Type Of Sterility Research Articles

Effects of sterilization on poly(ethylene glycol) hydrogels

The past few decades have witnessed a dramatic increase in the development of polymeric biomaterials. These biomaterials have to undergo a sterilization procedure before implantation. However, many sterilization procedures have been shown to profoundly affect polymer properties. Poly(ethylene glycol) hydrogels have gained increasing importance in the controlled delivery of therapeutics and in tissue engineering. We evaluated the effect of ethylene oxide (EtO), hydrogen peroxide (H(2)O(2)), and gamma sterilization of poly(ethylene glycol) hydrogels on properties relevant to controlled drug delivery and tissue engineering. We observed that the release of cyclosporine (CyA) (an immunosuppressive drug that is effective in combating tissue rejection following organ transplantation) was significantly affected by the type of sterilization. However, that was not the case with rhodamine B, a dye. Hence, the drug release characteristics were observed to be dependent not only on the sterilization procedure but also on the type of agent that needs to be delivered. In addition, differences in the swelling ratios for the sterilized and unsterilized hydrogels were statistically significant for 1:1 crosslinked hydrogels derived from the 8000 MW polymer. Significant differences were also observed for gamma sterilization for 1:1 crosslinked hydrogels derived from the 3350 MW polymer and also the 2:1 crosslinked hydrogels derived from the 8000 MW polymer. Atomic force microscopy (AFM) studies revealed that the roughness parameter for the unsterilized and EtO-sterilized PEG hydrogels remained similar. However, a statistically significant reduction of the roughness parameter was observed for the H(2)O(2) and gamma-sterilized samples. Electron spin resonance (ESR) studies on the unsterilized and the sterilized samples revealed the presence of the peroxy and the triphenyl methyl carbon radical in the samples. The gamma and the H(2)O(2)-sterilized samples were observed to have a much higher concentration of the radical pecies when compared with the EtO and the unsterilized samples.

Mitochondrial nad2 gene is co-transcripted with CMS-associated orfB gene in cytoplasmic male-sterile stem mustard (Brassica juncea)

The transcriptional patterns of mitochondrial respiratory related genes were investigated in cytoplasmic male-sterile and fertile maintainer lines of stem mustard, Brassica juncea. There were numerous differences in nad2 (subunit 2 of NADH dehydrogenase) between stem mustard CMS and its maintainer line. One novel open reading frame, hereafter named orfB gene, was located at the downstream of mitochondrial nad2 gene in the CMS. The novel orfB gene had high similarity with YMF19 family protein, orfB in Raphanus sativus, Helianthus annuus, Nicotiana tabacum and Beta vulgaris, orfB-CMS in Daucus carota, atp8 gene in Arabidopsis thaliana, 5' flanking of orf224 in B. napus (nap CMS) and 5' flanking of orf220 gene in CMS Brassica juncea. Three copies probed by specific fragment (amplified by primers of nad2F and nad2R from CMS) were found in the CMS line following Southern blotting digested with HindIII, but only a single copy in its maintainer line. Meanwhile, two transcripts were shown in the CMS line following Northern blotting while only one transcript was detected in the maintainer line, which were probed by specific fragment (amplified by primers of nad2F and nad2R from CMS). Meanwhile, the expression of nad2 gene was reduced in CMS bud compared to that in its maintainer line. We thus suggested that nad2 gene may be co-transcripted with CMS-associated orfB gene in the CMS. In addition, the specific fragment that was amplified by primers of nad2F and nad2R just spanned partial sequences of nad2 gene and orfB gene. Such alterations in the nad2 gene would impact the activity of NADH dehydrogenase, and subsequently signaling, inducing the expression of nuclear genes involved in male sterility in this type of cytoplasmic male sterility.

