sapidus)are ecologically and commercially fundamental.Life stages are punctuated with migration.Adults and juveniles live in estuaries and sounds.Larval stages develop in the coastal ocean.Juvenile and adult crabs occupy habitats from high salinities to fresh water.We determined whether maturing juvenile and adult blue crab habitat use is reflected in mitochondrial cytochrome oxidase 1 haplotypes.High salinity crabs had lower haplotype diversity(0.7260±.03900)compared to spawning crabs(0.9841±.00021)and low salinity crabs(0.94154±.00118).Significant pairwise differences in haplotypes were found between high salinity and spawning crabs(Nm=0.26018,p<0.001),and between high salinity and low salinity crabs(Nm=0.19482,p<0.001)indicating a lack of gene flow.Crabs from high salinity had highly significant genetic differentiation compared to spawning crabs(Fst=0.11830,p<0.001)and low salinity crabs(Fst=0.09689,p<0.001).Results support the hypothesis that genetics influence habitat selection.Crab larvae mix in the coastal ocean but occupy specific habitats upon return to sounds and estuaries.These findings have implications for the management of fisheries.

Size specific boldness associated with differences in resource requirements and habitat use: a cross-sectional study in hermit crabs

Animal personality is often studied within compressed periods of observation that represent narrow windows in comparison to animal lifespans.Although much is known about the relations between repeatable personality traits and cross-situational behavioral plasticity,less is known about how such traits might differ across age classes or life history transitions.We conducted a cross-sectional study of startle response duration in 3 size classes of Pagurus bernhardus,the common European hermit crab.We defined size classes using transitions in the preferred species of gastropod shells that accompany growth,and this change in preference is in turn associated with a transition from intertidal to subtidal habitats.Compared with small-and medium-sized intertidal individuals the larger subtidal hermit crabs behaved cautiously by showing startle responses of greater duration following disturbance.Startle responses were also repeatable within all 3 size classes,confirming the presence of animal personality in intertidal hermit crabs and demonstrating that this pattern is retained within the largest size classes,which have undergone the transition from intertidal to subtidal habitat.Interestingly,there was a trend for the pattern of repeatable startle response durations to increase with size class,with the highest value for repeatability and the greatest range of startle response durations being present within the large subtidal population.The greater range of startle responses indicates that the longer startle response durations in some larger individuals are more likely due to developmental changes with age and habitat use than reflecting selection against the boldest individuals during earlier stages of life.

Crab脉冲星巨脉冲辐射等待时间分布的非稳态泊松模拟

利用中国科学院新疆天文台南山观测站26m射电望远镜,在中心频率1556MHz,对Crab脉冲星(PSR B0531+21)进行了长达12.6h的连续观测,观测带宽为512MHz,时间分辨率为32μs,研究了巨脉冲辐射的等待时间分布特征.观测共探测到2097个信噪比大于10的巨脉冲,对应的流量密度大于100Jy.巨脉冲的爆发率表现为高度的间歇性,在较短的时间内具有较高的爆发率,在相对长的宁静期内巨脉冲的爆发率较低,尤其是中间脉冲相位内的巨脉冲爆发.相邻两个巨脉冲的等待时间分布表现为幂律分布特征,可以用一个非稳态的泊松过程进行模拟,这表明巨脉冲的爆发是一种独立的随机事件.此外,主脉冲和中间脉冲相位上的巨脉冲具有不同的等待时间分布特征,这意味着脉冲星不同磁极的巨脉冲辐射机制可能是不同的.这些观测结果对于理解脉冲星的射电辐射机制具有重要意义.

多发性骨髓瘤CRAB症状与抗氧化酶活性的相关性分析

目的:探讨多发性骨髓瘤(MM)患者CRAB症状的常见临床指标与抗氧化酶活性之间的联系。方法:比色法检测44名骨髓瘤患者及12名非恶性血液病患者骨髓上清中的过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GPX)和超氧化物歧化酶(SOD)的活性,分析两组抗氧化酶的活性差异以及骨髓瘤组中抗氧化酶的活性与血钙、血肌酐(Scr)、血红蛋白(Hb)、碱性磷酸酶(ALP)及骨破坏区域数量的关系。结果:与对照组相比,骨髓瘤患者的抗氧化酶活性更低(P<0.05)。当血钙、ALP的浓度高于正常水平,Hb低于85 g/L及存在多个骨破坏区域时,抗氧化酶CAT、SOD和GPX的活性明显降低(P<0.05);当Scr高于正常水平时,GPX活性明显降低(P<0.05)。回归分析结果显示,CAT、SOD、GPX与血钙(r=-0.538,r=-0.456,r=-0.431)、Scr(r=-0.342,r=-0.384,r=-0.463)和ALP(r=-0.551,r=-0.572,r=-0.482)均呈负性相关。结论:抗氧化酶CAT、SOD和GPX的活性在多发性骨髓瘤患者中下降,并且与CRAB症状的常见临床指标(血钙、Scr、ALP)呈负性相关,或许可以通过提高骨髓瘤患者体内的抗氧化酶活性来治疗CRAB症状。

