Induction of spawning in Pacific white shrimp Litopenaeus vannamei (Boone, 1931) by injection of its molt inhibiting hormone isoform II produced in E. coli

The optimization of reproductive parameters in shrimp farming continues to be a challenge for most producing countries. Although the crustacean neuropeptides have been studied extensively in the last two decades, the functions of most of these neuropeptides remained putative. Among them, molt‐inhibiting hormone isoform II (MIH II) has shown an important role in vitellogenesis. In this study, the cDNA encoding mature MIH II peptide was isolated by RT‐PCR from the L. vannamei eyestalk. The cDNA was cloned into pET28a bacterial expression vector. Recombinant MIH II was obtained in the form of insoluble inclusion bodies and purified to ~88% purity. Two doses of rMIH II and a negative control group were assayed in vivo. The stages of ovarian maturation and spawning were recorded during 72 hr post‐injection. The results showed that ovarian maturation occurred approximately in 9% and 33% of females injected with rMIH II at the doses of 300 and 600 ng/gbw respectively. Neither maturation nor spawning was detected in the negative control group. Females injected with 600 ng/gbw, which showed vitellogenic stages III and IV, spawned. These preliminary results argue that the hormone rMIH II could be a promising candidate to induce spawning in L. vannamei shrimp.     

Evaluation of Different Inoculation Methods for Screening of Sclerotinia rot and Phytophthora blight in Perilla Germplasm

Journal of Crop Science and Biotechnology - Sclerotinia rot and Phytophthora blight are devastating diseases of perilla that can cause huge loss of perilla production. Screening disease resistant...     

Nematode community composition and diversity associated with a topoclimatic transect in a rain shadow desert

The effect of a topoclimatic gradient on soil nematode communities was investigated in the Israeli Judean Desert. Four locations along a 35 km gradient, from an elevation of 650 m above sea level with 620 mm rainfall to a –60 m relative to sea level with a rainfall below 110 m, were studied: Givat Yearim, Maale Adumim, Mishor Adumim and Kalia. Monthly soil samples were collected between January 1994 and December 1995. Thirteen nematode families and 17 genera were observed. Cephalobus, Heterocephalobus, Aphelenchoides, Tylenchus, Dorylaimus and Eudorylaimus were found to be the dominant genera. Ecological measurements of soil nematode community structure, diversity, and maturity indices were assessed, and comparisons between four locations and four seasons were made. Significant differences in the total numbers of nematodes were found between the locations (p < 0.01) and seasons (p < 0.05), where Givat Yearim > Maale Adumim > Mishor Adumim > Kalia, winter > spring > autumn > summer. Bacterivores were found to be the most abundant trophic group across locations and seasons, with a mean relative abundance of 55.0%. The densities of bacterivores, plant parasites and omnivores-predators during the winter season exhibited similar trends at all four locations, with Givat Yearim > Maale Adumim > Mishor Adumim > Kalia. None of the ecological indices were significantly different between locations. However, the maturity index (MI), trophic diversity (TD) and Simpson diversity (SI) exhibited significant differences between seasons.     

Evolutionarily assembled cis-regulatory module at a human ciliopathy locus

Neighboring genes are often coordinately expressed within cis-regulatory modules, but evidence that nonparalogous genes share functions in mammals is lacking. Here, we report that mutation of either TMEM138 or TMEM216 causes a phenotypically indistinguishable human ciliopathy, Joubert syndrome. Despite a lack of sequence homology, the genes are aligned in a head-to-tail configuration and joined by chromosomal rearrangement at the amphibian-to-reptile evolutionary transition. Expression of the two genes is mediated by a conserved regulatory element in the noncoding intergenic region. Coordinated expression is important for their interdependent cellular role in vesicular transport to primary cilia. Hence, during vertebrate evolution of genes involved in ciliogenesis, nonparalogous genes were arranged to a functional gene cluster with shared regulatory elements.     

