Über das Vorkommen meiotischer und apomeiotischer Embryosäcke in der GattungFragaria (L.)

Zusammenfassung Bei der Sorte Mieze Schindler der GartenerdbeereFragaria × ananassa (Duchesne) und beiFragaria moschata Weston werden multizelluläre Archespore ausgebildet, welche in voll entwickelten Nuzelli aus 15–25 Zellen bestehen. Maximal 5 Zellen aus dem Archespor einer Samenanlage verändern sich durch auffällige Volumenzunahme und können in der Folge davon sowohl als Embryosackmutterzellen für eine meiotische Embryosackentwicklung als auch als Initialzellen für eine diplospore Embryosackentwicklung fungieren. Diplospore Embryosäcke entstehen bevorzugt nach demAntennaria-Typus, in etwas geringerer Häufigkeit aber auch nach demTaraxacum-Typus.Nuzelli mit mehreren Embryosäcken treten in beiden untersuchten Formen auf. In wenigen Fällen werden zwei meiotische Embryosäcke je Nuzellus beobachtet. Sofern mehr als zwei Embryosäcke je Nuzellus entstehen, sind die zusätzlichen in der Regel apomeiotischen Ursprungs. Von den im Stadium der Gametogenese analysierten Nuzelli mit einem Embryosack entstehen etwa die Hälfte auf meiotischem, die andere Hälfte auf apomeiotischem Wege.

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Meiotic and apomeiotic embryo sacs formation in the genusFragaria L.

Summary Multicellular female archesporium consisting of about 15 to 25 cells are formed in variety Mieze Schindler (Fragaria × ananassa Duchesne) andFragaria moschata Weston.Up to 5 cells of an archesporium change their shape by conspicuous volume extention and function in the further development as initials for meiotic or diplosporous embryo sac formation. Diplosporous embryo sac types arise according to theAntennaria- and theTaraxacum-Type, the former at a higher frequency than the latter.Nucelli with multiple embryo sacs are found in both forms. Only in a few cases two meiotic embryo sacs are observed in one nucellus. In most cases, additional embryo sacs are of apomeiotic origin. About one half of nucelli with single embryo sacs observed in the stage of gametogenesis develop embryo sace according to the meiotic, the other half according to the apomeiotic mode.

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Fragaria (L.)

[Fragaria × ananassa (Duchesne)] Fragaria moschata Weston , , , 15–25 . 5 , , , . , , Antennaria-, , Taraxacum-. . . , , , , , , . , , , , , — .

     

Interocular transfer of learning in horses (Equus caballus)

Interocular transfer (IOT) of pattern discriminationswas studied in two horses (Equus caballus). An Anglo-Arabian mare and a Paint gelding were monocularly occluded and conditioned to choose the positive stimulus in a simultaneous two-choice discrimination task. When a criterion of ≥18/20 correct responses over two consecutive blocks of 20 trials was reached, the trained eye was covered and the stimuli presented to the untrained eye. Testing was continued until criterion was reached with this eye. Four sets of stimuli were presented in this manner. Additionally, two reversal discrimination problems were tested. Stimuli consisted of two-dimensional black patterns on a white background and were presented in a vertical configuration. The horses demonstrated high levels of interocular transfer on the four problems and on the reversal discriminations. The results provide evidence that, contrary to beliefs held by many people, horses are capable of interhemispheric transfer of visual information.     

Nutritional assessment of seed proteins in rice bean [Vigna Umbellata (Thumb.) Ohwi and Ohashi

Seeds of three rice bean accessions had 17.26 to 21.42% protein, 3.46 to 4.03% fat, 61.09 to 64.73% carbohydrates 3.99 to 4.58% ash and 5.22 to 7.43% fiber (dry weight basis).The most limiting amino acids in the seed meal, albumin and globulin fractions, were methionine and cysteine with chemical scores of these fractions being 38% to 59%. The amino acid pattern of globulin and seed meal were similar.Thein vitro protein digestibility (IVPD) ranged from 82 to 86% for the seed meal, 86 to 88.5% for the albumin and 75.9 to 83.3% for the globulin. Relative nutritive values (RNV) of raw mature seed of two accessions were 22.6% and 42.4% and increased to 55.6% to 79.4% after boiling and roasting.Part of MS thesis of the senior author.     