Evolutionary relationship of three mitten crabs(Eriocheir sp)revealed by mitogenome and 5S ribosomal DNA analysis

To reveal the evolutionary relationship of three mitten crabs(Eriocheir sinensis,E.hepuensis,and E.japonica),complete mitogenomes and nuclear 5S rDNA sequences were analyzed.Sequencing revealed that the mitogenomes analyzed shared conserved organization of the coding and non-coding regions but genetic variation was identified.Among the three mitten crabs distinct tandem repeats were identified in the mitochondrial D-loop region.The 5S gene(5S rDNA)sequence was highly conserved across the three species,whereas non-transcribed spacer(NTS)region exhibit high levels of variation including insertions,deletions and point mutations.Cluster analysis suggested that the three mitten crabs had their own independent 5S rDNA sequence variation and evolutionary pattern.Both mitogenome and 5S rDNA sequence analysis revealed significant genetic variation across the mitten crabs species.Phylogenetic analysis using mitogenome and 5S rDNA sequences demonstrated that E.japonica was relatively more distant from E.sinensis and E.hepuensis.This study extended our previous knowledge and confirmed that the three mitten crabs are likely to be genetically differentiated species.In addition,our study also provided insights into the conservation of pure natural resources of E.sinensis,an important aquaculture species.

Seasonal response of nitrogen exchange fluxes to crab disturbance at sediment-water interface in coastal tidal wetlands

Coastal wetlands are hotspots for nitrogen(N)cycling,and crab burrowing is known to transform N in intertidal marsh soils.However,the underlying mechanisms remain unclear.This study conducted field experiments and used indoor control test devices to investigate the seasonal response of nitrogen to crab disturbance at the sediment-water interface in coastal tidal flat wetlands.The results showed that crab disturbance exhibited significant seasonality with large seasonal differences in cave density and depth.Due to crab disturbance,nitrogen fuxes at the sediment-water interface were much greater in the box with crabs than in the box without crabs.In summer,NH-N showed a positive flux from the sediment to the overlying water,but NO2-N and NOg-N showed positive fluxes from the sediment to the overlying water only in early stages.In winter,NH-N showed a positive flux from the sediment to the overlying water,but NO-N and NO,-N both exhibited positive and negative fluxes.These results indicated that the presence of crab burrows can cause the aerobic layer to move downward by approximately 8-15 cm in summer and directly promote nitrification at the sediment surface.

Fractionation of rare earth and other trace elements in crabs,Ucides cordatus,from a subtropical mangrove affected by fertilizer industry

Fractionation of rare earth elements（REE） and other trace metal concentrations（Th, U, Cd,Cr, Cu, Ni, Pb, and Zn） between mangrove sediments and claw muscles and shells of male crabs（Ucides cordatus） from a subtropical estuary highly impacted by fertilizer industry activities was investigated. This is the first record of REE distribution in these organisms,and the results showed higher accumulations of these metals, U and Th in shells, probably related to the replacement of Ca during molting. Contents of Cd, Cr and Ni were similar in both tissues, but Cu, Zn and Pb were mostly accumulated in the claw muscle with concentrations above those considered safe for human consumption according to the Brazilian legislation. REE fractionation was different in the analyzed tissues being softer in the shells. The results provided evidences that the water absorbed during molting controls the chemistry of REE in shells. In contrast, the chemistry of REE in the claw muscle, in which was observed preferential absorption of light REE, is controlled by diet. REE fractionation obtained for the claw muscles was closely correlated to the observed in the contaminated substrate and in materials related to the production of phosphate fertilizers（contamination source）, which supports their transference to this Ucides cordatus tissue without fractionation by the ingestion of sediments. Our results showed the potential use of crab tissues for monitoring REE and trace element sources in mangrove areas, with claw muscle exhibiting the contaminant source fingerprint.

The Science of Radio Astronomy: An Investigation of Crab Nebula

The science of radio astronomy focuses on the observation and study of celestial objects by reading their radio waves. The 5 meter radio-telescope is able to observe different radio sources using a C-band LNB. This research was essentially focused on Crab Nebula, also known as Taurus A. The study led to interesting observations, which were validated numerically using various scientific computing software. The radio waves emitted by Taurus A are readable by the RTL-SDR, a software defined radio receiver. This device is capable of reading radio frequencies in the range of 0.5 MHZ to 1700 MHZ.

The King of Crabs

An innovative entrepreneur and Party member’s tale of success amid hardships and obstacles Knowledge can change one’s life.That is how 46-year-old Li Xiaodong describes his rags-to-riches story. Li’s resume glows.He is