Rice (<i>Oryza sativa</i> L.) Breeding among Hassawi Landrace and Egyptian Genotypes for Stem Borer (<i>Chilo agamemnon</i> Bles.) Resistance and Related Quantitative Traits

Rice stem borer (Chilo agamemnon Bles.) is a primary insect pest of rice and is a major limiting factor to rice production. Breeding for insect-resistant crop varieties has been an economic way of integrated pest management (IPM) as it offers a viable and ecologically acceptable approach. This study was aimed to evaluate rice genotypes for their resistance against rice stem borer. Seven parental genotypes with twenty one F1 crosses were evaluated for genotypic variation in field experiments. Analysis of variance revealed significant differences for the studied traits in almost all crosses and parents. In addition, the mean squares of parents versus their crosses were signifi- cant for stem borer resistance and other associated traits. Moreover, both general combining ability (GCA) and specific combining ability (SCA) variances were highly significant for all characters studied in the F1 generation. Based on GCA, 4 genotypes (Sakha101, Gz6903-3-4-2-1, Gz9577-4-1-1 and Hassawi) exhibited highly significant negative values for stem borer resistance (–0.53, –1.06, –0.18 and –0.49, respectively) indicating they are the best combiners for stem borer resistance. Based on SCA analysis, nine cross combinations showed highly significant negative effects for stem borer resistance. Similarly, the cross Giza178 Hassawi was the best combination with significantly highest value for early maturity. In addition, seven crosses showed highly significant negative SCA for plant height trait. On the other hand, for panicle length, number of primary branches/panicle, panicle weight and 1000-grain weight, seven, four, eight and six crosses showed highly significant positive SCA, respectively. The result further revealed that the non-additive dominance genetic variance was higher than the additive variance for all evaluated traits indicating that non-additive genetic variances have a role in their inheritance. The broad-sense heritability estimates were high for all the studied traits. The stem borer resistance was significantly correlated with panicle weight and 1000-grain weight, which also showed a highly significant correlation with grain yield/plant. Thus these traits can be effectively employed in a breeding program to confer resistance against stem borer infestation in rice. It was further supported by biplot analysis, which clustered these potentially important traits into two quadrants showing their importance in any future breeding program to control stem borer infestation. This study has contributed valuable information for evaluation of genetic diversity in the local rice germplasm and its utilization in futuristic rice genetic improvement programs.     

Expression of LEKTI domains 6-9' in the baculovirus expression system: recombinant LEKTI domains 6-9' inhibit trypsin and subtilisin A

The precursor lympho-epithelial Kazal-type-related inhibitor (LEKTI), containing two Kazal-type and 13 nonKazal-type domains, is an efficient inhibitor of multiple serine proteinases, among them plasmin, subtilisin A, cathepsin G, elastase, and trypsin. To gain insight into the structure and function of some of these domains, a portion of the cDNA coding for LEKTI domains 6-9' was cloned and expressed in Sf9 cells using the baculovirus expression vector system (BEVS). Through a single purification step using a Co2+ column, 3-4 mg of purified recombinant LEKTI-domains 6-9' (rLEKTI6-9') with the predicted molecular mass of 34.6 kDa was obtained from the cell pellet of a 1-L culture. Unlike full-length LEKTI, rLEKTI6-9' inhibited trypsin and subtilisin A but not plasmin, cathepsin G, or elastase. The inhibition of trypsin and subtilisin A by rLEKTI6-9' occurred through a noncompetitive mechanism, with inhibitory constants (Ki) of 356 +/- 12 and 193 +/- 10 nM, respectively. On the basis of the Ki values, rLEKTI6-9' was determined to be a more potent trypsin inhibitor and a less potent subtilisin A inhibitor than the full-length LEKTI. In contrast to LEKTI domains 6-9', recombinant LEKTI domain 6 does not inhibit subtilisin A but competitively inhibited trypsin with a Ki of 200 +/- 10 nM. Taking LEKTI6-9' as an example, the BEVS should facilitate the structure-function analysis of naturally occurring processed LEKTI forms that have physiological relevance.     

Bisphosphonated fluoroquinolone esters as osteotropic prodrugs for the prevention of osteomyelitis

Osteomyelitis is a difficult to treat bacterial infection of the bone. Delivering antibacterial agents to the bone may overcome the difficulties in treating this illness by effectively concentrating the antibiotic at the site of infection and by limiting the toxicity that may result from systemic exposure to the large doses conventionally used. Using bisphosphonates as osteophilic functional groups, different forms of fluoroquinolone esters were synthesized and evaluated for their ability to bind bone and to release the parent antibacterial agent. Bisphosphonated glycolamide fluoroquinolone esters were found to present a profile consistent with effective and rapid bone binding and efficient release of the active drug moiety. They were assessed for their ability to prevent bone infection in vivo and were found to be effective when the free fluoroquinolones were not.     