Antibacterial activity of chitosan solution against Xanthomonas pathogenic bacteria isolated from Euphorbia pulcherrima

Abstract The antibacterial activity of chitosan solution against Xanthomonas pathogenic bacteria isolated from Euphorbia pulcherrima was investigated in this study. Results showed that chitosan solution at 0.10 mg/mL markedly inhibited the growth of Xanthomonas pathogenic bacteria from different geographical origins. The antibacterial activity of chitosan solution against the selected strain R22580 of Xanthomonas axonopodis pv. poinsettiicola increased with the increase of chitosan concentration up to 0.10 mg/mL. The antibacterial activity of chitosan solution was also enhanced by the addition of NaCl, but was unaffected by the type of nutrient and sterilization. In addition, chitosan solution exhibited strong antibacterial activity against strain R22580 over the pH range of 5.5–7.0. Overall, the results indicated that chitosan was a potential bactericide against bacterial pathogens of E. pulcherrima under different environmental conditions.

Progress in Research and Development on Hybrid Rice: A Super-domesticate in China

BackgroundChina has been successful in breeding hybrid rice strains, but is now facing challenges to develop new hybrids with high-yielding potential, better grain quality, and tolerance to biotic and abiotic stresses. This paper reviews the most significant advances in hybrid rice breeding in China, and presents a recent study on fine-mapping quantitative trait loci (QTLs) for yield traits.ScopeBy exploiting new types of male sterility, hybrid rice production in China has become more diversified. The use of inter-subspecies crosses has made an additional contribution to broadening the genetic diversity of hybrid rice and played an important role in the breeding of super rice hybrids in China. With the development and application of indica-inclined and japonica-inclined parental lines, new rice hybrids with super high-yielding potential have been developed and are being grown on a large scale. DNA markers for subspecies differentiation have been identified and applied, and marker-assisted selection performed for the development of restorer lines carrying disease resistance genes. The genetic basis of heterosis in highly heterotic hybrids has been studied, but data from these studies are insufficient to draw sound conclusions. In a QTL study using stepwise residual heterozygous lines, two linked intervals harbouring QTLs for yield traits were resolved, one of which was delimited to a 125-kb region.ConclusionsAdvances in rice genomic research have shed new light on the genetic study and germplasm utilization in rice. Molecular marker-assisted selection is a powerful tool to increase breeding efficiency, but much work remains to be done before this technique can be extended from major genes to QTLs.

Structural and Expressional Variations of the Mitochondrial Genome Conferring the Wild Abortive Type of Cytoplasmic Male Sterility in Rice

AbstractThe so‐called “wild abortive” (WA) type of cytoplasmic male sterility (CMS) derived from a wild rice species Oryza rufipogon has been extensively used for hybrid rice breeding. However, extensive analysis of the structure of the related mitochondrial genome has not been reported, and the CMS‐associated gene(s) remain unknown. In this study, we exploited a mitochondrial genome‐wide strategy to examine the structural and expressional variations in the mitochondrial genome conferring the CMS. The entire mitochondrial genomes of a CMS‐WA line and two normal fertile rice lines were amplified by Long‐polymerase chain reaction into tilling fragments of up to 15.2 kb. Restriction and DNA blotting analyses of these fragments revealed that structural variations occurred in several regions in the WA mitochondrial genome, as compared to those of the fertile lines. All of the amplified fragments covering the entire mitochondrial genome were used as RNA blot probes to examine the mitochondrial expression profile among the CMS‐WA and fertile lines. As a result, only two mRNAs were found to be differentially expressed between the CMS‐WA and the fertile lines, which were detected by a probe containing the nad5 and orf153 genes and the other having the ribosomal protein gene rpl5, respectively. These mRNAs are proposed to be the candidates for further identification and functional studies of the CMS gene.

Combination of reversible male sterility and doubled haploid production by targeted inactivation of cytoplasmic glutamine synthetase in developing anthers and pollen

Reversible male sterility and doubled haploid plant production are two valuable technologies in F(1)-hybrid breeding. F(1)-hybrids combine uniformity with high yield and improved agronomic traits, and provide self-acting intellectual property protection. We have developed an F(1)-hybrid seed technology based on the metabolic engineering of glutamine in developing tobacco anthers and pollen. Cytosolic glutamine synthetase (GS1) was inactivated in tobacco by introducing mutated tobacco GS genes fused to the tapetum-specific TA29 and microspore-specific NTM19 promoters. Pollen in primary transformants aborted close to the first pollen mitosis, resulting in male sterility. A non-segregating population of homozygous doubled haploid male-sterile plants was generated through microspore embryogenesis. Fertility restoration was achieved by spraying plants with glutamine, or by pollination with pollen matured in vitro in glutamine-containing medium. The combination of reversible male sterility with doubled haploid production results in an innovative environmentally friendly breeding technology. Tapetum-mediated sporophytic male sterility is of use in foliage crops, whereas microspore-specific gametophytic male sterility can be applied to any field crop. Both types of sterility preclude the release of transgenic pollen into the environment.

