The Dominant white mutation in the PMEL17 gene does not cause visual impairment in chickens

Objective  To examine whether the Dominant white mutation (causing a hypopigmented phenotype in chicken) affects the visual ability and gives rise to ocular abnormalities in chickens ( Gallus gallus ).
Procedure  Chickens homozygous for either the Dominant white mutation or the wild-type alleles were tested in a visual contrast behavioral test and subjected to histological and ophthalmologic examination.
Results  There were no differences between the genotypes in the visual contrast behavioral test, and there were no abnormal structures among the Dominant white chickens in the ophthalmic examination. The histological sections from the Dominant white chickens did not differ from the wild-type chicken in structure, photoreceptor density, or RPE pigmentation.
Conclusions  The results indicate that the Dominant white mutation in PMEL17 does not seem to affect the visual ability or eye structures in chickens.     

Genetic male sterility in the pea (Pisum sativum L.)

Summary Genetic male sterility has been described in the pea (Pisum sativum L.), but no comprehensive effort has been made to study the phenomenon. A preceding companion paper reported the inheritance, allelism and linkage relations of thirteen male sterile mutants obtained from seed mutagen treatments. In the present study, the same male sterile mutants were investigated cytologically to determine the cause of sterility. Normal microsporogenesis and microgametogenesis was compared to that of the mutants. The ms-2, ms-3, and ms-4 mutants exhibited meiotic abnormalities similar to those described by Gottschalk and colleagues except that ms-3 had a high degree of female sterility. Chromosome clumping and spindle abnormalities leading to formation of coenocytic microspores and degeneration were characteristic of ms-2 and ms-4. The ms-2 and ms-4 mutants were previously found to be allelic, and were nearly identical cytologically in the present study. The ms-3 mutant exhibited a lack of chromosome condensation in meiosis I, and a lack of spindle formation in both meiotic divisions. Two mutations (ms-6 and ms-10) affected meiosis, with univalents at metaphase, and asynchronous divisions during meiosis II. Microspores of ms-6 completely degenerated whereas those of ms-10 showed some development. Sticky chromosomes, bridges and fragments, tripolar spindles, and lack of a second division were characteristic of ms-10. The ms-10 mutant also showed reduced female fertility. Two male steriles (ms-5 and ms-9) had abnormalities associated with premature degeneration of the tapetum. Three others (ms-7, ms-8, and ms-11) aborted pollen during meicrogametogenesis. Pollen grains of ms-11 had thinner walls than normal and lacked sculptured exine. The ms-10 mutant, and those affecting microgametogenesis (ms-5, ms-7, ms-8, ms-9, and ms-11) produced some stainable and viable pollen.     

Meiotic behavior in interspecific hybrids between Brachiaria ruziziensis and Brachiaria brizantha (Poaceae)

The meiotic behavior of two half-sib interspecific tetraploid (2n = 4x = 36) promising hybrids, a sexual and an apomictic one, from crosses B. ruziziensis and B. brizantha, was evaluated. Although chromosome paired predominantly as bivalents, a few tri- and quadrivalents were recorded. Results suggest that B. brizantha and B. ruziziensis are closely related and genetic recombination is expected in hybrids. Introgression of specific target genes from B. ruziziensis into B. brizantha and vice-versa may be foreseen. However, abnormalities such as irregular chromosome segregation, chromosome stickiness and abnormal cytokinesis reported in these hybrids affect pollen fertility. More than 65% of pollen grains are sterile. Since the distinctive cytological feature of these hybrids is abnormal cytokinesis, this fact suggests that both parental genomes are unable to coordinate their activities with regard to this cytological phenomenon. Deployment of such hybrids in the process of developing varieties is discussed.     

Heterotopic polydontia as a cause for a cystic lesion in the paranasal sinus of a Thoroughbred filly

A 1-year-old Thoroughbred filly with left bony facial distortion was diagnosed with a multilobar expansile mass within the caudal maxillary and frontal sinuses on computed tomography (CT). Typical findings associated with a sinus cyst, including expression of amber fluid from the mass and a thick lining that could be peeled from the sinus walls, were found on surgical exploration of the sinus under general anaesthesia. Histological examination of firm structures within the fluid-filled cyst contained all components of embryologically normal dental tissue. The filly recovered well and entered training to race as a 2-year-old, as remodelling of the bony distortion and narrowing of the nasal passage was sufficient for airflow. Previous reports of paranasal cystic lesions in horses suggest developmental abnormalities as a causative factor, especially in young horses. Furthermore, heterotopic polydontia is reported as the underlying aetiology in some human paranasal sinus cysts. While polydontia has been reported in the paranasal sinuses and nasal passages of horses, this is the first case report that finds them associated with a cystic lesion within the paranasal sinus.     