Development and organization of polarity-specific segregation of primary vestibular afferent fibers in mice

A striking feature of vestibular hair cells is the polarized arrangement of their stereocilia as the basis for their directional sensitivity. In mammals, each of the vestibular end organs is characterized by a distinct distribution of these polarized cells. We utilized the technique of post-fixation transganglionic neuronal tracing with fluorescent lipid soluble dyes in embryonic and postnatal mice to investigate whether these polarity characteristics correlate with the pattern of connections between the endorgans and their central targets; the vestibular nuclei and cerebellum. We found that the cerebellar and brainstem projections develop independently from each other and have a non-overlapping distribution of neurons and afferents from E11.5 on. In addition, we show that the vestibular fibers projecting to the cerebellum originate preferentially from the lateral half of the utricular macula and the medial half of the saccular macula. In contrast, the brainstem vestibular afferents originate primarily from the medial half of the utricular macula and the lateral half of the saccular macula. This indicates that the line of hair cell polarity reversal within the striola region segregates almost mutually exclusive central projections. A possible interpretation of this feature is that this macular organization provides an inhibitory side-loop through the cerebellum to produce synergistic tuning effects in the vestibular nuclei. The canal cristae project to the brainstem vestibular nuclei and cerebellum, but the projection to the vestibulocerebellum originates preferentially from the superior half of each of the cristae. The reason for this pattern is not clear, but it may compensate for unequal activation of crista hair cells or may be an evolutionary atavism reflecting a different polarity organization in ancestral vertebrate ears.     

Curvature effect on hemodynamic conditions at the inner bend of the carotid siphon and its relation to aneurysm formation

Although high-impact hemodynamic forces are thought to lead to cerebral aneurysmal change, little is known about the aneurysm formation on the inner aspect of vascular bends such as the internal carotid artery (ICA) siphon where wall shear stress (WSS) is expected to be low. This study evaluates the effect of vessel curvature and hemodynamics on aneurysm formation along the inner carotid siphon. Catheter 3D-rotational angiographic volumes of 35 ICA (10 aneurysms, 25 controls) were evaluated in 3D for radius of curvature and peak curvature of the siphon bend, followed by univariate statistical analysis. Computational fluid dynamic (CFD) simulations were performed on patient-derived models after aneurysm removal and on synthetic variants of increasing curvature. Peak focal siphon curvature was significantly higher in aneurysm bearing ICAs (0.36±0.045 vs. 0.30±0.048 mm⁻¹, p=0.003), with no difference in global radius of curvature (p=0.36). In CFD simulations, increasing parametric curvature tightness (from 5 to 3 mm radius) resulted in dramatic increase of WSS and WSS gradient magnitude (WSSG) on the inner wall of the bend. In patient-derived data, the location of aneurysms coincided with regions of low WSS (<4 Pa) flanked by high WSS and WSSG peaks. WSS peaks correlated with the aneurysm neck. In contrast, control siphon bends displayed low, almost constant, WSS and WSSG profiles with little spatial variation. High bend curvature induces dynamically fluctuating high proximal WSS and WSSG followed by regions of flow stasis and recirculation, leading to local conditions known to induce destructive vessel wall remodeling and aneurysmal initiation.     

Sensitivity of cultured pancreatic carcinoma cells toAcinetobacter glutaminase-asparaginase

Summary Cultured human pancreatic carcinoma cells (MIA PaCa-2) have been shown previously to be very sensitive toE. coli l-asparaginase (EC II). The present studies have demonstrated that another enzyme,Acinetobacter glutaminase-asparaginase (AGA) is much more effective in inhibiting cell growth. At the concentration of 0.0025 U/ml of AGA activity the enzyme totally inhibited cell growth, whereas the EC II with the same concentration did not show any effect. The inhibition of cell growth correlated well with inhibition of protein and glycoprotein synthesis. The addition ofl-glutamine at the concentration of 1 mM completely reversed the inhibition of protein synthesis. Similarly, the addition ofl-glutamine at the concentration of 3 mM daily on 3 successive days after adding AGA resulted in significant reversal of growth inhibition. The results of this study indicate that the action of AGA on MIA PaCa-2 is, to a great extent, exerted through itsl-glutaminase activity. This work was supported in part by USPHS Grant CA 19182. Dr. Wu is recipient of Research Career Development Award Grant CA00686 and Dr. Yunis is a Howard Hughes Investigator.     

A versatile synthetic route to chiral quinoxaline derivatives from amino acids precursors

Summary The synthesis ofN-protected L-amino acid (3-benzylquinoxalin-2-yl) hydrazide derivatives is reported here. 3-Benzyl-2-hydrazinoquinoxaline was prepared and then coupled withN-Boc-L-amino acids including; Alanine, Valine, Leucine, Phenylalanine, Tyrosine, Serine and Proline in the presence of HBTU as a coupling reagent to provide the expected product with high yield and purity. The products were deprotected by p-toluenesulphonic acid in acetonitrile and then the tosylate salts were evaluated for antibacterial and antifungal activity. Abbreviations: HBTU, N-[(1H-benzotriazol-1-yl)(dimethylamino)methylene]-N-methylmethanaminium hexafluorophosphate N-oxide Boc,t-butyloxycarbonyl, DIEA, diisopropylethylamine; DMF, N,N-dimethylformamide; PTSA, p-toluenesulphonic acid, TEA, triethyl amine. Amino acids are abbreviated and designated following the rules of the IUPAC-IUB Commission of BiochemicalNomenclature (J. Biol. Chem., 247 (1972) 977).     