Rice UDP-Glucose Pyrophosphorylase1 Is Essential for Pollen Callose Deposition and Its Cosuppression Results in a New Type of Thermosensitive Genic Male Sterility

UDP-glucose pyrophosphorylase (UGPase) catalyzes the reversible production of glucose-1-phosphate and UTP to UDP-glucose and pyrophosphate. The rice (Oryza sativa) genome contains two homologous UGPase genes, Ugp1 and Ugp2. We report a functional characterization of rice Ugp1, which is expressed throughout the plant, with highest expression in florets, especially in pollen during anther development. Ugp1 silencing by RNA interference or cosuppression results in male sterility. Expressing a double-stranded RNA interference construct in Ugp1-RI plants resulted in complete suppression of both Ugp1 and Ugp2, together with various pleiotropic developmental abnormalities, suggesting that UGPase plays critical roles in plant growth and development. More importantly, Ugp1-cosuppressing plants contained unprocessed intron-containing primary transcripts derived from transcription of the overexpression construct. These aberrant transcripts undergo temperature-sensitive splicing in florets, leading to a novel thermosensitive genic male sterility. Pollen mother cells (PMCs) of Ugp1-silenced plants appeared normal before meiosis, but during meiosis, normal callose deposition was disrupted. Consequently, the PMCs began to degenerate at the early meiosis stage, eventually resulting in complete pollen collapse. In addition, the degeneration of the tapetum and middle layer was inhibited. These results demonstrate that rice Ugp1 is required for callose deposition during PMC meiosis and bridges the apoplastic unloading pathway and pollen development.

Allografts in Sports Medicine

Society has long recognized the medical importance of donating and transplanting organs and tissues. Allografts are used routinely for sports medicine applications and in a large variety of other non-sports related surgical procedures. Allogeneic tissue research has been influenced by the increase in demand for transplantable grafts for both non-sport and sport related surgeries. Disease transmission prevention is a key factor in the proliferation and success of the allografts used today. Disease transmission prevention methods are accomplished by social screening, serology, and various types of secondary sterilization. These methods are increasingly assessed and regulated by the FDA, the American Association of Tissue Banks and their accredited member organization tissue banks. Sports medicine surgeons initially used allografts to augment their autograft use when autologous sources were not available. While the number of grafts and types continue to grow, demand continues to increase as well. Some allografts undergo minimal processing and only require minor preparation prior to use, however other procedures require grafts that are sized dimensionally and matched for their recipients. Our continuing experience with a variety of allograft types has led us to conclude that allograft use is a legitimate primary or alternate source in the ligamentous or cartilage reconstruction or transplant in sports medicine. Cost and availability will always limit allograft usage; however concerns regarding inferior clinical results should not. Our experience and those reported by others, indicates that comparable clinical results can be obtained with the added benefit of reduced surgical morbidity by the use of allografts.

A Honglian CMS line of rice displays aberrant F0 of F0F1-ATPase

Honglian (HL) is one of the three major types of cytoplasmic male sterility (CMS) of rice (Oryza sativa L) that has been commercially used in hybrid production. In previous studies, the CMS in HL is shown to be associated with a chimeric gene orfH79 that is cotranscribed with an extra atp6 in mitochondria. This study demonstrated that the intact F0F1-ATPase in HL CMS line was specifically reduced in both of its protein quantity and enzyme activity, whereas its F1 sector was not affected. It implies that the F0 sector presents a labile linkage with F1. In the presence of fertility restorer gene, F0F1-ATPase can be recovered. Furthermore, orfH79 transcripts were preferentially polyadenylated, and consequently degraded rapidly in florets of the restored hybrid plants, indicating that the atp6-orfH79 is involved in the sterile phenotype. With inhibition of cytochrome pathway of electron transfer chain, the biomass of the sterile plants grown in dark was significantly lower than that of the fertile lines. However, the respiration measurements showed an increase in the electron transferring capacity in the sterile plants, suggesting that the reduction of biomass in sterile line was caused by the disruption of F0F1-ATPase.