DNA microarray-based genotyping of Chlamydophila psittaci strains from culture and clinical samples

The avian and human pathogen Chlamydophila (C.) psittaci represents a genetically heterogeneous species. To facilitate epidemiological surveys, more rapid yet highly specific molecular tests are needed. Currently used typing methods, i.e. serotyping and PCR-RFLP, have only limited sensitivity and are incapable of covering the wide spectrum of naturally occurring types of C. psittaci strains. In the present study, a new DNA microarray assay based on the ArrayTube (AT) technology was used to genotype C. psittaci in 98 isolates and 23 clinical tissue samples. The present array carries 35 oligonucleotide probes derived from variable domains 2 and 4 of the ompA gene. The assay proved highly sensitive, allowing correct genotyping of DNA from 2 inclusion-forming units. The results of DNA microarray genotyping of cultured strains proved highly concordant with the data from PCR-RFLP typing and serotyping. Sequencing of the ompA gene served as the reference test to verify the accuracy of AT genotyping results. In 15 instances (15.3%), strains were successfully typed by the AT assay, while serotyping and/or PCR-RFLP genotyping failed to produce unambiguous results. Eleven of these samples were ompA sequenced to confirm the AT findings. In addition to the currently accepted nine ompA genotypes, the microarray test was shown to recognise new provisional genotypes, such as Mat116 and YP84. In conclusion, the new AT assay proved to be suitable for rapid, sensitive and reproducible genotyping of C. psittaci strains and can be recommended for routine diagnosis.     

MAGNETIC RESONANCE IMAGING FEATURES OF INTRAVENTRICULAR EPENDYMOMAS IN Five CATS

Intraventricular ependymoma is a rare type of feline intracranial neoplasia and published information on magnetic resonance imaging (MRI) characteristics is currently lacking. The purpose of this retrospective case series study was to describe the clinical and MRI characteristics of histopathologically confirmed intraventricular ependymomas in a group of cats. Five cats met inclusion criteria. In relation to normal gray matter, ependymomas appeared hyperintense on T2W, T2W‐FLAIR, PD, and DW‐EPI images; isointense on ADC images; and had subtle to strong contrast enhancement. Some variability was seen on T2*GRE and on T1W images with masses being isointense to hyperintense. Four ependymomas were small and homogeneous, and one was centrally cavitated. All cats had obstructive hydrocephalus, transtentorial herniation, and foramen magnum herniation. Perilesional edema was identified in most cats but was questionable in one. Intraventricular ependymoma should be considered as a differential diagnosis for cats with this combination of MRI signs.     

Discussing overweight in dogs during a regular consultation in general practice in the Netherlands

In previous studies, it has been demonstrated that, similar to general practitioners, veterinarians find it difficult to discuss overweight in dogs. This study aimed to provide insight in the barriers and motivators for veterinarians to discuss overweight in dogs and to compare the results with findings from human medicine. Sub-hypotheses were postulated based on existing literature to investigate if lack of time, fear of offending clients, or lack of skills were potential barriers, and if feeling responsible and feeling compassion were potential motivators for veterinarians to discuss overweight in dogs. To this end, an online survey (n = 59) was conducted. Furthermore, 15 small animal clinicians working in general practice were interviewed by semi-structured face-to-face interviews. Results from the online survey indicated that veterinarians find it sometimes difficult to discuss overweight in dogs. Veterinarians who responded to the online survey did not experience strong barriers but did make use of motivators (e.g. feeling responsible and feeling compassion) when discussing overweight in dogs. Interestingly, results from the semi-structured face-to-face interviews showed that the responding veterinarians did experience strong barriers, as well as motivators, when discussing overweight in dogs with their clients. The most prominent barrier was customer dissatisfaction, whereas lack of time and lack of skills were also experienced. The most prominent motivator was feeling responsible for animal health and preventive veterinary medicine. These findings were strikingly similar to previous research on discussing childhood overweight by general practitioners. To improve treatment and prevention of overweight in dogs, veterinarians need more communication skills and should be more aware of the motivators that drive their self-motivation. Improving awareness on overweight and its comorbidities should be a One Health issue.     

Effects of social network factors on information acquisition and adoption of improved groundnut varieties: the case of Uganda and Kenya

Social networks play a significant role in learning and thus in farmers’ adoption of new agricultural technologies. This study examined the effects of social network factors on information acquisition and adoption of new seed varieties among groundnut farmers in Uganda and Kenya. The data were generated through face-to-face interviews from a random sample of 461 farmers, 232 in Uganda and 229 in Kenya. To assess these effects two alternative econometric models were used: a seemingly unrelated bivariate probit (SUBP) model and a recursive bivariate probit (RBP) model. The statistical evaluation of the SUBP shows that information acquisition and adoption decisions are interrelated while tests for the RBP do not support this latter model. Therefore, the analysis is based on the results obtained from the SUBP. These results reveal that social network factors, particularly weak ties with external support (e.g., researchers, extension agents, etc.), partially influence information acquisition, but do not influence adoption. In Uganda, external support, gender, farm size, and geographic location have an impact on information acquisition. In Kenya, external support and geographic location also have an impact on information acquisition. With regard to adoption, gender, household size, and geographic location play the most important roles for Ugandan farmers, while in Kenya information from external sources, education, and farm size affect adoption choice. The study provides insight on the importance of external weak ties in groundnut farming, and a need to understand regional differences along gender lines while developing agricultural strategies. This study further illustrates the importance of farmer participation in applied technology research and the impact of social interactions among farmers and external agents.     

Applying morphometrics to choose optimal captive brood stock for an endangered species: a case study using the freshwater pearl mussel,Margaritifera margaritifera (L.)

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