Pathophysiology of enteropathogenic Escherichia coli during a host infection

Enteropathogenic Escherichia coli (EPEC) is a major cause of infantile diarrhea in developing countries. However, sporadic outbreaks caused by this microorganism in developed countries are frequently reported recently. As an important zoonotic pathogen, EPEC is being monitored annually in several countries. Hallmark of EPEC infection is formation of attaching and effacing (A/E) lesions on the small intestine. To establish A/E lesions during a gastrointestinal tract (GIT) infeciton, EPEC must thrive in diverse GIT environments. A variety of stress responses by EPEC have been reported. These responses play significant roles in helping E. coli pass through GIT environments and establishing E. coli infection. Stringent response is one of those responses. It is mediated by guanosine tetraphosphate. Interestingly, previous studies have demonstrated that stringent response is a universal virulence regulatory mechanism present in many bacterial pathogens including EPEC. However, biological signficance of a bacterial stringent response in both EPEC and its interaction with the host during a GIT infection is unclear. It needs to be elucidated to broaden our insight to EPEC pathogenesis. In this review, diverse responses, including stringent response, of EPEC during a GIT infection are discussed to provide a new insight into EPEC pathophysiology in the GIT.     

Gross Anatomy of the Pancreatic Lobes and Ducts in Six Breeds of Domestic Ducks and Six Species of Wild Ducks in China

A previously unreported pancreatic duct was found by Liu (1989) in Pekin ducks. This duct has now been consistently found in six breeds of domestic ducks and six species of wild ducks in China. For purposes of Nomina Anatomica Avium it is hereby called the ‘first pancreatic duct’(Ducius pancreaticus primus) since it enters the duodenum at or near the flexure where the descending duodenum becomes the ascending duodenum. All other pancreatic ducts enter the duodenum later, closer to where it joins the jejunum. This first pancreatic duct drains the caudal extremity of the dorsal lobe of the pancreas and can be easily exteriorized for experimental purposes. Within the parenchyma of the dorsal lobe of the pancreas this duct communicates with the dorsal pancreatic duct. In the present study of the gross anatomy of the pancreatic lobes of domestic and wild Chinese ducks we describe and illustrate variations in position and number of all biliary and pancreatic ducts.     

Characterization of betaine aldehyde dehydrogenase (BetB) as an essential virulence factor of Brucella abortus

The pathogenic mechanisms of Brucellosis used to adapt to the harsh intracellular environment of the host cell are not fully understood. The present study investigated the in vitro and in vivo characteristics of B. abortus betaine aldehyde dehydrogenase (BetB) (Gene Bank ID: 006932) using a betB deletion mutant constructed from virulent B. abortus 544. In test under stress conditions, including osmotic- and acid stress-resistance, the betB mutant had a lower osmotic-resistance than B. abortus wild-type. In addition, the betB mutant showed higher internalization rates compared to the wild-type strain; however, it also displayed replication failures in HeLa cells and RAW 264.7 macrophages. During internalization, compared to the wild-type strain, the betB mutant was more adherent to the host surface and showed enhanced phosphorylation of protein kinases, two processes that promote phagocytic activity, in host cells. During intracellular trafficking, colocalization of B. abortus-containing phagosomes with LAMP-1 was elevated in betB mutant-infected cells compared to the wild-type cells. In mice, the betB mutant was predominantly cleared from spleens compared to the wild-type strain after 2 weeks post-infection, and the vaccination test with the live betB mutant showed effective protection against challenge infection with the virulent wild-type strain. These findings suggested that the B. abortus betB gene substantially affects the phagocytic pathway in human phagocytes and in host cells in mice. Furthermore, this study highlights the potential use of the B. abortus betB mutant as a live vaccine for the control of brucellosis.     

Effects of interspecific competition on the growth and competitiveness of five emergent macrophytes in a constructed lentic wetland

To evaluate the performance of new rice establishment methods viz., system of rice intensification (SRI) and integrated crop management (ICM), a field study was conducted during 2008–11 in South Garo Hills, Meghalaya, foot hills of Eastern Himalayas, India. Field demonstrations were undertaken during wet seasons of 2008–11 and socio-economic information in the context of farmer’s realities were obtained during 2010–11 using a well structured questionnaire administered to 134 farmers. The results indicated that the average higher productivity of rice under SRI and ICM demonstration was 209.9 and 185.4 %, respectively, over conventional rice culture (CRC). The SRI and ICM methods of rice cultivation could save seeds (97.56 and 60.98 %), saving water (78.05 and 63.66 %), reduce cost (70.33 %), higher yield etc. compared to CRC. The main reasons for non-adoption of SRI/ICM was related to involvement of more efforts, faith towards traditional practices, ignorance and lack of knowledge on scientific water management. The net-return of $816.69, $706.63 and $51.48/ha was realized under SRI, ICM and CRC, respectively. The co-efficient of multiple determinations (R ²) of the production function was 0.695 in SRI, 0.714 in ICM and 0.734 in CRC which indicated that about 69.5, 71.4 and 73.4 % of the variation in rice productivity under SRI, ICM and CRC, respectively were explained by the independent variable and remaining 30.5, 28.6 and 26.6 %., respectively in SRI, ICM and CRC were as a result of non-inclusion of some explanatory variables as well as other factors outside the farmers control.     