Cytological and molecular characterization of a novel monogenic dominant GMS in Brassica napus L.

A novel genic male sterile (GMS) line in Brassica napus L., which was identified in 1999, was found to be controlled by a monogenic dominant gene, which we have designated as MDGMS. The microspores of the MDGMS abort before the degradation of the tapetal cell layer. The F1 fertility from any fertile lines crossed with MDGMS segregated and the ratio was close to 1:1. Bulked segregation analysis (BSA) was employed to identify random amplified polymorphic DNA (RAPD) markers linked to the Ms gene in MDGMS. Among 880 random 10-mer oligonucleotide primers screened against the bulk DNA of sterile and fertile, one primer S243 (5'-CTATGCCGAC-3') gave a repeatable 1500-bp DNA polymorphic segment S243(1500) between the two bulks. Analysis of individual plants of each bulks and other types of GMS and cytoplasmic male sterility (CMS) lines suggest that the RAPD marker S243(1500) is closely linked to the MDGMS locus in rapeseed. This RAPD marker has been converted into sequence characterized amplified region (SCAR) marker to aid identification of male-fertility genotypes in segregating progenies of MDGMS in marker-assisted selection (MAS) breeding programs.

Penampilan Fenotipik dan Tingkat Kemandulan Tepungsari Calon Galur Mandul Jantan Tipe Wild Abortive

Wild Abortive (WA) type of cytoplasmic male sterility (CMS) was developed by Indonesian Center of Rice Research, Sukamandi through backcross method. Pollen sterility and phenotypic acceptability evaluation of cytoplasmic male sterile (CMS) candidates were considered important in CMS development process. Both of evaluation were done during dry season 2002 and wet season 2002/2003. The materials were 18 CMS candidates and their resembled maintainers. Each line planting on two rows (2.5 m each) with 20 x 20 cm spacing. Observations were done for 50% flowering time, pollen sterility and phenotypic acceptability. The results of observations showed that : (a) the variation of pollen sterility among 18 CMS candidates were 82.5 - 100%; (b) Nine CMS candidates were consistent in sterility (100%) and good in phenotypic acceptability during the two seasons. Those lines were derived from IR62829A/BP1082, IR68897A/S3613F, IR66707A/Barumun, IR58025A/S24731, IR62829A/BP68C, IR68886A/IR71605, IR66707A/A2790, IR69622A/IRBB5 and IR68886A/T12357. The male parent as donor were elite lines with some good characters such as good eating quality, resistant to Rice Tungro Virus (RTV) and Bacterial Leaf Blight (BLB). Key words : Rice, cytoplasmic male sterile, pollen sterility, phenotypic acceptability

Genetic study on two maize male sterile mutants obtained by space mutagenesis

Two maize male sterile mutants were selected from the offspring of four maize inbred lines, which were carried into space by the Shenzhou spaceship 4. Their genetic characteristic and stability was analyzed in present study. Crosses were made between the male sterile plants and fertile plants from the same line, and other inbred lines with normal cytoplasm. The ratios of the sterile plants with the fertile plants in their F1, F2 generations, and their reciprocal backcross generations with the male sterile plants were calculated. The results showed that the characteristic in male sterility was stable in different years, different seasons and different locations, and was inheritable from generation to generation. This male sterile was controlled by a single nuclear recessive gene. Since no pollens or a few malformed pollens existed in the anther of the sterile plants, it was a completely sterile type.

