雄性特异性抗原的研究进展

雄性特异性抗原为雄性动物特有,是引起同种雌性动物免疫排斥反应的物质的总称。这类物质广泛存在于哺乳动物及其他脊椎动物。依据其检测方式的不同,可分为细胞毒性T细胞相关性雄性特异性抗原和血清学相关性雄性特异性抗原。目前,已初步确定了几个细胞毒性T细胞相关性雄性特异性抗原的候选基因及抗原肽序列,它们都位于Y染色体上。对于血清学相关性雄性特异性抗原的研究则还处于初级阶段。近年发现了细胞毒性T细胞相关性雄性特异性抗原的抗体,揭示此两类物质具有内在的联系。     

The interaction between the immune response of rabbits to heterologous antigens and a primary infestation with Rhipicephalus evertsi evertsi

Rhipicephalus evertsi evertsi feeding on hosts inoculated with sheep red blood cells (SRBC) and bovine serum albumin (BSA) suppressed the primary antibody response to the two antigens. In addition, while the ticks paralysed most hosts in the studies, fatality associated with this toxicosis occurred only in rabbits which had received SRBC, either alone or with BSA. Only those hosts inoculated with BSA developed any resistance against the ticks, manifested by a slight reduction of engorged weights and development of anti-tick antibodies. These results suggest that R. e. evertsi infestation induces a degree of reduced host immune responsiveness to heterologous antigens.     

A human major histocompatibility complex (MHC) DNA probe recognizes goat genes

A human major histocompatibility complex (MHC) class II (DR-β) probe was hybridized with restriction enzyme digest of genomic DNA from 14 goats. Nine of the animals belonged to one family. Digestion of the DNA with the restriction enzyme Eco RI gave 7 fragments in 13 animals and 6 fragments in the last animal. No other polymorphism could be detected. Bam HI digestion gave from 3 to 6 fragments which displayed a considerable polymorphism. In the family studied, polymorphic fragments were inherited together with serologically defined lymphocyte antigen specificities believed to be coded for by MHC class I genes.     

HVT免疫鸡羽毛根中病毒抗原的检测

１日龄非免疫鸡,ＨＶＴ常规剂量免疫后,于第３周起,每周采集一次羽毛根,分别作常规ＭＤＶ琼扩抗原的检测,结果显示：在免疫后第３～８周检测,均未观察到特异性ＡＧＰ沉淀线;若取较多数量的富含羽髓的羽毛根,经２ｍｌ磷酸缓冲液（ＰＢＳ）浸提、浓缩胶浓缩约４０倍后,再作上述检测,则分别于免疫接种后的第３～５周都有特异性的ＡＧＰ沉淀线出现,且与感染细胞上清中浓缩的ＨＶＴ及ＭＤＶ琼扩抗原所形成的沉淀线基本吻合,而第６周检测时,仅与ＨＶＴ阳性血清呈微弱阳性,用同样方法对免疫后第６周后的检测结果均表明为阴性。由此推断,免疫鸡羽毛根中含有较低水平的、并与致病性ＭＤＶ抗原具有交叉反应性的ＨＶＴ琼扩抗原,但采用常规ＡＧＰ法不能直接检测到。     

Inter-sectional hybrids obtained from reciprocal crosses between Begonia semperflorens (section Begonia) and B. ‘Orange Rubra’ (section Gaerdita × section Pritzelia)

