Cloning and Functional Characterization of Pcficolin1 and Pcficolin2 in red swamp crayfish (Procambarus clarkii).

The SNP polymorphisms associated with WSSV-resistance of prophenoloxidase in red swamp crayfish (Procambarus clarkii) and its immune response against white spot syndrome virus (WSSV)

Identification of Cdc42 in the red swamp crayfish (Procambarus clarkii) and its roles in phagocytosis and apoptosis.

Effects of dietary oregano essential oil on digestive tissue structure and function, antioxidant and immune responses and gut microbiota of red swamp crayfish (Procambarus clarkii).

The red swamp crayfish (Procambarus clarkii) was introduced to China in the early 20th century. It has been spread to almost all forms of fresh water bodies including lakes, rivers and even paddyfields in most provinces of China. To clarify issues such as the initial entry point(s), dispersal pattern, genetic diversity and genetic structure of Procambarus clarkii in China, the genetic structure and diversity of P. clarkii populations at 37 sampling sites (35 from China, one from the USA and one from Japan) were analyzed using both mitochondrial gene sequences (COI and 16S rRNA) and 12 nuclear microsatellites. Multiple tests including phylogenetic analyses, Bayesian assignment and analysis of isolation by distance showed that (i) the population from Japan and those collected from China, particularly from NanJing (BGt and XG) and its some neighboring sites (CJr, NT and NB), have similar genetic composition, (ii) relatively high genetic diversity was detected in Chinese populations, (iii) the P. clarkii populations in China did not experience significant population expansions. Taken together, Nanjing, Jiangsu province is the presumed initial entry point, and human-mediated dispersal and adaptive variation are likely responsible for the observed genetic pattern of P. clarkii in China.

Geographic origin discrimination of red swamp crayfish Procambarus clarkii from different Chinese regions using mineral element analysis assisted by machine learning techniques

Biological invasions are a significant component of current global environmental change that affect biodiversity as well as ecosystem processes and services. The red swamp crayfish (Procambarus clarkii) is one of the most invasive species worldwide, with a documented ability to deplete basal food resources and alter the structure of aquatic food webs. The red swamp crayfish has extensively invaded the Poyang Lake wetland, located in the middle reach of the Yangtze River basin. Here, we use an isotopic mixing model (MixSIAR) with data from stable isotope ratios (δ13C, δ15N) to estimate relative contributions of potential resources to the biomass of red swamp crayfish and ten common native species, and we use hierarchical clustering analysis to assess basal resource breadth and interspecific similarity of invasive and native species. We hypothesized that red swamp crayfish and several native species have similar trophic niches and may compete for basal resources. Results from the mixing model demonstrated seasonal variation in the basal resource of all species, including the red swamp crayfish and native snails, prawns, and fishes. Submerged macrophytes and detritus were estimated to be the most important sources during the rising-water season; during the high-water season, emergent macrophytes and detritus were most important; and during the falling-water season, detritus, POM, and floating macrophytes were most important. Resource overlap was substantial between the invasive crayfish and dominant native species, particularly the freshwater snail (Bellamya aeruginosa), indicating the potential exists for negative impact from competition under conditions of resource limitation.

Involvement of peroxinectin in the defence of red swamp crayfish Procambarus clarkii against pathogenic Aeromonas hydrophila

The red swamp crayfish (Procambarus clarkii) is an exceptionally invasive species introduced into the Egyptian freshwater ecosystems in the 1980s for aquaculture purposes. Despite its ecological and economic significance, the age distribution of this species has not been assessed properly using an accurate method. This study is the first to validate the use of growth band counts in the mesocardiac ossicles as a direct technique for age determination in P. clarkii using 166 known-age individuals reared under various temperature regimes. The findings confirm that band counts represent age rather than number of molts. Field comparisons between northern (Giza) and southern (Aswan) Nile populations revealed maximum longevities of six and seven years, respectively, using direct methods, while indirect size–frequency analysis underestimated age at three years. Growth rates were higher at 25 °C compared to 32 °C, both in the lab and in situ. Males matured at larger sizes than females, though age at sexual maturity averaged one year in both regions. This study demonstrates the superiority of direct aging over traditional indirect aging methods, offering critical insights for managing crayfish populations and ensuring sustainable fisheries in the River Nile in Egypt.