影响奶牛早期胚胎丢失的因素

早期胚胎丢失,即胚胎着床之前的胚胎死亡,是影响奶牛妊娠率的主要因素。奶牛妊娠早期的胚胎死亡率较高,给牧场造成了严重的经济损失。目前,对于早期胚胎丢失的研究主要集中在染色体异常、生殖激素紊乱、热应激、免疫因素、双胎妊娠、疾病、B族维生素缺乏等方面。本文综述了早期胚胎丢失发生的原因,为预防早期胚胎丢失提供依据。     

Temperature effects on early development and occurrence of metamorphosis-related morphological abnormalities in hatchery-reared brown sole Pseudopleuronectes herzensteini

The objectives of the present study are to elucidate the effects of rearing temperatures on early larval development and the occurrence of metamorphosis-related morphological abnormalities in hatchery-reared brown sole Pseudopleuronectes herzensteini. Newly hatched larvae were reared through metamorphosis at different temperatures (6, 9, 12, 15, 18, 21, and 24 °C). Growth and development of larvae were accelerated concomitant with higher temperatures. Metamorphosed juveniles were classified into four morphological categories as normal, pseudoalbinism (two types), and ambicoloration, in combination with body color (pigmentation) and eye location. Incidence of normal morphology was lowest (11–24%) and that of pseudoalbinism was highest (74–83%) at 12 °C. The highest incidence of normal morphology (51–73%) was obtained at 21 °C. Although occurrence of ambicoloration was very low in all temperature regimes (0–10%), it increased slightly with increasing temperatures. Results of the present study strongly suggested that rearing temperature during the larval period affected the appearance of normal fish because of the different larval growth and development.     

Eggshell apex abnormalities associated with Mycoplasma synoviae infection in layers

Eggs exhibiting eggshell apex abnormalities (EAA) were evaluated for changes in shell characteristics such as strength, thickness, and ultrastructure. Mycoplasma synoviae (MS) infection was confirmed by serological assay along with isolation of MS from the trachea and oviduct. Changes in eggshell quality were shown to be statistically significant (p < 0.01). We also identified ultrastructural changes in the mammillary knob layer by Scanning Electron Microscopy. While eggs may seem to be structurally sound, ultrastructural evaluation showed that affected eggs do not regain their former quality. In our knowledge, this is the first report describing the occurrence of EAA in Korea.     

Laboratory and clinical findings and their association with viral and proviral loads in cats naturally infected with feline leukemia virus

This study was conducted to correlate clinical, laboratory, and bone marrow (BM) changes in cats naturally infected with feline leukemia virus and their association with viral loads in blood and BM and proviral loads in BM. Cats were classified into five groups based on antigenemia, clinical and/or laboratory findings and viral/proviral loads, according to a prospective study: symptomatic progressive (GI); asymptomatic progressive (GII); regressive (GIII); unclassified (GIV); or healthy (GV). |Correlations between these five groups and viral/proviral loads were evaluated. High viral and proviral loads were detected in GI and GII and viral loads were significantly associated with laboratory signs. Proviral loads detected in BM were significantly lower in GIII and GIV. GI cats were more likely to develop hematopoietic disorders than those from the other groups. Hematological and clinical disorders and disease severity are related to higher viral blood and proviral BM loads.     

Mutagenic and genotoxic effects of the Atrazine herbicide in Oreochromis niloticus (Perciformes, Cichlidae) detected by the micronuclei test and the comet assay

Atrazine is the triazinic herbicide most found in the rural aquatic environments due to its extensive use and its stability in such places. The mutagenicity and the genotoxicity of different concentrations of the Atrazine herbicide were determinated by the micronucleus test and the comet assay, using Oreochromis niloticus as test-system. The tested concentrations of Atrazine herbicide were 6.25, 12.5 and 25 μg/L, both for the micronuclei test and for the comet assay. The results showed a significant rate of micronuclei and nuclear abnormalities for all the tested concentrations of Atrazine herbicide. For the comet assay, we also observed results significantly different from the control in 6.25, 12.5 and 25 μg/L concentrations. Due to these results, we could infer that such herbicide may be dangerous to the lives of those organisms exposed to it.     

Skeletal development and abnormalities of the vertebral column and fins in larval stage of hatchery‐reared American shad,Alosa sapidissima

The present study describes the skeletal development and the occurrence of deformities in American shad, Alosa sapidissima, larvae from hatching to 45 days after hatching (DAH). The ontogeny of the vertebral column started at 16 DAH (days after hatching), with the formation of the posterior neural and haemal arches, and was complete at 28 DAH. In comparison, the vertebral centra started to form at 16 DAH, with ossification being visible in all centra at 38 DAH. The pectorals were the only fins that formed before the onset of feeding (at 2 DAH), with ossification being complete at 45 DAH. The caudal fin formed at 5 DAH, with ossification being complete at 40 DAH. Dorsal and pelvic fin development began at 6 DAH and 20 DAH respectively. The ossification of both the dorsal and pelvic fins was visible at 45 DAH. The anal fin began forming at 14 DAH, and was complete at 30 DAH. The ossification of the anal fin was complete at 45 DAH. Overall, 22 types of skeletal deformities were detected in about 41% of individuals. Most anomalies were detected in the haemal region, while the fewest anomalies were detected in the anal fin. In addition, the frequency of deformities gradually increased with fish age at the different developmental stages. Our results are expected to contribute baseline information on how rearing conditions impact skeletal development, in addition to identifying potential causative factors of skeletal deformities.