Inter-sectional hybrids were successfully obtained by the reciprocal crosses between 11 cultivars (including 6 diploids and 5 tetraploids) of Begonia semperflorens (SS & SSSS genomes) and B. ‘Orange Rubra’ (RR genome) with the aid of in vitro culture of mature or immature seeds on MS medium containing 0.1 mg l⁻¹ α-naphthylacetic acid, 0.1 mg l⁻¹ 6-benzyladenine, 10 mg l⁻¹ gibberellic acid, 30 g l⁻¹ sucrose and 2.5 g l⁻¹ gellan gum. Embryo rescue as ovary culture with immature seeds 12^th–16^th day after pollination (DAP) generally gave higher efficiency of plantlet formation, but in some cross combinations, culture of mature seeds (30 DAP) resulted in higher yield of plantlets. Flow cytometric analysis revealed that they were consisted of the plants with various genomic combinations (RS, RR, RSS, RRS, RRSS and RRRRSS) as estimated by the DNA contents of both parents. Hybridity of these plants with various genomic combinations including RR was confirmed by random amplified polymorphic DNA analysis. These results suggested that unreduced gamete formation and spontaneous chromosome doubling were involved in the hybrid formation of various ploidy levels and genomic combinations. These hybrids showed various levels of intermediate traits between both parents according to the genomic compositions, and some of them had desirable characters of both parents.     

2n配子在大白菜育种上的应用

对二倍体大白菜的８７个自交系和３个杂交一代材料进行了雌雄２ｎ配子的测定。结果有１２个材料含有２ｎ配子，占总数的１３．３％。其中有５份既含雄性２ｎ配子又含雌性２ｎ配子，占５．６％。用５个不同包球类型并含有２ｎ配子的二倍体大白菜与四倍体大白菜杂交，选育出具有不同熟性，抗逆性强（抗多种病害，抗寒，耐热）、品质优良，口感好，营养成份高，生长速度快，稔性正常，可在生产上应用的四倍体大白菜材料和多育１、２、３     

极端温度处理白杨雌花培育三倍体植株的研究

采用极端温度的物理方法处理毛新杨、银腺杨、银毛杨雌花芽，均可获得三倍体。结果表明：①雌花枝水倍１－５ｄ期间是处理雌花芽的有效时期；②高温处理化芽检测出１０株三倍体，处理温以４０，４４℃有效，分别获得８株、２株三倍体，其中４０℃高温处理效果最佳；③低温处理雌花芽检测出３株三倍体，４，－２℃低温处理均有效果，分别获得１株、２株三倍体，－２℃处理效果较好；④处理时间分别为：４０℃高温处理水倍１－５ｄ的花     

A tetraploid hybrid plant from 4x × 2x crosses in Vitis and its origin

To study the origin of unreduced (2n) gametes in diploid Vitis cultivars, we surveyed the occurrence of tetraploid hybrid seedlings from 40 interploid crosses with five tetraploid and seven diploid cultivars. A total of 250 seedlings from the interploid crosses were established through embryo culture and by seed sowing. In 20 2x × 4x crosses, no tetraploid hybrid seedlings were derived from 8,902pollinations. In 20 4x × 2x crosses, two tetraploid hybrid seedlings were obtained from 8,057 pollinations. Investigation of isozyme genotypes of the two tetraploid seedlings using three variable enzyme systems indicated that one of the two seedlings resulted from the union of a diploid egg with a 2n male gamete and that failure of second meiotic division resulted in the formation of the 2n male gamete. The percentage of giant pollen grains in `Muscat Bailey A', a pollen parent of the tetraploid seedling, was relatively high(about 5.9%) and 10.9% of the giant pollen grains germinated on agar medium. These results suggested that 2n pollen of diploid cultivars are useful for breeding tetraploid grape. This revised version was published online in August 2006 with corrections to the Cover Date.     

The occurrence of 2n-pollen and the origin of sexual polyploids in dihaploid roses (Rosa hybrida L.)

Haploidisation by in situ parthenogenesis of 4x R. hybrida resulted in the production of some dihaploid roses (2n=2x=14) able to produce viable pollen. A cytological study of microsporogenesis revealed that, although the first meiotic reductional division occurred normally, the second (equational) division was characterised by frequent abnormalities which concerned spindle formation and led to unreduced gametes of First Division Restitution (FDR) type. Analysis of the hybrid progeny of a parthenogenetically derived male fertile dihaploid plant revealed a selective advantage of the 2n-pollen, especially in the case of an hybridization with a tetraploid female parent. Moreover, crosses carried out among dihaploid partners always resulted in hybrids with ploidy levels≥ 3x. This revised version was published online in July 2006 with corrections to the Cover Date.