Characterization of Haemophilus parasuis isolated from Brazilian swine through serotyping, AFLP and PFGE

Haemophilus parasuis infection in pigs is characterized by fibrinous polyserositis, arthritis and meningitis. Despite the fact that traditional diagnosis is based on herd history, clinical signs, bacterial isolation and serotyping, molecular-based methods are alternatives for species-specific tests and epidemiological studies. The aim of this study was to characterize H. parasuis field strains from different states of Brazil, employing serotyping and genotyping methods. Serotyping revealed that serovar 4 was the most prevalent (26.1%), followed by serovars 5 (17.4%), 14 (8.7%), 13 (4.4%) and 2 (4.4%), whereas 39% of the strains were considered as untypeable. AFLP with a single enzyme and PFGE were able to type all isolates tested, generating 34 and 20 different profiles, respectively, including untypeable strains. Besides the slightly higher discrimination index presented by AFLP, PFGE with Not I restriction enzyme showed a better correlation with epidemiological data, grouping strains of the same serovar, animal or farm origin. The results indicated AFLP and PFGE as valuable tools for typing H. parasuis isolates collected in Brazil.     

The Weedy Rice Complex in Costa Rica. I. Morphological Study of Relationships Between Commercial Rice Varieties,Wild <Emphasis Type="Italic">Oryza</Emphasis> Relatives and Weedy Types

Weedy rice is a complex of Oryza morphotypes widely distributed in commercial rice fields, which interfere with rice cultivation, seed production, industrial processing and commercialization of this crop in several countries. The objective of this study was to characterize the weedy rice complex of Costa Rica by comparing it with the cultivated and wild rice species found in the country. A collection of weedy rice accessions, representative of the morphotypes found in the country, was established and characterized. Their morphometric relationships were established by comparing 27 morphological traits with commercial rice cultivars, landraces and wild Oryza species and by performing a multivariate analysis. Twenty-one weedy rice morphotypes were identified among 735 weedy accessions by using a three-digit code based on seed characters. Three principal components (PCs) explained 66.25% of the variation observed. The first PC accounted for 36.21% of the variation and separated CCDD genome type Oryza latifolia and O. grandiglumis from AA genome species O. sativa, O. glumaepatula, O. rufipogon and O. glaberrima. The second (18.9%) and third (11.14%) PCs separated the weedy morphotype groups from the AA genome species O.sativa, O. glaberrima and O. rufipogon. The weedy morphotypes were scattered between the indica commercial rice varieties, the cluster landraces–glaberrima and O. rufipogon. Additionally, a group of morphotypes showed intermediate characteristics between O. sativa and O. rufipogon, suggesting that hybridization could have taken place in the past between these species. None of the morphotypes collected in Costa Rica clustered with the allotetraploids CCDD species or O. glumaepatula.     

Truncating neurotrypsin mutation in autosomal recessive nonsyndromic mental retardation

A 4-base pair deletion in the neuronal serine protease neurotrypsin gene was associated with autosomal recessive nonsyndromic mental retardation (MR). In situ hybridization experiments on human fetal brains showed that neurotrypsin was highly expressed in brain structures involved in learning and memory. Immuno-electron microscopy on adult human brain sections revealed that neurotrypsin is located in presynaptic nerve endings, particularly over the presynaptic membrane lining the synaptic cleft. These findings suggest that neurotrypsin-mediated proteolysis is required for normal synaptic function and suggest potential insights into the pathophysiological bases of mental retardation.     

Cyanobacteria from Terrestrial and Marine Sources Contain Apoptogens Able to Overcome Chemoresistance in Acute Myeloid Leukemia Cells

In this study, we investigated forty cyanobacterial isolates from biofilms, gastropods, brackish water and symbiotic lichen habitats. Their aqueous and organic extracts were used to screen for apoptosis-inducing activity against acute myeloid leukemia cells. A total of 28 extracts showed cytotoxicity against rat acute myeloid leukemia (IPC-81) cells. The design of the screen made it possible to eliminate known toxins, such as microcystins and nodularin, or known metabolites with anti-leukemic activity, such as adenosine and its analogs. A cytotoxicity test on human embryonic kidney (HEK293T) fibroblasts indicated that 21 of the 28 extracts containing anti-acute myeloid leukemia (AML) activity showed selectivity in favor of leukemia cells. Extracts L26-O and L30-O were able to partly overcome the chemotherapy resistance induced by the oncogenic protein Bcl-2, whereas extract L1-O overcame protection from the deletion of the tumor suppressor protein p53. In conclusion, cyanobacteria are a prolific resource for anti-leukemia compounds that have potential for pharmaceutical applications. Based on the variety of cellular responses, we also conclude that the different anti-leukemic compounds in the cyanobacterial extracts target different elements of the death machinery of mammalian cells.