Transcriptomic information from the ovaries of red swamp crayfish (Procambarus clarkii) provides new insights into development of ovaries and embryos

In 2005, I conducted a baseline survey of crayfish stocks in Pine Lake, King County, Washington, which was invaded by red swamp crayfish (Procambarus clarkii) during the 1990s. Irrespective of the gear type used for sampling, the invader outnumbered the native signal crayfish (Pacifastacus leniusculus). This is the first account of an invasive species of crayfish dominating the signal crayfish inside of its natural range.

Virome analysis unveils a rich array of newly identified viruses in the red swamp crayfish Procambarus clarkii

Invasive alien crayfish species pose major ecological and hydrological risks globally. The red swamp crayfish (Procambarus clarkii) is one of the most widespread crayfish species worldwide. Its impacts arise from burrowing activities and lead to mobilization of soil nutrients, water safety risks by instability of dikes and erosion of banks. Increased sediment load demands additional dredging of drainage ditches and canals to ensure their water discharge capacity. Sustainable methods for limiting burrowing in banks and dispersal behaviour of crayfish were not yet available. Therefore, a field study was performed to determine whether the number of burrows and overland movement of crayfish were related to a particular bank type. Burrows were counted in three watercourses during a water-level decline. The number of burrows was significantly lower in natural banks than in non-natural and semi-natural banks. The construction of natural-like banks along watercourses may significantly reduce sediment load, erosion and the collapse of banks by burrowing activities of crayfish. An inclination experiment mimicking various types of terrestrial dispersal barriers elucidated that steepness, soil type and vegetation structure of small embankments near watercourses were significant factors for manipulating overland movement of crayfish. Crayfish were taken out of the water for this purpose and placed on small experimental embankments varying in slope and types of vegetation. The lowest frequencies of upward movement were recorded at inclinations of 20° and 30° on bare sandy soil and short and species-poor grassland substrates. This implies that crayfish crawling out of the water will return to the watercourse when encountering such a dispersal barrier. Therefore, a sophisticated design of embankments along watercourses can be a tool to reduce colonization risk of nearby located, hydrologically isolated water bodies with high nature values.

Oxidative damage induced by copper in testis of the red swamp crayfish Procambarus clarkii and its underlying mechanisms

Vitellogenin (Vg) is the precursor of vitellin, the major yolk protein. The site of Vg synthesis in crustaceans remains controversial. This study investigated the synthesis site of Vg in female red swamp crayfish Procambarus clarkii (Girard, 1852). Results revealed that the mRNA of Vg was detected in the tissues of hepatopancreas of P. clarkii. The mRNA expression level of Vg increased in the previtellogenic stage and peaked in the vitellogenic stage in the hepatopancreas and ovary; the mRNA expression level of Vg in the hepatopancreas was approximately 20-25-fold of that of the ovary in the same ovarian stage. Eyestalk ablation could upregulate the mRNA expression level of Vg in both organs. Our RNAi experiment verified that the hepatopancreas and ovary are the Vg synthesis sites in female P. clarkii.

Iron-binding proteins, known as ferritins, play pivotal roles in immunological response, detoxification, and iron storage. Despite their significance to organisms, little is known about how they affect the immunological system of the red swamp crayfish (Procambarus clarkii). In our previous research, one ferritin subunit was completely discovered as an H-like subunit (PcFeH) from P. clarkii. The full-length cDNA of PcFerH is 1779 bp, including a 5'-UTR (untranslated region, UTR) of 89 bp, 3'-UTR (untranslated region, UTR) of 1180 bp and an ORF (open reading frame, ORF) of 510 bp encoding a polypeptide of 169 amino acids that contains a signal peptide and a Ferritin domain. The deduced PcFerH protein sequence has highly identity with other crayfish. PcFerH protein's estimated tertiary structure is quite comparable to animal structure. The PcFerH is close to Cherax quadricarinatus, according to phylogenetic analysis. All the organs examined showed widespread expression of PcFerH mRNA, with the ovary exhibiting the highest levels of expression. Additionally, in crayfish muscles, intestines, and gills, the mRNA transcript of PcFerH was noticeably up-regulated, after LPS and Poly I:C challenge. The expression of downstream genes in the immunological signaling system was suppressed when the PcFerH gene was knocked down. All of these findings suggested that PcFerH played a vital role in regulating the expression of downstream effectors in the immunological signaling pathway of crayfish.