PLANT REGENERATION FROM DIFFERENT EXPLANT TYPES OF STREPTOCARPUS SPEC. IN VITRO

In order to develop an in vitro regeneration protocol for different Streptocarpus species, we investigated the effects of three factors: surface sterilization, regeneration medium and explant type. For surface sterilization the influence of an ethanol (70%) treatment for 30 s was tested, before the explants were immersed in 1.5% sodium hypochlorite for 10 min. Our experiments showed no significant difference regarding contamination of explants between the surface sterilization with and without ethanol. On the other hand, the treatment with 70% ethanol led to damage of the leaf explants regarding regeneration, especially the number of shootlets. The variation of indole acetic acid (IAA) and benzylaminopurine (BAP) concentrations in the regeneration medium revealed, that a combination of 1.0 mg L IAA and 1.0 mg L -1 BAP was most efficient for shoot regeneration in three species (S1, S3, S4). However, the best quality and regeneration response of the fourth species (S7) was obtained with 1.0 mg L -1 IAA and 0.1 mg L -1 BAP. The differences of the most suitable combination of phytohormones showed, that it was not possible to designate a uniform optimal medium for all of Streptocarpus species. In addition, different explant types were compared. Taking into consideration the regeneration intensity, the expenditure of time for explant preparation and material costs, we concluded that the most suitable explant type were leaf blade explants.

Damage of oxidative stress on mitochondria during microspores development in Honglian CMS line of rice

One of the cytoplasmic male sterility (CMS) types used for hybrid rice (Oryza sativa L.) production in China is the Honglian (HL)-CMS. Previous studies suggested that pollen abortion of the sterile plants was resulted from a special programmed cell death (PCD) program started at meiosis in the microspores. To elucidate the molecular basis of the pollen abortion, we compared the biochemical and physiological properties such as content of reactive oxygen species (ROS), ATP, NADH, total glutathione and ascorbate acid, the activities of dehydroascrbate reductase, glutathione reductase, ascorbate peroxides and superoxide dismutase, and the integrity of mitochondrial genome DNA isolated from an HL-CMS line, Yuetai A and its maintainer line, Yuetai B. Our results indicated that the mitochondria of the HL-CMS line suffered from a serious oxidative stress during microspores development. Oxidative stress induced by abnormal increased ROS at meiosis stage resulted in the depletion of ATP and NADH, and the degradation of mitochondrial genomic DNA. This suggests that the presence of redox signal originated in mitochondria affects the rest of the cell. Therefore, it is possible that the abortion of premature microspores in HL-CMS line is induced by the chronic oxidative stress in mitochondria in the early stage of pollen development.

Transcript profiling of a dominant male sterile mutant ( Ms-cd1) in cabbage during flower bud development

A spontaneous male-sterile mutation affecting anther development has been identified in cabbage line 79-399-3. The male sterility was associated with abnormal callose degeneration and failure of microspore separation during anther development. Three pairs near-isogenic lines (NILs) with or without the dominant male sterility allele (MS-cd1) were profiled by cDNA-AFLP to detect differentially expressed genes during flower bud development. Out of 6500 transcript derived fragments (TDFs) inspected, 27 were differentially expressed between fertile and male sterile plants in all three sets of NILs. All 27 TDFs were sequenced and BLAST searching revealed that 14 out of 27 fragments were highly homologous to genes with known or predicted function in Arabidopsis. Moreover, three of these TDFs were homologous to genes involved in cell wall formation and degradation, including plant invertase/pectin methylesterase inhibitor (PMEI) and polysaccharide lyase. RT-PCR experiments revealed that PMEI was expressed strongly in the anther and filament. Analysis of a set of NILs with different male sterility types showed that PMEI was also not expressed in a Nigra CMS NIL, a recessive male sterile NIL and an Ogura CMS NIL compared to their corresponding fertile NILs. Based on both cytological and transcriptional data we suggest that the dominant MS-cd1 mutant gene may disrupts proper separation of pollens from tetrads, which leads to the suppressed expression of a number of genes including BoPMEI1, a gene likely involved in the degradation of pectin.

Influence of postzygotic reproductive isolation on the interspecific transmission of the paternal sex ratio chromosome inTrichogramma

AbstractThe paternal sex ratio (PSR) chromosome is a supernumerary chromosome that causes the destruction of the paternal chromosome set in the first mitosis in a fertilized egg. It is known from parasitoid wasps in the generaNasoniaandTrichogramma(Hymenoptera). In these haplodiploids, the egg fertilized by sperm carrying PSR matures as a haploid male that again carries, and is capable of transmitting, the PSR chromosome. Because of its unique transmission behavior, the PSR chromosome may be easily transmitted between species. This study tests whether the interspecific transmission of PSR betweenTrichogramma kaykaiPinto and Stouthamer andTrichogramma deionPinto and Oatman (Hymenoptera: Trichogrammatidae) is affected by two types of postzygotic reproductive isolation, i.e., hybrid inviability and hybrid sterility. The results show that PSR can rescue fertilized eggs that would normally be inviable in the interspecific cross and the rescued eggs develop into male offspring that carry PSR. The results suggest that the two types of postzygotic reproductive isolation have no effect on the transmission of PSR between the twoTrichogrammaspecies.