DNA profiling and genetic diversity of Korean soybean (<Emphasis Type="Italic">Glycine max</Emphasis> (L.) Merrill) landraces by SSR markers

Approximately 7,000 accessions of Korean soybean (Glycine max (L.) Merrill) landraces, largely composed of three collections, the Korea Atomic Energy Research Institute’s soybean (KAS), the Korean Crop Experiment Station’s soybean (KLS) and the Korean Agricultural Development and Technology Center’s soybean (KADTC) collections, have been conserved at the Rural Development Administration (RDA) genebank in Korea. The accessions within collections were classified based on their traditional uses such as sauce soybean (SA), sprouted soybean (SP), soybean for cooking with rice (SCR), and OTHERS. A total of 2,758 accessions of Korean soybean landraces were used to profile and to evaluate genetic structure using six SSR loci. A total of 110 alleles were revealed by at the six SSR loci. The number of alleles per SSR locus ranged from 9 to 39 in Satt187 and Satt_074, respectively. The number of alleles ranged from 87 in the KADTC collection to 96 in the KLS collection, and from 63 in the SCR group to 95 in the SP group. Nei’s average genetic diversity ranged from 0.68 to 0.70 across three collections, and 0.64 to 0.69 across the usage groups. The average between-group differentiation (G _st) was 0.9 among collections, and 4.1 among the usage groups. The similar average diversity among three collections implies that the genetic background of the three collections was quite similar or that there were a large number of duplicate accessions in three collections. The selection from the four groups classified based upon usage may be a useful way to select accessions for developing a Korean soybean landrace core collection at the RDA genebank. DNA profile information of accessions will provide indications of redundancies or omissions and aid in managing the soybean collection held at the RDA genebank. The information on diversity analysis could help to enlarge the genetic diversity of materials in breeding programs and could be used to develop a core collection.     

Breeding of tetra null soybean (Glycine max) for lipoxygenase,kunitz trypsin inhibitor,lectin, and 7S α' subunit proteins

Soybean seed includes various bioactive substances. Also, they contain a variety of antinutritional factors including lipoxygenase, Kunitz trypsin inhibitor (KTI), lectin, and 7S α' subunit proteins. The genetic removal of these proteins will improve the nutritional value of soybean seed. The objective of this research was to breed new soybean with tetra recessive alleles (lox1lox2lox3/lox1lox2lox3‐ti/ti‐le/le‐cgy1/cgy1) for lipoxygenase, KTI, lectin, and 7S α' subunit proteins. Seven parents were used to breed tetra null strain. SDS‐PAGE and Western blot analysis were used to determine the presence or absence of lipoxygenase, 7S α' subunit, KTI, and lectin proteins in mature seed. Tetra null soybean line has a purple flower, determinate growth habit, tan pod, and yellow seed coat colour. Stem height of the breeding line was 62.3 cm. The 100‐seed weight of the breeding line was 27.1 g and yield (t/ha) was 2.84. This is the first soybean strain with lox1lox2lox3/lox1lox2lox3‐ti/ti‐le/le‐cgy1/cgy1 genotype (absence of lipoxygenase, KTI, lectin, and 7S α' subunit proteins).     

Antimetastatic Effect of Halichondramide,a Trisoxazole Macrolide from the Marine Sponge Chondrosia corticata,on Human Prostate Cancer Cells via Modulation of Epithelial-to-Mesenchymal Transition

Halichondramide (HCA), a trisoxazole-containing macrolide isolated from the marine sponge Chondrosia corticata has been shown to exhibit cytotoxicity and antifungal activities. In our previous study, HCA was also found to exhibit antiproliferative activity against a variety of cancer cells. However, the precise mechanism of action of HCA in the antitumor activity remains to be elucidated. In the present study, we identified the antimetastatic activity of HCA in the highly metastatic PC3 human prostate cancer cells. HCA showed potent growth inhibitory activity of the PC3 cells with an IC₅₀ value of 0.81 µM. Further analysis revealed that HCA suppressed the expression of a potential metastatic biomarker, phosphatase of regenerating liver-3 (PRL-3), in PC3 cells. The suppression of PRL-3 by HCA sequentially down-regulates the expression of phosphoinositide 3-kinase (PI3K) subunits p85 and p110. The antimetastatic effect of HCA was also correlated with the down-regulation of matrix metalloproteases (MMPs) and the modulation of cadherin switches N-cadherin and E-cadherin. In addition, HCA also effectively suppressed the migration and invasion of PC3 cells. These findings suggest that halichondramide might serve as a potential inhibitor of tumor cell metastasis with the modulation of PRL-3.