Tectorigenin inhibits RANKL‐induced osteoclastogenesis via suppression of NF‐κB signalling and decreases bone loss in ovariectomized C57BL/6

Metabolism of bone is regulated by the balance between osteoblast‐mediated bone formation and osteoclast‐mediated bone resorption. Activation of osteoclasts could lead to osteoporosis. Thus, inhibiting the activity of osteoclasts becomes an available strategy for the treatment of osteoporosis. Tectorigenin is an extract of Belamcanda chinensis In the present study, the anti‐osteoclastogenesis effects of tectorigenin were investigated in vitro and in vivo. The results showed preventive and therapeutic effects of tectorigenin at concentrations of 0, 10, 40, and 80 μmol/L in the maturation and activation of osteoclasts. A signalling study also indicated that tectorigenin treatment reduces activation of NF‐κB signalling in osteoclastogenesis. Animal experiment demonstrated that tectorigenin treatment (1‐10 mg/kg, abdominal injection every 3 days) significantly inhibits bone loss in ovariectomized C57BL/6. Our data suggest that tectorigenin is a potential pharmacological choice for osteoporosis.     

Age patterns of Cryptosporidium species and Giardia duodenalis in dairy calves in Egypt

Little is known of the occurrence and age patterns of species/genotypes and subtypes of Cryptosporidium spp. and Giardia duodenalis in calves in Egypt. In this study, 248 fecal specimens were collected from dairy calves aged 1?day to 6?months on eight farms in three provinces during March 2015 to April 2016. Cryptosporidium spp. were detected and genotyped by using PCR-RFLP analysis of the small subunit rRNA (SSU rRNA) gene, while G. duodenalis was detected and genotyped by using PCR and sequence analyses of the triose phosphate isomerase (tpi), glutamate dehydrogenase (gdh) and β-giardin (bg) genes. The overall infection rates of Cryptosporidium spp. and G. duodenalis were 9.7 and 13.3%, respectively. The highest Cryptosporidium infection rate (26.7%) was in calves of age?≤?1?month while the highest G. duodenalis infection rate (44.4%) was in calves of 2?months. Three Cryptosporidium spp. were identified, including C. parvum (n?=?16), C. bovis (n?=?5) and C. ryanae (n?=?3), with the former being almost exclusively found in calves of ≤3?months of age and the latter two being only found in calves of over 3?months. Subtyping of C. parvum by PCR-sequence analysis of the 60?kDa glycoprotein gene identified subtypes IIaA15G1R1 (n?=?15) and IIaA15G2R1 (n?=?1). The G. duodenalis identified included both assemblages E (n?=?32) and A (n?=?1), with the latter belonging to the anthroponotic subtype A2. These data provide new insights into the genetic diversity and age patterns of Cryptosporidium spp. and G. duodenalis in calves in Egypt.     

Mdm2 and Mdm4 loss regulates distinct p53 activities

Mutational inactivation of p53 is a hallmark of most human tumors. Loss of p53 function also occurs by overexpression of negative regulators such as MDM2 and MDM4. Deletion of Mdm2 or Mdm4 in mice results in p53-dependent embryo lethality due to constitutive p53 activity. However, Mdm2(-/-) and Mdm4(-/-) embryos display divergent phenotypes, suggesting that Mdm2 and Mdm4 exert distinct control over p53. To explore the interaction between Mdm2 and Mdm4 in p53 regulation, we first generated mice and cells that are triple null for p53, Mdm2, and Mdm4. These mice had identical survival curves and tumor spectrum as p53(-/-) mice, substantiating the principal role of Mdm2 and Mdm4 as negative p53 regulators. We next generated mouse embryo fibroblasts null for p53 with deletions of Mdm2, Mdm4, or both; introduced a retrovirus expressing a temperature-sensitive p53 mutant, p53A135V; and examined p53 stability and activity. In this system, p53 activated distinct target genes, leading to apoptosis in cells lacking Mdm2 and a cell cycle arrest in cells lacking Mdm4. Cells lacking both Mdm2 and Mdm4 had a stable p53 that initiated apoptosis similar to Mdm2-null cells. Additionally, stabilization of p53 in cells lacking Mdm4 with the Mdm2 antagonist nutlin-3 was sufficient to induce a cell death response. These data further differentiate the roles of Mdm2 and Mdm4 in the regulation of p53 activities.