A contrast study about 2 type of sterilization of laparoscopic instruments

目的 探讨安全、快速的腹腔镜手术器械灭菌方法.方法将2套腹腔镜手术器械采用2种不同的灭菌方法即环氧乙烷+2%戊二醛灭菌和汇日灭菌器灭菌.腹腔镜手术器械分成2个部分即带电和非带电部分.第1套腹腔镜带电器械采用环氧乙烷干式灭菌12 h、非带电器械采用2%戊二醛浸泡灭菌10 h;第二套腹腔镜带电器械经严格防水处理后与非带电器械一同放入汇日灭菌器内快速低温湿灭菌40 min.结果2套腹腔镜手术器械采用环氧乙烷+2%戊二醛灭菌和汇日灭菌器灭菌,灭菌效果都达到100%.结论2种方法均能达到灭菌效果,但汇日灭菌方法仅需40 min,能满足临床连台手术快速、安全的要求。

Lack of Transmission of Vaccinia Virus

Lack of Transmission of Vaccinia Virus

Taxonomic revision of the Palaeozoic marattialean fern Acitheca Schimper

The Pennsylvanian genus Acitheca Schimper, 1879 is revised based on re-examination of the sterile types, plus evidence from well-preserved fertile and sterile material from Canada and the Czech Republic ( n = 750 specimens). Acitheca was an arborescent marattialean fern about 3.5 m high with large, tripinnate or quadripinnate fronds which produced Caulopteris -like frond scars on the trunk. Although its reproductive structures are similar to those of Asterotheca Presl, Acitheca differs in a number of characters of the sterile foliage (especially the venation), and its palynology. The veins fork at least twice (except in the smallest pinnules): after the first dichotomy, the upper branch divides and then the lower branch divides, producing polymorphopterid veining pattern. Synangia occur in two rows, one on either side of the midvein, and usually consist of four elongate sporangia that extend beyond the pinnule margin. Recovered in situ spores show a much greater ontogenetic variability than any other known Pennsylvanian marattialean; the size varies from 34 μm to 116 μm, and exine ornamentation from laevigate (immature spores), finely microgranulate to scabrate (intermediate spores), to microverrucate–microgranulate (mature spores). Three species are described in the paper: Acitheca polymorpha (Brongniart) Schimper, Acitheca ambigua (Sternberg) Němejc, and a new species Acitheca alii sp. nov. Distributional evidence suggests that Acitheca probably originated in eastern North America and Western Europe in middle Pennsylvanian, and towards the end of it its geographical range had extended to Eastern Europe, the Caucasus, and into Permian of China.

Isolation and Characterization of Wear Debris Generated in Patients Wearing Polyethylene Hylamer Inserts, Gamma Irradiated in Air

Hylamer polyethylene was used in the early 1990s to make hip-joint components. Clinical experience has shown that these components, if sterilized by gamma rays in the presence of oxygen, are easily affected by wear, which then leads to osteolysis. The authors analyzed polyethylene wear particles in seven patients who had received Hylamer polyethylene implants sterilized by gamma rays in air and had suffered prosthetic loosening. The results were compared to those of six controls, who had received traditional polyethylene implants, sterilized by the same method. The frequency distribution of globular and fibrillar particles was similar in both groups (38.5% in Hylamer, 45.2% in controls). The globular particles in the Hylamer samples had a mean area of 0.12 microm2, which was significantly lesser than that of the controls (0.30 microm2). The width of fibrillar particles in the Hylamer samples was significantly lesser than that of the controls. Therefore, the two materials, despite undergoing the same type of sterilization, produced different types of wear, due to their different properties. In conclusion, the difference in the morphology of Hylamer polyethylene wear particles in comparison with PCA might have caused a more intensive biological response, early and massive osteolysis, and therefore, early loosening.